From 36d22d82aa202bb199967e9512281e9a53db42c9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 21:33:14 +0200 Subject: Adding upstream version 115.7.0esr. Signed-off-by: Daniel Baumann --- modules/freetype2/src/sfnt/ttkern.c | 317 ++++++++++++++++++++++++++++++++++++ 1 file changed, 317 insertions(+) create mode 100644 modules/freetype2/src/sfnt/ttkern.c (limited to 'modules/freetype2/src/sfnt/ttkern.c') diff --git a/modules/freetype2/src/sfnt/ttkern.c b/modules/freetype2/src/sfnt/ttkern.c new file mode 100644 index 0000000000..a47d08bd6d --- /dev/null +++ b/modules/freetype2/src/sfnt/ttkern.c @@ -0,0 +1,317 @@ +/**************************************************************************** + * + * ttkern.c + * + * Load the basic TrueType kerning table. This doesn't handle + * kerning data within the GPOS table at the moment. + * + * Copyright (C) 1996-2023 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 +#include +#include +#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 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 = FT_THROW( 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, format; + 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 + 8 ) + break; + + p_next += length; + + if ( p_next > p_limit ) /* handle broken table */ + p_next = p_limit; + + format = coverage >> 8; + + /* we currently only support format 0 kerning tables */ + if ( format != 0 ) + goto NextTable; + + /* only use horizontal kerning tables */ + if ( ( coverage & 3U ) != 0x0001 || + p + 8 > p_next ) + 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; + + FT_Byte* p; + FT_Byte* p_limit; + + + if ( !face->kern_table ) + return result; + + p = face->kern_table; + 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; + 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; + + FT_ASSERT( p + 8 <= next ); /* tested in tt_face_load_kern */ + + 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 */ -- cgit v1.2.3