openjpeg/libopenjpeg/raw.c

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2003-11-27 11:10:17 +01:00
/*
* Copyright (c) 2002-2003, Antonin Descampe
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "raw.h"
unsigned char raw_c;
unsigned int raw_ct, raw_lenmax, raw_len;
unsigned char *raw_bp;
unsigned char *raw_start;
unsigned char *raw_end;
/* <summary> */
/* Return the number of bytes already encoded. */
/* </summary> */
int raw_numbytes()
{
return raw_bp - raw_start;
}
/* <summary> */
/* Initialize raw-encoder. */
/* </summary> */
/* <param name="bp">Output buffer.</param> */
void raw_init_enc(unsigned char *bp)
{
raw_bp = bp - 1;
raw_c = 0;
raw_ct = 7;
raw_start = bp;
}
/* <summary> */
/* Encode a symbol using the RAW-coder. */
/* </summary> */
/* <param name="d"> The symbol to be encoded (0 or 1).</param> */
void raw_encode(int d)
{
/* raw_c+=d; */
raw_ct--;
raw_c += (d << raw_ct);
if (raw_ct == 0) {
raw_bp++;
*raw_bp = raw_c;
raw_ct = 7;
if (raw_c == 0xff) {
raw_ct = 6;
}
raw_c = 0;
}
/*else
{
raw_ct--;
raw_c<<=1;
} */
}
/* <summary> */
/* Flush encoded data. */
/* </summary> */
void raw_flush()
{
char first = 1;
int prev = 1;
while (raw_ct != 7) {
raw_encode(first ? 0 : !(prev));
prev = first ? 0 : !(prev);
first = 0;
}
}
/* <summary> */
/* Initialize raw-decoder. */
/* </summary> */
void raw_init_dec(unsigned char *bp, int len)
{
raw_start = bp;
raw_lenmax = len;
raw_len = 0;
raw_c = 0;
raw_ct = 0;
}
/* <summary> */
/* Decode a symbol using raw-decoder. Cfr p.506 TAUBMAN */
/* </summary> */
int raw_decode()
{
int d;
if (raw_ct == 0) {
raw_ct = 8;
if (raw_len == raw_lenmax)
raw_c = 0xff;
else {
if (raw_c == 0xff)
raw_ct = 7;
raw_c = *(raw_start + raw_len);
raw_len++;
}
}
raw_ct--;
d = (raw_c >> raw_ct) & 0x01;
return d;
}