| // Copyright (c) 2011 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "gpos.h" |
| |
| #include <limits> |
| #include <vector> |
| |
| #include "gdef.h" |
| #include "gsub.h" |
| #include "layout.h" |
| #include "maxp.h" |
| |
| // GPOS - The Glyph Positioning Table |
| // http://www.microsoft.com/typography/otspec/gpos.htm |
| |
| namespace { |
| |
| enum GPOS_TYPE { |
| GPOS_TYPE_SINGLE_ADJUSTMENT = 1, |
| GPOS_TYPE_PAIR_ADJUSTMENT = 2, |
| GPOS_TYPE_CURSIVE_ATTACHMENT = 3, |
| GPOS_TYPE_MARK_TO_BASE_ATTACHMENT = 4, |
| GPOS_TYPE_MARK_TO_LIGATURE_ATTACHMENT = 5, |
| GPOS_TYPE_MARK_TO_MARK_ATTACHMENT = 6, |
| GPOS_TYPE_CONTEXT_POSITIONING = 7, |
| GPOS_TYPE_CHAINED_CONTEXT_POSITIONING = 8, |
| GPOS_TYPE_EXTENSION_POSITIONING = 9, |
| GPOS_TYPE_RESERVED = 10 |
| }; |
| |
| // The size of gpos header. |
| const unsigned kGposHeaderSize = 10; |
| // The maximum format number for anchor tables. |
| const uint16_t kMaxAnchorFormat = 3; |
| // The maximum number of class value. |
| const uint16_t kMaxClassDefValue = 0xFFFF; |
| |
| // Lookup type parsers. |
| bool ParseSingleAdjustment(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length); |
| bool ParsePairAdjustment(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length); |
| bool ParseCursiveAttachment(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length); |
| bool ParseMarkToBaseAttachment(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length); |
| bool ParseMarkToLigatureAttachment(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length); |
| bool ParseMarkToMarkAttachment(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length); |
| bool ParseContextPositioning(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length); |
| bool ParseChainedContextPositioning(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length); |
| bool ParseExtensionPositioning(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length); |
| |
| const ots::LookupSubtableParser::TypeParser kGposTypeParsers[] = { |
| {GPOS_TYPE_SINGLE_ADJUSTMENT, ParseSingleAdjustment}, |
| {GPOS_TYPE_PAIR_ADJUSTMENT, ParsePairAdjustment}, |
| {GPOS_TYPE_CURSIVE_ATTACHMENT, ParseCursiveAttachment}, |
| {GPOS_TYPE_MARK_TO_BASE_ATTACHMENT, ParseMarkToBaseAttachment}, |
| {GPOS_TYPE_MARK_TO_LIGATURE_ATTACHMENT, ParseMarkToLigatureAttachment}, |
| {GPOS_TYPE_MARK_TO_MARK_ATTACHMENT, ParseMarkToMarkAttachment}, |
| {GPOS_TYPE_CONTEXT_POSITIONING, ParseContextPositioning}, |
| {GPOS_TYPE_CHAINED_CONTEXT_POSITIONING, ParseChainedContextPositioning}, |
| {GPOS_TYPE_EXTENSION_POSITIONING, ParseExtensionPositioning} |
| }; |
| |
| const ots::LookupSubtableParser kGposLookupSubtableParser = { |
| arraysize(kGposTypeParsers), |
| GPOS_TYPE_EXTENSION_POSITIONING, kGposTypeParsers |
| }; |
| |
| // Shared Tables: ValueRecord, Anchor Table, and MarkArray |
| |
| bool ParseValueRecord(ots::Buffer* subtable, const uint8_t *data, |
| const size_t length, const uint16_t value_format) { |
| // Check existence of adjustment fields. |
| for (unsigned i = 0; i < 4; ++i) { |
| if ((value_format >> i) & 0x1) { |
| // Just read the field since these fileds could take an arbitrary values. |
| if (!subtable->Skip(2)) { |
| return OTS_FAILURE(); |
| } |
| } |
| } |
| |
| // Check existence of offsets to device table. |
| for (unsigned i = 0; i < 4; ++i) { |
| if ((value_format >> (i + 4)) & 0x1) { |
| uint16_t offset = 0; |
| if (!subtable->ReadU16(&offset)) { |
| return OTS_FAILURE(); |
| } |
| if (offset) { |
| // TODO(bashi): Is it possible that device tables locate before |
| // this record? No fonts contain such offset AKAIF. |
| if (offset >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ots::ParseDeviceTable(data + offset, length - offset)) { |
| return OTS_FAILURE(); |
| } |
| } |
| } |
| } |
| return true; |
| } |
| |
| bool ParseAnchorTable(const uint8_t *data, const size_t length) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t format = 0; |
| // Read format and skip 2 2-byte fields that could be arbitrary values. |
| if (!subtable.ReadU16(&format) || |
| !subtable.Skip(4)) { |
| return OTS_FAILURE(); |
| } |
| |
| if (format == 0 || format > kMaxAnchorFormat) { |
| return OTS_FAILURE(); |
| } |
| |
| // Format 2 and 3 has additional fields. |
| if (format == 2) { |
| // Format 2 provides an index to a glyph contour point, which will take |
| // arbitrary value. |
| uint16_t anchor_point = 0; |
| if (!subtable.ReadU16(&anchor_point)) { |
| return OTS_FAILURE(); |
| } |
| } else if (format == 3) { |
| uint16_t offset_x_device = 0; |
| uint16_t offset_y_device = 0; |
| if (!subtable.ReadU16(&offset_x_device) || |
| !subtable.ReadU16(&offset_y_device)) { |
| return OTS_FAILURE(); |
| } |
| const unsigned format_end = static_cast<unsigned>(10); |
| if (offset_x_device) { |
| if (offset_x_device < format_end || offset_x_device >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ots::ParseDeviceTable(data + offset_x_device, |
| length - offset_x_device)) { |
| return OTS_FAILURE(); |
| } |
| } |
| if (offset_y_device) { |
| if (offset_y_device < format_end || offset_y_device >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ots::ParseDeviceTable(data + offset_y_device, |
| length - offset_y_device)) { |
| return OTS_FAILURE(); |
| } |
| } |
| } |
| return true; |
| } |
| |
| bool ParseMarkArrayTable(const uint8_t *data, const size_t length, |
| const uint16_t class_count) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t mark_count = 0; |
| if (!subtable.ReadU16(&mark_count)) { |
| return OTS_FAILURE(); |
| } |
| |
| // MarkRecord consists of 4-bytes. |
| const unsigned mark_records_end = 4 * static_cast<unsigned>(mark_count) + 2; |
| if (mark_records_end > std::numeric_limits<uint16_t>::max()) { |
| return OTS_FAILURE(); |
| } |
| for (unsigned i = 0; i < mark_count; ++i) { |
| uint16_t class_value = 0; |
| uint16_t offset_mark_anchor = 0; |
| if (!subtable.ReadU16(&class_value) || |
| !subtable.ReadU16(&offset_mark_anchor)) { |
| return OTS_FAILURE(); |
| } |
| // |class_value| may take arbitrary values including 0 here so we don't |
| // check the value. |
| if (offset_mark_anchor < mark_records_end || |
| offset_mark_anchor >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ParseAnchorTable(data + offset_mark_anchor, |
| length - offset_mark_anchor)) { |
| return OTS_FAILURE(); |
| } |
| } |
| |
| return true; |
| } |
| |
| // Lookup Type 1: |
| // Single Adjustment Positioning Subtable |
| bool ParseSingleAdjustment(const ots::OpenTypeFile *file, const uint8_t *data, |
| const size_t length) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t format = 0; |
| uint16_t offset_coverage = 0; |
| uint16_t value_format = 0; |
| if (!subtable.ReadU16(&format) || |
| !subtable.ReadU16(&offset_coverage) || |
| !subtable.ReadU16(&value_format)) { |
| return OTS_FAILURE(); |
| } |
| |
| if (format == 1) { |
| // Format 1 exactly one value record. |
| if (!ParseValueRecord(&subtable, data, length, value_format)) { |
| return OTS_FAILURE(); |
| } |
| } else if (format == 2) { |
| uint16_t value_count = 0; |
| if (!subtable.ReadU16(&value_count)) { |
| return OTS_FAILURE(); |
| } |
| for (unsigned i = 0; i < value_count; ++i) { |
| if (!ParseValueRecord(&subtable, data, length, value_format)) { |
| return OTS_FAILURE(); |
| } |
| } |
| } else { |
| return OTS_FAILURE(); |
| } |
| |
| if (offset_coverage < subtable.offset() || offset_coverage >= length) { |
| return OTS_FAILURE(); |
| } |
| |
| if (!ots::ParseCoverageTable(data + offset_coverage, |
| length - offset_coverage, |
| file->maxp->num_glyphs)) { |
| return OTS_FAILURE(); |
| } |
| |
| return true; |
| } |
| |
| bool ParsePairSetTable(const uint8_t *data, const size_t length, |
| const uint16_t value_format1, |
| const uint16_t value_format2, |
| const uint16_t num_glyphs) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t value_count = 0; |
| if (!subtable.ReadU16(&value_count)) { |
| return OTS_FAILURE(); |
| } |
| for (unsigned i = 0; i < value_count; ++i) { |
| // Check pair value record. |
| uint16_t glyph_id = 0; |
| if (!subtable.ReadU16(&glyph_id)) { |
| return OTS_FAILURE(); |
| } |
| if (glyph_id >= num_glyphs) { |
| return OTS_FAILURE(); |
| } |
| if (!ParseValueRecord(&subtable, data, length, value_format1)) { |
| return OTS_FAILURE(); |
| } |
| if (!ParseValueRecord(&subtable, data, length, value_format2)) { |
| return OTS_FAILURE(); |
| } |
| } |
| return true; |
| } |
| |
| bool ParsePairPosFormat1(const uint8_t *data, const size_t length, |
| const uint16_t value_format1, |
| const uint16_t value_format2, |
| const uint16_t num_glyphs) { |
| ots::Buffer subtable(data, length); |
| |
| // Skip 8 bytes that are already read before. |
| if (!subtable.Skip(8)) { |
| return OTS_FAILURE(); |
| } |
| |
| uint16_t pair_set_count = 0; |
| if (!subtable.ReadU16(&pair_set_count)) { |
| return OTS_FAILURE(); |
| } |
| |
| const unsigned pair_pos_end = 2 * static_cast<unsigned>(pair_set_count) + 10; |
| if (pair_pos_end > std::numeric_limits<uint16_t>::max()) { |
| return OTS_FAILURE(); |
| } |
| for (unsigned i = 0; i < pair_set_count; ++i) { |
| uint16_t pair_set_offset = 0; |
| if (!subtable.ReadU16(&pair_set_offset)) { |
| return OTS_FAILURE(); |
| } |
| if (pair_set_offset < pair_pos_end || pair_set_offset >= length) { |
| return OTS_FAILURE(); |
| } |
| // Check pair set tables |
| if (!ParsePairSetTable(data + pair_set_offset, length - pair_set_offset, |
| value_format1, value_format2, |
| num_glyphs)) { |
| return OTS_FAILURE(); |
| } |
| } |
| |
| return true; |
| } |
| |
| bool ParsePairPosFormat2(const uint8_t *data, const size_t length, |
| const uint16_t value_format1, |
| const uint16_t value_format2, |
| const uint16_t num_glyphs) { |
| ots::Buffer subtable(data, length); |
| |
| // Skip 8 bytes that are already read before. |
| if (!subtable.Skip(8)) { |
| return OTS_FAILURE(); |
| } |
| |
| uint16_t offset_class_def1 = 0; |
| uint16_t offset_class_def2 = 0; |
| uint16_t class1_count = 0; |
| uint16_t class2_count = 0; |
| if (!subtable.ReadU16(&offset_class_def1) || |
| !subtable.ReadU16(&offset_class_def2) || |
| !subtable.ReadU16(&class1_count) || |
| !subtable.ReadU16(&class2_count)) { |
| return OTS_FAILURE(); |
| } |
| |
| // Check class 1 records. |
| for (unsigned i = 0; i < class1_count; ++i) { |
| // Check class 2 records. |
| for (unsigned j = 0; j < class2_count; ++j) { |
| if (value_format1 && !ParseValueRecord(&subtable, data, length, |
| value_format1)) { |
| return OTS_FAILURE(); |
| } |
| if (value_format2 && !ParseValueRecord(&subtable, data, length, |
| value_format2)) { |
| return OTS_FAILURE(); |
| } |
| } |
| } |
| |
| // Check class definition tables. |
| if (offset_class_def1 < subtable.offset() || offset_class_def1 >= length || |
| offset_class_def2 < subtable.offset() || offset_class_def2 >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ots::ParseClassDefTable(data + offset_class_def1, |
| length - offset_class_def1, |
| num_glyphs, kMaxClassDefValue)) { |
| return OTS_FAILURE(); |
| } |
| if (!ots::ParseClassDefTable(data + offset_class_def2, |
| length - offset_class_def2, |
| num_glyphs, kMaxClassDefValue)) { |
| return OTS_FAILURE(); |
| } |
| |
| return true; |
| } |
| |
| // Lookup Type 2: |
| // Pair Adjustment Positioning Subtable |
| bool ParsePairAdjustment(const ots::OpenTypeFile *file, const uint8_t *data, |
| const size_t length) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t format = 0; |
| uint16_t offset_coverage = 0; |
| uint16_t value_format1 = 0; |
| uint16_t value_format2 = 0; |
| if (!subtable.ReadU16(&format) || |
| !subtable.ReadU16(&offset_coverage) || |
| !subtable.ReadU16(&value_format1) || |
| !subtable.ReadU16(&value_format2)) { |
| return OTS_FAILURE(); |
| } |
| |
| if (format == 1) { |
| if (!ParsePairPosFormat1(data, length, value_format1, value_format2, |
| file->maxp->num_glyphs)) { |
| return OTS_FAILURE(); |
| } |
| } else if (format == 2) { |
| if (!ParsePairPosFormat2(data, length, value_format1, value_format2, |
| file->maxp->num_glyphs)) { |
| return OTS_FAILURE(); |
| } |
| } else { |
| return OTS_FAILURE(); |
| } |
| |
| if (offset_coverage < subtable.offset() || offset_coverage >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ots::ParseCoverageTable(data + offset_coverage, |
| length - offset_coverage, |
| file->maxp->num_glyphs)) { |
| return OTS_FAILURE(); |
| } |
| |
| return true; |
| } |
| |
| // Lookup Type 3 |
| // Cursive Attachment Positioning Subtable |
| bool ParseCursiveAttachment(const ots::OpenTypeFile *file, const uint8_t *data, |
| const size_t length) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t format = 0; |
| uint16_t offset_coverage = 0; |
| uint16_t entry_exit_count = 0; |
| if (!subtable.ReadU16(&format) || |
| !subtable.ReadU16(&offset_coverage) || |
| !subtable.ReadU16(&entry_exit_count)) { |
| return OTS_FAILURE(); |
| } |
| |
| if (format != 1) { |
| return OTS_FAILURE(); |
| } |
| |
| // Check entry exit records. |
| const unsigned entry_exit_records_end = |
| 2 * static_cast<unsigned>(entry_exit_count) + 6; |
| if (entry_exit_records_end > std::numeric_limits<uint16_t>::max()) { |
| return OTS_FAILURE(); |
| } |
| for (unsigned i = 0; i < entry_exit_count; ++i) { |
| uint16_t offset_entry_anchor = 0; |
| uint16_t offset_exit_anchor = 0; |
| if (!subtable.ReadU16(&offset_entry_anchor) || |
| !subtable.ReadU16(&offset_exit_anchor)) { |
| return OTS_FAILURE(); |
| } |
| // These offsets could be NULL. |
| if (offset_entry_anchor) { |
| if (offset_entry_anchor < entry_exit_records_end || |
| offset_entry_anchor >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ParseAnchorTable(data + offset_entry_anchor, |
| length - offset_entry_anchor)) { |
| return OTS_FAILURE(); |
| } |
| } |
| if (offset_exit_anchor) { |
| if (offset_exit_anchor < entry_exit_records_end || |
| offset_exit_anchor >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ParseAnchorTable(data + offset_exit_anchor, |
| length - offset_exit_anchor)) { |
| return OTS_FAILURE(); |
| } |
| } |
| } |
| |
| if (offset_coverage < subtable.offset() || offset_coverage >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ots::ParseCoverageTable(data + offset_coverage, |
| length - offset_coverage, |
| file->maxp->num_glyphs)) { |
| return OTS_FAILURE(); |
| } |
| |
| return true; |
| } |
| |
| bool ParseAnchorArrayTable(const uint8_t *data, const size_t length, |
| const uint16_t class_count) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t record_count = 0; |
| if (!subtable.ReadU16(&record_count)) { |
| return OTS_FAILURE(); |
| } |
| |
| const unsigned anchor_array_end = 2 * static_cast<unsigned>(record_count) * |
| static_cast<unsigned>(class_count) + 2; |
| if (anchor_array_end > std::numeric_limits<uint16_t>::max()) { |
| return OTS_FAILURE(); |
| } |
| for (unsigned i = 0; i < record_count; ++i) { |
| for (unsigned j = 0; j < class_count; ++j) { |
| uint16_t offset_record = 0; |
| if (!subtable.ReadU16(&offset_record)) { |
| return OTS_FAILURE(); |
| } |
| // |offset_record| could be NULL. |
| if (offset_record) { |
| if (offset_record < anchor_array_end || offset_record >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ParseAnchorTable(data + offset_record, |
| length - offset_record)) { |
| return OTS_FAILURE(); |
| } |
| } |
| } |
| } |
| return true; |
| } |
| |
| bool ParseLigatureArrayTable(const uint8_t *data, const size_t length, |
| const uint16_t class_count) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t ligature_count = 0; |
| if (!subtable.ReadU16(&ligature_count)) { |
| return OTS_FAILURE(); |
| } |
| for (unsigned i = 0; i < ligature_count; ++i) { |
| uint16_t offset_ligature_attach = 0; |
| if (!subtable.ReadU16(&offset_ligature_attach)) { |
| return OTS_FAILURE(); |
| } |
| if (offset_ligature_attach < 2 || offset_ligature_attach >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ParseAnchorArrayTable(data + offset_ligature_attach, |
| length - offset_ligature_attach, class_count)) { |
| return OTS_FAILURE(); |
| } |
| } |
| return true; |
| } |
| |
| // Common parser for Lookup Type 4, 5 and 6. |
| bool ParseMarkToAttachmentSubtables(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length, |
| const GPOS_TYPE type) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t format = 0; |
| uint16_t offset_coverage1 = 0; |
| uint16_t offset_coverage2 = 0; |
| uint16_t class_count = 0; |
| uint16_t offset_mark_array = 0; |
| uint16_t offset_type_specific_array = 0; |
| if (!subtable.ReadU16(&format) || |
| !subtable.ReadU16(&offset_coverage1) || |
| !subtable.ReadU16(&offset_coverage2) || |
| !subtable.ReadU16(&class_count) || |
| !subtable.ReadU16(&offset_mark_array) || |
| !subtable.ReadU16(&offset_type_specific_array)) { |
| return OTS_FAILURE(); |
| } |
| |
| if (format != 1) { |
| return OTS_FAILURE(); |
| } |
| |
| const unsigned header_end = static_cast<unsigned>(subtable.offset()); |
| if (header_end > std::numeric_limits<uint16_t>::max()) { |
| return OTS_FAILURE(); |
| } |
| if (offset_coverage1 < header_end || offset_coverage1 >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ots::ParseCoverageTable(data + offset_coverage1, |
| length - offset_coverage1, |
| file->maxp->num_glyphs)) { |
| return OTS_FAILURE(); |
| } |
| if (offset_coverage2 < header_end || offset_coverage2 >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ots::ParseCoverageTable(data + offset_coverage2, |
| length - offset_coverage2, |
| file->maxp->num_glyphs)) { |
| return OTS_FAILURE(); |
| } |
| |
| if (offset_mark_array < header_end || offset_mark_array >= length) { |
| return OTS_FAILURE(); |
| } |
| if (!ParseMarkArrayTable(data + offset_mark_array, |
| length - offset_mark_array, class_count)) { |
| return OTS_FAILURE(); |
| } |
| |
| if (offset_type_specific_array < header_end || |
| offset_type_specific_array >= length) { |
| return OTS_FAILURE(); |
| } |
| if (type == GPOS_TYPE_MARK_TO_BASE_ATTACHMENT || |
| type == GPOS_TYPE_MARK_TO_MARK_ATTACHMENT) { |
| if (!ParseAnchorArrayTable(data + offset_type_specific_array, |
| length - offset_type_specific_array, |
| class_count)) { |
| return OTS_FAILURE(); |
| } |
| } else if (type == GPOS_TYPE_MARK_TO_LIGATURE_ATTACHMENT) { |
| if (!ParseLigatureArrayTable(data + offset_type_specific_array, |
| length - offset_type_specific_array, |
| class_count)) { |
| return OTS_FAILURE(); |
| } |
| } else { |
| return OTS_FAILURE(); |
| } |
| |
| return true; |
| } |
| |
| // Lookup Type 4: |
| // MarkToBase Attachment Positioning Subtable |
| bool ParseMarkToBaseAttachment(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length) { |
| return ParseMarkToAttachmentSubtables(file, data, length, |
| GPOS_TYPE_MARK_TO_BASE_ATTACHMENT); |
| } |
| |
| // Lookup Type 5: |
| // MarkToLigature Attachment Positioning Subtable |
| bool ParseMarkToLigatureAttachment(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length) { |
| return ParseMarkToAttachmentSubtables(file, data, length, |
| GPOS_TYPE_MARK_TO_LIGATURE_ATTACHMENT); |
| } |
| |
| // Lookup Type 6: |
| // MarkToMark Attachment Positioning Subtable |
| bool ParseMarkToMarkAttachment(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length) { |
| return ParseMarkToAttachmentSubtables(file, data, length, |
| GPOS_TYPE_MARK_TO_MARK_ATTACHMENT); |
| } |
| |
| // Lookup Type 7: |
| // Contextual Positioning Subtables |
| bool ParseContextPositioning(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length) { |
| return ots::ParseContextSubtable(data, length, file->maxp->num_glyphs, |
| file->gpos->num_lookups); |
| } |
| |
| // Lookup Type 8: |
| // Chaining Contexual Positioning Subtable |
| bool ParseChainedContextPositioning(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length) { |
| return ots::ParseChainingContextSubtable(data, length, |
| file->maxp->num_glyphs, |
| file->gpos->num_lookups); |
| } |
| |
| // Lookup Type 9: |
| // Extension Positioning |
| bool ParseExtensionPositioning(const ots::OpenTypeFile *file, |
| const uint8_t *data, const size_t length) { |
| return ots::ParseExtensionSubtable(file, data, length, |
| &kGposLookupSubtableParser); |
| } |
| |
| } // namespace |
| |
| #define DROP_THIS_TABLE \ |
| do { file->gpos->data = 0; file->gpos->length = 0; } while (0) |
| |
| namespace ots { |
| |
| // As far as I checked, following fonts contain invalid GPOS table and |
| // OTS will drop their GPOS table. |
| // |
| // # invalid delta format in device table |
| // samanata.ttf |
| // |
| // # bad size range in device table |
| // Sarai_07.ttf |
| // |
| // # bad offset to PairSetTable |
| // chandas1-2.ttf |
| // |
| // # bad offset to FeatureTable |
| // glrso12.ttf |
| // gllr12.ttf |
| // glbo12.ttf |
| // glb12.ttf |
| // glro12.ttf |
| // glbso12.ttf |
| // glrc12.ttf |
| // glrsc12.ttf |
| // glbs12.ttf |
| // glrs12.ttf |
| // glr12.ttf |
| // |
| // # ScriptRecords aren't sorted by tag |
| // Garogier_unhinted.otf |
| // |
| // # bad start coverage index in CoverageFormat2 |
| // AndBasR.ttf |
| // CharisSILB.ttf |
| // CharisSILBI.ttf |
| // CharisSILI.ttf |
| // CharisSILR.ttf |
| // DoulosSILR.ttf |
| // GenBasBI.ttf |
| // GenBasI.ttf |
| // GenBkBasI.ttf |
| // GenBkBasB.ttf |
| // GenBkBasR.ttf |
| // Padauk-Bold.ttf |
| // Padauk.ttf |
| // |
| // # Contour point indexes aren't sorted |
| // Arial Unicode.ttf |
| |
| bool ots_gpos_parse(OpenTypeFile *file, const uint8_t *data, size_t length) { |
| // Parsing GPOS table requires num_glyphs which is contained in maxp table. |
| if (!file->maxp) { |
| return OTS_FAILURE(); |
| } |
| |
| Buffer table(data, length); |
| |
| OpenTypeGPOS *gpos = new OpenTypeGPOS; |
| file->gpos = gpos; |
| |
| uint32_t version = 0; |
| uint16_t offset_script_list = 0; |
| uint16_t offset_feature_list = 0; |
| uint16_t offset_lookup_list = 0; |
| if (!table.ReadU32(&version) || |
| !table.ReadU16(&offset_script_list) || |
| !table.ReadU16(&offset_feature_list) || |
| !table.ReadU16(&offset_lookup_list)) { |
| return OTS_FAILURE(); |
| } |
| |
| if (version != 0x00010000) { |
| OTS_WARNING("bad GPOS version"); |
| DROP_THIS_TABLE; |
| return true; |
| } |
| if ((offset_script_list < kGposHeaderSize || |
| offset_script_list >= length) || |
| (offset_feature_list < kGposHeaderSize || |
| offset_feature_list >= length) || |
| (offset_lookup_list < kGposHeaderSize || |
| offset_lookup_list >= length)) { |
| OTS_WARNING("bad offset in GPOS header"); |
| DROP_THIS_TABLE; |
| return true; |
| } |
| |
| if (!ParseLookupListTable(file, data + offset_lookup_list, |
| length - offset_lookup_list, |
| &kGposLookupSubtableParser, |
| &gpos->num_lookups)) { |
| OTS_WARNING("faild to parse lookup list table"); |
| DROP_THIS_TABLE; |
| return true; |
| } |
| |
| uint16_t num_features = 0; |
| if (!ParseFeatureListTable(data + offset_feature_list, |
| length - offset_feature_list, gpos->num_lookups, |
| &num_features)) { |
| OTS_WARNING("faild to parse feature list table"); |
| DROP_THIS_TABLE; |
| return true; |
| } |
| |
| if (!ParseScriptListTable(data + offset_script_list, |
| length - offset_script_list, num_features)) { |
| OTS_WARNING("faild to parse script list table"); |
| DROP_THIS_TABLE; |
| return true; |
| } |
| |
| gpos->data = data; |
| gpos->length = length; |
| return true; |
| } |
| |
| bool ots_gpos_should_serialise(OpenTypeFile *file) { |
| const bool needed_tables_dropped = |
| (file->gdef && file->gdef->data == NULL) || |
| (file->gsub && file->gsub->data == NULL); |
| return file->gpos != NULL && file->gpos->data != NULL && |
| !needed_tables_dropped; |
| } |
| |
| bool ots_gpos_serialise(OTSStream *out, OpenTypeFile *file) { |
| if (!out->Write(file->gpos->data, file->gpos->length)) { |
| return OTS_FAILURE(); |
| } |
| |
| return true; |
| } |
| |
| void ots_gpos_free(OpenTypeFile *file) { |
| delete file->gpos; |
| } |
| |
| } // namespace ots |
| |