79 lines
2.4 KiB
C++
79 lines
2.4 KiB
C++
// Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
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// source code may only be used and distributed under the Widevine License
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// Agreement.
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#ifndef WVCDM_UTIL_BUFFER_READER_H_
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#define WVCDM_UTIL_BUFFER_READER_H_
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#include <inttypes.h>
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#include <string>
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#include <vector>
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#include "wv_class_utils.h"
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namespace wvutil {
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// Annotate a function indicating the caller must examine the return value.
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// Use like:
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// int foo() WARN_UNUSED_RESULT;
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// To explicitly ignore a result, see |ignore_result()| in <base/basictypes.h>.
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#if defined(COMPILER_GCC)
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# define WARN_UNUSED_RESULT __attribute__((warn_unused_result))
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#else
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# define WARN_UNUSED_RESULT
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#endif
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class BufferReader {
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public:
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BufferReader() = delete;
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WVCDM_DISALLOW_COPY_AND_MOVE(BufferReader);
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BufferReader(const uint8_t* buf, size_t size)
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: buf_(buf), size_(buf != nullptr ? size : 0) {}
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// == Accessors ==
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constexpr const uint8_t* data() const { return buf_; }
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constexpr size_t size() const { return size_; }
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constexpr size_t pos() const { return pos_; }
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constexpr size_t BytesRemaining() const {
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return size_ >= pos_ ? size_ - pos_ : 0;
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}
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constexpr bool HasBytes(size_t count) const {
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return count <= BytesRemaining();
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}
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constexpr bool IsEof() const { return pos_ >= size_; }
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// Read a value from the stream, performing endian correction,
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// and advance the stream pointer.
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bool Read1(uint8_t* v) WARN_UNUSED_RESULT;
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bool Read2(uint16_t* v) WARN_UNUSED_RESULT;
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bool Read2s(int16_t* v) WARN_UNUSED_RESULT;
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bool Read4(uint32_t* v) WARN_UNUSED_RESULT;
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bool Read4s(int32_t* v) WARN_UNUSED_RESULT;
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bool Read8(uint64_t* v) WARN_UNUSED_RESULT;
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bool Read8s(int64_t* v) WARN_UNUSED_RESULT;
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bool ReadString(std::string* str, size_t count) WARN_UNUSED_RESULT;
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bool ReadVec(std::vector<uint8_t>* t, size_t count) WARN_UNUSED_RESULT;
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// These variants read a 4-byte integer of the corresponding signedness and
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// store it in the 8-byte return type.
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bool Read4Into8(uint64_t* v) WARN_UNUSED_RESULT;
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bool Read4sInto8s(int64_t* v) WARN_UNUSED_RESULT;
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// Advance the stream by this many bytes.
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bool SkipBytes(size_t count) WARN_UNUSED_RESULT;
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private:
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const uint8_t* buf_ = nullptr;
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size_t size_ = 0;
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size_t pos_ = 0;
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template <typename T>
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bool Read(T* t) WARN_UNUSED_RESULT;
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}; // class BufferReader
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} // namespace wvutil
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#endif // WVCDM_UTIL_BUFFER_READER_H_
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