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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
// Based on eos' BitStream implementation
#include "common/bitstream.h"
#include "common/memstream.h"
#include "common/stream.h"
#include "common/textconsole.h"
#include "common/util.h"
namespace Common {
BitStream::BitStream() {
}
BitStream::~BitStream() {
}
void BitStream::skip(uint32 n) {
while (n-- > 0)
getBit();
}
BitStreamBE::BitStreamBE(SeekableReadStream &stream, uint32 bitCount) : _value(0), _inValue(0) {
if ((bitCount % 8) != 0)
error("Big-endian bit stream size has to be divisible by 8");
// Read the number of bytes of the stream
uint32 byteSize = bitCount / 8;
byte *data = (byte *)malloc(byteSize);
if (stream.read(data, byteSize) != byteSize) {
free(data);
error("Bad BitStreamBE size");
}
_stream = new MemoryReadStream(data, byteSize, DisposeAfterUse::YES);
}
BitStreamBE::BitStreamBE(const byte *data, uint32 bitCount) : _value(0), _inValue(0) {
if ((bitCount % 8) != 0)
error("Big-endian bit stream size has to be divisible by 8");
// Copy the number of bytes from the data array
uint32 byteSize = bitCount / 8;
byte *dataN = (byte *)malloc(byteSize);
memcpy(dataN, data, byteSize);
_stream = new MemoryReadStream(dataN, byteSize, DisposeAfterUse::YES);
}
BitStreamBE::~BitStreamBE() {
delete _stream;
}
uint32 BitStreamBE::getBit() {
if (_inValue == 0) {
// Need to get new byte
if (_stream->eos())
error("End of bit stream reached");
_value = _stream->readByte();
}
// Get the current bit
int b = ((_value & 0x80) == 0) ? 0 : 1;
// Shift to the next bit
_value <<= 1;
// Increase the position within the current byte
_inValue = (_inValue + 1) % 8;
return b;
}
uint32 BitStreamBE::getBits(uint32 n) {
if (n > 32)
error("Too many bits requested to be read");
// Read the number of bits
uint32 v = 0;
while (n-- > 0)
v = (v << 1) | getBit();
return v;
}
void BitStreamBE::addBit(uint32 &x, uint32 n) {
x = (x << 1) | getBit();
}
uint32 BitStreamBE::pos() const {
if (_stream->pos() == 0)
return 0;
uint32 p = (_inValue == 0) ? _stream->pos() : (_stream->pos() - 1);
return p * 8 + _inValue;
}
uint32 BitStreamBE::size() const {
return _stream->size() * 8;
}
BitStream32LE::BitStream32LE(SeekableReadStream &stream, uint32 bitCount) : _value(0), _inValue(0) {
if ((bitCount % 32) != 0)
error("32bit little-endian bit stream size has to be divisible by 32");
// Read the number of bytes of the stream
uint32 byteSize = bitCount / 8;
byte *data = (byte *)malloc(byteSize);
if (stream.read(data, byteSize) != byteSize) {
free(data);
error("Bad BitStream32LE size");
}
_stream = new MemoryReadStream(data, byteSize, DisposeAfterUse::YES);
}
BitStream32LE::BitStream32LE(const byte *data, uint32 bitCount) : _value(0), _inValue(0) {
if ((bitCount % 32) != 0)
error("32bit little-endian bit stream size has to be divisible by 32");
// Copy the number of bytes from the data array
uint32 byteSize = bitCount / 8;
byte *dataN = (byte *)malloc(byteSize);
memcpy(dataN, data, byteSize);
_stream = new MemoryReadStream(dataN, byteSize, DisposeAfterUse::YES);
}
BitStream32LE::~BitStream32LE() {
delete _stream;
}
uint32 BitStream32LE::getBit() {
if (_inValue == 0) {
// Need to get new 32bit value
if (_stream->eos())
error("End of bit stream reached");
_value = _stream->readUint32LE();
}
// Get the current bit
int b = ((_value & 1) == 0) ? 0 : 1;
// Shift to the next bit
_value >>= 1;
// Increase the position within the current byte
_inValue = (_inValue + 1) % 32;
return b;
}
uint32 BitStream32LE::getBits(uint32 n) {
if (n > 32)
error("Too many bits requested to be read");
// Read the number of bits
uint32 v = 0;
for (uint32 i = 0; i < n; i++)
v = (v >> 1) | (((uint32) getBit()) << 31);
v >>= (32 - n);
return v;
}
void BitStream32LE::addBit(uint32 &x, uint32 n) {
x = (x & ~(1 << n)) | (getBit() << n);
}
uint32 BitStream32LE::pos() const {
if (_stream->pos() == 0)
return 0;
uint32 p = ((_inValue == 0) ? _stream->pos() : (_stream->pos() - 1)) & 0xFFFFFFFC;
return p * 8 + _inValue;
}
uint32 BitStream32LE::size() const {
return _stream->size() * 8;
}
} // End of namespace Common
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