Revert "Revert "Cleanup some numeric code.""

core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp

Index: core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
diff --git a/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp b/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
index 02f0933f360089f2677ae74ed1e2664466a0b51a..b136cfe3619af02b6f8749500b40c5d3280daddf 100644
--- a/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
+++ b/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
@@ -7,6 +7,7 @@
 #include "../../../include/fpdfapi/fpdf_module.h"
 #include "../../../include/fpdfapi/fpdf_page.h"
 #include "../../../include/fpdfapi/fpdf_resource.h"
+#include "../../../include/fxcrt/fx_ext.h"
 #include "../../../include/fxge/fx_freetype.h"
 #include "../../../include/fxge/fx_ge.h"
 #include "../fpdf_cmaps/cmap_int.h"
@@ -190,24 +191,17 @@ FX_DWORD CMap_GetCode(const CFX_ByteStringC& word) {
   if (word.GetAt(0) == '<') {
     for (int i = 1; i < word.GetLength(); i++) {
       uint8_t digit = word.GetAt(i);
-      if (digit >= '0' && digit <= '9') {
-        digit = digit - '0';
-      } else if (digit >= 'a' && digit <= 'f') {
-        digit = digit - 'a' + 10;
-      } else if (digit >= 'A' && digit <= 'F') {
-        digit = digit - 'A' + 10;
-      } else {
-        return num;
-      }
-      num = num * 16 + digit;
-    }
-  } else {
-    for (int i = 0; i < word.GetLength(); i++) {
-      if (word.GetAt(i) < '0' || word.GetAt(i) > '9') {
-        return num;
-      }
-      num = num * 10 + word.GetAt(i) - '0';
+      if (!std::isxdigit(digit))
+        break;
+      num = num * 16 + FXSYS_toHexDigit(digit);
     }
+    return num;
+  }
+
+  for (int i = 0; i < word.GetLength(); i++) {
+    if (!std::isdigit(word.GetAt(i)))
+      break;
+    num = num * 10 + FXSYS_toDecimalDigit(word.GetAt(i));
   }
   return num;
 }
@@ -231,28 +225,18 @@ bool CMap_GetCodeRange(CMap_CodeRange& range,
   for (i = 0; i < range.m_CharSize; ++i) {
     uint8_t digit1 = first.GetAt(i * 2 + 1);
     uint8_t digit2 = first.GetAt(i * 2 + 2);
-    uint8_t byte = (digit1 >= '0' && digit1 <= '9')
-                       ? (digit1 - '0')
-                       : ((digit1 & 0xdf) - 'A' + 10);
-    byte = byte * 16 + ((digit2 >= '0' && digit2 <= '9')
-                            ? (digit2 - '0')
-                            : ((digit2 & 0xdf) - 'A' + 10));
-    range.m_Lower[i] = byte;
+    range.m_Lower[i] = FXSYS_toHexDigit(digit1) * 16 + FXSYS_toHexDigit(digit2);
   }
 
   FX_DWORD size = second.GetLength();
   for (i = 0; i < range.m_CharSize; ++i) {
-    uint8_t digit1 =
-        ((FX_DWORD)i * 2 + 1 < size) ? second.GetAt((FX_STRSIZE)i * 2 + 1) : 0;
-    uint8_t digit2 =
-        ((FX_DWORD)i * 2 + 2 < size) ? second.GetAt((FX_STRSIZE)i * 2 + 2) : 0;
-    uint8_t byte = (digit1 >= '0' && digit1 <= '9')
-                       ? (digit1 - '0')
-                       : ((digit1 & 0xdf) - 'A' + 10);
-    byte = byte * 16 + ((digit2 >= '0' && digit2 <= '9')
-                            ? (digit2 - '0')
-                            : ((digit2 & 0xdf) - 'A' + 10));
-    range.m_Upper[i] = byte;
+    uint8_t digit1 = ((FX_DWORD)i * 2 + 1 < size)
+                         ? second.GetAt((FX_STRSIZE)i * 2 + 1)
+                         : '0';
+    uint8_t digit2 = ((FX_DWORD)i * 2 + 2 < size)
+                         ? second.GetAt((FX_STRSIZE)i * 2 + 2)
+                         : '0';
+    range.m_Upper[i] = FXSYS_toHexDigit(digit1) * 16 + FXSYS_toHexDigit(digit2);
   }
   return true;
 }