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mongodb/util/alignedbuilder.cpp

99 lines
2.8 KiB
C++

// @file alignedbuilder.cpp
/**
* 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/>.
*/
#if defined(_WIN32)
#include <windows.h>
#endif
#include "alignedbuilder.h"
#include "assert.h"
#include "../bson/inline_decls.h"
namespace mongo {
AlignedBuilder::AlignedBuilder(unsigned init_size) : _size(init_size) {
_data = (char *) _malloc(_size);
if( _data == 0 )
throw std::exception("out of memory AlignedBuilder");
_len = 0;
}
void* AlignedBuilder::mallocSelfAligned(unsigned sz) {
void *p = malloc(sz + Alignment - 1);
_realAddr = p;
size_t s = (size_t) p;
s += Alignment - 1;
s = (s/Alignment)*Alignment;
return (void*) s;
}
/* "slow"/infrequent portion of 'grow()' */
void NOINLINE_DECL AlignedBuilder::grow_reallocate() {
unsigned a = _size * 2;
assert( a );
if ( _len > a )
a = _len + 16 * 1024;
assert( a < 0x20000000 );
_data = (char *) _realloc(_data, a, _len);
_size = a;
}
void* AlignedBuilder::_malloc(unsigned sz) {
#if defined(_WIN32)
void *p = VirtualAlloc(0, sz, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
_realAddr = p;
//#elif defined(_POSIX_VERSION)
// in theory _POSIX_VERSION should work, but it doesn't on OS X 10.4, and needs to be testeed on solaris.
// so for now, linux only for this.
#elif defined(__linux__)
void *p = 0;
int res = posix_memalign(&p, Alignment, sz);
massert(13524, "out of memory AlignedBuilder", res == 0);
_realAddr = p;
#else
void *p = mallocSelfAligned(sz);
assert( ((size_t) p) % Alignment == 0 );
#endif
return p;
}
void* AlignedBuilder::_realloc(void *ptr, unsigned newSize, unsigned oldSize) {
// posix_memalign alignment is not maintained on reallocs
void *oldAddr = _realAddr;
void *p = _malloc(newSize);
memcpy(p, ptr, oldSize);
_free(oldAddr);
return p;
}
void AlignedBuilder::_free(void *p) {
#if defined(_WIN32)
VirtualFree(p, 0, MEM_RELEASE);
#else
free(p);
#endif
}
void AlignedBuilder::kill() {
_free(_realAddr);
_data = 0;
_realAddr = 0;
}
}