ref: 6763cba31dea9a680d10d085e5e8e3f04e8cf3ce
dir: /src/hcom.c/
/*
* libSoX Macintosh HCOM format.
* These are really FSSD type files with Huffman compression,
* in MacBinary format.
* TODO: make the MacBinary format optional (so that .data files
* are also acceptable). (How to do this on output?)
*
* September 25, 1991
* Copyright 1991 Guido van Rossum And Sundry Contributors
* This source code is freely redistributable and may be used for
* any purpose. This copyright notice must be maintained.
* Guido van Rossum And Sundry Contributors are not responsible for
* the consequences of using this software.
*
* April 28, 1998 - Chris Bagwell (cbagwell@sprynet.com)
*
* Rearranged some functions so that they are declared before they are
* used, clearing up some compiler warnings. Because these functions
* passed floats, it helped some dumb compilers pass stuff on the
* stack correctly.
*
*/
#include "sox_i.h"
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
/* Dictionary entry for Huffman (de)compression */
typedef struct {
long frequ;
short dict_leftson;
short dict_rightson;
} dictent;
/* Private data used by reader */
struct readpriv {
/* Static data from the header */
dictent *dictionary;
int32_t checksum;
int deltacompression;
/* Engine state */
long huffcount;
long cksum;
int dictentry;
int nrbits;
uint32_t current;
short sample;
/* Dictionary */
dictent *de;
int32_t new_checksum;
int nbits;
int32_t curword;
};
static int startread(sox_format_t * ft)
{
struct readpriv *p = (struct readpriv *) ft->priv;
int i;
char buf[5];
uint32_t datasize, rsrcsize;
uint32_t huffcount, checksum, compresstype, divisor;
unsigned short dictsize;
int rc;
/* Skip first 65 bytes of header */
rc = sox_skipbytes(ft, 65);
if (rc)
return rc;
/* Check the file type (bytes 65-68) */
if (sox_reads(ft, buf, 4) == SOX_EOF || strncmp(buf, "FSSD", 4) != 0)
{
sox_fail_errno(ft,SOX_EHDR,"Mac header type is not FSSD");
return (SOX_EOF);
}
/* Skip to byte 83 */
rc = sox_skipbytes(ft, 83-69);
if (rc)
return rc;
/* Get essential numbers from the header */
sox_readdw(ft, &datasize); /* bytes 83-86 */
sox_readdw(ft, &rsrcsize); /* bytes 87-90 */
/* Skip the rest of the header (total 128 bytes) */
rc = sox_skipbytes(ft, 128-91);
if (rc != 0)
return rc;
/* The data fork must contain a "HCOM" header */
if (sox_reads(ft, buf, 4) == SOX_EOF || strncmp(buf, "HCOM", 4) != 0)
{
sox_fail_errno(ft,SOX_EHDR,"Mac data fork is not HCOM");
return (SOX_EOF);
}
/* Then follow various parameters */
sox_readdw(ft, &huffcount);
sox_readdw(ft, &checksum);
sox_readdw(ft, &compresstype);
if (compresstype > 1)
{
sox_fail_errno(ft,SOX_EHDR,"Bad compression type in HCOM header");
return (SOX_EOF);
}
sox_readdw(ft, &divisor);
if (divisor == 0 || divisor > 4)
{
sox_fail_errno(ft,SOX_EHDR,"Bad sampling rate divisor in HCOM header");
return (SOX_EOF);
}
sox_readw(ft, &dictsize);
/* Translate to sox parameters */
ft->encoding.encoding = SOX_ENCODING_HCOM;
ft->encoding.bits_per_sample = 8;
ft->signal.rate = 22050 / divisor;
ft->signal.channels = 1;
/* Allocate memory for the dictionary */
p->dictionary = (dictent *)xmalloc(511 * sizeof(dictent));
/* Read dictionary */
for(i = 0; i < dictsize; i++) {
sox_readw(ft, (unsigned short *)&(p->dictionary[i].dict_leftson));
sox_readw(ft, (unsigned short *)&(p->dictionary[i].dict_rightson));
sox_debug("%d %d",
p->dictionary[i].dict_leftson,
p->dictionary[i].dict_rightson);
}
rc = sox_skipbytes(ft, 1); /* skip pad byte */
if (rc)
return rc;
/* Initialized the decompression engine */
p->checksum = checksum;
p->deltacompression = compresstype;
if (!p->deltacompression)
sox_debug("HCOM data using value compression");
p->huffcount = huffcount;
p->cksum = 0;
p->dictentry = 0;
p->nrbits = -1; /* Special case to get first byte */
return (SOX_SUCCESS);
}
static sox_size_t read_samples(sox_format_t * ft, sox_sample_t *buf, sox_size_t len)
{
register struct readpriv *p = (struct readpriv *) ft->priv;
int done = 0;
unsigned char sample_rate;
if (p->nrbits < 0) {
/* The first byte is special */
if (p->huffcount == 0)
return 0; /* Don't know if this can happen... */
if (sox_readb(ft, &sample_rate) == SOX_EOF)
{
sox_fail_errno(ft,SOX_EOF,"unexpected EOF at start of HCOM data");
return (0);
}
p->sample = sample_rate;
*buf++ = SOX_UNSIGNED_8BIT_TO_SAMPLE(p->sample,);
p->huffcount--;
p->nrbits = 0;
done++;
len--;
if (len == 0)
return done;
}
while (p->huffcount > 0) {
if(p->nrbits == 0) {
sox_readdw(ft, &(p->current));
if (sox_eof(ft))
{
sox_fail_errno(ft,SOX_EOF,"unexpected EOF in HCOM data");
return (0);
}
p->cksum += p->current;
p->nrbits = 32;
}
if(p->current & 0x80000000) {
p->dictentry =
p->dictionary[p->dictentry].dict_rightson;
} else {
p->dictentry =
p->dictionary[p->dictentry].dict_leftson;
}
p->current = p->current << 1;
p->nrbits--;
if(p->dictionary[p->dictentry].dict_leftson < 0) {
short datum;
datum = p->dictionary[p->dictentry].dict_rightson;
if (!p->deltacompression)
p->sample = 0;
p->sample = (p->sample + datum) & 0xff;
p->huffcount--;
*buf++ = SOX_UNSIGNED_8BIT_TO_SAMPLE(p->sample,);
p->dictentry = 0;
done++;
len--;
if (len == 0)
break;
}
}
return done;
}
static int stopread(sox_format_t * ft)
{
register struct readpriv *p = (struct readpriv *) ft->priv;
if (p->huffcount != 0)
{
sox_fail_errno(ft,SOX_EFMT,"not all HCOM data read");
return (SOX_EOF);
}
if(p->cksum != p->checksum)
{
sox_fail_errno(ft,SOX_EFMT,"checksum error in HCOM data");
return (SOX_EOF);
}
free((char *)p->dictionary);
p->dictionary = NULL;
return (SOX_SUCCESS);
}
struct writepriv {
unsigned char *data; /* Buffer allocated with xmalloc */
sox_size_t size; /* Size of allocated buffer */
sox_size_t pos; /* Where next byte goes */
};
#define BUFINCR (10*BUFSIZ)
static int startwrite(sox_format_t * ft)
{
struct writepriv * p = (struct writepriv *) ft->priv;
p->size = BUFINCR;
p->pos = 0;
p->data = xmalloc(p->size);
return SOX_SUCCESS;
}
static sox_size_t write_samples(sox_format_t * ft, const sox_sample_t *buf, sox_size_t len)
{
struct writepriv *p = (struct writepriv *) ft->priv;
sox_sample_t datum;
sox_size_t i;
if (len == 0)
return 0;
if (p->pos + len > p->size) {
p->size = ((p->pos + len) / BUFINCR + 1) * BUFINCR;
p->data = (unsigned char *)xrealloc(p->data, p->size);
}
for (i = 0; i < len; i++) {
datum = *buf++;
p->data[p->pos++] = SOX_SAMPLE_TO_UNSIGNED_8BIT(datum, ft->clips);
}
return len;
}
static void makecodes(int e, int c, int s, int b, dictent newdict[511], long codes[256], long codesize[256])
{
assert(b); /* Prevent stack overflow */
if (newdict[e].dict_leftson < 0) {
codes[newdict[e].dict_rightson] = c;
codesize[newdict[e].dict_rightson] = s;
} else {
makecodes(newdict[e].dict_leftson, c, s + 1, b << 1, newdict, codes, codesize);
makecodes(newdict[e].dict_rightson, c + b, s + 1, b << 1, newdict, codes, codesize);
}
}
static void putcode(sox_format_t * ft, long codes[256], long codesize[256], unsigned c, unsigned char **df)
{
struct readpriv *p = (struct readpriv *) ft->priv;
long code, size;
int i;
code = codes[c];
size = codesize[c];
for(i = 0; i < size; i++) {
p->curword <<= 1;
if (code & 1)
p->curword += 1;
p->nbits++;
if (p->nbits == 32) {
put32_be(df, p->curword);
p->new_checksum += p->curword;
p->nbits = 0;
p->curword = 0;
}
code >>= 1;
}
}
static void compress(sox_format_t * ft, unsigned char **df, int32_t *dl)
{
struct readpriv *p = (struct readpriv *) ft->priv;
int samplerate;
unsigned char *datafork = *df;
unsigned char *ddf, *dfp;
short dictsize;
int frequtable[256];
long codes[256], codesize[256];
dictent newdict[511];
int i, sample, j, k, d, l, frequcount;
sample = *datafork;
memset(frequtable, 0, sizeof(frequtable));
memset(codes, 0, sizeof(codes));
memset(codesize, 0, sizeof(codesize));
memset(newdict, 0, sizeof(newdict));
for (i = 1; i < *dl; i++) {
d = (datafork[i] - (sample & 0xff)) & 0xff; /* creates absolute entries LMS */
sample = datafork[i];
datafork[i] = d;
assert(d >= 0 && d <= 255); /* check our table is accessed correctly */
frequtable[d]++;
}
p->de = newdict;
for (i = 0; i < 256; i++)
if (frequtable[i] != 0) {
p->de->frequ = -frequtable[i];
p->de->dict_leftson = -1;
p->de->dict_rightson = i;
p->de++;
}
frequcount = p->de - newdict;
for (i = 0; i < frequcount; i++) {
for (j = i + 1; j < frequcount; j++) {
if (newdict[i].frequ > newdict[j].frequ) {
k = newdict[i].frequ;
newdict[i].frequ = newdict[j].frequ;
newdict[j].frequ = k;
k = newdict[i].dict_leftson;
newdict[i].dict_leftson = newdict[j].dict_leftson;
newdict[j].dict_leftson = k;
k = newdict[i].dict_rightson;
newdict[i].dict_rightson = newdict[j].dict_rightson;
newdict[j].dict_rightson = k;
}
}
}
while (frequcount > 1) {
j = frequcount - 1;
p->de->frequ = newdict[j - 1].frequ;
p->de->dict_leftson = newdict[j - 1].dict_leftson;
p->de->dict_rightson = newdict[j - 1].dict_rightson;
l = newdict[j - 1].frequ + newdict[j].frequ;
for (i = j - 2; i >= 0 && l < newdict[i].frequ; i--)
newdict[i + 1] = newdict[i];
i = i + 1;
newdict[i].frequ = l;
newdict[i].dict_leftson = j;
newdict[i].dict_rightson = p->de - newdict;
p->de++;
frequcount--;
}
dictsize = p->de - newdict;
makecodes(0, 0, 0, 1, newdict, codes, codesize);
l = 0;
for (i = 0; i < 256; i++)
l += frequtable[i] * codesize[i];
l = (((l + 31) >> 5) << 2) + 24 + dictsize * 4;
sox_debug(" Original size: %6d bytes", *dl);
sox_debug("Compressed size: %6d bytes", l);
datafork = (unsigned char *)xmalloc((unsigned)l);
ddf = datafork + 22;
for(i = 0; i < dictsize; i++) {
put16_be(&ddf, newdict[i].dict_leftson);
put16_be(&ddf, newdict[i].dict_rightson);
}
*ddf++ = 0;
*ddf++ = *(*df)++;
p->new_checksum = 0;
p->nbits = 0;
p->curword = 0;
for (i = 1; i < *dl; i++)
putcode(ft, codes, codesize, *(*df)++, &ddf);
if (p->nbits != 0) {
codes[0] = 0;
codesize[0] = 32 - p->nbits;
putcode(ft, codes, codesize, 0, &ddf);
}
strncpy((char *)datafork, "HCOM", 4);
dfp = datafork + 4;
put32_be(&dfp, *dl);
put32_be(&dfp, p->new_checksum);
put32_be(&dfp, 1);
samplerate = 22050 / ft->signal.rate + .5;
put32_be(&dfp, samplerate);
put16_be(&dfp, dictsize);
*df = datafork; /* reassign passed pointer to new datafork */
*dl = l; /* and its compressed length */
}
/* End of hcom utility routines */
static int stopwrite(sox_format_t * ft)
{
struct writepriv *p = (struct writepriv *) ft->priv;
unsigned char *compressed_data = p->data;
sox_size_t compressed_len = p->pos;
int rc = SOX_SUCCESS;
/* Compress it all at once */
if (compressed_len)
compress(ft, &compressed_data, (int32_t *)&compressed_len);
free((char *)p->data);
/* Write the header */
sox_writebuf(ft, (void *)"\000\001A", 3); /* Dummy file name "A" */
sox_padbytes(ft, 65-3);
sox_writes(ft, "FSSD");
sox_padbytes(ft, 83-69);
sox_writedw(ft, compressed_len); /* compressed_data size */
sox_writedw(ft, 0); /* rsrc size */
sox_padbytes(ft, 128 - 91);
if (sox_error(ft)) {
sox_fail_errno(ft, errno, "write error in HCOM header");
rc = SOX_EOF;
} else if (sox_writebuf(ft, compressed_data, compressed_len) != compressed_len) {
/* Write the compressed_data fork */
sox_fail_errno(ft, errno, "can't write compressed HCOM data");
rc = SOX_EOF;
}
free((char *)compressed_data);
if (rc == SOX_SUCCESS)
/* Pad the compressed_data fork to a multiple of 128 bytes */
sox_padbytes(ft, 128u - (compressed_len % 128));
return rc;
}
SOX_FORMAT_HANDLER(hcom)
{
static char const * const names[] = {"hcom", NULL};
static sox_rate_t const write_rates[] = {22050,22050/2,22050/3,22050/4.,0};
static unsigned const write_encodings[] = {
SOX_ENCODING_HCOM, 8, 0, 0};
static sox_format_handler_t handler = {
"Mac FSSD files with Huffman compression",
names, SOX_FILE_BIG_END|SOX_FILE_MONO,
startread, read_samples, stopread,
startwrite, write_samples, stopwrite,
NULL, write_encodings, write_rates
};
return &handler;
}