core/fxge/freetype/fx_freetype.cpp

// Copyright 2014 The PDFium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com

#include "core/fxge/freetype/fx_freetype.h"

#include <stdint.h>

#define DEFINE_PS_TABLES
#include "third_party/freetype/include/pstables.h"

namespace {

constexpr uint32_t kVariantBit = 0x80000000;

int xyq_search_node(char* glyph_name,
                    int name_offset,
                    int table_offset,
                    wchar_t unicode) {
  // copy letters
  while (true) {
    glyph_name[name_offset] = ft_adobe_glyph_list[table_offset] & 0x7f;
    name_offset++;
    table_offset++;
    if (!(ft_adobe_glyph_list[table_offset - 1] & 0x80))
      break;
  }
  glyph_name[name_offset] = 0;

  // get child count
  int count = ft_adobe_glyph_list[table_offset] & 0x7f;

  // check if we have value for this node
  if (ft_adobe_glyph_list[table_offset] & 0x80) {
    unsigned short thiscode = ft_adobe_glyph_list[table_offset + 1] * 256 +
                              ft_adobe_glyph_list[table_offset + 2];
    if (thiscode == (unsigned short)unicode)  // found it!
      return 1;
    table_offset += 3;
  } else {
    table_offset++;
  }

  // now search in sub-nodes
  if (count == 0)
    return 0;

  for (int i = 0; i < count; i++) {
    int child_offset = ft_adobe_glyph_list[table_offset + i * 2] * 256 +
                       ft_adobe_glyph_list[table_offset + i * 2 + 1];
    if (xyq_search_node(glyph_name, name_offset, child_offset, unicode))
      // found in child
      return 1;
  }
  return 0;
}

}  // namespace

int FXFT_unicode_from_adobe_name(const char* glyph_name) {
  /* If the name begins with `uni', then the glyph name may be a */
  /* hard-coded unicode character code.                          */
  if (glyph_name[0] == 'u' && glyph_name[1] == 'n' && glyph_name[2] == 'i') {
    /* determine whether the next four characters following are */
    /* hexadecimal.                                             */

    /* XXX: Add code to deal with ligatures, i.e. glyph names like */
    /*      `uniXXXXYYYYZZZZ'...                                   */

    FT_Int count;
    FT_UInt32 value = 0;
    const char* p = glyph_name + 3;

    for (count = 4; count > 0; count--, p++) {
      char c = *p;
      unsigned int d = (unsigned char)c - '0';
      if (d >= 10) {
        d = (unsigned char)c - 'A';
        if (d >= 6)
          d = 16;
        else
          d += 10;
      }

      /* Exit if a non-uppercase hexadecimal character was found   */
      /* -- this also catches character codes below `0' since such */
      /* negative numbers cast to `unsigned int' are far too big.  */
      if (d >= 16)
        break;

      value = (value << 4) + d;
    }

    /* there must be exactly four hex digits */
    if (count == 0) {
      if (*p == '\0')
        return value;
      if (*p == '.')
        return (FT_UInt32)(value | kVariantBit);
    }
  }

  /* If the name begins with `u', followed by four to six uppercase */
  /* hexadecimal digits, it is a hard-coded unicode character code. */
  if (glyph_name[0] == 'u') {
    FT_Int count;
    FT_UInt32 value = 0;
    const char* p = glyph_name + 1;

    for (count = 6; count > 0; count--, p++) {
      char c = *p;
      unsigned int d = (unsigned char)c - '0';
      if (d >= 10) {
        d = (unsigned char)c - 'A';
        if (d >= 6)
          d = 16;
        else
          d += 10;
      }

      if (d >= 16)
        break;

      value = (value << 4) + d;
    }

    if (count <= 2) {
      if (*p == '\0')
        return value;
      if (*p == '.')
        return (FT_UInt32)(value | kVariantBit);
    }
  }

  /* Look for a non-initial dot in the glyph name in order to */
  /* find variants like `A.swash', `e.final', etc.            */
  {
    const char* p = glyph_name;
    const char* dot = nullptr;

    for (; *p; p++) {
      if (*p == '.' && p > glyph_name) {
        dot = p;
        break;
      }
    }

    /* now look up the glyph in the Adobe Glyph List */
    if (!dot)
      return (FT_UInt32)ft_get_adobe_glyph_index(glyph_name, p);

    return (FT_UInt32)(ft_get_adobe_glyph_index(glyph_name, dot) | kVariantBit);
  }
}

void FXFT_adobe_name_from_unicode(char* glyph_name, wchar_t unicode) {
  // start from top level node
  int count = ft_adobe_glyph_list[1];
  for (int i = 0; i < count; i++) {
    int child_offset =
        ft_adobe_glyph_list[i * 2 + 2] * 256 + ft_adobe_glyph_list[i * 2 + 3];
    if (xyq_search_node(glyph_name, 0, child_offset, unicode))
      return;
  }

  // failed, clear the buffer
  glyph_name[0] = 0;
}