ShellPkg: Add ShellHexStrToUintn to allow for simple conversion of hex numbers.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jaben Carsey <jaben.carsey@intel.com>
Reviewed-by: Erik Bjorge <erik.c.bjorge@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14893 6f19259b-4bc3-4df7-8a09-765794883524

ShellPkg/Include/Library/ShellLib.h

@@ -1007,6 +1007,23 @@ ShellStrToUintn(
   IN CONST CHAR16 *String
   );
 
+/**
+  Function return the number converted from a hex representation of a number.
+
+  Note: this function cannot be used when (UINTN)(-1), (0xFFFFFFFF) may be a valid
+  result.  Use ShellConvertStringToUint64 instead.
+
+  @param[in] String   String representation of a number.
+
+  @return             The unsigned integer result of the conversion.
+  @retval (UINTN)(-1) An error occured.
+**/
+UINTN
+EFIAPI
+ShellHexStrToUintn(
+  IN CONST CHAR16 *String
+  );
+
 /**
   Safely append with automatic string resizing given length of Destination and
   desired length of copy from Source.

ShellPkg/Library/UefiShellLib/UefiShellLib.c

@@ -3056,6 +3056,32 @@ ShellIsFileInPath(
   return (Status);
 }
 
+/**
+  Function return the number converted from a hex representation of a number.
+
+  Note: this function cannot be used when (UINTN)(-1), (0xFFFFFFFF) may be a valid
+  result.  Use ShellConvertStringToUint64 instead.
+
+  @param[in] String   String representation of a number.
+
+  @return             The unsigned integer result of the conversion.
+  @retval (UINTN)(-1) An error occured.
+**/
+UINTN
+EFIAPI
+ShellHexStrToUintn(
+  IN CONST CHAR16 *String
+  )
+{
+  UINT64        RetVal;
+
+  if (!EFI_ERROR(ShellConvertStringToUint64(String, &RetVal, TRUE, TRUE))) {
+    return ((UINTN)RetVal);
+  }
+  
+  return ((UINTN)(-1));
+}
+
 /**
   Function to determine whether a string is decimal or hex representation of a number
   and return the number converted from the string.  Spaces are always skipped.