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/*
* Copyright (C) Matthieu Suiche 2008
*
* 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.
*
* 3. Neither the name of the author nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 "lzxpress.h"
#define __BUF_POS_CONST(buf,ofs)(((const guint8 *)buf)+(ofs))
#define __PULL_BYTE(buf,ofs) \
((guint8)((*__BUF_POS_CONST(buf,ofs)) & 0xFF))
#ifndef PULL_LE_UINT16
#define PULL_LE_UINT16(buf,ofs) ((guint16)( \
((guint16)(((guint16)(__PULL_BYTE(buf,(ofs)+0))) << 0)) | \
((guint16)(((guint16)(__PULL_BYTE(buf,(ofs)+1))) << 8)) \
))
#endif
#ifndef PULL_LE_UINT32
#define PULL_LE_UINT32(buf,ofs) ((guint32)( \
((guint32)(((guint32)(__PULL_BYTE(buf,(ofs)+0))) << 0)) | \
((guint32)(((guint32)(__PULL_BYTE(buf,(ofs)+1))) << 8)) | \
((guint32)(((guint32)(__PULL_BYTE(buf,(ofs)+2))) << 16)) | \
((guint32)(((guint32)(__PULL_BYTE(buf,(ofs)+3))) << 24)) \
))
#endif
gssize lzxpress_decompress(const guint8 *input,
guint32 input_size,
guint8 *output,
guint32 max_output_size)
{
guint32 output_index, input_index;
guint32 indicator, indicator_bit;
guint32 length;
guint32 offset;
guint32 nibble_index;
output_index = 0;
input_index = 0;
indicator = 0;
indicator_bit = 0;
nibble_index = 0;
do {
if (indicator_bit == 0) {
indicator = PULL_LE_UINT32(input, input_index);
input_index += (guint32)sizeof(guint32);
indicator_bit = 32;
}
indicator_bit--;
/*
* check whether the bit specified by indicator_bit is set or not
* set in indicator. For example, if indicator_bit has value 4
* check whether the 4th bit of the value in indicator is set
*/
if (((indicator >> indicator_bit) & 1) == 0) {
output[output_index] = input[input_index];
input_index += (guint32)sizeof(guint8);
output_index += (guint32)sizeof(guint8);
} else {
length = PULL_LE_UINT16(input, input_index);
input_index += (guint32)sizeof(guint16);
offset = length / 8;
length = length % 8;
if (length == 7) {
if (nibble_index == 0) {
nibble_index = input_index;
length = input[input_index] % 16;
input_index += (guint32)sizeof(guint8);
} else {
length = input[nibble_index] / 16;
nibble_index = 0;
}
if (length == 15) {
length = input[input_index];
input_index += (guint32)sizeof(guint8);
if (length == 255) {
length = PULL_LE_UINT16(input, input_index);
input_index += (guint32)sizeof(guint16);
length -= (15 + 7);
}
length += 15;
}
length += 7;
}
length += 3;
do {
if ((output_index >= max_output_size) || ((offset + 1) > output_index)) break;
output[output_index] = output[output_index - offset - 1];
output_index += (guint32)sizeof(guint8);
length -= (guint32)sizeof(guint8);
} while (length != 0);
}
} while ((output_index < max_output_size) && (input_index < (input_size)));
return output_index;
}
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