tor-browser

os2.cc (11106B)

---

// Copyright (c) 2009-2017 The OTS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <string>

#include "os2.h"
#include "head.h"

// OS/2 - OS/2 and Windows Metrics
// http://www.microsoft.com/typography/otspec/os2.htm

namespace ots {

bool OpenTypeOS2::Parse(const uint8_t *data, size_t length) {
 Buffer table(data, length);

 if (!table.ReadU16(&this->table.version) ||
     !table.ReadS16(&this->table.avg_char_width) ||
     !table.ReadU16(&this->table.weight_class) ||
     !table.ReadU16(&this->table.width_class) ||
     !table.ReadU16(&this->table.type) ||
     !table.ReadS16(&this->table.subscript_x_size) ||
     !table.ReadS16(&this->table.subscript_y_size) ||
     !table.ReadS16(&this->table.subscript_x_offset) ||
     !table.ReadS16(&this->table.subscript_y_offset) ||
     !table.ReadS16(&this->table.superscript_x_size) ||
     !table.ReadS16(&this->table.superscript_y_size) ||
     !table.ReadS16(&this->table.superscript_x_offset) ||
     !table.ReadS16(&this->table.superscript_y_offset) ||
     !table.ReadS16(&this->table.strikeout_size) ||
     !table.ReadS16(&this->table.strikeout_position) ||
     !table.ReadS16(&this->table.family_class)) {
   return Error("Error reading basic table elements");
 }

 if (this->table.version > 5) {
   return Error("Unsupported table version: %u", this->table.version);
 }

 if (this->table.weight_class < 1) {
   Warning("Bad usWeightClass: %u, changing it to %d",
            this->table.weight_class, 1);
   this->table.weight_class = 1;
 } else if (this->table.weight_class > 1000) {
   Warning("Bad usWeightClass: %u, changing it to %d",
            this->table.weight_class, 1000);
   this->table.weight_class = 1000;
 }

 if (this->table.width_class < 1) {
   Warning("Bad usWidthClass: %u, changing it to %d",
           this->table.width_class, 1);
   this->table.width_class = 1;
 } else if (this->table.width_class > 9) {
   Warning("Bad usWidthClass: %u, changing it to %d",
           this->table.width_class, 9);
   this->table.width_class = 9;
 }

 // lowest 3 bits of fsType are exclusive.
 if (this->table.type & 0x2) {
   // mask bits 2 & 3.
   this->table.type &= 0xfff3u;
 } else if (this->table.type & 0x4) {
   // mask bits 1 & 3.
   this->table.type &= 0xfff4u;
 } else if (this->table.type & 0x8) {
   // mask bits 1 & 2.
   this->table.type &= 0xfff9u;
 }

 // mask reserved bits. use only 0..3, 8, 9 bits.
 this->table.type &= 0x30f;

#define SET_TO_ZERO(a, b)                                                      \
 if (this->table.b < 0) {                                                     \
   Warning("Bad " a ": %d, setting it to zero", this->table.b);               \
   this->table.b = 0;                                                         \
 }

 SET_TO_ZERO("ySubscriptXSize", subscript_x_size);
 SET_TO_ZERO("ySubscriptYSize", subscript_y_size);
 SET_TO_ZERO("ySuperscriptXSize", superscript_x_size);
 SET_TO_ZERO("ySuperscriptYSize", superscript_y_size);
 SET_TO_ZERO("yStrikeoutSize", strikeout_size);
#undef SET_TO_ZERO

 static const char* panose_strings[10] = {
   "bFamilyType",
   "bSerifStyle",
   "bWeight",
   "bProportion",
   "bContrast",
   "bStrokeVariation",
   "bArmStyle",
   "bLetterform",
   "bMidline",
   "bXHeight",
 };
 for (unsigned i = 0; i < 10; ++i) {
   if (!table.ReadU8(&this->table.panose[i])) {
     return Error("Failed to read PANOSE %s", panose_strings[i]);
   }
 }

 if (!table.ReadU32(&this->table.unicode_range_1) ||
     !table.ReadU32(&this->table.unicode_range_2) ||
     !table.ReadU32(&this->table.unicode_range_3) ||
     !table.ReadU32(&this->table.unicode_range_4) ||
     !table.ReadU32(&this->table.vendor_id) ||
     !table.ReadU16(&this->table.selection) ||
     !table.ReadU16(&this->table.first_char_index) ||
     !table.ReadU16(&this->table.last_char_index) ||
     !table.ReadS16(&this->table.typo_ascender) ||
     !table.ReadS16(&this->table.typo_descender) ||
     !table.ReadS16(&this->table.typo_linegap) ||
     !table.ReadU16(&this->table.win_ascent) ||
     !table.ReadU16(&this->table.win_descent)) {
   return Error("Error reading more basic table fields");
 }

 // If bit 6 is set, then bits 0 and 5 must be clear.
 if (this->table.selection & 0x40) {
   this->table.selection &= 0xffdeu;
 }

 // the settings of bits 0 and 1 must be reflected in the macStyle bits
 // in the 'head' table.
 OpenTypeHEAD *head = static_cast<OpenTypeHEAD*>(
     GetFont()->GetTypedTable(OTS_TAG_HEAD));

 if ((this->table.selection & 0x1) &&
     head && !(head->mac_style & 0x2)) {
   Warning("Adjusting head.macStyle (italic) to match fsSelection");
   head->mac_style |= 0x2;
 }
 if ((this->table.selection & 0x2) &&
     head && !(head->mac_style & 0x4)) {
   Warning("Adjusting head.macStyle (underscore) to match fsSelection");
   head->mac_style |= 0x4;
 }

 // While bit 6 on implies that bits 0 and 1 of macStyle are clear,
 // the reverse is not true.
 if ((this->table.selection & 0x40) &&
     head && (head->mac_style & 0x3)) {
   Warning("Adjusting head.macStyle (regular) to match fsSelection");
   head->mac_style &= 0xfffcu;
 }

 if ((this->table.version < 4) &&
     (this->table.selection & 0x300)) {
   // bit 8 and 9 must be unset in OS/2 table versions less than 4.
   Warning("fsSelection bits 8 and 9 must be unset for table version %d",
           this->table.version);
 }

 // mask reserved bits. use only 0..9 bits.
 this->table.selection &= 0x3ff;

 if (this->table.first_char_index > this->table.last_char_index) {
   Warning("usFirstCharIndex %d > usLastCharIndex %d",
           this->table.first_char_index, this->table.last_char_index);
   this->table.first_char_index = this->table.last_char_index;
 }
 if (this->table.typo_linegap < 0) {
   Warning("Bad sTypoLineGap, setting it to 0: %d", this->table.typo_linegap);
   this->table.typo_linegap = 0;
 }

 if (this->table.version < 1) {
   // http://www.microsoft.com/typography/otspec/os2ver0.htm
   return true;
 }

 if (length < offsetof(OS2Data, code_page_range_2)) {
   Warning("Bad version number, setting it to 0: %u", this->table.version);
   // Some fonts (e.g., kredit1.ttf and quinquef.ttf) have weird version
   // numbers. Fix them.
   this->table.version = 0;
   return true;
 }

 if (!table.ReadU32(&this->table.code_page_range_1) ||
     !table.ReadU32(&this->table.code_page_range_2)) {
   return Error("Failed to read ulCodePageRange1 or ulCodePageRange2");
 }

 if (this->table.version < 2) {
   // http://www.microsoft.com/typography/otspec/os2ver1.htm
   return true;
 }

 if (length < offsetof(OS2Data, max_context)) {
   Warning("Bad version number, setting it to 1: %u", this->table.version);
   // some Japanese fonts (e.g., mona.ttf) have weird version number.
   // fix them.
   this->table.version = 1;
   return true;
 }

 if (!table.ReadS16(&this->table.x_height) ||
     !table.ReadS16(&this->table.cap_height) ||
     !table.ReadU16(&this->table.default_char) ||
     !table.ReadU16(&this->table.break_char) ||
     !table.ReadU16(&this->table.max_context)) {
   return Error("Failed to read version 2-specific fields");
 }

 if (this->table.x_height < 0) {
   Warning("Bad sxHeight setting it to 0: %d", this->table.x_height);
   this->table.x_height = 0;
 }
 if (this->table.cap_height < 0) {
   Warning("Bad sCapHeight setting it to 0: %d", this->table.cap_height);
   this->table.cap_height = 0;
 }

 if (this->table.version < 5) {
   // http://www.microsoft.com/typography/otspec/os2ver4.htm
   return true;
 }

 if (!table.ReadU16(&this->table.lower_optical_pointsize) ||
     !table.ReadU16(&this->table.upper_optical_pointsize)) {
   return Error("Failed to read version 5-specific fields");
 }

 if (this->table.lower_optical_pointsize > 0xFFFE) {
   Warning("usLowerOpticalPointSize is bigger than 0xFFFE: %d",
           this->table.lower_optical_pointsize);
   this->table.lower_optical_pointsize = 0xFFFE;
 }

 if (this->table.upper_optical_pointsize < 2) {
   Warning("usUpperOpticalPointSize is lower than 2: %d",
           this->table.upper_optical_pointsize);
   this->table.upper_optical_pointsize = 2;
 }

 return true;
}

bool OpenTypeOS2::Serialize(OTSStream *out) {
 if (!out->WriteU16(this->table.version) ||
     !out->WriteS16(this->table.avg_char_width) ||
     !out->WriteU16(this->table.weight_class) ||
     !out->WriteU16(this->table.width_class) ||
     !out->WriteU16(this->table.type) ||
     !out->WriteS16(this->table.subscript_x_size) ||
     !out->WriteS16(this->table.subscript_y_size) ||
     !out->WriteS16(this->table.subscript_x_offset) ||
     !out->WriteS16(this->table.subscript_y_offset) ||
     !out->WriteS16(this->table.superscript_x_size) ||
     !out->WriteS16(this->table.superscript_y_size) ||
     !out->WriteS16(this->table.superscript_x_offset) ||
     !out->WriteS16(this->table.superscript_y_offset) ||
     !out->WriteS16(this->table.strikeout_size) ||
     !out->WriteS16(this->table.strikeout_position) ||
     !out->WriteS16(this->table.family_class)) {
   return Error("Failed to write basic table data");
 }

 for (unsigned i = 0; i < 10; ++i) {
   if (!out->Write(&this->table.panose[i], 1)) {
     return Error("Failed to write PANOSE data");
   }
 }

 if (!out->WriteU32(this->table.unicode_range_1) ||
     !out->WriteU32(this->table.unicode_range_2) ||
     !out->WriteU32(this->table.unicode_range_3) ||
     !out->WriteU32(this->table.unicode_range_4) ||
     !out->WriteU32(this->table.vendor_id) ||
     !out->WriteU16(this->table.selection) ||
     !out->WriteU16(this->table.first_char_index) ||
     !out->WriteU16(this->table.last_char_index) ||
     !out->WriteS16(this->table.typo_ascender) ||
     !out->WriteS16(this->table.typo_descender) ||
     !out->WriteS16(this->table.typo_linegap) ||
     !out->WriteU16(this->table.win_ascent) ||
     !out->WriteU16(this->table.win_descent)) {
   return Error("Failed to write version 1-specific fields");
 }

 if (this->table.version < 1) {
   return true;
 }

 if (!out->WriteU32(this->table.code_page_range_1) ||
     !out->WriteU32(this->table.code_page_range_2)) {
   return Error("Failed to write codepage ranges");
 }

 if (this->table.version < 2) {
   return true;
 }

 if (!out->WriteS16(this->table.x_height) ||
     !out->WriteS16(this->table.cap_height) ||
     !out->WriteU16(this->table.default_char) ||
     !out->WriteU16(this->table.break_char) ||
     !out->WriteU16(this->table.max_context)) {
   return Error("Failed to write version 2-specific fields");
 }

 if (this->table.version < 5) {
   return true;
 }

 if (!out->WriteU16(this->table.lower_optical_pointsize) ||
     !out->WriteU16(this->table.upper_optical_pointsize)) {
   return Error("Failed to write version 5-specific fields");
 }

 return true;
}

}  // namespace ots