2009-10-12 11:09:35 -06:00
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package strings
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2010-04-20 23:18:26 -06:00
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import (
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"os"
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"utf8"
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)
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2009-10-12 11:09:35 -06:00
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2010-04-20 23:18:26 -06:00
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// A Reader satisfies calls to Read, ReadByte, and ReadRune by
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2009-10-12 11:09:35 -06:00
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// reading from a string.
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type Reader string
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func (r *Reader) Read(b []byte) (n int, err os.Error) {
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2009-12-15 16:40:16 -07:00
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s := *r
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2009-10-12 11:09:35 -06:00
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if len(s) == 0 {
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2009-11-09 13:07:39 -07:00
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return 0, os.EOF
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2009-10-12 11:09:35 -06:00
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}
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for n < len(s) && n < len(b) {
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b[n] = s[n]
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n++
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}
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2009-12-15 16:40:16 -07:00
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*r = s[n:]
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return
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2009-10-12 11:09:35 -06:00
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}
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func (r *Reader) ReadByte() (b byte, err os.Error) {
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2009-12-15 16:40:16 -07:00
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s := *r
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2009-10-12 11:09:35 -06:00
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if len(s) == 0 {
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2009-11-09 13:07:39 -07:00
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return 0, os.EOF
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2009-10-12 11:09:35 -06:00
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}
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2009-12-15 16:40:16 -07:00
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b = s[0]
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*r = s[1:]
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return
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2009-10-12 11:09:35 -06:00
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}
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2010-04-20 23:18:26 -06:00
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// ReadRune reads and returns the next UTF-8-encoded
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// Unicode code point from the buffer.
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// If no bytes are available, the error returned is os.EOF.
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// If the bytes are an erroneous UTF-8 encoding, it
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// consumes one byte and returns U+FFFD, 1.
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func (r *Reader) ReadRune() (rune int, size int, err os.Error) {
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s := *r
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if len(s) == 0 {
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return 0, 0, os.EOF
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}
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c := s[0]
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if c < utf8.RuneSelf {
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*r = s[1:]
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return int(c), 1, nil
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}
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rune, size = utf8.DecodeRuneInString(string(s))
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*r = s[size:]
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return
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}
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2009-10-12 11:09:35 -06:00
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// NewReader returns a new Reader reading from s.
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// It is similar to bytes.NewBufferString but more efficient and read-only.
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func NewReader(s string) *Reader { return (*Reader)(&s) }
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