[Vorbis-dev] [Patch] Const correct tags functions

[Erik de Castro Lopo]

Hi all,

I tend to compile my code with all GCC warnings turned on. However,
when I do this :

    vorbis_comment_add_tag(&vdata->vc,"ENCODER","libsndfile");

I get the following warning messages:

    warning: passing argument 2 of 'vorbis_comment_add_tag' discards 
        qualifiers from pointer target type
    warning: passing argument 3 of 'vorbis_comment_add_tag' discards 
        qualifiers from pointer target type

The problem is that string literals like "ENCODER" are be const
char * which vorbis_comment_add_tag is prototyped as having char *
pointers, even though the strings pointed to are not modified.

The following patch (against SVN head) makes the libvorbis const
correct.

Cheers,
Erik

---------------8<---------------8<---------------8<---------------
--- include/vorbis/codec.h	(revision 13502)
+++ include/vorbis/codec.h	(working copy)
@@ -166,11 +166,11 @@
 extern void     vorbis_info_clear(vorbis_info *vi);
 extern int      vorbis_info_blocksize(vorbis_info *vi,int zo);
 extern void     vorbis_comment_init(vorbis_comment *vc);
-extern void     vorbis_comment_add(vorbis_comment *vc, char *comment);
+extern void     vorbis_comment_add(vorbis_comment *vc, const 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 int      vorbis_comment_query_count(vorbis_comment *vc, char *tag);
+				       const char *tag, const char *contents);
+extern char    *vorbis_comment_query(vorbis_comment *vc, const char *tag, int count);
+extern int      vorbis_comment_query_count(vorbis_comment *vc, const char *tag);
 extern void     vorbis_comment_clear(vorbis_comment *vc);
 
 extern int      vorbis_block_init(vorbis_dsp_state *v, vorbis_block *vb);
--- lib/info.c	(revision 13502)
+++ lib/info.c	(working copy)
@@ -59,7 +59,7 @@
   memset(vc,0,sizeof(*vc));
 }
 
-void vorbis_comment_add(vorbis_comment *vc,char *comment){
+void vorbis_comment_add(vorbis_comment *vc,const char *comment){
   vc->user_comments=_ogg_realloc(vc->user_comments,
 			    (vc->comments+2)*sizeof(*vc->user_comments));
   vc->comment_lengths=_ogg_realloc(vc->comment_lengths,
@@ -71,7 +71,7 @@
   vc->user_comments[vc->comments]=NULL;
 }
 
-void vorbis_comment_add_tag(vorbis_comment *vc, char *tag, char *contents){
+void vorbis_comment_add_tag(vorbis_comment *vc, const char *tag, const char *contents){
   char *comment=alloca(strlen(tag)+strlen(contents)+2); /* +2 for = and \0 */
   strcpy(comment, tag);
   strcat(comment, "=");
@@ -91,7 +91,7 @@
   return 0;
 }
 
-char *vorbis_comment_query(vorbis_comment *vc, char *tag, int count){
+char *vorbis_comment_query(vorbis_comment *vc, const char *tag, int count){
   long i;
   int found = 0;
   int taglen = strlen(tag)+1; /* +1 for the = we append */
@@ -112,7 +112,7 @@
   return NULL; /* didn't find anything */
 }
 
-int vorbis_comment_query_count(vorbis_comment *vc, char *tag){
+int vorbis_comment_query_count(vorbis_comment *vc, const char *tag){
   int i,count=0;
   int taglen = strlen(tag)+1; /* +1 for the = we append */
   char *fulltag = alloca(taglen+1);
---------------8<---------------8<---------------8<---------------


-- 
-----------------------------------------------------------------
Erik de Castro Lopo
-----------------------------------------------------------------
Journalist: Microsoft CEO Steve Ballmer has finally said Linux
            is the No. 1 threat to Windows. What's your response to that?
Linus     : "Tag, you're it." I don't care. They've had a lot of
            enemies in their time. Let them fight one enemy that
            doesn't care for a change.