mirror of
https://github.com/tildearrow/furnace.git
synced 2024-11-26 14:33:01 +00:00
244 lines
7.6 KiB
C
244 lines
7.6 KiB
C
/*
|
|
* Schism Tracker - a cross-platform Impulse Tracker clone
|
|
* copyright (c) 2003-2005 Storlek <storlek@rigelseven.com>
|
|
* copyright (c) 2005-2008 Mrs. Brisby <mrs.brisby@nimh.org>
|
|
* copyright (c) 2009 Storlek & Mrs. Brisby
|
|
* copyright (c) 2010-2012 Storlek
|
|
* URL: http://schismtracker.org/
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU 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 General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*/
|
|
|
|
// slightly modified for Furnace by tildearrow
|
|
|
|
#include "compression.h"
|
|
|
|
#define MIN(a,b) (((a)<(b))?(a):(b))
|
|
#define MAX(a,b) (((a)>(b))?(a):(b))
|
|
#define CLAMP(x,xMin,xMax) (MIN(MAX((x),(xMin)),(xMax)))
|
|
|
|
// ------------------------------------------------------------------------------------------------------------
|
|
// IT decompression code from itsex.c (Cubic Player) and load_it.cpp (Modplug)
|
|
// (I suppose this could be considered a merge between the two.)
|
|
|
|
static uint32_t it_readbits(int8_t n, uint32_t *bitbuf, uint32_t *bitnum, const uint8_t **ibuf)
|
|
{
|
|
uint32_t value = 0;
|
|
uint32_t i = n;
|
|
|
|
// this could be better
|
|
while (i--) {
|
|
if (!*bitnum) {
|
|
*bitbuf = *(*ibuf)++;
|
|
*bitnum = 8;
|
|
}
|
|
value >>= 1;
|
|
value |= (*bitbuf) << 31;
|
|
(*bitbuf) >>= 1;
|
|
(*bitnum)--;
|
|
}
|
|
return value >> (32 - n);
|
|
}
|
|
|
|
|
|
uint32_t it_decompress8(void *dest, uint32_t len, const void *file, uint32_t filelen, int it215, int channels)
|
|
{
|
|
const uint8_t *filebuf; // source buffer containing compressed sample data
|
|
const uint8_t *srcbuf; // current position in source buffer
|
|
int8_t *destpos; // position in destination buffer which will be returned
|
|
uint16_t blklen; // length of compressed data block in samples
|
|
uint16_t blkpos; // position in block
|
|
uint8_t width; // actual "bit width"
|
|
uint16_t value; // value read from file to be processed
|
|
int8_t d1, d2; // integrator buffers (d2 for it2.15)
|
|
int8_t v; // sample value
|
|
uint32_t bitbuf, bitnum; // state for it_readbits
|
|
|
|
filebuf = srcbuf = (const uint8_t *) file;
|
|
destpos = (int8_t *) dest;
|
|
|
|
// now unpack data till the dest buffer is full
|
|
while (len) {
|
|
// read a new block of compressed data and reset variables
|
|
// block layout: word size, <size> bytes data
|
|
if (srcbuf + 2 > filebuf + filelen
|
|
|| srcbuf + 2 + (srcbuf[0] | (srcbuf[1] << 8)) > filebuf + filelen) {
|
|
// truncated!
|
|
return srcbuf - filebuf;
|
|
}
|
|
srcbuf += 2;
|
|
bitbuf = bitnum = 0;
|
|
|
|
blklen = MIN(0x8000, len);
|
|
blkpos = 0;
|
|
|
|
width = 9; // start with width of 9 bits
|
|
d1 = d2 = 0; // reset integrator buffers
|
|
|
|
// now uncompress the data block
|
|
while (blkpos < blklen) {
|
|
if (width > 9) {
|
|
// illegal width, abort
|
|
printf("Illegal bit width %d for 8-bit sample\n", width);
|
|
return srcbuf - filebuf;
|
|
}
|
|
value = it_readbits(width, &bitbuf, &bitnum, &srcbuf);
|
|
|
|
if (width < 7) {
|
|
// method 1 (1-6 bits)
|
|
// check for "100..."
|
|
if (value == 1 << (width - 1)) {
|
|
// yes!
|
|
value = it_readbits(3, &bitbuf, &bitnum, &srcbuf) + 1; // read new width
|
|
width = (value < width) ? value : value + 1; // and expand it
|
|
continue; // ... next value
|
|
}
|
|
} else if (width < 9) {
|
|
// method 2 (7-8 bits)
|
|
uint8_t border = (0xFF >> (9 - width)) - 4; // lower border for width chg
|
|
if (value > border && value <= (border + 8)) {
|
|
value -= border; // convert width to 1-8
|
|
width = (value < width) ? value : value + 1; // and expand it
|
|
continue; // ... next value
|
|
}
|
|
} else {
|
|
// method 3 (9 bits)
|
|
// bit 8 set?
|
|
if (value & 0x100) {
|
|
width = (value + 1) & 0xff; // new width...
|
|
continue; // ... and next value
|
|
}
|
|
}
|
|
|
|
// now expand value to signed byte
|
|
if (width < 8) {
|
|
uint8_t shift = 8 - width;
|
|
v = (value << shift);
|
|
v >>= shift;
|
|
} else {
|
|
v = (int8_t) value;
|
|
}
|
|
|
|
// integrate upon the sample values
|
|
d1 += v;
|
|
d2 += d1;
|
|
|
|
// .. and store it into the buffer
|
|
*destpos = it215 ? d2 : d1;
|
|
destpos += channels;
|
|
blkpos++;
|
|
}
|
|
|
|
// now subtract block length from total length and go on
|
|
len -= blklen;
|
|
}
|
|
return srcbuf - filebuf;
|
|
}
|
|
|
|
// Mostly the same as above.
|
|
uint32_t it_decompress16(void *dest, uint32_t len, const void *file, uint32_t filelen, int it215, int channels)
|
|
{
|
|
const uint8_t *filebuf; // source buffer containing compressed sample data
|
|
const uint8_t *srcbuf; // current position in source buffer
|
|
int16_t *destpos; // position in destination buffer which will be returned
|
|
uint16_t blklen; // length of compressed data block in samples
|
|
uint16_t blkpos; // position in block
|
|
uint8_t width; // actual "bit width"
|
|
uint32_t value; // value read from file to be processed
|
|
int16_t d1, d2; // integrator buffers (d2 for it2.15)
|
|
int16_t v; // sample value
|
|
uint32_t bitbuf, bitnum; // state for it_readbits
|
|
|
|
filebuf = srcbuf = (const uint8_t *) file;
|
|
destpos = (int16_t *) dest;
|
|
|
|
// now unpack data till the dest buffer is full
|
|
while (len) {
|
|
// read a new block of compressed data and reset variables
|
|
// block layout: word size, <size> bytes data
|
|
if (srcbuf + 2 > filebuf + filelen
|
|
|| srcbuf + 2 + (srcbuf[0] | (srcbuf[1] << 8)) > filebuf + filelen) {
|
|
// truncated!
|
|
return srcbuf - filebuf;
|
|
}
|
|
srcbuf += 2;
|
|
|
|
bitbuf = bitnum = 0;
|
|
|
|
blklen = MIN(0x4000, len); // 0x4000 samples => 0x8000 bytes again
|
|
blkpos = 0;
|
|
|
|
width = 17; // start with width of 17 bits
|
|
d1 = d2 = 0; // reset integrator buffers
|
|
|
|
// now uncompress the data block
|
|
while (blkpos < blklen) {
|
|
if (width > 17) {
|
|
// illegal width, abort
|
|
printf("Illegal bit width %d for 16-bit sample\n", width);
|
|
return srcbuf - filebuf;
|
|
}
|
|
value = it_readbits(width, &bitbuf, &bitnum, &srcbuf);
|
|
|
|
if (width < 7) {
|
|
// method 1 (1-6 bits)
|
|
// check for "100..."
|
|
if (value == (uint32_t) 1 << (width - 1)) {
|
|
// yes!
|
|
value = it_readbits(4, &bitbuf, &bitnum, &srcbuf) + 1; // read new width
|
|
width = (value < width) ? value : value + 1; // and expand it
|
|
continue; // ... next value
|
|
}
|
|
} else if (width < 17) {
|
|
// method 2 (7-16 bits)
|
|
uint16_t border = (0xFFFF >> (17 - width)) - 8; // lower border for width chg
|
|
if (value > border && value <= (uint32_t) (border + 16)) {
|
|
value -= border; // convert width to 1-8
|
|
width = (value < width) ? value : value + 1; // and expand it
|
|
continue; // ... next value
|
|
}
|
|
} else {
|
|
// method 3 (17 bits)
|
|
// bit 16 set?
|
|
if (value & 0x10000) {
|
|
width = (value + 1) & 0xff; // new width...
|
|
continue; // ... and next value
|
|
}
|
|
}
|
|
|
|
// now expand value to signed word
|
|
if (width < 16) {
|
|
uint8_t shift = 16 - width;
|
|
v = (value << shift);
|
|
v >>= shift;
|
|
} else {
|
|
v = (int16_t) value;
|
|
}
|
|
|
|
// integrate upon the sample values
|
|
d1 += v;
|
|
d2 += d1;
|
|
|
|
// .. and store it into the buffer
|
|
*destpos = it215 ? d2 : d1;
|
|
destpos += channels;
|
|
blkpos++;
|
|
}
|
|
|
|
// now subtract block length from total length and go on
|
|
len -= blklen;
|
|
}
|
|
return srcbuf - filebuf;
|
|
}
|