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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libgo/go/crypto/openpgp/armor/encode.go | |
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Diffstat (limited to 'libgo/go/crypto/openpgp/armor/encode.go')
-rw-r--r-- | libgo/go/crypto/openpgp/armor/encode.go | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/libgo/go/crypto/openpgp/armor/encode.go b/libgo/go/crypto/openpgp/armor/encode.go new file mode 100644 index 000000000..410e73460 --- /dev/null +++ b/libgo/go/crypto/openpgp/armor/encode.go @@ -0,0 +1,162 @@ +// Copyright 2010 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 armor + +import ( + "encoding/base64" + "io" + "os" +) + +var armorHeaderSep = []byte(": ") +var blockEnd = []byte("\n=") +var newline = []byte("\n") +var armorEndOfLineOut = []byte("-----\n") + +// writeSlices writes its arguments to the given Writer. +func writeSlices(out io.Writer, slices ...[]byte) (err os.Error) { + for _, s := range slices { + _, err := out.Write(s) + if err != nil { + return + } + } + return +} + +// lineBreaker breaks data across several lines, all of the same byte length +// (except possibly the last). Lines are broken with a single '\n'. +type lineBreaker struct { + lineLength int + line []byte + used int + out io.Writer + haveWritten bool +} + +func newLineBreaker(out io.Writer, lineLength int) *lineBreaker { + return &lineBreaker{ + lineLength: lineLength, + line: make([]byte, lineLength), + used: 0, + out: out, + } +} + +func (l *lineBreaker) Write(b []byte) (n int, err os.Error) { + n = len(b) + + if n == 0 { + return + } + + if l.used == 0 && l.haveWritten { + _, err = l.out.Write([]byte{'\n'}) + if err != nil { + return + } + } + + if l.used+len(b) < l.lineLength { + l.used += copy(l.line[l.used:], b) + return + } + + l.haveWritten = true + _, err = l.out.Write(l.line[0:l.used]) + if err != nil { + return + } + excess := l.lineLength - l.used + l.used = 0 + + _, err = l.out.Write(b[0:excess]) + if err != nil { + return + } + + _, err = l.Write(b[excess:]) + return +} + +func (l *lineBreaker) Close() (err os.Error) { + if l.used > 0 { + _, err = l.out.Write(l.line[0:l.used]) + if err != nil { + return + } + } + + return +} + +// encoding keeps track of a running CRC24 over the data which has been written +// to it and outputs a OpenPGP checksum when closed, followed by an armor +// trailer. +// +// It's built into a stack of io.Writers: +// encoding -> base64 encoder -> lineBreaker -> out +type encoding struct { + out io.Writer + breaker *lineBreaker + b64 io.WriteCloser + crc uint32 + blockType []byte +} + +func (e *encoding) Write(data []byte) (n int, err os.Error) { + e.crc = crc24(e.crc, data) + return e.b64.Write(data) +} + +func (e *encoding) Close() (err os.Error) { + err = e.b64.Close() + if err != nil { + return + } + + var checksumBytes [3]byte + checksumBytes[0] = byte(e.crc >> 16) + checksumBytes[1] = byte(e.crc >> 8) + checksumBytes[2] = byte(e.crc) + + var b64ChecksumBytes [4]byte + base64.StdEncoding.Encode(b64ChecksumBytes[:], checksumBytes[:]) + + return writeSlices(e.out, blockEnd, b64ChecksumBytes[:], newline, armorEnd, e.blockType, armorEndOfLine) +} + +// Encode returns a WriteCloser which will encode the data written to it in +// OpenPGP armor. +func Encode(out io.Writer, blockType string, headers map[string]string) (w io.WriteCloser, err os.Error) { + bType := []byte(blockType) + err = writeSlices(out, armorStart, bType, armorEndOfLineOut) + if err != nil { + return + } + + for k, v := range headers { + err = writeSlices(out, []byte(k), armorHeaderSep, []byte(v), newline) + if err != nil { + return + } + } + + if len(headers) > 0 { + _, err := out.Write(newline) + if err != nil { + return + } + } + + e := &encoding{ + out: out, + breaker: newLineBreaker(out, 64), + crc: crc24Init, + blockType: bType, + } + e.b64 = base64.NewEncoder(base64.StdEncoding, e.breaker) + return e, nil +} |