1 // Copyright 2011 The Snappy-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 snappy
6 7 import (
8 "io"
9 10 "github.com/klauspost/compress/s2"
11 )
12 13 // Encode returns the encoded form of src. The returned slice may be a sub-
14 // slice of dst if dst was large enough to hold the entire encoded block.
15 // Otherwise, a newly allocated slice will be returned.
16 //
17 // The dst and src must not overlap. It is valid to pass a nil dst.
18 //
19 // Encode handles the Snappy block format, not the Snappy stream format.
20 func Encode(dst, src []byte) []byte {
21 return s2.EncodeSnappyBetter(dst, src)
22 }
23 24 // MaxEncodedLen returns the maximum length of a snappy block, given its
25 // uncompressed length.
26 //
27 // It will return a negative value if srcLen is too large to encode.
28 func MaxEncodedLen(srcLen int) int {
29 return s2.MaxEncodedLen(srcLen)
30 }
31 32 // NewWriter returns a new Writer that compresses to w.
33 //
34 // The Writer returned does not buffer writes. There is no need to Flush or
35 // Close such a Writer.
36 //
37 // Deprecated: the Writer returned is not suitable for many small writes, only
38 // for few large writes. Use NewBufferedWriter instead, which is efficient
39 // regardless of the frequency and shape of the writes, and remember to Close
40 // that Writer when done.
41 func NewWriter(w io.Writer) *Writer {
42 return s2.NewWriter(w, s2.WriterSnappyCompat(), s2.WriterBetterCompression(), s2.WriterFlushOnWrite(), s2.WriterConcurrency(1))
43 }
44 45 // NewBufferedWriter returns a new Writer that compresses to w, using the
46 // framing format described at
47 // https://github.com/google/snappy/blob/master/framing_format.txt
48 //
49 // The Writer returned buffers writes. Users must call Close to guarantee all
50 // data has been forwarded to the underlying io.Writer. They may also call
51 // Flush zero or more times before calling Close.
52 func NewBufferedWriter(w io.Writer) *Writer {
53 return s2.NewWriter(w, s2.WriterSnappyCompat(), s2.WriterBetterCompression())
54 }
55 56 // Writer is an io.Writer that can write Snappy-compressed bytes.
57 //
58 // Writer handles the Snappy stream format, not the Snappy block format.
59 type Writer = s2.Writer
60