Line data Source code
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 "vdmx.h"
6 :
7 : // VDMX - Vertical Device Metrics
8 : // http://www.microsoft.com/typography/otspec/vdmx.htm
9 :
10 : #define TABLE_NAME "VDMX"
11 :
12 : #define DROP_THIS_TABLE(...) \
13 : do { \
14 : OTS_FAILURE_MSG_(font->file, TABLE_NAME ": " __VA_ARGS__); \
15 : OTS_FAILURE_MSG("Table discarded"); \
16 : delete font->vdmx; \
17 : font->vdmx = 0; \
18 : } while (0)
19 :
20 : namespace ots {
21 :
22 0 : bool ots_vdmx_parse(Font *font, const uint8_t *data, size_t length) {
23 0 : Buffer table(data, length);
24 0 : font->vdmx = new OpenTypeVDMX;
25 0 : OpenTypeVDMX * const vdmx = font->vdmx;
26 :
27 0 : if (!table.ReadU16(&vdmx->version) ||
28 0 : !table.ReadU16(&vdmx->num_recs) ||
29 0 : !table.ReadU16(&vdmx->num_ratios)) {
30 0 : return OTS_FAILURE_MSG("Failed to read table header");
31 : }
32 :
33 0 : if (vdmx->version > 1) {
34 0 : DROP_THIS_TABLE("bad version: %u", vdmx->version);
35 0 : return true; // continue transcoding
36 : }
37 :
38 0 : vdmx->rat_ranges.reserve(vdmx->num_ratios);
39 0 : for (unsigned i = 0; i < vdmx->num_ratios; ++i) {
40 : OpenTypeVDMXRatioRecord rec;
41 :
42 0 : if (!table.ReadU8(&rec.charset) ||
43 0 : !table.ReadU8(&rec.x_ratio) ||
44 0 : !table.ReadU8(&rec.y_start_ratio) ||
45 0 : !table.ReadU8(&rec.y_end_ratio)) {
46 0 : return OTS_FAILURE_MSG("Failed to read ratio header %d", i);
47 : }
48 :
49 0 : if (rec.charset > 1) {
50 0 : DROP_THIS_TABLE("bad charset: %u", rec.charset);
51 0 : return true;
52 : }
53 :
54 0 : if (rec.y_start_ratio > rec.y_end_ratio) {
55 0 : DROP_THIS_TABLE("bad y ratio");
56 0 : return true;
57 : }
58 :
59 : // All values set to zero signal the default grouping to use;
60 : // if present, this must be the last Ratio group in the table.
61 0 : if ((i < vdmx->num_ratios - 1u) &&
62 0 : (rec.x_ratio == 0) &&
63 0 : (rec.y_start_ratio == 0) &&
64 0 : (rec.y_end_ratio == 0)) {
65 : // workaround for fonts which have 2 or more {0, 0, 0} terminators.
66 0 : DROP_THIS_TABLE("superfluous terminator found");
67 0 : return true;
68 : }
69 :
70 0 : vdmx->rat_ranges.push_back(rec);
71 : }
72 :
73 0 : vdmx->offsets.reserve(vdmx->num_ratios);
74 0 : const size_t current_offset = table.offset();
75 : // current_offset is less than (2 bytes * 3) + (4 bytes * USHRT_MAX) = 256k.
76 0 : for (unsigned i = 0; i < vdmx->num_ratios; ++i) {
77 : uint16_t offset;
78 0 : if (!table.ReadU16(&offset)) {
79 0 : return OTS_FAILURE_MSG("Failed to read ratio offset %d", i);
80 : }
81 0 : if (current_offset + offset >= length) { // thus doesn't overflow.
82 0 : return OTS_FAILURE_MSG("Bad ratio offset %d for ration %d", offset, i);
83 : }
84 :
85 0 : vdmx->offsets.push_back(offset);
86 : }
87 :
88 0 : vdmx->groups.reserve(vdmx->num_recs);
89 0 : for (unsigned i = 0; i < vdmx->num_recs; ++i) {
90 0 : OpenTypeVDMXGroup group;
91 0 : if (!table.ReadU16(&group.recs) ||
92 0 : !table.ReadU8(&group.startsz) ||
93 0 : !table.ReadU8(&group.endsz)) {
94 0 : return OTS_FAILURE_MSG("Failed to read record header %d", i);
95 : }
96 0 : group.entries.reserve(group.recs);
97 0 : for (unsigned j = 0; j < group.recs; ++j) {
98 : OpenTypeVDMXVTable vt;
99 0 : if (!table.ReadU16(&vt.y_pel_height) ||
100 0 : !table.ReadS16(&vt.y_max) ||
101 0 : !table.ReadS16(&vt.y_min)) {
102 0 : return OTS_FAILURE_MSG("Failed to read reacord %d group %d", i, j);
103 : }
104 0 : if (vt.y_max < vt.y_min) {
105 0 : DROP_THIS_TABLE("bad y min/max");
106 0 : return true;
107 : }
108 :
109 : // This table must appear in sorted order (sorted by yPelHeight),
110 : // but need not be continuous.
111 0 : if ((j != 0) && (group.entries[j - 1].y_pel_height >= vt.y_pel_height)) {
112 0 : DROP_THIS_TABLE("the table is not sorted");
113 0 : return true;
114 : }
115 :
116 0 : group.entries.push_back(vt);
117 : }
118 0 : vdmx->groups.push_back(group);
119 : }
120 :
121 0 : return true;
122 : }
123 :
124 0 : bool ots_vdmx_should_serialise(Font *font) {
125 0 : if (!font->glyf) return false; // this table is not for CFF fonts.
126 0 : return font->vdmx != NULL;
127 : }
128 :
129 0 : bool ots_vdmx_serialise(OTSStream *out, Font *font) {
130 0 : OpenTypeVDMX * const vdmx = font->vdmx;
131 :
132 0 : if (!out->WriteU16(vdmx->version) ||
133 0 : !out->WriteU16(vdmx->num_recs) ||
134 0 : !out->WriteU16(vdmx->num_ratios)) {
135 0 : return OTS_FAILURE_MSG("Failed to write table header");
136 : }
137 :
138 0 : for (unsigned i = 0; i < vdmx->rat_ranges.size(); ++i) {
139 0 : const OpenTypeVDMXRatioRecord& rec = vdmx->rat_ranges[i];
140 0 : if (!out->Write(&rec.charset, 1) ||
141 0 : !out->Write(&rec.x_ratio, 1) ||
142 0 : !out->Write(&rec.y_start_ratio, 1) ||
143 0 : !out->Write(&rec.y_end_ratio, 1)) {
144 0 : return OTS_FAILURE_MSG("Failed to write ratio %d", i);
145 : }
146 : }
147 :
148 0 : for (unsigned i = 0; i < vdmx->offsets.size(); ++i) {
149 0 : if (!out->WriteU16(vdmx->offsets[i])) {
150 0 : return OTS_FAILURE_MSG("Failed to write ratio offset %d", i);
151 : }
152 : }
153 :
154 0 : for (unsigned i = 0; i < vdmx->groups.size(); ++i) {
155 0 : const OpenTypeVDMXGroup& group = vdmx->groups[i];
156 0 : if (!out->WriteU16(group.recs) ||
157 0 : !out->Write(&group.startsz, 1) ||
158 0 : !out->Write(&group.endsz, 1)) {
159 0 : return OTS_FAILURE_MSG("Failed to write group %d", i);
160 : }
161 0 : for (unsigned j = 0; j < group.entries.size(); ++j) {
162 0 : const OpenTypeVDMXVTable& vt = group.entries[j];
163 0 : if (!out->WriteU16(vt.y_pel_height) ||
164 0 : !out->WriteS16(vt.y_max) ||
165 0 : !out->WriteS16(vt.y_min)) {
166 0 : return OTS_FAILURE_MSG("Failed to write group %d entry %d", i, j);
167 : }
168 : }
169 : }
170 :
171 0 : return true;
172 : }
173 :
174 0 : void ots_vdmx_reuse(Font *font, Font *other) {
175 0 : font->vdmx = other->vdmx;
176 0 : font->vdmx_reused = true;
177 0 : }
178 :
179 0 : void ots_vdmx_free(Font *font) {
180 0 : delete font->vdmx;
181 0 : }
182 :
183 : } // namespace ots
184 :
185 : #undef TABLE_NAME
186 : #undef DROP_THIS_TABLE
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