289acf3333
The build system used by rbutil is not very robust: all the files are eventually compiled to the same directory so we cannot have two files with the same name (system.c would conflicts with system.cpp) so rename one file to avoid this. Also change all include directives to local ones because we don't have to expose the entire mspack source to inclusion. Change-Id: I3fe0638d69fdc30566eb9425abfe33c807678b28 Reviewed-on: http://gerrit.rockbox.org/417 Reviewed-by: Dominik Riebeling <Dominik.Riebeling@gmail.com>
93 lines
2.6 KiB
C
93 lines
2.6 KiB
C
/* This file is part of libmspack.
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* (C) 2003-2010 Stuart Caie.
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*
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* LZSS is a derivative of LZ77 and was created by James Storer and
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* Thomas Szymanski in 1982. Haruhiko Okumura wrote a very popular C
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* implementation.
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*
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* libmspack is free software; you can redistribute it and/or modify it under
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* the terms of the GNU Lesser General Public License (LGPL) version 2.1
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*
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* For further details, see the file COPYING.LIB distributed with libmspack
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*/
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#include "system-mspack.h"
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#include "lzss.h"
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#define ENSURE_BYTES do { \
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if (i_ptr >= i_end) { \
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read = system->read(input, &inbuf[0], \
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input_buffer_size); \
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if (read <= 0) { \
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system->free(window); \
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return (read < 0) ? MSPACK_ERR_READ \
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: MSPACK_ERR_OK; \
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} \
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i_ptr = &inbuf[0]; i_end = &inbuf[read]; \
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} \
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} while (0)
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#define WRITE_BYTE do { \
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if (system->write(output, &window[pos], 1) != 1) { \
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system->free(window); \
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return MSPACK_ERR_WRITE; \
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} \
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} while (0)
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int lzss_decompress(struct mspack_system *system,
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struct mspack_file *input,
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struct mspack_file *output,
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int input_buffer_size,
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int mode)
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{
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unsigned char *window, *inbuf, *i_ptr, *i_end;
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unsigned int pos, i, c, invert, mpos, len;
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int read;
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/* check parameters */
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if (!system || input_buffer_size < 1 || (mode != LZSS_MODE_EXPAND &&
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mode != LZSS_MODE_MSHELP && mode != LZSS_MODE_QBASIC))
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{
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return MSPACK_ERR_ARGS;
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}
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/* allocate memory */
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window = (unsigned char *) system->alloc(system, LZSS_WINDOW_SIZE + input_buffer_size);
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if (!window) return MSPACK_ERR_NOMEMORY;
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/* initialise decompression */
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inbuf = &window[LZSS_WINDOW_SIZE];
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memset(window, LZSS_WINDOW_FILL, (size_t) LZSS_WINDOW_SIZE);
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pos = LZSS_WINDOW_SIZE - ((mode == LZSS_MODE_QBASIC) ? 18 : 16);
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invert = (mode == LZSS_MODE_MSHELP) ? ~0 : 0;
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i_ptr = i_end = &inbuf[0];
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/* loop forever; exit condition is in ENSURE_BYTES macro */
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for (;;) {
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ENSURE_BYTES; c = *i_ptr++ ^ invert;
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for (i = 0x01; i & 0xFF; i <<= 1) {
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if (c & i) {
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/* literal */
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ENSURE_BYTES; window[pos] = *i_ptr++;
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WRITE_BYTE;
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pos++; pos &= LZSS_WINDOW_SIZE - 1;
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}
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else {
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/* match */
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ENSURE_BYTES; mpos = *i_ptr++;
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ENSURE_BYTES; mpos |= (*i_ptr & 0xF0) << 4;
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len = (*i_ptr++ & 0x0F) + 3;
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while (len--) {
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window[pos] = window[mpos];
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WRITE_BYTE;
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pos++; pos &= LZSS_WINDOW_SIZE - 1;
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mpos++; mpos &= LZSS_WINDOW_SIZE - 1;
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}
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}
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}
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}
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/* not reached */
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system->free(window);
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return MSPACK_ERR_OK;
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}
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