+/**\r
+ Check whether the string between a pair of % is a valid envifronment variable name.\r
+\r
+ @param[in] BeginPercent pointer to the first percent.\r
+ @param[in] EndPercent pointer to the last percent.\r
+\r
+ @retval TRUE is a valid environment variable name.\r
+ @retval FALSE is NOT a valid environment variable name.\r
+**/\r
+BOOLEAN\r
+IsValidEnvironmentVariableName(\r
+ IN CONST CHAR16 *BeginPercent,\r
+ IN CONST CHAR16 *EndPercent\r
+ )\r
+{\r
+ CONST CHAR16 *Walker;\r
+ \r
+ Walker = NULL;\r
+\r
+ ASSERT (BeginPercent != NULL);\r
+ ASSERT (EndPercent != NULL);\r
+ ASSERT (BeginPercent < EndPercent);\r
+ \r
+ if ((BeginPercent + 1) == EndPercent) {\r
+ return FALSE;\r
+ }\r
+\r
+ for (Walker = BeginPercent + 1; Walker < EndPercent; Walker++) {\r
+ if (\r
+ (*Walker >= L'0' && *Walker <= L'9') ||\r
+ (*Walker >= L'A' && *Walker <= L'Z') ||\r
+ (*Walker >= L'a' && *Walker <= L'z') ||\r
+ (*Walker == L'_')\r
+ ) {\r
+ if (Walker == BeginPercent + 1 && (*Walker >= L'0' && *Walker <= L'9')) {\r
+ return FALSE;\r
+ } else {\r
+ continue;\r
+ }\r
+ } else {\r
+ return FALSE;\r
+ }\r
+ }\r
+\r
+ return TRUE;\r
+}\r
+\r