78 lines
2.1 KiB
C++
78 lines
2.1 KiB
C++
// Copyright (c) 2013 Google Inc. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "media/base/buffer_reader.h"
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#include "base/logging.h"
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namespace media {
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bool BufferReader::Read1(uint8* v) {
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DCHECK(v != NULL);
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if (!HasBytes(1))
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return false;
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*v = buf_[pos_++];
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return true;
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}
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bool BufferReader::Read2(uint16* v) { return Read(v); }
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bool BufferReader::Read2s(int16* v) { return Read(v); }
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bool BufferReader::Read4(uint32* v) { return Read(v); }
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bool BufferReader::Read4s(int32* v) { return Read(v); }
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bool BufferReader::Read8(uint64* v) { return Read(v); }
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bool BufferReader::Read8s(int64* v) { return Read(v); }
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bool BufferReader::ReadNBytesInto8(uint64* v, size_t num_bytes) {
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return ReadNBytes(v, num_bytes);
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}
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bool BufferReader::ReadNBytesInto8s(int64* v, size_t num_bytes) {
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return ReadNBytes(v, num_bytes);
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}
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bool BufferReader::ReadToVector(std::vector<uint8>* vec, size_t count) {
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DCHECK(vec != NULL);
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if (!HasBytes(count))
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return false;
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vec->assign(buf_ + pos_, buf_ + pos_ + count);
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pos_ += count;
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return true;
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}
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bool BufferReader::SkipBytes(size_t num_bytes) {
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if (!HasBytes(num_bytes))
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return false;
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pos_ += num_bytes;
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return true;
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}
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template <typename T>
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bool BufferReader::Read(T* v) {
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return ReadNBytes(v, sizeof(*v));
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}
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template <typename T>
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bool BufferReader::ReadNBytes(T* v, size_t num_bytes) {
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DCHECK(v != NULL);
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DCHECK_LE(num_bytes, sizeof(*v));
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if (!HasBytes(num_bytes))
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return false;
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// Sign extension is required only if
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// |num_bytes| is less than size of T, and
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// T is a signed type.
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const bool sign_extension_required =
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num_bytes < sizeof(*v) && static_cast<T>(-1) < 0;
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// Perform sign extension by casting the byte value to int8, which will be
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// sign extended automatically when it is implicitly converted to T.
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T tmp =
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sign_extension_required ? static_cast<int8>(buf_[pos_++]) : buf_[pos_++];
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for (size_t i = 1; i < num_bytes; ++i) {
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tmp <<= 8;
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tmp |= buf_[pos_++];
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}
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*v = tmp;
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return true;
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}
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} // namespace media
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