[vlc-devel] [VLC 3.0 PATCH] freetype: use UCS-4 on OS/2

[KO Myung-Hun]

OS/2 usesd UCS-2 whose data type was uint16_t with 2-bytes size.
However, FriBidi APIs expects FriBidiChar which is 4-bytes size. This
dismatch leads to unexpected behaviors such as corruption of a subtitle
text or even SIGSEGV.
And additional code paths for OS/2 are not necessary any more with this
patch.
---
 modules/text_renderer/freetype/freetype.c    | 38 +++++++++++++++++++-
 modules/text_renderer/freetype/freetype.h    |  3 +-
 modules/text_renderer/freetype/text_layout.c |  7 ----
 3 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/modules/text_renderer/freetype/freetype.c b/modules/text_renderer/freetype/freetype.c
index 32f1ea403b..79504d38ac 100644
--- a/modules/text_renderer/freetype/freetype.c
+++ b/modules/text_renderer/freetype/freetype.c
@@ -1049,6 +1049,42 @@ static void FreeStylesArray( text_style_t **pp_styles, size_t i_styles )
     free( pp_styles );
 }
 
+#ifdef __OS2__
+static void *ToUCS4( const char *in, size_t *outsize )
+{
+    uint16_t *psz_ucs2;
+    size_t i_ucs4_bytes;
+    uni_char_t *psz_ucs4;
+    int i_len;
+
+    psz_ucs2 = ToCharset( FREETYPE_TO_UCS, in, outsize );
+    if( !psz_ucs2 )
+        return NULL;
+
+    i_ucs4_bytes = *outsize * 2;
+    /* Realloc including NULL-terminator */
+    psz_ucs4 = realloc( psz_ucs2, i_ucs4_bytes + sizeof( *psz_ucs4 ) );
+    if( unlikely( !psz_ucs4 ) )
+    {
+        free( psz_ucs2 );
+
+        return NULL;
+    }
+
+    psz_ucs2 = ( uint16_t * )psz_ucs4;
+    i_len = i_ucs4_bytes / sizeof( *psz_ucs4 );
+    /* Copy including NULL-terminator */
+    for( int i = i_len; i >= 0; --i )
+        psz_ucs4[ i ] = psz_ucs2[ i ];
+
+    *outsize = i_ucs4_bytes;
+
+    return psz_ucs4;
+}
+#else
+# define ToUCS4( in, outsize ) ToCharset( FREETYPE_TO_UCS, ( in ), ( outsize ))
+#endif
+
 static uni_char_t* SegmentsToTextAndStyles( filter_t *p_filter, const text_segment_t *p_segment, size_t *pi_string_length,
                                             text_style_t ***ppp_styles, size_t *pi_styles )
 {
@@ -1062,7 +1098,7 @@ static uni_char_t* SegmentsToTextAndStyles( filter_t *p_filter, const text_segme
         if( !s->psz_text || !s->psz_text[0] )
             continue;
         size_t i_string_bytes = 0;
-        uni_char_t *psz_tmp = ToCharset( FREETYPE_TO_UCS, s->psz_text, &i_string_bytes );
+        uni_char_t *psz_tmp = ToUCS4( s->psz_text, &i_string_bytes );
         if( !psz_tmp )
         {
             free( psz_uni );
diff --git a/modules/text_renderer/freetype/freetype.h b/modules/text_renderer/freetype/freetype.h
index b0ef9cf178..df2e809ff0 100644
--- a/modules/text_renderer/freetype/freetype.h
+++ b/modules/text_renderer/freetype/freetype.h
@@ -54,11 +54,10 @@
 # define FT_MulFix(v, s) (((v)*(s))>>16)
 #endif
 
+typedef uint32_t uni_char_t;
 #ifdef __OS2__
-typedef uint16_t uni_char_t;
 # define FREETYPE_TO_UCS    "UCS-2LE"
 #else
-typedef uint32_t uni_char_t;
 # if defined(WORDS_BIGENDIAN)
 #  define FREETYPE_TO_UCS   "UCS-4BE"
 # else
diff --git a/modules/text_renderer/freetype/text_layout.c b/modules/text_renderer/freetype/text_layout.c
index 4dce1e30ba..8bac0d91bc 100644
--- a/modules/text_renderer/freetype/text_layout.c
+++ b/modules/text_renderer/freetype/text_layout.c
@@ -735,17 +735,10 @@ static int ShapeParagraphHarfBuzz( filter_t *p_filter,
 
         hb_buffer_set_direction( p_run->p_buffer, p_run->direction );
         hb_buffer_set_script( p_run->p_buffer, p_run->script );
-#ifdef __OS2__
-        hb_buffer_add_utf16( p_run->p_buffer,
-                             p_paragraph->p_code_points + p_run->i_start_offset,
-                             p_run->i_end_offset - p_run->i_start_offset, 0,
-                             p_run->i_end_offset - p_run->i_start_offset );
-#else
         hb_buffer_add_utf32( p_run->p_buffer,
                              p_paragraph->p_code_points + p_run->i_start_offset,
                              p_run->i_end_offset - p_run->i_start_offset, 0,
                              p_run->i_end_offset - p_run->i_start_offset );
-#endif
         hb_shape( p_run->p_hb_font, p_run->p_buffer, 0, 0 );
         p_run->p_glyph_infos =
             hb_buffer_get_glyph_infos( p_run->p_buffer, &p_run->i_glyph_count );
-- 
2.30.0