107 lines
2.2 KiB
C++
107 lines
2.2 KiB
C++
/*
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* SharedBuffer.cpp
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* Android
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*
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* Copyright 2005 The Android Open Source Project
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*
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <cutils/atomic.h>
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#include "tinyutils/SharedBuffer.h"
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// ---------------------------------------------------------------------------
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namespace android {
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SharedBuffer* SharedBuffer::alloc(size_t size)
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{
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SharedBuffer* sb = static_cast<SharedBuffer *>(malloc(sizeof(SharedBuffer) + size));
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if (sb) {
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sb->mRefs = 1;
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sb->mSize = size;
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}
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return sb;
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}
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ssize_t SharedBuffer::dealloc(const SharedBuffer* released)
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{
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if (released->mRefs != 0) return -1; // XXX: invalid operation
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free(const_cast<SharedBuffer*>(released));
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return 0;
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}
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SharedBuffer* SharedBuffer::edit() const
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{
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if (onlyOwner()) {
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return const_cast<SharedBuffer*>(this);
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}
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SharedBuffer* sb = alloc(mSize);
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if (sb) {
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memcpy(sb->data(), data(), size());
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release();
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}
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return sb;
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}
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SharedBuffer* SharedBuffer::editResize(size_t newSize) const
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{
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if (onlyOwner()) {
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SharedBuffer* buf = const_cast<SharedBuffer*>(this);
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if (buf->mSize == newSize) return buf;
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buf = (SharedBuffer*)realloc(buf, sizeof(SharedBuffer) + newSize);
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if (buf != NULL) {
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buf->mSize = newSize;
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return buf;
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}
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}
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SharedBuffer* sb = alloc(newSize);
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if (sb) {
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const size_t mySize = mSize;
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memcpy(sb->data(), data(), newSize < mySize ? newSize : mySize);
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release();
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}
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return sb;
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}
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SharedBuffer* SharedBuffer::attemptEdit() const
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{
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if (onlyOwner()) {
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return const_cast<SharedBuffer*>(this);
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}
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return 0;
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}
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SharedBuffer* SharedBuffer::reset(size_t new_size) const
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{
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// cheap-o-reset.
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SharedBuffer* sb = alloc(new_size);
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if (sb) {
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release();
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}
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return sb;
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}
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void SharedBuffer::acquire() const {
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android_atomic_inc(&mRefs);
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}
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int32_t SharedBuffer::release(uint32_t flags) const
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{
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int32_t prev = 1;
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if (onlyOwner() || ((prev = android_atomic_dec(&mRefs)) == 1)) {
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mRefs = 0;
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if ((flags & eKeepStorage) == 0) {
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free(const_cast<SharedBuffer*>(this));
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}
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}
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return prev;
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}
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}; // namespace android
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