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/* Copyright (c) 2006, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* ---
* Author: Mike Burrows
*/
#if !defined(_BASE_LOW_LEVEL_ALLOC_H_)
#define _BASE_LOW_LEVEL_ALLOC_H_
// A simple memory allocator that does not depend on mutexes or
// thread-specific data. It is intended to be used sparingly,
// and only when malloc() would introduce an unwanted dependency,
// such as inside the heap-checker.
#include <stddef.h> // for size_t
#include "base/basictypes.h"
class LowLevelAlloc {
public:
struct Arena; // an arena from which memory may be allocated
// Returns a pointer to a block of at least "request" bytes
// that have been newly allocated from the specific arena.
// The arena may be 0, in which case a default arena is used.
// Returns 0 if passed request==0.
// Does not return 0 under other circumstances; it crashes if memory
// is not available.
static void *Alloc(size_t request, Arena *arena)
ATTRIBUTE_SECTION(malloc_hook_callers);
// Deallocates a region of memory that was previously allocated with
// Alloc(). Does nothing if passed 0. "s" must be either 0,
// or must have been returned from a call to Alloc() and not yet passed to
// Free() since that call to Alloc(). The space is returned to the arena
// from which it was allocated.
static void Free(void *s) ATTRIBUTE_SECTION(malloc_hook_callers);
// ATTRIBUTE_SECTION(malloc_hook_callers) for Alloc and Free
// are to put all callers of MallocHook::Invoke* in this module
// into special section,
// so that MallocHook::GetCallerStackTrace can function accurately.
// Create a new arena.
// The root metadata for the new arena is allocated in the
// meta_data_arena; the default arena is used if meta_data_arena==0.
// These values may be ored into flags:
enum { kCallMallocHook = 0x0001 }; // calls to Alloc() and Free()
// will be reported via the MallocHook
// interface.
static Arena *NewArena(int32 flags, Arena *meta_data_arena);
// Destroys an arena allocated by NewArena and returns true,
// provided no allocated blocks remain in the arena.
// If allocated blocks remain in the arena, does nothing and
// returns false.
// It is illegal to attempt to destroy the default arena.
static bool DeleteArena(Arena *arena);
private:
LowLevelAlloc(); // no instances
};
#endif
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