Files
Konrad Beckmann 20d7fefaf9 Import mikmod
2021-08-02 02:19:41 +02:00

213 lines
6.3 KiB
C

/* MikMod sound library (c) 2003-2015 Raphael Assenat and others -
* see AUTHORS file for a complete list.
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program 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 Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*/
/* amiga Powerpack PP20 decompression support
*
* Code from Heikki Orsila's amigadepack 0.02
* based on code by Stuart Caie <kyzer@4u.net>
* This software is in the Public Domain
*
* Modified for xmp by Claudio Matsuoka, 08/2007
* - merged mld's checks from the old depack sources. Original credits:
* - corrupt file and data detection
* (thanks to Don Adan and Dirk Stoecker for help and infos)
* - implemeted "efficiency" checks
* - further detection based on code by Georg Hoermann
*
* Modified for xmp by Claudio Matsuoka, 05/2013
* - decryption code removed
*
* Modified for libmikmod by O. Sezer, Apr. 2015, with a few extra bits
* from the libmodplug library by Olivier Lapicque.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#ifndef NO_DEPACKERS
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdio.h>
#ifdef HAVE_MEMORY_H
#include <memory.h>
#endif
#include <string.h>
#include "mikmod_internals.h"
#ifdef SUNOS
extern int fprintf(FILE *, const char *, ...);
#endif
#define PP_READ_BITS(nbits, var) do { \
bit_cnt = (nbits); \
while (bits_left < bit_cnt) { \
if (buf_src <= src) return 0; /* out of source bits */ \
bit_buffer |= (*--buf_src << bits_left); \
bits_left += 8; \
} \
(var) = 0; \
bits_left -= bit_cnt; \
while (bit_cnt--) { \
(var) = ((var) << 1) | (bit_buffer & 1); \
bit_buffer >>= 1; \
} \
} while(0)
#define PP_BYTE_OUT(byte) do { \
if (out <= dest) return 0; /* output overflow */ \
*--out = (byte); \
written++; \
} while (0)
static BOOL ppDecrunch(const UBYTE *src, UBYTE *dest,
const UBYTE *offset_lens,
ULONG src_len, ULONG dest_len,
UBYTE skip_bits)
{
ULONG bit_buffer, x, todo, offbits, offset, written;
const UBYTE *buf_src;
UBYTE *out, *dest_end, bits_left, bit_cnt;
/* set up input and output pointers */
buf_src = src + src_len;
out = dest_end = dest + dest_len;
written = 0;
bit_buffer = 0;
bits_left = 0;
/* skip the first few bits */
PP_READ_BITS(skip_bits, x);
/* while there are input bits left */
while (written < dest_len) {
PP_READ_BITS(1, x);
if (x == 0) {
/* 1bit==0: literal, then match. 1bit==1: just match */
todo = 1; do { PP_READ_BITS(2, x); todo += x; } while (x == 3);
while (todo--) { PP_READ_BITS(8, x); PP_BYTE_OUT(x); }
/* should we end decoding on a literal, break out of the main loop */
if (written == dest_len) break;
}
/* match: read 2 bits for initial offset bitlength / match length */
PP_READ_BITS(2, x);
offbits = offset_lens[x];
todo = x+2;
if (x == 3) {
PP_READ_BITS(1, x);
if (x==0) offbits = 7;
PP_READ_BITS(offbits, offset);
do { PP_READ_BITS(3, x); todo += x; } while (x == 7);
}
else {
PP_READ_BITS(offbits, offset);
}
if ((out + offset) >= dest_end) return 0; /* match overflow */
while (todo--) { x = out[offset]; PP_BYTE_OUT(x); }
}
/* all output bytes written without error */
return 1;
/* return (src == buf_src) ? 1 : 0; */
}
BOOL PP20_Unpack(MREADER* reader, void** out, long* outlen)
{
ULONG srclen, destlen;
UBYTE *destbuf, *srcbuf;
UBYTE tmp[4], skip;
BOOL ret;
/* PP FORMAT:
* 1 longword identifier 'PP20' or 'PX20'
* [1 word checksum (if 'PX20') $ssss]
* 1 longword efficiency $eeeeeeee
* X longwords crunched file $cccccccc,$cccccccc,...
* 1 longword decrunch info 'decrlen' << 8 | '8 bits other info'
*/
_mm_fseek(reader,0,SEEK_END);
srclen = _mm_ftell(reader);
if (srclen < 256) return 0;
/* file length should be a multiple of 4 */
if (srclen & 3) return 0;
_mm_rewind(reader);
if (_mm_read_I_ULONG(reader) != 0x30325050) /* 'PP20' */
return 0;
_mm_fseek(reader,srclen-4,SEEK_SET);
_mm_read_UBYTES(tmp,4,reader);
destlen = tmp[0] << 16;
destlen |= tmp[1] << 8;
destlen |= tmp[2];
skip = tmp[3];
_mm_fseek(reader,4,SEEK_SET);
_mm_read_UBYTES(tmp,4,reader);
/* original pp20 only support efficiency
* from 9 9 9 9 up to 9 10 12 13, afaik,
* but the xfd detection code says this...
*
* move.l 4(a0),d0
* cmp.b #9,d0
* blo.b .Exit
* and.l #$f0f0f0f0,d0
* bne.s .Exit
*/
if ((tmp[0] < 9) || (tmp[0] & 0xf0)) return 0;
if ((tmp[1] < 9) || (tmp[1] & 0xf0)) return 0;
if ((tmp[2] < 9) || (tmp[2] & 0xf0)) return 0;
if ((tmp[3] < 9) || (tmp[3] & 0xf0)) return 0;
if ((destlen < 512) || (destlen > 0x400000) || (destlen > 16*srclen))
return 0;
if ((destbuf = (UBYTE*)MikMod_malloc(destlen)) == NULL)
return 0;
srclen -= 12;
if ((srcbuf = (UBYTE*)MikMod_malloc(srclen)) == NULL) {
MikMod_free(destbuf);
return 0;
}
_mm_read_UBYTES(srcbuf,srclen,reader);
ret = ppDecrunch(srcbuf, destbuf, tmp, srclen, destlen, skip);
MikMod_free(srcbuf);
if (!ret) {
MikMod_free(destbuf);
}
else {
*out = destbuf;
*outlen = destlen;
}
return ret;
}
#endif /* NO_DEPACKERS */