The Tor Browser: gfx/ots/src/loca.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 "loca.h"

     7 #include "head.h"

     8 #include "maxp.h"

    10 // loca - Index to Location

    11 // http://www.microsoft.com/typography/otspec/loca.htm

    13 #define TABLE_NAME "loca"

    15 namespace ots {

    17 bool ots_loca_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {

    18   Buffer table(data, length);

    20   // We can't do anything useful in validating this data except to ensure that

    21   // the values are monotonically increasing.

    23   OpenTypeLOCA *loca = new OpenTypeLOCA;

    24   file->loca = loca;

    26   if (!file->maxp || !file->head) {

    27     return OTS_FAILURE_MSG("maxp or head tables missing from font, needed by loca");

    28   }

    30   const unsigned num_glyphs = file->maxp->num_glyphs;

    31   unsigned last_offset = 0;

    32   loca->offsets.resize(num_glyphs + 1);

    33   // maxp->num_glyphs is uint16_t, thus the addition never overflows.

    35   if (file->head->index_to_loc_format == 0) {

    36     // Note that the <= here (and below) is correct. There is one more offset

    37     // than the number of glyphs in order to give the length of the final

    38     // glyph.

    39     for (unsigned i = 0; i <= num_glyphs; ++i) {

    40       uint16_t offset = 0;

    41       if (!table.ReadU16(&offset)) {

    42         return OTS_FAILURE_MSG("Failed to read offset for glyph %d", i);

    43       }

    44       if (offset < last_offset) {

    45         return OTS_FAILURE_MSG("Out of order offset %d < %d for glyph %d", offset, last_offset, i);

    46       }

    47       last_offset = offset;

    48       loca->offsets[i] = offset * 2;

    49     }

    50   } else {

    51     for (unsigned i = 0; i <= num_glyphs; ++i) {

    52       uint32_t offset = 0;

    53       if (!table.ReadU32(&offset)) {

    54         return OTS_FAILURE_MSG("Failed to read offset for glyph %d", i);

    55       }

    56       if (offset < last_offset) {

    57         return OTS_FAILURE_MSG("Out of order offset %d < %d for glyph %d", offset, last_offset, i);

    58       }

    59       last_offset = offset;

    60       loca->offsets[i] = offset;

    61     }

    62   }

    64   return true;

    65 }

    67 bool ots_loca_should_serialise(OpenTypeFile *file) {

    68   return file->loca != NULL;

    69 }

    71 bool ots_loca_serialise(OTSStream *out, OpenTypeFile *file) {

    72   const OpenTypeLOCA *loca = file->loca;

    73   const OpenTypeHEAD *head = file->head;

    75   if (!head) {

    76     return OTS_FAILURE_MSG("Missing head table in font needed by loca");

    77   }

    79   if (head->index_to_loc_format == 0) {

    80     for (unsigned i = 0; i < loca->offsets.size(); ++i) {

    81       if (!out->WriteU16(loca->offsets[i] >> 1)) {

    82         return OTS_FAILURE_MSG("Failed to write glyph offset for glyph %d", i);

    83       }

    84     }

    85   } else {

    86     for (unsigned i = 0; i < loca->offsets.size(); ++i) {

    87       if (!out->WriteU32(loca->offsets[i])) {

    88         return OTS_FAILURE_MSG("Failed to write glyph offset for glyph %d", i);

    89       }

    90     }

    91   }

    93   return true;

    94 }

    96 void ots_loca_free(OpenTypeFile *file) {

    97   delete file->loca;

    98 }

   100 }  // namespace ots

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