1cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project/* 2cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project * Copyright (C) 2005 The Android Open Source Project 3cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project * 4cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project * Licensed under the Apache License, Version 2.0 (the "License"); 5cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project * you may not use this file except in compliance with the License. 6cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project * You may obtain a copy of the License at 7cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project * 8cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project * http://www.apache.org/licenses/LICENSE-2.0 9cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project * 10cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project * Unless required by applicable law or agreed to in writing, software 11cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project * distributed under the License is distributed on an "AS IS" BASIS, 12cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project * See the License for the specific language governing permissions and 14cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project * limitations under the License. 15cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project */ 16cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 17cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project#include <stdlib.h> 18cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project#include <string.h> 19cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 207987b83553804156aeca61b4c111c2b983c4c551Sergio Giro#include <log/log.h> 21cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 22d2529f28308ba7583f4d8baaa937218d81cbe8bdSergio Giro#include "SharedBuffer.h" 23d2529f28308ba7583f4d8baaa937218d81cbe8bdSergio Giro 24cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project// --------------------------------------------------------------------------- 25cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 26cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Projectnamespace android { 27cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 28cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source ProjectSharedBuffer* SharedBuffer::alloc(size_t size) 29cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project{ 307987b83553804156aeca61b4c111c2b983c4c551Sergio Giro // Don't overflow if the combined size of the buffer / header is larger than 317987b83553804156aeca61b4c111c2b983c4c551Sergio Giro // size_max. 327987b83553804156aeca61b4c111c2b983c4c551Sergio Giro LOG_ALWAYS_FATAL_IF((size >= (SIZE_MAX - sizeof(SharedBuffer))), 337987b83553804156aeca61b4c111c2b983c4c551Sergio Giro "Invalid buffer size %zu", size); 347987b83553804156aeca61b4c111c2b983c4c551Sergio Giro 35cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project SharedBuffer* sb = static_cast<SharedBuffer *>(malloc(sizeof(SharedBuffer) + size)); 36cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (sb) { 3754828dc739e361a795000e8de79d954db3dcbef8Hans Boehm // Should be std::atomic_init(&sb->mRefs, 1); 3854828dc739e361a795000e8de79d954db3dcbef8Hans Boehm // But that generates a warning with some compilers. 3954828dc739e361a795000e8de79d954db3dcbef8Hans Boehm // The following is OK on Android-supported platforms. 4054828dc739e361a795000e8de79d954db3dcbef8Hans Boehm sb->mRefs.store(1, std::memory_order_relaxed); 41cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project sb->mSize = size; 42cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 43cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return sb; 44cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 45cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 46cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 4754828dc739e361a795000e8de79d954db3dcbef8Hans Boehmvoid SharedBuffer::dealloc(const SharedBuffer* released) 48cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project{ 49cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project free(const_cast<SharedBuffer*>(released)); 50cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 51cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 52cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source ProjectSharedBuffer* SharedBuffer::edit() const 53cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project{ 54cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (onlyOwner()) { 55cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return const_cast<SharedBuffer*>(this); 56cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 57cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project SharedBuffer* sb = alloc(mSize); 58cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (sb) { 59cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project memcpy(sb->data(), data(), size()); 60cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project release(); 61cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 627987b83553804156aeca61b4c111c2b983c4c551Sergio Giro return sb; 63cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 64cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 65cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source ProjectSharedBuffer* SharedBuffer::editResize(size_t newSize) const 66cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project{ 67cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (onlyOwner()) { 68cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project SharedBuffer* buf = const_cast<SharedBuffer*>(this); 69cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (buf->mSize == newSize) return buf; 707987b83553804156aeca61b4c111c2b983c4c551Sergio Giro // Don't overflow if the combined size of the new buffer / header is larger than 717987b83553804156aeca61b4c111c2b983c4c551Sergio Giro // size_max. 727987b83553804156aeca61b4c111c2b983c4c551Sergio Giro LOG_ALWAYS_FATAL_IF((newSize >= (SIZE_MAX - sizeof(SharedBuffer))), 737987b83553804156aeca61b4c111c2b983c4c551Sergio Giro "Invalid buffer size %zu", newSize); 747987b83553804156aeca61b4c111c2b983c4c551Sergio Giro 75cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project buf = (SharedBuffer*)realloc(buf, sizeof(SharedBuffer) + newSize); 76cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (buf != NULL) { 77cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project buf->mSize = newSize; 78cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return buf; 79cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 80cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 81cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project SharedBuffer* sb = alloc(newSize); 82cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (sb) { 83cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project const size_t mySize = mSize; 84cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project memcpy(sb->data(), data(), newSize < mySize ? newSize : mySize); 85cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project release(); 86cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 87cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return sb; 88cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 89cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 90cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source ProjectSharedBuffer* SharedBuffer::attemptEdit() const 91cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project{ 92cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (onlyOwner()) { 93cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return const_cast<SharedBuffer*>(this); 94cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 95cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return 0; 96cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 97cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 98cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source ProjectSharedBuffer* SharedBuffer::reset(size_t new_size) const 99cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project{ 100cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project // cheap-o-reset. 101cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project SharedBuffer* sb = alloc(new_size); 102cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (sb) { 103cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project release(); 104cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 105cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return sb; 106cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 107cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 108cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Projectvoid SharedBuffer::acquire() const { 10954828dc739e361a795000e8de79d954db3dcbef8Hans Boehm mRefs.fetch_add(1, std::memory_order_relaxed); 110cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 111cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 112cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Projectint32_t SharedBuffer::release(uint32_t flags) const 113cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project{ 114cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project int32_t prev = 1; 11554828dc739e361a795000e8de79d954db3dcbef8Hans Boehm if (onlyOwner() || ((prev = mRefs.fetch_sub(1, std::memory_order_release) == 1) 11654828dc739e361a795000e8de79d954db3dcbef8Hans Boehm && (atomic_thread_fence(std::memory_order_acquire), true))) { 11754828dc739e361a795000e8de79d954db3dcbef8Hans Boehm mRefs.store(0, std::memory_order_relaxed); 118cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if ((flags & eKeepStorage) == 0) { 119cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project free(const_cast<SharedBuffer*>(this)); 120cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 121cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 122cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return prev; 123cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 124cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 125cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 126cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project}; // namespace android 127