initial commits

readeol.go

@@ -0,0 +1,83 @@
+package eol
+
+import (
+	"io"
+)
+
+// ReadEOL tries to read and end-of-line character.
+//
+// The end-of-line sequences it supports are:
+//
+//	line-feed       (LF) (U+000A) ('\n')
+//	carriage-return (CR) (U+000D) ('\r')
+//	carriage-return, line-feed    ("\r\n")
+//	new-line        (NL) (U+0085)
+//	line-separator  (LS) (U+2028)
+//
+// If successful, ReadEOL return the end-of-line sequence and the number-of-bytes read.
+func ReadEOL(runescanner io.RuneScanner) (endofline string, size int, err error) {
+	if nil == runescanner {
+		return "", 0, errNilRuneScanner
+	}
+
+	var r0 rune
+	var size0 int
+	{
+		var err error
+
+		r0, size0, err = runescanner.ReadRune()
+		if nil != err {
+			const runeNumber = 1
+			return "", size0, errProblemReadingRune(err, runeNumber)
+		}
+	}
+
+	switch r0 {
+	case lf:
+		return LF, size0, nil
+	case cr:
+		// Nothing here.
+	case nl:
+		return NL, size0, nil
+	case ls:
+		return LS, size0, nil
+	default:
+		err := runescanner.UnreadRune()
+		if nil != err {
+			const runeNumber = 1
+			return "", size0, errProblemUnreadingRune(err, runeNumber, r0)
+		}
+
+		return "", 0, errNotEOL(r0)
+	}
+
+	// if we got here, then we had a CR
+
+	var r1 rune
+	var size1 int
+	{
+		var err error
+
+		r1, size1, err = runescanner.ReadRune()
+		if io.EOF == err {
+			return CR, size0, nil
+		}
+		if nil != err {
+			const runeNumber = 2
+			return "", size1+size0, errProblemReadingRune(err, runeNumber)
+		}
+	}
+
+	switch r1 {
+	case lf:
+		return CRLF, size1+size0, nil
+	default:
+		err := runescanner.UnreadRune()
+		if nil != err {
+			const runeNumber = 2
+			return "", size1+size0, errProblemUnreadingRune(err, runeNumber, r1)
+		}
+
+		return CR, size0, nil
+	}
+}

readeol_test.go

@@ -0,0 +1,203 @@
+package eol_test
+
+import (
+	"testing"
+
+	"io"
+	"strings"
+
+	"sourcecode.social/reiver/go-utf8"
+
+	"sourcecode.social/reiver/go-eol"
+)
+
+func TestReadEOL(t *testing.T) {
+
+	tests := []struct{
+		Value    string
+		ExpectedEOL string
+		ExpectedSize int
+	}{
+		{
+			Value: "\n",
+			ExpectedEOL: eol.LF,
+			ExpectedSize: 1,
+		},
+		{
+			Value: "\r",
+			ExpectedEOL: eol.CR,
+			ExpectedSize: 1,
+		},
+		{
+			Value: "\r\n",
+			ExpectedEOL: eol.CRLF,
+			ExpectedSize: 2,
+		},
+		{
+			Value: "\u0085",
+			ExpectedEOL: eol.NL,
+			ExpectedSize: 2,
+		},
+		{
+			Value: "\u2028",
+			ExpectedEOL: eol.LS,
+			ExpectedSize: 3,
+		},
+
+
+
+		{
+			Value: "\napple banana cherry",
+			ExpectedEOL: eol.LF,
+			ExpectedSize: 1,
+		},
+		{
+			Value: "\rapple banana cherr",
+			ExpectedEOL: eol.CR,
+			ExpectedSize: 1,
+		},
+		{
+			Value: "\r\napple banana cherr",
+			ExpectedEOL: eol.CRLF,
+			ExpectedSize: 2,
+		},
+		{
+			Value: "\u0085apple banana cherr",
+			ExpectedEOL: eol.NL,
+			ExpectedSize: 2,
+		},
+		{
+			Value: "\u2028apple banana cherr",
+			ExpectedEOL: eol.LS,
+			ExpectedSize: 3,
+		},
+	}
+
+	for testNumber, test := range tests {
+
+		var reader io.Reader = strings.NewReader(test.Value)
+		var runescanner io.RuneScanner = utf8.NewRuneScanner(reader)
+
+		actualEOL, actualSize, err := eol.ReadEOL(runescanner)
+		if nil != err {
+			t.Errorf("For test #%d, did not expect an error but actually got one." , testNumber)
+			t.Logf("ERROR: (%T) %s", err, err)
+			t.Logf("VALUE:        %q", test.Value)
+			t.Logf("EXPECTED-EOL: %q", test.ExpectedEOL)
+			t.Logf("EXPECTED-SIZE: %d", test.ExpectedSize)
+			continue
+		}
+
+		{
+			expected := test.ExpectedEOL
+			actual   := actualEOL
+
+			if expected != actual {
+				t.Errorf("For test #%d, the actual end-of-line sequence is not what was expected.", testNumber)
+				t.Logf("EXPECTED: %q", expected)
+				t.Logf("ACTUAL:   %q", actual)
+				t.Logf("VALUE:    %q", test.Value)
+				t.Logf("EXPECTED-SIZE: %d", test.ExpectedSize)
+				continue
+			}
+		}
+
+		{
+			expected := test.ExpectedSize
+			actual   := actualSize
+
+			if expected != actual {
+				t.Errorf("For test #%d, the actual size is not what was expected.", testNumber)
+				t.Logf("EXPECTED: %d", expected)
+				t.Logf("ACTUAL:   %d", actual)
+				t.Logf("VALUE:        %q", test.Value)
+				t.Logf("EXPECTED-EOL: %q", test.ExpectedEOL)
+				continue
+			}
+		}
+	}
+}
+
+func TestReadEOL_fail(t *testing.T) {
+
+	tests := []struct{
+		Value    string
+		ExpectedEOL string
+		ExpectedSize int
+		ExpectedError string
+	}{
+		{
+			Value:               "apple",
+			ExpectedError: "eol: 'a' (U+0061) is not an end-of-line character",
+		},
+		{
+			Value:               "banana",
+			ExpectedError: "eol: 'b' (U+0062) is not an end-of-line character",
+		},
+		{
+			Value:               "cherry",
+			ExpectedError: "eol: 'c' (U+0063) is not an end-of-line character",
+		},
+	}
+
+	for testNumber, test := range tests {
+
+		var reader io.Reader = strings.NewReader(test.Value)
+		var runescanner io.RuneScanner = utf8.NewRuneScanner(reader)
+
+		actualEOL, actualSize, err := eol.ReadEOL(runescanner)
+		if nil == err {
+			t.Errorf("For test #%d, expected an error but did not actually get one." , testNumber)
+			t.Logf("EXPECTED-ERROR: %q", test.ExpectedError)
+			t.Logf("VALUE:        %q", test.Value)
+			t.Logf("EXPECTED-EOL: %q", test.ExpectedEOL)
+			t.Logf("EXPECTED-SIZE: %d", test.ExpectedSize)
+			continue
+		}
+
+		{
+			expected := test.ExpectedError
+			actual   := err.Error()
+
+			if expected != actual {
+				t.Errorf("For test %d, the actual error is not what was expected.", testNumber)
+				t.Logf("EXPECTED: %q", expected)
+				t.Logf("ACTUAL:   %q", actual)
+				t.Logf("VALUE:        %q", test.Value)
+				t.Logf("EXPECTED-EOL: %q", test.ExpectedEOL)
+				t.Logf("EXPECTED-SIZE: %d", test.ExpectedSize)
+				continue
+			}
+		}
+
+		{
+			expected := test.ExpectedEOL
+			actual   := actualEOL
+
+			if expected != actual {
+				t.Errorf("For test %d, the actual end-of-line sequence is not what was expected.", testNumber)
+				t.Logf("EXPECTED: %q", expected)
+				t.Logf("ACTUAL:   %q", actual)
+				t.Logf("VALUE:    %q", test.Value)
+				t.Logf("EXPECTED-SIZE: %d", test.ExpectedSize)
+				t.Logf("EXPECTED-ERROR: %q", test.ExpectedError)
+				continue
+			}
+		}
+
+		{
+			expected := test.ExpectedSize
+			actual   := actualSize
+
+			if expected != actual {
+				t.Errorf("For test %d, the actual size is not what was expected.", testNumber)
+				t.Logf("EXPECTED: %d", expected)
+				t.Logf("ACTUAL:   %d", actual)
+				t.Logf("VALUE:        %q", test.Value)
+				t.Logf("EXPECTED-EOL: %q", test.ExpectedEOL)
+				t.Logf("EXPECTED-ERROR: %q", test.ExpectedError)
+				continue
+			}
+		}
+	}
+}