OcStringLib: Add OcAsciiStriStr API

Include/Acidanthera/Library/OcStringLib.h

@@ -234,6 +234,38 @@ OcStrniCmp (
   IN UINTN         Length
   );
 
+/**
+  Returns the first occurrence of a Null-terminated ASCII sub-string
+  in a Null-terminated ASCII string through a case insensitive comparison.
+
+  This function scans the contents of the Null-terminated ASCII string
+  specified by String and returns the first occurrence of SearchString.
+  If SearchString is not found in String, then NULL is returned.  If
+  the length of SearchString is zero, then String is returned.
+
+  If String is NULL, then ASSERT().
+  If String is not aligned on a 8-bit boundary, then ASSERT().
+  If SearchString is NULL, then ASSERT().
+  If SearchString is not aligned on a 8-bit boundary, then ASSERT().
+
+  If PcdMaximumAsciiStringLength is not zero, and SearchString
+  or String contains more than PcdMaximumAsciiStringLength ASCII
+  characters, not including the Null-terminator, then ASSERT().
+
+  @param  String          The pointer to a Null-terminated ASCII string.
+  @param  SearchString    The pointer to a Null-terminated ASCII string to search for.
+
+  @retval NULL            If the SearchString does not appear in String.
+  @return others          If there is a match.
+
+**/
+CHAR8 *
+EFIAPI
+OcAsciiStriStr (
+  IN      CONST CHAR8              *String,
+  IN      CONST CHAR8              *SearchString
+  );
+
 /**
   Returns the first occurrence of a Null-terminated Unicode sub-string
   in a Null-terminated Unicode string through a case insensitive comparison.

Library/OcStringLib/OcAsciiLib.c

@@ -206,3 +206,44 @@ OcAsciiEndsWith (
   return StringLength >= SearchStringLength
     && AsciiStrnCmp (&String[StringLength - SearchStringLength], SearchString, SearchStringLength) == 0;
 }
+
+CHAR8 *
+EFIAPI
+OcAsciiStriStr (
+  IN      CONST CHAR8              *String,
+  IN      CONST CHAR8              *SearchString
+  )
+{
+  CONST CHAR8 *FirstMatch;
+  CONST CHAR8 *SearchStringTmp;
+
+  ASSERT (AsciiStrSize (String) != 0);
+  ASSERT (AsciiStrSize (SearchString) != 0);
+
+  if (*SearchString == '\0') {
+    return (CHAR8 *) String;
+  }
+
+  while (*String != '\0') {
+    SearchStringTmp = SearchString;
+    FirstMatch = String;
+
+    while ((AsciiCharToUpper (*String) == AsciiCharToUpper (*SearchStringTmp))
+            && (*String != '\0')) {
+      String++;
+      SearchStringTmp++;
+    }
+
+    if (*SearchStringTmp == '\0') {
+      return (CHAR8 *) FirstMatch;
+    }
+
+    if (*String == '\0') {
+      return NULL;
+    }
+
+    String = FirstMatch + 1;
+  }
+
+  return NULL;
+}