1 // Copyright (c) 2009 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "post.h" 6 7 #include "maxp.h" 8 9 // post - PostScript 10 // http://www.microsoft.com/opentype/otspec/post.htm 11 12 namespace ots { 13 14 bool ots_post_parse(OpenTypeFile *file, const uint8_t *data, size_t length) { 15 Buffer table(data, length); 16 17 OpenTypePOST *post = new OpenTypePOST; 18 file->post = post; 19 20 if (!table.ReadU32(&post->version) || 21 !table.ReadU32(&post->italic_angle) || 22 !table.ReadS16(&post->underline) || 23 !table.ReadS16(&post->underline_thickness) || 24 !table.ReadU32(&post->is_fixed_pitch)) { 25 return OTS_FAILURE(); 26 } 27 28 if (post->underline_thickness < 0) { 29 post->underline_thickness = 1; 30 } 31 32 if (post->version == 0x00010000) { 33 return true; 34 } else if (post->version == 0x00030000) { 35 return true; 36 } else if (post->version != 0x00020000) { 37 // 0x00025000 is deprecated. We don't accept it. 38 return OTS_FAILURE(); 39 } 40 41 // We have a version 2 table with a list of Pascal strings at the end 42 43 // We don't care about the memory usage fields. We'll set all these to zero 44 // when serialising 45 if (!table.Skip(16)) { 46 return OTS_FAILURE(); 47 } 48 49 uint16_t num_glyphs = 0; 50 if (!table.ReadU16(&num_glyphs)) { 51 return OTS_FAILURE(); 52 } 53 54 if (!file->maxp) { 55 return OTS_FAILURE(); 56 } 57 58 if (num_glyphs == 0) { 59 if (file->maxp->num_glyphs > 258) { 60 return OTS_FAILURE(); 61 } 62 OTS_WARNING("table version is 1, but no glyf names are found"); 63 // workaround for fonts in http://www.fontsquirrel.com/fontface 64 // (e.g., yataghan.ttf). 65 post->version = 0x00010000; 66 return true; 67 } 68 69 if (num_glyphs != file->maxp->num_glyphs) { 70 // Note: Fixedsys500c.ttf seems to have inconsistent num_glyphs values. 71 return OTS_FAILURE(); 72 } 73 74 post->glyph_name_index.resize(num_glyphs); 75 for (unsigned i = 0; i < num_glyphs; ++i) { 76 if (!table.ReadU16(&post->glyph_name_index[i])) { 77 return OTS_FAILURE(); 78 } 79 // Note: A strict interpretation of the specification requires name indexes 80 // are less than 32768. This, however, excludes fonts like unifont.ttf 81 // which cover all of unicode. 82 } 83 84 // Now we have an array of Pascal strings. We have to check that they are all 85 // valid and read them in. 86 const size_t strings_offset = table.offset(); 87 const uint8_t *strings = data + strings_offset; 88 const uint8_t *strings_end = data + length; 89 90 for (;;) { 91 if (strings == strings_end) break; 92 const unsigned string_length = *strings; 93 if (strings + 1 + string_length > strings_end) { 94 return OTS_FAILURE(); 95 } 96 if (std::memchr(strings + 1, '\0', string_length)) { 97 return OTS_FAILURE(); 98 } 99 post->names.push_back( 100 std::string(reinterpret_cast<const char*>(strings + 1), string_length)); 101 strings += 1 + string_length; 102 } 103 const unsigned num_strings = post->names.size(); 104 105 // check that all the references are within bounds 106 for (unsigned i = 0; i < num_glyphs; ++i) { 107 unsigned offset = post->glyph_name_index[i]; 108 if (offset < 258) { 109 continue; 110 } 111 112 offset -= 258; 113 if (offset >= num_strings) { 114 return OTS_FAILURE(); 115 } 116 } 117 118 return true; 119 } 120 121 bool ots_post_should_serialise(OpenTypeFile *file) { 122 return file->post != NULL; 123 } 124 125 bool ots_post_serialise(OTSStream *out, OpenTypeFile *file) { 126 const OpenTypePOST *post = file->post; 127 128 // OpenType with CFF glyphs must have v3 post table. 129 if (file->post && file->cff && file->post->version != 0x00030000) { 130 return OTS_FAILURE(); 131 } 132 133 if (!out->WriteU32(post->version) || 134 !out->WriteU32(post->italic_angle) || 135 !out->WriteS16(post->underline) || 136 !out->WriteS16(post->underline_thickness) || 137 !out->WriteU32(post->is_fixed_pitch) || 138 !out->WriteU32(0) || 139 !out->WriteU32(0) || 140 !out->WriteU32(0) || 141 !out->WriteU32(0)) { 142 return OTS_FAILURE(); 143 } 144 145 if (post->version != 0x00020000) { 146 return true; // v1.0 and v3.0 does not have glyph names. 147 } 148 149 if (!out->WriteU16(post->glyph_name_index.size())) { 150 return OTS_FAILURE(); 151 } 152 153 for (unsigned i = 0; i < post->glyph_name_index.size(); ++i) { 154 if (!out->WriteU16(post->glyph_name_index[i])) { 155 return OTS_FAILURE(); 156 } 157 } 158 159 // Now we just have to write out the strings in the correct order 160 for (unsigned i = 0; i < post->names.size(); ++i) { 161 const std::string& s = post->names[i]; 162 const uint8_t string_length = s.size(); 163 if (!out->Write(&string_length, 1)) { 164 return OTS_FAILURE(); 165 } 166 // Some ttf fonts (e.g., frank.ttf on Windows Vista) have zero-length name. 167 // We allow them. 168 if (string_length > 0 && !out->Write(s.data(), string_length)) { 169 return OTS_FAILURE(); 170 } 171 } 172 173 return true; 174 } 175 176 void ots_post_free(OpenTypeFile *file) { 177 delete file->post; 178 } 179 180 } // namespace ots 181
