Line data Source code
1 : // Copyright (c) 2011 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 "metrics.h"
6 :
7 : #include "head.h"
8 : #include "maxp.h"
9 :
10 : // OpenType horizontal and vertical common header format
11 : // http://www.microsoft.com/typography/otspec/hhea.htm
12 : // http://www.microsoft.com/typography/otspec/vhea.htm
13 :
14 : #define TABLE_NAME "metrics" // XXX: use individual table names
15 :
16 : namespace ots {
17 :
18 0 : bool ParseMetricsHeader(Font *font, Buffer *table,
19 : OpenTypeMetricsHeader *header) {
20 0 : if (!table->ReadS16(&header->ascent) ||
21 0 : !table->ReadS16(&header->descent) ||
22 0 : !table->ReadS16(&header->linegap) ||
23 0 : !table->ReadU16(&header->adv_width_max) ||
24 0 : !table->ReadS16(&header->min_sb1) ||
25 0 : !table->ReadS16(&header->min_sb2) ||
26 0 : !table->ReadS16(&header->max_extent) ||
27 0 : !table->ReadS16(&header->caret_slope_rise) ||
28 0 : !table->ReadS16(&header->caret_slope_run) ||
29 0 : !table->ReadS16(&header->caret_offset)) {
30 0 : return OTS_FAILURE_MSG("Failed to read metrics header");
31 : }
32 :
33 0 : if (header->ascent < 0) {
34 0 : OTS_WARNING("bad ascent: %d", header->ascent);
35 0 : header->ascent = 0;
36 : }
37 0 : if (header->linegap < 0) {
38 0 : OTS_WARNING("bad linegap: %d", header->linegap);
39 0 : header->linegap = 0;
40 : }
41 :
42 0 : if (!font->head) {
43 0 : return OTS_FAILURE_MSG("Missing head font table");
44 : }
45 :
46 : // if the font is non-slanted, caret_offset should be zero.
47 0 : if (!(font->head->mac_style & 2) &&
48 0 : (header->caret_offset != 0)) {
49 0 : OTS_WARNING("bad caret offset: %d", header->caret_offset);
50 0 : header->caret_offset = 0;
51 : }
52 :
53 : // skip the reserved bytes
54 0 : if (!table->Skip(8)) {
55 0 : return OTS_FAILURE_MSG("Failed to skip reserverd bytes");
56 : }
57 :
58 : int16_t data_format;
59 0 : if (!table->ReadS16(&data_format)) {
60 0 : return OTS_FAILURE_MSG("Failed to read data format");
61 : }
62 0 : if (data_format) {
63 0 : return OTS_FAILURE_MSG("Bad data format %d", data_format);
64 : }
65 :
66 0 : if (!table->ReadU16(&header->num_metrics)) {
67 0 : return OTS_FAILURE_MSG("Failed to read number of metrics");
68 : }
69 :
70 0 : if (!font->maxp) {
71 0 : return OTS_FAILURE_MSG("Missing maxp font table");
72 : }
73 :
74 0 : if (header->num_metrics > font->maxp->num_glyphs) {
75 0 : return OTS_FAILURE_MSG("Bad number of metrics %d", header->num_metrics);
76 : }
77 :
78 0 : return true;
79 : }
80 :
81 0 : bool SerialiseMetricsHeader(const ots::Font *font,
82 : OTSStream *out,
83 : const OpenTypeMetricsHeader *header) {
84 0 : if (!out->WriteU32(header->version) ||
85 0 : !out->WriteS16(header->ascent) ||
86 0 : !out->WriteS16(header->descent) ||
87 0 : !out->WriteS16(header->linegap) ||
88 0 : !out->WriteU16(header->adv_width_max) ||
89 0 : !out->WriteS16(header->min_sb1) ||
90 0 : !out->WriteS16(header->min_sb2) ||
91 0 : !out->WriteS16(header->max_extent) ||
92 0 : !out->WriteS16(header->caret_slope_rise) ||
93 0 : !out->WriteS16(header->caret_slope_run) ||
94 0 : !out->WriteS16(header->caret_offset) ||
95 0 : !out->WriteR64(0) || // reserved
96 0 : !out->WriteS16(0) || // metric data format
97 0 : !out->WriteU16(header->num_metrics)) {
98 0 : return OTS_FAILURE_MSG("Failed to write metrics");
99 : }
100 :
101 0 : return true;
102 : }
103 :
104 0 : bool ParseMetricsTable(const ots::Font *font,
105 : Buffer *table,
106 : const uint16_t num_glyphs,
107 : const OpenTypeMetricsHeader *header,
108 : OpenTypeMetricsTable *metrics) {
109 : // |num_metrics| is a uint16_t, so it's bounded < 65536. This limits that
110 : // amount of memory that we'll allocate for this to a sane amount.
111 0 : const unsigned num_metrics = header->num_metrics;
112 :
113 0 : if (num_metrics > num_glyphs) {
114 0 : return OTS_FAILURE_MSG("Bad number of metrics %d", num_metrics);
115 : }
116 0 : if (!num_metrics) {
117 0 : return OTS_FAILURE_MSG("No metrics!");
118 : }
119 0 : const unsigned num_sbs = num_glyphs - num_metrics;
120 :
121 0 : metrics->entries.reserve(num_metrics);
122 0 : for (unsigned i = 0; i < num_metrics; ++i) {
123 0 : uint16_t adv = 0;
124 0 : int16_t sb = 0;
125 0 : if (!table->ReadU16(&adv) || !table->ReadS16(&sb)) {
126 0 : return OTS_FAILURE_MSG("Failed to read metric %d", i);
127 : }
128 0 : metrics->entries.push_back(std::make_pair(adv, sb));
129 : }
130 :
131 0 : metrics->sbs.reserve(num_sbs);
132 0 : for (unsigned i = 0; i < num_sbs; ++i) {
133 : int16_t sb;
134 0 : if (!table->ReadS16(&sb)) {
135 : // Some Japanese fonts (e.g., mona.ttf) fail this test.
136 0 : return OTS_FAILURE_MSG("Failed to read side bearing %d", i + num_metrics);
137 : }
138 0 : metrics->sbs.push_back(sb);
139 : }
140 :
141 0 : return true;
142 : }
143 :
144 0 : bool SerialiseMetricsTable(const ots::Font *font,
145 : OTSStream *out,
146 : const OpenTypeMetricsTable *metrics) {
147 0 : for (unsigned i = 0; i < metrics->entries.size(); ++i) {
148 0 : if (!out->WriteU16(metrics->entries[i].first) ||
149 0 : !out->WriteS16(metrics->entries[i].second)) {
150 0 : return OTS_FAILURE_MSG("Failed to write metric %d", i);
151 : }
152 : }
153 :
154 0 : for (unsigned i = 0; i < metrics->sbs.size(); ++i) {
155 0 : if (!out->WriteS16(metrics->sbs[i])) {
156 0 : return OTS_FAILURE_MSG("Failed to write side bearing %ld", i + metrics->entries.size());
157 : }
158 : }
159 :
160 0 : return true;
161 : }
162 :
163 : } // namespace ots
164 :
165 : #undef TABLE_NAME
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