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// @file alignedbuilder.h
/**
* Copyright (C) 2009 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include "../bson/stringdata.h"
namespace mongo {
/** a page-aligned BufBuilder. */
class AlignedBuilder {
public:
AlignedBuilder(unsigned init_size);
~AlignedBuilder() { kill(); }
/** reset with a hint as to the upcoming needed size specified */
void reset(unsigned sz);
/** reset for a re-use. shrinks if > 128MB */
void reset();
/** note this may be deallocated (realloced) if you keep writing or reset(). */
const char* buf() const { return _p._data; }
/** leave room for some stuff later
@return offset in the buffer that was our current position
*/
size_t skip(unsigned n) {
unsigned l = len();
grow(n);
return l;
}
/** if buffer grows pointer no longer valid */
char* atOfs(unsigned ofs) { return _p._data + ofs; }
/** if buffer grows pointer no longer valid */
char* cur() { return _p._data + _len; }
void appendChar(char j) {
*((char*)grow(sizeof(char))) = j;
}
void appendNum(char j) {
*((char*)grow(sizeof(char))) = j;
}
void appendNum(short j) {
*((short*)grow(sizeof(short))) = j;
}
void appendNum(int j) {
*((int*)grow(sizeof(int))) = j;
}
void appendNum(unsigned j) {
*((unsigned*)grow(sizeof(unsigned))) = j;
}
void appendNum(bool j) {
*((bool*)grow(sizeof(bool))) = j;
}
void appendNum(double j) {
*((double*)grow(sizeof(double))) = j;
}
void appendNum(long long j) {
*((long long*)grow(sizeof(long long))) = j;
}
void appendNum(unsigned long long j) {
*((unsigned long long*)grow(sizeof(unsigned long long))) = j;
}
void appendBuf(const void *src, size_t len) { memcpy(grow((unsigned) len), src, len); }
template<class T>
void appendStruct(const T& s) { appendBuf(&s, sizeof(T)); }
void appendStr(const StringData &str , bool includeEOO = true ) {
const unsigned len = str.size() + ( includeEOO ? 1 : 0 );
assert( len < (unsigned) BSONObjMaxUserSize );
memcpy(grow(len), str.data(), len);
}
/** @return the in-use length */
unsigned len() const { return _len; }
private:
static const unsigned Alignment = 8192;
/** returns the pre-grow write position */
inline char* grow(unsigned by) {
unsigned oldlen = _len;
_len += by;
if (MONGO_unlikely( _len > _p._size )) {
growReallocate(oldlen);
}
return _p._data + oldlen;
}
void growReallocate(unsigned oldLenInUse);
void kill();
void mallocSelfAligned(unsigned sz);
void _malloc(unsigned sz);
void _realloc(unsigned newSize, unsigned oldLenInUse);
void _free(void*);
struct AllocationInfo {
char *_data;
void *_allocationAddress;
unsigned _size;
} _p;
unsigned _len; // bytes in use
};
}
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