stdlib: Add StringBuilder.reverse method

2017-04-19 11:43:03 +07:00
parent 5517ed7296
commit f9c6b6e6e4
3 changed files with 130 additions and 0 deletions
@@ -0,0 +1,90 @@
+fun assertEquals(builder: StringBuilder, content: String) {
+    if (builder.toString() != content) throw AssertionError("Test failed: $builder != $content")
+}
+
+fun assertTrue(condition: Boolean) {
+    if (!condition) throw AssertionError("The condition is false")
+}
+
+fun reverseTest(original: String, reversed: String, reversedBack: String) {
+    assertEquals(StringBuilder(original).reverse(), reversed)
+    assertEquals(StringBuilder(reversed).reverse(), reversedBack)
+}
+
+
+fun main(args: Array<String>) {
+    var builder = StringBuilder("123456")
+    assertTrue(builder === builder.reverse())
+    assertEquals(builder, "654321")
+
+    builder.length = 1
+    assertEquals(builder, "6")
+
+    builder.length = 0
+    assertEquals(builder, "")
+
+    var str: String = "a"
+    reverseTest(str, str, str)
+
+    str = "ab"
+    reverseTest(str, "ba", str)
+
+    str = "abcdef"
+    reverseTest(str, "fedcba", str)
+
+    str = "abcdefg"
+    reverseTest(str, "gfedcba", str)
+
+    str = "\ud800\udc00"
+    reverseTest(str, str, str)
+
+    str = "\udc00\ud800"
+    reverseTest(str, "\ud800\udc00", "\ud800\udc00")
+
+    str = "a\ud800\udc00"
+    reverseTest(str, "\ud800\udc00a", str)
+
+    str = "ab\ud800\udc00"
+    reverseTest(str, "\ud800\udc00ba", str)
+
+    str = "abc\ud800\udc00"
+    reverseTest(str, "\ud800\udc00cba", str)
+
+    str = "\ud800\udc00\udc01\ud801\ud802\udc02"
+    reverseTest(str, "\ud802\udc02\ud801\udc01\ud800\udc00",
+            "\ud800\udc00\ud801\udc01\ud802\udc02")
+
+    str = "\ud800\udc00\ud801\udc01\ud802\udc02"
+    reverseTest(str, "\ud802\udc02\ud801\udc01\ud800\udc00", str)
+
+    str = "\ud800\udc00\udc01\ud801a"
+    reverseTest(str, "a\ud801\udc01\ud800\udc00",
+            "\ud800\udc00\ud801\udc01a")
+
+    str = "a\ud800\udc00\ud801\udc01"
+    reverseTest(str, "\ud801\udc01\ud800\udc00a", str)
+
+    str = "\ud800\udc00\udc01\ud801ab"
+    reverseTest(str, "ba\ud801\udc01\ud800\udc00",
+            "\ud800\udc00\ud801\udc01ab")
+
+    str = "ab\ud800\udc00\ud801\udc01"
+    reverseTest(str, "\ud801\udc01\ud800\udc00ba", str)
+
+    str = "\ud800\udc00\ud801\udc01"
+    reverseTest(str, "\ud801\udc01\ud800\udc00", str)
+
+    str = "a\ud800\udc00z\ud801\udc01"
+    reverseTest(str, "\ud801\udc01z\ud800\udc00a", str)
+
+    str = "a\ud800\udc00bz\ud801\udc01"
+    reverseTest(str, "\ud801\udc01zb\ud800\udc00a", str)
+
+    str = "abc\ud802\udc02\ud801\udc01\ud800\udc00"
+    reverseTest(str, "\ud800\udc00\ud801\udc01\ud802\udc02cba", str)
+
+    str = "abcd\ud802\udc02\ud801\udc01\ud800\udc00"
+    reverseTest(str, "\ud800\udc00\ud801\udc01\ud802\udc02dcba", str)
+
+    println("OK")
+}