Fix (pdfwrite) : Generate pseudo-random font names for subset fonts

from the glyph usage array.
Bug 686807 A "subset fonts" error in Adobe Acrobat from files made by GS8.00

DETAILS :

Since the revision 1.9 of gdevpdtb.c (Sun Sep 8 20:20:12 2002 UTC)
subset font names were deterministic to simplify the debugging.
The names were derived from resource IDs, and could cause a conflict
when merging documents. This patch generates different font names
hashing the glyph usage bitmask. Now the conflict can happen
with a very small probablility, when different subsets give same
hash value.

git-svn-id: http://svn.ghostscript.com/ghostscript/trunk@3813 a1074d23-0009-0410-80fe-cf8c14f379e6

1 files changed, 17 insertions, 3 deletions

diff --git a/gs/src/gdevpdtb.h b/gs/src/gdevpdtb.h
index b6d89023b..545715322 100644
--- a/gs/src/gdevpdtb.h
+++ b/gs/src/gdevpdtb.h
@@ -90,6 +90,11 @@ gs_string *pdf_base_font_name(pdf_base_font_t *pbfont);
 gs_font_base *pdf_base_font_font(const pdf_base_font_t *pbfont, bool complete);
 
 /*
+ * Check for subset font.
+ */
+bool pdf_base_font_is_subset(const pdf_base_font_t *pbfont);
+
+/*
  * Drop the copied complete font associated with a base font.
  */
 void pdf_base_font_drop_complete(pdf_base_font_t *pbfont);
@@ -104,9 +109,18 @@ int pdf_base_font_copy_glyph(pdf_base_font_t *pbfont, gs_glyph glyph,
 			     gs_font_base *font);
 
 /*
- * Determine whether a copied font should be subsetted.  Note that if the
- * font is subsetted, this procedure modifies the copied font by adding the
- * XXXXXX+ font name prefix and clearing the UID.
+ * Determine whether a font is a subset font by examining the name.
+ */
+bool pdf_has_subset_prefix(const byte *str, uint size);
+
+/*
+ * Add the XXXXXX+ prefix for a subset font.
+ */
+int pdf_add_subset_prefix(const gx_device_pdf *pdev, gs_string *pstr, 
+			byte *used, int count);
+
+/*
+ * Determine whether a copied font should be subsetted.
  */
 bool pdf_do_subset_font(gx_device_pdf *pdev, pdf_base_font_t *pbfont, 
 			gs_id rid);