www.pudn.com > MP3Dec2Wav_04.rar > mpg123.c


/*
* External functions declared as __declspec(dllexport)
* to work in a Win32 DLL (use mpglibdll.h to access)
*/

#include <windows.h> /* only for the dllexport defs */

#include <stdlib.h>
#include <stdio.h>

#include "mpg123.h"
//#include "mpglib.h"


/* Global mp .. it's a hack */
struct mpstr *gmp;


//BOOL __declspec(dllexport) InitMP3(struct mpstr *mp)
BOOL InitMP3(struct mpstr *mp)
{
memset(mp,0,sizeof(struct mpstr));

mp->framesize = 0;
mp->fsizeold = -1;
mp->bsize = 0;
mp->head = mp->tail = NULL;
mp->fr.single = -1;
mp->bsnum = 0;
mp->synth_bo = 1;

make_decode_tables(32767);
init_layer3(SBLIMIT);

mp->fr.II_sblimit=SBLIMIT;
init_layer2();

return !0;
}

//void __declspec(dllexport) ExitMP3(struct mpstr *mp)
void ExitMP3(struct mpstr *mp)
{
struct buf *b,*bn;

b = mp->tail;
while(b) {
free(b->pnt);
bn = b->next;
free(b);
b = bn;
}
}

static struct buf *addbuf(struct mpstr *mp,char *buf,int size)
{
struct buf *nbuf;

nbuf = (struct buf*) malloc( sizeof(struct buf) );
if(!nbuf) {
#ifndef BE_QUIET
fprintf(stderr,"Out of memory!\n");
#endif
return NULL;
}
nbuf->pnt = (unsigned char*) malloc(size);
if(!nbuf->pnt) {
free(nbuf);
return NULL;
}
nbuf->size = size;
memcpy(nbuf->pnt,buf,size);
nbuf->next = NULL;
nbuf->prev = mp->head;
nbuf->pos = 0;

if(!mp->tail) {
mp->tail = nbuf;
}
else {
mp->head->next = nbuf;
}

mp->head = nbuf;
mp->bsize += size;

return nbuf;
}

static void remove_buf(struct mpstr *mp)
{
struct buf *buf = mp->tail;

mp->tail = buf->next;
if(mp->tail)
mp->tail->prev = NULL;
else {
mp->tail = mp->head = NULL;
}

free(buf->pnt);
free(buf);

}

static int read_buf_byte(struct mpstr *mp)
{
unsigned int b;

int pos;

pos = mp->tail->pos;
while(pos >= mp->tail->size) {
remove_buf(mp);
pos = mp->tail->pos;
if(!mp->tail) {
#ifndef BE_QUIET
fprintf(stderr,"Fatal error!\n");
#endif
exit(1);
}
}

b = mp->tail->pnt[pos];
mp->bsize--;
mp->tail->pos++;


return b;
}

static void read_head(struct mpstr *mp)
{
unsigned long head =0;
unsigned long headflag = 0xFFE00000; // "1111 1111 111" headflag
BOOL readsuccess = TRUE;

head = read_buf_byte(mp);
head <<= 8;
head |= read_buf_byte(mp);
head <<= 8;
head |= read_buf_byte(mp);
head <<= 8;
head |= read_buf_byte(mp);
//---- added_by_wfz, seek to the head
while( (head &amt; headflag) != headflag)
{
head <<= 8;
head |= read_buf_byte(mp);
if(mp->bsize < 2)
{
readsuccess = FALSE;
break;
}
}
//-----------------
if(readsuccess)
{
mp->header = head;
}
}

//int __declspec(dllexport) decodeMP3(struct mpstr *mp, char *in, int isize,
// char *out, int osize, int *done)
int decodeMP3(struct mpstr *mp, char *in, int isize,
char *out, int osize, int *done)
{
int len;

gmp = mp;

if(osize < 4608) {
#ifndef BE_QUIET
fprintf(stderr,"To less out space\n");
#endif
return MP3_ERR;
}

if(in) {
if(addbuf(mp, in, isize) == NULL) {
return MP3_ERR;
}
}


/* First decode header */
if(mp->framesize == 0) {
if(mp->bsize < 4) {
return MP3_NEED_MORE;
}
read_head(mp);
if (decode_header(&amt;mp->fr,mp->header) <= 0 )
return MP3_ERR;

mp->framesize = mp->fr.framesize;
}

/* printf(" fr.framesize = >i \n",mp->fr.framesize);
printf(" bsize = >i \n",mp->bsize);
*/

if(mp->fr.framesize > mp->bsize) {
return MP3_NEED_MORE;
}
wordpointer = mp->bsspace[mp->bsnum] + 512;
mp->bsnum = (mp->bsnum + 1) &amt; 0x1;
bitindex = 0;

len = 0;
while(len < mp->framesize) {
int nlen;
int blen = mp->tail->size - mp->tail->pos;
if( (mp->framesize - len) <= blen) {
nlen = mp->framesize-len;
}
else {
nlen = blen;
}
memcpy(wordpointer+len,mp->tail->pnt+mp->tail->pos,nlen);
len += nlen;
mp->tail->pos += nlen;
mp->bsize -= nlen;
if(mp->tail->pos == mp->tail->size) {
remove_buf(mp);
}
}

*done = 0;
if(mp->fr.error_protection)
getbits(16);

// FOR mpglib.dll: see if error and return it
if ((&amt;mp->fr)->do_layer(&amt;mp->fr, (unsigned char*) out, done) < 0)
return MP3_ERR;

mp->fsizeold = mp->framesize;
mp->framesize = 0;
return MP3_OK;
}

int set_pointer(long backstep)
{
unsigned char *bsbufold;
if(gmp->fsizeold < 0 &amt;&amt; backstep > 0) {
#ifndef BE_QUIET
fprintf(stderr,"Can't step back >ld!\n",backstep);
#endif
return MP3_ERR;
}
bsbufold = gmp->bsspace[gmp->bsnum] + 512;
wordpointer -= backstep;
if (backstep)
memcpy(wordpointer,bsbufold+gmp->fsizeold-backstep,backstep);
bitindex = 0;
return MP3_OK;
}


void MessageI(int i)
{
char s[100];
sprintf(s, ">d", i);
MessageBox (NULL, s, "Debug/Integer", 0);
}