yusukes@chromium.org | d257d18 | 2009-11-04 04:56:32 +0000 | [diff] [blame] | 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/opentype/otspec/head.htm |
| 11 | |
| 12 | namespace ots { |
| 13 | |
| 14 | bool ots_head_parse(OpenTypeFile *file, const uint8_t *data, size_t length) { |
| 15 | Buffer table(data, length); |
| 16 | file->head = new OpenTypeHEAD; |
| 17 | |
yusukes@chromium.org | 8ad0a17 | 2009-11-04 06:07:58 +0000 | [diff] [blame] | 18 | uint32_t version = 0; |
yusukes@chromium.org | d257d18 | 2009-11-04 04:56:32 +0000 | [diff] [blame] | 19 | if (!table.ReadU32(&version) || |
| 20 | !table.ReadU32(&file->head->revision)) { |
| 21 | return OTS_FAILURE(); |
| 22 | } |
| 23 | |
| 24 | if (version >> 16 != 1) { |
| 25 | return OTS_FAILURE(); |
| 26 | } |
| 27 | |
| 28 | // Skip the checksum adjustment |
| 29 | if (!table.Skip(4)) { |
| 30 | return OTS_FAILURE(); |
| 31 | } |
| 32 | |
| 33 | uint32_t magic; |
| 34 | if (!table.ReadTag(&magic) || |
| 35 | std::memcmp(&magic, "\x5F\x0F\x3C\xF5", 4)) { |
| 36 | return OTS_FAILURE(); |
| 37 | } |
| 38 | |
| 39 | if (!table.ReadU16(&file->head->flags)) { |
| 40 | return OTS_FAILURE(); |
| 41 | } |
| 42 | |
| 43 | // We allow bits 0..4, 11..13 |
| 44 | file->head->flags &= 0x381f; |
| 45 | |
| 46 | if (!table.ReadU16(&file->head->ppem)) { |
| 47 | return OTS_FAILURE(); |
| 48 | } |
| 49 | |
| 50 | // ppem must be in range |
| 51 | if (file->head->ppem < 16 || |
| 52 | file->head->ppem > 16384) { |
| 53 | return OTS_FAILURE(); |
| 54 | } |
| 55 | |
| 56 | // ppem must be a power of two |
yusukes@chromium.org | a4099a3 | 2009-11-12 01:43:51 +0000 | [diff] [blame] | 57 | #if 0 |
| 58 | // We don't call ots_failure() for now since lots of TrueType fonts are |
| 59 | // not following this rule. Putting OTS_WARNING here is too noisy. |
yusukes@chromium.org | d257d18 | 2009-11-04 04:56:32 +0000 | [diff] [blame] | 60 | if ((file->head->ppem - 1) & file->head->ppem) { |
yusukes@chromium.org | a4099a3 | 2009-11-12 01:43:51 +0000 | [diff] [blame] | 61 | return OTS_FAILURE(); |
yusukes@chromium.org | d257d18 | 2009-11-04 04:56:32 +0000 | [diff] [blame] | 62 | } |
yusukes@chromium.org | a4099a3 | 2009-11-12 01:43:51 +0000 | [diff] [blame] | 63 | #endif |
yusukes@chromium.org | d257d18 | 2009-11-04 04:56:32 +0000 | [diff] [blame] | 64 | |
| 65 | if (!table.ReadR64(&file->head->created) || |
| 66 | !table.ReadR64(&file->head->modified)) { |
| 67 | return OTS_FAILURE(); |
| 68 | } |
| 69 | |
| 70 | if (!table.ReadS16(&file->head->xmin) || |
| 71 | !table.ReadS16(&file->head->ymin) || |
| 72 | !table.ReadS16(&file->head->xmax) || |
| 73 | !table.ReadS16(&file->head->ymax)) { |
| 74 | return OTS_FAILURE(); |
| 75 | } |
| 76 | |
| 77 | if (file->head->xmin > file->head->xmax) { |
| 78 | return OTS_FAILURE(); |
| 79 | } |
| 80 | if (file->head->ymin > file->head->ymax) { |
| 81 | return OTS_FAILURE(); |
| 82 | } |
| 83 | |
| 84 | if (!table.ReadU16(&file->head->mac_style)) { |
| 85 | return OTS_FAILURE(); |
| 86 | } |
| 87 | |
| 88 | // We allow bits 0..6 |
| 89 | file->head->mac_style &= 0x7f; |
| 90 | |
| 91 | if (!table.ReadU16(&file->head->min_ppem)) { |
| 92 | return OTS_FAILURE(); |
| 93 | } |
| 94 | |
| 95 | // We don't care about the font direction hint |
| 96 | if (!table.Skip(2)) { |
| 97 | return OTS_FAILURE(); |
| 98 | } |
| 99 | |
| 100 | if (!table.ReadS16(&file->head->index_to_loc_format)) { |
| 101 | return OTS_FAILURE(); |
| 102 | } |
| 103 | if (file->head->index_to_loc_format < 0 || |
| 104 | file->head->index_to_loc_format > 1) { |
| 105 | return OTS_FAILURE(); |
| 106 | } |
| 107 | |
| 108 | int16_t glyph_data_format; |
| 109 | if (!table.ReadS16(&glyph_data_format) || |
| 110 | glyph_data_format) { |
| 111 | return OTS_FAILURE(); |
| 112 | } |
| 113 | |
| 114 | return true; |
| 115 | } |
| 116 | |
| 117 | bool ots_head_should_serialise(OpenTypeFile *file) { |
agl@chromium.org | 2beaf1d | 2011-01-21 17:19:34 +0000 | [diff] [blame] | 118 | return file->head != NULL; |
yusukes@chromium.org | d257d18 | 2009-11-04 04:56:32 +0000 | [diff] [blame] | 119 | } |
| 120 | |
| 121 | bool ots_head_serialise(OTSStream *out, OpenTypeFile *file) { |
| 122 | if (!out->WriteU32(0x00010000) || |
| 123 | !out->WriteU32(file->head->revision) || |
| 124 | !out->WriteU32(0) || // check sum not filled in yet |
| 125 | !out->WriteU32(0x5F0F3CF5) || |
| 126 | !out->WriteU16(file->head->flags) || |
| 127 | !out->WriteU16(file->head->ppem) || |
| 128 | !out->WriteR64(file->head->created) || |
| 129 | !out->WriteR64(file->head->modified) || |
| 130 | !out->WriteS16(file->head->xmin) || |
| 131 | !out->WriteS16(file->head->ymin) || |
| 132 | !out->WriteS16(file->head->xmax) || |
| 133 | !out->WriteS16(file->head->ymax) || |
| 134 | !out->WriteU16(file->head->mac_style) || |
| 135 | !out->WriteU16(file->head->min_ppem) || |
| 136 | !out->WriteS16(2) || |
| 137 | !out->WriteS16(file->head->index_to_loc_format) || |
| 138 | !out->WriteS16(0)) { |
| 139 | return OTS_FAILURE(); |
| 140 | } |
| 141 | |
| 142 | return true; |
| 143 | } |
| 144 | |
| 145 | void ots_head_free(OpenTypeFile *file) { |
| 146 | delete file->head; |
| 147 | } |
| 148 | |
| 149 | } // namespace |