--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/misc/libfreetype/src/sfnt/ttkern.c Mon Apr 25 01:46:54 2011 +0200
@@ -0,0 +1,306 @@
+/***************************************************************************/
+/* */
+/* ttkern.c */
+/* */
+/* Load the basic TrueType kerning table. This doesn't handle */
+/* kerning data within the GPOS table at the moment. */
+/* */
+/* Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010 by */
+/* David Turner, Robert Wilhelm, and Werner Lemberg. */
+/* */
+/* This file is part of the FreeType project, and may only be used, */
+/* modified, and distributed under the terms of the FreeType project */
+/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
+/* this file you indicate that you have read the license and */
+/* understand and accept it fully. */
+/* */
+/***************************************************************************/
+
+
+#include <ft2build.h>
+#include FT_INTERNAL_DEBUG_H
+#include FT_INTERNAL_STREAM_H
+#include FT_TRUETYPE_TAGS_H
+#include "ttkern.h"
+
+#include "sferrors.h"
+
+
+ /*************************************************************************/
+ /* */
+ /* The macro FT_COMPONENT is used in trace mode. It is an implicit */
+ /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */
+ /* messages during execution. */
+ /* */
+#undef FT_COMPONENT
+#define FT_COMPONENT trace_ttkern
+
+
+#undef TT_KERN_INDEX
+#define TT_KERN_INDEX( g1, g2 ) ( ( (FT_ULong)(g1) << 16 ) | (g2) )
+
+
+ FT_LOCAL_DEF( FT_Error )
+ tt_face_load_kern( TT_Face face,
+ FT_Stream stream )
+ {
+ FT_Error error;
+ FT_ULong table_size;
+ FT_Byte* p;
+ FT_Byte* p_limit;
+ FT_UInt nn, num_tables;
+ FT_UInt32 avail = 0, ordered = 0;
+
+
+ /* the kern table is optional; exit silently if it is missing */
+ error = face->goto_table( face, TTAG_kern, stream, &table_size );
+ if ( error )
+ goto Exit;
+
+ if ( table_size < 4 ) /* the case of a malformed table */
+ {
+ FT_ERROR(( "tt_face_load_kern:"
+ " kerning table is too small - ignored\n" ));
+ error = SFNT_Err_Table_Missing;
+ goto Exit;
+ }
+
+ if ( FT_FRAME_EXTRACT( table_size, face->kern_table ) )
+ {
+ FT_ERROR(( "tt_face_load_kern:"
+ " could not extract kerning table\n" ));
+ goto Exit;
+ }
+
+ face->kern_table_size = table_size;
+
+ p = face->kern_table;
+ p_limit = p + table_size;
+
+ p += 2; /* skip version */
+ num_tables = FT_NEXT_USHORT( p );
+
+ if ( num_tables > 32 ) /* we only support up to 32 sub-tables */
+ num_tables = 32;
+
+ for ( nn = 0; nn < num_tables; nn++ )
+ {
+ FT_UInt num_pairs, length, coverage;
+ FT_Byte* p_next;
+ FT_UInt32 mask = (FT_UInt32)1UL << nn;
+
+
+ if ( p + 6 > p_limit )
+ break;
+
+ p_next = p;
+
+ p += 2; /* skip version */
+ length = FT_NEXT_USHORT( p );
+ coverage = FT_NEXT_USHORT( p );
+
+ if ( length <= 6 )
+ break;
+
+ p_next += length;
+
+ if ( p_next > p_limit ) /* handle broken table */
+ p_next = p_limit;
+
+ /* only use horizontal kerning tables */
+ if ( ( coverage & ~8 ) != 0x0001 ||
+ p + 8 > p_limit )
+ goto NextTable;
+
+ num_pairs = FT_NEXT_USHORT( p );
+ p += 6;
+
+ if ( ( p_next - p ) < 6 * (int)num_pairs ) /* handle broken count */
+ num_pairs = (FT_UInt)( ( p_next - p ) / 6 );
+
+ avail |= mask;
+
+ /*
+ * Now check whether the pairs in this table are ordered.
+ * We then can use binary search.
+ */
+ if ( num_pairs > 0 )
+ {
+ FT_ULong count;
+ FT_ULong old_pair;
+
+
+ old_pair = FT_NEXT_ULONG( p );
+ p += 2;
+
+ for ( count = num_pairs - 1; count > 0; count-- )
+ {
+ FT_UInt32 cur_pair;
+
+
+ cur_pair = FT_NEXT_ULONG( p );
+ if ( cur_pair <= old_pair )
+ break;
+
+ p += 2;
+ old_pair = cur_pair;
+ }
+
+ if ( count == 0 )
+ ordered |= mask;
+ }
+
+ NextTable:
+ p = p_next;
+ }
+
+ face->num_kern_tables = nn;
+ face->kern_avail_bits = avail;
+ face->kern_order_bits = ordered;
+
+ Exit:
+ return error;
+ }
+
+
+ FT_LOCAL_DEF( void )
+ tt_face_done_kern( TT_Face face )
+ {
+ FT_Stream stream = face->root.stream;
+
+
+ FT_FRAME_RELEASE( face->kern_table );
+ face->kern_table_size = 0;
+ face->num_kern_tables = 0;
+ face->kern_avail_bits = 0;
+ face->kern_order_bits = 0;
+ }
+
+
+ FT_LOCAL_DEF( FT_Int )
+ tt_face_get_kerning( TT_Face face,
+ FT_UInt left_glyph,
+ FT_UInt right_glyph )
+ {
+ FT_Int result = 0;
+ FT_UInt count, mask = 1;
+ FT_Byte* p = face->kern_table;
+ FT_Byte* p_limit = p + face->kern_table_size;
+
+
+ p += 4;
+ mask = 0x0001;
+
+ for ( count = face->num_kern_tables;
+ count > 0 && p + 6 <= p_limit;
+ count--, mask <<= 1 )
+ {
+ FT_Byte* base = p;
+ FT_Byte* next = base;
+ FT_UInt version = FT_NEXT_USHORT( p );
+ FT_UInt length = FT_NEXT_USHORT( p );
+ FT_UInt coverage = FT_NEXT_USHORT( p );
+ FT_UInt num_pairs;
+ FT_Int value = 0;
+
+ FT_UNUSED( version );
+
+
+ next = base + length;
+
+ if ( next > p_limit ) /* handle broken table */
+ next = p_limit;
+
+ if ( ( face->kern_avail_bits & mask ) == 0 )
+ goto NextTable;
+
+ if ( p + 8 > next )
+ goto NextTable;
+
+ num_pairs = FT_NEXT_USHORT( p );
+ p += 6;
+
+ if ( ( next - p ) < 6 * (int)num_pairs ) /* handle broken count */
+ num_pairs = (FT_UInt)( ( next - p ) / 6 );
+
+ switch ( coverage >> 8 )
+ {
+ case 0:
+ {
+ FT_ULong key0 = TT_KERN_INDEX( left_glyph, right_glyph );
+
+
+ if ( face->kern_order_bits & mask ) /* binary search */
+ {
+ FT_UInt min = 0;
+ FT_UInt max = num_pairs;
+
+
+ while ( min < max )
+ {
+ FT_UInt mid = ( min + max ) >> 1;
+ FT_Byte* q = p + 6 * mid;
+ FT_ULong key;
+
+
+ key = FT_NEXT_ULONG( q );
+
+ if ( key == key0 )
+ {
+ value = FT_PEEK_SHORT( q );
+ goto Found;
+ }
+ if ( key < key0 )
+ min = mid + 1;
+ else
+ max = mid;
+ }
+ }
+ else /* linear search */
+ {
+ FT_UInt count2;
+
+
+ for ( count2 = num_pairs; count2 > 0; count2-- )
+ {
+ FT_ULong key = FT_NEXT_ULONG( p );
+
+
+ if ( key == key0 )
+ {
+ value = FT_PEEK_SHORT( p );
+ goto Found;
+ }
+ p += 2;
+ }
+ }
+ }
+ break;
+
+ /*
+ * We don't support format 2 because we haven't seen a single font
+ * using it in real life...
+ */
+
+ default:
+ ;
+ }
+
+ goto NextTable;
+
+ Found:
+ if ( coverage & 8 ) /* override or add */
+ result = value;
+ else
+ result += value;
+
+ NextTable:
+ p = next;
+ }
+
+ return result;
+ }
+
+#undef TT_KERN_INDEX
+
+/* END */