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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package openpgp
import (
"hash"
"io"
)
// NewCanonicalTextHash reformats text written to it into the canonical
// form and then applies the hash h. See RFC 4880, section 5.2.1.
func NewCanonicalTextHash(h hash.Hash) hash.Hash {
return &canonicalTextHash{h, 0}
}
type canonicalTextHash struct {
h hash.Hash
s int
}
var newline = []byte{'\r', '\n'}
func writeCanonical(cw io.Writer, buf []byte, s *int) (int, error) {
start := 0
for i, c := range buf {
switch *s {
case 0:
if c == '\r' {
*s = 1
} else if c == '\n' {
if _, err := cw.Write(buf[start:i]); err != nil {
return 0, err
}
if _, err := cw.Write(newline); err != nil {
return 0, err
}
start = i + 1
}
case 1:
*s = 0
}
}
if _, err := cw.Write(buf[start:]); err != nil {
return 0, err
}
return len(buf), nil
}
func (cth *canonicalTextHash) Write(buf []byte) (int, error) {
return writeCanonical(cth.h, buf, &cth.s)
}
func (cth *canonicalTextHash) Sum(in []byte) []byte {
return cth.h.Sum(in)
}
func (cth *canonicalTextHash) Reset() {
cth.h.Reset()
cth.s = 0
}
func (cth *canonicalTextHash) Size() int {
return cth.h.Size()
}
func (cth *canonicalTextHash) BlockSize() int {
return cth.h.BlockSize()
}
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