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author | Wim <wim@42.be> | 2018-08-06 21:47:05 +0200 |
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committer | Wim <wim@42.be> | 2018-08-06 21:47:05 +0200 |
commit | 51062863a5c34d81e296cf15c61140911037cf3b (patch) | |
tree | 9b5e044672486326c7a0ca8fb26430f37bf4d83c /vendor/golang.org/x/net/http2/hpack/huffman.go | |
parent | 4fb4b7aa6c02a54db8ad8dd98e4d321396926c0d (diff) | |
download | matterbridge-msglm-51062863a5c34d81e296cf15c61140911037cf3b.tar.gz matterbridge-msglm-51062863a5c34d81e296cf15c61140911037cf3b.tar.bz2 matterbridge-msglm-51062863a5c34d81e296cf15c61140911037cf3b.zip |
Use mod vendor for vendored directory (backwards compatible)
Diffstat (limited to 'vendor/golang.org/x/net/http2/hpack/huffman.go')
-rw-r--r-- | vendor/golang.org/x/net/http2/hpack/huffman.go | 190 |
1 files changed, 0 insertions, 190 deletions
diff --git a/vendor/golang.org/x/net/http2/hpack/huffman.go b/vendor/golang.org/x/net/http2/hpack/huffman.go deleted file mode 100644 index eb4b1f05..00000000 --- a/vendor/golang.org/x/net/http2/hpack/huffman.go +++ /dev/null @@ -1,190 +0,0 @@ -// Copyright 2014 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -package hpack - -import ( - "bytes" - "errors" - "io" - "sync" -) - -var bufPool = sync.Pool{ - New: func() interface{} { return new(bytes.Buffer) }, -} - -// HuffmanDecode decodes the string in v and writes the expanded -// result to w, returning the number of bytes written to w and the -// Write call's return value. At most one Write call is made. -func HuffmanDecode(w io.Writer, v []byte) (int, error) { - buf := bufPool.Get().(*bytes.Buffer) - buf.Reset() - defer bufPool.Put(buf) - if err := huffmanDecode(buf, 0, v); err != nil { - return 0, err - } - return w.Write(buf.Bytes()) -} - -// HuffmanDecodeToString decodes the string in v. -func HuffmanDecodeToString(v []byte) (string, error) { - buf := bufPool.Get().(*bytes.Buffer) - buf.Reset() - defer bufPool.Put(buf) - if err := huffmanDecode(buf, 0, v); err != nil { - return "", err - } - return buf.String(), nil -} - -// ErrInvalidHuffman is returned for errors found decoding -// Huffman-encoded strings. -var ErrInvalidHuffman = errors.New("hpack: invalid Huffman-encoded data") - -// huffmanDecode decodes v to buf. -// If maxLen is greater than 0, attempts to write more to buf than -// maxLen bytes will return ErrStringLength. -func huffmanDecode(buf *bytes.Buffer, maxLen int, v []byte) error { - n := rootHuffmanNode - cur, nbits := uint(0), uint8(0) - for _, b := range v { - cur = cur<<8 | uint(b) - nbits += 8 - for nbits >= 8 { - idx := byte(cur >> (nbits - 8)) - n = n.children[idx] - if n == nil { - return ErrInvalidHuffman - } - if n.children == nil { - if maxLen != 0 && buf.Len() == maxLen { - return ErrStringLength - } - buf.WriteByte(n.sym) - nbits -= n.codeLen - n = rootHuffmanNode - } else { - nbits -= 8 - } - } - } - for nbits > 0 { - n = n.children[byte(cur<<(8-nbits))] - if n.children != nil || n.codeLen > nbits { - break - } - buf.WriteByte(n.sym) - nbits -= n.codeLen - n = rootHuffmanNode - } - return nil -} - -type node struct { - // children is non-nil for internal nodes - children []*node - - // The following are only valid if children is nil: - codeLen uint8 // number of bits that led to the output of sym - sym byte // output symbol -} - -func newInternalNode() *node { - return &node{children: make([]*node, 256)} -} - -var rootHuffmanNode = newInternalNode() - -func init() { - if len(huffmanCodes) != 256 { - panic("unexpected size") - } - for i, code := range huffmanCodes { - addDecoderNode(byte(i), code, huffmanCodeLen[i]) - } -} - -func addDecoderNode(sym byte, code uint32, codeLen uint8) { - cur := rootHuffmanNode - for codeLen > 8 { - codeLen -= 8 - i := uint8(code >> codeLen) - if cur.children[i] == nil { - cur.children[i] = newInternalNode() - } - cur = cur.children[i] - } - shift := 8 - codeLen - start, end := int(uint8(code<<shift)), int(1<<shift) - for i := start; i < start+end; i++ { - cur.children[i] = &node{sym: sym, codeLen: codeLen} - } -} - -// AppendHuffmanString appends s, as encoded in Huffman codes, to dst -// and returns the extended buffer. -func AppendHuffmanString(dst []byte, s string) []byte { - rembits := uint8(8) - - for i := 0; i < len(s); i++ { - if rembits == 8 { - dst = append(dst, 0) - } - dst, rembits = appendByteToHuffmanCode(dst, rembits, s[i]) - } - - if rembits < 8 { - // special EOS symbol - code := uint32(0x3fffffff) - nbits := uint8(30) - - t := uint8(code >> (nbits - rembits)) - dst[len(dst)-1] |= t - } - - return dst -} - -// HuffmanEncodeLength returns the number of bytes required to encode -// s in Huffman codes. The result is round up to byte boundary. -func HuffmanEncodeLength(s string) uint64 { - n := uint64(0) - for i := 0; i < len(s); i++ { - n += uint64(huffmanCodeLen[s[i]]) - } - return (n + 7) / 8 -} - -// appendByteToHuffmanCode appends Huffman code for c to dst and -// returns the extended buffer and the remaining bits in the last -// element. The appending is not byte aligned and the remaining bits -// in the last element of dst is given in rembits. -func appendByteToHuffmanCode(dst []byte, rembits uint8, c byte) ([]byte, uint8) { - code := huffmanCodes[c] - nbits := huffmanCodeLen[c] - - for { - if rembits > nbits { - t := uint8(code << (rembits - nbits)) - dst[len(dst)-1] |= t - rembits -= nbits - break - } - - t := uint8(code >> (nbits - rembits)) - dst[len(dst)-1] |= t - - nbits -= rembits - rembits = 8 - - if nbits == 0 { - break - } - - dst = append(dst, 0) - } - - return dst, rembits -} |