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https://github.com/golang/go
synced 2024-11-21 22:04:39 -07:00
bufio: make the minimum read buffer size 16 bytes.
R=gri, rsc CC=golang-dev https://golang.org/cl/5485067
This commit is contained in:
Rob Pike
parent
5fe96c640a
commit
64776da456
@ -52,12 +52,14 @@ type Reader struct {
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lastRuneSize int
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}
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const minReadBufferSize = 16
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// NewReaderSize creates a new Reader whose buffer has the specified size,
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// which must be greater than one. If the argument io.Reader is already a
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// which must be at least 16 bytes. If the argument io.Reader is already a
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// Reader with large enough size, it returns the underlying Reader.
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// It returns the Reader and any error.
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func NewReaderSize(rd io.Reader, size int) (*Reader, error) {
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if size <= 1 {
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if size < minReadBufferSize {
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return nil, BufSizeError(size)
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}
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// Is it already a Reader?
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@ -135,9 +135,10 @@ var bufreaders = []bufReader{
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{"lines", readLines},
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}
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const minReadBufferSize = 16
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var bufsizes = []int{
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2, 3, 4, 5, 6, 7, 8, 9, 10,
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23, 32, 46, 64, 93, 128, 1024, 4096,
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minReadBufferSize, 23, 32, 46, 64, 93, 128, 1024, 4096,
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}
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func TestReader(t *testing.T) {
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@ -514,27 +515,32 @@ func TestWriteString(t *testing.T) {
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}
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func TestBufferFull(t *testing.T) {
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buf, _ := NewReaderSize(strings.NewReader("hello, world"), 5)
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line, err := buf.ReadSlice(',')
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if string(line) != "hello" || err != ErrBufferFull {
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const longString = "And now, hello, world! It is the time for all good men to come to the aid of their party"
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buf, err := NewReaderSize(strings.NewReader(longString), minReadBufferSize)
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if err != nil {
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t.Fatal("NewReaderSize:", err)
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}
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line, err := buf.ReadSlice('!')
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if string(line) != "And now, hello, " || err != ErrBufferFull {
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t.Errorf("first ReadSlice(,) = %q, %v", line, err)
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}
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line, err = buf.ReadSlice(',')
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if string(line) != "," || err != nil {
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line, err = buf.ReadSlice('!')
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if string(line) != "world!" || err != nil {
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t.Errorf("second ReadSlice(,) = %q, %v", line, err)
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}
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}
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func TestPeek(t *testing.T) {
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p := make([]byte, 10)
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buf, _ := NewReaderSize(strings.NewReader("abcdefghij"), 4)
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// string is 16 (minReadBufferSize) long.
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buf, _ := NewReaderSize(strings.NewReader("abcdefghijklmnop"), minReadBufferSize)
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if s, err := buf.Peek(1); string(s) != "a" || err != nil {
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t.Fatalf("want %q got %q, err=%v", "a", string(s), err)
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}
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if s, err := buf.Peek(4); string(s) != "abcd" || err != nil {
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t.Fatalf("want %q got %q, err=%v", "abcd", string(s), err)
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}
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if _, err := buf.Peek(5); err != ErrBufferFull {
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if _, err := buf.Peek(32); err != ErrBufferFull {
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t.Fatalf("want ErrBufFull got %v", err)
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}
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if _, err := buf.Read(p[0:3]); string(p[0:3]) != "abc" || err != nil {
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@ -552,8 +558,8 @@ func TestPeek(t *testing.T) {
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if s, err := buf.Peek(4); string(s) != "ghij" || err != nil {
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t.Fatalf("want %q got %q, err=%v", "ghij", string(s), err)
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}
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if _, err := buf.Read(p[0:4]); string(p[0:4]) != "ghij" || err != nil {
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t.Fatalf("want %q got %q, err=%v", "ghij", string(p[0:3]), err)
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if _, err := buf.Read(p[0:]); string(p[0:]) != "ghijklmnop" || err != nil {
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t.Fatalf("want %q got %q, err=%v", "ghijklmnop", string(p[0:minReadBufferSize]), err)
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}
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if s, err := buf.Peek(0); string(s) != "" || err != nil {
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t.Fatalf("want %q got %q, err=%v", "", string(s), err)
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@ -635,19 +641,25 @@ func TestReadLine(t *testing.T) {
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}
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func TestLineTooLong(t *testing.T) {
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buf := bytes.NewBuffer([]byte("aaabbbcc\n"))
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l, _ := NewReaderSize(buf, 3)
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data := make([]byte, 0)
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for i := 0; i < minReadBufferSize*5/2; i++ {
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data = append(data, '0'+byte(i%10))
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}
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buf := bytes.NewBuffer(data)
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l, _ := NewReaderSize(buf, minReadBufferSize)
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line, isPrefix, err := l.ReadLine()
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if !isPrefix || !bytes.Equal(line, []byte("aaa")) || err != nil {
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t.Errorf("bad result for first line: %x %s", line, err)
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if !isPrefix || !bytes.Equal(line, data[:minReadBufferSize]) || err != nil {
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t.Errorf("bad result for first line: got %q want %q %v", line, data[:minReadBufferSize], err)
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}
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data = data[len(line):]
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line, isPrefix, err = l.ReadLine()
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if !isPrefix || !bytes.Equal(line, []byte("bbb")) || err != nil {
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t.Errorf("bad result for second line: %x", line)
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if !isPrefix || !bytes.Equal(line, data[:minReadBufferSize]) || err != nil {
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t.Errorf("bad result for second line: got %q want %q %v", line, data[:minReadBufferSize], err)
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}
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data = data[len(line):]
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line, isPrefix, err = l.ReadLine()
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if isPrefix || !bytes.Equal(line, []byte("cc")) || err != nil {
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t.Errorf("bad result for third line: %x", line)
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if isPrefix || !bytes.Equal(line, data[:minReadBufferSize/2]) || err != nil {
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t.Errorf("bad result for third line: got %q want %q %v", line, data[:minReadBufferSize/2], err)
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}
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line, isPrefix, err = l.ReadLine()
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if isPrefix || err == nil {
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@ -656,8 +668,8 @@ func TestLineTooLong(t *testing.T) {
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}
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func TestReadAfterLines(t *testing.T) {
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line1 := "line1"
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restData := "line2\nline 3\n"
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line1 := "this is line1"
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restData := "this is line2\nthis is line 3\n"
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inbuf := bytes.NewBuffer([]byte(line1 + "\n" + restData))
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outbuf := new(bytes.Buffer)
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maxLineLength := len(line1) + len(restData)/2
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@ -676,7 +688,7 @@ func TestReadAfterLines(t *testing.T) {
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}
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func TestReadEmptyBuffer(t *testing.T) {
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l, _ := NewReaderSize(bytes.NewBuffer(nil), 10)
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l, _ := NewReaderSize(bytes.NewBuffer(nil), minReadBufferSize)
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line, isPrefix, err := l.ReadLine()
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if err != io.EOF {
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t.Errorf("expected EOF from ReadLine, got '%s' %t %s", line, isPrefix, err)
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@ -684,7 +696,7 @@ func TestReadEmptyBuffer(t *testing.T) {
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}
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func TestLinesAfterRead(t *testing.T) {
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l, _ := NewReaderSize(bytes.NewBuffer([]byte("foo")), 10)
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l, _ := NewReaderSize(bytes.NewBuffer([]byte("foo")), minReadBufferSize)
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_, err := ioutil.ReadAll(l)
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if err != nil {
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t.Error(err)
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@ -715,34 +727,19 @@ type readLineResult struct {
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}
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var readLineNewlinesTests = []struct {
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input string
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bufSize int
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expect []readLineResult
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input string
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expect []readLineResult
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}{
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{"h\r\nb\r\n", 2, []readLineResult{
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{[]byte("h"), true, nil},
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{"012345678901234\r\n012345678901234\r\n", []readLineResult{
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{[]byte("012345678901234"), true, nil},
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{nil, false, nil},
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{[]byte("b"), true, nil},
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{[]byte("012345678901234"), true, nil},
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{nil, false, nil},
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{nil, false, io.EOF},
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}},
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{"hello\r\nworld\r\n", 6, []readLineResult{
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{[]byte("hello"), true, nil},
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{nil, false, nil},
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{[]byte("world"), true, nil},
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{nil, false, nil},
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{nil, false, io.EOF},
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}},
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{"hello\rworld\r", 6, []readLineResult{
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{[]byte("hello"), true, nil},
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{[]byte("\rworld"), true, nil},
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{[]byte("\r"), false, nil},
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{nil, false, io.EOF},
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}},
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{"h\ri\r\n\r", 2, []readLineResult{
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{[]byte("h"), true, nil},
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{[]byte("\ri"), true, nil},
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{nil, false, nil},
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{"0123456789012345\r012345678901234\r", []readLineResult{
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{[]byte("0123456789012345"), true, nil},
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{[]byte("\r012345678901234"), true, nil},
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{[]byte("\r"), false, nil},
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{nil, false, io.EOF},
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}},
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@ -750,12 +747,12 @@ var readLineNewlinesTests = []struct {
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func TestReadLineNewlines(t *testing.T) {
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for _, e := range readLineNewlinesTests {
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testReadLineNewlines(t, e.input, e.bufSize, e.expect)
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testReadLineNewlines(t, e.input, e.expect)
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}
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}
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func testReadLineNewlines(t *testing.T, input string, bufSize int, expect []readLineResult) {
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b, err := NewReaderSize(strings.NewReader(input), bufSize)
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func testReadLineNewlines(t *testing.T, input string, expect []readLineResult) {
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b, err := NewReaderSize(strings.NewReader(input), minReadBufferSize)
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if err != nil {
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t.Fatal(err)
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}
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