Edit
kc3-lang/freetype/src/sfnt/ttsvg.c
Werner Lemberg
- src/sfnt/ttsvg.c
-
/**************************************************************************** * * ttsvg.c * * OpenType SVG Color (specification). * * Copyright (C) 2022-2024 by * David Turner, Robert Wilhelm, Werner Lemberg, and Moazin Khatti. * * 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. * */ /************************************************************************** * * 'SVG' table specification: * * https://learn.microsoft.com/typography/opentype/spec/svg * */ #include <ft2build.h> #include <freetype/internal/ftstream.h> #include <freetype/internal/ftobjs.h> #include <freetype/internal/ftdebug.h> #include <freetype/tttags.h> #include <freetype/ftgzip.h> #include <freetype/otsvg.h> #ifdef FT_CONFIG_OPTION_SVG #include "ttsvg.h" /* NOTE: These table sizes are given by the specification. */ #define SVG_TABLE_HEADER_SIZE (10U) #define SVG_DOCUMENT_RECORD_SIZE (12U) #define SVG_DOCUMENT_LIST_MINIMUM_SIZE (2U + SVG_DOCUMENT_RECORD_SIZE) #define SVG_MINIMUM_SIZE (SVG_TABLE_HEADER_SIZE + \ SVG_DOCUMENT_LIST_MINIMUM_SIZE) /* An arbitrary, heuristic size limit (67MByte) for expanded SVG data. */ #define MAX_SVG_SIZE ( 1 << 26 ) typedef struct Svg_ { FT_UShort version; /* table version (starting at 0) */ FT_UShort num_entries; /* number of SVG document records */ FT_Byte* svg_doc_list; /* pointer to the start of SVG Document List */ void* table; /* memory that backs up SVG */ FT_ULong table_size; } Svg; /************************************************************************** * * The macro FT_COMPONENT is used in trace mode. It is an implicit * parameter of the FT_TRACE() and FT_ERROR() macros, usued to print/log * messages during execution. */ #undef FT_COMPONENT #define FT_COMPONENT ttsvg FT_LOCAL_DEF( FT_Error ) tt_face_load_svg( TT_Face face, FT_Stream stream ) { FT_Error error; FT_Memory memory = face->root.memory; FT_ULong table_size; FT_Byte* table = NULL; FT_Byte* p = NULL; Svg* svg = NULL; FT_ULong offsetToSVGDocumentList; error = face->goto_table( face, TTAG_SVG, stream, &table_size ); if ( error ) goto NoSVG; if ( table_size < SVG_MINIMUM_SIZE ) goto InvalidTable; if ( FT_FRAME_EXTRACT( table_size, table ) ) goto NoSVG; /* Allocate memory for the SVG object */ if ( FT_NEW( svg ) ) goto NoSVG; p = table; svg->version = FT_NEXT_USHORT( p ); offsetToSVGDocumentList = FT_NEXT_ULONG( p ); if ( offsetToSVGDocumentList < SVG_TABLE_HEADER_SIZE || offsetToSVGDocumentList > table_size - SVG_DOCUMENT_LIST_MINIMUM_SIZE ) goto InvalidTable; svg->svg_doc_list = (FT_Byte*)( table + offsetToSVGDocumentList ); p = svg->svg_doc_list; svg->num_entries = FT_NEXT_USHORT( p ); FT_TRACE3(( "version: %d\n", svg->version )); FT_TRACE3(( "number of entries: %d\n", svg->num_entries )); if ( offsetToSVGDocumentList + 2U + svg->num_entries * SVG_DOCUMENT_RECORD_SIZE > table_size ) goto InvalidTable; svg->table = table; svg->table_size = table_size; face->svg = svg; face->root.face_flags |= FT_FACE_FLAG_SVG; return FT_Err_Ok; InvalidTable: error = FT_THROW( Invalid_Table ); NoSVG: FT_FRAME_RELEASE( table ); FT_FREE( svg ); face->svg = NULL; return error; } FT_LOCAL_DEF( void ) tt_face_free_svg( TT_Face face ) { FT_Memory memory = face->root.memory; FT_Stream stream = face->root.stream; Svg* svg = (Svg*)face->svg; if ( svg ) { FT_FRAME_RELEASE( svg->table ); FT_FREE( svg ); } } typedef struct Svg_doc_ { FT_UShort start_glyph_id; FT_UShort end_glyph_id; FT_ULong offset; FT_ULong length; } Svg_doc; static Svg_doc extract_svg_doc( FT_Byte* stream ) { Svg_doc doc; doc.start_glyph_id = FT_NEXT_USHORT( stream ); doc.end_glyph_id = FT_NEXT_USHORT( stream ); doc.offset = FT_NEXT_ULONG( stream ); doc.length = FT_NEXT_ULONG( stream ); return doc; } static FT_Int compare_svg_doc( Svg_doc doc, FT_UInt glyph_index ) { if ( glyph_index < doc.start_glyph_id ) return -1; else if ( glyph_index > doc.end_glyph_id ) return 1; else return 0; } static FT_Error find_doc( FT_Byte* document_records, FT_UShort num_entries, FT_UInt glyph_index, FT_ULong *doc_offset, FT_ULong *doc_length, FT_UShort *start_glyph, FT_UShort *end_glyph ) { FT_Error error; Svg_doc start_doc; Svg_doc mid_doc = { 0, 0, 0, 0 }; /* pacify compiler */ Svg_doc end_doc; FT_Bool found = FALSE; FT_UInt i = 0; FT_UInt start_index = 0; FT_UInt end_index = num_entries - 1; FT_Int comp_res; /* search algorithm */ if ( num_entries == 0 ) { error = FT_THROW( Invalid_Table ); return error; } start_doc = extract_svg_doc( document_records + start_index * 12 ); end_doc = extract_svg_doc( document_records + end_index * 12 ); if ( ( compare_svg_doc( start_doc, glyph_index ) == -1 ) || ( compare_svg_doc( end_doc, glyph_index ) == 1 ) ) { error = FT_THROW( Invalid_Glyph_Index ); return error; } while ( start_index <= end_index ) { i = ( start_index + end_index ) / 2; mid_doc = extract_svg_doc( document_records + i * 12 ); comp_res = compare_svg_doc( mid_doc, glyph_index ); if ( comp_res == 1 ) { start_index = i + 1; start_doc = extract_svg_doc( document_records + start_index * 4 ); } else if ( comp_res == -1 ) { end_index = i - 1; end_doc = extract_svg_doc( document_records + end_index * 4 ); } else { found = TRUE; break; } } /* search algorithm end */ if ( found != TRUE ) { FT_TRACE5(( "SVG glyph not found\n" )); error = FT_THROW( Invalid_Glyph_Index ); } else { *doc_offset = mid_doc.offset; *doc_length = mid_doc.length; *start_glyph = mid_doc.start_glyph_id; *end_glyph = mid_doc.end_glyph_id; error = FT_Err_Ok; } return error; } FT_LOCAL_DEF( FT_Error ) tt_face_load_svg_doc( FT_GlyphSlot glyph, FT_UInt glyph_index ) { FT_Error error = FT_Err_Ok; TT_Face face = (TT_Face)glyph->face; FT_Memory memory = face->root.memory; Svg* svg = (Svg*)face->svg; FT_Byte* doc_list; FT_ULong doc_limit; FT_Byte* doc; FT_ULong doc_offset; FT_ULong doc_length; FT_UShort doc_start_glyph_id; FT_UShort doc_end_glyph_id; FT_SVG_Document svg_document = (FT_SVG_Document)glyph->other; FT_ASSERT( !( svg == NULL ) ); doc_list = svg->svg_doc_list; error = find_doc( doc_list + 2, svg->num_entries, glyph_index, &doc_offset, &doc_length, &doc_start_glyph_id, &doc_end_glyph_id ); if ( error != FT_Err_Ok ) goto Exit; doc_limit = svg->table_size - (FT_ULong)( doc_list - (FT_Byte*)svg->table ); if ( doc_offset > doc_limit || doc_length > doc_limit - doc_offset ) { error = FT_THROW( Invalid_Table ); goto Exit; } doc = doc_list + doc_offset; if ( doc_length > 6 && doc[0] == 0x1F && doc[1] == 0x8B && doc[2] == 0x08 ) { #ifdef FT_CONFIG_OPTION_USE_ZLIB FT_ULong uncomp_size; FT_Byte* uncomp_buffer = NULL; /* * Get the size of the original document. This helps in allotting the * buffer to accommodate the uncompressed version. The last 4 bytes * of the compressed document are equal to the original size modulo * 2^32. Since the size of SVG documents is less than 2^32 bytes we * can use this accurately. The four bytes are stored in * little-endian format. */ FT_TRACE4(( "SVG document is GZIP compressed\n" )); uncomp_size = (FT_ULong)doc[doc_length - 1] << 24 | (FT_ULong)doc[doc_length - 2] << 16 | (FT_ULong)doc[doc_length - 3] << 8 | (FT_ULong)doc[doc_length - 4]; if ( uncomp_size >= MAX_SVG_SIZE ) { FT_ERROR(( "Uncompressed SVG document too large.\n" )); error = FT_THROW( Array_Too_Large ); goto Exit; } if ( FT_QALLOC( uncomp_buffer, uncomp_size ) ) goto Exit; error = FT_Gzip_Uncompress( memory, uncomp_buffer, &uncomp_size, doc, doc_length ); if ( error ) { FT_FREE( uncomp_buffer ); error = FT_THROW( Invalid_Table ); goto Exit; } glyph->internal->flags |= FT_GLYPH_OWN_GZIP_SVG; doc = uncomp_buffer; doc_length = uncomp_size; #else /* !FT_CONFIG_OPTION_USE_ZLIB */ error = FT_THROW( Unimplemented_Feature ); goto Exit; #endif /* !FT_CONFIG_OPTION_USE_ZLIB */ } svg_document->svg_document = doc; svg_document->svg_document_length = doc_length; svg_document->metrics = glyph->face->size->metrics; svg_document->units_per_EM = glyph->face->units_per_EM; svg_document->start_glyph_id = doc_start_glyph_id; svg_document->end_glyph_id = doc_end_glyph_id; svg_document->transform.xx = 0x10000; svg_document->transform.xy = 0; svg_document->transform.yx = 0; svg_document->transform.yy = 0x10000; svg_document->delta.x = 0; svg_document->delta.y = 0; FT_TRACE5(( "start_glyph_id: %d\n", doc_start_glyph_id )); FT_TRACE5(( "end_glyph_id: %d\n", doc_end_glyph_id )); FT_TRACE5(( "svg_document:\n" )); FT_TRACE5(( " %.*s\n", (FT_UInt)doc_length, doc )); glyph->other = svg_document; Exit: return error; } #else /* !FT_CONFIG_OPTION_SVG */ /* ANSI C doesn't like empty source files */ typedef int tt_svg_dummy_; #endif /* !FT_CONFIG_OPTION_SVG */ /* END */