зеркало из https://github.com/mozilla/gecko-dev.git
89 строки
2.5 KiB
C++
89 строки
2.5 KiB
C++
/* vim:set ts=2 sw=2 sts=2 et cindent: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#if !defined(BufferMediaResource_h_)
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#define BufferMediaResource_h_
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#include "MediaResource.h"
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#include "nsISeekableStream.h"
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#include <algorithm>
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namespace mozilla {
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// A simple MediaResource based on an in memory buffer. This class accepts
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// the address and the length of the buffer, and simulates a read/seek API
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// on top of it. The Read implementation involves copying memory, which is
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// unfortunate, but the MediaResource interface mandates that.
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class BufferMediaResource : public MediaResource
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{
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public:
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BufferMediaResource(const uint8_t* aBuffer, uint32_t aLength)
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: mBuffer(aBuffer)
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, mLength(aLength)
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, mOffset(0)
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{
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}
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protected:
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virtual ~BufferMediaResource()
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{
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}
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private:
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// These methods are called off the main thread.
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nsresult ReadAt(int64_t aOffset, char* aBuffer,
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uint32_t aCount, uint32_t* aBytes) override
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{
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if (aOffset < 0 || aOffset > mLength) {
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return NS_ERROR_FAILURE;
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}
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*aBytes = std::min(mLength - static_cast<uint32_t>(aOffset), aCount);
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memcpy(aBuffer, mBuffer + aOffset, *aBytes);
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mOffset = aOffset + *aBytes;
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return NS_OK;
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}
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// Memory-based and no locks, caching discouraged.
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bool ShouldCacheReads() override { return false; }
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int64_t Tell() override { return mOffset; }
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void Pin() override {}
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void Unpin() override {}
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int64_t GetLength() override { return mLength; }
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int64_t GetNextCachedData(int64_t aOffset) override { return aOffset; }
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int64_t GetCachedDataEnd(int64_t aOffset) override
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{
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return std::max(aOffset, int64_t(mLength));
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}
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bool IsDataCachedToEndOfResource(int64_t aOffset) override { return true; }
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nsresult ReadFromCache(char* aBuffer,
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int64_t aOffset,
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uint32_t aCount) override
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{
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if (aOffset < 0) {
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return NS_ERROR_FAILURE;
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}
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uint32_t bytes = std::min(mLength - static_cast<uint32_t>(aOffset), aCount);
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memcpy(aBuffer, mBuffer + aOffset, bytes);
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return NS_OK;
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}
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nsresult GetCachedRanges(MediaByteRangeSet& aRanges) override
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{
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aRanges += MediaByteRange(0, int64_t(mLength));
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return NS_OK;
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}
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private:
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const uint8_t * mBuffer;
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uint32_t mLength;
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uint32_t mOffset;
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};
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} // namespace mozilla
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#endif
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