Add fallback fonts in pdfium

core/fpdfapi/fpdf_font/cpdf_font.cpp

 // 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/fpdfapi/fpdf_font/include/cpdf_font.h"
 
 #include <memory>
 #include <vector>
 
 #include "core/fpdfapi/fpdf_font/cpdf_truetypefont.h"
 #include "core/fpdfapi/fpdf_font/cpdf_type1font.h"
 #include "core/fpdfapi/fpdf_font/cpdf_type3font.h"
 #include "core/fpdfapi/fpdf_font/font_int.h"
 #include "core/fpdfapi/fpdf_font/include/cpdf_fontencoding.h"
 #include "core/fpdfapi/fpdf_page/cpdf_pagemodule.h"
 #include "core/fpdfapi/fpdf_page/pageint.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_array.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_dictionary.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_document.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_name.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_stream_acc.h"
 #include "core/fpdfapi/include/cpdf_modulemgr.h"
+#include "core/fxcrt/include/fx_memory.h"
 #include "core/fxge/include/fx_freetype.h"
+#include "third_party/base/stl_util.h"
 
 namespace {
 
 const uint8_t kChineseFontNames[][5] = {{0xCB, 0xCE, 0xCC, 0xE5, 0x00},
                                         {0xBF, 0xAC, 0xCC, 0xE5, 0x00},
                                         {0xBA, 0xDA, 0xCC, 0xE5, 0x00},
                                         {0xB7, 0xC2, 0xCB, 0xCE, 0x00},
                                         {0xD0, 0xC2, 0xCB, 0xCE, 0x00}};
 
 void GetPredefinedEncoding(const CFX_ByteString& value, int* basemap) {
@@ skipping 408 matching lines @@
   }
 
   if (!charnames.empty() && !charnames[charcode].IsEmpty())
     return charnames[charcode].c_str();
 
   const FX_CHAR* name = nullptr;
   if (iBaseEncoding)
     name = PDF_CharNameFromPredefinedCharSet(iBaseEncoding, charcode);
   return name && name[0] ? name : nullptr;
 }
+
+uint32_t CPDF_Font::FallbackFontFromCharcode(uint32_t charcode) {
+  if (m_FontFallbacks.empty()) {
+    m_FontFallbacks.push_back(WrapUnique(new CFX_Font()));
+    m_FontFallbacks[0]->LoadSubst("Arial", IsTrueTypeFont(), m_Flags,
+                                  m_StemV * 5, m_ItalicAngle, 0,
+                                  IsVertWriting());
+  }
+  return 0;
+}
+
+int CPDF_Font::FallbackGlyphFromCharcode(int fallbackFont, uint32_t charcode) {
+  if (fallbackFont < 0 ||
+      fallbackFont >= pdfium::CollectionSize<int>(m_FontFallbacks)) {
+    return -1;
+  }
+  int glyph =
+      FXFT_Get_Char_Index(m_FontFallbacks[fallbackFont]->GetFace(), charcode);
+  if (glyph == 0 || glyph == 0xffff)
+    return -1;
+  return glyph;
+}