79 lines
2.6 KiB
C++
79 lines
2.6 KiB
C++
|
/*
|
||
|
|
* Copyright (C) 2010 The Android Open Source Project
|
||
|
|
*
|
||
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
|
* you may not use this file except in compliance with the License.
|
||
|
|
* You may obtain a copy of the License at
|
||
|
|
*
|
||
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
*
|
||
|
|
* Unless required by applicable law or agreed to in writing, software
|
||
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
* See the License for the specific language governing permissions and
|
||
|
|
* limitations under the License.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef AML_MP_BIT_READER_H_
|
||
|
|
|
||
|
|
#define AML_MP_BIT_READER_H_
|
||
|
|
|
||
|
|
//#include <media/stagefright/foundation/ABase.h>
|
||
|
|
|
||
|
|
#include <sys/types.h>
|
||
|
|
#include <stdint.h>
|
||
|
|
|
||
|
|
namespace aml_mp {
|
||
|
|
|
||
|
|
class AmlMpBitReader {
|
||
|
|
public:
|
||
|
|
AmlMpBitReader(const uint8_t *data, size_t size);
|
||
|
|
virtual ~AmlMpBitReader();
|
||
|
|
|
||
|
|
// Tries to get |n| bits. If not successful, returns |fallback|. Otherwise, returns result.
|
||
|
|
// Reading 0 bits will always succeed and return 0.
|
||
|
|
uint32_t getBitsWithFallback(size_t n, uint32_t fallback);
|
||
|
|
|
||
|
|
// Tries to get |n| bits. If not successful, returns false. Otherwise, stores result in |out|
|
||
|
|
// and returns true. Use !overRead() to determine if this call was successful. Reading 0 bits
|
||
|
|
// will always succeed and write 0 in |out|.
|
||
|
|
bool getBitsGraceful(size_t n, uint32_t *out);
|
||
|
|
|
||
|
|
// Gets |n| bits and returns result. ABORTS if unsuccessful. Reading 0 bits will always
|
||
|
|
// succeed.
|
||
|
|
uint32_t getBits(size_t n);
|
||
|
|
|
||
|
|
// Tries to skip |n| bits. Returns true iff successful. Skipping 0 bits will always succeed.
|
||
|
|
bool skipBits(size_t n);
|
||
|
|
|
||
|
|
// "Puts" |n| bits with the value |x| back virtually into the bit stream. The put-back bits
|
||
|
|
// are not actually written into the data, but are tracked in a separate buffer that can
|
||
|
|
// store at most 32 bits. This is a no-op if the stream has already been over-read.
|
||
|
|
void putBits(uint32_t x, size_t n);
|
||
|
|
|
||
|
|
size_t numBitsLeft() const;
|
||
|
|
|
||
|
|
const uint8_t *data() const;
|
||
|
|
|
||
|
|
// Returns true iff the stream was over-read (e.g. any getBits operation has been unsuccessful
|
||
|
|
// due to overread (and not trying to read >32 bits).)
|
||
|
|
bool overRead() const { return mOverRead; }
|
||
|
|
|
||
|
|
protected:
|
||
|
|
const uint8_t *mData;
|
||
|
|
size_t mSize;
|
||
|
|
|
||
|
|
uint32_t mReservoir; // left-aligned bits
|
||
|
|
size_t mNumBitsLeft;
|
||
|
|
bool mOverRead;
|
||
|
|
|
||
|
|
virtual bool fillReservoir();
|
||
|
|
|
||
|
|
AmlMpBitReader(const AmlMpBitReader&) = delete;
|
||
|
|
AmlMpBitReader& operator= (const AmlMpBitReader&) = delete;
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace android
|
||
|
|
|
||
|
|
#endif // A_BIT_READER_H_
|