Introduce text_segment structure and API

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

include/vlc_text_style.h

@@ -89,6 +89,26 @@ typedef struct
 
 #define STYLE_DEFAULT_FONT_SIZE 22
 
+
+typedef struct text_segment_t text_segment_t;
+/**
+ * Text segment for subtitles
+ *
+ * This structure is used to store a formatted text, with mixed styles
+ * Every segment is comprised of one text and a unique style
+ *
+ * On style change, a new segment is created with the next part of text
+ * and the new style, and chained to the list
+ *
+ * Create with text_segment_New and clean the chain with
+ * text_segment_ChainDelete
+ */
+struct text_segment_t {
+    char *psz_text;                   /**< text string of the segment */
+    text_style_t *style;              /**< style applied to this segment */
+    text_segment_t *p_next;           /**< next segment */
+};
+
 /**
  * Create a default text style
  */
@@ -109,6 +129,31 @@ VLC_API text_style_t * text_style_Duplicate( const text_style_t * );
  */
 VLC_API void text_style_Delete( text_style_t * );
 
+/**
+ * This function will create a new text segment.
+ *
+ * You should use text_segment_ChainDelete to destroy it, to clean all
+ * the linked segments.
+ *
+ * This duplicates the string passed as argument
+ */
+VLC_API text_segment_t *text_segment_New( const char * );
+
+/**
+ * This function will destroy a list of text segments allocated
+ * by text_segment_New.
+ *
+ * You may pass it NULL.
+ */
+VLC_API void text_segment_ChainDelete( text_segment_t * );
+
+/**
+ * This function will copy a text_segment and its chain into a new one
+ *
+ * You may give it NULL, but it will return NULL.
+ */
+VLC_API text_segment_t * text_segment_Copy( text_segment_t * );
+
 #ifdef __cplusplus
 }
 #endif

src/libvlccore.sym

@@ -418,6 +418,9 @@ subpicture_region_ChainDelete
 subpicture_region_Copy
 subpicture_region_Delete
 subpicture_region_New
+text_segment_New
+text_segment_ChainDelete
+text_segment_Copy
 vlc_tls_ClientCreate
 vlc_tls_Delete
 vlc_tls_ClientSessionCreate

src/misc/text_style.c

@@ -94,3 +94,45 @@ void text_style_Delete( text_style_t *p_style )
     free( p_style );
 }
 
+text_segment_t *text_segment_New( const char *psz_text )
+{
+    text_segment_t* segment = calloc( 1, sizeof(*segment) );
+    if( !segment )
+        return NULL;
+
+    segment->psz_text = strdup( psz_text );
+
+    return segment;
+}
+
+void text_segment_ChainDelete( text_segment_t *segment )
+{
+    while( segment != NULL )
+    {
+        text_segment_t *p_next = segment->p_next;
+
+        free( segment->psz_text );
+        //text_style_Delete( segment->style );
+        free( segment );
+
+        segment = p_next;
+    }
+}
+
+text_segment_t *text_segment_Copy( text_segment_t *p_src )
+{
+    text_segment_t *p_dst = NULL, *p_dst0 = NULL;
+
+    while( p_src && p_src->p_next ) {
+        text_segment_t *p_next = text_segment_New( p_src->psz_text );
+        p_src = p_src->p_next;
+
+        if( p_dst == NULL )
+            p_dst = p_dst0 = p_next;
+        else
+            p_dst->p_next = p_next;
+    }
+
+    return p_dst0;
+}
+