SharedBuffer.cpp revision 7987b83553804156aeca61b4c111c2b983c4c551
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#include <utils/SharedBuffer.h> 22cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project#include <utils/Atomic.h> 23cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 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) { 37cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project sb->mRefs = 1; 38cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project sb->mSize = size; 39cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 40cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return sb; 41cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 42cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 43cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 44cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Projectssize_t SharedBuffer::dealloc(const SharedBuffer* released) 45cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project{ 46cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (released->mRefs != 0) return -1; // XXX: invalid operation 47cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project free(const_cast<SharedBuffer*>(released)); 48cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return 0; 49cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 50cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 51cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source ProjectSharedBuffer* SharedBuffer::edit() const 52cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project{ 53cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (onlyOwner()) { 54cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return const_cast<SharedBuffer*>(this); 55cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 56cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project SharedBuffer* sb = alloc(mSize); 57cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (sb) { 58cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project memcpy(sb->data(), data(), size()); 59cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project release(); 60cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 617987b83553804156aeca61b4c111c2b983c4c551Sergio Giro return sb; 62cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 63cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 64cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source ProjectSharedBuffer* SharedBuffer::editResize(size_t newSize) const 65cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project{ 66cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (onlyOwner()) { 67cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project SharedBuffer* buf = const_cast<SharedBuffer*>(this); 68cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (buf->mSize == newSize) return buf; 697987b83553804156aeca61b4c111c2b983c4c551Sergio Giro // Don't overflow if the combined size of the new buffer / header is larger than 707987b83553804156aeca61b4c111c2b983c4c551Sergio Giro // size_max. 717987b83553804156aeca61b4c111c2b983c4c551Sergio Giro LOG_ALWAYS_FATAL_IF((newSize >= (SIZE_MAX - sizeof(SharedBuffer))), 727987b83553804156aeca61b4c111c2b983c4c551Sergio Giro "Invalid buffer size %zu", newSize); 737987b83553804156aeca61b4c111c2b983c4c551Sergio Giro 74cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project buf = (SharedBuffer*)realloc(buf, sizeof(SharedBuffer) + newSize); 75cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (buf != NULL) { 76cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project buf->mSize = newSize; 77cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return buf; 78cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 79cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 80cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project SharedBuffer* sb = alloc(newSize); 81cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (sb) { 82cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project const size_t mySize = mSize; 83cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project memcpy(sb->data(), data(), newSize < mySize ? newSize : mySize); 84cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project release(); 85cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 86cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return sb; 87cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 88cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 89cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source ProjectSharedBuffer* SharedBuffer::attemptEdit() const 90cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project{ 91cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (onlyOwner()) { 92cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return const_cast<SharedBuffer*>(this); 93cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 94cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return 0; 95cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 96cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 97cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source ProjectSharedBuffer* SharedBuffer::reset(size_t new_size) const 98cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project{ 99cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project // cheap-o-reset. 100cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project SharedBuffer* sb = alloc(new_size); 101cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (sb) { 102cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project release(); 103cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 104cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return sb; 105cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 106cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 107cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Projectvoid SharedBuffer::acquire() const { 108cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project android_atomic_inc(&mRefs); 109cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 110cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 111cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Projectint32_t SharedBuffer::release(uint32_t flags) const 112cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project{ 113cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project int32_t prev = 1; 114cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if (onlyOwner() || ((prev = android_atomic_dec(&mRefs)) == 1)) { 115cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project mRefs = 0; 116cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project if ((flags & eKeepStorage) == 0) { 117cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project free(const_cast<SharedBuffer*>(this)); 118cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 119cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project } 120cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project return prev; 121cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project} 122cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 123cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project 124cbb1011c95e0c25c29e40e203a6a31bccd029da3The Android Open Source Project}; // namespace android 125