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path: root/vendor/golang.org/x/crypto/openpgp/canonical_text.go
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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"

// 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 (cth *canonicalTextHash) Write(buf []byte) (int, error) {
    start := 0

    for i, c := range buf {
        switch cth.s {
        case 0:
            if c == '\r' {
                cth.s = 1
            } else if c == '\n' {
                cth.h.Write(buf[start:i])
                cth.h.Write(newline)
                start = i + 1
            }
        case 1:
            cth.s = 0
        }
    }

    cth.h.Write(buf[start:])
    return len(buf), nil
}

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()
}