[gimp] Bug 731390 - XCF files have a max size of 4G

[Michael Natterer <mitch src gnome org>]

commit 829bad4063c5914e74ef9a4b988e0ee5bfaaae44
Author: Michael Natterer <mitch gimp org>
Date:   Thu Mar 23 13:16:13 2017 +0100

    Bug 731390 - XCF files have a max size of 4G
    
    Add support for 64 bit offsets to xcf_read_offset() and
    xcf_write_offset(), but don't use the feature yet.

 app/xcf/xcf-read.c  |   28 +++++++++++++++++++++-------
 app/xcf/xcf-write.c |   27 +++++++++++++++++++--------
 2 files changed, 40 insertions(+), 15 deletions(-)
---
diff --git a/app/xcf/xcf-read.c b/app/xcf/xcf-read.c
index 489ccb8..3431265 100644
--- a/app/xcf/xcf-read.c
+++ b/app/xcf/xcf-read.c
@@ -58,18 +58,32 @@ xcf_read_offset (XcfInfo *info,
                  goffset *data,
                  gint     count)
 {
-  guint   total = 0;
-  gint32 *int_offsets = g_alloca (count * sizeof (gint32));
+  guint total = 0;
 
   if (count > 0)
     {
-      total += xcf_read_int8 (info, (guint8 *) int_offsets, count * 4);
+      if (info->bytes_per_offset == 4)
+        {
+          gint32 *int_offsets = g_alloca (count * sizeof (gint32));
 
-      while (count--)
+          total += xcf_read_int8 (info, (guint8 *) int_offsets, count * 4);
+
+          while (count--)
+            {
+              *data = g_ntohl (*int_offsets);
+              int_offsets++;
+              data++;
+            }
+        }
+      else
         {
-          *data = g_ntohl (*int_offsets);
-          int_offsets++;
-          data++;
+          total += xcf_read_int8 (info, (guint8 *) data, count * 8);
+
+          while (count--)
+            {
+              *data = GINT64_FROM_BE (*data);
+              data++;
+            }
         }
     }
 
diff --git a/app/xcf/xcf-write.c b/app/xcf/xcf-write.c
index 83ea9b0..313c830 100644
--- a/app/xcf/xcf-write.c
+++ b/app/xcf/xcf-write.c
@@ -64,16 +64,26 @@ xcf_write_offset (XcfInfo        *info,
                   gint            count,
                   GError        **error)
 {
-  GError *tmp_error = NULL;
-  gint    i;
-
   if (count > 0)
     {
+      gint i;
+
       for (i = 0; i < count; i++)
         {
-          guint32 tmp = g_htonl (data[i]);
+          GError *tmp_error = NULL;
 
-          xcf_write_int8 (info, (const guint8 *) &tmp, 4, &tmp_error);
+          if (info->bytes_per_offset == 4)
+            {
+              guint32 tmp = g_htonl (data[i]);
+
+              xcf_write_int8 (info, (const guint8 *) &tmp, 4, &tmp_error);
+            }
+          else
+            {
+              gint64 tmp = GINT64_TO_BE (data[i]);
+
+              xcf_write_int8 (info, (const guint8 *) &tmp, 8, &tmp_error);
+            }
 
           if (tmp_error)
             {
@@ -94,11 +104,12 @@ xcf_write_zero_offset (XcfInfo  *info,
 {
   if (count > 0)
     {
-      guint32 *tmp = g_alloca (count * 4);
+      guint8 *tmp = g_alloca (count * info->bytes_per_offset);
 
-      memset (tmp, 0, count * 4);
+      memset (tmp, 0, count * info->bytes_per_offset);
 
-      return xcf_write_int8 (info, (const guint8 *) tmp, count * 4, error);
+      return xcf_write_int8 (info, (const guint8 *) tmp,
+                             count * info->bytes_per_offset, error);
     }
 
   return 0;