Coding.h: Added Fixed16 support (#4142)

Summary:
Added Get Put Encode Decode support for Fixed16 (uint16_t). Unit test added in `coding_test.cc`
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4142

Differential Revision: D8873516

Pulled By: fgwu

fbshipit-source-id: 331913e0a9a8fe9c95606a08e856e953477d64d3
main
Fenggang Wu 6 years ago committed by Facebook Github Bot
parent fb768a4289
commit 5a59ce4149
  1. 44
      util/coding.h
  2. 13
      util/coding_test.cc

@ -32,6 +32,7 @@ namespace rocksdb {
const unsigned int kMaxVarint64Length = 10;
// Standard Put... routines append to a string
extern void PutFixed16(std::string* dst, uint16_t value);
extern void PutFixed32(std::string* dst, uint32_t value);
extern void PutFixed64(std::string* dst, uint64_t value);
extern void PutVarint32(std::string* dst, uint32_t value);
@ -54,6 +55,7 @@ extern void PutLengthPrefixedSliceParts(std::string* dst,
// and advance the slice past the parsed value.
extern bool GetFixed64(Slice* input, uint64_t* value);
extern bool GetFixed32(Slice* input, uint32_t* value);
extern bool GetFixed16(Slice* input, uint16_t* value);
extern bool GetVarint32(Slice* input, uint32_t* value);
extern bool GetVarint64(Slice* input, uint64_t* value);
extern bool GetLengthPrefixedSlice(Slice* input, Slice* result);
@ -74,6 +76,7 @@ extern int VarintLength(uint64_t v);
// Lower-level versions of Put... that write directly into a character buffer
// REQUIRES: dst has enough space for the value being written
extern void EncodeFixed16(char* dst, uint16_t value);
extern void EncodeFixed32(char* dst, uint32_t value);
extern void EncodeFixed64(char* dst, uint64_t value);
@ -86,6 +89,18 @@ extern char* EncodeVarint64(char* dst, uint64_t value);
// Lower-level versions of Get... that read directly from a character buffer
// without any bounds checking.
inline uint16_t DecodeFixed16(const char* ptr) {
if (port::kLittleEndian) {
// Load the raw bytes
uint16_t result;
memcpy(&result, ptr, sizeof(result)); // gcc optimizes this to a plain load
return result;
} else {
return ((static_cast<uint16_t>(static_cast<unsigned char>(ptr[0]))) |
(static_cast<uint16_t>(static_cast<unsigned char>(ptr[1])) << 8));
}
}
inline uint32_t DecodeFixed32(const char* ptr) {
if (port::kLittleEndian) {
// Load the raw bytes
@ -131,6 +146,15 @@ inline const char* GetVarint32Ptr(const char* p,
}
// -- Implementation of the functions declared above
inline void EncodeFixed16(char* buf, uint16_t value) {
if (port::kLittleEndian) {
memcpy(buf, &value, sizeof(value));
} else {
buf[0] = value & 0xff;
buf[1] = (value >> 8) & 0xff;
}
}
inline void EncodeFixed32(char* buf, uint32_t value) {
if (port::kLittleEndian) {
memcpy(buf, &value, sizeof(value));
@ -158,6 +182,17 @@ inline void EncodeFixed64(char* buf, uint64_t value) {
}
// Pull the last 8 bits and cast it to a character
inline void PutFixed16(std::string* dst, uint16_t value) {
if (port::kLittleEndian) {
dst->append(const_cast<const char*>(reinterpret_cast<char*>(&value)),
sizeof(value));
} else {
char buf[sizeof(value)];
EncodeFixed16(buf, value);
dst->append(buf, sizeof(buf));
}
}
inline void PutFixed32(std::string* dst, uint32_t value) {
if (port::kLittleEndian) {
dst->append(const_cast<const char*>(reinterpret_cast<char*>(&value)),
@ -286,6 +321,15 @@ inline bool GetFixed32(Slice* input, uint32_t* value) {
return true;
}
inline bool GetFixed16(Slice* input, uint16_t* value) {
if (input->size() < sizeof(uint16_t)) {
return false;
}
*value = DecodeFixed16(input->data());
input->remove_prefix(sizeof(uint16_t));
return true;
}
inline bool GetVarint32(Slice* input, uint32_t* value) {
const char* p = input->data();
const char* limit = p + input->size();

@ -14,6 +14,19 @@
namespace rocksdb {
class Coding { };
TEST(Coding, Fixed16) {
std::string s;
for (uint16_t v = 0; v < 0xFFFF; v++) {
PutFixed16(&s, v);
}
const char* p = s.data();
for (uint16_t v = 0; v < 0xFFFF; v++) {
uint16_t actual = DecodeFixed16(p);
ASSERT_EQ(v, actual);
p += sizeof(uint16_t);
}
}
TEST(Coding, Fixed32) {
std::string s;

Loading…
Cancel
Save