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