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/*
* $Id: cobs.c,v 1.14 2010/02/05 23:50:22 simakov Exp $
*
* EPSILON - wavelet image compression library.
* Copyright (C) 2006,2007,2010 Alexander Simakov, <xander@entropyware.info>
*
* This file is part of EPSILON
*
* EPSILON 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.
*
* EPSILON 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 EPSILON. If not, see <http://www.gnu.org/licenses/>.
*
* http://epsilon-project.sourceforge.net
*/
#include <common.h>
#include <cobs.h>
#define FINISH_BLOCK(_x) (*code_ptr = (_x), \
code_ptr = output_data++, \
code = 0x01)
int stuff_data(unsigned char *input_data, unsigned char *output_data,
int input_length, int output_length)
{
unsigned char *input_end = input_data + input_length;
unsigned char *output_start = output_data;
unsigned char *code_ptr = output_data++;
unsigned char code = 0x01;
/* Sanity checks */
assert(input_length > 0);
assert(output_length >= input_length + input_length / 254 + 1);
while (input_data < input_end) {
if (*input_data == 0) {
FINISH_BLOCK(code);
} else {
*output_data++ = *input_data;
code++;
if (code == 0xff) {
FINISH_BLOCK(code);
}
}
input_data++;
}
FINISH_BLOCK(code);
return output_data - output_start - 1;
}
int unstuff_data(unsigned char *input_data, unsigned char *output_data,
int input_length, int output_length)
{
unsigned char *input_end = input_data + input_length;
unsigned char *output_end = output_data + output_length;
unsigned char *output_start = output_data;
/* Sanity checks */
assert(input_length > 0);
assert(output_length >= input_length);
while (input_data < input_end) {
int code = *input_data++;
int i;
for (i = 1; (i < code) && (input_data < input_end) && (output_data < output_end); i++) {
*output_data++ = *input_data++;
}
if ((code > 0x00) && (code < 0xff) &&
(input_data < input_end) && (output_data < output_end)) {
*output_data++ = 0;
}
}
return output_data - output_start;
}
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