1 // Copyright (c) 2009-2017 The OTS 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 <string>
6 
7 #include "os2.h"
8 #include "head.h"
9 
10 // OS/2 - OS/2 and Windows Metrics
11 // http://www.microsoft.com/typography/otspec/os2.htm
12 
13 namespace ots {
14 
Parse(const uint8_t * data,size_t length)15 bool OpenTypeOS2::Parse(const uint8_t *data, size_t length) {
16   Buffer table(data, length);
17 
18   if (!table.ReadU16(&this->table.version) ||
19       !table.ReadS16(&this->table.avg_char_width) ||
20       !table.ReadU16(&this->table.weight_class) ||
21       !table.ReadU16(&this->table.width_class) ||
22       !table.ReadU16(&this->table.type) ||
23       !table.ReadS16(&this->table.subscript_x_size) ||
24       !table.ReadS16(&this->table.subscript_y_size) ||
25       !table.ReadS16(&this->table.subscript_x_offset) ||
26       !table.ReadS16(&this->table.subscript_y_offset) ||
27       !table.ReadS16(&this->table.superscript_x_size) ||
28       !table.ReadS16(&this->table.superscript_y_size) ||
29       !table.ReadS16(&this->table.superscript_x_offset) ||
30       !table.ReadS16(&this->table.superscript_y_offset) ||
31       !table.ReadS16(&this->table.strikeout_size) ||
32       !table.ReadS16(&this->table.strikeout_position) ||
33       !table.ReadS16(&this->table.family_class)) {
34     return Error("Error reading basic table elements");
35   }
36 
37   if (this->table.version > 5) {
38     return Error("Unsupported table version: %u", this->table.version);
39   }
40 
41   // Follow WPF Font Selection Model's advice.
42   if (1 <= this->table.weight_class && this->table.weight_class <= 9) {
43     Warning("Bad usWeightClass: %u, changing it to %u",
44             this->table.weight_class, this->table.weight_class * 100);
45     this->table.weight_class *= 100;
46   }
47   // Ditto.
48   if (this->table.weight_class > 999) {
49     Warning("Bad usWeightClass: %u, changing it to %d",
50              this->table.weight_class, 999);
51     this->table.weight_class = 999;
52   }
53 
54   if (this->table.width_class < 1) {
55     Warning("Bad usWidthClass: %u, changing it to %d",
56             this->table.width_class, 1);
57     this->table.width_class = 1;
58   } else if (this->table.width_class > 9) {
59     Warning("Bad usWidthClass: %u, changing it to %d",
60             this->table.width_class, 9);
61     this->table.width_class = 9;
62   }
63 
64   // lowest 3 bits of fsType are exclusive.
65   if (this->table.type & 0x2) {
66     // mask bits 2 & 3.
67     this->table.type &= 0xfff3u;
68   } else if (this->table.type & 0x4) {
69     // mask bits 1 & 3.
70     this->table.type &= 0xfff4u;
71   } else if (this->table.type & 0x8) {
72     // mask bits 1 & 2.
73     this->table.type &= 0xfff9u;
74   }
75 
76   // mask reserved bits. use only 0..3, 8, 9 bits.
77   this->table.type &= 0x30f;
78 
79 #define SET_TO_ZERO(a, b)                                                      \
80   if (this->table.b < 0) {                                                     \
81     Warning("Bad " a ": %d, setting it to zero", this->table.b);               \
82     this->table.b = 0;                                                         \
83   }
84 
85   SET_TO_ZERO("ySubscriptXSize", subscript_x_size);
86   SET_TO_ZERO("ySubscriptYSize", subscript_y_size);
87   SET_TO_ZERO("ySuperscriptXSize", superscript_x_size);
88   SET_TO_ZERO("ySuperscriptYSize", superscript_y_size);
89   SET_TO_ZERO("yStrikeoutSize", strikeout_size);
90 #undef SET_TO_ZERO
91 
92   static std::string panose_strings[10] = {
93     "bFamilyType",
94     "bSerifStyle",
95     "bWeight",
96     "bProportion",
97     "bContrast",
98     "bStrokeVariation",
99     "bArmStyle",
100     "bLetterform",
101     "bMidline",
102     "bXHeight",
103   };
104   for (unsigned i = 0; i < 10; ++i) {
105     if (!table.ReadU8(&this->table.panose[i])) {
106       return Error("Failed to read PANOSE %s", panose_strings[i].c_str());
107     }
108   }
109 
110   if (!table.ReadU32(&this->table.unicode_range_1) ||
111       !table.ReadU32(&this->table.unicode_range_2) ||
112       !table.ReadU32(&this->table.unicode_range_3) ||
113       !table.ReadU32(&this->table.unicode_range_4) ||
114       !table.ReadU32(&this->table.vendor_id) ||
115       !table.ReadU16(&this->table.selection) ||
116       !table.ReadU16(&this->table.first_char_index) ||
117       !table.ReadU16(&this->table.last_char_index) ||
118       !table.ReadS16(&this->table.typo_ascender) ||
119       !table.ReadS16(&this->table.typo_descender) ||
120       !table.ReadS16(&this->table.typo_linegap) ||
121       !table.ReadU16(&this->table.win_ascent) ||
122       !table.ReadU16(&this->table.win_descent)) {
123     return Error("Error reading more basic table fields");
124   }
125 
126   // If bit 6 is set, then bits 0 and 5 must be clear.
127   if (this->table.selection & 0x40) {
128     this->table.selection &= 0xffdeu;
129   }
130 
131   // the settings of bits 0 and 1 must be reflected in the macStyle bits
132   // in the 'head' table.
133   OpenTypeHEAD *head = static_cast<OpenTypeHEAD*>(
134       GetFont()->GetTypedTable(OTS_TAG_HEAD));
135 
136   if ((this->table.selection & 0x1) &&
137       head && !(head->mac_style & 0x2)) {
138     Warning("Adjusting head.macStyle (italic) to match fsSelection");
139     head->mac_style |= 0x2;
140   }
141   if ((this->table.selection & 0x2) &&
142       head && !(head->mac_style & 0x4)) {
143     Warning("Adjusting head.macStyle (underscore) to match fsSelection");
144     head->mac_style |= 0x4;
145   }
146 
147   // While bit 6 on implies that bits 0 and 1 of macStyle are clear,
148   // the reverse is not true.
149   if ((this->table.selection & 0x40) &&
150       head && (head->mac_style & 0x3)) {
151     Warning("Adjusting head.macStyle (regular) to match fsSelection");
152     head->mac_style &= 0xfffcu;
153   }
154 
155   if ((this->table.version < 4) &&
156       (this->table.selection & 0x300)) {
157     // bit 8 and 9 must be unset in OS/2 table versions less than 4.
158     return Error("fSelection bits 8 and 9 must be unset for table version %d",
159                  this->table.version);
160   }
161 
162   // mask reserved bits. use only 0..9 bits.
163   this->table.selection &= 0x3ff;
164 
165   if (this->table.first_char_index > this->table.last_char_index) {
166     return Error("usFirstCharIndex %d > usLastCharIndex %d",
167                  this->table.first_char_index, this->table.last_char_index);
168   }
169   if (this->table.typo_linegap < 0) {
170     Warning("Bad sTypoLineGap, setting it to 0: %d", this->table.typo_linegap);
171     this->table.typo_linegap = 0;
172   }
173 
174   if (this->table.version < 1) {
175     // http://www.microsoft.com/typography/otspec/os2ver0.htm
176     return true;
177   }
178 
179   if (length < offsetof(OS2Data, code_page_range_2)) {
180     Warning("Bad version number, setting it to 0: %u", this->table.version);
181     // Some fonts (e.g., kredit1.ttf and quinquef.ttf) have weird version
182     // numbers. Fix them.
183     this->table.version = 0;
184     return true;
185   }
186 
187   if (!table.ReadU32(&this->table.code_page_range_1) ||
188       !table.ReadU32(&this->table.code_page_range_2)) {
189     return Error("Failed to read ulCodePageRange1 or ulCodePageRange2");
190   }
191 
192   if (this->table.version < 2) {
193     // http://www.microsoft.com/typography/otspec/os2ver1.htm
194     return true;
195   }
196 
197   if (length < offsetof(OS2Data, max_context)) {
198     Warning("Bad version number, setting it to 1: %u", this->table.version);
199     // some Japanese fonts (e.g., mona.ttf) have weird version number.
200     // fix them.
201     this->table.version = 1;
202     return true;
203   }
204 
205   if (!table.ReadS16(&this->table.x_height) ||
206       !table.ReadS16(&this->table.cap_height) ||
207       !table.ReadU16(&this->table.default_char) ||
208       !table.ReadU16(&this->table.break_char) ||
209       !table.ReadU16(&this->table.max_context)) {
210     return Error("Failed to read version 2-specific fields");
211   }
212 
213   if (this->table.x_height < 0) {
214     Warning("Bad sxHeight settig it to 0: %d", this->table.x_height);
215     this->table.x_height = 0;
216   }
217   if (this->table.cap_height < 0) {
218     Warning("Bad sCapHeight setting it to 0: %d", this->table.cap_height);
219     this->table.cap_height = 0;
220   }
221 
222   if (this->table.version < 5) {
223     // http://www.microsoft.com/typography/otspec/os2ver4.htm
224     return true;
225   }
226 
227   if (!table.ReadU16(&this->table.lower_optical_pointsize) ||
228       !table.ReadU16(&this->table.upper_optical_pointsize)) {
229     return Error("Failed to read version 5-specific fields");
230   }
231 
232   if (this->table.lower_optical_pointsize > 0xFFFE) {
233     Warning("usLowerOpticalPointSize is bigger than 0xFFFE: %d",
234             this->table.lower_optical_pointsize);
235     this->table.lower_optical_pointsize = 0xFFFE;
236   }
237 
238   if (this->table.upper_optical_pointsize < 2) {
239     Warning("usUpperOpticalPointSize is lower than 2: %d",
240             this->table.upper_optical_pointsize);
241     this->table.upper_optical_pointsize = 2;
242   }
243 
244   return true;
245 }
246 
Serialize(OTSStream * out)247 bool OpenTypeOS2::Serialize(OTSStream *out) {
248   if (!out->WriteU16(this->table.version) ||
249       !out->WriteS16(this->table.avg_char_width) ||
250       !out->WriteU16(this->table.weight_class) ||
251       !out->WriteU16(this->table.width_class) ||
252       !out->WriteU16(this->table.type) ||
253       !out->WriteS16(this->table.subscript_x_size) ||
254       !out->WriteS16(this->table.subscript_y_size) ||
255       !out->WriteS16(this->table.subscript_x_offset) ||
256       !out->WriteS16(this->table.subscript_y_offset) ||
257       !out->WriteS16(this->table.superscript_x_size) ||
258       !out->WriteS16(this->table.superscript_y_size) ||
259       !out->WriteS16(this->table.superscript_x_offset) ||
260       !out->WriteS16(this->table.superscript_y_offset) ||
261       !out->WriteS16(this->table.strikeout_size) ||
262       !out->WriteS16(this->table.strikeout_position) ||
263       !out->WriteS16(this->table.family_class)) {
264     return Error("Failed to write basic table data");
265   }
266 
267   for (unsigned i = 0; i < 10; ++i) {
268     if (!out->Write(&this->table.panose[i], 1)) {
269       return Error("Failed to write PANOSE data");
270     }
271   }
272 
273   if (!out->WriteU32(this->table.unicode_range_1) ||
274       !out->WriteU32(this->table.unicode_range_2) ||
275       !out->WriteU32(this->table.unicode_range_3) ||
276       !out->WriteU32(this->table.unicode_range_4) ||
277       !out->WriteU32(this->table.vendor_id) ||
278       !out->WriteU16(this->table.selection) ||
279       !out->WriteU16(this->table.first_char_index) ||
280       !out->WriteU16(this->table.last_char_index) ||
281       !out->WriteS16(this->table.typo_ascender) ||
282       !out->WriteS16(this->table.typo_descender) ||
283       !out->WriteS16(this->table.typo_linegap) ||
284       !out->WriteU16(this->table.win_ascent) ||
285       !out->WriteU16(this->table.win_descent)) {
286     return Error("Failed to write version 1-specific fields");
287   }
288 
289   if (this->table.version < 1) {
290     return true;
291   }
292 
293   if (!out->WriteU32(this->table.code_page_range_1) ||
294       !out->WriteU32(this->table.code_page_range_2)) {
295     return Error("Failed to write codepage ranges");
296   }
297 
298   if (this->table.version < 2) {
299     return true;
300   }
301 
302   if (!out->WriteS16(this->table.x_height) ||
303       !out->WriteS16(this->table.cap_height) ||
304       !out->WriteU16(this->table.default_char) ||
305       !out->WriteU16(this->table.break_char) ||
306       !out->WriteU16(this->table.max_context)) {
307     return Error("Failed to write version 2-specific fields");
308   }
309 
310   if (this->table.version < 5) {
311     return true;
312   }
313 
314   if (!out->WriteU16(this->table.lower_optical_pointsize) ||
315       !out->WriteU16(this->table.upper_optical_pointsize)) {
316     return Error("Failed to write version 5-specific fields");
317   }
318 
319   return true;
320 }
321 
322 }  // namespace ots
323