From 6774cb49c0b9234c6bdb35ad22065f569ec65cd8 Mon Sep 17 00:00:00 2001
From: Mike Smith <msmith@xiph.org>
Date: Sat, 29 Jul 2000 08:45:33 +0000
Subject: [PATCH] Added vorbis_comment_add_tag() and vorbis_comment_query() to
 give a nice interface to the 'tag' system we now have.

Also modified several bits of the generic comment interface so that one can get
at vital stuff like the LENGTH of comments (since 0-termination isn't guaranteed).

svn path=/trunk/vorbis/; revision=534
---
 include/vorbis/codec.h |  6 +++++-
 lib/info.c             | 47 +++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/include/vorbis/codec.h b/include/vorbis/codec.h
index 804a1eb..e75f05a 100644
--- a/include/vorbis/codec.h
+++ b/include/vorbis/codec.h
@@ -12,7 +12,7 @@
  ********************************************************************
 
  function: libvorbis codec headers
- last mod: $Id: codec.h,v 1.21 2000/07/12 09:36:17 xiphmont Exp $
+ last mod: $Id: codec.h,v 1.22 2000/07/29 08:45:33 msmith Exp $
 
  ********************************************************************/
 
@@ -339,6 +339,7 @@ typedef struct vorbis_comment{
   /* unlimited user comment fields.  libvorbis writes 'libvorbis'
      whatever vendor is set to in encode */
   char **user_comments;
+  int   *comment_lengths;
   int    comments;
   char  *vendor;
 
@@ -398,6 +399,9 @@ extern void     vorbis_info_init(vorbis_info *vi);
 extern void     vorbis_info_clear(vorbis_info *vi);
 extern void     vorbis_comment_init(vorbis_comment *vc);
 extern void     vorbis_comment_add(vorbis_comment *vc, char *comment); 
+extern void     vorbis_comment_add_tag(vorbis_comment *vc, 
+				       char *tag, char *contents);
+extern char    *vorbis_comment_query(vorbis_comment *vc, char *tag, int count);
 extern void     vorbis_comment_clear(vorbis_comment *vc);
 
 extern int      vorbis_block_init(vorbis_dsp_state *v, vorbis_block *vb);
diff --git a/lib/info.c b/lib/info.c
index 23ce375..175d7c8 100644
--- a/lib/info.c
+++ b/lib/info.c
@@ -12,7 +12,7 @@
  ********************************************************************
 
  function: maintain the info structure, info <-> header packets
- last mod: $Id: info.c,v 1.25 2000/07/07 00:53:10 xiphmont Exp $
+ last mod: $Id: info.c,v 1.26 2000/07/29 08:45:33 msmith Exp $
 
  ********************************************************************/
 
@@ -21,6 +21,7 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <ctype.h>
 #include "vorbis/codec.h"
 #include "vorbis/backends.h"
 #include "bitwise.h"
@@ -61,11 +62,51 @@ void vorbis_comment_init(vorbis_comment *vc){
 void vorbis_comment_add(vorbis_comment *vc,char *comment){
   vc->user_comments=realloc(vc->user_comments,
 			    (vc->comments+2)*sizeof(char *));
+  vc->comment_lengths=realloc(vc->comment_lengths,
+      			    (vc->comments+2)*sizeof(int));
   vc->user_comments[vc->comments]=strdup(comment);
+  vc->comment_lengths[vc->comments]=strlen(comment);
   vc->comments++;
   vc->user_comments[vc->comments]=NULL;
 }
 
+void vorbis_comment_add_tag(vorbis_comment *vc, char *tag, char *contents){
+  char *comment=alloca(strlen(tag)+strlen(contents)+2); /* +2 for = and \0 */
+  strcpy(comment, tag);
+  comment[strlen(tag)] = '=';
+  strcat(comment, contents);
+  vorbis_comment_add(vc, comment);
+}
+
+/* This is more or less the same as strncasecmp - but that doesn't exist
+ * everywhere, and this is a fairly trivial function, so we include it */
+static int tagcompare(const char *s1, const char *s2, int n){
+  int c=0;
+  while(c < n){
+    if(toupper(s1[c]) != toupper(s2[c]))
+      return !0;
+    c++;
+  }
+  return 0;
+}
+
+char *vorbis_comment_query(vorbis_comment *vc, char *tag, int count){
+  long i;
+  int found = 0;
+  int taglen = strlen(tag);
+  
+  for(i=0;i<vc->comments;i++){
+    if(!tagcompare(vc->user_comments[i], tag, taglen)){
+      if(count == found)
+	/* We return a pointer to the data, not a copy */
+      	return vc->user_comments[i] + taglen + 1;
+      else
+	found++;
+    }
+  }
+  return NULL; /* didn't find anything */
+}
+
 void vorbis_comment_clear(vorbis_comment *vc){
   if(vc){
     long i;
@@ -163,10 +204,12 @@ static int _vorbis_unpack_comment(vorbis_comment *vc,oggpack_buffer *opb){
   vc->comments=_oggpack_read(opb,32);
   if(vc->comments<0)goto err_out;
   vc->user_comments=calloc(vc->comments+1,sizeof(char **));
+  vc->comment_lengths=calloc(vc->comments+1, sizeof(int));
 	    
   for(i=0;i<vc->comments;i++){
     int len=_oggpack_read(opb,32);
     if(len<0)goto err_out;
+	vc->comment_lengths[i]=len;
     vc->user_comments[i]=calloc(len+1,1);
     _v_readstring(opb,vc->user_comments[i],len);
   }	  
@@ -360,7 +403,7 @@ static int _vorbis_pack_comment(oggpack_buffer *opb,vorbis_comment *vc){
     int i;
     for(i=0;i<vc->comments;i++){
       if(vc->user_comments[i]){
-	_oggpack_write(opb,strlen(vc->user_comments[i]),32);
+	_oggpack_write(opb,vc->comment_lengths[i],32);
 	_v_writestring(opb,vc->user_comments[i]);
       }else{
 	_oggpack_write(opb,0,32);
-- 
2.7.4