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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 "os2.h"
6 
7 #include "head.h"
8 
9 // OS/2 - OS/2 and Windows Metrics
10 // http://www.microsoft.com/opentype/otspec/os2.htm
11 
12 namespace ots {
13 
ots_os2_parse(OpenTypeFile * file,const uint8_t * data,size_t length)14 bool ots_os2_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
15   Buffer table(data, length);
16 
17   OpenTypeOS2 *os2 = new OpenTypeOS2;
18   file->os2 = os2;
19 
20   if (!table.ReadU16(&os2->version) ||
21       !table.ReadS16(&os2->avg_char_width) ||
22       !table.ReadU16(&os2->weight_class) ||
23       !table.ReadU16(&os2->width_class) ||
24       !table.ReadU16(&os2->type) ||
25       !table.ReadS16(&os2->subscript_x_size) ||
26       !table.ReadS16(&os2->subscript_y_size) ||
27       !table.ReadS16(&os2->subscript_x_offset) ||
28       !table.ReadS16(&os2->subscript_y_offset) ||
29       !table.ReadS16(&os2->superscript_x_size) ||
30       !table.ReadS16(&os2->superscript_y_size) ||
31       !table.ReadS16(&os2->superscript_x_offset) ||
32       !table.ReadS16(&os2->superscript_y_offset) ||
33       !table.ReadS16(&os2->strikeout_size) ||
34       !table.ReadS16(&os2->strikeout_position) ||
35       !table.ReadS16(&os2->family_class)) {
36     return OTS_FAILURE();
37   }
38 
39   if (os2->version > 4) {
40     return OTS_FAILURE();
41   }
42 
43   // Some linux fonts (e.g., Kedage-t.ttf and LucidaSansDemiOblique.ttf) have
44   // weird weight/width classes. Overwrite them with FW_NORMAL/1/9.
45   if (os2->weight_class < 100 ||
46       os2->weight_class > 900 ||
47       os2->weight_class % 100) {
48     OTS_WARNING("bad weight: %u", os2->weight_class);
49     os2->weight_class = 400;  // FW_NORMAL
50   }
51   if (os2->width_class < 1) {
52     OTS_WARNING("bad width: %u", os2->width_class);
53     os2->width_class = 1;
54   } else if (os2->width_class > 9) {
55     OTS_WARNING("bad width: %u", os2->width_class);
56     os2->width_class = 9;
57   }
58 
59   // lowest 3 bits of fsType are exclusive.
60   if (os2->type & 0x2) {
61     // mask bits 2 & 3.
62     os2->type &= 0xfff3u;
63   } else if (os2->type & 0x4) {
64     // mask bits 1 & 3.
65     os2->type &= 0xfff4u;
66   } else if (os2->type & 0x8) {
67     // mask bits 1 & 2.
68     os2->type &= 0xfff9u;
69   }
70 
71   // mask reserved bits. use only 0..3, 8, 9 bits.
72   os2->type &= 0x30f;
73 
74   if (os2->subscript_x_size < 0) {
75     OTS_WARNING("bad subscript_x_size: %d", os2->subscript_x_size);
76     os2->subscript_x_size = 0;
77   }
78   if (os2->subscript_y_size < 0) {
79     OTS_WARNING("bad subscript_y_size: %d", os2->subscript_y_size);
80     os2->subscript_y_size = 0;
81   }
82   if (os2->superscript_x_size < 0) {
83     OTS_WARNING("bad superscript_x_size: %d", os2->superscript_x_size);
84     os2->superscript_x_size = 0;
85   }
86   if (os2->superscript_y_size < 0) {
87     OTS_WARNING("bad superscript_y_size: %d", os2->superscript_y_size);
88     os2->superscript_y_size = 0;
89   }
90   if (os2->strikeout_size < 0) {
91     OTS_WARNING("bad strikeout_size: %d", os2->strikeout_size);
92     os2->strikeout_size = 0;
93   }
94 
95   for (unsigned i = 0; i < 10; ++i) {
96     if (!table.ReadU8(&os2->panose[i])) {
97       return OTS_FAILURE();
98     }
99   }
100 
101   if (!table.ReadU32(&os2->unicode_range_1) ||
102       !table.ReadU32(&os2->unicode_range_2) ||
103       !table.ReadU32(&os2->unicode_range_3) ||
104       !table.ReadU32(&os2->unicode_range_4) ||
105       !table.ReadU32(&os2->vendor_id) ||
106       !table.ReadU16(&os2->selection) ||
107       !table.ReadU16(&os2->first_char_index) ||
108       !table.ReadU16(&os2->last_char_index) ||
109       !table.ReadS16(&os2->typo_ascender) ||
110       !table.ReadS16(&os2->typo_descender) ||
111       !table.ReadS16(&os2->typo_linegap) ||
112       !table.ReadU16(&os2->win_ascent) ||
113       !table.ReadU16(&os2->win_descent)) {
114     return OTS_FAILURE();
115   }
116 
117   // If bit 6 is set, then bits 0 and 5 must be clear.
118   if (os2->selection & 0x40) {
119     os2->selection &= 0xffdeu;
120   }
121 
122   // the settings of bits 0 and 1 must be reflected in the macStyle bits
123   // in the 'head' table.
124   if (!file->head) {
125     return OTS_FAILURE();
126   }
127   if ((os2->selection & 0x1) &&
128       !(file->head->mac_style & 0x2)) {
129     OTS_WARNING("adjusting Mac style (italic)");
130     file->head->mac_style |= 0x2;
131   }
132   if ((os2->selection & 0x2) &&
133       !(file->head->mac_style & 0x4)) {
134     OTS_WARNING("adjusting Mac style (underscore)");
135     file->head->mac_style |= 0x4;
136   }
137 
138   // While bit 6 on implies that bits 0 and 1 of macStyle are clear,
139   // the reverse is not true.
140   if ((os2->selection & 0x40) &&
141       (file->head->mac_style & 0x3)) {
142     OTS_WARNING("adjusting Mac style (regular)");
143     file->head->mac_style &= 0xfffcu;
144   }
145 
146   if ((os2->version < 4) &&
147       (os2->selection & 0x300)) {
148     // bit 8 and 9 must be unset in OS/2 table versions less than 4.
149     return OTS_FAILURE();
150   }
151 
152   // mask reserved bits. use only 0..9 bits.
153   os2->selection &= 0x3ff;
154 
155   if (os2->first_char_index > os2->last_char_index) {
156     return OTS_FAILURE();
157   }
158   if (os2->typo_linegap < 0) {
159     OTS_WARNING("bad linegap: %d", os2->typo_linegap);
160     os2->typo_linegap = 0;
161   }
162 
163   if (os2->version < 1) {
164     // http://www.microsoft.com/typography/otspec/os2ver0.htm
165     return true;
166   }
167 
168   if (length < offsetof(OpenTypeOS2, code_page_range_2)) {
169     OTS_WARNING("bad version number: %u", os2->version);
170     // Some fonts (e.g., kredit1.ttf and quinquef.ttf) have weird version
171     // numbers. Fix them.
172     os2->version = 0;
173     return true;
174   }
175 
176   if (!table.ReadU32(&os2->code_page_range_1) ||
177       !table.ReadU32(&os2->code_page_range_2)) {
178     return OTS_FAILURE();
179   }
180 
181   if (os2->version < 2) {
182     // http://www.microsoft.com/typography/otspec/os2ver1.htm
183     return true;
184   }
185 
186   if (length < offsetof(OpenTypeOS2, max_context)) {
187     OTS_WARNING("bad version number: %u", os2->version);
188     // some Japanese fonts (e.g., mona.ttf) have weird version number.
189     // fix them.
190     os2->version = 1;
191     return true;
192   }
193 
194   if (!table.ReadS16(&os2->x_height) ||
195       !table.ReadS16(&os2->cap_height) ||
196       !table.ReadU16(&os2->default_char) ||
197       !table.ReadU16(&os2->break_char) ||
198       !table.ReadU16(&os2->max_context)) {
199     return OTS_FAILURE();
200   }
201 
202   if (os2->x_height < 0) {
203     OTS_WARNING("bad x_height: %d", os2->x_height);
204     os2->x_height = 0;
205   }
206   if (os2->cap_height < 0) {
207     OTS_WARNING("bad cap_height: %d", os2->cap_height);
208     os2->cap_height = 0;
209   }
210 
211   return true;
212 }
213 
ots_os2_should_serialise(OpenTypeFile * file)214 bool ots_os2_should_serialise(OpenTypeFile *file) {
215   return file->os2 != NULL;
216 }
217 
ots_os2_serialise(OTSStream * out,OpenTypeFile * file)218 bool ots_os2_serialise(OTSStream *out, OpenTypeFile *file) {
219   const OpenTypeOS2 *os2 = file->os2;
220 
221   if (!out->WriteU16(os2->version) ||
222       !out->WriteS16(os2->avg_char_width) ||
223       !out->WriteU16(os2->weight_class) ||
224       !out->WriteU16(os2->width_class) ||
225       !out->WriteU16(os2->type) ||
226       !out->WriteS16(os2->subscript_x_size) ||
227       !out->WriteS16(os2->subscript_y_size) ||
228       !out->WriteS16(os2->subscript_x_offset) ||
229       !out->WriteS16(os2->subscript_y_offset) ||
230       !out->WriteS16(os2->superscript_x_size) ||
231       !out->WriteS16(os2->superscript_y_size) ||
232       !out->WriteS16(os2->superscript_x_offset) ||
233       !out->WriteS16(os2->superscript_y_offset) ||
234       !out->WriteS16(os2->strikeout_size) ||
235       !out->WriteS16(os2->strikeout_position) ||
236       !out->WriteS16(os2->family_class)) {
237     return OTS_FAILURE();
238   }
239 
240   for (unsigned i = 0; i < 10; ++i) {
241     if (!out->Write(&os2->panose[i], 1)) {
242       return OTS_FAILURE();
243     }
244   }
245 
246   if (!out->WriteU32(os2->unicode_range_1) ||
247       !out->WriteU32(os2->unicode_range_2) ||
248       !out->WriteU32(os2->unicode_range_3) ||
249       !out->WriteU32(os2->unicode_range_4) ||
250       !out->WriteU32(os2->vendor_id) ||
251       !out->WriteU16(os2->selection) ||
252       !out->WriteU16(os2->first_char_index) ||
253       !out->WriteU16(os2->last_char_index) ||
254       !out->WriteS16(os2->typo_ascender) ||
255       !out->WriteS16(os2->typo_descender) ||
256       !out->WriteS16(os2->typo_linegap) ||
257       !out->WriteU16(os2->win_ascent) ||
258       !out->WriteU16(os2->win_descent)) {
259     return OTS_FAILURE();
260   }
261 
262   if (os2->version < 1) {
263     return true;
264   }
265 
266   if (!out->WriteU32(os2->code_page_range_1) ||
267       !out->WriteU32(os2->code_page_range_2)) {
268     return OTS_FAILURE();
269   }
270 
271   if (os2->version < 2) {
272     return true;
273   }
274 
275   if (!out->WriteS16(os2->x_height) ||
276       !out->WriteS16(os2->cap_height) ||
277       !out->WriteU16(os2->default_char) ||
278       !out->WriteU16(os2->break_char) ||
279       !out->WriteU16(os2->max_context)) {
280     return OTS_FAILURE();
281   }
282 
283   return true;
284 }
285 
ots_os2_free(OpenTypeFile * file)286 void ots_os2_free(OpenTypeFile *file) {
287   delete file->os2;
288 }
289 
290 }  // namespace ots
291