diff options
Diffstat (limited to 'vendor/golang.org/x/net/http2/hpack/huffman.go')
| -rw-r--r-- | vendor/golang.org/x/net/http2/hpack/huffman.go | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/vendor/golang.org/x/net/http2/hpack/huffman.go b/vendor/golang.org/x/net/http2/hpack/huffman.go index 8850e39..b412a96 100644 --- a/vendor/golang.org/x/net/http2/hpack/huffman.go +++ b/vendor/golang.org/x/net/http2/hpack/huffman.go @@ -47,6 +47,7 @@ var ErrInvalidHuffman = errors.New("hpack: invalid Huffman-encoded data") // 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 { + rootHuffmanNode := getRootHuffmanNode() n := rootHuffmanNode // cur is the bit buffer that has not been fed into n. // cbits is the number of low order bits in cur that are valid. @@ -106,7 +107,7 @@ func huffmanDecode(buf *bytes.Buffer, maxLen int, v []byte) error { type node struct { // children is non-nil for internal nodes - children []*node + children *[256]*node // The following are only valid if children is nil: codeLen uint8 // number of bits that led to the output of sym @@ -114,22 +115,31 @@ type node struct { } func newInternalNode() *node { - return &node{children: make([]*node, 256)} + return &node{children: new([256]*node)} } -var rootHuffmanNode = newInternalNode() +var ( + buildRootOnce sync.Once + lazyRootHuffmanNode *node +) + +func getRootHuffmanNode() *node { + buildRootOnce.Do(buildRootHuffmanNode) + return lazyRootHuffmanNode +} -func init() { +func buildRootHuffmanNode() { if len(huffmanCodes) != 256 { panic("unexpected size") } + lazyRootHuffmanNode = newInternalNode() for i, code := range huffmanCodes { addDecoderNode(byte(i), code, huffmanCodeLen[i]) } } func addDecoderNode(sym byte, code uint32, codeLen uint8) { - cur := rootHuffmanNode + cur := lazyRootHuffmanNode for codeLen > 8 { codeLen -= 8 i := uint8(code >> codeLen) |