bytes: Add Buffer.ReadBytes, Buffer.ReadString

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4000046

diff --git a/src/pkg/bufio/bufio.go b/src/pkg/bufio/bufio.go
index c13456a6326b78ec9c3200d932cba7808d551578..67b7cdb53c358a2d385d4bf7145895137fa94cd8 100644 (file)
--- a/src/pkg/bufio/bufio.go
+++ b/src/pkg/bufio/bufio.go
@@ -286,7 +286,8 @@ func (b *Reader) ReadSlice(delim byte) (line []byte, err os.Error) {
 // returning a slice containing the data up to and including the delimiter.
 // If ReadBytes encounters an error before finding a delimiter,
 // it returns the data read before the error and the error itself (often os.EOF).
-// ReadBytes returns err != nil if and only if line does not end in delim.
+// ReadBytes returns err != nil if and only if the returned data does not end in
+// delim.
 func (b *Reader) ReadBytes(delim byte) (line []byte, err os.Error) {
        // Use ReadSlice to look for array,
        // accumulating full buffers.
@@ -332,7 +333,8 @@ func (b *Reader) ReadBytes(delim byte) (line []byte, err os.Error) {
 // returning a string containing the data up to and including the delimiter.
 // If ReadString encounters an error before finding a delimiter,
 // it returns the data read before the error and the error itself (often os.EOF).
-// ReadString returns err != nil if and only if line does not end in delim.
+// ReadString returns err != nil if and only if the returned data does not end in
+// delim.
 func (b *Reader) ReadString(delim byte) (line string, err os.Error) {
        bytes, e := b.ReadBytes(delim)
        return string(bytes), e

diff --git a/src/pkg/bytes/buffer.go b/src/pkg/bytes/buffer.go
index 62cf82810e79204add4496491615bc28d8c1e898..4aa74371f1211f793336c91f81ecff24b5cc50f4 100644 (file)
--- a/src/pkg/bytes/buffer.go
+++ b/src/pkg/bytes/buffer.go
@@ -301,6 +301,35 @@ func (b *Buffer) UnreadByte() os.Error {
        return nil
 }
 
+// ReadBytes reads until the first occurrence of delim in the input,
+// returning a slice containing the data up to and including the delimiter.
+// If ReadBytes encounters an error before finding a delimiter,
+// it returns the data read before the error and the error itself (often os.EOF).
+// ReadBytes returns err != nil if and only if the returned data does not end in
+// delim.
+func (b *Buffer) ReadBytes(delim byte) (line []byte, err os.Error) {
+       i := IndexByte(b.buf[b.off:], delim)
+       size := i + 1 - b.off
+       if i < 0 {
+               size = len(b.buf) - b.off
+               err = os.EOF
+       }
+       line = make([]byte, size)
+       copy(line, b.buf[b.off:])
+       return
+}
+
+// ReadString reads until the first occurrence of delim in the input,
+// returning a string containing the data up to and including the delimiter.
+// If ReadString encounters an error before finding a delimiter,
+// it returns the data read before the error and the error itself (often os.EOF).
+// ReadString returns err != nil if and only if the returned data does not end
+// in delim.
+func (b *Buffer) ReadString(delim byte) (line string, err os.Error) {
+       bytes, err := b.ReadBytes(delim)
+       return string(bytes), err
+}
+
 // NewBuffer creates and initializes a new Buffer using buf as its initial
 // contents.  It is intended to prepare a Buffer to read existing data.  It
 // can also be used to size the internal buffer for writing.  To do that,

diff --git a/src/pkg/bytes/buffer_test.go b/src/pkg/bytes/buffer_test.go
index 509793d24a8293331ffcc297d6493a42d8c0ca85..2af9ffdefa6e843b1fecaf67dd332f4baabed124 100644 (file)
--- a/src/pkg/bytes/buffer_test.go
+++ b/src/pkg/bytes/buffer_test.go
@@ -6,6 +6,7 @@ package bytes_test
 
 import (
        . "bytes"
+       "os"
        "rand"
        "testing"
        "utf8"
@@ -238,7 +239,7 @@ func TestMixedReadsAndWrites(t *testing.T) {
 func TestNil(t *testing.T) {
        var b *Buffer
        if b.String() != "<nil>" {
-               t.Errorf("expcted <nil>; got %q", b.String())
+               t.Errorf("expected <nil>; got %q", b.String())
        }
 }
 
@@ -347,3 +348,27 @@ func TestNext(t *testing.T) {
                }
        }
 }
+
+var readBytesTests = []struct {
+       buffer   []byte
+       delim    byte
+       expected []byte
+       err      os.Error
+}{
+       {err: os.EOF},
+       {[]byte{}, 0, []byte{}, os.EOF},
+       {[]byte("a\x00"), 0, []byte("a\x00"), nil},
+       {[]byte("hello\x01world"), 1, []byte("hello\x01"), nil},
+       {[]byte("foo\nbar"), 0, []byte("foo\nbar"), os.EOF},
+       {[]byte("alpha beta gamma"), ' ', []byte("alpha "), nil},
+}
+
+func TestReadBytes(t *testing.T) {
+       for _, test := range readBytesTests {
+               buf := NewBuffer(test.buffer)
+               bytes, err := buf.ReadBytes(test.delim)
+               if !Equal(bytes, test.expected) || err != test.err {
+                       t.Errorf("expected %q, %v got %q, %v", test.expected, test.err, bytes, err)
+               }
+       }
+}