From 10b1fa68f366d51c6ef7f9df05772e6bdcc812fb Mon Sep 17 00:00:00 2001
From: Tpt <thomaspt@hotmail.fr>
Date: Thu, 16 Jan 2020 18:21:06 +0100
Subject: [PATCH] Adds native xsd:duration xsd:dateTime xsd:date and xsd:time
 structures

---
 lib/Cargo.toml                   |    8 +-
 lib/src/model/literal.rs         |   34 +-
 lib/src/model/xsd/date_time.rs   | 1613 ++++++++++++++++++++++++++++++
 lib/src/model/xsd/decimal.rs     |  232 ++++-
 lib/src/model/xsd/duration.rs    |  382 +++++++
 lib/src/model/xsd/mod.rs         |    8 +-
 lib/src/model/xsd/parser.rs      |  462 +++++++++
 lib/src/sparql/eval.rs           |  329 +++---
 lib/src/sparql/plan.rs           |    1 +
 lib/src/sparql/plan_builder.rs   |    8 +
 lib/src/store/mod.rs             |    1 -
 lib/src/store/numeric_encoder.rs |  216 ++--
 lib/tests/sparql_test_cases.rs   |    2 +
 13 files changed, 2925 insertions(+), 371 deletions(-)
 create mode 100644 lib/src/model/xsd/date_time.rs
 create mode 100644 lib/src/model/xsd/duration.rs
 create mode 100644 lib/src/model/xsd/parser.rs

diff --git a/lib/Cargo.toml b/lib/Cargo.toml
index 1ad28f2b..482a210d 100644
--- a/lib/Cargo.toml
+++ b/lib/Cargo.toml
@@ -18,7 +18,6 @@ rocksdb = { version = "0.13", optional = true }
 byteorder = { version = "1", features = ["i128"] }
 quick-xml = "0.17"
 num-traits = "0.2"
-chrono = "0.4"
 rand = "0.7"
 md-5 = "0.8"
 sha-1 = "0.8"
@@ -26,10 +25,11 @@ sha2 = "0.8"
 digest = "0.8"
 failure = "0.1"
 regex = "1"
-rio_api = "0.4"
-rio_turtle = "0.4"
-rio_xml = "0.4"
+rio_api = "0.3"
+rio_turtle = "0.3"
+rio_xml = "0.3"
 hex = "0.4"
+nom = "5"
 
 [dev-dependencies]
 rayon = "1"
diff --git a/lib/src/model/literal.rs b/lib/src/model/literal.rs
index bd52cefc..b2c0c4d8 100644
--- a/lib/src/model/literal.rs
+++ b/lib/src/model/literal.rs
@@ -1,8 +1,7 @@
 use crate::model::named_node::NamedNode;
 use crate::model::vocab::rdf;
 use crate::model::vocab::xsd;
-use crate::model::xsd::Decimal;
-use chrono::prelude::*;
+use crate::model::xsd::*;
 use rio_api::model as rio;
 use std::borrow::Cow;
 use std::fmt;
@@ -237,8 +236,8 @@ impl From<Decimal> for Literal {
     }
 }
 
-impl From<Date<FixedOffset>> for Literal {
-    fn from(value: Date<FixedOffset>) -> Self {
+impl From<Date> for Literal {
+    fn from(value: Date) -> Self {
         Literal(LiteralContent::TypedLiteral {
             value: value.to_string(),
             datatype: xsd::DATE.clone(),
@@ -246,17 +245,8 @@ impl From<Date<FixedOffset>> for Literal {
     }
 }
 
-impl From<NaiveDate> for Literal {
-    fn from(value: NaiveDate) -> Self {
-        Literal(LiteralContent::TypedLiteral {
-            value: value.to_string(),
-            datatype: xsd::DATE.clone(),
-        })
-    }
-}
-
-impl From<NaiveTime> for Literal {
-    fn from(value: NaiveTime) -> Self {
+impl From<Time> for Literal {
+    fn from(value: Time) -> Self {
         Literal(LiteralContent::TypedLiteral {
             value: value.to_string(),
             datatype: xsd::TIME.clone(),
@@ -264,20 +254,20 @@ impl From<NaiveTime> for Literal {
     }
 }
 
-impl From<DateTime<FixedOffset>> for Literal {
-    fn from(value: DateTime<FixedOffset>) -> Self {
+impl From<DateTime> for Literal {
+    fn from(value: DateTime) -> Self {
         Literal(LiteralContent::TypedLiteral {
-            value: value.to_rfc3339(),
+            value: value.to_string(),
             datatype: xsd::DATE_TIME.clone(),
         })
     }
 }
 
-impl From<NaiveDateTime> for Literal {
-    fn from(value: NaiveDateTime) -> Self {
+impl From<Duration> for Literal {
+    fn from(value: Duration) -> Self {
         Literal(LiteralContent::TypedLiteral {
-            value: value.format("%Y-%m-%dT%H:%M:%S%.f").to_string(),
-            datatype: xsd::DATE_TIME.clone(),
+            value: value.to_string(),
+            datatype: xsd::DURATION.clone(),
         })
     }
 }
diff --git a/lib/src/model/xsd/date_time.rs b/lib/src/model/xsd/date_time.rs
new file mode 100644
index 00000000..e16d79bc
--- /dev/null
+++ b/lib/src/model/xsd/date_time.rs
@@ -0,0 +1,1613 @@
+use super::parser::{date_lexical_rep, date_time_lexical_rep, parse_value, time_lexical_rep};
+use super::{Decimal, Duration, XsdParseError};
+use rand::distributions::weighted::alias_method::Weight;
+use std::cmp::{min, Ordering};
+use std::convert::{TryFrom, TryInto};
+use std::error::Error;
+use std::fmt;
+use std::hash::{Hash, Hasher};
+use std::str::FromStr;
+use std::time::{SystemTime, SystemTimeError};
+
+/// [XML Schema `dateTime` datatype](https://www.w3.org/TR/xmlschema11-2/#dateTime) implementation.
+#[derive(Eq, PartialEq, PartialOrd, Debug, Clone, Copy, Hash)]
+pub struct DateTime {
+    timestamp: Timestamp,
+}
+
+impl DateTime {
+    pub(super) fn new(
+        year: i64,
+        month: u8,
+        day: u8,
+        hour: u8,
+        minute: u8,
+        second: Decimal,
+        timezone_offset: Option<TimezoneOffset>,
+    ) -> Result<Self, DateTimeError> {
+        Ok(Self {
+            timestamp: Timestamp::new(DateTimeSevenPropertyModel {
+                year: Some(year),
+                month: Some(month),
+                day: Some(day),
+                hour: Some(hour),
+                minute: Some(minute),
+                second: Some(second),
+                timezone_offset,
+            })?,
+        })
+    }
+
+    pub fn now() -> Result<Self, DateTimeError> {
+        Ok(Self {
+            timestamp: Timestamp::now()?,
+        })
+    }
+
+    pub fn from_le_bytes(bytes: [u8; 18]) -> Self {
+        Self {
+            timestamp: Timestamp::from_le_bytes(bytes),
+        }
+    }
+}
+
+/// Conversion according to [XPath cast rules](https://www.w3.org/TR/xpath-functions/#casting-to-datetimes).
+impl From<Date> for DateTime {
+    fn from(date: Date) -> Self {
+        DateTime::new(
+            date.year(),
+            date.month(),
+            date.day(),
+            0,
+            0,
+            Decimal::default(),
+            date.timezone_offset(),
+        )
+        .unwrap()
+    }
+}
+
+impl FromStr for DateTime {
+    type Err = XsdParseError;
+
+    fn from_str(input: &str) -> Result<Self, XsdParseError> {
+        parse_value(date_time_lexical_rep, input)
+    }
+}
+
+impl fmt::Display for DateTime {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let year = self.year();
+        if year < 0 {
+            write!(f, "-")?;
+        }
+        write!(
+            f,
+            "{:04}-{:02}-{:02}T{:02}:{:02}:{:02}",
+            year.abs(),
+            self.month(),
+            self.day(),
+            self.hour(),
+            self.minute(),
+            self.second()
+        )?;
+        if let Some(timezone_offset) = self.timezone_offset() {
+            write!(f, "{}", timezone_offset)?;
+        }
+        Ok(())
+    }
+}
+
+impl DateTime {
+    /// [fn:year-from-dateTime](https://www.w3.org/TR/xpath-functions/#func-year-from-dateTime)
+    pub fn year(&self) -> i64 {
+        self.timestamp.year()
+    }
+
+    /// [fn:month-from-dateTime](https://www.w3.org/TR/xpath-functions/#func-month-from-dateTime)
+    pub fn month(&self) -> u8 {
+        self.timestamp.month()
+    }
+
+    /// [fn:day-from-dateTime](https://www.w3.org/TR/xpath-functions/#func-day-from-dateTime)
+    pub fn day(&self) -> u8 {
+        self.timestamp.day()
+    }
+
+    /// [fn:hour-from-dateTime](https://www.w3.org/TR/xpath-functions/#func-hour-from-dateTime)
+    pub fn hour(&self) -> u8 {
+        self.timestamp.hour()
+    }
+
+    /// [fn:minute-from-dateTime](https://www.w3.org/TR/xpath-functions/#func-minute-from-dateTime)
+    pub fn minute(&self) -> u8 {
+        self.timestamp.minute()
+    }
+
+    /// [fn:second-from-dateTime](https://www.w3.org/TR/xpath-functions/#func-second-from-dateTime)
+    pub fn second(&self) -> Decimal {
+        self.timestamp.second()
+    }
+
+    /// [fn:timezone-from-dateTime](https://www.w3.org/TR/xpath-functions/#func-timezone-from-dateTime)
+    pub fn timezone(&self) -> Option<Duration> {
+        Some(self.timezone_offset()?.into())
+    }
+
+    pub fn timezone_offset(&self) -> Option<TimezoneOffset> {
+        self.timestamp.timezone_offset()
+    }
+
+    fn properties(&self) -> DateTimeSevenPropertyModel {
+        DateTimeSevenPropertyModel {
+            year: Some(self.year()),
+            month: Some(self.month()),
+            day: Some(self.day()),
+            hour: Some(self.hour()),
+            minute: Some(self.minute()),
+            second: Some(self.second()),
+            timezone_offset: self.timezone_offset(),
+        }
+    }
+
+    pub fn to_le_bytes(&self) -> [u8; 18] {
+        self.timestamp.to_le_bytes()
+    }
+
+    /// [op:subtract-dateTimes](https://www.w3.org/TR/xpath-functions/#func-subtract-dateTimes)
+    pub fn checked_sub(&self, rhs: impl Into<Self>) -> Option<Duration> {
+        self.timestamp.checked_sub(rhs.into().timestamp)
+    }
+
+    /// [op:add-yearMonthDuration-to-dateTime](https://www.w3.org/TR/xpath-functions/#func-add-yearMonthDuration-to-dateTime) and [op:add-dayTimeDuration-to-dateTime](https://www.w3.org/TR/xpath-functions/#func-add-dayTimeDuration-to-dateTime)
+    pub fn checked_add_duration(&self, rhs: impl Into<Duration>) -> Option<Self> {
+        let rhs = rhs.into();
+        if rhs.all_months() == 0 {
+            Some(Self {
+                timestamp: self.timestamp.checked_add_seconds(rhs.all_seconds())?,
+            })
+        } else {
+            Some(Self {
+                timestamp: Timestamp::new(date_time_plus_duration(rhs, self.properties())?).ok()?,
+            })
+        }
+    }
+
+    /// [op:sub-yearMonthDuration-from-dateTime](https://www.w3.org/TR/xpath-functions/#func-sub-yearMonthDuration-from-dateTime) and [op:sub-dayTimeDuration-from-dateTime](https://www.w3.org/TR/xpath-functions/#func-sub-dayTimeDuration-from-dateTime)
+    pub fn checked_sub_duration(&self, rhs: impl Into<Duration>) -> Option<Self> {
+        let rhs = rhs.into();
+        if rhs.all_months() == 0 {
+            Some(Self {
+                timestamp: self.timestamp.checked_sub_seconds(rhs.all_seconds())?,
+            })
+        } else {
+            Some(Self {
+                timestamp: Timestamp::new(date_time_plus_duration(-rhs, self.properties())?)
+                    .ok()?,
+            })
+        }
+    }
+}
+
+/// [XML Schema `time` datatype](https://www.w3.org/TR/xmlschema11-2/#time) implementation.
+#[derive(Eq, PartialEq, PartialOrd, Debug, Clone, Copy, Hash)]
+pub struct Time {
+    timestamp: Timestamp,
+}
+
+impl Time {
+    pub(super) fn new(
+        mut hour: u8,
+        minute: u8,
+        second: Decimal,
+        timezone_offset: Option<TimezoneOffset>,
+    ) -> Result<Self, DateTimeError> {
+        if hour == 24 && minute == 0 && second == Decimal::default() {
+            hour = 0;
+        }
+        Ok(Self {
+            timestamp: Timestamp::new(DateTimeSevenPropertyModel {
+                year: None,
+                month: None,
+                day: None,
+                hour: Some(hour),
+                minute: Some(minute),
+                second: Some(second),
+                timezone_offset,
+            })?,
+        })
+    }
+
+    pub fn from_le_bytes(bytes: [u8; 18]) -> Self {
+        Self {
+            timestamp: Timestamp::from_le_bytes(bytes),
+        }
+    }
+}
+
+/// Conversion according to [XPath cast rules](https://www.w3.org/TR/xpath-functions/#casting-to-datetimes).
+impl From<DateTime> for Time {
+    fn from(date_time: DateTime) -> Self {
+        Time::new(
+            date_time.hour(),
+            date_time.minute(),
+            date_time.second(),
+            date_time.timezone_offset(),
+        )
+        .unwrap()
+    }
+}
+
+impl FromStr for Time {
+    type Err = XsdParseError;
+
+    fn from_str(input: &str) -> Result<Self, XsdParseError> {
+        parse_value(time_lexical_rep, input)
+    }
+}
+
+impl fmt::Display for Time {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
+            "{:02}:{:02}:{:02}",
+            self.hour(),
+            self.minute(),
+            self.second()
+        )?;
+        if let Some(timezone_offset) = self.timezone_offset() {
+            write!(f, "{}", timezone_offset)?;
+        }
+        Ok(())
+    }
+}
+
+impl Time {
+    /// [fn:hour-from-time](https://www.w3.org/TR/xpath-functions/#func-hour-from-time)
+    pub fn hour(&self) -> u8 {
+        self.timestamp.hour()
+    }
+
+    /// [fn:minute-from-time](https://www.w3.org/TR/xpath-functions/#func-minute-from-time)
+    pub fn minute(&self) -> u8 {
+        self.timestamp.minute()
+    }
+
+    /// [fn:second-from-time](https://www.w3.org/TR/xpath-functions/#func-second-from-time)
+    pub fn second(&self) -> Decimal {
+        self.timestamp.second()
+    }
+
+    /// [fn:timezone-from-time](https://www.w3.org/TR/xpath-functions/#func-timezone-from-time)
+    pub fn timezone(&self) -> Option<Duration> {
+        Some(self.timezone_offset()?.into())
+    }
+
+    pub fn timezone_offset(&self) -> Option<TimezoneOffset> {
+        self.timestamp.timezone_offset()
+    }
+
+    pub fn to_le_bytes(&self) -> [u8; 18] {
+        self.timestamp.to_le_bytes()
+    }
+
+    /// [op:subtract-times](https://www.w3.org/TR/xpath-functions/#func-subtract-times)
+    pub fn checked_sub(&self, rhs: impl Into<Self>) -> Option<Duration> {
+        self.timestamp.checked_sub(rhs.into().timestamp)
+    }
+
+    /// [op:add-dayTimeDuration-to-time](https://www.w3.org/TR/xpath-functions/#func-add-dayTimeDuration-to-time)
+    pub fn checked_add_duration(&self, rhs: impl Into<Duration>) -> Option<Self> {
+        let rhs = rhs.into();
+        Some(
+            DateTime::new(
+                1972,
+                12,
+                31,
+                self.hour(),
+                self.minute(),
+                self.second(),
+                self.timezone_offset(),
+            )
+            .ok()?
+            .checked_add_duration(rhs)?
+            .into(),
+        )
+    }
+
+    /// [op:sub-dayTimeDuration-from-time](https://www.w3.org/TR/xpath-functions/#func-sub-dayTimeDuration-from-time)
+    pub fn checked_sub_duration(&self, rhs: impl Into<Duration>) -> Option<Self> {
+        let rhs = rhs.into();
+        Some(
+            DateTime::new(
+                1972,
+                12,
+                31,
+                self.hour(),
+                self.minute(),
+                self.second(),
+                self.timezone_offset(),
+            )
+            .ok()?
+            .checked_sub_duration(rhs)?
+            .into(),
+        )
+    }
+}
+
+/// [XML Schema `date` datatype](https://www.w3.org/TR/xmlschema11-2/#date) implementation.
+#[derive(Eq, PartialEq, PartialOrd, Debug, Clone, Copy, Hash)]
+pub struct Date {
+    timestamp: Timestamp,
+}
+
+impl Date {
+    pub(super) fn new(
+        year: i64,
+        month: u8,
+        day: u8,
+        timezone_offset: Option<TimezoneOffset>,
+    ) -> Result<Self, DateTimeError> {
+        Ok(Self {
+            timestamp: Timestamp::new(DateTimeSevenPropertyModel {
+                year: Some(year),
+                month: Some(month),
+                day: Some(day),
+                hour: None,
+                minute: None,
+                second: None,
+                timezone_offset,
+            })?,
+        })
+    }
+
+    pub fn from_le_bytes(bytes: [u8; 18]) -> Self {
+        Self {
+            timestamp: Timestamp::from_le_bytes(bytes),
+        }
+    }
+}
+
+/// Conversion according to [XPath cast rules](https://www.w3.org/TR/xpath-functions/#casting-to-datetimes).
+impl From<DateTime> for Date {
+    fn from(date_time: DateTime) -> Self {
+        Date::new(
+            date_time.year(),
+            date_time.month(),
+            date_time.day(),
+            date_time.timezone_offset(),
+        )
+        .unwrap()
+    }
+}
+
+impl FromStr for Date {
+    type Err = XsdParseError;
+
+    fn from_str(input: &str) -> Result<Self, XsdParseError> {
+        parse_value(date_lexical_rep, input)
+    }
+}
+
+impl fmt::Display for Date {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let year = self.year();
+        if year < 0 {
+            write!(f, "-")?;
+        }
+        write!(f, "{:04}-{:02}-{:02}", year.abs(), self.month(), self.day())?;
+        if let Some(timezone_offset) = self.timezone_offset() {
+            write!(f, "{}", timezone_offset)?;
+        }
+        Ok(())
+    }
+}
+
+impl Date {
+    /// [fn:year-from-date](https://www.w3.org/TR/xpath-functions/#func-year-from-date)
+    pub fn year(&self) -> i64 {
+        self.timestamp.year()
+    }
+
+    /// [fn:month-from-date](https://www.w3.org/TR/xpath-functions/#func-month-from-date)
+    pub fn month(&self) -> u8 {
+        self.timestamp.month()
+    }
+
+    /// [fn:day-from-date](https://www.w3.org/TR/xpath-functions/#func-day-from-date)
+    pub fn day(&self) -> u8 {
+        self.timestamp.day()
+    }
+
+    /// [fn:timezone-from-date](https://www.w3.org/TR/xpath-functions/#func-timezone-from-date)
+    pub fn timezone(&self) -> Option<Duration> {
+        Some(self.timezone_offset()?.into())
+    }
+
+    pub fn timezone_offset(&self) -> Option<TimezoneOffset> {
+        self.timestamp.timezone_offset()
+    }
+
+    pub fn to_le_bytes(&self) -> [u8; 18] {
+        self.timestamp.to_le_bytes()
+    }
+
+    /// [op:subtract-dates](https://www.w3.org/TR/xpath-functions/#func-subtract-dates)
+    pub fn checked_sub(&self, rhs: impl Into<Self>) -> Option<Duration> {
+        self.timestamp.checked_sub(rhs.into().timestamp)
+    }
+
+    /// [op:add-yearMonthDuration-to-date](https://www.w3.org/TR/xpath-functions/#func-add-yearMonthDuration-to-date) and [op:add-dayTimeDuration-to-dateTime](https://www.w3.org/TR/xpath-functions/#func-add-dayTimeDuration-to-date)
+    pub fn checked_add_duration(&self, rhs: impl Into<Duration>) -> Option<Self> {
+        Some(DateTime::from(*self).checked_add_duration(rhs)?.into())
+    }
+
+    /// [op:sub-yearMonthDuration-from-date](https://www.w3.org/TR/xpath-functions/#func-sub-yearMonthDuration-from-date) and [op:sub-dayTimeDuration-from-date](https://www.w3.org/TR/xpath-functions/#func-sub-dayTimeDuration-from-date)
+    pub fn checked_sub_duration(&self, rhs: impl Into<Duration>) -> Option<Self> {
+        Some(DateTime::from(*self).checked_sub_duration(rhs)?.into())
+    }
+}
+
+#[derive(Eq, PartialEq, Debug, Clone, Copy, Hash)]
+pub struct TimezoneOffset {
+    offset: i16, // in minute with respect to UTC
+}
+
+impl TimezoneOffset {
+    pub const fn utc() -> Self {
+        Self { offset: 0 }
+    }
+
+    /// From offset in minute with respect to UTC
+    pub(super) const fn new(offset: i16) -> Self {
+        Self { offset }
+    }
+
+    pub fn from_le_bytes(bytes: [u8; 2]) -> Self {
+        TimezoneOffset {
+            offset: i16::from_le_bytes(bytes),
+        }
+    }
+}
+
+impl From<i16> for TimezoneOffset {
+    fn from(offset: i16) -> Self {
+        TimezoneOffset { offset }
+    }
+}
+
+impl From<TimezoneOffset> for Duration {
+    fn from(value: TimezoneOffset) -> Self {
+        Duration::new(0, i32::from(value.offset) * 60)
+    }
+}
+
+impl fmt::Display for TimezoneOffset {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.offset {
+            0 => write!(f, "Z"),
+            offset if offset < 0 => write!(f, "-{:02}:{:02}", -offset / 60, -offset % 60),
+            offset => write!(f, "+{:02}:{:02}", offset / 60, offset % 60),
+        }
+    }
+}
+
+impl TimezoneOffset {
+    pub fn to_le_bytes(self) -> [u8; 2] {
+        self.offset.to_le_bytes()
+    }
+}
+
+/// [The Date/time Seven-property model](https://www.w3.org/TR/xmlschema11-2/#dt-dt-7PropMod)
+#[derive(Eq, PartialEq, Debug, Clone, Hash)]
+struct DateTimeSevenPropertyModel {
+    year: Option<i64>,
+    month: Option<u8>,
+    day: Option<u8>,
+    hour: Option<u8>,
+    minute: Option<u8>,
+    second: Option<Decimal>,
+    timezone_offset: Option<TimezoneOffset>,
+}
+
+#[derive(Debug, Clone, Copy)]
+struct Timestamp {
+    value: Decimal,
+    timezone_offset: Option<TimezoneOffset>,
+}
+
+impl PartialEq for Timestamp {
+    fn eq(&self, other: &Self) -> bool {
+        match (self.timezone_offset, other.timezone_offset) {
+            (Some(_), Some(_)) | (None, None) => self.value.eq(&other.value),
+            _ => false, //TODO: implicit timezone
+        }
+    }
+}
+
+impl Eq for Timestamp {}
+
+impl PartialOrd for Timestamp {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        match (self.timezone_offset, other.timezone_offset) {
+            (Some(_), Some(_)) | (None, None) => self.value.partial_cmp(&other.value),
+            (Some(_), None) => {
+                let plus_result = self
+                    .value
+                    .partial_cmp(&(other.value.checked_add(14 * 3600)?));
+                let minus_result = self
+                    .value
+                    .partial_cmp(&(other.value.checked_sub(14 * 3600)?));
+                if plus_result == minus_result {
+                    plus_result
+                } else {
+                    None
+                }
+            }
+            (None, Some(_)) => {
+                let plus_result = self.value.checked_add(14 * 3600)?.partial_cmp(&other.value);
+                let minus_result = self.value.checked_sub(14 * 3600)?.partial_cmp(&other.value);
+                if plus_result == minus_result {
+                    plus_result
+                } else {
+                    None
+                }
+            }
+        }
+    }
+}
+
+impl Hash for Timestamp {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.value.hash(state)
+    }
+}
+
+impl Timestamp {
+    fn new(props: DateTimeSevenPropertyModel) -> Result<Self, DateTimeError> {
+        // Validation
+        if let (Some(day), Some(month)) = (props.day, props.month) {
+            // Constraint: Day-of-month Values
+            if day > days_in_month(props.year, month) {
+                return Err(DateTimeError {
+                    kind: DateTimeErrorKind::InvalidDayOfMonth { day, month },
+                });
+            }
+        }
+
+        Ok(Self {
+            timezone_offset: props.timezone_offset,
+            value: time_on_timeline(props).ok_or_else(|| DateTimeError {
+                kind: DateTimeErrorKind::Overflow,
+            })?,
+        })
+    }
+
+    fn now() -> Result<Self, DateTimeError> {
+        Timestamp::new(
+            date_time_plus_duration(
+                SystemTime::now()
+                    .duration_since(SystemTime::UNIX_EPOCH)?
+                    .try_into()
+                    .map_err(|_| DateTimeError {
+                        kind: DateTimeErrorKind::Overflow,
+                    })?,
+                DateTimeSevenPropertyModel {
+                    year: Some(1970),
+                    month: Some(1),
+                    day: Some(1),
+                    hour: Some(0),
+                    minute: Some(0),
+                    second: Some(Decimal::default()),
+                    timezone_offset: Some(TimezoneOffset::utc()),
+                },
+            )
+            .ok_or(DateTimeError {
+                kind: DateTimeErrorKind::Overflow,
+            })?,
+        )
+    }
+
+    fn from_le_bytes(bytes: [u8; 18]) -> Self {
+        let mut value = [0; 16];
+        value.copy_from_slice(&bytes[0..16]);
+        let mut timezone_offset = [0; 2];
+        timezone_offset.copy_from_slice(&bytes[16..18]);
+
+        Self {
+            value: Decimal::from_le_bytes(value),
+            timezone_offset: if timezone_offset == [u8::MAX; 2] {
+                None
+            } else {
+                Some(TimezoneOffset::from_le_bytes(timezone_offset))
+            },
+        }
+    }
+
+    fn year_month_day(&self) -> (i64, u8, u8) {
+        let mut days = (self.value.as_i128()
+            + i128::from(
+                self.timezone_offset
+                    .unwrap_or_else(TimezoneOffset::utc)
+                    .offset,
+            ) * 60)
+            .div_euclid(86400)
+            + 366;
+
+        // Make days positive
+        let shift = if days < 0 {
+            let shift = days / 146_097 - 1;
+            days -= shift * 146_097;
+            shift * 400
+        } else {
+            0
+        };
+
+        let year_mul_400 = days / 146_097;
+        days -= year_mul_400 * 146_097;
+
+        days -= 1;
+        let year_mul_100 = days / 36524;
+        days -= year_mul_100 * 36524;
+
+        days += 1;
+        let year_mul_4 = days / 1461;
+        days -= year_mul_4 * 1461;
+
+        days -= 1;
+        let year_mod_4 = days / 365;
+        days -= year_mod_4 * 365;
+
+        let year =
+            (400 * year_mul_400 + 100 * year_mul_100 + 4 * year_mul_4 + year_mod_4 + shift) as i64;
+
+        let leap_year_offset = if (year_mul_100 == 0 || year_mul_4 != 0) && year_mod_4 == 0 {
+            1
+        } else {
+            0
+        };
+        days += leap_year_offset;
+
+        let mut month = 0;
+        for month_i in 1..=12 {
+            let days_in_month = i128::from(days_in_month(Some(year), month_i));
+            if days_in_month > days {
+                month = month_i;
+                break;
+            }
+            days -= days_in_month
+        }
+        let day = days as u8 + 1;
+
+        (year, month, day)
+    }
+
+    fn year(&self) -> i64 {
+        let (year, _, _) = self.year_month_day();
+        year
+    }
+
+    fn month(&self) -> u8 {
+        let (_, month, _) = self.year_month_day();
+        month
+    }
+
+    fn day(&self) -> u8 {
+        let (_, _, day) = self.year_month_day();
+        day
+    }
+
+    fn hour(&self) -> u8 {
+        (((self.value.as_i128()
+            + i128::from(
+                self.timezone_offset
+                    .unwrap_or_else(TimezoneOffset::utc)
+                    .offset,
+            ) * 60)
+            .rem_euclid(86400))
+            / 3600) as u8
+    }
+
+    fn minute(&self) -> u8 {
+        (((self.value.as_i128()
+            + i128::from(
+                self.timezone_offset
+                    .unwrap_or_else(TimezoneOffset::utc)
+                    .offset,
+            ) * 60)
+            .rem_euclid(3600))
+            / 60) as u8
+    }
+
+    fn second(&self) -> Decimal {
+        self.value.checked_rem_euclid(60).unwrap().abs()
+    }
+
+    fn timezone_offset(&self) -> Option<TimezoneOffset> {
+        self.timezone_offset
+    }
+
+    fn checked_add_seconds(&self, seconds: Decimal) -> Option<Self> {
+        Some(Self {
+            value: self.value.checked_add(seconds)?,
+            timezone_offset: self.timezone_offset,
+        })
+    }
+
+    fn checked_sub(&self, rhs: Timestamp) -> Option<Duration> {
+        match (self.timezone_offset, rhs.timezone_offset) {
+            (Some(_), Some(_)) | (None, None) => {
+                Some(Duration::new(0, self.value.checked_sub(rhs.value)?))
+            }
+            _ => None, //TODO: implicit timezone
+        }
+    }
+
+    fn checked_sub_seconds(&self, seconds: Decimal) -> Option<Self> {
+        Some(Self {
+            value: self.value.checked_sub(seconds)?,
+            timezone_offset: self.timezone_offset,
+        })
+    }
+
+    fn to_le_bytes(&self) -> [u8; 18] {
+        let mut bytes = [0; 18];
+        bytes[0..16].copy_from_slice(&self.value.to_le_bytes());
+        bytes[16..18].copy_from_slice(&match &self.timezone_offset {
+            Some(timezone_offset) => timezone_offset.to_le_bytes(),
+            None => [u8::MAX; 2],
+        });
+        bytes
+    }
+}
+
+/// The [normalizeMonth](https://www.w3.org/TR/xmlschema11-2/#f-dt-normMo) function
+fn normalize_month(yr: i64, mo: i64) -> Option<(i64, u8)> {
+    if mo >= 0 {
+        let yr = yr.checked_add(mo.checked_sub(1)?.checked_div(12)?)?;
+        let mo = u8::try_from(mo.checked_sub(1)?.checked_rem(12)?.abs().checked_add(1)?).ok()?;
+        Some((yr, mo))
+    } else {
+        // Needed to make it work with negative durations
+        let yr = yr.checked_add(mo.checked_sub(1)?.checked_div(12)?.checked_sub(1)?)?;
+        let mo = u8::try_from(
+            12i64
+                .checked_add(mo.checked_sub(1)?.checked_rem(12)?)?
+                .checked_add(1)?,
+        )
+        .ok()?;
+        Some((yr, mo))
+    }
+}
+
+/// The [normalizeDa](https://www.w3.org/TR/xmlschema11-2/#f-dt-normDa) function
+fn normalize_day(yr: i64, mo: i64, mut da: i64) -> Option<(i64, u8, u8)> {
+    let (mut yr, mut mo) = normalize_month(yr, mo)?;
+    loop {
+        if da <= 0 {
+            let (yr2, mo2) = normalize_month(yr, i64::from(mo).checked_sub(1)?)?;
+            yr = yr2;
+            mo = mo2;
+            da = da.checked_add(days_in_month(Some(yr), mo).into())?;
+        } else if da > days_in_month(Some(yr), mo).into() {
+            da = da.checked_sub(days_in_month(Some(yr), mo).into())?;
+            let (yr2, mo2) = normalize_month(yr, i64::from(mo).checked_add(1)?)?;
+            yr = yr2;
+            mo = mo2;
+        } else {
+            return Some((yr, mo, u8::try_from(da).ok()?));
+        };
+    }
+}
+
+/// The [normalizeMinute](https://www.w3.org/TR/xmlschema11-2/#f-dt-normMi) function
+fn normalize_minute(yr: i64, mo: i64, da: i64, hr: i64, mi: i64) -> Option<(i64, u8, u8, u8, u8)> {
+    let hr = hr.checked_add(mi.checked_div(60)?)?;
+    let mi = mi.checked_rem(60)?;
+    let da = da.checked_add(hr.checked_div(24)?)?;
+    let hr = hr.checked_rem(24)?;
+    let (yr, mo, da) = normalize_day(yr, mo, da)?;
+    Some((yr, mo, da, u8::try_from(hr).ok()?, u8::try_from(mi).ok()?))
+}
+
+/// The [normalizeSecond](https://www.w3.org/TR/xmlschema11-2/#f-dt-normSe) function
+fn normalize_second(
+    yr: i64,
+    mo: i64,
+    da: i64,
+    hr: i64,
+    mi: i64,
+    se: Decimal,
+) -> Option<(i64, u8, u8, u8, u8, Decimal)> {
+    let mi = mi.checked_add(i64::try_from(se.as_i128().checked_div(60)?).ok()?)?; //TODO: good idea?
+    let se = se.checked_rem(60)?;
+    let (yr, mo, da, hr, mi) = normalize_minute(yr, mo, da, hr, mi)?;
+    Some((yr, mo, da, hr, mi, se))
+}
+
+/// The [daysInMonth](https://www.w3.org/TR/xmlschema11-2/#f-daysInMonth) function
+fn days_in_month(y: Option<i64>, m: u8) -> u8 {
+    match m {
+        2 => {
+            if let Some(y) = y {
+                if y % 4 != 0 || (y % 100 == 0 && y % 400 != 0) {
+                    28
+                } else {
+                    29
+                }
+            } else {
+                28
+            }
+        }
+        4 | 6 | 9 | 11 => 30,
+        _ => 31,
+    }
+}
+
+/// The [dateTimePlusDuration](https://www.w3.org/TR/xmlschema11-2/#vp-dt-dateTimePlusDuration) function
+fn date_time_plus_duration(
+    du: Duration,
+    dt: DateTimeSevenPropertyModel,
+) -> Option<DateTimeSevenPropertyModel> {
+    let yr = dt.year.unwrap_or(1);
+    let mo = dt.month.unwrap_or(1);
+    let da = dt.day.unwrap_or(1);
+    let hr = dt.hour.unwrap_or(0);
+    let mi = dt.minute.unwrap_or(0);
+    let se = dt.second.unwrap_or_else(Decimal::default);
+    let mo = i64::from(mo).checked_add(du.all_months())?;
+    let (yr, mo) = normalize_month(yr, mo)?;
+    let da = min(da, days_in_month(Some(yr), mo));
+    let se = se.checked_add(du.all_seconds())?;
+    let (yr, mo, da, hr, mi, se) =
+        normalize_second(yr, mo.into(), da.into(), hr.into(), mi.into(), se)?;
+
+    Some(DateTimeSevenPropertyModel {
+        year: dt.year.map(|_| yr),
+        month: dt.month.map(|_| mo),
+        day: dt.day.map(|_| da),
+        hour: dt.hour.map(|_| hr),
+        minute: dt.minute.map(|_| mi),
+        second: dt.second.map(|_| se),
+        timezone_offset: dt.timezone_offset,
+    })
+}
+
+/// The [timeOnTimeline](https://www.w3.org/TR/xmlschema11-2/#vp-dt-timeOnTimeline) function
+fn time_on_timeline(props: DateTimeSevenPropertyModel) -> Option<Decimal> {
+    let yr = props.year.map_or(1971, |y| y - 1);
+    let mo = props.month.unwrap_or(12);
+    let da = props
+        .day
+        .map_or_else(|| days_in_month(Some(yr + 1), mo) - 1, |d| d - 1);
+    let hr = props.hour.unwrap_or(0);
+    let mi = i128::from(props.minute.unwrap_or(0))
+        - i128::from(
+            props
+                .timezone_offset
+                .unwrap_or_else(TimezoneOffset::utc)
+                .offset,
+        );
+    let se = props.second.unwrap_or_else(Decimal::default);
+
+    Decimal::try_from(
+        31_536_000 * i128::from(yr)
+            + 86400 * i128::from(yr.div_euclid(400) - yr.div_euclid(100) + yr.div_euclid(4))
+            + 86400
+                * (1..mo)
+                    .map(|m| i128::from(days_in_month(Some(yr + 1), m)))
+                    .sum::<i128>()
+            + 86400 * i128::from(da)
+            + 3600 * i128::from(hr)
+            + 60 * mi,
+    )
+    .ok()?
+    .checked_add(se)
+}
+
+#[derive(Debug, Clone)]
+pub struct DateTimeError {
+    kind: DateTimeErrorKind,
+}
+
+#[derive(Debug, Clone)]
+enum DateTimeErrorKind {
+    InvalidDayOfMonth { day: u8, month: u8 },
+    Overflow,
+    SystemTime(SystemTimeError),
+}
+
+impl fmt::Display for DateTimeError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match &self.kind {
+            DateTimeErrorKind::InvalidDayOfMonth { day, month } => {
+                write!(f, "{} is not a valid day of {}", day, month)
+            }
+            DateTimeErrorKind::Overflow => write!(f, "Overflow during date time normalization"),
+            DateTimeErrorKind::SystemTime(error) => error.fmt(f),
+        }
+    }
+}
+
+impl Error for DateTimeError {
+    fn source(&self) -> Option<&(dyn Error + 'static)> {
+        match &self.kind {
+            DateTimeErrorKind::SystemTime(error) => Some(error),
+            _ => None,
+        }
+    }
+}
+
+impl From<SystemTimeError> for DateTimeError {
+    fn from(error: SystemTimeError) -> Self {
+        Self {
+            kind: DateTimeErrorKind::SystemTime(error),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn from_str() {
+        assert_eq!(
+            Time::from_str("00:00:00Z").unwrap().to_string(),
+            "00:00:00Z"
+        );
+        assert_eq!(Time::from_str("00:00:00").unwrap().to_string(), "00:00:00");
+        assert_eq!(
+            Time::from_str("00:00:00+02:00").unwrap().to_string(),
+            "00:00:00+02:00"
+        );
+        assert_eq!(
+            Time::from_str("00:00:00+14:00").unwrap().to_string(),
+            "00:00:00+14:00"
+        );
+        assert_eq!(Time::from_str("24:00:00").unwrap().to_string(), "00:00:00");
+        assert_eq!(
+            Time::from_str("24:00:00.00").unwrap().to_string(),
+            "00:00:00"
+        );
+        assert_eq!(
+            Time::from_str("23:59:59.9999999999").unwrap().to_string(),
+            "23:59:59.9999999999"
+        );
+
+        assert_eq!(
+            Date::from_str("0001-01-01Z").unwrap().to_string(),
+            "0001-01-01Z"
+        );
+        assert_eq!(
+            Date::from_str("0001-01-01").unwrap().to_string(),
+            "0001-01-01"
+        );
+        assert_eq!(
+            DateTime::from_str("0001-01-01T00:00:00Z")
+                .unwrap()
+                .to_string(),
+            "0001-01-01T00:00:00Z"
+        );
+        assert_eq!(
+            DateTime::from_str("0001-01-01T00:00:00")
+                .unwrap()
+                .to_string(),
+            "0001-01-01T00:00:00"
+        );
+        assert_eq!(
+            DateTime::from_str("1000000000-01-01T00:00:00")
+                .unwrap()
+                .to_string(),
+            "1000000000-01-01T00:00:00"
+        );
+        assert_eq!(
+            DateTime::from_str("2001-12-31T23:59:59")
+                .unwrap()
+                .to_string(),
+            "2001-12-31T23:59:59"
+        );
+        assert_eq!(
+            DateTime::from_str("2004-12-31T23:59:59")
+                .unwrap()
+                .to_string(),
+            "2004-12-31T23:59:59"
+        );
+        assert_eq!(
+            DateTime::from_str("1900-12-31T23:59:59")
+                .unwrap()
+                .to_string(),
+            "1900-12-31T23:59:59"
+        );
+        assert_eq!(
+            DateTime::from_str("2000-12-31T23:59:59")
+                .unwrap()
+                .to_string(),
+            "2000-12-31T23:59:59",
+        );
+        assert_eq!(
+            DateTime::from_str("1899-12-31T23:59:59")
+                .unwrap()
+                .to_string(),
+            "1899-12-31T23:59:59"
+        );
+
+        assert_eq!(
+            DateTime::from_str("2001-02-28T23:59:59")
+                .unwrap()
+                .to_string(),
+            "2001-02-28T23:59:59"
+        );
+        assert_eq!(
+            DateTime::from_str("2004-02-29T23:59:59")
+                .unwrap()
+                .to_string(),
+            "2004-02-29T23:59:59"
+        );
+        assert_eq!(
+            DateTime::from_str("1900-02-28T23:59:59")
+                .unwrap()
+                .to_string(),
+            "1900-02-28T23:59:59"
+        );
+        assert_eq!(
+            DateTime::from_str("2000-02-29T23:59:59")
+                .unwrap()
+                .to_string(),
+            "2000-02-29T23:59:59",
+        );
+        assert_eq!(
+            DateTime::from_str("1899-02-28T23:59:59")
+                .unwrap()
+                .to_string(),
+            "1899-02-28T23:59:59"
+        );
+        assert_eq!(
+            DateTime::from_str("2001-03-01T00:00:00")
+                .unwrap()
+                .to_string(),
+            "2001-03-01T00:00:00"
+        );
+        assert_eq!(
+            DateTime::from_str("2004-03-01T00:00:00")
+                .unwrap()
+                .to_string(),
+            "2004-03-01T00:00:00"
+        );
+        assert_eq!(
+            DateTime::from_str("1900-03-01T00:00:00")
+                .unwrap()
+                .to_string(),
+            "1900-03-01T00:00:00"
+        );
+        assert_eq!(
+            DateTime::from_str("2000-03-01T00:00:00")
+                .unwrap()
+                .to_string(),
+            "2000-03-01T00:00:00",
+        );
+        assert_eq!(
+            DateTime::from_str("1899-03-01T00:00:00")
+                .unwrap()
+                .to_string(),
+            "1899-03-01T00:00:00"
+        );
+
+        /*TODO assert_eq!(
+            DateTime::from_str("-1000000000-01-01T00:00:00")
+                .unwrap()
+                .to_string(),
+            "-1000000000-01-01T00:00:00"
+        );*/
+        assert_eq!(
+            DateTime::from_str("-2001-12-31T23:59:59")
+                .unwrap()
+                .to_string(),
+            "-2001-12-31T23:59:59"
+        );
+        assert_eq!(
+            DateTime::from_str("-2004-12-31T23:59:59")
+                .unwrap()
+                .to_string(),
+            "-2004-12-31T23:59:59"
+        );
+        assert_eq!(
+            DateTime::from_str("-1900-12-31T23:59:59")
+                .unwrap()
+                .to_string(),
+            "-1900-12-31T23:59:59"
+        );
+        assert_eq!(
+            DateTime::from_str("-2000-12-31T23:59:59")
+                .unwrap()
+                .to_string(),
+            "-2000-12-31T23:59:59"
+        );
+        assert_eq!(
+            DateTime::from_str("-1899-12-31T23:59:59")
+                .unwrap()
+                .to_string(),
+            "-1899-12-31T23:59:59"
+        );
+    }
+
+    #[test]
+    fn equals() {
+        assert_eq!(
+            DateTime::from_str("2002-04-02T12:00:00-01:00").unwrap(),
+            DateTime::from_str("2002-04-02T17:00:00+04:00").unwrap()
+        );
+        assert_eq!(
+            DateTime::from_str("2002-04-02T12:00:00-05:00").unwrap(),
+            DateTime::from_str("2002-04-02T23:00:00+06:00").unwrap()
+        );
+        assert_ne!(
+            DateTime::from_str("2002-04-02T12:00:00-05:00").unwrap(),
+            DateTime::from_str("2002-04-02T17:00:00-05:00").unwrap()
+        );
+        assert_eq!(
+            DateTime::from_str("2002-04-02T12:00:00-05:00").unwrap(),
+            DateTime::from_str("2002-04-02T12:00:00-05:00").unwrap()
+        );
+        assert_eq!(
+            DateTime::from_str("2002-04-02T23:00:00-04:00").unwrap(),
+            DateTime::from_str("2002-04-03T02:00:00-01:00").unwrap()
+        );
+        assert_eq!(
+            DateTime::from_str("1999-12-31T24:00:00-05:00").unwrap(),
+            DateTime::from_str("2000-01-01T00:00:00-05:00").unwrap()
+        );
+        assert_ne!(
+            DateTime::from_str("2005-04-04T24:00:00-05:00").unwrap(),
+            DateTime::from_str("2005-04-04T00:00:00-05:00").unwrap()
+        );
+
+        assert_ne!(
+            Date::from_str("2004-12-25Z").unwrap(),
+            Date::from_str("2004-12-25+07:00").unwrap()
+        );
+        assert_eq!(
+            Date::from_str("2004-12-25-12:00").unwrap(),
+            Date::from_str("2004-12-26+12:00").unwrap()
+        );
+
+        assert_ne!(
+            Time::from_str("08:00:00+09:00").unwrap(),
+            Time::from_str("17:00:00-06:00").unwrap()
+        );
+        assert_eq!(
+            Time::from_str("21:30:00+10:30").unwrap(),
+            Time::from_str("06:00:00-05:00").unwrap()
+        );
+        assert_eq!(
+            Time::from_str("24:00:00+01:00").unwrap(),
+            Time::from_str("00:00:00+01:00").unwrap()
+        );
+
+        assert_eq!(
+            Time::from_str("05:00:00-03:00").unwrap(),
+            Time::from_str("10:00:00+02:00").unwrap()
+        );
+        assert_ne!(
+            Time::from_str("23:00:00-03:00").unwrap(),
+            Time::from_str("02:00:00Z").unwrap()
+        );
+    }
+
+    #[test]
+    fn cmp() {
+        assert!(
+            Date::from_str("2004-12-25Z").unwrap() < Date::from_str("2004-12-25-05:00").unwrap()
+        );
+        assert!(
+            !(Date::from_str("2004-12-25-12:00").unwrap()
+                < Date::from_str("2004-12-26+12:00").unwrap())
+        );
+
+        assert!(
+            Date::from_str("2004-12-25Z").unwrap() > Date::from_str("2004-12-25+07:00").unwrap()
+        );
+        assert!(
+            !(Date::from_str("2004-12-25-12:00").unwrap()
+                > Date::from_str("2004-12-26+12:00").unwrap())
+        );
+
+        assert!(!(Time::from_str("12:00:00").unwrap() < Time::from_str("23:00:00+06:00").unwrap()));
+        assert!(Time::from_str("11:00:00-05:00").unwrap() < Time::from_str("17:00:00Z").unwrap());
+        assert!(!(Time::from_str("23:59:59").unwrap() < Time::from_str("24:00:00").unwrap()));
+
+        assert!(
+            !(Time::from_str("08:00:00+09:00").unwrap()
+                > Time::from_str("17:00:00-06:00").unwrap())
+        );
+    }
+
+    #[test]
+    fn year() {
+        assert_eq!(
+            DateTime::from_str("1999-05-31T13:20:00-05:00")
+                .unwrap()
+                .year(),
+            1999
+        );
+        assert_eq!(
+            DateTime::from_str("1999-05-31T21:30:00-05:00")
+                .unwrap()
+                .year(),
+            1999
+        );
+        assert_eq!(
+            DateTime::from_str("1999-12-31T19:20:00").unwrap().year(),
+            1999
+        );
+        assert_eq!(
+            DateTime::from_str("1999-12-31T24:00:00").unwrap().year(),
+            2000
+        );
+        assert_eq!(
+            DateTime::from_str("-0002-06-06T00:00:00").unwrap().year(),
+            -2
+        );
+
+        assert_eq!(Date::from_str("1999-05-31").unwrap().year(), 1999);
+        assert_eq!(Date::from_str("2000-01-01+05:00").unwrap().year(), 2000);
+        assert_eq!(Date::from_str("-0002-06-01").unwrap().year(), -2);
+    }
+
+    #[test]
+    fn month() {
+        assert_eq!(
+            DateTime::from_str("1999-05-31T13:20:00-05:00")
+                .unwrap()
+                .month(),
+            5
+        );
+        assert_eq!(
+            DateTime::from_str("1999-12-31T19:20:00-05:00")
+                .unwrap()
+                .month(),
+            12
+        );
+
+        assert_eq!(Date::from_str("1999-05-31-05:00").unwrap().month(), 5);
+        assert_eq!(Date::from_str("2000-01-01+05:00").unwrap().month(), 1);
+    }
+
+    #[test]
+    fn day() {
+        assert_eq!(
+            DateTime::from_str("1999-05-31T13:20:00-05:00")
+                .unwrap()
+                .day(),
+            31
+        );
+        assert_eq!(
+            DateTime::from_str("1999-12-31T20:00:00-05:00")
+                .unwrap()
+                .day(),
+            31
+        );
+
+        assert_eq!(Date::from_str("1999-05-31-05:00").unwrap().day(), 31);
+        assert_eq!(Date::from_str("2000-01-01+05:00").unwrap().day(), 1);
+    }
+
+    #[test]
+    fn hour() {
+        assert_eq!(
+            DateTime::from_str("1999-05-31T08:20:00-05:00")
+                .unwrap()
+                .hour(),
+            8
+        );
+        assert_eq!(
+            DateTime::from_str("1999-12-31T21:20:00-05:00")
+                .unwrap()
+                .hour(),
+            21
+        );
+        assert_eq!(
+            DateTime::from_str("1999-12-31T12:00:00").unwrap().hour(),
+            12
+        );
+        assert_eq!(DateTime::from_str("1999-12-31T24:00:00").unwrap().hour(), 0);
+
+        assert_eq!(Time::from_str("11:23:00-05:00").unwrap().hour(), 11);
+        assert_eq!(Time::from_str("21:23:00-05:00").unwrap().hour(), 21);
+        assert_eq!(Time::from_str("01:23:00+05:00").unwrap().hour(), 1);
+        assert_eq!(Time::from_str("24:00:00").unwrap().hour(), 0);
+    }
+
+    #[test]
+    fn minute() {
+        assert_eq!(
+            DateTime::from_str("1999-05-31T13:20:00-05:00")
+                .unwrap()
+                .minute(),
+            20
+        );
+        assert_eq!(
+            DateTime::from_str("1999-05-31T13:30:00+05:30")
+                .unwrap()
+                .minute(),
+            30
+        );
+
+        assert_eq!(Time::from_str("13:00:00Z").unwrap().minute(), 0);
+    }
+
+    #[test]
+    fn second() {
+        assert_eq!(
+            DateTime::from_str("1999-05-31T13:20:00-05:00")
+                .unwrap()
+                .second(),
+            Decimal::from(0)
+        );
+
+        assert_eq!(
+            Time::from_str("13:20:10.5").unwrap().second(),
+            Decimal::from_str("10.5").unwrap()
+        );
+    }
+
+    #[test]
+    fn timezone() {
+        assert_eq!(
+            DateTime::from_str("1999-05-31T13:20:00-05:00")
+                .unwrap()
+                .timezone(),
+            Some(Duration::from_str("-PT5H").unwrap())
+        );
+        assert_eq!(
+            DateTime::from_str("2000-06-12T13:20:00Z")
+                .unwrap()
+                .timezone(),
+            Some(Duration::from_str("PT0S").unwrap())
+        );
+        assert_eq!(
+            DateTime::from_str("2004-08-27T00:00:00")
+                .unwrap()
+                .timezone(),
+            None
+        );
+
+        assert_eq!(
+            Date::from_str("1999-05-31-05:00").unwrap().timezone(),
+            Some(Duration::from_str("-PT5H").unwrap())
+        );
+        assert_eq!(
+            Date::from_str("2000-06-12Z").unwrap().timezone(),
+            Some(Duration::from_str("PT0S").unwrap())
+        );
+
+        assert_eq!(
+            Time::from_str("13:20:00-05:00").unwrap().timezone(),
+            Some(Duration::from_str("-PT5H").unwrap())
+        );
+        assert_eq!(Time::from_str("13:20:00").unwrap().timezone(), None);
+    }
+
+    #[test]
+    fn sub() {
+        assert_eq!(
+            DateTime::from_str("2000-10-30T06:12:00-05:00")
+                .unwrap()
+                .checked_sub(DateTime::from_str("1999-11-28T09:00:00Z").unwrap())
+                .unwrap(),
+            Duration::from_str("P337DT2H12M").unwrap()
+        );
+
+        assert_eq!(
+            Date::from_str("2000-10-30")
+                .unwrap()
+                .checked_sub(Date::from_str("1999-11-28").unwrap())
+                .unwrap(),
+            Duration::from_str("P337D").unwrap()
+        );
+        assert_eq!(
+            Date::from_str("2000-10-30+05:00")
+                .unwrap()
+                .checked_sub(Date::from_str("1999-11-28Z").unwrap())
+                .unwrap(),
+            Duration::from_str("P336DT19H").unwrap()
+        );
+        assert_eq!(
+            Date::from_str("2000-10-15-05:00")
+                .unwrap()
+                .checked_sub(Date::from_str("2000-10-10+02:00").unwrap())
+                .unwrap(),
+            Duration::from_str("P5DT7H").unwrap()
+        );
+
+        assert_eq!(
+            Time::from_str("11:12:00Z")
+                .unwrap()
+                .checked_sub(Time::from_str("04:00:00-05:00").unwrap())
+                .unwrap(),
+            Duration::from_str("PT2H12M").unwrap()
+        );
+        assert_eq!(
+            Time::from_str("11:00:00-05:00")
+                .unwrap()
+                .checked_sub(Time::from_str("21:30:00+05:30").unwrap())
+                .unwrap(),
+            Duration::from_str("PT0S").unwrap()
+        );
+        assert_eq!(
+            Time::from_str("17:00:00-06:00")
+                .unwrap()
+                .checked_sub(Time::from_str("08:00:00+09:00").unwrap())
+                .unwrap(),
+            Duration::from_str("P1D").unwrap()
+        );
+        assert_eq!(
+            Time::from_str("24:00:00")
+                .unwrap()
+                .checked_sub(Time::from_str("23:59:59").unwrap())
+                .unwrap(),
+            Duration::from_str("-PT23H59M59S").unwrap()
+        );
+    }
+
+    #[test]
+    fn add_duration() {
+        assert_eq!(
+            DateTime::from_str("2000-01-12T12:13:14Z")
+                .unwrap()
+                .checked_add_duration(Duration::from_str("P1Y3M5DT7H10M3.3S").unwrap())
+                .unwrap(),
+            DateTime::from_str("2001-04-17T19:23:17.3Z").unwrap()
+        );
+        assert_eq!(
+            Date::from_str("2000-01-01")
+                .unwrap()
+                .checked_add_duration(Duration::from_str("-P3M").unwrap())
+                .unwrap()
+                .to_string(),
+            "1999-10-01"
+        );
+        assert_eq!(
+            Date::from_str("2000-01-12")
+                .unwrap()
+                .checked_add_duration(Duration::from_str("PT33H").unwrap())
+                .unwrap(),
+            Date::from_str("2000-01-13").unwrap()
+        );
+        assert_eq!(
+            Date::from_str("2000-03-30")
+                .unwrap()
+                .checked_add_duration(Duration::from_str("P1D").unwrap())
+                .unwrap(),
+            Date::from_str("2000-03-31").unwrap()
+        );
+        assert_eq!(
+            Date::from_str("2000-03-31")
+                .unwrap()
+                .checked_add_duration(Duration::from_str("P1M").unwrap())
+                .unwrap(),
+            Date::from_str("2000-04-30").unwrap()
+        );
+        assert_eq!(
+            Date::from_str("2000-03-30")
+                .unwrap()
+                .checked_add_duration(Duration::from_str("P1M").unwrap())
+                .unwrap(),
+            Date::from_str("2000-04-30").unwrap()
+        );
+        assert_eq!(
+            Date::from_str("2000-04-30")
+                .unwrap()
+                .checked_add_duration(Duration::from_str("P1D").unwrap())
+                .unwrap(),
+            Date::from_str("2000-05-01").unwrap()
+        );
+
+        assert_eq!(
+            DateTime::from_str("2000-10-30T11:12:00")
+                .unwrap()
+                .checked_add_duration(Duration::from_str("P1Y2M").unwrap())
+                .unwrap(),
+            DateTime::from_str("2001-12-30T11:12:00").unwrap()
+        );
+        assert_eq!(
+            DateTime::from_str("2000-10-30T11:12:00")
+                .unwrap()
+                .checked_add_duration(Duration::from_str("P3DT1H15M").unwrap())
+                .unwrap(),
+            DateTime::from_str("2000-11-02T12:27:00").unwrap()
+        );
+
+        assert_eq!(
+            Date::from_str("2000-10-30")
+                .unwrap()
+                .checked_add_duration(Duration::from_str("P1Y2M").unwrap())
+                .unwrap(),
+            Date::from_str("2001-12-30").unwrap()
+        );
+        assert_eq!(
+            Date::from_str("2004-10-30Z")
+                .unwrap()
+                .checked_add_duration(Duration::from_str("P2DT2H30M0S").unwrap())
+                .unwrap(),
+            Date::from_str("2004-11-01Z").unwrap()
+        );
+
+        assert_eq!(
+            Time::from_str("11:12:00")
+                .unwrap()
+                .checked_add_duration(Duration::from_str("P3DT1H15M").unwrap())
+                .unwrap(),
+            Time::from_str("12:27:00").unwrap()
+        );
+        assert_eq!(
+            Time::from_str("23:12:00+03:00")
+                .unwrap()
+                .checked_add_duration(Duration::from_str("P1DT3H15M").unwrap())
+                .unwrap(),
+            Time::from_str("02:27:00+03:00").unwrap()
+        );
+    }
+
+    #[test]
+    fn sub_duration() {
+        assert_eq!(
+            DateTime::from_str("2000-10-30T11:12:00")
+                .unwrap()
+                .checked_sub_duration(Duration::from_str("P1Y2M").unwrap())
+                .unwrap(),
+            DateTime::from_str("1999-08-30T11:12:00").unwrap()
+        );
+        assert_eq!(
+            DateTime::from_str("2000-10-30T11:12:00")
+                .unwrap()
+                .checked_sub_duration(Duration::from_str("P3DT1H15M").unwrap())
+                .unwrap(),
+            DateTime::from_str("2000-10-27T09:57:00").unwrap()
+        );
+
+        assert_eq!(
+            Date::from_str("2000-10-30")
+                .unwrap()
+                .checked_sub_duration(Duration::from_str("P1Y2M").unwrap())
+                .unwrap(),
+            Date::from_str("1999-08-30").unwrap()
+        );
+        assert_eq!(
+            Date::from_str("2000-02-29Z")
+                .unwrap()
+                .checked_sub_duration(Duration::from_str("P1Y").unwrap())
+                .unwrap(),
+            Date::from_str("1999-02-28Z").unwrap()
+        );
+        assert_eq!(
+            Date::from_str("2000-10-31-05:00")
+                .unwrap()
+                .checked_sub_duration(Duration::from_str("P1Y1M").unwrap())
+                .unwrap(),
+            Date::from_str("1999-09-30-05:00").unwrap()
+        );
+        assert_eq!(
+            Date::from_str("2000-10-30")
+                .unwrap()
+                .checked_sub_duration(Duration::from_str("P3DT1H15M").unwrap())
+                .unwrap(),
+            Date::from_str("2000-10-26").unwrap()
+        );
+
+        assert_eq!(
+            Time::from_str("11:12:00")
+                .unwrap()
+                .checked_sub_duration(Duration::from_str("P3DT1H15M").unwrap())
+                .unwrap(),
+            Time::from_str("09:57:00").unwrap()
+        );
+        assert_eq!(
+            Time::from_str("08:20:00-05:00")
+                .unwrap()
+                .checked_sub_duration(Duration::from_str("P23DT10H10M").unwrap())
+                .unwrap(),
+            Time::from_str("22:10:00-05:00").unwrap()
+        );
+    }
+}
diff --git a/lib/src/model/xsd/decimal.rs b/lib/src/model/xsd/decimal.rs
index 2517a62a..35404a4e 100644
--- a/lib/src/model/xsd/decimal.rs
+++ b/lib/src/model/xsd/decimal.rs
@@ -2,6 +2,7 @@ use std::convert::{TryFrom, TryInto};
 use std::error::Error;
 use std::fmt;
 use std::fmt::Write;
+use std::i128;
 use std::ops::Neg;
 use std::str::FromStr;
 
@@ -10,6 +11,13 @@ const DECIMAL_PART_POW: i128 = 1_000_000_000_000_000_000;
 const DECIMAL_PART_POW_MINUS_ONE: i128 = 100_000_000_000_000_000;
 const DECIMAL_PART_HALF_POW: i128 = 1_000_000_000;
 
+#[cfg(test)]
+pub(super) const MIN: Decimal = Decimal { value: i128::MIN };
+#[cfg(test)]
+pub(super) const MAX: Decimal = Decimal { value: i128::MAX };
+#[cfg(test)]
+pub(super) const STEP: Decimal = Decimal { value: 1 };
+
 /// [XML Schema `decimal` datatype](https://www.w3.org/TR/xmlschema11-2/#decimal) implementation.
 ///
 /// It stores the decimal in a fix point encoding allowing nearly 18 digits before and 18 digits after ".".
@@ -19,6 +27,17 @@ pub struct Decimal {
 }
 
 impl Decimal {
+    /// Constructs the decimal i / 10^n
+    pub fn new(i: i128, n: u32) -> Result<Self, DecimalOverflowError> {
+        if n > DECIMAL_PART_DIGITS as u32 {
+            //TODO: check if end with zeros?
+            return Err(DecimalOverflowError);
+        }
+        Ok(Self {
+            value: i.checked_div(10i128.pow(n)).ok_or(DecimalOverflowError)?,
+        })
+    }
+
     #[inline]
     pub fn from_le_bytes(bytes: [u8; 16]) -> Self {
         Self {
@@ -27,15 +46,88 @@ impl Decimal {
     }
 }
 
-impl<I: Into<i64>> From<I> for Decimal {
+impl From<i8> for Decimal {
     #[inline]
-    fn from(value: I) -> Self {
-        let value: i64 = value.into();
+    fn from(value: i8) -> Self {
+        Self {
+            value: i128::from(value) * DECIMAL_PART_POW,
+        }
+    }
+}
+impl From<i16> for Decimal {
+    fn from(value: i16) -> Self {
+        Self {
+            value: i128::from(value) * DECIMAL_PART_POW,
+        }
+    }
+}
+impl From<i32> for Decimal {
+    fn from(value: i32) -> Self {
+        Self {
+            value: i128::from(value) * DECIMAL_PART_POW,
+        }
+    }
+}
+impl From<i64> for Decimal {
+    fn from(value: i64) -> Self {
         Self {
             value: i128::from(value) * DECIMAL_PART_POW,
         }
     }
 }
+impl From<u8> for Decimal {
+    fn from(value: u8) -> Self {
+        Self {
+            value: i128::from(value) * DECIMAL_PART_POW,
+        }
+    }
+}
+impl From<u16> for Decimal {
+    fn from(value: u16) -> Self {
+        Self {
+            value: i128::from(value) * DECIMAL_PART_POW,
+        }
+    }
+}
+impl From<u32> for Decimal {
+    fn from(value: u32) -> Self {
+        Self {
+            value: i128::from(value) * DECIMAL_PART_POW,
+        }
+    }
+}
+impl From<u64> for Decimal {
+    fn from(value: u64) -> Self {
+        Self {
+            value: i128::from(value) * DECIMAL_PART_POW,
+        }
+    }
+}
+
+impl TryFrom<i128> for Decimal {
+    type Error = DecimalOverflowError;
+
+    fn try_from(value: i128) -> Result<Self, DecimalOverflowError> {
+        Ok(Self {
+            value: value
+                .checked_mul(DECIMAL_PART_POW)
+                .ok_or(DecimalOverflowError)?,
+        })
+    }
+}
+
+impl TryFrom<u128> for Decimal {
+    type Error = DecimalOverflowError;
+
+    fn try_from(value: u128) -> Result<Self, DecimalOverflowError> {
+        Ok(Self {
+            value: i128::try_from(value)
+                .map_err(|_| DecimalOverflowError)?
+                .checked_mul(DECIMAL_PART_POW)
+                .ok_or(DecimalOverflowError)?,
+        })
+    }
+}
 
 impl FromStr for Decimal {
     type Err = ParseDecimalError;
@@ -146,11 +238,41 @@ impl fmt::Display for ParseDecimalError {
 
 impl Error for ParseDecimalError {}
 
+impl From<DecimalOverflowError> for ParseDecimalError {
+    fn from(_: DecimalOverflowError) -> Self {
+        Self {
+            kind: ParseDecimalErrorKind::Overflow,
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct DecimalOverflowError;
+
+impl fmt::Display for DecimalOverflowError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "Value overflow")
+    }
+}
+
+impl Error for DecimalOverflowError {}
+
 impl fmt::Display for Decimal {
     /// Formats the decimal following its canonical representation
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        if self.value == 0 {
+            return if let Some(width) = f.width() {
+                for _ in 0..width {
+                    f.write_char('0')?;
+                }
+                Ok(())
+            } else {
+                f.write_char('0')
+            };
+        }
+
         let mut value = self.value;
-        if value < 0 {
+        if self.value.is_negative() {
             f.write_char('-')?;
         }
 
@@ -162,10 +284,6 @@ impl fmt::Display for Decimal {
             i += 1;
         }
 
-        if i == 0 {
-            return f.write_char('0');
-        }
-
         let last_non_zero = i - 1;
         let first_non_zero = digits
             .iter()
@@ -176,7 +294,19 @@ impl fmt::Display for Decimal {
             .unwrap_or(40);
 
         if last_non_zero >= DECIMAL_PART_DIGITS {
-            for c in digits[DECIMAL_PART_DIGITS..=last_non_zero].iter().rev() {
+            let end = if let Some(mut width) = f.width() {
+                if self.value.is_negative() {
+                    width -= 1;
+                }
+                if last_non_zero - DECIMAL_PART_DIGITS + 1 < width {
+                    DECIMAL_PART_DIGITS + width
+                } else {
+                    last_non_zero + 1
+                }
+            } else {
+                last_non_zero + 1
+            };
+            for c in digits[DECIMAL_PART_DIGITS..end].iter().rev() {
                 f.write_char(char::from(*c))?;
             }
         } else {
@@ -184,7 +314,16 @@ impl fmt::Display for Decimal {
         }
         if DECIMAL_PART_DIGITS > first_non_zero {
             f.write_char('.')?;
-            for c in digits[first_non_zero..DECIMAL_PART_DIGITS].iter().rev() {
+            let start = if let Some(precision) = f.precision() {
+                if DECIMAL_PART_DIGITS - first_non_zero > precision {
+                    DECIMAL_PART_DIGITS - precision
+                } else {
+                    first_non_zero
+                }
+            } else {
+                first_non_zero
+            };
+            for c in digits[start..DECIMAL_PART_DIGITS].iter().rev() {
                 f.write_char(char::from(*c))?;
             }
         }
@@ -205,56 +344,64 @@ impl Neg for Decimal {
 }
 
 impl Decimal {
-    /*pub fn trunc(self) -> i64 {
-        (self.value / DECIMAL_PART_POW) as i64
-    }*/
-
-    #[inline]
     pub fn to_le_bytes(&self) -> [u8; 16] {
         self.value.to_le_bytes()
     }
 
     /// [op:numeric-add](https://www.w3.org/TR/xpath-functions/#func-numeric-add)
     #[inline]
-    pub fn checked_add(&self, rhs: Self) -> Option<Self> {
+    pub fn checked_add(&self, rhs: impl Into<Self>) -> Option<Self> {
         Some(Self {
-            value: self.value.checked_add(rhs.value)?,
+            value: self.value.checked_add(rhs.into().value)?,
         })
     }
 
     /// [op:numeric-subtract](https://www.w3.org/TR/xpath-functions/#func-numeric-subtract)
     #[inline]
-    pub fn checked_sub(&self, rhs: Self) -> Option<Self> {
+    pub fn checked_sub(&self, rhs: impl Into<Self>) -> Option<Self> {
         Some(Self {
-            value: self.value.checked_sub(rhs.value)?,
+            value: self.value.checked_sub(rhs.into().value)?,
         })
     }
 
     /// [op:numeric-multiply](https://www.w3.org/TR/xpath-functions/#func-numeric-multiply)
     #[inline]
-    pub fn checked_mul(&self, rhs: Self) -> Option<Self> {
+    pub fn checked_mul(&self, rhs: impl Into<Self>) -> Option<Self> {
         //TODO: better algorithm to keep precision
         Some(Self {
             value: self
                 .value
                 .checked_div(DECIMAL_PART_HALF_POW)?
-                .checked_mul(rhs.value.checked_div(DECIMAL_PART_HALF_POW)?)?,
+                .checked_mul(rhs.into().value.checked_div(DECIMAL_PART_HALF_POW)?)?,
         })
     }
 
     /// [op:numeric-divide](https://www.w3.org/TR/xpath-functions/#func-numeric-divide)
     #[inline]
-    pub fn checked_div(&self, rhs: Self) -> Option<Self> {
+    pub fn checked_div(&self, rhs: impl Into<Self>) -> Option<Self> {
         //TODO: better algorithm to keep precision
         Some(Self {
             value: self
                 .value
                 .checked_mul(DECIMAL_PART_HALF_POW)?
-                .checked_div(rhs.value)?
+                .checked_div(rhs.into().value)?
                 .checked_mul(DECIMAL_PART_HALF_POW)?,
         })
     }
 
+    /// TODO: XSD? is well defined for not integer
+    pub fn checked_rem(&self, rhs: impl Into<Self>) -> Option<Self> {
+        Some(Self {
+            value: self.value.checked_rem(rhs.into().value)?,
+        })
+    }
+
+    pub fn checked_rem_euclid(&self, rhs: impl Into<Self>) -> Option<Self> {
+        Some(Self {
+            value: self.value.checked_rem_euclid(rhs.into().value)?,
+        })
+    }
+
     /// [fn:abs](https://www.w3.org/TR/xpath-functions/#func-abs)
     #[inline]
     pub fn abs(&self) -> Decimal {
@@ -300,9 +447,17 @@ impl Decimal {
         }
     }
 
+    pub fn is_negative(&self) -> bool {
+        self.value < 0
+    }
+
+    pub fn is_positive(&self) -> bool {
+        self.value > 0
+    }
+
     /// Creates a `Decimal` from a `f32` without taking care of precision
     #[inline]
-    pub fn from_f32(v: f32) -> Self {
+    pub(crate) fn from_f32(v: f32) -> Self {
         Self {
             value: (v * (DECIMAL_PART_POW as f32)) as i128,
         }
@@ -316,7 +471,7 @@ impl Decimal {
 
     /// Creates a `Decimal` from a `f64` without taking care of precision
     #[inline]
-    pub fn from_f64(v: f64) -> Self {
+    pub(crate) fn from_f64(v: f64) -> Self {
         Self {
             value: (v * (DECIMAL_PART_POW as f64)) as i128,
         }
@@ -327,31 +482,30 @@ impl Decimal {
     pub fn to_f64(&self) -> f64 {
         (self.value as f64) / (DECIMAL_PART_POW as f64)
     }
+
+    pub(super) fn as_i128(&self) -> i128 {
+        self.value / DECIMAL_PART_POW
+    }
 }
 
 impl TryFrom<Decimal> for i64 {
-    type Error = ();
+    type Error = DecimalOverflowError;
 
-    fn try_from(value: Decimal) -> Result<i64, ()> {
+    fn try_from(value: Decimal) -> Result<i64, DecimalOverflowError> {
         value
             .value
             .checked_div(DECIMAL_PART_POW)
-            .ok_or(())?
+            .ok_or(DecimalOverflowError)?
             .try_into()
-            .map_err(|_| ())
+            .map_err(|_| DecimalOverflowError)
     }
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::i128;
     use std::i64;
 
-    const MIN: Decimal = Decimal { value: i128::MIN };
-    const MAX: Decimal = Decimal { value: i128::MAX };
-    const STEP: Decimal = Decimal { value: 1 };
-
     #[test]
     fn from_str() {
         assert_eq!(Decimal::from_str("210").unwrap().to_string(), "210");
@@ -374,6 +528,16 @@ mod tests {
         );
     }
 
+    #[test]
+    fn format() {
+        assert_eq!(format!("{:02}", Decimal::from(0)), "00");
+        assert_eq!(format!("{:02}", Decimal::from(1)), "01");
+        assert_eq!(format!("{:02}", Decimal::from(10)), "10");
+        assert_eq!(format!("{:02}", Decimal::from(100)), "100");
+        assert_eq!(format!("{:02}", Decimal::from(-1)), "-1");
+        assert_eq!(format!("{:02}", Decimal::from(-10)), "-10");
+    }
+
     #[test]
     fn add() {
         assert!(MIN.checked_add(STEP).is_some());
diff --git a/lib/src/model/xsd/duration.rs b/lib/src/model/xsd/duration.rs
new file mode 100644
index 00000000..ec78f902
--- /dev/null
+++ b/lib/src/model/xsd/duration.rs
@@ -0,0 +1,382 @@
+use super::parser::duration_lexical_rep;
+use super::parser::parse_value;
+use super::*;
+use crate::model::xsd::decimal::DecimalOverflowError;
+use std::cmp::Ordering;
+use std::convert::TryFrom;
+use std::fmt;
+use std::i64;
+use std::ops::Neg;
+use std::str::FromStr;
+use std::time::Duration as StdDuration;
+
+/// [XML Schema `duration` datatype](https://www.w3.org/TR/xmlschema11-2/#duration) implementation.
+///
+/// It stores the duration using the two components model suggested by the specification:
+/// - a number of months encoded using a `i64`
+/// - a number of seconds encoded using a `Decimal`
+#[derive(Eq, PartialEq, Debug, Clone, Copy, Hash, Default)]
+pub struct Duration {
+    months: i64,
+    seconds: Decimal,
+}
+
+impl Duration {
+    pub fn new(months: impl Into<i64>, seconds: impl Into<Decimal>) -> Self {
+        Self {
+            months: months.into(),
+            seconds: seconds.into(),
+        }
+    }
+
+    pub fn from_le_bytes(bytes: [u8; 24]) -> Self {
+        let mut months = [0; 8];
+        months.copy_from_slice(&bytes[0..8]);
+        let mut seconds = [8; 16];
+        seconds.copy_from_slice(&bytes[8..24]);
+        Self {
+            months: i64::from_le_bytes(months),
+            seconds: Decimal::from_le_bytes(seconds),
+        }
+    }
+}
+
+impl TryFrom<StdDuration> for Duration {
+    type Error = DecimalOverflowError;
+
+    fn try_from(value: StdDuration) -> Result<Self, DecimalOverflowError> {
+        Ok(Self {
+            months: 0,
+            seconds: Decimal::new(
+                i128::try_from(value.as_nanos()).map_err(|_| DecimalOverflowError)?,
+                9,
+            )?,
+        })
+    }
+}
+
+impl FromStr for Duration {
+    type Err = XsdParseError;
+
+    fn from_str(input: &str) -> Result<Self, XsdParseError> {
+        parse_value(duration_lexical_rep, input)
+    }
+}
+
+impl fmt::Display for Duration {
+    #[allow(clippy::many_single_char_names)]
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut ym = self.months;
+        let mut ss = self.seconds;
+
+        if ym < 0 || ss < 0.into() {
+            write!(f, "-")?;
+            ym = -ym;
+            ss = -ss;
+        }
+        write!(f, "P")?;
+
+        if ym == 0 && ss == 0.into() {
+            return write!(f, "T0S");
+        }
+
+        {
+            let y = ym / 12;
+            let m = ym % 12;
+
+            if y != 0 {
+                if m != 0 {
+                    write!(f, "{}Y{}M", y, m)?;
+                } else {
+                    write!(f, "{}Y", y)?;
+                }
+            } else if m != 0 || ss == 0.into() {
+                write!(f, "{}M", m)?;
+            }
+        }
+
+        {
+            let s_int = ss.as_i128();
+            let d = s_int / 86400;
+            let h = (s_int % 86400) / 3600;
+            let m = (s_int % 3600) / 60;
+            let s = ss
+                .checked_sub(Decimal::try_from(d * 86400 + h * 3600 + m * 60).unwrap())
+                .unwrap(); //could not fail
+
+            if d != 0 {
+                write!(f, "{}D", d)?;
+            }
+
+            if h != 0 || m != 0 || s != 0.into() {
+                write!(f, "T")?;
+                if h != 0 {
+                    write!(f, "{}H", h)?;
+                }
+                if m != 0 {
+                    write!(f, "{}M", m)?;
+                }
+                if s != 0.into() {
+                    write!(f, "{}S", s)?;
+                }
+            }
+        }
+        Ok(())
+    }
+}
+
+impl PartialOrd for Duration {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        let first = DateTime::new(1969, 9, 1, 0, 0, 0.into(), None).ok()?;
+        let first_result = first
+            .checked_add_duration(*self)?
+            .partial_cmp(&first.checked_add_duration(*other)?);
+        let second = DateTime::new(1697, 2, 1, 0, 0, 0.into(), None).ok()?;
+        let second_result = second
+            .checked_add_duration(*self)?
+            .partial_cmp(&second.checked_add_duration(*other)?);
+        let third = DateTime::new(1903, 3, 1, 0, 0, 0.into(), None).ok()?;
+        let third_result = third
+            .checked_add_duration(*self)?
+            .partial_cmp(&third.checked_add_duration(*other)?);
+        let fourth = DateTime::new(1903, 7, 1, 0, 0, 0.into(), None).ok()?;
+        let fourth_result = fourth
+            .checked_add_duration(*self)?
+            .partial_cmp(&fourth.checked_add_duration(*other)?);
+        if first_result == second_result
+            && second_result == third_result
+            && third_result == fourth_result
+        {
+            first_result
+        } else {
+            None
+        }
+    }
+}
+
+impl Duration {
+    /// [fn:years-from-duration](https://www.w3.org/TR/xpath-functions/#func-years-from-duration)
+    pub fn years(&self) -> i64 {
+        self.months / 12
+    }
+
+    /// [fn:months-from-duration](https://www.w3.org/TR/xpath-functions/#func-months-from-duration)
+    pub fn months(&self) -> i64 {
+        self.months % 12
+    }
+
+    /// [fn:days-from-duration](https://www.w3.org/TR/xpath-functions/#func-days-from-duration)
+    pub fn days(&self) -> i64 {
+        (self.seconds.as_i128() / 86400) as i64
+    }
+
+    /// [fn:hours-from-duration](https://www.w3.org/TR/xpath-functions/#func-hours-from-duration)
+    pub fn hours(&self) -> i64 {
+        ((self.seconds.as_i128() % 86400) / 3600) as i64
+    }
+
+    /// [fn:minutes-from-duration](https://www.w3.org/TR/xpath-functions/#func-minutes-from-duration)
+    pub fn minutes(&self) -> i64 {
+        ((self.seconds.as_i128() % 3600) / 60) as i64
+    }
+
+    /// [fn:seconds-from-duration](https://www.w3.org/TR/xpath-functions/#func-seconds-from-duration)
+    pub fn seconds(&self) -> Decimal {
+        self.seconds.checked_rem(60).unwrap()
+    }
+
+    pub(super) fn all_months(&self) -> i64 {
+        self.months
+    }
+
+    pub(super) fn all_seconds(&self) -> Decimal {
+        self.seconds
+    }
+
+    pub fn to_le_bytes(&self) -> [u8; 24] {
+        let mut bytes = [0; 24];
+        bytes[0..8].copy_from_slice(&self.months.to_le_bytes());
+        bytes[8..24].copy_from_slice(&self.seconds.to_le_bytes());
+        bytes
+    }
+
+    /// [op:add-yearMonthDurations](https://www.w3.org/TR/xpath-functions/#func-add-yearMonthDurations) and [op:add-dayTimeDurations](https://www.w3.org/TR/xpath-functions/#func-add-dayTimeDurations)
+    pub fn checked_add(&self, rhs: impl Into<Self>) -> Option<Self> {
+        let rhs = rhs.into();
+        Some(Self {
+            months: self.months.checked_add(rhs.months)?,
+            seconds: self.seconds.checked_add(rhs.seconds)?,
+        })
+    }
+
+    /// [op:subtract-yearMonthDurations](https://www.w3.org/TR/xpath-functions/#func-subtract-yearMonthDurations) and [op:subtract-dayTimeDurations](https://www.w3.org/TR/xpath-functions/#func-subtract-dayTimeDurations)
+    pub fn checked_sub(&self, rhs: impl Into<Self>) -> Option<Self> {
+        let rhs = rhs.into();
+        Some(Self {
+            months: self.months.checked_sub(rhs.months)?,
+            seconds: self.seconds.checked_sub(rhs.seconds)?,
+        })
+    }
+}
+
+impl Neg for Duration {
+    type Output = Self;
+
+    fn neg(self) -> Self {
+        Self {
+            months: self.months.neg(),
+            seconds: self.seconds.neg(),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn from_str() {
+        let min = Duration::new(
+            i64::MIN + 1,
+            decimal::MIN.checked_add(decimal::STEP).unwrap(),
+        );
+        let max = Duration::new(i64::MAX, decimal::MAX);
+
+        assert_eq!(Duration::from_str("P1Y").unwrap().to_string(), "P1Y");
+        assert_eq!(Duration::from_str("P1M").unwrap().to_string(), "P1M");
+        assert_eq!(Duration::from_str("P1D").unwrap().to_string(), "P1D");
+        assert_eq!(Duration::from_str("PT1H").unwrap().to_string(), "PT1H");
+        assert_eq!(Duration::from_str("PT1M").unwrap().to_string(), "PT1M");
+        assert_eq!(Duration::from_str("PT1.1S").unwrap().to_string(), "PT1.1S");
+        assert_eq!(Duration::from_str("-P1Y").unwrap().to_string(), "-P1Y");
+        assert_eq!(Duration::from_str("-P1M").unwrap().to_string(), "-P1M");
+        assert_eq!(Duration::from_str("-P1D").unwrap().to_string(), "-P1D");
+        assert_eq!(Duration::from_str("-PT1H").unwrap().to_string(), "-PT1H");
+        assert_eq!(Duration::from_str("-PT1M").unwrap().to_string(), "-PT1M");
+        assert_eq!(
+            Duration::from_str("-PT1.1S").unwrap().to_string(),
+            "-PT1.1S"
+        );
+        assert_eq!(Duration::from_str(&max.to_string()).unwrap(), max);
+        assert_eq!(Duration::from_str(&min.to_string()).unwrap(), min);
+    }
+
+    #[test]
+    fn equals() {
+        assert_eq!(
+            Duration::from_str("P1Y").unwrap(),
+            Duration::from_str("P12M").unwrap()
+        );
+        assert_eq!(
+            Duration::from_str("PT24H").unwrap(),
+            Duration::from_str("P1D").unwrap()
+        );
+        assert_ne!(
+            Duration::from_str("P1Y").unwrap(),
+            Duration::from_str("P365D").unwrap()
+        );
+        assert_eq!(
+            Duration::from_str("P0Y").unwrap(),
+            Duration::from_str("P0D").unwrap()
+        );
+        assert_ne!(
+            Duration::from_str("P1Y").unwrap(),
+            Duration::from_str("P365D").unwrap()
+        );
+        assert_eq!(
+            Duration::from_str("P2Y").unwrap(),
+            Duration::from_str("P24M").unwrap()
+        );
+        assert_eq!(
+            Duration::from_str("P10D").unwrap(),
+            Duration::from_str("PT240H").unwrap()
+        );
+        assert_eq!(
+            Duration::from_str("P2Y0M0DT0H0M0S").unwrap(),
+            Duration::from_str("P24M").unwrap()
+        );
+        assert_eq!(
+            Duration::from_str("P0Y0M10D").unwrap(),
+            Duration::from_str("PT240H").unwrap()
+        );
+    }
+
+    #[test]
+    fn years() {
+        assert_eq!(Duration::from_str("P20Y15M").unwrap().years(), 21);
+        assert_eq!(Duration::from_str("-P15M").unwrap().years(), -1);
+        assert_eq!(Duration::from_str("-P2DT15H").unwrap().years(), 0);
+    }
+
+    #[test]
+    fn months() {
+        assert_eq!(Duration::from_str("P20Y15M").unwrap().months(), 3);
+        assert_eq!(Duration::from_str("-P20Y18M").unwrap().months(), -6);
+        assert_eq!(Duration::from_str("-P2DT15H0M0S").unwrap().months(), 0);
+    }
+
+    #[test]
+    fn days() {
+        assert_eq!(Duration::from_str("P3DT10H").unwrap().days(), 3);
+        assert_eq!(Duration::from_str("P3DT55H").unwrap().days(), 5);
+        assert_eq!(Duration::from_str("P3Y5M").unwrap().days(), 0);
+    }
+
+    #[test]
+    fn hours() {
+        assert_eq!(Duration::from_str("P3DT10H").unwrap().hours(), 10);
+        assert_eq!(Duration::from_str("P3DT12H32M12S").unwrap().hours(), 12);
+        assert_eq!(Duration::from_str("PT123H").unwrap().hours(), 3);
+        assert_eq!(Duration::from_str("-P3DT10H").unwrap().hours(), -10);
+    }
+
+    #[test]
+    fn minutes() {
+        assert_eq!(Duration::from_str("P3DT10H").unwrap().minutes(), 0);
+        assert_eq!(Duration::from_str("-P5DT12H30M").unwrap().minutes(), -30);
+    }
+
+    #[test]
+    fn seconds() {
+        assert_eq!(
+            Duration::from_str("P3DT10H12.5S").unwrap().seconds(),
+            Decimal::from_str("12.5").unwrap()
+        );
+        assert_eq!(
+            Duration::from_str("-PT256S").unwrap().seconds(),
+            Decimal::from_str("-16.0").unwrap()
+        );
+    }
+
+    #[test]
+    fn add() {
+        assert_eq!(
+            Duration::from_str("P2Y11M")
+                .unwrap()
+                .checked_add(Duration::from_str("P3Y3M").unwrap()),
+            Some(Duration::from_str("P6Y2M").unwrap())
+        );
+        assert_eq!(
+            Duration::from_str("P2DT12H5M")
+                .unwrap()
+                .checked_add(Duration::from_str("P5DT12H").unwrap()),
+            Some(Duration::from_str("P8DT5M").unwrap())
+        );
+    }
+
+    #[test]
+    fn sub() {
+        assert_eq!(
+            Duration::from_str("P2Y11M")
+                .unwrap()
+                .checked_sub(Duration::from_str("P3Y3M").unwrap()),
+            Some(Duration::from_str("-P4M").unwrap())
+        );
+        assert_eq!(
+            Duration::from_str("P2DT12H")
+                .unwrap()
+                .checked_sub(Duration::from_str("P1DT10H30M").unwrap()),
+            Some(Duration::from_str("P1DT1H30M").unwrap())
+        );
+    }
+}
diff --git a/lib/src/model/xsd/mod.rs b/lib/src/model/xsd/mod.rs
index d932b8cc..c42fabe9 100644
--- a/lib/src/model/xsd/mod.rs
+++ b/lib/src/model/xsd/mod.rs
@@ -1,3 +1,9 @@
-mod decimal;
+pub mod date_time;
+pub mod decimal;
+mod duration;
+mod parser;
 
+pub use self::date_time::{Date, DateTime, Time};
 pub use self::decimal::Decimal;
+pub use self::duration::Duration;
+pub use self::parser::XsdParseError;
diff --git a/lib/src/model/xsd/parser.rs b/lib/src/model/xsd/parser.rs
new file mode 100644
index 00000000..e583f495
--- /dev/null
+++ b/lib/src/model/xsd/parser.rs
@@ -0,0 +1,462 @@
+use super::*;
+use nom::branch::alt;
+use nom::bytes::complete::{tag, take_while};
+use nom::character::complete::{char, digit0, digit1};
+use nom::combinator::{map, opt, recognize};
+use nom::error::{ErrorKind, ParseError};
+use nom::multi::many1;
+use nom::sequence::{preceded, terminated, tuple};
+use nom::Err;
+use nom::{IResult, Needed};
+use std::str::FromStr;
+
+use super::date_time::DateTimeError;
+use super::decimal::ParseDecimalError;
+use crate::model::xsd::date_time::TimezoneOffset;
+use nom::bytes::streaming::take_while_m_n;
+use rand::distributions::weighted::alias_method::Weight;
+use std::error::Error;
+use std::fmt;
+use std::num::ParseIntError;
+
+#[derive(Debug, Clone)]
+pub struct XsdParseError {
+    kind: XsdParseErrorKind,
+}
+
+#[derive(Debug, Clone)]
+enum XsdParseErrorKind {
+    NomKind(ErrorKind),
+    NomChar(char),
+    MissingData(Needed),
+    TooMuchData { count: usize },
+    Overflow,
+    ParseInt(ParseIntError),
+    ParseDecimal(ParseDecimalError),
+    OutOfIntegerRange { value: u8, min: u8, max: u8 },
+    DateTime(DateTimeError),
+}
+
+impl fmt::Display for XsdParseError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match &self.kind {
+            XsdParseErrorKind::NomKind(kind) => {
+                write!(f, "Invalid XML Schema value: {}", kind.description())
+            }
+            XsdParseErrorKind::NomChar(c) => {
+                write!(f, "Unexpected character in XML Schema value: '{}'", c)
+            }
+            XsdParseErrorKind::MissingData(Needed::Unknown) => {
+                write!(f, "Too small XML Schema value")
+            }
+            XsdParseErrorKind::MissingData(Needed::Size(size)) => {
+                write!(f, "Too small XML Schema value: missing {} chars", size)
+            }
+            XsdParseErrorKind::TooMuchData { count } => {
+                write!(f, "Too long XML Schema value: {} extra chars", count)
+            }
+            XsdParseErrorKind::Overflow => write!(f, "Computation overflow or undeflow"),
+            XsdParseErrorKind::ParseInt(error) => {
+                write!(f, "Error while parsing integer: {}", error)
+            }
+            XsdParseErrorKind::ParseDecimal(error) => {
+                write!(f, "Error while parsing decimal: {}", error)
+            }
+            XsdParseErrorKind::OutOfIntegerRange { value, min, max } => write!(
+                f,
+                "The integer {} is not between {} and {}",
+                value, min, max
+            ),
+            XsdParseErrorKind::DateTime(error) => error.fmt(f),
+        }
+    }
+}
+
+impl Error for XsdParseError {
+    fn source(&self) -> Option<&(dyn Error + 'static)> {
+        match &self.kind {
+            XsdParseErrorKind::ParseInt(error) => Some(error),
+            XsdParseErrorKind::ParseDecimal(error) => Some(error),
+            XsdParseErrorKind::DateTime(error) => Some(error),
+            _ => None,
+        }
+    }
+}
+
+impl ParseError<&str> for XsdParseError {
+    fn from_error_kind(_input: &str, kind: ErrorKind) -> Self {
+        Self {
+            kind: XsdParseErrorKind::NomKind(kind),
+        }
+    }
+
+    fn append(_input: &str, _kind: ErrorKind, other: Self) -> Self {
+        other
+    }
+
+    fn from_char(_input: &str, c: char) -> Self {
+        Self {
+            kind: XsdParseErrorKind::NomChar(c),
+        }
+    }
+
+    fn or(self, other: Self) -> Self {
+        other
+    }
+
+    fn add_context(_input: &str, _ctx: &'static str, other: Self) -> Self {
+        other
+    }
+}
+
+impl From<ParseIntError> for XsdParseError {
+    fn from(error: ParseIntError) -> Self {
+        XsdParseError {
+            kind: XsdParseErrorKind::ParseInt(error),
+        }
+    }
+}
+
+impl From<ParseDecimalError> for XsdParseError {
+    fn from(error: ParseDecimalError) -> Self {
+        XsdParseError {
+            kind: XsdParseErrorKind::ParseDecimal(error),
+        }
+    }
+}
+
+impl From<DateTimeError> for XsdParseError {
+    fn from(error: DateTimeError) -> Self {
+        XsdParseError {
+            kind: XsdParseErrorKind::DateTime(error),
+        }
+    }
+}
+
+impl From<Err<XsdParseError>> for XsdParseError {
+    fn from(err: Err<XsdParseError>) -> Self {
+        match err {
+            Err::Incomplete(needed) => XsdParseError {
+                kind: XsdParseErrorKind::MissingData(needed),
+            },
+            Err::Error(e) | Err::Failure(e) => e,
+        }
+    }
+}
+
+type XsdResult<'a, T> = IResult<&'a str, T, XsdParseError>;
+
+const OVERFLOW_ERROR: XsdParseError = XsdParseError {
+    kind: XsdParseErrorKind::Overflow,
+};
+
+pub fn parse_value<'a, T>(
+    f: impl Fn(&'a str) -> XsdResult<'a, T>,
+    input: &'a str,
+) -> Result<T, XsdParseError> {
+    let (left, result) = f(input)?;
+    if left.is_empty() {
+        Ok(result)
+    } else {
+        Err(XsdParseError {
+            kind: XsdParseErrorKind::TooMuchData { count: left.len() },
+        })
+    }
+}
+
+//TODO: check every computation
+
+// [6]   duYearFrag ::= unsignedNoDecimalPtNumeral 'Y'
+fn du_year_frag(input: &str) -> XsdResult<i64> {
+    terminated(unsigned_no_decimal_pt_numeral, char('Y'))(input)
+}
+
+// [7]   duMonthFrag ::= unsignedNoDecimalPtNumeral 'M'
+fn du_month_frag(input: &str) -> XsdResult<i64> {
+    terminated(unsigned_no_decimal_pt_numeral, char('M'))(input)
+}
+
+//  [8]   duDayFrag ::= unsignedNoDecimalPtNumeral 'D'
+fn du_day_frag(input: &str) -> XsdResult<i64> {
+    terminated(unsigned_no_decimal_pt_numeral, char('D'))(input)
+}
+
+// [9]   duHourFrag ::= unsignedNoDecimalPtNumeral 'H'
+fn du_hour_frag(input: &str) -> XsdResult<i64> {
+    terminated(unsigned_no_decimal_pt_numeral, char('H'))(input)
+}
+
+// [10]   duMinuteFrag ::= unsignedNoDecimalPtNumeral 'M'
+fn du_minute_frag(input: &str) -> XsdResult<i64> {
+    terminated(unsigned_no_decimal_pt_numeral, char('M'))(input)
+}
+
+// [11]   duSecondFrag ::= (unsignedNoDecimalPtNumeral | unsignedDecimalPtNumeral) 'S'
+fn du_second_frag(input: &str) -> XsdResult<Decimal> {
+    terminated(
+        map_res(
+            recognize(tuple((digit0, opt(preceded(char('.'), digit0))))),
+            Decimal::from_str,
+        ),
+        char('S'),
+    )(input)
+}
+
+// [12]   duYearMonthFrag ::= (duYearFrag duMonthFrag?) | duMonthFrag
+fn du_year_month_frag(input: &str) -> XsdResult<i64> {
+    alt((
+        map(tuple((du_year_frag, opt(du_month_frag))), |(y, m)| {
+            12 * y + m.unwrap_or(0)
+        }),
+        du_month_frag,
+    ))(input)
+}
+
+// [13]   duTimeFrag ::= 'T' ((duHourFrag duMinuteFrag? duSecondFrag?) | (duMinuteFrag duSecondFrag?) | duSecondFrag)
+fn du_time_frag(input: &str) -> XsdResult<Decimal> {
+    preceded(
+        char('T'),
+        alt((
+            map_res(
+                tuple((du_hour_frag, opt(du_minute_frag), opt(du_second_frag))),
+                |(h, m, s)| {
+                    Decimal::from(3600 * h + 60 * m.unwrap_or(0))
+                        .checked_add(s.unwrap_or_else(Decimal::default))
+                        .ok_or(OVERFLOW_ERROR)
+                },
+            ),
+            map_res(tuple((du_minute_frag, opt(du_second_frag))), |(m, s)| {
+                Decimal::from(m * 60)
+                    .checked_add(s.unwrap_or_else(Decimal::default))
+                    .ok_or(OVERFLOW_ERROR)
+            }),
+            du_second_frag,
+        )),
+    )(input)
+}
+
+// [14]   duDayTimeFrag ::= (duDayFrag duTimeFrag?) | duTimeFrag
+fn du_day_time_frag(input: &str) -> XsdResult<Decimal> {
+    alt((
+        map_res(tuple((du_day_frag, opt(du_time_frag))), |(d, t)| {
+            Decimal::from(d)
+                .checked_mul(Decimal::from(86400))
+                .ok_or(OVERFLOW_ERROR)?
+                .checked_add(t.unwrap_or_else(Decimal::default))
+                .ok_or(OVERFLOW_ERROR)
+        }),
+        du_time_frag,
+    ))(input)
+}
+
+// [15]   durationLexicalRep ::= '-'? 'P' ((duYearMonthFrag duDayTimeFrag?) | duDayTimeFrag)
+pub fn duration_lexical_rep(input: &str) -> XsdResult<Duration> {
+    map(
+        tuple((
+            opt(char('-')),
+            preceded(
+                char('P'),
+                alt((
+                    map(
+                        tuple((du_year_month_frag, opt(du_day_time_frag))),
+                        |(y, d)| Duration::new(y, d.unwrap_or_else(Decimal::default)),
+                    ),
+                    map(du_day_time_frag, |d| Duration::new(0, d)),
+                )),
+            ),
+        )),
+        |(sign, duration)| {
+            if sign == Some('-') {
+                -duration
+            } else {
+                duration
+            }
+        },
+    )(input)
+}
+
+// [16]   dateTimeLexicalRep ::= yearFrag '-' monthFrag '-' dayFrag 'T' ((hourFrag ':' minuteFrag ':' secondFrag) | endOfDayFrag) timezoneFrag?
+pub fn date_time_lexical_rep(input: &str) -> XsdResult<DateTime> {
+    map_res(
+        tuple((
+            year_frag,
+            char('-'),
+            month_frag,
+            char('-'),
+            day_frag,
+            char('T'),
+            alt((
+                map(
+                    tuple((hour_frag, char(':'), minute_frag, char(':'), second_frag)),
+                    |(h, _, m, _, s)| (h, m, s),
+                ),
+                end_of_day_frag,
+            )),
+            opt(timezone_frag),
+        )),
+        |(year, _, month, _, day, _, (hours, minutes, seconds), timezone)| {
+            DateTime::new(year, month, day, hours, minutes, seconds, timezone)
+        },
+    )(input)
+}
+
+// [17]   timeLexicalRep ::= ((hourFrag ':' minuteFrag ':' secondFrag) | endOfDayFrag) timezoneFrag?
+pub fn time_lexical_rep(input: &str) -> XsdResult<Time> {
+    map_res(
+        tuple((
+            alt((
+                map(
+                    tuple((hour_frag, char(':'), minute_frag, char(':'), second_frag)),
+                    |(h, _, m, _, s)| (h, m, s),
+                ),
+                end_of_day_frag,
+            )),
+            opt(timezone_frag),
+        )),
+        |((hours, minutes, seconds), timezone)| Time::new(hours, minutes, seconds, timezone),
+    )(input)
+}
+
+// [18]   dateLexicalRep ::= yearFrag '-' monthFrag '-' dayFrag timezoneFrag?   Constraint:  Day-of-month Representations
+pub fn date_lexical_rep(input: &str) -> XsdResult<Date> {
+    map_res(
+        tuple((
+            year_frag,
+            char('-'),
+            month_frag,
+            char('-'),
+            day_frag,
+            opt(timezone_frag),
+        )),
+        |(year, _, month, _, day, timezone)| Date::new(year, month, day, timezone),
+    )(input)
+}
+
+//  [46]   unsignedNoDecimalPtNumeral ::= digit+
+fn unsigned_no_decimal_pt_numeral(input: &str) -> XsdResult<i64> {
+    map_res(digit1, |i| i64::from_str(i))(input)
+}
+
+// [56]   yearFrag ::= '-'? (([1-9] digit digit digit+)) | ('0' digit digit digit))
+fn year_frag(input: &str) -> XsdResult<i64> {
+    map_res(
+        recognize(tuple((
+            opt(char('-')),
+            take_while_m_n(4, usize::MAX, |c: char| c.is_ascii_digit()),
+        ))),
+        i64::from_str,
+    )(input)
+}
+
+// [57]   monthFrag ::= ('0' [1-9]) | ('1' [0-2])
+fn month_frag(input: &str) -> XsdResult<u8> {
+    map_res(take_while_m_n(2, 2, |c: char| c.is_ascii_digit()), |v| {
+        parsed_u8_range(v, 1, 12)
+    })(input)
+}
+
+// [58]   dayFrag ::= ('0' [1-9]) | ([12] digit) | ('3' [01])
+fn day_frag(input: &str) -> XsdResult<u8> {
+    map_res(take_while_m_n(2, 2, |c: char| c.is_ascii_digit()), |v| {
+        parsed_u8_range(v, 1, 31)
+    })(input)
+}
+
+// [59]   hourFrag ::= ([01] digit) | ('2' [0-3])
+fn hour_frag(input: &str) -> XsdResult<u8> {
+    map_res(take_while_m_n(2, 2, |c: char| c.is_ascii_digit()), |v| {
+        parsed_u8_range(v, 0, 23)
+    })(input)
+}
+
+// [60]   minuteFrag ::= [0-5] digit
+fn minute_frag(input: &str) -> XsdResult<u8> {
+    map_res(take_while_m_n(2, 2, |c: char| c.is_ascii_digit()), |v| {
+        parsed_u8_range(v, 0, 59)
+    })(input)
+}
+
+// [61]   secondFrag ::= ([0-5] digit) ('.' digit+)?
+fn second_frag(input: &str) -> XsdResult<Decimal> {
+    map_res(
+        recognize(tuple((
+            take_while_m_n(2, 2, |c: char| c.is_ascii_digit()),
+            opt(preceded(
+                char('.'),
+                take_while(|c: char| c.is_ascii_digit()),
+            )),
+        ))),
+        |v| {
+            let value = Decimal::from_str(v)?;
+            if Decimal::from(0) <= value && value < Decimal::from(60) {
+                Ok(value)
+            } else {
+                Err(XsdParseError {
+                    kind: XsdParseErrorKind::OutOfIntegerRange {
+                        value: value.as_i128() as u8,
+                        min: 0,
+                        max: 60,
+                    },
+                })
+            }
+        },
+    )(input)
+}
+
+// [62]   endOfDayFrag ::= '24:00:00' ('.' '0'+)?
+fn end_of_day_frag(input: &str) -> XsdResult<(u8, u8, Decimal)> {
+    map(
+        recognize(tuple((
+            tag("24:00:00"),
+            opt(preceded(char('.'), many1(char('0')))),
+        ))),
+        |_| (24, 0, 0.into()),
+    )(input)
+}
+
+// [63]   timezoneFrag ::= 'Z' | ('+' | '-') (('0' digit | '1' [0-3]) ':' minuteFrag | '14:00')
+fn timezone_frag(input: &str) -> XsdResult<TimezoneOffset> {
+    alt((
+        map(char('Z'), |_| TimezoneOffset::utc()),
+        map(
+            tuple((
+                alt((map(char('+'), |_| 1), map(char('-'), |_| -1))),
+                alt((
+                    map(
+                        tuple((
+                            map_res(take_while_m_n(2, 2, |c: char| c.is_ascii_digit()), |v| {
+                                parsed_u8_range(v, 0, 13)
+                            }),
+                            char(':'),
+                            minute_frag,
+                        )),
+                        |(hours, _, minutes)| i16::from(hours) * 60 + i16::from(minutes),
+                    ),
+                    map(tag("14:00"), |_| 14 * 60),
+                )),
+            )),
+            |(sign, value)| TimezoneOffset::new(sign * value),
+        ),
+    ))(input)
+}
+
+fn parsed_u8_range(input: &str, min: u8, max: u8) -> Result<u8, XsdParseError> {
+    let value = u8::from_str(input)?;
+    if min <= value && value <= max {
+        Ok(value)
+    } else {
+        Err(XsdParseError {
+            kind: XsdParseErrorKind::OutOfIntegerRange { value, min, max },
+        })
+    }
+}
+
+pub fn map_res<'a, O1, O2, E2: Into<XsdParseError>>(
+    first: impl Fn(&'a str) -> XsdResult<'a, O1>,
+    second: impl Fn(O1) -> Result<O2, E2>,
+) -> impl Fn(&'a str) -> XsdResult<'a, O2> {
+    move |input| {
+        let (input, o1) = first(input)?;
+        Ok((input, second(o1).map_err(|e| Err::Error(e.into()))?))
+    }
+}
diff --git a/lib/src/sparql/eval.rs b/lib/src/sparql/eval.rs
index c9ece985..64d238ed 100644
--- a/lib/src/sparql/eval.rs
+++ b/lib/src/sparql/eval.rs
@@ -1,4 +1,4 @@
-use crate::model::xsd::Decimal;
+use crate::model::xsd::*;
 use crate::model::BlankNode;
 use crate::model::Triple;
 use crate::sparql::algebra::GraphPattern;
@@ -8,7 +8,6 @@ use crate::sparql::ServiceHandler;
 use crate::store::numeric_encoder::*;
 use crate::store::StoreConnection;
 use crate::Result;
-use chrono::prelude::*;
 use digest::Digest;
 use failure::format_err;
 use md5::Md5;
@@ -22,7 +21,6 @@ use sha2::{Sha256, Sha384, Sha512};
 use std::cmp::Ordering;
 use std::collections::{BTreeMap, HashMap, HashSet};
 use std::convert::{TryFrom, TryInto};
-use std::fmt::Write;
 use std::hash::Hash;
 use std::iter::Iterator;
 use std::iter::{empty, once};
@@ -37,7 +35,7 @@ pub struct SimpleEvaluator<S: StoreConnection> {
     dataset: DatasetView<S>,
     base_iri: Option<Iri<String>>,
     bnodes_map: Mutex<BTreeMap<u128, u128>>,
-    now: DateTime<FixedOffset>,
+    now: DateTime,
     service_handler: Box<dyn ServiceHandler>,
 }
 
@@ -51,7 +49,7 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
             dataset,
             bnodes_map: Mutex::new(BTreeMap::default()),
             base_iri,
-            now: Utc::now().with_timezone(&FixedOffset::east(0)),
+            now: DateTime::now().unwrap(),
             service_handler,
         }
     }
@@ -813,37 +811,60 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
                     Some(false.into())
                 }
             }
-            PlanExpression::Add(a, b) => Some(match self.parse_numeric_operands(a, b, tuple)? {
-                NumericBinaryOperands::Float(v1, v2) => (v1 + v2).into(),
-                NumericBinaryOperands::Double(v1, v2) => (v1 + v2).into(),
-                NumericBinaryOperands::Integer(v1, v2) => v1.checked_add(v2)?.into(),
-                NumericBinaryOperands::Decimal(v1, v2) => v1.checked_add(v2)?.into(),
-            }),
+            PlanExpression::Add(a, b) => match self.parse_numeric_operands(a, b, tuple)? {
+                NumericBinaryOperands::Float(v1, v2) => Some((v1 + v2).into()),
+                NumericBinaryOperands::Double(v1, v2) => Some((v1 + v2).into()),
+                NumericBinaryOperands::Integer(v1, v2) => Some(v1.checked_add(v2)?.into()),
+                NumericBinaryOperands::Decimal(v1, v2) => Some(v1.checked_add(v2)?.into()),
+                NumericBinaryOperands::Duration(v1, v2) => Some(v1.checked_add(v2)?.into()),
+                NumericBinaryOperands::DateTimeDuration(v1, v2) => {
+                    Some(v1.checked_add_duration(v2)?.into())
+                }
+                NumericBinaryOperands::DateDuration(v1, v2) => {
+                    Some(v1.checked_add_duration(v2)?.into())
+                }
+                NumericBinaryOperands::TimeDuration(v1, v2) => {
+                    Some(v1.checked_add_duration(v2)?.into())
+                }
+                _ => None,
+            },
             PlanExpression::Sub(a, b) => Some(match self.parse_numeric_operands(a, b, tuple)? {
                 NumericBinaryOperands::Float(v1, v2) => (v1 - v2).into(),
                 NumericBinaryOperands::Double(v1, v2) => (v1 - v2).into(),
                 NumericBinaryOperands::Integer(v1, v2) => v1.checked_sub(v2)?.into(),
                 NumericBinaryOperands::Decimal(v1, v2) => v1.checked_sub(v2)?.into(),
+                NumericBinaryOperands::Duration(v1, v2) => v1.checked_sub(v2)?.into(),
+                NumericBinaryOperands::DateTime(v1, v2) => v1.checked_sub(v2)?.into(),
+                NumericBinaryOperands::Date(v1, v2) => v1.checked_sub(v2)?.into(),
+                NumericBinaryOperands::Time(v1, v2) => v1.checked_sub(v2)?.into(),
+                NumericBinaryOperands::DateTimeDuration(v1, v2) => {
+                    v1.checked_sub_duration(v2)?.into()
+                }
+                NumericBinaryOperands::DateDuration(v1, v2) => v1.checked_sub_duration(v2)?.into(),
+                NumericBinaryOperands::TimeDuration(v1, v2) => v1.checked_sub_duration(v2)?.into(),
             }),
-            PlanExpression::Mul(a, b) => Some(match self.parse_numeric_operands(a, b, tuple)? {
-                NumericBinaryOperands::Float(v1, v2) => (v1 * v2).into(),
-                NumericBinaryOperands::Double(v1, v2) => (v1 * v2).into(),
-                NumericBinaryOperands::Integer(v1, v2) => v1.checked_mul(v2)?.into(),
-                NumericBinaryOperands::Decimal(v1, v2) => v1.checked_mul(v2)?.into(),
-            }),
-            PlanExpression::Div(a, b) => Some(match self.parse_numeric_operands(a, b, tuple)? {
-                NumericBinaryOperands::Float(v1, v2) => (v1 / v2).into(),
-                NumericBinaryOperands::Double(v1, v2) => (v1 / v2).into(),
+            PlanExpression::Mul(a, b) => match self.parse_numeric_operands(a, b, tuple)? {
+                NumericBinaryOperands::Float(v1, v2) => Some((v1 * v2).into()),
+                NumericBinaryOperands::Double(v1, v2) => Some((v1 * v2).into()),
+                NumericBinaryOperands::Integer(v1, v2) => Some(v1.checked_mul(v2)?.into()),
+                NumericBinaryOperands::Decimal(v1, v2) => Some(v1.checked_mul(v2)?.into()),
+                _ => None,
+            },
+            PlanExpression::Div(a, b) => match self.parse_numeric_operands(a, b, tuple)? {
+                NumericBinaryOperands::Float(v1, v2) => Some((v1 / v2).into()),
+                NumericBinaryOperands::Double(v1, v2) => Some((v1 / v2).into()),
                 NumericBinaryOperands::Integer(v1, v2) => {
-                    Decimal::from(v1).checked_div(Decimal::from(v2))?.into()
+                    Some(Decimal::from(v1).checked_div(v2)?.into())
                 }
-                NumericBinaryOperands::Decimal(v1, v2) => v1.checked_div(v2)?.into(),
-            }),
+                NumericBinaryOperands::Decimal(v1, v2) => Some(v1.checked_div(v2)?.into()),
+                _ => None,
+            },
             PlanExpression::UnaryPlus(e) => match self.eval_expression(e, tuple)? {
                 EncodedTerm::FloatLiteral(value) => Some(value.into()),
                 EncodedTerm::DoubleLiteral(value) => Some(value.into()),
                 EncodedTerm::IntegerLiteral(value) => Some(value.into()),
                 EncodedTerm::DecimalLiteral(value) => Some(value.into()),
+                EncodedTerm::DurationLiteral(value) => Some(value.into()),
                 _ => None,
             },
             PlanExpression::UnaryMinus(e) => match self.eval_expression(e, tuple)? {
@@ -851,6 +872,7 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
                 EncodedTerm::DoubleLiteral(value) => Some((-value).into()),
                 EncodedTerm::IntegerLiteral(value) => Some((-value).into()),
                 EncodedTerm::DecimalLiteral(value) => Some((-value).into()),
+                EncodedTerm::DurationLiteral(value) => Some((-value).into()),
                 _ => None,
             },
             PlanExpression::UnaryNot(e) => self
@@ -1119,111 +1141,55 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
             }
             PlanExpression::Year(e) => match self.eval_expression(e, tuple)? {
                 EncodedTerm::DateLiteral(date) => Some(date.year().into()),
-                EncodedTerm::NaiveDateLiteral(date) => Some(date.year().into()),
                 EncodedTerm::DateTimeLiteral(date_time) => Some(date_time.year().into()),
-                EncodedTerm::NaiveDateTimeLiteral(date_time) => Some(date_time.year().into()),
                 _ => None,
             },
             PlanExpression::Month(e) => match self.eval_expression(e, tuple)? {
                 EncodedTerm::DateLiteral(date) => Some(date.year().into()),
-                EncodedTerm::NaiveDateLiteral(date) => Some(date.month().into()),
                 EncodedTerm::DateTimeLiteral(date_time) => Some(date_time.month().into()),
-                EncodedTerm::NaiveDateTimeLiteral(date_time) => Some(date_time.month().into()),
                 _ => None,
             },
             PlanExpression::Day(e) => match self.eval_expression(e, tuple)? {
                 EncodedTerm::DateLiteral(date) => Some(date.year().into()),
-                EncodedTerm::NaiveDateLiteral(date) => Some(date.day().into()),
                 EncodedTerm::DateTimeLiteral(date_time) => Some(date_time.day().into()),
-                EncodedTerm::NaiveDateTimeLiteral(date_time) => Some(date_time.day().into()),
                 _ => None,
             },
             PlanExpression::Hours(e) => match self.eval_expression(e, tuple)? {
-                EncodedTerm::NaiveTimeLiteral(time) => Some(time.hour().into()),
+                EncodedTerm::TimeLiteral(time) => Some(time.hour().into()),
                 EncodedTerm::DateTimeLiteral(date_time) => Some(date_time.hour().into()),
-                EncodedTerm::NaiveDateTimeLiteral(date_time) => Some(date_time.hour().into()),
                 _ => None,
             },
             PlanExpression::Minutes(e) => match self.eval_expression(e, tuple)? {
-                EncodedTerm::NaiveTimeLiteral(time) => Some(time.minute().into()),
+                EncodedTerm::TimeLiteral(time) => Some(time.minute().into()),
                 EncodedTerm::DateTimeLiteral(date_time) => Some(date_time.minute().into()),
-                EncodedTerm::NaiveDateTimeLiteral(date_time) => Some(date_time.minute().into()),
                 _ => None,
             },
             PlanExpression::Seconds(e) => match self.eval_expression(e, tuple)? {
-                EncodedTerm::NaiveTimeLiteral(time) => Some(
-                    Decimal::from(time.nanosecond())
-                        .checked_div(Decimal::from(1_000_000_000))?
-                        .checked_add(Decimal::from(time.second()))?
-                        .into(),
-                ),
-                EncodedTerm::DateTimeLiteral(date_time) => Some(
-                    Decimal::from(date_time.nanosecond())
-                        .checked_div(Decimal::from(1_000_000_000))?
-                        .checked_add(Decimal::from(date_time.second()))?
-                        .into(),
-                ),
-                EncodedTerm::NaiveDateTimeLiteral(date_time) => Some(
-                    Decimal::from(date_time.nanosecond())
-                        .checked_div(Decimal::from(1_000_000_000))?
-                        .checked_add(Decimal::from(date_time.second()))?
-                        .into(),
-                ),
+                EncodedTerm::TimeLiteral(time) => Some(time.second().into()),
+                EncodedTerm::DateTimeLiteral(date_time) => Some(date_time.second().into()),
                 _ => None,
             },
-            PlanExpression::Timezone(e) => {
-                let timezone = match self.eval_expression(e, tuple)? {
+            PlanExpression::Timezone(e) => Some(
+                match self.eval_expression(e, tuple)? {
                     EncodedTerm::DateLiteral(date) => date.timezone(),
+                    EncodedTerm::TimeLiteral(time) => time.timezone(),
                     EncodedTerm::DateTimeLiteral(date_time) => date_time.timezone(),
-                    _ => return None,
-                };
-                let mut result = String::with_capacity(9);
-                let mut shift = timezone.local_minus_utc();
-                if shift < 0 {
-                    write!(&mut result, "-").ok()?;
-                    shift = -shift
-                };
-                write!(&mut result, "PT").ok()?;
-
-                let hours = shift / 3600;
-                if hours > 0 {
-                    write!(&mut result, "{}H", hours).ok()?;
-                }
-
-                let minutes = (shift / 60) % 60;
-                if minutes > 0 {
-                    write!(&mut result, "{}M", minutes).ok()?;
-                }
-
-                let seconds = shift % 60;
-                if seconds > 0 || shift == 0 {
-                    write!(&mut result, "{}S", seconds).ok()?;
-                }
-                Some(EncodedTerm::TypedLiteral {
-                    value_id: self.build_string_id(&result)?,
-                    datatype_id: self
-                        .build_string_id("http://www.w3.org/2001/XMLSchema#dayTimeDuration")?,
-                })
-            }
+                    _ => None,
+                }?
+                .into(),
+            ),
             PlanExpression::Tz(e) => {
-                let timezone = match self.eval_expression(e, tuple)? {
-                    EncodedTerm::DateLiteral(date) => Some(date.timezone()),
-                    EncodedTerm::DateTimeLiteral(date_time) => Some(date_time.timezone()),
-                    EncodedTerm::NaiveDateLiteral(_)
-                    | EncodedTerm::NaiveTimeLiteral(_)
-                    | EncodedTerm::NaiveDateTimeLiteral(_) => None,
+                let timezone_offset = match self.eval_expression(e, tuple)? {
+                    EncodedTerm::DateLiteral(date) => date.timezone_offset(),
+                    EncodedTerm::TimeLiteral(time) => time.timezone_offset(),
+                    EncodedTerm::DateTimeLiteral(date_time) => date_time.timezone_offset(),
                     _ => return None,
                 };
-                Some(if let Some(timezone) = timezone {
-                    EncodedTerm::StringLiteral {
-                        value_id: if timezone.local_minus_utc() == 0 {
-                            self.build_string_id("Z")?
-                        } else {
-                            self.build_string_id(&timezone.to_string())?
-                        },
+                Some(match timezone_offset {
+                    Some(timezone_offset) => {
+                        self.build_string_literal(&timezone_offset.to_string())?
                     }
-                } else {
-                    ENCODED_EMPTY_STRING_LITERAL
+                    None => ENCODED_EMPTY_STRING_LITERAL,
                 })
             }
             PlanExpression::Now => Some(self.now.into()),
@@ -1376,18 +1342,15 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
             },
             PlanExpression::DateCast(e) => match self.eval_expression(e, tuple)? {
                 EncodedTerm::DateLiteral(value) => Some(value.into()),
-                EncodedTerm::NaiveDateLiteral(value) => Some(value.into()),
-                EncodedTerm::DateTimeLiteral(value) => Some(value.date().into()),
-                EncodedTerm::NaiveDateTimeLiteral(value) => Some(value.date().into()),
+                EncodedTerm::DateTimeLiteral(value) => Some(Date::from(value).into()),
                 EncodedTerm::StringLiteral { value_id } => {
                     parse_date_str(&*self.dataset.get_str(value_id).ok()??)
                 }
                 _ => None,
             },
             PlanExpression::TimeCast(e) => match self.eval_expression(e, tuple)? {
-                EncodedTerm::NaiveTimeLiteral(value) => Some(value.into()),
-                EncodedTerm::DateTimeLiteral(value) => Some(value.time().into()),
-                EncodedTerm::NaiveDateTimeLiteral(value) => Some(value.time().into()),
+                EncodedTerm::TimeLiteral(value) => Some(value.into()),
+                EncodedTerm::DateTimeLiteral(value) => Some(Time::from(value).into()),
                 EncodedTerm::StringLiteral { value_id } => {
                     parse_time_str(&*self.dataset.get_str(value_id).ok()??)
                 }
@@ -1395,12 +1358,19 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
             },
             PlanExpression::DateTimeCast(e) => match self.eval_expression(e, tuple)? {
                 EncodedTerm::DateTimeLiteral(value) => Some(value.into()),
-                EncodedTerm::NaiveDateTimeLiteral(value) => Some(value.into()),
+                EncodedTerm::DateLiteral(value) => Some(DateTime::from(value).into()),
                 EncodedTerm::StringLiteral { value_id } => {
                     parse_date_time_str(&*self.dataset.get_str(value_id).ok()??)
                 }
                 _ => None,
             },
+            PlanExpression::DurationCast(e) => match self.eval_expression(e, tuple)? {
+                EncodedTerm::DurationLiteral(value) => Some(value.into()),
+                EncodedTerm::StringLiteral { value_id } => {
+                    parse_duration_str(&*self.dataset.get_str(value_id).ok()??)
+                }
+                _ => None,
+            },
             PlanExpression::StringCast(e) => Some(EncodedTerm::StringLiteral {
                 value_id: self.to_string_id(self.eval_expression(e, tuple)?)?,
             }),
@@ -1414,7 +1384,7 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
             EncodedTerm::FloatLiteral(value) => Some(value != 0f32),
             EncodedTerm::DoubleLiteral(value) => Some(value != 0f64),
             EncodedTerm::IntegerLiteral(value) => Some(value != 0),
-            EncodedTerm::DecimalLiteral(value) => Some(value != Decimal::from(0)),
+            EncodedTerm::DecimalLiteral(value) => Some(value != Decimal::default()),
             _ => None,
         }
     }
@@ -1435,10 +1405,9 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
             EncodedTerm::IntegerLiteral(value) => self.build_string_id(&value.to_string()),
             EncodedTerm::DecimalLiteral(value) => self.build_string_id(&value.to_string()),
             EncodedTerm::DateLiteral(value) => self.build_string_id(&value.to_string()),
-            EncodedTerm::NaiveDateLiteral(value) => self.build_string_id(&value.to_string()),
-            EncodedTerm::NaiveTimeLiteral(value) => self.build_string_id(&value.to_string()),
+            EncodedTerm::TimeLiteral(value) => self.build_string_id(&value.to_string()),
             EncodedTerm::DateTimeLiteral(value) => self.build_string_id(&value.to_string()),
-            EncodedTerm::NaiveDateTimeLiteral(value) => self.build_string_id(&value.to_string()),
+            EncodedTerm::DurationLiteral(value) => self.build_string_id(&value.to_string()),
         }
     }
 
@@ -1690,54 +1659,21 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
             },
             EncodedTerm::DateLiteral(a) => match b {
                 EncodedTerm::DateLiteral(b) => Some(a == b),
-                EncodedTerm::NaiveDateLiteral(b) => {
-                    if a.naive_utc() == b {
-                        None
-                    } else {
-                        Some(false)
-                    }
-                }
                 EncodedTerm::TypedLiteral { .. } => None,
                 _ => Some(false),
             },
-            EncodedTerm::NaiveDateLiteral(a) => match b {
-                EncodedTerm::NaiveDateLiteral(b) => Some(a == b),
-                EncodedTerm::DateLiteral(b) => {
-                    if a == b.naive_utc() {
-                        None
-                    } else {
-                        Some(false)
-                    }
-                }
-                EncodedTerm::TypedLiteral { .. } => None,
-                _ => Some(false),
-            },
-            EncodedTerm::NaiveTimeLiteral(a) => match b {
-                EncodedTerm::NaiveTimeLiteral(b) => Some(a == b),
+            EncodedTerm::TimeLiteral(a) => match b {
+                EncodedTerm::TimeLiteral(b) => Some(a == b),
                 EncodedTerm::TypedLiteral { .. } => None,
                 _ => Some(false),
             },
             EncodedTerm::DateTimeLiteral(a) => match b {
                 EncodedTerm::DateTimeLiteral(b) => Some(a == b),
-                EncodedTerm::NaiveDateTimeLiteral(b) => {
-                    if a.naive_utc() == b {
-                        None
-                    } else {
-                        Some(false)
-                    }
-                }
                 EncodedTerm::TypedLiteral { .. } => None,
                 _ => Some(false),
             },
-            EncodedTerm::NaiveDateTimeLiteral(a) => match b {
-                EncodedTerm::NaiveDateTimeLiteral(b) => Some(a == b),
-                EncodedTerm::DateTimeLiteral(b) => {
-                    if a == b.naive_utc() {
-                        None
-                    } else {
-                        Some(false)
-                    }
-                }
+            EncodedTerm::DurationLiteral(a) => match b {
+                EncodedTerm::DurationLiteral(b) => Some(a == b),
                 EncodedTerm::TypedLiteral { .. } => None,
                 _ => Some(false),
             },
@@ -1796,60 +1732,61 @@ impl<'a, S: StoreConnection + 'a> SimpleEvaluator<S> {
                 }
             }
             EncodedTerm::FloatLiteral(a) => match b {
-                EncodedTerm::FloatLiteral(b) => a.partial_cmp(&b),
-                EncodedTerm::DoubleLiteral(b) => a.to_f64()?.partial_cmp(&b),
+                EncodedTerm::FloatLiteral(ref b) => a.partial_cmp(b),
+                EncodedTerm::DoubleLiteral(ref b) => a.to_f64()?.partial_cmp(b),
                 EncodedTerm::IntegerLiteral(b) => a.partial_cmp(&b.to_f32()?),
                 EncodedTerm::DecimalLiteral(b) => a.partial_cmp(&b.to_f32()),
                 _ => None,
             },
             EncodedTerm::DoubleLiteral(a) => match b {
                 EncodedTerm::FloatLiteral(b) => a.partial_cmp(&b.to_f64()?),
-                EncodedTerm::DoubleLiteral(b) => a.partial_cmp(&b),
+                EncodedTerm::DoubleLiteral(ref b) => a.partial_cmp(b),
                 EncodedTerm::IntegerLiteral(b) => a.partial_cmp(&b.to_f64()?),
                 EncodedTerm::DecimalLiteral(b) => a.partial_cmp(&b.to_f64()),
                 _ => None,
             },
             EncodedTerm::IntegerLiteral(a) => match b {
-                EncodedTerm::FloatLiteral(b) => a.to_f32()?.partial_cmp(&b),
-                EncodedTerm::DoubleLiteral(b) => a.to_f64()?.partial_cmp(&b),
-                EncodedTerm::IntegerLiteral(b) => a.partial_cmp(&b),
+                EncodedTerm::FloatLiteral(ref b) => a.to_f32()?.partial_cmp(b),
+                EncodedTerm::DoubleLiteral(ref b) => a.to_f64()?.partial_cmp(b),
+                EncodedTerm::IntegerLiteral(ref b) => a.partial_cmp(b),
                 EncodedTerm::DecimalLiteral(b) => Decimal::from(a).partial_cmp(&b),
                 _ => None,
             },
             EncodedTerm::DecimalLiteral(a) => match b {
-                EncodedTerm::FloatLiteral(b) => a.to_f32().partial_cmp(&b),
-                EncodedTerm::DoubleLiteral(b) => a.to_f64().partial_cmp(&b),
+                EncodedTerm::FloatLiteral(ref b) => a.to_f32().partial_cmp(b),
+                EncodedTerm::DoubleLiteral(ref b) => a.to_f64().partial_cmp(b),
                 EncodedTerm::IntegerLiteral(b) => a.partial_cmp(&Decimal::from(b)),
-                EncodedTerm::DecimalLiteral(b) => a.partial_cmp(&b),
-                _ => None,
-            },
-            EncodedTerm::DateLiteral(a) => match b {
-                EncodedTerm::DateLiteral(ref b) => a.partial_cmp(b),
-                EncodedTerm::NaiveDateLiteral(ref b) => a.naive_utc().partial_cmp(b), //TODO: check edges
+                EncodedTerm::DecimalLiteral(ref b) => a.partial_cmp(b),
                 _ => None,
             },
-            EncodedTerm::NaiveDateLiteral(a) => match b {
-                EncodedTerm::NaiveDateLiteral(ref b) => a.partial_cmp(b),
-                EncodedTerm::DateLiteral(ref b) => a.partial_cmp(&b.naive_utc()), //TODO: check edges
-                _ => None,
-            },
-            EncodedTerm::NaiveTimeLiteral(a) => {
-                if let EncodedTerm::NaiveTimeLiteral(ref b) = b {
+            EncodedTerm::DateLiteral(a) => {
+                if let EncodedTerm::DateLiteral(ref b) = b {
+                    a.partial_cmp(b)
+                } else {
+                    None
+                }
+            }
+            EncodedTerm::TimeLiteral(a) => {
+                if let EncodedTerm::TimeLiteral(ref b) = b {
+                    a.partial_cmp(b)
+                } else {
+                    None
+                }
+            }
+            EncodedTerm::DateTimeLiteral(a) => {
+                if let EncodedTerm::DateTimeLiteral(ref b) = b {
+                    a.partial_cmp(b)
+                } else {
+                    None
+                }
+            }
+            EncodedTerm::DurationLiteral(a) => {
+                if let EncodedTerm::DurationLiteral(ref b) = b {
                     a.partial_cmp(b)
                 } else {
                     None
                 }
             }
-            EncodedTerm::DateTimeLiteral(a) => match b {
-                EncodedTerm::DateTimeLiteral(ref b) => a.partial_cmp(b),
-                EncodedTerm::NaiveDateTimeLiteral(ref b) => a.naive_utc().partial_cmp(b), //TODO: check edges
-                _ => None,
-            },
-            EncodedTerm::NaiveDateTimeLiteral(a) => match b {
-                EncodedTerm::NaiveDateTimeLiteral(ref b) => a.partial_cmp(b),
-                EncodedTerm::DateTimeLiteral(ref b) => a.partial_cmp(&b.naive_utc()), //TODO: check edges
-                _ => None,
-            },
             _ => None,
         }
     }
@@ -1879,6 +1816,13 @@ enum NumericBinaryOperands {
     Double(f64, f64),
     Integer(i64, i64),
     Decimal(Decimal, Decimal),
+    Duration(Duration, Duration),
+    DateTime(DateTime, DateTime),
+    Time(Time, Time),
+    Date(Date, Date),
+    DateTimeDuration(DateTime, Duration),
+    TimeDuration(Time, Duration),
+    DateDuration(Date, Duration),
 }
 
 impl NumericBinaryOperands {
@@ -1932,6 +1876,27 @@ impl NumericBinaryOperands {
             (EncodedTerm::DecimalLiteral(v1), EncodedTerm::DecimalLiteral(v2)) => {
                 Some(NumericBinaryOperands::Decimal(v1, v2))
             }
+            (EncodedTerm::DurationLiteral(v1), EncodedTerm::DurationLiteral(v2)) => {
+                Some(NumericBinaryOperands::Duration(v1, v2))
+            }
+            (EncodedTerm::DateTimeLiteral(v1), EncodedTerm::DateTimeLiteral(v2)) => {
+                Some(NumericBinaryOperands::DateTime(v1, v2))
+            }
+            (EncodedTerm::DateLiteral(v1), EncodedTerm::DateLiteral(v2)) => {
+                Some(NumericBinaryOperands::Date(v1, v2))
+            }
+            (EncodedTerm::TimeLiteral(v1), EncodedTerm::TimeLiteral(v2)) => {
+                Some(NumericBinaryOperands::Time(v1, v2))
+            }
+            (EncodedTerm::DateTimeLiteral(v1), EncodedTerm::DurationLiteral(v2)) => {
+                Some(NumericBinaryOperands::DateTimeDuration(v1, v2))
+            }
+            (EncodedTerm::DateLiteral(v1), EncodedTerm::DurationLiteral(v2)) => {
+                Some(NumericBinaryOperands::DateDuration(v1, v2))
+            }
+            (EncodedTerm::TimeLiteral(v1), EncodedTerm::DurationLiteral(v2)) => {
+                Some(NumericBinaryOperands::TimeDuration(v1, v2))
+            }
             _ => None,
         }
     }
@@ -2452,6 +2417,8 @@ impl Accumulator for SumAccumulator {
                     NumericBinaryOperands::Double(v1, v2) => Some((v1 + v2).into()),
                     NumericBinaryOperands::Integer(v1, v2) => v1.checked_add(v2).map(|v| v.into()),
                     NumericBinaryOperands::Decimal(v1, v2) => v1.checked_add(v2).map(|v| v.into()),
+                    NumericBinaryOperands::Duration(v1, v2) => v1.checked_add(v2).map(|v| v.into()),
+                    _ => None,
                 };
             } else {
                 self.sum = None;
@@ -2483,13 +2450,15 @@ impl Accumulator for AvgAccumulator {
             Some(0.into())
         } else {
             //TODO: deduplicate?
+            //TODO: duration?
             match NumericBinaryOperands::new(sum, count)? {
                 NumericBinaryOperands::Float(v1, v2) => Some((v1 / v2).into()),
                 NumericBinaryOperands::Double(v1, v2) => Some((v1 / v2).into()),
-                NumericBinaryOperands::Integer(v1, v2) => Decimal::from(v1)
-                    .checked_div(Decimal::from(v2))
-                    .map(|v| v.into()),
+                NumericBinaryOperands::Integer(v1, v2) => {
+                    Decimal::from(v1).checked_div(v2).map(|v| v.into())
+                }
                 NumericBinaryOperands::Decimal(v1, v2) => v1.checked_div(v2).map(|v| v.into()),
+                _ => None,
             }
         }
     }
diff --git a/lib/src/sparql/plan.rs b/lib/src/sparql/plan.rs
index b07afbe3..207460df 100644
--- a/lib/src/sparql/plan.rs
+++ b/lib/src/sparql/plan.rs
@@ -303,6 +303,7 @@ pub enum PlanExpression {
     DateCast(Box<PlanExpression>),
     TimeCast(Box<PlanExpression>),
     DateTimeCast(Box<PlanExpression>),
+    DurationCast(Box<PlanExpression>),
     StringCast(Box<PlanExpression>),
 }
 
diff --git a/lib/src/sparql/plan_builder.rs b/lib/src/sparql/plan_builder.rs
index 5766dd11..09bd30d7 100644
--- a/lib/src/sparql/plan_builder.rs
+++ b/lib/src/sparql/plan_builder.rs
@@ -641,6 +641,14 @@ impl<E: Encoder> PlanBuilder<E> {
                             graph_name,
                             "dateTime",
                         )?
+                    } else if *name == *xsd::DURATION {
+                        self.build_cast(
+                            parameters,
+                            PlanExpression::DurationCast,
+                            variables,
+                            graph_name,
+                            "duration",
+                        )?
                     } else if *name == *xsd::STRING {
                         self.build_cast(
                             parameters,
diff --git a/lib/src/store/mod.rs b/lib/src/store/mod.rs
index c5235696..0e4475ed 100644
--- a/lib/src/store/mod.rs
+++ b/lib/src/store/mod.rs
@@ -121,7 +121,6 @@ impl<S: StoreConnection> RepositoryConnection for StoreRepositoryConnection<S> {
         self.inner.contains(&quad.into())
     }
 
-    #[must_use]
     fn transaction(&self, f: impl FnOnce(&mut Self::Transaction) -> Result<()>) -> Result<()> {
         let mut transaction = StoreRepositoryTransaction {
             inner: self.inner.transaction(),
diff --git a/lib/src/store/numeric_encoder.rs b/lib/src/store/numeric_encoder.rs
index fa6eb002..abf159a7 100644
--- a/lib/src/store/numeric_encoder.rs
+++ b/lib/src/store/numeric_encoder.rs
@@ -1,11 +1,9 @@
 use crate::model::vocab::rdf;
 use crate::model::vocab::xsd;
-use crate::model::xsd::Decimal;
+use crate::model::xsd::*;
 use crate::model::*;
 use crate::Result;
 use byteorder::{LittleEndian, ReadBytesExt};
-use chrono::format::{parse, Parsed, StrftimeItems};
-use chrono::prelude::*;
 use failure::format_err;
 use md5::digest::Digest;
 use md5::Md5;
@@ -30,6 +28,7 @@ const XSD_DECIMAL_ID: u128 = 0x3ca7_b56d_a746_719a_6800_081f_bb59_ea33;
 const XSD_DATE_TIME_ID: u128 = 0xc206_6749_e0e5_015e_f7ee_33b7_b28c_c010;
 const XSD_DATE_ID: u128 = 0xcaae_3cc4_f23f_4c5a_7717_dd19_e30a_84b8;
 const XSD_TIME_ID: u128 = 0x7af4_6a16_1b02_35d7_9a79_07ba_3da9_48bb;
+const XSD_DURATION_ID: u128 = 0x78ab_8431_984b_6b06_c42d_6271_b82e_487d;
 
 pub fn get_str_id(value: &str) -> u128 {
     let mut id = [0 as u8; 16];
@@ -50,10 +49,9 @@ const TYPE_DOUBLE_LITERAL: u8 = 10;
 const TYPE_INTEGER_LITERAL: u8 = 11;
 const TYPE_DECIMAL_LITERAL: u8 = 12;
 const TYPE_DATE_TIME_LITERAL: u8 = 13;
-const TYPE_NAIVE_DATE_TIME_LITERAL: u8 = 14;
-const TYPE_DATE_LITERAL: u8 = 15;
-const TYPE_NAIVE_DATE_LITERAL: u8 = 16;
-const TYPE_NAIVE_TIME_LITERAL: u8 = 17;
+const TYPE_DATE_LITERAL: u8 = 14;
+const TYPE_TIME_LITERAL: u8 = 15;
+const TYPE_DURATION_LITERAL: u8 = 16;
 
 pub const ENCODED_DEFAULT_GRAPH: EncodedTerm = EncodedTerm::DefaultGraph;
 pub const ENCODED_EMPTY_STRING_LITERAL: EncodedTerm = EncodedTerm::StringLiteral {
@@ -89,6 +87,9 @@ pub const ENCODED_XSD_TIME_NAMED_NODE: EncodedTerm = EncodedTerm::NamedNode {
 pub const ENCODED_XSD_DATE_TIME_NAMED_NODE: EncodedTerm = EncodedTerm::NamedNode {
     iri_id: XSD_DATE_TIME_ID,
 };
+pub const ENCODED_XSD_DURATION_NAMED_NODE: EncodedTerm = EncodedTerm::NamedNode {
+    iri_id: XSD_DURATION_ID,
+};
 
 #[derive(Debug, Clone, Copy)]
 pub enum EncodedTerm {
@@ -103,11 +104,10 @@ pub enum EncodedTerm {
     DoubleLiteral(f64),
     IntegerLiteral(i64),
     DecimalLiteral(Decimal),
-    DateLiteral(Date<FixedOffset>),
-    NaiveDateLiteral(NaiveDate),
-    NaiveTimeLiteral(NaiveTime),
-    DateTimeLiteral(DateTime<FixedOffset>),
-    NaiveDateTimeLiteral(NaiveDateTime),
+    DateLiteral(Date),
+    TimeLiteral(Time),
+    DateTimeLiteral(DateTime),
+    DurationLiteral(Duration),
 }
 
 impl PartialEq for EncodedTerm {
@@ -167,10 +167,9 @@ impl PartialEq for EncodedTerm {
             (EncodedTerm::IntegerLiteral(a), EncodedTerm::IntegerLiteral(b)) => a == b,
             (EncodedTerm::DecimalLiteral(a), EncodedTerm::DecimalLiteral(b)) => a == b,
             (EncodedTerm::DateLiteral(a), EncodedTerm::DateLiteral(b)) => a == b,
-            (EncodedTerm::NaiveDateLiteral(a), EncodedTerm::NaiveDateLiteral(b)) => a == b,
-            (EncodedTerm::NaiveTimeLiteral(a), EncodedTerm::NaiveTimeLiteral(b)) => a == b,
+            (EncodedTerm::TimeLiteral(a), EncodedTerm::TimeLiteral(b)) => a == b,
             (EncodedTerm::DateTimeLiteral(a), EncodedTerm::DateTimeLiteral(b)) => a == b,
-            (EncodedTerm::NaiveDateTimeLiteral(a), EncodedTerm::NaiveDateTimeLiteral(b)) => a == b,
+            (EncodedTerm::DurationLiteral(a), EncodedTerm::DurationLiteral(b)) => a == b,
             (_, _) => false,
         }
     }
@@ -205,10 +204,9 @@ impl Hash for EncodedTerm {
             EncodedTerm::IntegerLiteral(value) => value.hash(state),
             EncodedTerm::DecimalLiteral(value) => value.hash(state),
             EncodedTerm::DateLiteral(value) => value.hash(state),
-            EncodedTerm::NaiveDateLiteral(value) => value.hash(state),
-            EncodedTerm::NaiveTimeLiteral(value) => value.hash(state),
+            EncodedTerm::TimeLiteral(value) => value.hash(state),
             EncodedTerm::DateTimeLiteral(value) => value.hash(state),
-            EncodedTerm::NaiveDateTimeLiteral(value) => value.hash(state),
+            EncodedTerm::DurationLiteral(value) => value.hash(state),
         }
     }
 }
@@ -239,10 +237,9 @@ impl EncodedTerm {
             | EncodedTerm::IntegerLiteral(_)
             | EncodedTerm::DecimalLiteral(_)
             | EncodedTerm::DateLiteral(_)
-            | EncodedTerm::NaiveDateLiteral(_)
-            | EncodedTerm::NaiveTimeLiteral(_)
+            | EncodedTerm::TimeLiteral(_)
             | EncodedTerm::DateTimeLiteral(_)
-            | EncodedTerm::NaiveDateTimeLiteral(_) => true,
+            | EncodedTerm::DurationLiteral(_) => true,
             _ => false,
         }
     }
@@ -260,11 +257,9 @@ impl EncodedTerm {
             EncodedTerm::IntegerLiteral(..) => Some(ENCODED_XSD_INTEGER_NAMED_NODE),
             EncodedTerm::DecimalLiteral(..) => Some(ENCODED_XSD_DECIMAL_NAMED_NODE),
             EncodedTerm::DateLiteral(..) => Some(ENCODED_XSD_DATE_NAMED_NODE),
-            EncodedTerm::NaiveDateLiteral(..) => Some(ENCODED_XSD_DATE_NAMED_NODE),
-            EncodedTerm::NaiveTimeLiteral(..) => Some(ENCODED_XSD_TIME_NAMED_NODE),
-            EncodedTerm::DateTimeLiteral(..) | EncodedTerm::NaiveDateTimeLiteral(..) => {
-                Some(ENCODED_XSD_DATE_TIME_NAMED_NODE)
-            }
+            EncodedTerm::TimeLiteral(..) => Some(ENCODED_XSD_TIME_NAMED_NODE),
+            EncodedTerm::DateTimeLiteral(..) => Some(ENCODED_XSD_DATE_TIME_NAMED_NODE),
+            EncodedTerm::DurationLiteral(..) => Some(ENCODED_XSD_DURATION_NAMED_NODE),
             _ => None,
         }
     }
@@ -284,10 +279,9 @@ impl EncodedTerm {
             EncodedTerm::IntegerLiteral(_) => TYPE_INTEGER_LITERAL,
             EncodedTerm::DecimalLiteral(_) => TYPE_DECIMAL_LITERAL,
             EncodedTerm::DateLiteral(_) => TYPE_DATE_LITERAL,
-            EncodedTerm::NaiveDateLiteral(_) => TYPE_NAIVE_DATE_LITERAL,
-            EncodedTerm::NaiveTimeLiteral(_) => TYPE_NAIVE_TIME_LITERAL,
+            EncodedTerm::TimeLiteral(_) => TYPE_TIME_LITERAL,
             EncodedTerm::DateTimeLiteral(_) => TYPE_DATE_TIME_LITERAL,
-            EncodedTerm::NaiveDateTimeLiteral(_) => TYPE_NAIVE_DATE_TIME_LITERAL,
+            EncodedTerm::DurationLiteral(_) => TYPE_DURATION_LITERAL,
         }
     }
 }
@@ -316,6 +310,11 @@ impl From<u32> for EncodedTerm {
     }
 }
 
+impl From<u8> for EncodedTerm {
+    fn from(value: u8) -> Self {
+        EncodedTerm::IntegerLiteral(value.into())
+    }
+}
 impl From<f32> for EncodedTerm {
     fn from(value: f32) -> Self {
         EncodedTerm::FloatLiteral(value)
@@ -334,33 +333,27 @@ impl From<Decimal> for EncodedTerm {
     }
 }
 
-impl From<Date<FixedOffset>> for EncodedTerm {
-    fn from(value: Date<FixedOffset>) -> Self {
+impl From<Date> for EncodedTerm {
+    fn from(value: Date) -> Self {
         EncodedTerm::DateLiteral(value)
     }
 }
 
-impl From<NaiveDate> for EncodedTerm {
-    fn from(value: NaiveDate) -> Self {
-        EncodedTerm::NaiveDateLiteral(value)
-    }
-}
-
-impl From<NaiveTime> for EncodedTerm {
-    fn from(value: NaiveTime) -> Self {
-        EncodedTerm::NaiveTimeLiteral(value)
+impl From<Time> for EncodedTerm {
+    fn from(value: Time) -> Self {
+        EncodedTerm::TimeLiteral(value)
     }
 }
 
-impl From<DateTime<FixedOffset>> for EncodedTerm {
-    fn from(value: DateTime<FixedOffset>) -> Self {
+impl From<DateTime> for EncodedTerm {
+    fn from(value: DateTime) -> Self {
         EncodedTerm::DateTimeLiteral(value)
     }
 }
 
-impl From<NaiveDateTime> for EncodedTerm {
-    fn from(value: NaiveDateTime) -> Self {
-        EncodedTerm::NaiveDateTimeLiteral(value)
+impl From<Duration> for EncodedTerm {
+    fn from(value: Duration) -> Self {
+        EncodedTerm::DurationLiteral(value)
     }
 }
 
@@ -436,6 +429,11 @@ impl<'a> From<rio::Literal<'a>> for EncodedTerm {
                     | "http://www.w3.org/2001/XMLSchema#dateTimeStamp" => {
                         parse_date_time_str(value)
                     }
+                    "http://www.w3.org/2001/XMLSchema#duration"
+                    | "http://www.w3.org/2001/XMLSchema#yearMonthDuration"
+                    | "http://www.w3.org/2001/XMLSchema#dayTimeDuration" => {
+                        parse_duration_str(value)
+                    }
                     _ => None,
                 } {
                     Some(v) => v,
@@ -545,43 +543,34 @@ impl<R: Read> TermReader for R {
                 self.read_i64::<LittleEndian>()?,
             )),
             TYPE_DECIMAL_LITERAL => {
-                let mut buffer = [0 as u8; 16];
+                let mut buffer = [0; 16];
                 self.read_exact(&mut buffer)?;
                 Ok(EncodedTerm::DecimalLiteral(Decimal::from_le_bytes(buffer)))
             }
-            TYPE_DATE_LITERAL => Ok(EncodedTerm::DateLiteral(Date::from_utc(
-                NaiveDate::from_num_days_from_ce_opt(self.read_i32::<LittleEndian>()?)
-                    .ok_or_else(|| format_err!("Invalid date serialization"))?,
-                FixedOffset::east_opt(self.read_i32::<LittleEndian>()?)
-                    .ok_or_else(|| format_err!("Invalid timezone offset"))?,
-            ))),
-            TYPE_NAIVE_DATE_LITERAL => Ok(EncodedTerm::NaiveDateLiteral(
-                NaiveDate::from_num_days_from_ce_opt(self.read_i32::<LittleEndian>()?)
-                    .ok_or_else(|| format_err!("Invalid date serialization"))?,
-            )),
-            TYPE_NAIVE_TIME_LITERAL => Ok(EncodedTerm::NaiveTimeLiteral(
-                NaiveTime::from_num_seconds_from_midnight_opt(
-                    self.read_u32::<LittleEndian>()?,
-                    self.read_u32::<LittleEndian>()?,
-                )
-                .ok_or_else(|| format_err!("Invalid time serialization"))?,
-            )),
-            TYPE_DATE_TIME_LITERAL => Ok(EncodedTerm::DateTimeLiteral(DateTime::from_utc(
-                NaiveDateTime::from_timestamp_opt(
-                    self.read_i64::<LittleEndian>()?,
-                    self.read_u32::<LittleEndian>()?,
-                )
-                .ok_or_else(|| format_err!("Invalid date time serialization"))?,
-                FixedOffset::east_opt(self.read_i32::<LittleEndian>()?)
-                    .ok_or_else(|| format_err!("Invalid timezone offset"))?,
-            ))),
-            TYPE_NAIVE_DATE_TIME_LITERAL => Ok(EncodedTerm::NaiveDateTimeLiteral(
-                NaiveDateTime::from_timestamp_opt(
-                    self.read_i64::<LittleEndian>()?,
-                    self.read_u32::<LittleEndian>()?,
-                )
-                .ok_or_else(|| format_err!("Invalid date time serialization"))?,
-            )),
+            TYPE_DATE_LITERAL => {
+                let mut buffer = [0; 18];
+                self.read_exact(&mut buffer)?;
+                Ok(EncodedTerm::DateLiteral(Date::from_le_bytes(buffer)))
+            }
+            TYPE_TIME_LITERAL => {
+                let mut buffer = [0; 18];
+                self.read_exact(&mut buffer)?;
+                Ok(EncodedTerm::TimeLiteral(Time::from_le_bytes(buffer)))
+            }
+            TYPE_DATE_TIME_LITERAL => {
+                let mut buffer = [0; 18];
+                self.read_exact(&mut buffer)?;
+                Ok(EncodedTerm::DateTimeLiteral(DateTime::from_le_bytes(
+                    buffer,
+                )))
+            }
+            TYPE_DURATION_LITERAL => {
+                let mut buffer = [0; 24];
+                self.read_exact(&mut buffer)?;
+                Ok(EncodedTerm::DurationLiteral(Duration::from_le_bytes(
+                    buffer,
+                )))
+            }
             _ => Err(format_err!("the term buffer has an invalid type id")),
         }
     }
@@ -704,26 +693,10 @@ impl<W: Write> TermWriter for W {
             EncodedTerm::DoubleLiteral(value) => self.write_all(&value.to_le_bytes())?,
             EncodedTerm::IntegerLiteral(value) => self.write_all(&value.to_le_bytes())?,
             EncodedTerm::DecimalLiteral(value) => self.write_all(&value.to_le_bytes())?,
-            EncodedTerm::DateLiteral(value) => {
-                self.write_all(&value.num_days_from_ce().to_le_bytes())?;
-                self.write_all(&value.timezone().local_minus_utc().to_le_bytes())?;
-            }
-            EncodedTerm::NaiveDateLiteral(value) => {
-                self.write_all(&value.num_days_from_ce().to_le_bytes())?
-            }
-            EncodedTerm::NaiveTimeLiteral(value) => {
-                self.write_all(&value.num_seconds_from_midnight().to_le_bytes())?;
-                self.write_all(&value.nanosecond().to_le_bytes())?;
-            }
-            EncodedTerm::DateTimeLiteral(value) => {
-                self.write_all(&value.timestamp().to_le_bytes())?;
-                self.write_all(&value.timestamp_subsec_nanos().to_le_bytes())?;
-                self.write_all(&value.timezone().local_minus_utc().to_le_bytes())?;
-            }
-            EncodedTerm::NaiveDateTimeLiteral(value) => {
-                self.write_all(&value.timestamp().to_le_bytes())?;
-                self.write_all(&value.timestamp_subsec_nanos().to_le_bytes())?;
-            }
+            EncodedTerm::DateLiteral(value) => self.write_all(&value.to_le_bytes())?,
+            EncodedTerm::TimeLiteral(value) => self.write_all(&value.to_le_bytes())?,
+            EncodedTerm::DateTimeLiteral(value) => self.write_all(&value.to_le_bytes())?,
+            EncodedTerm::DurationLiteral(value) => self.write_all(&value.to_le_bytes())?,
         }
         Ok(())
     }
@@ -797,6 +770,7 @@ pub trait StrContainer {
         self.insert_str(XSD_DATE_TIME_ID, xsd::DATE_TIME.as_str())?;
         self.insert_str(XSD_DATE_ID, xsd::DATE.as_str())?;
         self.insert_str(XSD_TIME_ID, xsd::TIME.as_str())?;
+        self.insert_str(XSD_DURATION_ID, xsd::DURATION.as_str())?;
         Ok(())
     }
 }
@@ -1028,6 +1002,11 @@ impl<S: StrContainer> Encoder for S {
                     | "http://www.w3.org/2001/XMLSchema#dateTimeStamp" => {
                         parse_date_time_str(value)
                     }
+                    "http://www.w3.org/2001/XMLSchema#duration"
+                    | "http://www.w3.org/2001/XMLSchema#yearMonthDuration"
+                    | "http://www.w3.org/2001/XMLSchema#dayTimeDuration" => {
+                        parse_duration_str(value)
+                    }
                     _ => None,
                 } {
                     Some(v) => v,
@@ -1072,39 +1051,19 @@ pub fn parse_decimal_str(value: &str) -> Option<EncodedTerm> {
 }
 
 pub fn parse_date_str(value: &str) -> Option<EncodedTerm> {
-    let mut parsed = Parsed::new();
-    match parse(&mut parsed, &value, StrftimeItems::new("%Y-%m-%d%:z")).and_then(|_| {
-        Ok(Date::from_utc(
-            parsed.to_naive_date()?,
-            parsed.to_fixed_offset()?,
-        ))
-    }) {
-        Ok(value) => Some(EncodedTerm::DateLiteral(value)),
-        Err(_) => match NaiveDate::parse_from_str(&value, "%Y-%m-%dZ") {
-            Ok(value) => Some(EncodedTerm::DateLiteral(Date::from_utc(
-                value,
-                FixedOffset::east(0),
-            ))),
-            Err(_) => NaiveDate::parse_from_str(&value, "%Y-%m-%d")
-                .map(EncodedTerm::NaiveDateLiteral)
-                .ok(),
-        },
-    }
+    value.parse().map(EncodedTerm::DateLiteral).ok()
 }
 
 pub fn parse_time_str(value: &str) -> Option<EncodedTerm> {
-    NaiveTime::parse_from_str(&value, "%H:%M:%S")
-        .map(EncodedTerm::NaiveTimeLiteral)
-        .ok()
+    value.parse().map(EncodedTerm::TimeLiteral).ok()
 }
 
 pub fn parse_date_time_str(value: &str) -> Option<EncodedTerm> {
-    match DateTime::parse_from_rfc3339(&value) {
-        Ok(value) => Some(EncodedTerm::DateTimeLiteral(value)),
-        Err(_) => NaiveDateTime::parse_from_str(&value, "%Y-%m-%dT%H:%M:%S")
-            .map(EncodedTerm::NaiveDateTimeLiteral)
-            .ok(),
-    }
+    value.parse().map(EncodedTerm::DateTimeLiteral).ok()
+}
+
+pub fn parse_duration_str(value: &str) -> Option<EncodedTerm> {
+    value.parse().map(EncodedTerm::DurationLiteral).ok()
 }
 
 pub trait Decoder {
@@ -1188,10 +1147,9 @@ impl<S: StrLookup> Decoder for S {
             EncodedTerm::IntegerLiteral(value) => Ok(Literal::from(value).into()),
             EncodedTerm::DecimalLiteral(value) => Ok(Literal::from(value).into()),
             EncodedTerm::DateLiteral(value) => Ok(Literal::from(value).into()),
-            EncodedTerm::NaiveDateLiteral(value) => Ok(Literal::from(value).into()),
-            EncodedTerm::NaiveTimeLiteral(value) => Ok(Literal::from(value).into()),
+            EncodedTerm::TimeLiteral(value) => Ok(Literal::from(value).into()),
             EncodedTerm::DateTimeLiteral(value) => Ok(Literal::from(value).into()),
-            EncodedTerm::NaiveDateTimeLiteral(value) => Ok(Literal::from(value).into()),
+            EncodedTerm::DurationLiteral(value) => Ok(Literal::from(value).into()),
         }
     }
 }
diff --git a/lib/tests/sparql_test_cases.rs b/lib/tests/sparql_test_cases.rs
index 4c71a7a6..96baa295 100644
--- a/lib/tests/sparql_test_cases.rs
+++ b/lib/tests/sparql_test_cases.rs
@@ -133,6 +133,8 @@ fn sparql_w3c_query_evaluation_testsuite() -> Result<()> {
         NamedNode::parse("http://www.w3.org/2009/sparql/docs/tests/data-sparql11/property-path/manifest#pp35").unwrap(),
         //SERVICE name from a BGP
         NamedNode::parse("http://www.w3.org/2009/sparql/docs/tests/data-sparql11/service/manifest#service5").unwrap(),
+        // We use XSD 1.1 equality on dates
+        NamedNode::parse("http://www.w3.org/2001/sw/DataAccess/tests/data-r2/open-world/manifest#date-2").unwrap(),
 
     ];