/usr/include/mongo/bson/util/builder.h is in mongodb-dev 1:2.4.9-1ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 | /* 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 <cfloat>
#include <iostream>
#include <sstream>
#include <stdio.h>
#include <string>
#include <string.h>
#include "mongo/bson/inline_decls.h"
#include "mongo/base/string_data.h"
#include "mongo/util/assert_util.h"
namespace mongo {
/* Accessing unaligned doubles on ARM generates an alignment trap and aborts with SIGBUS on Linux.
Wrapping the double in a packed struct forces gcc to generate code that works with unaligned values too.
The generated code for other architectures (which already allow unaligned accesses) is the same as if
there was a direct pointer access.
*/
struct PackedDouble {
double d;
} PACKED_DECL;
/* Note the limit here is rather arbitrary and is simply a standard. generally the code works
with any object that fits in ram.
Also note that the server has some basic checks to enforce this limit but those checks are not exhaustive
for example need to check for size too big after
update $push (append) operation
various db.eval() type operations
*/
const int BSONObjMaxUserSize = 16 * 1024 * 1024;
/*
Sometimes we need objects slightly larger - an object in the replication local.oplog
is slightly larger than a user object for example.
*/
const int BSONObjMaxInternalSize = BSONObjMaxUserSize + ( 16 * 1024 );
const int BufferMaxSize = 64 * 1024 * 1024;
void msgasserted(int msgid, const char *msg);
template <typename Allocator>
class StringBuilderImpl;
class TrivialAllocator {
public:
void* Malloc(size_t sz) { return malloc(sz); }
void* Realloc(void *p, size_t sz) { return realloc(p, sz); }
void Free(void *p) { free(p); }
};
class StackAllocator {
public:
enum { SZ = 512 };
void* Malloc(size_t sz) {
if( sz <= SZ ) return buf;
return malloc(sz);
}
void* Realloc(void *p, size_t sz) {
if( p == buf ) {
if( sz <= SZ ) return buf;
void *d = malloc(sz);
if ( d == 0 )
msgasserted( 15912 , "out of memory StackAllocator::Realloc" );
memcpy(d, p, SZ);
return d;
}
return realloc(p, sz);
}
void Free(void *p) {
if( p != buf )
free(p);
}
private:
char buf[SZ];
};
template< class Allocator >
class _BufBuilder {
// non-copyable, non-assignable
_BufBuilder( const _BufBuilder& );
_BufBuilder& operator=( const _BufBuilder& );
Allocator al;
public:
_BufBuilder(int initsize = 512) : size(initsize) {
if ( size > 0 ) {
data = (char *) al.Malloc(size);
if( data == 0 )
msgasserted(10000, "out of memory BufBuilder");
}
else {
data = 0;
}
l = 0;
}
~_BufBuilder() { kill(); }
void kill() {
if ( data ) {
al.Free(data);
data = 0;
}
}
void reset() {
l = 0;
}
void reset( int maxSize ) {
l = 0;
if ( maxSize && size > maxSize ) {
al.Free(data);
data = (char*)al.Malloc(maxSize);
if ( data == 0 )
msgasserted( 15913 , "out of memory BufBuilder::reset" );
size = maxSize;
}
}
/** leave room for some stuff later
@return point to region that was skipped. pointer may change later (on realloc), so for immediate use only
*/
char* skip(int n) { return grow(n); }
/* note this may be deallocated (realloced) if you keep writing. */
char* buf() { return data; }
const char* buf() const { return data; }
/* assume ownership of the buffer - you must then free() it */
void decouple() { data = 0; }
void appendUChar(unsigned char j) {
*((unsigned char*)grow(sizeof(unsigned char))) = j;
}
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) {
(reinterpret_cast< PackedDouble* >(grow(sizeof(double))))->d = 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((int) len), src, len);
}
template<class T>
void appendStruct(const T& s) {
appendBuf(&s, sizeof(T));
}
void appendStr(const StringData &str , bool includeEndingNull = true ) {
const int len = str.size() + ( includeEndingNull ? 1 : 0 );
str.copyTo( grow(len), includeEndingNull );
}
/** @return length of current string */
int len() const { return l; }
void setlen( int newLen ) { l = newLen; }
/** @return size of the buffer */
int getSize() const { return size; }
/* returns the pre-grow write position */
inline char* grow(int by) {
int oldlen = l;
int newLen = l + by;
if ( newLen > size ) {
grow_reallocate(newLen);
}
l = newLen;
return data + oldlen;
}
private:
/* "slow" portion of 'grow()' */
void NOINLINE_DECL grow_reallocate(int newLen) {
int a = 64;
while( a < newLen )
a = a * 2;
if ( a > BufferMaxSize ) {
std::stringstream ss;
ss << "BufBuilder attempted to grow() to " << a << " bytes, past the 64MB limit.";
msgasserted(13548, ss.str().c_str());
}
data = (char *) al.Realloc(data, a);
if ( data == NULL )
msgasserted( 16070 , "out of memory BufBuilder::grow_reallocate" );
size = a;
}
char *data;
int l;
int size;
friend class StringBuilderImpl<Allocator>;
};
typedef _BufBuilder<TrivialAllocator> BufBuilder;
/** The StackBufBuilder builds smaller datasets on the stack instead of using malloc.
this can be significantly faster for small bufs. However, you can not decouple() the
buffer with StackBufBuilder.
While designed to be a variable on the stack, if you were to dynamically allocate one,
nothing bad would happen. In fact in some circumstances this might make sense, say,
embedded in some other object.
*/
class StackBufBuilder : public _BufBuilder<StackAllocator> {
public:
StackBufBuilder() : _BufBuilder<StackAllocator>(StackAllocator::SZ) { }
void decouple(); // not allowed. not implemented.
};
#if defined(_WIN32)
#pragma push_macro("snprintf")
#define snprintf _snprintf
#endif
/** stringstream deals with locale so this is a lot faster than std::stringstream for UTF8 */
template <typename Allocator>
class StringBuilderImpl {
public:
static const size_t MONGO_DBL_SIZE = 3 + DBL_MANT_DIG - DBL_MIN_EXP;
static const size_t MONGO_S32_SIZE = 12;
static const size_t MONGO_U32_SIZE = 11;
static const size_t MONGO_S64_SIZE = 23;
static const size_t MONGO_U64_SIZE = 22;
static const size_t MONGO_S16_SIZE = 7;
StringBuilderImpl() { }
StringBuilderImpl& operator<<( double x ) {
return SBNUM( x , MONGO_DBL_SIZE , "%g" );
}
StringBuilderImpl& operator<<( int x ) {
return SBNUM( x , MONGO_S32_SIZE , "%d" );
}
StringBuilderImpl& operator<<( unsigned x ) {
return SBNUM( x , MONGO_U32_SIZE , "%u" );
}
StringBuilderImpl& operator<<( long x ) {
return SBNUM( x , MONGO_S64_SIZE , "%ld" );
}
StringBuilderImpl& operator<<( unsigned long x ) {
return SBNUM( x , MONGO_U64_SIZE , "%lu" );
}
StringBuilderImpl& operator<<( long long x ) {
return SBNUM( x , MONGO_S64_SIZE , "%lld" );
}
StringBuilderImpl& operator<<( unsigned long long x ) {
return SBNUM( x , MONGO_U64_SIZE , "%llu" );
}
StringBuilderImpl& operator<<( short x ) {
return SBNUM( x , MONGO_S16_SIZE , "%hd" );
}
StringBuilderImpl& operator<<( char c ) {
_buf.grow( 1 )[0] = c;
return *this;
}
void appendDoubleNice( double x ) {
const int prev = _buf.l;
const int maxSize = 32;
char * start = _buf.grow( maxSize );
int z = snprintf( start , maxSize , "%.16g" , x );
verify( z >= 0 );
verify( z < maxSize );
_buf.l = prev + z;
if( strchr(start, '.') == 0 && strchr(start, 'E') == 0 && strchr(start, 'N') == 0 ) {
write( ".0" , 2 );
}
}
void write( const char* buf, int len) { memcpy( _buf.grow( len ) , buf , len ); }
void append( const StringData& str ) { str.copyTo( _buf.grow( str.size() ), false ); }
StringBuilderImpl& operator<<( const StringData& str ) {
append( str );
return *this;
}
void reset( int maxSize = 0 ) { _buf.reset( maxSize ); }
std::string str() const { return std::string(_buf.data, _buf.l); }
/** size of current string */
int len() const { return _buf.l; }
private:
_BufBuilder<Allocator> _buf;
// non-copyable, non-assignable
StringBuilderImpl( const StringBuilderImpl& );
StringBuilderImpl& operator=( const StringBuilderImpl& );
template <typename T>
StringBuilderImpl& SBNUM(T val,int maxSize,const char *macro) {
int prev = _buf.l;
int z = snprintf( _buf.grow(maxSize) , maxSize , macro , (val) );
verify( z >= 0 );
verify( z < maxSize );
_buf.l = prev + z;
return *this;
}
};
typedef StringBuilderImpl<TrivialAllocator> StringBuilder;
typedef StringBuilderImpl<StackAllocator> StackStringBuilder;
#if defined(_WIN32)
#undef snprintf
#pragma pop_macro("snprintf")
#endif
} // namespace mongo
|