729b6e4f33
Update to the most recent release. Fix name / include clashes, as has been done before. Change-Id: Ia712bb2b5f4b9018b65a46b8bdd04ba42363be8b
247 lines
7.5 KiB
C
247 lines
7.5 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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* SZDD is a format used in the MS-DOS commands COMPRESS.EXE and
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* EXPAND.EXE. The compression method is attributed to Steven Zeck,
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* however it's pretty much identical to LZSS.
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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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/* SZDD decompression implementation */
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#include "system-mspack.h"
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#include "szdd.h"
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/* prototypes */
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static struct msszddd_header *szddd_open(
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struct msszdd_decompressor *base, const char *filename);
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static void szddd_close(
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struct msszdd_decompressor *base, struct msszddd_header *hdr);
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static int szddd_read_headers(
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struct mspack_system *sys, struct mspack_file *fh,
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struct msszddd_header *hdr);
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static int szddd_extract(
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struct msszdd_decompressor *base, struct msszddd_header *hdr,
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const char *filename);
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static int szddd_decompress(
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struct msszdd_decompressor *base, const char *input, const char *output);
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static int szddd_error(
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struct msszdd_decompressor *base);
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/***************************************
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* MSPACK_CREATE_SZDD_DECOMPRESSOR
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***************************************
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* constructor
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*/
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struct msszdd_decompressor *
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mspack_create_szdd_decompressor(struct mspack_system *sys)
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{
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struct msszdd_decompressor_p *self = NULL;
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if (!sys) sys = mspack_default_system;
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if (!mspack_valid_system(sys)) return NULL;
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if ((self = (struct msszdd_decompressor_p *) sys->alloc(sys, sizeof(struct msszdd_decompressor_p)))) {
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self->base.open = &szddd_open;
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self->base.close = &szddd_close;
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self->base.extract = &szddd_extract;
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self->base.decompress = &szddd_decompress;
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self->base.last_error = &szddd_error;
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self->system = sys;
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self->error = MSPACK_ERR_OK;
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}
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return (struct msszdd_decompressor *) self;
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}
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/***************************************
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* MSPACK_DESTROY_SZDD_DECOMPRESSOR
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***************************************
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* destructor
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*/
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void mspack_destroy_szdd_decompressor(struct msszdd_decompressor *base)
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{
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struct msszdd_decompressor_p *self = (struct msszdd_decompressor_p *) base;
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if (self) {
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struct mspack_system *sys = self->system;
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sys->free(self);
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}
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}
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/***************************************
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* SZDDD_OPEN
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***************************************
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* opens an SZDD file without decompressing, reads header
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*/
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static struct msszddd_header *szddd_open(struct msszdd_decompressor *base,
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const char *filename)
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{
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struct msszdd_decompressor_p *self = (struct msszdd_decompressor_p *) base;
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struct msszddd_header *hdr;
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struct mspack_system *sys;
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struct mspack_file *fh;
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if (!self) return NULL;
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sys = self->system;
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fh = sys->open(sys, filename, MSPACK_SYS_OPEN_READ);
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hdr = (struct msszddd_header *) sys->alloc(sys, sizeof(struct msszddd_header_p));
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if (fh && hdr) {
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((struct msszddd_header_p *) hdr)->fh = fh;
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self->error = szddd_read_headers(sys, fh, hdr);
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}
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else {
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if (!fh) self->error = MSPACK_ERR_OPEN;
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if (!hdr) self->error = MSPACK_ERR_NOMEMORY;
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}
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if (self->error) {
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if (fh) sys->close(fh);
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sys->free(hdr);
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hdr = NULL;
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}
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return hdr;
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}
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/***************************************
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* SZDDD_CLOSE
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***************************************
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* closes an SZDD file
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*/
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static void szddd_close(struct msszdd_decompressor *base,
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struct msszddd_header *hdr)
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{
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struct msszdd_decompressor_p *self = (struct msszdd_decompressor_p *) base;
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struct msszddd_header_p *hdr_p = (struct msszddd_header_p *) hdr;
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if (!self || !self->system) return;
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/* close the file handle associated */
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self->system->close(hdr_p->fh);
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/* free the memory associated */
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self->system->free(hdr);
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self->error = MSPACK_ERR_OK;
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}
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/***************************************
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* SZDDD_READ_HEADERS
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***************************************
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* reads the headers of an SZDD format file
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*/
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static unsigned char szdd_signature_expand[8] = {
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0x53, 0x5A, 0x44, 0x44, 0x88, 0xF0, 0x27, 0x33
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};
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static unsigned char szdd_signature_qbasic[8] = {
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0x53, 0x5A, 0x20, 0x88, 0xF0, 0x27, 0x33, 0xD1
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};
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static int szddd_read_headers(struct mspack_system *sys,
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struct mspack_file *fh,
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struct msszddd_header *hdr)
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{
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unsigned char buf[8];
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/* read and check signature */
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if (sys->read(fh, buf, 8) != 8) return MSPACK_ERR_READ;
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if ((memcmp(buf, szdd_signature_expand, 8) == 0)) {
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/* common SZDD */
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hdr->format = MSSZDD_FMT_NORMAL;
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/* read the rest of the header */
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if (sys->read(fh, buf, 6) != 6) return MSPACK_ERR_READ;
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if (buf[0] != 0x41) return MSPACK_ERR_DATAFORMAT;
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hdr->missing_char = buf[1];
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hdr->length = EndGetI32(&buf[2]);
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}
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else if ((memcmp(buf, szdd_signature_qbasic, 8) == 0)) {
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/* special QBasic SZDD */
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hdr->format = MSSZDD_FMT_QBASIC;
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if (sys->read(fh, buf, 4) != 4) return MSPACK_ERR_READ;
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hdr->missing_char = '\0';
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hdr->length = EndGetI32(buf);
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}
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else {
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return MSPACK_ERR_SIGNATURE;
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}
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return MSPACK_ERR_OK;
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}
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/***************************************
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* SZDDD_EXTRACT
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***************************************
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* decompresses an SZDD file
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*/
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static int szddd_extract(struct msszdd_decompressor *base,
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struct msszddd_header *hdr, const char *filename)
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{
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struct msszdd_decompressor_p *self = (struct msszdd_decompressor_p *) base;
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struct mspack_file *fh, *outfh;
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struct mspack_system *sys;
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off_t data_offset;
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if (!self) return MSPACK_ERR_ARGS;
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if (!hdr) return self->error = MSPACK_ERR_ARGS;
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sys = self->system;
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fh = ((struct msszddd_header_p *) hdr)->fh;
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/* seek to the compressed data */
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data_offset = (hdr->format == MSSZDD_FMT_NORMAL) ? 14 : 12;
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if (sys->seek(fh, data_offset, MSPACK_SYS_SEEK_START)) {
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return self->error = MSPACK_ERR_SEEK;
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}
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/* open file for output */
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if (!(outfh = sys->open(sys, filename, MSPACK_SYS_OPEN_WRITE))) {
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return self->error = MSPACK_ERR_OPEN;
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}
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/* decompress the data */
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self->error = lzss_decompress(sys, fh, outfh, SZDD_INPUT_SIZE,
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hdr->format == MSSZDD_FMT_NORMAL
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? LZSS_MODE_EXPAND
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: LZSS_MODE_QBASIC);
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/* close output file */
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sys->close(outfh);
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return self->error;
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}
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/***************************************
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* SZDDD_DECOMPRESS
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***************************************
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* unpacks directly from input to output
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*/
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static int szddd_decompress(struct msszdd_decompressor *base,
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const char *input, const char *output)
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{
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struct msszdd_decompressor_p *self = (struct msszdd_decompressor_p *) base;
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struct msszddd_header *hdr;
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int error;
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if (!self) return MSPACK_ERR_ARGS;
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if (!(hdr = szddd_open(base, input))) return self->error;
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error = szddd_extract(base, hdr, output);
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szddd_close(base, hdr);
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return self->error = error;
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}
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/***************************************
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* SZDDD_ERROR
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***************************************
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* returns the last error that occurred
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*/
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static int szddd_error(struct msszdd_decompressor *base)
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{
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struct msszdd_decompressor_p *self = (struct msszdd_decompressor_p *) base;
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return (self) ? self->error : MSPACK_ERR_ARGS;
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}
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