fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
58 lines
1.5 KiB
58 lines
1.5 KiB
![]()
11 years ago
|
/**
|
||
|
* A MergeOperator for rocksdb/leveldb that implements string append.
|
||
|
* @author Deon Nicholas (dnicholas@fb.com)
|
||
|
* Copyright 2013 Facebook
|
||
|
*/
|
||
|
|
||
|
#include "stringappend.h"
|
||
|
|
||
|
#include <memory>
|
||
|
#include <assert.h>
|
||
|
#include "leveldb/slice.h"
|
||
|
#include "leveldb/merge_operator.h"
|
||
|
#include "utilities/merge_operators.h"
|
||
|
#include <iostream>
|
||
|
|
||
|
namespace leveldb {
|
||
|
|
||
|
|
||
|
// Constructor: also specify the delimiter character.
|
||
|
StringAppendOperator::StringAppendOperator(char delim_char)
|
||
|
: delim_(delim_char) {
|
||
|
}
|
||
|
|
||
|
// Implementation for the merge operation (concatenates two strings)
|
||
|
void StringAppendOperator::Merge(const Slice& key,
|
||
|
const Slice* existing_value,
|
||
|
const Slice& value,
|
||
|
std::string* new_value,
|
||
|
Logger* logger) const {
|
||
|
|
||
|
// Clear the *new_value for writing.
|
||
|
assert(new_value);
|
||
|
new_value->clear();
|
||
|
|
||
|
if (!existing_value) {
|
||
|
// No existing_value. Set *new_value = value
|
||
|
new_value->assign(value.data(),value.size());
|
||
|
} else {
|
||
|
// Generic append (existing_value != null).
|
||
|
// Reserve *new_value to correct size, and apply concatenation.
|
||
|
new_value->reserve(existing_value->size() + 1 + value.size());
|
||
|
new_value->assign(existing_value->data(),existing_value->size());
|
||
|
new_value->append(1,delim_);
|
||
|
new_value->append(value.data(), value.size());
|
||
|
}
|
||
|
|
||
|
return;
|
||
|
}
|
||
|
|
||
|
const char* StringAppendOperator::Name() const {
|
||
|
return "StringAppendOperator";
|
||
|
}
|
||
|
|
||
|
} // namespace leveldb
|
||
|
|
||
|
|
||
|
|