[PATCH] Make font subsetting output fonts in order of the font subset id

[Adrian Johnson]

This ensures that PS/PDF output is always the same for the same cairo
input. Previously the order of the embedded fonts depended on the hash
key of the fonts which depended on the memory location of fonts.
---
 src/cairo-scaled-font-subsets.c |   58 +++++++++++++++++++++++++++------------
 1 files changed, 40 insertions(+), 18 deletions(-)

diff --git a/src/cairo-scaled-font-subsets.c b/src/cairo-scaled-font-subsets.c
index ee29f89..79bc097 100644
--- a/src/cairo-scaled-font-subsets.c
+++ b/src/cairo-scaled-font-subsets.c
@@ -53,18 +53,6 @@ typedef enum {
     CAIRO_SUBSETS_COMPOSITE
 } cairo_subsets_type_t;
 
-struct _cairo_scaled_font_subsets {
-    cairo_subsets_type_t type;
-
-    int max_glyphs_per_unscaled_subset_used;
-    cairo_hash_table_t *unscaled_sub_fonts;
-
-    int max_glyphs_per_scaled_subset_used;
-    cairo_hash_table_t *scaled_sub_fonts;
-
-    int num_sub_fonts;
-};
-
 typedef struct _cairo_sub_font {
     cairo_hash_entry_t base;
 
@@ -79,8 +67,25 @@ typedef struct _cairo_sub_font {
     int max_glyphs_per_subset;
 
     cairo_hash_table_t *sub_font_glyphs;
+    struct _cairo_sub_font *next;
 } cairo_sub_font_t;
 
+struct _cairo_scaled_font_subsets {
+    cairo_subsets_type_t type;
+
+    int max_glyphs_per_unscaled_subset_used;
+    cairo_hash_table_t *unscaled_sub_fonts;
+    cairo_sub_font_t *unscaled_sub_fonts_list;
+    cairo_sub_font_t *unscaled_sub_fonts_list_end;
+
+    int max_glyphs_per_scaled_subset_used;
+    cairo_hash_table_t *scaled_sub_fonts;
+    cairo_sub_font_t *scaled_sub_fonts_list;
+    cairo_sub_font_t *scaled_sub_fonts_list_end;
+
+    int num_sub_fonts;
+};
+
 typedef struct _cairo_sub_font_glyph {
     cairo_hash_entry_t base;
 
@@ -252,6 +257,7 @@ _cairo_sub_font_create (cairo_scaled_font_subsets_t	*parent,
 	free (sub_font);
 	return _cairo_error (CAIRO_STATUS_NO_MEMORY);
     }
+    sub_font->next = NULL;
 
     /* Reserve first glyph in subset for the .notdef glyph */
     status = _cairo_sub_font_map_glyph (sub_font, 0, &subset_glyph);
@@ -461,6 +467,8 @@ _cairo_scaled_font_subsets_create_internal (cairo_subsets_type_t type)
 	free (subsets);
 	return NULL;
     }
+    subsets->unscaled_sub_fonts_list = NULL;
+    subsets->unscaled_sub_fonts_list_end = NULL;
 
     subsets->scaled_sub_fonts = _cairo_hash_table_create (_cairo_sub_fonts_equal);
     if (! subsets->scaled_sub_fonts) {
@@ -468,6 +476,8 @@ _cairo_scaled_font_subsets_create_internal (cairo_subsets_type_t type)
 	free (subsets);
 	return NULL;
     }
+    subsets->scaled_sub_fonts_list = NULL;
+    subsets->scaled_sub_fonts_list_end = NULL;
 
     return subsets;
 }
@@ -611,11 +621,16 @@ _cairo_scaled_font_subsets_map_glyph (cairo_scaled_font_subsets_t	*subsets,
 
             status = _cairo_hash_table_insert (subsets->unscaled_sub_fonts,
                                                &sub_font->base);
+
             if (status) {
 		_cairo_sub_font_destroy (sub_font);
                 return status;
 	    }
-
+	    if (!subsets->unscaled_sub_fonts_list)
+		subsets->unscaled_sub_fonts_list = sub_font;
+	    else
+		subsets->unscaled_sub_fonts_list_end->next = sub_font;
+	    subsets->unscaled_sub_fonts_list_end = sub_font;
 	    subsets->num_sub_fonts++;
         }
     } else {
@@ -650,7 +665,11 @@ _cairo_scaled_font_subsets_map_glyph (cairo_scaled_font_subsets_t	*subsets,
 		_cairo_sub_font_destroy (sub_font);
                 return status;
 	    }
-
+	    if (!subsets->scaled_sub_fonts_list)
+		subsets->scaled_sub_fonts_list = sub_font;
+	    else
+		subsets->scaled_sub_fonts_list_end->next = sub_font;
+	    subsets->scaled_sub_fonts_list_end = sub_font;
 	    subsets->num_sub_fonts++;
         }
     }
@@ -667,6 +686,7 @@ _cairo_scaled_font_subsets_foreach_internal (cairo_scaled_font_subsets_t
                                              cairo_bool_t                              is_scaled)
 {
     cairo_sub_font_collection_t collection;
+    cairo_sub_font_t *sub_font;
 
     if (is_scaled)
         collection.glyphs_size = font_subsets->max_glyphs_per_scaled_subset_used;
@@ -685,12 +705,14 @@ _cairo_scaled_font_subsets_foreach_internal (cairo_scaled_font_subsets_t
     collection.status = CAIRO_STATUS_SUCCESS;
 
     if (is_scaled)
-        _cairo_hash_table_foreach (font_subsets->scaled_sub_fonts,
-                                   _cairo_sub_font_collect, &collection);
+	sub_font = font_subsets->scaled_sub_fonts_list;
     else
-        _cairo_hash_table_foreach (font_subsets->unscaled_sub_fonts,
-                                   _cairo_sub_font_collect, &collection);
+	sub_font = font_subsets->unscaled_sub_fonts_list;
 
+    while (sub_font) {
+	_cairo_sub_font_collect (sub_font, &collection);
+	sub_font = sub_font->next;
+    }
     free (collection.glyphs);
 
     return collection.status;
-- 
1.5.2.4


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