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  /* only for the dllexport defs */ 
 
#include  
#include  
 
#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 & 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(&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) & 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 ((&mp->fr)->do_layer(&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 && 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); 
}