Fixes bug #320666:

2005-11-07  Federico Mena Quintero  <federico@ximian.com>

	Fixes bug #320666:

	Instead of doing a bsearch() for every gunichar to map it to a
	PangoScript, use a precomputed table for the first 8192 code
	points.  Also, remember the last script that we computed on each
	invocation; this will also help CJK and the other scripts above
	U+2000.

	This table also holds information on whether the characters in it
	are paired characters.  We can use this to avoid doing the
	expensive get_pair_index() call most of the time.

	Many thanks to Matthias Clasen for his suggestions for this patch.

	* tools/gen-easy-scripts-table.c: New program to generate
	pango_easy_scripts_table.

	* tools/Makefile.am: Build gen-easy-scripts-table.

	* pango/pango-easy-scripts-table.h: New file with a mapping of the
	first 8192 Unicode characters to their corresponding scripts.  The
	table also says whether each character has a paired char or not.

	* pango/Makefile.am (libpango_1_0_la_SOURCES): Add pango-easy-scripts-table.h.

	* pango/pango-script-table.h: Remove everything below U+2000, and
	add a note to that effect.

	* pango/pango-script.c (pango_script_for_unichar_with_last_index):
	New function.  This is the old pango_script_for_unichar(), but it
	lets the caller keep around the computed index in
	pango_script_table.  This works under the assumption that a
	character is likely to be in the same script block as the
	preceding character in a string.
	(pango_script_for_unichar): First, do a quick check against the
	pango_easy_scripts_table.  Then, do the expensive check with
	pango_script_for_unichar_with_last_index().
	(pango_script_iter_next): If the character is within the easy
	script range, find out if it is a paired character by using
	PANGO_PAIRED_CHAR_FLAG.
	(struct _PangoScriptIter): Add a last_index_for_script_lookup
	field.  We use this to maintain the last-lookup index from
	pango_script_for_unichar_with_last_index().
	(pango_script_iter_next): If the character is not within the easy
	script range, use pango_script_for_unichar_with_last_index(), and
	store the index in the last_index_for_script_lookup field of the
	PangoScriptIter.

1 files changed, 4 insertions, 1 deletions

diff --git a/tools/Makefile.am b/tools/Makefile.am
index d521c58b..9e7f2387 100644
--- a/tools/Makefile.am
+++ b/tools/Makefile.am
@@ -7,7 +7,7 @@ INCLUDES =					\
 	-DPANGO_DISABLE_DEPRECATED		\
 	$(PANGO_DEBUG_FLAGS)
 
-noinst_PROGRAMS = gen-script-for-lang
+noinst_PROGRAMS = gen-script-for-lang gen-easy-scripts-table
 
 EXTRA_DIST= 			\
 	add-copyright 		\
@@ -19,3 +19,6 @@ EXTRA_DIST= 			\
 
 gen_script_for_lang_SOURCES = gen-script-for-lang.c
 gen_script_for_lang_LDADD = ../pango/libpango-$(PANGO_API_VERSION).la
+
+gen_easy_scripts_table_SOURCES = gen-easy-scripts-table.c
+gen_easy_scripts_table_LDADD = ../pango/libpango-$(PANGO_API_VERSION).la