A new abstracted interface to vorbisfile, using callback functions.

Now ov_open() just calls ov_open_callbacks() with appropriate arguments.
This also contains some minor changes that give a ~10% speedup with gcc,
and changes to vorbisfile.h to allow C++ compilation.

svn path=/trunk/vorbis/; revision=337

2 files changed, 69 insertions, 27 deletions

diff --git a/include/vorbis/vorbisfile.h b/include/vorbis/vorbisfile.h
index dda73efd..3a9e6aa0 100644
--- a/include/vorbis/vorbisfile.h
+++ b/include/vorbis/vorbisfile.h
@@ -12,18 +12,41 @@
  ********************************************************************
 
  function: stdio-based convenience library for opening/seeking/decoding
- last mod: $Id: vorbisfile.h,v 1.2 2000/01/28 09:05:02 xiphmont Exp $
+ last mod: $Id: vorbisfile.h,v 1.3 2000/04/21 09:35:03 msmith Exp $
 
  ********************************************************************/
 
 #ifndef _OV_FILE_H_
 #define _OV_FILE_H_
 
+#ifdef __cplusplus
+extern "C"
+{
+#endif /* __cplusplus */
+
 #include <stdio.h>
 #include "codec.h"
 
+/* The function prototypes for the callbacks are basically the same as for
+ * the stdio functions fread, fseek, fclose, ftell. 
+ * The one difference is that the FILE * arguments have been replaced with
+ * a void * - this is to be used as a pointer to whatever internal data these
+ * functions might need. In the stdio case, it's just a FILE * cast to a void *
+ * 
+ * If you use other functions, check the docs for these functions and return
+ * the right values. For seek_func(), you *MUST* return -1 if the stream is
+ * unseekable
+ */
+typedef struct {
+  size_t (*read_func)  (void *ptr, size_t size, size_t nmemb, void *datasource);
+  int    (*seek_func)  (void *datasource, long offset, int whence);
+  int    (*close_func) (void *datasource);
+  long   (*tell_func)  (void *datasource);
+} ov_callbacks;
+
+
 typedef struct {
-  FILE             *f;
+  void             *datasource; /* Pointer to a FILE *, etc. */
   int              seekable;
   long             offset;
   long             end;
@@ -35,9 +58,9 @@ typedef struct {
   long             *offsets;
   long             *dataoffsets;
   long             *serialnos;
-  int64_t           *pcmlengths;
+  int64_t          *pcmlengths;
   vorbis_info      *vi;
-  vorbis_comment  *vc;
+  vorbis_comment   *vc;
 
   /* Decoding working state local storage */
   int64_t          pcm_offset;
@@ -50,10 +73,14 @@ typedef struct {
   vorbis_dsp_state vd; /* central working state for the packet->PCM decoder */
   vorbis_block     vb; /* local working space for packet->PCM decode */
 
+  ov_callbacks callbacks;
+
 } OggVorbis_File;
 
 extern int ov_clear(OggVorbis_File *vf);
 extern int ov_open(FILE *f,OggVorbis_File *vf,char *initial,long ibytes);
+extern int ov_open_callback(void *datasource, OggVorbis_File *vf,
+		char *initial, long ibytes, ov_callbacks callbacks);
 
 extern long ov_bitrate(OggVorbis_File *vf,int i);
 extern long ov_streams(OggVorbis_File *vf);
@@ -78,11 +105,10 @@ extern vorbis_comment *ov_comment(OggVorbis_File *vf,int link);
 extern long ov_read(OggVorbis_File *vf,char *buffer,int length,
 		    int bigendianp,int word,int sgned,int *bitstream);
 
-#endif
-
-
-
-
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
 
+#endif
 
 
diff --git a/lib/vorbisfile.c b/lib/vorbisfile.c
index 055b3473..5cd7689f 100644
--- a/lib/vorbisfile.c
+++ b/lib/vorbisfile.c
@@ -12,7 +12,7 @@
  ********************************************************************
 
  function: stdio-based convenience library for opening/seeking/decoding
- last mod: $Id: vorbisfile.c,v 1.19 2000/04/03 09:45:55 xiphmont Exp $
+ last mod: $Id: vorbisfile.c,v 1.20 2000/04/21 09:35:03 msmith Exp $
 
  ********************************************************************/
 
@@ -58,15 +58,15 @@
 /* read a little more data from the file/pipe into the ogg_sync framer */
 #define CHUNKSIZE 4096
 static long _get_data(OggVorbis_File *vf){
-  char *buffer=ogg_sync_buffer(&vf->oy,4096);
-  long bytes=fread(buffer,1,4096,vf->f);
+  char *buffer=ogg_sync_buffer(&vf->oy,CHUNKSIZE);
+  long bytes=(vf->callbacks.read_func)(buffer,1,CHUNKSIZE,vf->datasource);
   ogg_sync_wrote(&vf->oy,bytes);
   return(bytes);
 }
 
 /* save a tiny smidge of verbosity to make the code more readable */
 static void _seek_helper(OggVorbis_File *vf,long offset){
-  fseek(vf->f,offset,SEEK_SET);
+  (vf->callbacks.seek_func)(vf->datasource, offset, SEEK_SET);
   vf->offset=offset;
   ogg_sync_reset(&vf->oy);
 }
@@ -338,8 +338,8 @@ static int _open_seekable(OggVorbis_File *vf){
   
   /* we can seek, so set out learning all about this file */
   vf->seekable=1;
-  fseek(vf->f,0,SEEK_END);
-  vf->offset=vf->end=ftell(vf->f);
+  (vf->callbacks.seek_func)(vf->datasource,0,SEEK_END);
+  vf->offset=vf->end=(vf->callbacks.tell_func)(vf->datasource);
   
   /* We get the offset for the last page of the physical bitstream.
      Most OggVorbis files will contain a single logical bitstream */
@@ -527,7 +527,7 @@ int ov_clear(OggVorbis_File *vf){
     if(vf->serialnos)free(vf->serialnos);
     if(vf->offsets)free(vf->offsets);
     ogg_sync_clear(&vf->oy);
-    if(vf->f)fclose(vf->f);
+    if(vf->datasource)(vf->callbacks.close_func)(vf->datasource);
     memset(vf,0,sizeof(OggVorbis_File));
   }
 #ifdef DEBUG_LEAKS
@@ -545,11 +545,25 @@ int ov_clear(OggVorbis_File *vf){
 */
 
 int ov_open(FILE *f,OggVorbis_File *vf,char *initial,long ibytes){
-  long offset=fseek(f,0,SEEK_CUR);
+  ov_callbacks callbacks = {
+    fread,
+    fseek,
+    fclose,
+    ftell};
+
+  return ov_open_callbacks((void *)f, vf, initial, ibytes, callbacks);
+}
+  
+
+int ov_open_callbacks(void *f,OggVorbis_File *vf,char *initial,long ibytes,
+    ov_callbacks callbacks)
+{
+  long offset=callbacks.seek_func(f,0,SEEK_CUR);
   int ret;
 
   memset(vf,0,sizeof(OggVorbis_File));
-  vf->f=f;
+  vf->datasource=f;
+  vf->callbacks = callbacks;
 
   /* init the framing state */
   ogg_sync_init(&vf->oy);
@@ -571,7 +585,7 @@ int ov_open(FILE *f,OggVorbis_File *vf,char *initial,long ibytes){
     ret=_open_nonseekable(vf);
   }
   if(ret){
-    vf->f=NULL;
+    vf->datasource=NULL;
     ov_clear(vf);
   }
   return(ret);
@@ -999,13 +1013,14 @@ long ov_read(OggVorbis_File *vf,char *buffer,int length,
 	
 	/* a tight loop to pack each size */
 	{
+	  int val;
 	  if(word==1){
 	    int off=(sgned?0:128);
 	    for(j=0;j<samples;j++)
 	      for(i=0;i<channels;i++){
-		int val=rint(pcm[i][j]*128.);
+		val=(int)(pcm[i][j]*128. + 0.5);
 		if(val>127)val=127;
-		if(val<-128)val=-128;
+		else if(val<-128)val=-128;
 		*buffer++=val+off;
 	      }
 	  }else{
@@ -1014,23 +1029,24 @@ long ov_read(OggVorbis_File *vf,char *buffer,int length,
 	    if(bigendianp){
 	      for(j=0;j<samples;j++)
 		for(i=0;i<channels;i++){
-		  int val=rint(pcm[i][j]*32768.);
+		  val=(int)(pcm[i][j]*32768. + 0.5);
 		  if(val>32767)val=32767;
-		  if(val<-32768)val=-32768;
+		  else if(val<-32768)val=-32768;
 		  val+=off;
 		  *buffer++=(val>>8);
 		  *buffer++=(val&0xff);
 		}
 	    }else{
+	      int val;
 	      for(j=0;j<samples;j++)
-		for(i=0;i<channels;i++){
-		  int val=rint(pcm[i][j]*32768.);
+	 	for(i=0;i<channels;i++){
+		  val=(int)(pcm[i][j]*32768. + 0.5);
 		  if(val>32767)val=32767;
-		  if(val<-32768)val=-32768;
+		  else if(val<-32768)val=-32768;
 		  val+=off;
 		  *buffer++=(val&0xff);
 		  *buffer++=(val>>8);
-		}
+	  	}
 
 	    }
 	  }