Revert "Revert "Revert "Cleanup some numeric code."""

core/src/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 "../../../include/fpdfapi/fpdf_parser.h"
-#include "../../../include/fxcrt/fx_ext.h"
 
 // Indexed by 8-bit character code, contains either:
 //   'W' - for whitespace: NUL, TAB, CR, LF, FF, 0x80, 0xff
 //   'N' - for numeric: 0123456789+-.
 //   'D' - for delimiter: %()/<>[]{}
 //   'R' - otherwise.
 const char PDF_CharType[256] = {
     // NUL  SOH  STX  ETX  EOT  ENQ  ACK  BEL  BS   HT   LF   VT   FF   CR   SO
     // SI
     'W', 'R', 'R', 'R', 'R', 'R', 'R', 'R', 'R', 'W', 'W', 'R', 'W', 'W', 'R',
@@ skipping 254 matching lines @@
       if (buf_count < nParams) {
         continue;
       }
       m_dwCurPos = pBuf[buf_index];
       FX_Free(pBuf);
       return TRUE;
     }
   }
   return FALSE;
 }
-
+static int _hex2dec(char ch) {
+  if (ch >= '0' && ch <= '9') {
+    return ch - '0';
+  }
+  if (ch >= 'a' && ch <= 'f') {
+    return ch - 'a' + 10;
+  }
+  if (ch >= 'A' && ch <= 'F') {
+    return ch - 'A' + 10;
+  }
+  return 0;
+}
 CFX_ByteString PDF_NameDecode(const CFX_ByteStringC& bstr) {
   int size = bstr.GetLength();
   const FX_CHAR* pSrc = bstr.GetCStr();
   if (FXSYS_memchr(pSrc, '#', size) == NULL) {
     return bstr;
   }
   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) {
-      *pDest++ =
-          FXSYS_toHexDigit(pSrc[i + 1]) * 16 + FXSYS_toHexDigit(pSrc[i + 2]);
+      *pDest++ = _hex2dec(pSrc[i + 1]) * 16 + _hex2dec(pSrc[i + 2]);
       i += 2;
     } else {
       *pDest++ = pSrc[i];
     }
   }
   result.ReleaseBuffer((FX_STRSIZE)(pDest - pDestStart));
   return result;
 }
 CFX_ByteString PDF_NameDecode(const CFX_ByteString& orig) {
   if (FXSYS_memchr(orig.c_str(), '#', orig.GetLength()) == NULL) {
@@ skipping 148 matching lines @@
     CPDF_Object* pFound = SearchNumberNode(pKid, num);
     if (pFound) {
       return pFound;
     }
   }
   return NULL;
 }
 CPDF_Object* CPDF_NumberTree::LookupValue(int num) {
   return SearchNumberNode(m_pRoot, num);
 }