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/**************************************************************************
*
* Copyright 2011-2012 Jose Fonseca
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
**************************************************************************/
#pragma once
#include <assert.h>
#include <stdint.h>
#include <stdlib.h>
#include <algorithm>
/**
* Similar to alloca(), but implemented with malloc.
*/
class ScopedAllocator
{
private:
uintptr_t next;
public:
inline
ScopedAllocator() :
next(0) {
}
inline void *
alloc(size_t size) {
/* Always return valid address, even when size is zero */
size = std::max(size, sizeof(uintptr_t));
uintptr_t * buf = static_cast<uintptr_t *>(malloc(sizeof(uintptr_t) + size));
if (!buf) {
return NULL;
}
*buf = next;
next = reinterpret_cast<uintptr_t>(buf);
assert((next & 1) == 0);
return static_cast<void *>(&buf[1]);
}
/* XXX: See comment in retrace::ScopedAllocator::allocArray template. */
template< class T >
inline T *
alloc(size_t size = 1, size_t sizeof_T = sizeof(T)) {
return static_cast<T *>(alloc(sizeof_T * size));
}
/**
* Prevent this pointer from being automatically freed.
*/
template< class T >
inline void
bind(T *ptr) {
if (ptr) {
reinterpret_cast<uintptr_t *>(ptr)[-1] |= 1;
}
}
inline
~ScopedAllocator() {
while (next) {
uintptr_t temp = *reinterpret_cast<uintptr_t *>(next);
bool bind = temp & 1;
temp &= ~1;
if (!bind) {
free(reinterpret_cast<void *>(next));
}
next = temp;
}
}
};
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