diff options
Diffstat (limited to 'formats/packp/pktline/encoder.go')
-rw-r--r-- | formats/packp/pktline/encoder.go | 123 |
1 files changed, 0 insertions, 123 deletions
diff --git a/formats/packp/pktline/encoder.go b/formats/packp/pktline/encoder.go deleted file mode 100644 index 0a88a9b..0000000 --- a/formats/packp/pktline/encoder.go +++ /dev/null @@ -1,123 +0,0 @@ -// Package pktline implements reading payloads form pkt-lines and encoding pkt-lines from payloads. -package pktline - -import ( - "bytes" - "errors" - "fmt" - "io" -) - -// An Encoder writes pkt-lines to an output stream. -type Encoder struct { - w io.Writer -} - -const ( - // MaxPayloadSize is the maximum payload size of a pkt-line in bytes. - MaxPayloadSize = 65516 -) - -var ( - // FlushPkt are the contents of a flush-pkt pkt-line. - FlushPkt = []byte{'0', '0', '0', '0'} - // Flush is the payload to use with the Encode method to encode a flush-pkt. - Flush = []byte{} - // FlushString is the payload to use with the EncodeString method to encode a flush-pkt. - FlushString = "" - // ErrPayloadTooLong is returned by the Encode methods when any of the - // provided payloads is bigger than MaxPayloadSize. - ErrPayloadTooLong = errors.New("payload is too long") -) - -// NewEncoder returns a new encoder that writes to w. -func NewEncoder(w io.Writer) *Encoder { - return &Encoder{ - w: w, - } -} - -// Flush encodes a flush-pkt to the output stream. -func (e *Encoder) Flush() error { - _, err := e.w.Write(FlushPkt) - return err -} - -// Encode encodes a pkt-line with the payload specified and write it to -// the output stream. If several payloads are specified, each of them -// will get streamed in their own pkt-lines. -func (e *Encoder) Encode(payloads ...[]byte) error { - for _, p := range payloads { - if err := e.encodeLine(p); err != nil { - return err - } - } - - return nil -} - -func (e *Encoder) encodeLine(p []byte) error { - if len(p) > MaxPayloadSize { - return ErrPayloadTooLong - } - - if bytes.Equal(p, Flush) { - if err := e.Flush(); err != nil { - return err - } - return nil - } - - n := len(p) + 4 - if _, err := e.w.Write(asciiHex16(n)); err != nil { - return err - } - if _, err := e.w.Write(p); err != nil { - return err - } - - return nil -} - -// Returns the hexadecimal ascii representation of the 16 less -// significant bits of n. The length of the returned slice will always -// be 4. Example: if n is 1234 (0x4d2), the return value will be -// []byte{'0', '4', 'd', '2'}. -func asciiHex16(n int) []byte { - var ret [4]byte - ret[0] = byteToASCIIHex(byte(n & 0xf000 >> 12)) - ret[1] = byteToASCIIHex(byte(n & 0x0f00 >> 8)) - ret[2] = byteToASCIIHex(byte(n & 0x00f0 >> 4)) - ret[3] = byteToASCIIHex(byte(n & 0x000f)) - - return ret[:] -} - -// turns a byte into its hexadecimal ascii representation. Example: -// from 11 (0xb) to 'b'. -func byteToASCIIHex(n byte) byte { - if n < 10 { - return '0' + n - } - - return 'a' - 10 + n -} - -// EncodeString works similarly as Encode but payloads are specified as strings. -func (e *Encoder) EncodeString(payloads ...string) error { - for _, p := range payloads { - if err := e.Encode([]byte(p)); err != nil { - return err - } - } - - return nil -} - -// Encodef encodes a single pkt-line with the payload formatted as -// the format specifier and the rest of the arguments suggest. -func (e *Encoder) Encodef(format string, a ...interface{}) error { - return e.EncodeString( - fmt.Sprintf(format, a...), - ) -} |