Bug 485559 – Boston Summit HarfBuzz optimizations
2007-10-10 Behdad Esfahbod <behdad@gnome.org>
Bug 485559 – Boston Summit HarfBuzz optimizations
* pango/opentype/*: HarfBuzz hacking to:
- Rename last remaining FT_Err stuff to HB_Err.
- Fix a couple invalid table paths to be permissive so
fonts work better. Particularly GDEF table for Nafees
Nastaliq is loaded and works great now.
- Optimize harfbuzz buffer to not copy/swap for simple
one-to-one and "copy" GSUB operations.
* pango/pango-ot*: Update to FT_Err to HB_Err renaming.
diff --git a/src/harfbuzz-buffer.c b/src/harfbuzz-buffer.c
index 40a7d2b..148d98d 100644
--- a/src/harfbuzz-buffer.c
+++ b/src/harfbuzz-buffer.c
@@ -1,6 +1,6 @@
/* harfbuzz-buffer.c: Buffer of glyphs for substitution/positioning
*
- * Copyright 2004 Red Hat Software
+ * Copyright 2004,2007 Red Hat Software
*
* Portions Copyright 1996-2000 by
* David Turner, Robert Wilhelm, and Werner Lemberg.
@@ -11,7 +11,34 @@
#include "harfbuzz-gsub-private.h"
#include "harfbuzz-gpos-private.h"
-static FT_Error
+/* Here is how the buffer works internally:
+ *
+ * There are two string pointers: in_string and out_string. They
+ * always have same allocated size, but different length and positions.
+ *
+ * As an optimization, both in_string and out_string may point to the
+ * same piece of memory, which is owned by in_string. This remains the
+ * case as long as:
+ *
+ * - copy_glyph() is called
+ * - replace_glyph() is called with inplace=TRUE
+ * - add_output_glyph() and add_output_glyphs() are not called
+ *
+ * In that case swap(), and copy_glyph(), and replace_glyph() are all
+ * mostly no-op.
+ *
+ * As soon an add_output_glyph[s]() or replace_glyph() with inplace=FALSE is
+ * called, out_string is moved over to an alternate buffer (alt_string), and
+ * its current contents (out_length entries) are copied to the alt buffer.
+ * This should all remain transparent to the user. swap() then switches
+ * in_string and alt_string. alt_string is not allocated until its needed,
+ * but after that it's grown with in_string unconditionally.
+ *
+ * The buffer->inplace boolean keeps status of whether out_string points to
+ * in_string or alt_string.
+ */
+
+static HB_Error
hb_buffer_ensure( HB_Buffer buffer,
FT_ULong size )
{
@@ -20,29 +47,63 @@
if (size > new_allocated)
{
- FT_Error error;
+ HB_Error error;
while (size > new_allocated)
new_allocated += (new_allocated >> 1) + 8;
- if ( REALLOC_ARRAY( buffer->in_string, buffer->allocated, new_allocated, HB_GlyphItemRec ) )
- return error;
- if ( REALLOC_ARRAY( buffer->out_string, buffer->allocated, new_allocated, HB_GlyphItemRec ) )
- return error;
if ( REALLOC_ARRAY( buffer->positions, buffer->allocated, new_allocated, HB_PositionRec ) )
return error;
+ if ( REALLOC_ARRAY( buffer->in_string, buffer->allocated, new_allocated, HB_GlyphItemRec ) )
+ return error;
+ if ( buffer->inplace )
+ {
+ buffer->out_string = buffer->in_string;
+
+ if ( buffer->alt_string )
+ {
+ if ( REALLOC_ARRAY( buffer->alt_string, buffer->allocated, new_allocated, HB_GlyphItemRec ) )
+ return error;
+ }
+ }
+ else
+ {
+ if ( REALLOC_ARRAY( buffer->alt_string, buffer->allocated, new_allocated, HB_GlyphItemRec ) )
+ return error;
+
+ buffer->out_string = buffer->alt_string;
+ }
buffer->allocated = new_allocated;
}
- return FT_Err_Ok;
+ return HB_Err_Ok;
}
-FT_Error
+static HB_Error
+hb_buffer_duplicate_out_buffer( HB_Buffer buffer )
+{
+ if ( !buffer->alt_string )
+ {
+ FT_Memory memory = buffer->memory;
+ HB_Error error;
+
+ if ( ALLOC_ARRAY( buffer->alt_string, buffer->allocated, HB_GlyphItemRec ) )
+ return error;
+ }
+
+ buffer->out_string = buffer->alt_string;
+ memcpy( buffer->out_string, buffer->in_string, buffer->out_length * sizeof (buffer->out_string[0]) );
+ buffer->inplace = FALSE;
+
+ return HB_Err_Ok;
+}
+
+HB_Error
hb_buffer_new( FT_Memory memory,
HB_Buffer *buffer )
{
- FT_Error error;
+ HB_Error error;
if ( ALLOC( *buffer, sizeof( HB_BufferRec ) ) )
return error;
@@ -56,61 +117,77 @@
(*buffer)->in_string = NULL;
(*buffer)->out_string = NULL;
+ (*buffer)->alt_string = NULL;
(*buffer)->positions = NULL;
(*buffer)->max_ligID = 0;
+ (*buffer)->inplace = TRUE;
- return FT_Err_Ok;
+ return HB_Err_Ok;
}
-FT_Error
+void
+hb_buffer_clear_output( HB_Buffer buffer )
+{
+ buffer->out_length = 0;
+ buffer->out_pos = 0;
+ buffer->out_string = buffer->in_string;
+ buffer->inplace = TRUE;
+}
+
+void
hb_buffer_swap( HB_Buffer buffer )
{
HB_GlyphItem tmp_string;
+ int tmp_length;
+ int tmp_pos;
- tmp_string = buffer->in_string;
- buffer->in_string = buffer->out_string;
- buffer->out_string = tmp_string;
+ if ( ! buffer->inplace )
+ {
+ tmp_string = buffer->in_string;
+ buffer->in_string = buffer->out_string;
+ buffer->out_string = tmp_string;
+ buffer->alt_string = buffer->out_string;
+ }
+ tmp_length = buffer->in_length;
buffer->in_length = buffer->out_length;
- buffer->out_length = 0;
-
- buffer->in_pos = 0;
- buffer->out_pos = 0;
+ buffer->out_length = tmp_length;
- return FT_Err_Ok;
+ tmp_pos = buffer->in_pos;
+ buffer->in_pos = buffer->out_pos;
+ buffer->out_pos = tmp_pos;
}
-FT_Error
+void
hb_buffer_free( HB_Buffer buffer )
{
FT_Memory memory = buffer->memory;
FREE( buffer->in_string );
- FREE( buffer->out_string );
+ FREE( buffer->alt_string );
+ buffer->out_string = NULL;
FREE( buffer->positions );
FREE( buffer );
-
- return FT_Err_Ok;
}
-FT_Error
+void
hb_buffer_clear( HB_Buffer buffer )
{
buffer->in_length = 0;
buffer->out_length = 0;
buffer->in_pos = 0;
buffer->out_pos = 0;
-
- return FT_Err_Ok;
+ buffer->out_string = buffer->in_string;
+ buffer->inplace = TRUE;
}
-FT_Error
+HB_Error
hb_buffer_add_glyph( HB_Buffer buffer,
FT_UInt glyph_index,
FT_UInt properties,
FT_UInt cluster )
{
- FT_Error error;
+ HB_Error error;
HB_GlyphItem glyph;
error = hb_buffer_ensure( buffer, buffer->in_length + 1 );
@@ -127,7 +204,7 @@
buffer->in_length++;
- return FT_Err_Ok;
+ return HB_Err_Ok;
}
/* The following function copies `num_out' elements from `glyph_data'
@@ -149,7 +226,7 @@
The cluster value for the glyph at position buffer->in_pos is used
for all replacement glyphs */
-FT_Error
+HB_Error
hb_buffer_add_output_glyphs( HB_Buffer buffer,
FT_UShort num_in,
FT_UShort num_out,
@@ -157,7 +234,7 @@
FT_UShort component,
FT_UShort ligID )
{
- FT_Error error;
+ HB_Error error;
FT_UShort i;
FT_UInt properties;
FT_UInt cluster;
@@ -166,6 +243,13 @@
if ( error )
return error;
+ if ( buffer->inplace )
+ {
+ error = hb_buffer_duplicate_out_buffer( buffer );
+ if ( error )
+ return error;
+ }
+
properties = buffer->in_string[buffer->in_pos].properties;
cluster = buffer->in_string[buffer->in_pos].cluster;
if ( component == 0xFFFF )
@@ -190,10 +274,10 @@
buffer->out_length = buffer->out_pos;
- return FT_Err_Ok;
+ return HB_Err_Ok;
}
-FT_Error
+HB_Error
hb_buffer_add_output_glyph( HB_Buffer buffer,
FT_UInt glyph_index,
FT_UShort component,
@@ -205,19 +289,49 @@
&glyph_data, component, ligID );
}
-FT_Error
+HB_Error
hb_buffer_copy_output_glyph ( HB_Buffer buffer )
{
- FT_Error error;
+ HB_Error error;
error = hb_buffer_ensure( buffer, buffer->out_pos + 1 );
if ( error )
return error;
- buffer->out_string[buffer->out_pos++] = buffer->in_string[buffer->in_pos++];
+ if ( ! buffer->inplace )
+ {
+ buffer->out_string[buffer->out_pos] = buffer->in_string[buffer->in_pos];
+ }
+
+ buffer->in_pos++;
+ buffer->out_pos++;
buffer->out_length = buffer->out_pos;
- return FT_Err_Ok;
+ return HB_Err_Ok;
+}
+
+HB_Error
+hb_buffer_replace_output_glyph( HB_Buffer buffer,
+ FT_UInt glyph_index,
+ FT_Bool inplace )
+{
+
+ HB_Error error;
+
+ if ( inplace )
+ {
+ error = hb_buffer_copy_output_glyph ( buffer );
+ if ( error )
+ return error;
+
+ buffer->out_string[buffer->out_pos-1].gindex = glyph_index;
+ }
+ else
+ {
+ return hb_buffer_add_output_glyph( buffer, glyph_index, 0xFFFF, 0xFFFF );
+ }
+
+ return HB_Err_Ok;
}
FT_UShort
