Add ArrayList string splitting API

wurst/util/StringUtils.wurst

@@ -1,6 +1,7 @@
 package StringUtils
 import NoWurst
 import LinkedList
+import ArrayList
 import Texttag
 import Interpolation
 import TypeCasting
@@ -108,6 +109,23 @@ public function string.split(string splitBy) returns LinkedList<string>
 		str = second
 	return list
 
+/** Splits into specialized contiguous storage, preserving empty and trailing fields.
+	An empty delimiter returns the original string as one field. The caller owns the list. */
+public function string.splitToArray(string delimiter) returns ArrayList<string>
+	let result = new ArrayList<string>()
+	let offset = delimiter.length()
+	if this == null or offset == 0
+		result.add(this)
+		return result
+	var start = 0
+	var position = this.indexOf(delimiter, start)
+	while position >= 0
+		result.add(start == position ? "" : this.substring(start, position))
+		start = position + offset
+		position = this.indexOf(delimiter, start)
+	result.add(start == this.length() ? "" : this.substring(start, this.length()))
+	return result
+
 /** Replaces consecutive repeats of the same string with a single instance
 	Turns "strstr" into "str" */
 public function string.reduce(string reduced) returns string

wurst/util/StringUtilsTests.wurst

@@ -23,6 +23,31 @@ import ObjectIds
 	(list.size() == 1).assertTrue()
 	destroy list
 
+@Test function splitToArrayPreservesEmptyFieldsAndMultiCharacterDelimiters()
+	let fields = "::alpha::::beta::".splitToArray("::")
+	fields.size().assertEquals(5)
+	fields.get(0).assertEquals("")
+	fields.get(1).assertEquals("alpha")
+	fields.get(2).assertEquals("")
+	fields.get(3).assertEquals("beta")
+	fields.get(4).assertEquals("")
+	destroy fields
+	let empty = "".splitToArray(",")
+	empty.size().assertEquals(1)
+	empty.get(0).assertEquals("")
+	destroy empty
+	let unchanged = "alpha".splitToArray("")
+	unchanged.size().assertEquals(1)
+	unchanged.get(0).assertEquals("alpha")
+	destroy unchanged
+
+@Test function splitToArrayPreservesNullInput()
+	string input = null
+	let fields = input.splitToArray(",")
+	fields.size().assertEquals(1)
+	(fields.get(0) == null).assertTrue()
+	destroy fields
+
 @Test function testJoin()
 	let list = new LinkedList<string>()
 		..add("this", "is", "a", "string")
@@ -74,4 +99,4 @@ import ObjectIds
 	"1-2".isNumber().assertFalse()
 
 @Test function testReplaceChars()
-	"abca".replaceChars("ca", "d").assertEquals("dbdd")
+	"abca".replaceChars("ca", "d").assertEquals("dbdd")