1 /*
2  * Copyright 2012 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #include "src/sfnt/SkOTUtils.h"
9 
10 #include "include/core/SkData.h"
11 #include "include/core/SkStream.h"
12 #include "include/private/SkTo.h"
13 #include "src/core/SkAdvancedTypefaceMetrics.h"
14 #include "src/core/SkEndian.h"
15 #include "src/sfnt/SkOTTableTypes.h"
16 #include "src/sfnt/SkOTTable_head.h"
17 #include "src/sfnt/SkOTTable_name.h"
18 #include "src/sfnt/SkSFNTHeader.h"
19 
20 extern const uint8_t SK_OT_GlyphData_NoOutline[] = {
21     0x0,0x0, //SkOTTableGlyphData::numberOfContours
22     0x0,0x0, //SkOTTableGlyphData::xMin
23     0x0,0x0, //SkOTTableGlyphData::yMin
24     0x0,0x0, //SkOTTableGlyphData::xMax
25     0x0,0x0, //SkOTTableGlyphData::yMax
26 
27     0x0,0x0, //SkOTTableGlyphDataInstructions::length
28 };
29 
CalcTableChecksum(SK_OT_ULONG * data,size_t length)30 uint32_t SkOTUtils::CalcTableChecksum(SK_OT_ULONG *data, size_t length) {
31     uint32_t sum = 0;
32     SK_OT_ULONG *dataEnd = data + ((length + 3) & ~3) / sizeof(SK_OT_ULONG);
33     for (; data < dataEnd; ++data) {
34         sum += SkEndian_SwapBE32(*data);
35     }
36     return sum;
37 }
38 
RenameFont(SkStreamAsset * fontData,const char * fontName,int fontNameLen)39 SkData* SkOTUtils::RenameFont(SkStreamAsset* fontData, const char* fontName, int fontNameLen) {
40 
41     // Get the sfnt header.
42     SkSFNTHeader sfntHeader;
43     if (fontData->read(&sfntHeader, sizeof(sfntHeader)) < sizeof(sfntHeader)) {
44         return nullptr;
45     }
46 
47     // Find the existing 'name' table.
48     int tableIndex;
49     SkSFNTHeader::TableDirectoryEntry tableEntry;
50     int numTables = SkEndian_SwapBE16(sfntHeader.numTables);
51     for (tableIndex = 0; tableIndex < numTables; ++tableIndex) {
52         if (fontData->read(&tableEntry, sizeof(tableEntry)) < sizeof(tableEntry)) {
53             return nullptr;
54         }
55         if (SkOTTableName::TAG == tableEntry.tag) {
56             break;
57         }
58     }
59     if (tableIndex == numTables) {
60         return nullptr;
61     }
62 
63     if (!fontData->rewind()) {
64         return nullptr;
65     }
66 
67     // The required 'name' record types: Family, Style, Unique, Full and PostScript.
68     static constexpr std::array<SkOTTableName::Record::NameID::Predefined::Value, 5> names{{
69         SkOTTableName::Record::NameID::Predefined::FontFamilyName,
70         SkOTTableName::Record::NameID::Predefined::FontSubfamilyName,
71         SkOTTableName::Record::NameID::Predefined::UniqueFontIdentifier,
72         SkOTTableName::Record::NameID::Predefined::FullFontName,
73         SkOTTableName::Record::NameID::Predefined::PostscriptName,
74     }};
75 
76     // GDI will not use a Symbol cmap table if there is no Symbol encoded name.
77     static constexpr std::array<SkOTTableName::Record::EncodingID::Windows::Value, 2> encodings{{
78         SkOTTableName::Record::EncodingID::Windows::Symbol,
79         SkOTTableName::Record::EncodingID::Windows::UnicodeBMPUCS2,
80     }};
81 
82     // Copy the data, leaving out the old name table.
83     // In theory, we could also remove the DSIG table if it exists.
84     size_t nameTableLogicalSize = sizeof(SkOTTableName)
85                                 + (encodings.size() * names.size() * sizeof(SkOTTableName::Record))
86                                 + (fontNameLen * sizeof(SK_OT_USHORT));
87     size_t nameTablePhysicalSize = (nameTableLogicalSize + 3) & ~3; // Rounded up to a multiple of 4.
88 
89     size_t oldNameTablePhysicalSize = (SkEndian_SwapBE32(tableEntry.logicalLength) + 3) & ~3; // Rounded up to a multiple of 4.
90     size_t oldNameTableOffset = SkEndian_SwapBE32(tableEntry.offset);
91 
92     //originalDataSize is the size of the original data without the name table.
93     size_t originalDataSize = fontData->getLength() - oldNameTablePhysicalSize;
94     size_t newDataSize = originalDataSize + nameTablePhysicalSize;
95 
96     auto rewrittenFontData = SkData::MakeUninitialized(newDataSize);
97     SK_OT_BYTE* data = static_cast<SK_OT_BYTE*>(rewrittenFontData->writable_data());
98 
99     if (fontData->read(data, oldNameTableOffset) < oldNameTableOffset) {
100         return nullptr;
101     }
102     if (fontData->skip(oldNameTablePhysicalSize) < oldNameTablePhysicalSize) {
103         return nullptr;
104     }
105     if (fontData->read(data + oldNameTableOffset, originalDataSize - oldNameTableOffset) < originalDataSize - oldNameTableOffset) {
106         return nullptr;
107     }
108 
109     //Fix up the offsets of the directory entries after the old 'name' table entry.
110     SkSFNTHeader::TableDirectoryEntry* currentEntry = reinterpret_cast<SkSFNTHeader::TableDirectoryEntry*>(data + sizeof(SkSFNTHeader));
111     SkSFNTHeader::TableDirectoryEntry* endEntry = currentEntry + numTables;
112     SkSFNTHeader::TableDirectoryEntry* headTableEntry = nullptr;
113     for (; currentEntry < endEntry; ++currentEntry) {
114         uint32_t oldOffset = SkEndian_SwapBE32(currentEntry->offset);
115         if (oldOffset > oldNameTableOffset) {
116             currentEntry->offset = SkEndian_SwapBE32(SkToU32(oldOffset - oldNameTablePhysicalSize));
117         }
118 
119         if (SkOTTableHead::TAG == currentEntry->tag) {
120             headTableEntry = currentEntry;
121         }
122     }
123 
124     // Make the table directory entry point to the new 'name' table.
125     SkSFNTHeader::TableDirectoryEntry* nameTableEntry = reinterpret_cast<SkSFNTHeader::TableDirectoryEntry*>(data + sizeof(SkSFNTHeader)) + tableIndex;
126     nameTableEntry->logicalLength = SkEndian_SwapBE32(SkToU32(nameTableLogicalSize));
127     nameTableEntry->offset = SkEndian_SwapBE32(SkToU32(originalDataSize));
128 
129     // Write the new 'name' table after the original font data.
130     SkOTTableName* nameTable = reinterpret_cast<SkOTTableName*>(data + originalDataSize);
131     unsigned short stringOffset = sizeof(SkOTTableName) + (encodings.size() * names.size() * sizeof(SkOTTableName::Record));
132     nameTable->format = SkOTTableName::format_0;
133     nameTable->count = SkEndian_SwapBE16(encodings.size() * names.size());
134     nameTable->stringOffset = SkEndian_SwapBE16(stringOffset);
135 
136     SkOTTableName::Record* nameRecord = reinterpret_cast<SkOTTableName::Record*>(data + originalDataSize + sizeof(SkOTTableName));
137     for (const auto& encoding : encodings) {
138         for (const auto& name : names) {
139             nameRecord->platformID.value = SkOTTableName::Record::PlatformID::Windows;
140             nameRecord->encodingID.windows.value = encoding;
141             nameRecord->languageID.windows.value = SkOTTableName::Record::LanguageID::Windows::English_UnitedStates;
142             nameRecord->nameID.predefined.value = name;
143             nameRecord->offset = SkEndian_SwapBE16(0);
144             nameRecord->length = SkEndian_SwapBE16(SkToU16(fontNameLen * sizeof(SK_OT_USHORT)));
145             ++nameRecord;
146         }
147     }
148 
149     SK_OT_USHORT* nameString = reinterpret_cast<SK_OT_USHORT*>(data + originalDataSize + stringOffset);
150     for (int i = 0; i < fontNameLen; ++i) {
151         nameString[i] = SkEndian_SwapBE16(fontName[i]);
152     }
153 
154     unsigned char* logical = data + originalDataSize + nameTableLogicalSize;
155     unsigned char* physical = data + originalDataSize + nameTablePhysicalSize;
156     for (; logical < physical; ++logical) {
157         *logical = 0;
158     }
159 
160     // Update the table checksum in the directory entry.
161     nameTableEntry->checksum = SkEndian_SwapBE32(SkOTUtils::CalcTableChecksum(reinterpret_cast<SK_OT_ULONG*>(nameTable), nameTableLogicalSize));
162 
163     // Update the checksum adjustment in the head table.
164     if (headTableEntry) {
165         size_t headTableOffset = SkEndian_SwapBE32(headTableEntry->offset);
166         if (headTableOffset + sizeof(SkOTTableHead) < originalDataSize) {
167             SkOTTableHead* headTable = reinterpret_cast<SkOTTableHead*>(data + headTableOffset);
168             headTable->checksumAdjustment = SkEndian_SwapBE32(0);
169             uint32_t unadjustedFontChecksum = SkOTUtils::CalcTableChecksum(reinterpret_cast<SK_OT_ULONG*>(data), originalDataSize + nameTablePhysicalSize);
170             headTable->checksumAdjustment = SkEndian_SwapBE32(SkOTTableHead::fontChecksum - unadjustedFontChecksum);
171         }
172     }
173 
174     return rewrittenFontData.release();
175 }
176 
177 sk_sp<SkOTUtils::LocalizedStrings_NameTable>
Make(const SkTypeface & typeface,SK_OT_USHORT types[],int typesCount)178 SkOTUtils::LocalizedStrings_NameTable::Make(const SkTypeface& typeface,
179                                             SK_OT_USHORT types[],
180                                             int typesCount)
181 {
182     static const SkFontTableTag nameTag = SkSetFourByteTag('n','a','m','e');
183     size_t nameTableSize = typeface.getTableSize(nameTag);
184     if (0 == nameTableSize) {
185         return nullptr;
186     }
187     std::unique_ptr<uint8_t[]> nameTableData(new uint8_t[nameTableSize]);
188     size_t copied = typeface.getTableData(nameTag, 0, nameTableSize, nameTableData.get());
189     if (copied != nameTableSize) {
190         return nullptr;
191     }
192 
193     return sk_sp<SkOTUtils::LocalizedStrings_NameTable>(
194         new SkOTUtils::LocalizedStrings_NameTable(std::move(nameTableData), nameTableSize,
195                                                   types, typesCount));
196 }
197 
198 sk_sp<SkOTUtils::LocalizedStrings_NameTable>
MakeForFamilyNames(const SkTypeface & typeface)199 SkOTUtils::LocalizedStrings_NameTable::MakeForFamilyNames(const SkTypeface& typeface) {
200     return Make(typeface,
201                 SkOTUtils::LocalizedStrings_NameTable::familyNameTypes,
202                 SK_ARRAY_COUNT(SkOTUtils::LocalizedStrings_NameTable::familyNameTypes));
203 }
204 
next(SkTypeface::LocalizedString * localizedString)205 bool SkOTUtils::LocalizedStrings_NameTable::next(SkTypeface::LocalizedString* localizedString) {
206     do {
207         SkOTTableName::Iterator::Record record;
208         if (fFamilyNameIter.next(record)) {
209             localizedString->fString = record.name;
210             localizedString->fLanguage = record.language;
211             return true;
212         }
213         if (fTypesCount == fTypesIndex + 1) {
214             return false;
215         }
216         ++fTypesIndex;
217         fFamilyNameIter.reset(fTypes[fTypesIndex]);
218     } while (true);
219 }
220 
221 SK_OT_USHORT SkOTUtils::LocalizedStrings_NameTable::familyNameTypes[3] = {
222     SkOTTableName::Record::NameID::Predefined::FontFamilyName,
223     SkOTTableName::Record::NameID::Predefined::PreferredFamily,
224     SkOTTableName::Record::NameID::Predefined::WWSFamilyName,
225 };
226 
SetAdvancedTypefaceFlags(SkOTTableOS2_V4::Type fsType,SkAdvancedTypefaceMetrics * info)227 void SkOTUtils::SetAdvancedTypefaceFlags(SkOTTableOS2_V4::Type fsType,
228                                          SkAdvancedTypefaceMetrics* info) {
229     SkASSERT(info);
230     // The logic should be identical to SkTypeface_FreeType::onGetAdvancedMetrics().
231     if (fsType.raw.value != 0) {
232         if (SkToBool(fsType.field.Restricted) || SkToBool(fsType.field.Bitmap)) {
233             info->fFlags |= SkAdvancedTypefaceMetrics::kNotEmbeddable_FontFlag;
234         }
235         if (SkToBool(fsType.field.NoSubsetting)) {
236             info->fFlags |= SkAdvancedTypefaceMetrics::kNotSubsettable_FontFlag;
237         }
238     }
239 }
240