avcodec/vlc: Use structure instead of VLC_TYPE array as VLC element

In C, qualifiers for arrays are broken:
const VLC_TYPE (*foo)[2] is a pointer to an array of two const VLC_TYPE
elements and unfortunately this is not compatible with a pointer
to a const array of two VLC_TYPE, because the latter does not exist
as array types are never qualified (the qualifier applies to the base
type instead). This is the reason why get_vlc2() doesn't accept
a const VLC table despite not modifying the table at all, as
there is no automatic conversion from VLC_TYPE (*)[2] to
const VLC_TYPE (*)[2].

Fix this by using a structure VLCElem for the VLC table.
This also has the advantage of making it clear which
element is which.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 8 insertions, 9 deletions

diff --git a/libavcodec/tableprint_vlc.h b/libavcodec/tableprint_vlc.h
index d53ae5799f..b97c1f9cfb 100644
--- a/libavcodec/tableprint_vlc.h
+++ b/libavcodec/tableprint_vlc.h
@@ -39,23 +39,22 @@
 #include "libavutil/reverse.c"
 #include "vlc.c"
 
-#define REPLACE_DEFINE2(type) write_##type##_array
-#define REPLACE_DEFINE(type) REPLACE_DEFINE2(type)
-static void write_VLC_TYPE_array(const VLC_TYPE *p, int s) {
-    REPLACE_DEFINE(VLC_TYPE)(p, s);
-}
-
-WRITE_2D_FUNC(VLC_TYPE)
+// The following will have to be modified if VLCBaseType changes.
+WRITE_1D_FUNC_ARGV(VLCElem, 3, "{ .sym =%5" PRId16 ", .len =%2"PRIi16 " }",
+                   data[i].sym, data[i].len)
 
-static void write_vlc_type(const VLC *vlc, VLC_TYPE (*base_table)[2], const char *base_table_name)
+static void write_vlc_type(const VLC *vlc, const VLCElem *base_table, const char *base_table_name)
 {
     printf("    .bits = %i,\n", vlc->bits);
     // Unfortunately need to cast away const currently
-    printf("    .table = (VLC_TYPE (*)[2])(%s + 0x%x),\n", base_table_name, (int)(vlc->table - base_table));
+    printf("    .table = (VLCElem *)(%s + 0x%x),\n", base_table_name, (int)(vlc->table - base_table));
     printf("    .table_size = 0x%x,\n", vlc->table_size);
     printf("    .table_allocated = 0x%x,\n", vlc->table_allocated);
 }
 
+#define WRITE_VLC_TABLE(prefix, name)                   \
+    WRITE_ARRAY(prefix, VLCElem, name)
+
 #define WRITE_VLC_TYPE(prefix, name, base_table)        \
     do {                                                \
         printf(prefix" VLC "#name" = {\n");             \