OpenV2G/src/codec/BitOutputStream.c
daniel_peintner 69e25e0172 * improves EXI codec footprint
git-svn-id: https://svn.code.sf.net/p/openv2g/code/trunk@15 d9f2db14-54d0-4bde-b00c-16405c910529
2010-10-20 12:22:39 +00:00

95 lines
2.6 KiB
C

/*
* Copyright (C) 2007-2010 Siemens AG
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation, either version 3 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*******************************************************************
*
* @author Daniel.Peintner.EXT@siemens.com
* @version 0.2.2
* @contact Joerg.Heuer@siemens.com
*
********************************************************************/
#include <string.h>
#include "EXITypes.h"
#include "BitOutputStream.h"
#ifndef BIT_OUTPUT_STREAM_C
#define BIT_OUTPUT_STREAM_C
/* NOTE: nbits <= 8 */
int writeBits(bitstream_t* stream, size_t nbits, uint8_t val) {
/* is there enough space in the buffer */
if (nbits <= stream->capacity) {
/* all bits fit into the current buffer */
stream->buffer = (stream->buffer << (nbits)) | (val & (0xff
>> (BITS_IN_BYTE - nbits)));
stream->capacity -= nbits;
/* if the buffer is full write it into the data */
if (stream->capacity == 0) {
if ((*stream->pos) >= stream->size) {
return -1;
}
stream->data[(*stream->pos)++] = 0xFF & stream->buffer;
stream->capacity = BITS_IN_BYTE;
stream->buffer = 0;
}
} else {
/* the buffer is not enough
* fill the buffer */
stream->buffer = (stream->buffer << stream->capacity) | ((val >> (nbits
- stream->capacity)) & (0xff >> (BITS_IN_BYTE
- stream->capacity)));
nbits -= stream->capacity;
if ((*stream->pos) >= stream->size) {
return -1;
}
stream->data[(*stream->pos)++] = 0xFF & stream->buffer;
stream->buffer = 0;
/* write whole bytes */
while (nbits >= BITS_IN_BYTE) {
nbits -= BITS_IN_BYTE;
if ((*stream->pos) >= stream->size) {
return -1;
}
stream->data[(*stream->pos)++] = 0xFF & (val >> (nbits));
}
/* spared bits are kept in the buffer */
stream->buffer = val; /* Note: the high bits will be shifted out during further filling */
stream->capacity = BITS_IN_BYTE - (nbits);
}
return 0;
}
/**
* Flush output
*/
int flush(bitstream_t* stream) {
if (stream->capacity == BITS_IN_BYTE) {
/* nothing to do, no bits in buffer */
return 0;
} else {
return writeBits(stream, stream->capacity, 0);
}
}
#endif