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

core/src/fpdftext/fpdf_text_int.cpp

Index: core/src/fpdftext/fpdf_text_int.cpp
diff --git a/core/src/fpdftext/fpdf_text_int.cpp b/core/src/fpdftext/fpdf_text_int.cpp
index 4459552c84f2a73c16420b936a2622b541598c6b..9ab09e19e44dab52fd3a2779ed6d525d95cfa4ae 100644
--- a/core/src/fpdftext/fpdf_text_int.cpp
+++ b/core/src/fpdftext/fpdf_text_int.cpp
@@ -2433,11 +2433,12 @@ FX_BOOL CPDF_TextPageFind::IsMatchWholeWord(const CFX_WideString& csPageText,
   }
   if ((char_left > 'A' && char_left < 'a') ||
       (char_left > 'a' && char_left < 'z') ||
-      (char_left > 0xfb00 && char_left < 0xfb06) || std::isdigit(char_left) ||
+      (char_left > 0xfb00 && char_left < 0xfb06) ||
+      (char_left >= '0' && char_left <= '9') ||
       (char_right > 'A' && char_right < 'a') ||
       (char_right > 'a' && char_right < 'z') ||
       (char_right > 0xfb00 && char_right < 0xfb06) ||
-      std::isdigit(char_right)) {
+      (char_right >= '0' && char_right <= '9')) {
     return FALSE;
   }
   if (!(('A' > char_left || char_left > 'Z') &&