Move escape code parser into wcswidth package

tools/wcswidth/escape-code-parser_test.go

@@ -0,0 +1,54 @@
+package wcswidth
+
+import (
+	"testing"
+)
+
+func TestEscapeCodeParsing(t *testing.T) {
+	type test_parse_collection struct {
+		actual, expected string
+	}
+	var d test_parse_collection
+
+	add := func(prefix string, b []byte) error {
+		d.actual += "\n" + prefix + ": " + string(b)
+		return nil
+	}
+
+	var test_parser = EscapeCodeParser{
+		HandleCSI:  func(b []byte) error { return add("CSI", b) },
+		HandleOSC:  func(b []byte) error { return add("OSC", b) },
+		HandleDCS:  func(b []byte) error { return add("DCS", b) },
+		HandleSOS:  func(b []byte) error { return add("SOS", b) },
+		HandlePM:   func(b []byte) error { return add("PM", b) },
+		HandleAPC:  func(b []byte) error { return add("APC", b) },
+		HandleRune: func(b rune) error { return add("CH", []byte(string(b))) },
+	}
+
+	reset_test_parser := func() {
+		test_parser.Reset()
+		d = test_parse_collection{}
+	}
+
+	check_test_result := func(raw string) {
+		if d.actual != d.expected {
+			t.Fatalf("parsing: %#v actual != expected: %#v != %#v", raw, string(d.actual), string(d.expected))
+		}
+	}
+
+	test := func(raw string, expected string) {
+		reset_test_parser()
+		d.expected = "\n" + expected
+		test_parser.Parse([]byte(raw))
+		check_test_result(raw)
+	}
+
+	test("\x1b[31m\xc2\x9bm", "CSI: 31m\nCSI: m")
+	test("ab\nc", "CH: a\nCH: b\nCH: \n\nCH: c")
+	test("a\x1b[200m\x1b[mb\x1b[5:3;2;4~", "CH: a\nCSI: 200m\nCSI: m\nCH: b\nCSI: 5:3;2;4~")
+	test("\x1b[200~a\x1b[201m\x1b[201~\x1b[x", "CH: a\nCH: \x1b\nCH: [\nCH: 2\nCH: 0\nCH: 1\nCH: m\nCSI: x")
+	test("a\x1bPb\x1b\x1bc\x1b\\d", "CH: a\nDCS: b\x1bc\nCH: d")
+	test("a\x1b_b\x1b\x1b\x1bc\x1b\\d", "CH: a\nAPC: b\x1b\x1bc\nCH: d")
+	test("\x1b]X\x07\x1b]X\x1b\x07\x1b\\", "OSC: X\nOSC: X\x1b\x07")
+
+}