github.com/graybobo/golang.org-package-offline-cache@v0.0.0-20200626051047-6608995c132f/x/crypto/openpgp/canonical_text.go (about)

     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 openpgp
     6  
     7  import "hash"
     8  
     9  // NewCanonicalTextHash reformats text written to it into the canonical
    10  // form and then applies the hash h.  See RFC 4880, section 5.2.1.
    11  func NewCanonicalTextHash(h hash.Hash) hash.Hash {
    12  	return &canonicalTextHash{h, 0}
    13  }
    14  
    15  type canonicalTextHash struct {
    16  	h hash.Hash
    17  	s int
    18  }
    19  
    20  var newline = []byte{'\r', '\n'}
    21  
    22  func (cth *canonicalTextHash) Write(buf []byte) (int, error) {
    23  	start := 0
    24  
    25  	for i, c := range buf {
    26  		switch cth.s {
    27  		case 0:
    28  			if c == '\r' {
    29  				cth.s = 1
    30  			} else if c == '\n' {
    31  				cth.h.Write(buf[start:i])
    32  				cth.h.Write(newline)
    33  				start = i + 1
    34  			}
    35  		case 1:
    36  			cth.s = 0
    37  		}
    38  	}
    39  
    40  	cth.h.Write(buf[start:])
    41  	return len(buf), nil
    42  }
    43  
    44  func (cth *canonicalTextHash) Sum(in []byte) []byte {
    45  	return cth.h.Sum(in)
    46  }
    47  
    48  func (cth *canonicalTextHash) Reset() {
    49  	cth.h.Reset()
    50  	cth.s = 0
    51  }
    52  
    53  func (cth *canonicalTextHash) Size() int {
    54  	return cth.h.Size()
    55  }
    56  
    57  func (cth *canonicalTextHash) BlockSize() int {
    58  	return cth.h.BlockSize()
    59  }