The Tor Browser: gfx/ots/src/head.cc@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     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.

     5 #include "head.h"

     7 #include <cstring>

     9 // head - Font Header

    10 // http://www.microsoft.com/typography/otspec/head.htm

    12 #define TABLE_NAME "head"

    14 namespace ots {

    16 bool ots_head_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {

    17   Buffer table(data, length);

    18   file->head = new OpenTypeHEAD;

    20   uint32_t version = 0;

    21   if (!table.ReadU32(&version) ||

    22       !table.ReadU32(&file->head->revision)) {

    23     return OTS_FAILURE_MSG("Failed to read head header");

    24   }

    26   if (version >> 16 != 1) {

    27     return OTS_FAILURE_MSG("Bad head table version of %d", version);

    28   }

    30   // Skip the checksum adjustment

    31   if (!table.Skip(4)) {

    32     return OTS_FAILURE_MSG("Failed to read checksum");

    33   }

    35   uint32_t magic;

    36   if (!table.ReadTag(&magic) ||

    37       std::memcmp(&magic, "\x5F\x0F\x3C\xF5", 4)) {

    38     return OTS_FAILURE_MSG("Failed to read font magic number");

    39   }

    41   if (!table.ReadU16(&file->head->flags)) {

    42     return OTS_FAILURE_MSG("Failed to read head flags");

    43   }

    45   // We allow bits 0..4, 11..13

    46   file->head->flags &= 0x381f;

    48   if (!table.ReadU16(&file->head->ppem)) {

    49     return OTS_FAILURE_MSG("Failed to read pixels per em");

    50   }

    52   // ppem must be in range

    53   if (file->head->ppem < 16 ||

    54       file->head->ppem > 16384) {

    55     return OTS_FAILURE_MSG("Bad ppm of %d", file->head->ppem);

    56   }

    58   // ppem must be a power of two

    59 #if 0

    60   // We don't call ots_failure() for now since lots of TrueType fonts are

    61   // not following this rule. Putting OTS_WARNING here is too noisy.

    62   if ((file->head->ppem - 1) & file->head->ppem) {

    63     return OTS_FAILURE_MSG("ppm not a power of two: %d", file->head->ppem);

    64   }

    65 #endif

    67   if (!table.ReadR64(&file->head->created) ||

    68       !table.ReadR64(&file->head->modified)) {

    69     return OTS_FAILURE_MSG("Can't read font dates");

    70   }

    72   if (!table.ReadS16(&file->head->xmin) ||

    73       !table.ReadS16(&file->head->ymin) ||

    74       !table.ReadS16(&file->head->xmax) ||

    75       !table.ReadS16(&file->head->ymax)) {

    76     return OTS_FAILURE_MSG("Failed to read font bounding box");

    77   }

    79   if (file->head->xmin > file->head->xmax) {

    80     return OTS_FAILURE_MSG("Bad x dimension in the font bounding box (%d, %d)", file->head->xmin, file->head->xmax);

    81   }

    82   if (file->head->ymin > file->head->ymax) {

    83     return OTS_FAILURE_MSG("Bad y dimension in the font bounding box (%d, %d)", file->head->ymin, file->head->ymax);

    84   }

    86   if (!table.ReadU16(&file->head->mac_style)) {

    87     return OTS_FAILURE_MSG("Failed to read font style");

    88   }

    90   // We allow bits 0..6

    91   file->head->mac_style &= 0x7f;

    93   if (!table.ReadU16(&file->head->min_ppem)) {

    94     return OTS_FAILURE_MSG("Failed to read font minimum ppm");

    95   }

    97   // We don't care about the font direction hint

    98   if (!table.Skip(2)) {

    99     return OTS_FAILURE_MSG("Failed to skip font direction hint");

   100   }

   102   if (!table.ReadS16(&file->head->index_to_loc_format)) {

   103     return OTS_FAILURE_MSG("Failed to read index to loc format");

   104   }

   105   if (file->head->index_to_loc_format < 0 ||

   106       file->head->index_to_loc_format > 1) {

   107     return OTS_FAILURE_MSG("Bad index to loc format %d", file->head->index_to_loc_format);

   108   }

   110   int16_t glyph_data_format;

   111   if (!table.ReadS16(&glyph_data_format) ||

   112       glyph_data_format) {

   113     return OTS_FAILURE_MSG("Failed to read glyph data format");

   114   }

   116   return true;

   117 }

   119 bool ots_head_should_serialise(OpenTypeFile *file) {

   120   return file->head != NULL;

   121 }

   123 bool ots_head_serialise(OTSStream *out, OpenTypeFile *file) {

   124   if (!out->WriteU32(0x00010000) ||

   125       !out->WriteU32(file->head->revision) ||

   126       !out->WriteU32(0) ||  // check sum not filled in yet

   127       !out->WriteU32(0x5F0F3CF5) ||

   128       !out->WriteU16(file->head->flags) ||

   129       !out->WriteU16(file->head->ppem) ||

   130       !out->WriteR64(file->head->created) ||

   131       !out->WriteR64(file->head->modified) ||

   132       !out->WriteS16(file->head->xmin) ||

   133       !out->WriteS16(file->head->ymin) ||

   134       !out->WriteS16(file->head->xmax) ||

   135       !out->WriteS16(file->head->ymax) ||

   136       !out->WriteU16(file->head->mac_style) ||

   137       !out->WriteU16(file->head->min_ppem) ||

   138       !out->WriteS16(2) ||

   139       !out->WriteS16(file->head->index_to_loc_format) ||

   140       !out->WriteS16(0)) {

   141     return OTS_FAILURE_MSG("Failed to write head table");

   142   }

   144   return true;

   145 }

   147 void ots_head_free(OpenTypeFile *file) {

   148   delete file->head;

   149 }

   151 }  // namespace

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