util/StringUtil: move code to StripRight()

src/util/StringUtil.cxx

@@ -35,17 +35,28 @@ StripLeft(const char *p)
 	return p;
 }
 
-char *
-Strip(char *p)
+size_t
+StripRight(const char *p, size_t length)
 {
-	p = StripLeft(p);
-
-	size_t length = strlen(p);
 	while (length > 0 && IsWhitespaceNotNull(p[length - 1]))
 		--length;
 
-	p[length] = 0;
+	return length;
+}
+
+void
+StripRight(char *p)
+{
+	size_t old_length = strlen(p);
+	size_t new_length = StripRight(p, old_length);
+	p[new_length] = 0;
+}
 
+char *
+Strip(char *p)
+{
+	p = StripLeft(p);
+	StripRight(p);
 	return p;
 }
 

src/util/StringUtil.hxx

@@ -40,6 +40,20 @@ StripLeft(char *p)
 }
 
 /**
+ * Determine the string's length as if it was stripped on the right
+ * side.
+ */
+gcc_pure
+size_t
+StripRight(const char *p, size_t length);
+
+/**
+ * Strip trailing whitespace by null-terminating the string.
+ */
+void
+StripRight(char *p);
+
+/**
  * Skip whitespace at the beginning and terminate the string after the
  * last non-whitespace character.
  */