Add CFX_ByteStringC::CharAt() to avoid c_str() and casts

core/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp

 // Copyright 2014 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_parser/fpdf_parser_utility.h"
 
 #include "core/fpdfapi/fpdf_parser/include/cpdf_array.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_dictionary.h"
@@ skipping 69 matching lines @@
   }
   return -1;
 }
 
 int32_t GetDirectInteger(CPDF_Dictionary* pDict, const CFX_ByteStringC& key) {
   CPDF_Number* pObj = ToNumber(pDict->GetObjectBy(key));
   return pObj ? pObj->GetInteger() : 0;
 }
 
 CFX_ByteString PDF_NameDecode(const CFX_ByteStringC& bstr) {
-  int size = bstr.GetLength();
-  const FX_CHAR* pSrc = bstr.c_str();
   if (bstr.Find('#') == -1)
     return bstr;
 
+  int size = bstr.GetLength();
   CFX_ByteString result;
   FX_CHAR* pDestStart = result.GetBuffer(size);
   FX_CHAR* pDest = pDestStart;
   for (int i = 0; i < size; i++) {
-    if (pSrc[i] == '#' && i < size - 2) {
+    if (bstr[i] == '#' && i < size - 2) {
       *pDest++ =
-          FXSYS_toHexDigit(pSrc[i + 1]) * 16 + FXSYS_toHexDigit(pSrc[i + 2]);
+          FXSYS_toHexDigit(bstr[i + 1]) * 16 + FXSYS_toHexDigit(bstr[i + 2]);
       i += 2;
     } else {
-      *pDest++ = pSrc[i];
+      *pDest++ = bstr[i];
     }
   }
   result.ReleaseBuffer((FX_STRSIZE)(pDest - pDestStart));
   return result;
 }
 
 CFX_ByteString PDF_NameDecode(const CFX_ByteString& orig) {
   if (orig.Find('#') == -1)
     return orig;
   return PDF_NameDecode(orig.AsStringC());
@@ skipping 98 matching lines @@
       buf.AppendBlock(acc.GetData(), acc.GetSize());
       buf << "\r\nendstream";
       break;
     }
     default:
       ASSERT(FALSE);
       break;
   }
   return buf;
 }