| /************************************************************************** |
| * |
| * 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; |
| } |
| } |
| }; |
| |
| |