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comparison: gfx/ots/src/head.cc
gfx/ots/src/head.cc
- changeset 0
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| -1:000000000000 | 0:f3a322244f4a |
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| 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 "head.h" | |
| 6 | |
| 7 #include <cstring> | |
| 8 | |
| 9 // head - Font Header | |
| 10 // http://www.microsoft.com/typography/otspec/head.htm | |
| 11 | |
| 12 #define TABLE_NAME "head" | |
| 13 | |
| 14 namespace ots { | |
| 15 | |
| 16 bool ots_head_parse(OpenTypeFile *file, const uint8_t *data, size_t length) { | |
| 17 Buffer table(data, length); | |
| 18 file->head = new OpenTypeHEAD; | |
| 19 | |
| 20 uint32_t version = 0; | |
| 21 if (!table.ReadU32(&version) || | |
| 22 !table.ReadU32(&file->head->revision)) { | |
| 23 return OTS_FAILURE_MSG("Failed to read head header"); | |
| 24 } | |
| 25 | |
| 26 if (version >> 16 != 1) { | |
| 27 return OTS_FAILURE_MSG("Bad head table version of %d", version); | |
| 28 } | |
| 29 | |
| 30 // Skip the checksum adjustment | |
| 31 if (!table.Skip(4)) { | |
| 32 return OTS_FAILURE_MSG("Failed to read checksum"); | |
| 33 } | |
| 34 | |
| 35 uint32_t magic; | |
| 36 if (!table.ReadTag(&magic) || | |
| 37 std::memcmp(&magic, "\x5F\x0F\x3C\xF5", 4)) { | |
| 38 return OTS_FAILURE_MSG("Failed to read font magic number"); | |
| 39 } | |
| 40 | |
| 41 if (!table.ReadU16(&file->head->flags)) { | |
| 42 return OTS_FAILURE_MSG("Failed to read head flags"); | |
| 43 } | |
| 44 | |
| 45 // We allow bits 0..4, 11..13 | |
| 46 file->head->flags &= 0x381f; | |
| 47 | |
| 48 if (!table.ReadU16(&file->head->ppem)) { | |
| 49 return OTS_FAILURE_MSG("Failed to read pixels per em"); | |
| 50 } | |
| 51 | |
| 52 // ppem must be in range | |
| 53 if (file->head->ppem < 16 || | |
| 54 file->head->ppem > 16384) { | |
| 55 return OTS_FAILURE_MSG("Bad ppm of %d", file->head->ppem); | |
| 56 } | |
| 57 | |
| 58 // ppem must be a power of two | |
| 59 #if 0 | |
| 60 // We don't call ots_failure() for now since lots of TrueType fonts are | |
| 61 // not following this rule. Putting OTS_WARNING here is too noisy. | |
| 62 if ((file->head->ppem - 1) & file->head->ppem) { | |
| 63 return OTS_FAILURE_MSG("ppm not a power of two: %d", file->head->ppem); | |
| 64 } | |
| 65 #endif | |
| 66 | |
| 67 if (!table.ReadR64(&file->head->created) || | |
| 68 !table.ReadR64(&file->head->modified)) { | |
| 69 return OTS_FAILURE_MSG("Can't read font dates"); | |
| 70 } | |
| 71 | |
| 72 if (!table.ReadS16(&file->head->xmin) || | |
| 73 !table.ReadS16(&file->head->ymin) || | |
| 74 !table.ReadS16(&file->head->xmax) || | |
| 75 !table.ReadS16(&file->head->ymax)) { | |
| 76 return OTS_FAILURE_MSG("Failed to read font bounding box"); | |
| 77 } | |
| 78 | |
| 79 if (file->head->xmin > file->head->xmax) { | |
| 80 return OTS_FAILURE_MSG("Bad x dimension in the font bounding box (%d, %d)", file->head->xmin, file->head->xmax); | |
| 81 } | |
| 82 if (file->head->ymin > file->head->ymax) { | |
| 83 return OTS_FAILURE_MSG("Bad y dimension in the font bounding box (%d, %d)", file->head->ymin, file->head->ymax); | |
| 84 } | |
| 85 | |
| 86 if (!table.ReadU16(&file->head->mac_style)) { | |
| 87 return OTS_FAILURE_MSG("Failed to read font style"); | |
| 88 } | |
| 89 | |
| 90 // We allow bits 0..6 | |
| 91 file->head->mac_style &= 0x7f; | |
| 92 | |
| 93 if (!table.ReadU16(&file->head->min_ppem)) { | |
| 94 return OTS_FAILURE_MSG("Failed to read font minimum ppm"); | |
| 95 } | |
| 96 | |
| 97 // We don't care about the font direction hint | |
| 98 if (!table.Skip(2)) { | |
| 99 return OTS_FAILURE_MSG("Failed to skip font direction hint"); | |
| 100 } | |
| 101 | |
| 102 if (!table.ReadS16(&file->head->index_to_loc_format)) { | |
| 103 return OTS_FAILURE_MSG("Failed to read index to loc format"); | |
| 104 } | |
| 105 if (file->head->index_to_loc_format < 0 || | |
| 106 file->head->index_to_loc_format > 1) { | |
| 107 return OTS_FAILURE_MSG("Bad index to loc format %d", file->head->index_to_loc_format); | |
| 108 } | |
| 109 | |
| 110 int16_t glyph_data_format; | |
| 111 if (!table.ReadS16(&glyph_data_format) || | |
| 112 glyph_data_format) { | |
| 113 return OTS_FAILURE_MSG("Failed to read glyph data format"); | |
| 114 } | |
| 115 | |
| 116 return true; | |
| 117 } | |
| 118 | |
| 119 bool ots_head_should_serialise(OpenTypeFile *file) { | |
| 120 return file->head != NULL; | |
| 121 } | |
| 122 | |
| 123 bool ots_head_serialise(OTSStream *out, OpenTypeFile *file) { | |
| 124 if (!out->WriteU32(0x00010000) || | |
| 125 !out->WriteU32(file->head->revision) || | |
| 126 !out->WriteU32(0) || // check sum not filled in yet | |
| 127 !out->WriteU32(0x5F0F3CF5) || | |
| 128 !out->WriteU16(file->head->flags) || | |
| 129 !out->WriteU16(file->head->ppem) || | |
| 130 !out->WriteR64(file->head->created) || | |
| 131 !out->WriteR64(file->head->modified) || | |
| 132 !out->WriteS16(file->head->xmin) || | |
| 133 !out->WriteS16(file->head->ymin) || | |
| 134 !out->WriteS16(file->head->xmax) || | |
| 135 !out->WriteS16(file->head->ymax) || | |
| 136 !out->WriteU16(file->head->mac_style) || | |
| 137 !out->WriteU16(file->head->min_ppem) || | |
| 138 !out->WriteS16(2) || | |
| 139 !out->WriteS16(file->head->index_to_loc_format) || | |
| 140 !out->WriteS16(0)) { | |
| 141 return OTS_FAILURE_MSG("Failed to write head table"); | |
| 142 } | |
| 143 | |
| 144 return true; | |
| 145 } | |
| 146 | |
| 147 void ots_head_free(OpenTypeFile *file) { | |
| 148 delete file->head; | |
| 149 } | |
| 150 | |
| 151 } // namespace |
