text: // Copyright 2016 PDFium Authors. All rights reserved.
  // 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/cfx_unicodeencodingex.h"
  
  #include <memory>
  
  #include "core/fxge/cfx_font.h"
  #include "core/fxge/fx_font.h"
  #include "core/fxge/fx_freetype.h"
  
  #define ENC_TAG(a, b, c, d)                                               \
    (((uint32_t)(a) << 24) | ((uint32_t)(b) << 16) | ((uint32_t)(c) << 8) | \
     (uint32_t)(d))
  
  namespace {
  
  constexpr uint32_t kEncodingExSymbol = ENC_TAG('s', 'y', 'm', 'b');
  constexpr uint32_t kEncodingExUnicode = ENC_TAG('u', 'n', 'i', 'c');
  constexpr uint32_t kEncodingExSjis = ENC_TAG('s', 'j', 'i', 's');
  constexpr uint32_t kEncodingExGB2312 = ENC_TAG('g', 'b', ' ', ' ');
  constexpr uint32_t kEncodingExBig5 = ENC_TAG('b', 'i', 'g', '5');
  constexpr uint32_t kEncodingExWansung = ENC_TAG('w', 'a', 'n', 's');
  constexpr uint32_t kEncodingExJohab = ENC_TAG('j', 'o', 'h', 'a');
  constexpr uint32_t kEncodingExAdobeStandard = ENC_TAG('A', 'D', 'O', 'B');
  constexpr uint32_t kEncodingExAdobeExpert = ENC_TAG('A', 'D', 'B', 'E');
  constexpr uint32_t kEncodingExAdobeCustom = ENC_TAG('A', 'D', 'B', 'C');
  constexpr uint32_t kEncodingExLatin1 = ENC_TAG('l', 'a', 't', '1');
  constexpr uint32_t kEncodingExOldLatin2 = ENC_TAG('l', 'a', 't', '2');
  constexpr uint32_t kEncodingExAppleRoman = ENC_TAG('a', 'r', 'm', 'n');
  
  constexpr uint32_t kEncodingID[] = {
      kEncodingExSymbol,      kEncodingExUnicode,       kEncodingExSjis,
      kEncodingExGB2312,      kEncodingExBig5,          kEncodingExWansung,
      kEncodingExJohab,       kEncodingExAdobeStandard, kEncodingExAdobeExpert,
      kEncodingExAdobeCustom, kEncodingExLatin1,        kEncodingExOldLatin2,
      kEncodingExAppleRoman,
  };
  
  std::unique_ptr<CFX_UnicodeEncodingEx> FXFM_CreateFontEncoding(
      CFX_Font* pFont,
      uint32_t nEncodingID) {
    if (FXFT_Select_Charmap(pFont->GetFaceRec(), nEncodingID))
      return nullptr;
    return std::make_unique<CFX_UnicodeEncodingEx>(pFont, nEncodingID);
  }
  
  }  // namespace
  
  CFX_UnicodeEncodingEx::CFX_UnicodeEncodingEx(CFX_Font* pFont,
                                               uint32_t EncodingID)
      : CFX_UnicodeEncoding(pFont), m_nEncodingID(EncodingID) {}
  
  CFX_UnicodeEncodingEx::~CFX_UnicodeEncodingEx() = default;
  
  uint32_t CFX_UnicodeEncodingEx::GlyphFromCharCode(uint32_t charcode) {
    FXFT_FaceRec* face = m_pFont->GetFaceRec();
    FT_UInt nIndex = FT_Get_Char_Index(face, charcode);
    if (nIndex > 0)
      return nIndex;
    int nmaps = FXFT_Get_Face_CharmapCount(face);
    int m = 0;
    while (m < nmaps) {
      uint32_t nEncodingID =
          FXFT_Get_Charmap_Encoding(FXFT_Get_Face_Charmaps(face)[m++]);
      if (m_nEncodingID == nEncodingID)
        continue;
      int error = FXFT_Select_Charmap(face, nEncodingID);
      if (error)
        continue;
      nIndex = FT_Get_Char_Index(face, charcode);
      if (nIndex > 0) {
        m_nEncodingID = nEncodingID;
        return nIndex;
      }
    }
    FXFT_Select_Charmap(face, m_nEncodingID);
    return 0;
  }
  
  uint32_t CFX_UnicodeEncodingEx::CharCodeFromUnicode(wchar_t Unicode) const {
    if (m_nEncodingID == kEncodingExUnicode ||
        m_nEncodingID == kEncodingExSymbol) {
      return Unicode;
    }
    FXFT_FaceRec* face = m_pFont->GetFaceRec();
    int nmaps = FXFT_Get_Face_CharmapCount(face);
    for (int i = 0; i < nmaps; i++) {
      int nEncodingID =
          FXFT_Get_Charmap_Encoding(FXFT_Get_Face_Charmaps(face)[i]);
      if (nEncodingID == kEncodingExUnicode || nEncodingID == kEncodingExSymbol) {
        return Unicode;
      }
    }
    return kInvalidCharCode;
  }
  
  std::unique_ptr<CFX_UnicodeEncodingEx> FX_CreateFontEncodingEx(
      CFX_Font* pFont) {
    if (!pFont || !pFont->GetFaceRec())
      return nullptr;
  
    for (uint32_t id : kEncodingID) {
      auto pFontEncoding = FXFM_CreateFontEncoding(pFont, id);
      if (pFontEncoding)
        return pFontEncoding;
    }
    return nullptr;
  }
  