ref: dd448e56da071aebba7572eb6ea81788038133e8
dir: /src/xa.c/
/*
* xa.c Support for Maxis .XA file format
*
* Copyright (C) 2006 Dwayne C. Litzenberger <dlitz@dlitz.net>
*
* 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 library 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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301
* USA
*
*/
/* Thanks to Valery V. Anisimovsky <samael@avn.mccme.ru> for the
* "Maxis XA Audio File Format Description", dated 5-01-2002. */
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h> /* For SEEK_* defines if not found in stdio */
#endif
#include "st_i.h"
#define HNIBBLE(byte) (((byte) >> 4) & 0xf)
#define LNIBBLE(byte) ((byte) & 0xf)
/* .xa file header */
typedef struct {
char magic[4]; /* "XA\0\0", "XAI\0" (sound/speech), or "XAJ\0" (music) */
uint32_t outSize; /* decompressed size of the stream (in bytes) */
/* WAVEFORMATEX structure for the decompressed data */
uint16_t tag; /* 0x0001 - PCM data */
uint16_t channels; /* number of channels */
uint32_t sampleRate; /* sample rate (samples/sec) */
uint32_t avgByteRate; /* sampleRate * align */
uint16_t align; /* bits / 8 * channels */
uint16_t bits; /* 8 or 16 */
} xa_header_t;
typedef struct {
int32_t curSample; /* current sample */
int32_t prevSample; /* previous sample */
int32_t c1;
int32_t c2;
unsigned int shift;
} xa_state_t;
/* Private data for .xa file */
typedef struct xastuff {
xa_header_t header;
xa_state_t *state;
unsigned int blockSize;
unsigned int bufPos; /* position within the current block */
unsigned char *buf; /* buffer for the current block */
unsigned int bytesDecoded; /* number of decompressed bytes read */
} *xa_t;
/* coefficients for EA ADPCM */
static int32_t EA_ADPCM_Table[]= {
0, 240, 460, 392,
0, 0, -208, -220,
0, 1, 3, 4,
7, 8, 10, 11,
0, -1, -3, -4
};
/* Clip sample to 16 bits */
static inline int32_t clip16(int32_t sample)
{
if (sample > 32767) {
return 32767;
} else if (sample < -32768) {
return -32768;
} else {
return sample;
}
}
static int st_xastartread(ft_t ft)
{
xa_t xa = (xa_t) ft->priv;
char *magic = xa->header.magic;
/* Check for the magic value */
if (st_readbuf(ft, xa->header.magic, 1, 4) != 4 ||
(memcmp("XA\0\0", xa->header.magic, 4) != 0 &&
memcmp("XAI\0", xa->header.magic, 4) != 0 &&
memcmp("XAJ\0", xa->header.magic, 4) != 0))
{
st_fail_errno(ft, ST_EHDR, "XA: Header not found");
return ST_EOF;
}
/* Read the rest of the header */
if (st_readdw(ft, &xa->header.outSize) != ST_SUCCESS) return ST_EOF;
if (st_readw(ft, &xa->header.tag) != ST_SUCCESS) return ST_EOF;
if (st_readw(ft, &xa->header.channels) != ST_SUCCESS) return ST_EOF;
if (st_readdw(ft, &xa->header.sampleRate) != ST_SUCCESS) return ST_EOF;
if (st_readdw(ft, &xa->header.avgByteRate) != ST_SUCCESS) return ST_EOF;
if (st_readw(ft, &xa->header.align) != ST_SUCCESS) return ST_EOF;
if (st_readw(ft, &xa->header.bits) != ST_SUCCESS) return ST_EOF;
/* Output the data from the header */
st_debug("XA Header:");
st_debug(" szID: %02x %02x %02x %02x |%c%c%c%c|",
magic[0], magic[1], magic[2], magic[3],
(magic[0] >= 0x20 && magic[0] <= 0x7e) ? magic[0] : '.',
(magic[1] >= 0x20 && magic[1] <= 0x7e) ? magic[1] : '.',
(magic[2] >= 0x20 && magic[2] <= 0x7e) ? magic[2] : '.',
(magic[3] >= 0x20 && magic[3] <= 0x7e) ? magic[3] : '.');
st_debug(" dwOutSize: %u", xa->header.outSize);
st_debug(" wTag: 0x%04x", xa->header.tag);
st_debug(" wChannels: %u", xa->header.channels);
st_debug(" dwSampleRate: %u", xa->header.sampleRate);
st_debug(" dwAvgByteRate: %u", xa->header.avgByteRate);
st_debug(" wAlign: %u", xa->header.align);
st_debug(" wBits: %u", xa->header.bits);
/* Populate the st_soundstream structure */
ft->signal.encoding = ST_ENCODING_SIGN2;
if (ft->signal.size == -1 || ft->signal.size == (xa->header.bits >> 3)) {
ft->signal.size = xa->header.bits >> 3;
} else {
st_report("User options overriding size read in .xa header");
}
if (ft->signal.channels == 0 || ft->signal.channels == xa->header.channels) {
ft->signal.channels = xa->header.channels;
} else {
st_report("User options overriding channels read in .xa header");
}
if (ft->signal.rate == 0 || ft->signal.rate == xa->header.sampleRate) {
ft->signal.rate = xa->header.sampleRate;
} else {
st_report("User options overriding rate read in .xa header");
}
/* Check for supported formats */
if (ft->signal.size != 2) {
st_fail_errno(ft, ST_EFMT, "%d-bit sample resolution not supported.",
ft->signal.size << 3);
return ST_EOF;
}
/* Validate the header */
if (xa->header.bits != ft->signal.size << 3) {
st_report("Invalid sample resolution %d bits. Assuming %d bits.",
xa->header.bits, ft->signal.size << 3);
xa->header.bits = ft->signal.size << 3;
}
if (xa->header.align != ft->signal.size * xa->header.channels) {
st_report("Invalid sample alignment value %d. Assuming %d.",
xa->header.align, ft->signal.size * xa->header.channels);
xa->header.align = ft->signal.size * xa->header.channels;
}
if (xa->header.avgByteRate != (xa->header.align * xa->header.sampleRate)) {
st_report("Invalid dwAvgByteRate value %d. Assuming %d.",
xa->header.avgByteRate, xa->header.align * xa->header.sampleRate);
xa->header.avgByteRate = xa->header.align * xa->header.sampleRate;
}
/* Set up the block buffer */
xa->blockSize = ft->signal.channels * 0xf;
xa->bufPos = xa->blockSize;
/* Allocate memory for the block buffer */
xa->buf = (unsigned char *)xcalloc(1, xa->blockSize);
/* Allocate memory for the state */
xa->state = (xa_state_t *)xcalloc(sizeof(xa_state_t), ft->signal.channels);
/* Final initialization */
xa->bytesDecoded = 0;
return ST_SUCCESS;
}
/*
* Read up to len samples from a file, converted to signed longs.
* Return the number of samples read.
*/
static st_size_t st_xaread(ft_t ft, st_sample_t *buf, st_size_t len)
{
xa_t xa = (xa_t) ft->priv;
int32_t sample;
unsigned char inByte;
size_t i, done, bytes;
ft->st_errno = ST_SUCCESS;
done = 0;
while (done < len) {
if (xa->bufPos >= xa->blockSize) {
/* Read the next block */
bytes = st_readbuf(ft, xa->buf, 1, xa->blockSize);
if (bytes < xa->blockSize) {
if (st_eof(ft)) {
if (done > 0) {
return done;
}
st_fail_errno(ft,ST_EOF,"Premature EOF on .xa input file");
return ST_EOF;
} else {
/* error */
st_fail_errno(ft,ST_EOF,"read error on input stream");
return ST_EOF;
}
}
xa->bufPos = 0;
for (i = 0; i < ft->signal.channels; i++) {
inByte = xa->buf[i];
xa->state[i].c1 = EA_ADPCM_Table[HNIBBLE(inByte)];
xa->state[i].c2 = EA_ADPCM_Table[HNIBBLE(inByte) + 4];
xa->state[i].shift = LNIBBLE(inByte) + 8;
}
xa->bufPos += ft->signal.channels;
} else {
/* Process the block */
for (i = 0; i < ft->signal.channels && done < len; i++) {
/* high nibble */
sample = HNIBBLE(xa->buf[xa->bufPos+i]);
sample = (sample << 28) >> xa->state[i].shift;
sample = (sample +
xa->state[i].curSample * xa->state[i].c1 +
xa->state[i].prevSample * xa->state[i].c2 + 0x80) >> 8;
sample = clip16(sample);
xa->state[i].prevSample = xa->state[i].curSample;
xa->state[i].curSample = sample;
buf[done++] = ST_SIGNED_WORD_TO_SAMPLE(sample,);
xa->bytesDecoded += ft->signal.size;
}
for (i = 0; i < ft->signal.channels && done < len; i++) {
/* low nibble */
sample = LNIBBLE(xa->buf[xa->bufPos+i]);
sample = (sample << 28) >> xa->state[i].shift;
sample = (sample +
xa->state[i].curSample * xa->state[i].c1 +
xa->state[i].prevSample * xa->state[i].c2 + 0x80) >> 8;
sample = clip16(sample);
xa->state[i].prevSample = xa->state[i].curSample;
xa->state[i].curSample = sample;
buf[done++] = ST_SIGNED_WORD_TO_SAMPLE(sample,);
xa->bytesDecoded += ft->signal.size;
}
xa->bufPos += ft->signal.channels;
}
}
if (done == 0) {
return ST_EOF;
}
return done;
}
static int st_xastopread(ft_t ft)
{
xa_t xa = (xa_t) ft->priv;
ft->st_errno = ST_SUCCESS;
/* Free memory */
free(xa->buf);
xa->buf = NULL;
free(xa->state);
xa->state = NULL;
return ST_SUCCESS;
}
static int st_xastartwrite(ft_t ft)
{
st_fail_errno(ft, ST_ENOTSUP, ".XA writing not supported");
return ST_EOF;
}
static st_size_t st_xawrite(ft_t ft, const st_sample_t *buf UNUSED, st_size_t len UNUSED)
{
st_fail_errno(ft, ST_ENOTSUP, ".XA writing not supported");
return ST_EOF;
}
static int st_xastopwrite(ft_t ft)
{
st_fail_errno(ft, ST_ENOTSUP, ".XA writing not supported");
return ST_EOF;
}
static int st_xaseek(ft_t ft, st_size_t offset)
{
return st_format_nothing_seek(ft, offset);
}
/* Maxis .xa */
static const char *xanames[] = {
"xa",
NULL
};
st_format_t st_xa_format = {
xanames,
NULL,
ST_FILE_LIT_END,
st_xastartread,
st_xaread,
st_xastopread,
st_xastartwrite,
st_xawrite,
st_xastopwrite,
st_xaseek
};
const st_format_t *st_xa_format_fn(void)
{
return &st_xa_format;
}