Golang bytes.Copy函数代码示例

func (m *clientHelloMsg) marshal() []byte {
	if m.raw != nil {
		return m.raw
	}

	length := 2 + 32 + 1 + len(m.sessionId) + 2 + len(m.cipherSuites)*2 + 1 + len(m.compressionMethods)
	x := make([]byte, 4+length)
	x[0] = typeClientHello
	x[1] = uint8(length >> 16)
	x[2] = uint8(length >> 8)
	x[3] = uint8(length)
	x[4] = m.major
	x[5] = m.minor
	bytes.Copy(x[6:38], m.random)
	x[38] = uint8(len(m.sessionId))
	bytes.Copy(x[39:39+len(m.sessionId)], m.sessionId)
	y := x[39+len(m.sessionId) : len(x)]
	y[0] = uint8(len(m.cipherSuites) >> 7)
	y[1] = uint8(len(m.cipherSuites) << 1)
	for i, suite := range m.cipherSuites {
		y[2+i*2] = uint8(suite >> 8)
		y[3+i*2] = uint8(suite)
	}
	z := y[2+len(m.cipherSuites)*2 : len(y)]
	z[0] = uint8(len(m.compressionMethods))
	bytes.Copy(z[1:len(z)], m.compressionMethods)
	m.raw = x

	return x
}

func main() {
	in = bufio.NewReader(os.Stdin)
	buf := make([]byte, 100*1024)
	top := 0
	for {
		line, err := in.ReadSlice('\n')
		if err != nil {
			break
		}
		if line[0] == '>' {
			if top > 0 {
				output(buf[0:top])
				top = 0
			}
			os.Stdout.Write(line)
			continue
		}
		line = line[0 : len(line)-1] // drop newline
		if top+len(line) > len(buf) {
			nbuf := make([]byte, 2*len(buf)+1024*(100+len(line)))
			bytes.Copy(nbuf, buf[0:top])
			buf = nbuf
		}
		bytes.Copy(buf[top:len(buf)], line)
		top += len(line)
	}
	output(buf[0:top])
}

// EncryptOAEP encrypts the given message with RSA-OAEP.
// The message must be no longer than the length of the public modulus less
// twice the hash length plus 2.
func EncryptOAEP(hash hash.Hash, rand io.Reader, pub *PublicKey, msg []byte, label []byte) (out []byte, err os.Error) {
	hash.Reset()
	k := (pub.N.Len() + 7) / 8
	if len(msg) > k-2*hash.Size()-2 {
		err = MessageTooLongError{}
		return
	}

	hash.Write(label)
	lHash := hash.Sum()
	hash.Reset()

	em := make([]byte, k)
	seed := em[1 : 1+hash.Size()]
	db := em[1+hash.Size() : len(em)]

	bytes.Copy(db[0:hash.Size()], lHash)
	db[len(db)-len(msg)-1] = 1
	bytes.Copy(db[len(db)-len(msg):len(db)], msg)

	_, err = io.ReadFull(rand, seed)
	if err != nil {
		return
	}

	mgf1XOR(db, hash, seed)
	mgf1XOR(seed, hash, db)

	m := new(big.Int)
	m.SetBytes(em)
	c := encrypt(new(big.Int), pub, m)
	out = c.Bytes()
	return
}

// finishedSum calculates the contents of the verify_data member of a Finished
// message given the MD5 and SHA1 hashes of a set of handshake messages.
func finishedSum(md5, sha1, label, masterSecret []byte) []byte {
	seed := make([]byte, len(md5)+len(sha1))
	bytes.Copy(seed, md5)
	bytes.Copy(seed[len(md5):len(seed)], sha1)
	out := make([]byte, finishedVerifyLength)
	pRF11(out, masterSecret, label, seed)
	return out
}

// WriteHeader writes hdr and prepares to accept the file's contents.
// WriteHeader calls Flush if it is not the first header.
func (tw *Writer) WriteHeader(hdr *Header) os.Error {
	if tw.err == nil {
		tw.Flush()
	}
	if tw.err != nil {
		return tw.err
	}

	tw.nb = int64(hdr.Size)
	tw.pad = -tw.nb & (blockSize - 1) // blockSize is a power of two

	header := make([]byte, blockSize)
	s := slicer(header)

	// TODO(dsymonds): handle names longer than 100 chars
	bytes.Copy(s.next(100), strings.Bytes(hdr.Name))

	tw.octal(s.next(8), hdr.Mode)                       // 100:108
	tw.numeric(s.next(8), hdr.Uid)                      // 108:116
	tw.numeric(s.next(8), hdr.Gid)                      // 116:124
	tw.numeric(s.next(12), hdr.Size)                    // 124:136
	tw.numeric(s.next(12), hdr.Mtime)                   // 136:148
	s.next(8)                                           // chksum (148:156)
	s.next(1)[0] = hdr.Typeflag                         // 156:157
	s.next(100)                                         // linkname (157:257)
	bytes.Copy(s.next(8), strings.Bytes("ustar\x0000")) // 257:265
	tw.cString(s.next(32), hdr.Uname)                   // 265:297
	tw.cString(s.next(32), hdr.Gname)                   // 297:329
	tw.numeric(s.next(8), hdr.Devmajor)                 // 329:337
	tw.numeric(s.next(8), hdr.Devminor)                 // 337:345

	// Use the GNU magic instead of POSIX magic if we used any GNU extensions.
	if tw.usedBinary {
		bytes.Copy(header[257:265], strings.Bytes("ustar  \x00"))
	}

	// The chksum field is terminated by a NUL and a space.
	// This is different from the other octal fields.
	chksum, _ := checksum(header)
	tw.octal(header[148:155], chksum)
	header[155] = ' '

	if tw.err != nil {
		// problem with header; probably integer too big for a field.
		return tw.err
	}

	_, tw.err = tw.w.Write(header)

	return tw.err
}

func (p *recordProcessor) processHandshakeRecord(data []byte) {
	if p.handshakeBuf == nil {
		p.handshakeBuf = data
	} else {
		if len(p.handshakeBuf) > maxHandshakeMsg {
			p.error(alertInternalError)
			return
		}
		newBuf := make([]byte, len(p.handshakeBuf)+len(data))
		bytes.Copy(newBuf, p.handshakeBuf)
		bytes.Copy(newBuf[len(p.handshakeBuf):len(newBuf)], data)
		p.handshakeBuf = newBuf
	}

	for len(p.handshakeBuf) >= 4 {
		handshakeLen := int(p.handshakeBuf[1])<<16 |
			int(p.handshakeBuf[2])<<8 |
			int(p.handshakeBuf[3])
		if handshakeLen+4 > len(p.handshakeBuf) {
			break
		}

		bytes := p.handshakeBuf[0 : handshakeLen+4]
		p.handshakeBuf = p.handshakeBuf[handshakeLen+4 : len(p.handshakeBuf)]
		if bytes[0] == typeFinished {
			// Special case because Finished is synchronous: the
			// handshake handler has to tell us if it's ok to start
			// forwarding application data.
			m := new(finishedMsg)
			if !m.unmarshal(bytes) {
				p.error(alertUnexpectedMessage)
			}
			p.handshakeChan <- m
			var ok bool
			p.connState, ok = (<-p.controlChan).(ConnectionState)
			if !ok || p.connState.Error != 0 {
				p.shutdown = true
				return
			}
		} else {
			msg, ok := parseHandshakeMsg(bytes)
			if !ok {
				p.error(alertUnexpectedMessage)
				return
			}
			p.handshakeChan <- msg
		}
	}
}

// RepeatFasta prints the characters of the byte slice s. When it
// reaches the end of the slice, it goes back to the beginning.
// It stops after generating count characters.
// After each WIDTH characters it prints a newline.
// It assumes that WIDTH <= len(s) + 1.
func RepeatFasta(s []byte, count int) {
	pos := 0;
	s2 := make([]byte, len(s) + WIDTH);
	bytes.Copy(s2, s);
	bytes.Copy(s2[len(s):len(s2)], s);
	for count > 0 {
		line := min(WIDTH, count);
		out.Write(s2[pos:pos+line]);
		out.WriteByte('\n');
		pos += line;
		if pos >= len(s) {
			pos -= len(s);
		}
		count -= line;
	}
}

func (tls *Conn) Read(p []byte) (int, os.Error) {
	if len(tls.readBuf) == 0 {
		if tls.eof {
			return 0, os.EOF
		}

		var timeoutChan chan bool
		if tls.readTimeout > 0 {
			timeoutChan = make(chan bool)
			go timeout(timeoutChan, tls.readTimeout)
		}

		select {
		case b := <-tls.readChan:
			tls.readBuf = b
		case <-timeoutChan:
			return 0, os.EAGAIN
		}

		// TLS distinguishes between orderly closes and truncations. An
		// orderly close is represented by a zero length slice.
		if closed(tls.readChan) {
			return 0, io.ErrUnexpectedEOF
		}
		if len(tls.readBuf) == 0 {
			tls.eof = true
			return 0, os.EOF
		}
	}

	n := bytes.Copy(p, tls.readBuf)
	tls.readBuf = tls.readBuf[n:len(tls.readBuf)]
	return n, nil
}

func (r *msgReceiver) recv() (*msg, os.Error) {
	// Init pointers to buffers where syscall recvmsg can write.
	r.iov.base = &r.data[0]
	r.iov.len = int32(len(r.data))
	r.hdr.iov = &r.iov
	r.hdr.niov = 1
	r.hdr.desc = &r.desc[0]
	r.hdr.ndesc = int32(len(r.desc))
	n, _, e := syscall.Syscall(syscall.SYS_IMC_RECVMSG, uintptr(r.fd), uintptr(unsafe.Pointer(&r.hdr)), 0)
	if e != 0 {
		return nil, os.NewSyscallError("imc_recvmsg", int(e))
	}

	// Make a copy of the data so that the next recvmsg doesn't
	// smash it.  The system call did not update r.iov.len.  Instead it
	// returned the total byte count as n.
	m := new(msg)
	m.rdata = make([]byte, n)
	bytes.Copy(m.rdata, &r.data)

	// Make a copy of the desc too.
	// The system call *did* update r.hdr.ndesc.
	if r.hdr.ndesc > 0 {
		m.rdesc = make([]int32, r.hdr.ndesc)
		for i := range m.rdesc {
			m.rdesc[i] = r.desc[i]
		}
	}

	return m, nil
}

func (d *deflater) fillWindow(index int) (int, os.Error) {
	wSize := d.windowMask + 1
	if index >= wSize+wSize-(minMatchLength+maxMatchLength) {
		// shift the window by wSize
		bytes.Copy(d.window, d.window[wSize:2*wSize])
		index -= wSize
		d.windowEnd -= wSize
		if d.blockStart >= wSize {
			d.blockStart -= wSize
		} else {
			d.blockStart = math.MaxInt32
		}
		for i, h := range d.hashHead {
			d.hashHead[i] = max(h-wSize, -1)
		}
		for i, h := range d.hashPrev {
			d.hashPrev[i] = max(h-wSize, -1)
		}
	}
	var count int
	var err os.Error
	count, err = io.ReadAtLeast(d.r, d.window[d.windowEnd:len(d.window)], 1)
	d.windowEnd += count
	if err == os.EOF {
		return index, nil
	}
	return index, err
}

func (d *decoder) Read(p []byte) (n int, err os.Error) {
	if d.err != nil {
		return 0, d.err
	}

	// Use leftover decoded output from last read.
	if len(d.out) > 0 {
		n = bytes.Copy(p, d.out)
		d.out = d.out[n:len(d.out)]
		return n, nil
	}

	// Read a chunk.
	nn := len(p) / 3 * 4
	if nn < 4 {
		nn = 4
	}
	if nn > len(d.buf) {
		nn = len(d.buf)
	}
	nn, d.err = io.ReadAtLeast(d.r, d.buf[d.nbuf:nn], 4-d.nbuf)
	d.nbuf += nn
	if d.nbuf < 4 {
		return 0, d.err
	}

	// Decode chunk into p, or d.out and then p if p is too small.
	nr := d.nbuf / 4 * 4
	nw := d.nbuf / 4 * 3
	if nw > len(p) {
		nw, d.end, d.err = d.enc.decode(&d.outbuf, d.buf[0:nr])
		d.out = d.outbuf[0:nw]
		n = bytes.Copy(p, d.out)
		d.out = d.out[n:len(d.out)]
	} else {
		n, d.end, d.err = d.enc.decode(p, d.buf[0:nr])
	}
	d.nbuf -= nr
	for i := 0; i < d.nbuf; i++ {
		d.buf[i] = d.buf[i+nr]
	}

	if d.err == nil {
		d.err = err
	}
	return n, d.err
}

// pRF11 implements the TLS 1.1 pseudo-random function, as defined in RFC 4346, section 5.
func pRF11(result, secret, label, seed []byte) {
	hashSHA1 := sha1.New()
	hashMD5 := md5.New()

	labelAndSeed := make([]byte, len(label)+len(seed))
	bytes.Copy(labelAndSeed, label)
	bytes.Copy(labelAndSeed[len(label):len(labelAndSeed)], seed)

	s1, s2 := splitPreMasterSecret(secret)
	pHash(result, s1, labelAndSeed, hashMD5)
	result2 := make([]byte, len(result))
	pHash(result2, s2, labelAndSeed, hashSHA1)

	for i, b := range result2 {
		result[i] ^= b
	}
}

func (r *reader) Read(p []byte) (n int, err os.Error) {
	b := *r;
	if len(b) == 0 && len(p) > 0 {
		return 0, os.EOF
	}
	n = bytes.Copy(p, b);
	*r = b[n:len(b)];
	return;
}

// leftPad returns a new slice of length size. The contents of input are right
// aligned in the new slice.
func leftPad(input []byte, size int) (out []byte) {
	n := len(input)
	if n > size {
		n = size
	}
	out = make([]byte, size)
	bytes.Copy(out[len(out)-n:len(out)], input)
	return
}

// keysFromPreMasterSecret generates the connection keys from the pre master
// secret, given the lengths of the MAC and cipher keys, as defined in RFC
// 4346, section 6.3.
func keysFromPreMasterSecret11(preMasterSecret, clientRandom, serverRandom []byte, macLen, keyLen int) (masterSecret, clientMAC, serverMAC, clientKey, serverKey []byte) {
	var seed [tlsRandomLength * 2]byte
	bytes.Copy(seed[0:len(clientRandom)], clientRandom)
	bytes.Copy(seed[len(clientRandom):len(seed)], serverRandom)
	masterSecret = make([]byte, masterSecretLength)
	pRF11(masterSecret, preMasterSecret, masterSecretLabel, seed[0:len(seed)])

	bytes.Copy(seed[0:len(clientRandom)], serverRandom)
	bytes.Copy(seed[len(serverRandom):len(seed)], clientRandom)

	n := 2*macLen + 2*keyLen
	keyMaterial := make([]byte, n)
	pRF11(keyMaterial, masterSecret, keyExpansionLabel, seed[0:len(seed)])
	clientMAC = keyMaterial[0:macLen]
	serverMAC = keyMaterial[macLen : macLen*2]
	clientKey = keyMaterial[macLen*2 : macLen*2+keyLen]
	serverKey = keyMaterial[macLen*2+keyLen : len(keyMaterial)]
	return
}