yenc

Documentation

Index

• func Encode(name string, partNum, total int, begin, end, fileSize int64, data []byte) []byte
• type Part
  • func Decode(r io.Reader) (*Part, error)
  • func DecodeBytes(data []byte) (*Part, error)

Functions

func Encode

func Encode(name string, partNum, total int, begin, end, fileSize int64, data []byte) []byte

Encode produces the raw yEnc article body for one part of a file — the exact inverse of Decode. It is the encoder the download path never needed but the tests do: it lets fixtures build deterministic articles that round-trip through Decode (CRC32 verified) with no real Usenet server.

• name filename advertised in =ybegin (must be last on that line).
• partNum 1-based part number; total the number of parts in the file.
• begin/end 1-based byte offsets of this part within the file (=ypart), inclusive on both ends, so len(data) == end-begin+1.
• fileSize total size of the whole file (=ybegin size=).
• data the raw bytes of THIS part.

When total <= 1 a single-part body (no =ypart, crc32= in =yend) is emitted; otherwise a multipart body (=ypart + pcrc32= in =yend) matching what the streaming OffsetIndex relies on.

Types

type Part

type Part struct {
	Name   string // filename from =ybegin
	Number int    // part number (1-based)
	Total  int    // total parts (from =ybegin total=N)
	Begin  int64  // byte offset start (from =ypart begin=N, 1-based)
	End    int64  // byte offset end (from =ypart end=N, inclusive)
	Size   int64  // total file size (from =ybegin size=N)
	CRC32  uint32 // CRC32 of this part's data (from =yend pcrc32)
	Data   []byte // decoded binary data
}

Part represents a decoded yEnc part (one NNTP article body).

func Decode

func Decode(r io.Reader) (*Part, error)

Decode reads a yEnc encoded article body and returns the decoded part. The reader should contain the raw article body (after NNTP BODY response).

func DecodeBytes

func DecodeBytes(data []byte) (*Part, error)

DecodeBytes decodes a yEnc encoded byte slice.