diff options
| -rw-r--r-- | common/bitstream.h | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/common/bitstream.h b/common/bitstream.h index 6b9ab97237..c5226d5124 100644 --- a/common/bitstream.h +++ b/common/bitstream.h @@ -50,7 +50,8 @@ private: uint32 _value; ///< Current value. uint8 _inValue; ///< Position within the current value. - uint32 _size; + uint32 _size; ///< Total bitstream size (in bits) + uint32 _pos; ///< Current bitstream position (in bits) /** Read a data value. */ inline uint32 readData() { @@ -76,7 +77,7 @@ private: /** Read the next data value. */ inline void readValue() { - if ((_size - pos()) < valueBits) + if (_size - _pos < valueBits) error("BitStreamImpl::readValue(): End of bit stream reached"); _value = readData(); @@ -91,7 +92,7 @@ private: public: /** Create a bit stream using this input data stream and optionally delete it on destruction. */ BitStreamImpl(STREAM *stream, DisposeAfterUse::Flag disposeAfterUse = DisposeAfterUse::NO) : - _stream(stream), _disposeAfterUse(disposeAfterUse), _value(0), _inValue(0) { + _stream(stream), _disposeAfterUse(disposeAfterUse), _value(0), _inValue(0), _pos(0) { if ((valueBits != 8) && (valueBits != 16) && (valueBits != 32)) error("BitStreamImpl: Invalid memory layout %d, %d, %d", valueBits, isLE, isMSB2LSB); @@ -101,7 +102,7 @@ public: /** Create a bit stream using this input data stream. */ BitStreamImpl(STREAM &stream) : - _stream(&stream), _disposeAfterUse(DisposeAfterUse::NO), _value(0), _inValue(0) { + _stream(&stream), _disposeAfterUse(DisposeAfterUse::NO), _value(0), _inValue(0), _pos(0) { if ((valueBits != 8) && (valueBits != 16) && (valueBits != 32)) error("BitStreamImpl: Invalid memory layout %d, %d, %d", valueBits, isLE, isMSB2LSB); @@ -135,6 +136,7 @@ public: // Increase the position within the current value _inValue = (_inValue + 1) % valueBits; + _pos++; return b; } @@ -176,11 +178,13 @@ public: uint32 peekBit() { uint32 value = _value; uint8 inValue = _inValue; - uint32 curPos = _stream->pos(); + uint32 curStreamPos = _stream->pos(); + uint32 curPos = _pos; uint32 v = getBit(); - _stream->seek(curPos); + _pos = curPos; + _stream->seek(curStreamPos); _inValue = inValue; _value = value; @@ -195,11 +199,13 @@ public: uint32 peekBits(uint8 n) { uint32 value = _value; uint8 inValue = _inValue; - uint32 curPos = _stream->pos(); + uint32 curStreamPos = _stream->pos(); + uint32 curPos = _pos; uint32 v = getBits(n); - _stream->seek(curPos); + _pos = curPos; + _stream->seek(curStreamPos); _inValue = inValue; _value = value; @@ -233,6 +239,7 @@ public: _value = 0; _inValue = 0; + _pos = 0; } /** Skip the specified amount of bits. */ @@ -249,11 +256,7 @@ public: /** Return the stream position in bits. */ uint32 pos() const { - if (_stream->pos() == 0) - return 0; - - uint32 p = (_inValue == 0) ? _stream->pos() : ((_stream->pos() - 1) & ~((uint32) ((valueBits >> 3) - 1))); - return p * 8 + _inValue; + return _pos; } /** Return the stream size in bits. */ @@ -262,7 +265,7 @@ public: } bool eos() const { - return _stream->eos() || (pos() >= _size); + return _stream->eos() || (_pos >= _size); } }; |