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/* builder.h */
/* Copyright 2009 10gen Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include "../stdafx.h"
namespace mongo {
class BufBuilder {
public:
BufBuilder(int initsize = 512) : size(initsize) {
if ( size > 0 ) {
data = (char *) malloc(size);
assert(data);
} else {
data = 0;
}
l = 0;
}
~BufBuilder() {
kill();
}
void kill() {
if ( data ) {
free(data);
data = 0;
}
}
/* leave room for some stuff later */
void skip(int n) {
grow(n);
}
/* note this may be deallocated (realloced) if you keep writing. */
char* buf() {
return data;
}
/* assume ownership of the buffer - you must then free it */
void decouple() {
data = 0;
}
template<class T> void append(T j) {
*((T*)grow(sizeof(T))) = j;
}
void append(short j) {
append<short>(j);
}
void append(int j) {
append<int>(j);
}
void append(unsigned j) {
append<unsigned>(j);
}
void append(bool j) {
append<bool>(j);
}
void append(double j) {
append<double>(j);
}
void append(const void *src, int len) {
memcpy(grow(len), src, len);
}
void append(const char *str) {
append((void*) str, strlen(str)+1);
}
void append(const string &str) {
append( (void *)str.c_str(), str.length() + 1 );
}
int len() const {
return l;
}
void setlen( int newLen ){
l = newLen;
}
private:
/* returns the pre-grow write position */
char* grow(int by) {
int oldlen = l;
l += by;
if ( l > size ) {
int a = size * 2;
if ( a == 0 )
a = 512;
if ( l > a )
a = l + 16 * 1024;
assert( a < 64 * 1024 * 1024 );
data = (char *) realloc(data, a);
size= a;
}
return data + oldlen;
}
char *data;
int l;
int size;
};
} // namespace mongo
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