[gdk-pixbuf/gdk-pixbuf-2-24] Fix handling of options when saving pngs

[Matthias Clasen <matthiasc src gnome org>]

commit 23cdf123efacbdaa47e4d73cdc74e5a3356b18b1
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Dec 16 16:38:41 2011 -0500

    Fix handling of options when saving pngs
    
    The png loader treats its options in two passes, the first pass
    counts and verifies them, the second pass converts text options.
    This worked ok when only text was understood, but with the introduction
    of compression and icc-profile as supported options, the two loops
    can now get out of sync when the text options are not all at the
    beginning.
    
    Fix this by skipping non-text options in the second loop, just
    as we do in the first loop.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=620911

 gdk-pixbuf/io-png.c |   25 ++++++++++++++++++-------
 1 files changed, 18 insertions(+), 7 deletions(-)
---
diff --git a/gdk-pixbuf/io-png.c b/gdk-pixbuf/io-png.c
index 76f3304..b2032c4 100644
--- a/gdk-pixbuf/io-png.c
+++ b/gdk-pixbuf/io-png.c
@@ -923,11 +923,19 @@ static gboolean real_save_png (GdkPixbuf        *pixbuf,
        }
 
        if (num_keys > 0) {
+               gchar **kiter = keys;
+               gchar **viter = values;
+
                text_ptr = g_new0 (png_text, num_keys);
                for (i = 0; i < num_keys; i++) {
+                       if (strncmp (*kiter, "tEXt::", 6) != 0) {
+                                kiter++;
+                                viter++;
+                       }
+
                        text_ptr[i].compression = PNG_TEXT_COMPRESSION_NONE;
-                       text_ptr[i].key  = keys[i] + 6;
-                       text_ptr[i].text = g_convert (values[i], -1, 
+                       text_ptr[i].key  = *kiter + 6;
+                       text_ptr[i].text = g_convert (*viter, -1, 
                                                      "ISO-8859-1", "UTF-8", 
                                                      NULL, &text_ptr[i].text_length, 
                                                      NULL);
@@ -935,7 +943,7 @@ static gboolean real_save_png (GdkPixbuf        *pixbuf,
 #ifdef PNG_iTXt_SUPPORTED 
                        if (!text_ptr[i].text) {
                                text_ptr[i].compression = PNG_ITXT_COMPRESSION_NONE;
-                               text_ptr[i].text = g_strdup (values[i]);
+                               text_ptr[i].text = g_strdup (*viter);
                                text_ptr[i].text_length = 0;
                                text_ptr[i].itxt_length = strlen (text_ptr[i].text);
                                text_ptr[i].lang = NULL;
@@ -944,16 +952,19 @@ static gboolean real_save_png (GdkPixbuf        *pixbuf,
 #endif
 
                        if (!text_ptr[i].text) {
+                               gint j;
                                g_set_error (error,
                                             GDK_PIXBUF_ERROR,
                                             GDK_PIXBUF_ERROR_BAD_OPTION,
-                                            _("Value for PNG text chunk %s cannot be converted to ISO-8859-1 encoding."), keys[i] + 6);
-                               num_keys = i;
-                               for (i = 0; i < num_keys; i++)
-                                       g_free (text_ptr[i].text);
+                                            _("Value for PNG text chunk %s cannot be converted to ISO-8859-1 encoding."), *kiter + 6);
+                               for (j = 0; j < i; j++)
+                                       g_free (text_ptr[j].text);
                                g_free (text_ptr);
                                return FALSE;
                        }
+
+                        kiter++;
+                        viter++;
                }
        }