Elia Battiston | be9edc1 | 2022-03-09 11:35:58 +0100 | [diff] [blame] | 1 | // Copyright 2011 The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | package norm |
| 6 | |
| 7 | import "io" |
| 8 | |
| 9 | type normWriter struct { |
| 10 | rb reorderBuffer |
| 11 | w io.Writer |
| 12 | buf []byte |
| 13 | } |
| 14 | |
| 15 | // Write implements the standard write interface. If the last characters are |
| 16 | // not at a normalization boundary, the bytes will be buffered for the next |
| 17 | // write. The remaining bytes will be written on close. |
| 18 | func (w *normWriter) Write(data []byte) (n int, err error) { |
| 19 | // Process data in pieces to keep w.buf size bounded. |
| 20 | const chunk = 4000 |
| 21 | |
| 22 | for len(data) > 0 { |
| 23 | // Normalize into w.buf. |
| 24 | m := len(data) |
| 25 | if m > chunk { |
| 26 | m = chunk |
| 27 | } |
| 28 | w.rb.src = inputBytes(data[:m]) |
| 29 | w.rb.nsrc = m |
| 30 | w.buf = doAppend(&w.rb, w.buf, 0) |
| 31 | data = data[m:] |
| 32 | n += m |
| 33 | |
| 34 | // Write out complete prefix, save remainder. |
| 35 | // Note that lastBoundary looks back at most 31 runes. |
| 36 | i := lastBoundary(&w.rb.f, w.buf) |
| 37 | if i == -1 { |
| 38 | i = 0 |
| 39 | } |
| 40 | if i > 0 { |
| 41 | if _, err = w.w.Write(w.buf[:i]); err != nil { |
| 42 | break |
| 43 | } |
| 44 | bn := copy(w.buf, w.buf[i:]) |
| 45 | w.buf = w.buf[:bn] |
| 46 | } |
| 47 | } |
| 48 | return n, err |
| 49 | } |
| 50 | |
| 51 | // Close forces data that remains in the buffer to be written. |
| 52 | func (w *normWriter) Close() error { |
| 53 | if len(w.buf) > 0 { |
| 54 | _, err := w.w.Write(w.buf) |
| 55 | if err != nil { |
| 56 | return err |
| 57 | } |
| 58 | } |
| 59 | return nil |
| 60 | } |
| 61 | |
| 62 | // Writer returns a new writer that implements Write(b) |
| 63 | // by writing f(b) to w. The returned writer may use an |
| 64 | // internal buffer to maintain state across Write calls. |
| 65 | // Calling its Close method writes any buffered data to w. |
| 66 | func (f Form) Writer(w io.Writer) io.WriteCloser { |
| 67 | wr := &normWriter{rb: reorderBuffer{}, w: w} |
| 68 | wr.rb.init(f, nil) |
| 69 | return wr |
| 70 | } |
| 71 | |
| 72 | type normReader struct { |
| 73 | rb reorderBuffer |
| 74 | r io.Reader |
| 75 | inbuf []byte |
| 76 | outbuf []byte |
| 77 | bufStart int |
| 78 | lastBoundary int |
| 79 | err error |
| 80 | } |
| 81 | |
| 82 | // Read implements the standard read interface. |
| 83 | func (r *normReader) Read(p []byte) (int, error) { |
| 84 | for { |
| 85 | if r.lastBoundary-r.bufStart > 0 { |
| 86 | n := copy(p, r.outbuf[r.bufStart:r.lastBoundary]) |
| 87 | r.bufStart += n |
| 88 | if r.lastBoundary-r.bufStart > 0 { |
| 89 | return n, nil |
| 90 | } |
| 91 | return n, r.err |
| 92 | } |
| 93 | if r.err != nil { |
| 94 | return 0, r.err |
| 95 | } |
| 96 | outn := copy(r.outbuf, r.outbuf[r.lastBoundary:]) |
| 97 | r.outbuf = r.outbuf[0:outn] |
| 98 | r.bufStart = 0 |
| 99 | |
| 100 | n, err := r.r.Read(r.inbuf) |
| 101 | r.rb.src = inputBytes(r.inbuf[0:n]) |
| 102 | r.rb.nsrc, r.err = n, err |
| 103 | if n > 0 { |
| 104 | r.outbuf = doAppend(&r.rb, r.outbuf, 0) |
| 105 | } |
| 106 | if err == io.EOF { |
| 107 | r.lastBoundary = len(r.outbuf) |
| 108 | } else { |
| 109 | r.lastBoundary = lastBoundary(&r.rb.f, r.outbuf) |
| 110 | if r.lastBoundary == -1 { |
| 111 | r.lastBoundary = 0 |
| 112 | } |
| 113 | } |
| 114 | } |
| 115 | } |
| 116 | |
| 117 | // Reader returns a new reader that implements Read |
| 118 | // by reading data from r and returning f(data). |
| 119 | func (f Form) Reader(r io.Reader) io.Reader { |
| 120 | const chunk = 4000 |
| 121 | buf := make([]byte, chunk) |
| 122 | rr := &normReader{rb: reorderBuffer{}, r: r, inbuf: buf} |
| 123 | rr.rb.init(f, buf) |
| 124 | return rr |
| 125 | } |