1 files changed, 265 insertions, 0 deletions
diff --git a/vendor/github.com/klauspost/compress/flate/gen.go b/vendor/github.com/klauspost/compress/flate/gen.go
new file mode 100644
index 000000000..154c89a48
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/flate/gen.go
@@ -0,0 +1,265 @@
+// Copyright 2012 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.
+
+// +build ignore
+
+// This program generates fixedhuff.go
+// Invoke as
+//
+//	go run gen.go -output fixedhuff.go
+
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"go/format"
+	"io/ioutil"
+	"log"
+)
+
+var filename = flag.String("output", "fixedhuff.go", "output file name")
+
+const maxCodeLen = 16
+
+// Note: the definition of the huffmanDecoder struct is copied from
+// inflate.go, as it is private to the implementation.
+
+// chunk & 15 is number of bits
+// chunk >> 4 is value, including table link
+
+const (
+	huffmanChunkBits  = 9
+	huffmanNumChunks  = 1 << huffmanChunkBits
+	huffmanCountMask  = 15
+	huffmanValueShift = 4
+)
+
+type huffmanDecoder struct {
+	min      int                      // the minimum code length
+	chunks   [huffmanNumChunks]uint32 // chunks as described above
+	links    [][]uint32               // overflow links
+	linkMask uint32                   // mask the width of the link table
+}
+
+// Initialize Huffman decoding tables from array of code lengths.
+// Following this function, h is guaranteed to be initialized into a complete
+// tree (i.e., neither over-subscribed nor under-subscribed). The exception is a
+// degenerate case where the tree has only a single symbol with length 1. Empty
+// trees are permitted.
+func (h *huffmanDecoder) init(bits []int) bool {
+	// Sanity enables additional runtime tests during Huffman
+	// table construction.  It's intended to be used during
+	// development to supplement the currently ad-hoc unit tests.
+	const sanity = false
+
+	if h.min != 0 {
+		*h = huffmanDecoder{}
+	}
+
+	// Count number of codes of each length,
+	// compute min and max length.
+	var count [maxCodeLen]int
+	var min, max int
+	for _, n := range bits {
+		if n == 0 {
+			continue
+		}
+		if min == 0 || n < min {
+			min = n
+		}
+		if n > max {
+			max = n
+		}
+		count[n]++
+	}
+
+	// Empty tree. The decompressor.huffSym function will fail later if the tree
+	// is used. Technically, an empty tree is only valid for the HDIST tree and
+	// not the HCLEN and HLIT tree. However, a stream with an empty HCLEN tree
+	// is guaranteed to fail since it will attempt to use the tree to decode the
+	// codes for the HLIT and HDIST trees. Similarly, an empty HLIT tree is
+	// guaranteed to fail later since the compressed data section must be
+	// composed of at least one symbol (the end-of-block marker).
+	if max == 0 {
+		return true
+	}
+
+	code := 0
+	var nextcode [maxCodeLen]int
+	for i := min; i <= max; i++ {
+		code <<= 1
+		nextcode[i] = code
+		code += count[i]
+	}
+
+	// Check that the coding is complete (i.e., that we've
+	// assigned all 2-to-the-max possible bit sequences).
+	// Exception: To be compatible with zlib, we also need to
+	// accept degenerate single-code codings.  See also
+	// TestDegenerateHuffmanCoding.
+	if code != 1<<uint(max) && !(code == 1 && max == 1) {
+		return false
+	}
+
+	h.min = min
+	if max > huffmanChunkBits {
+		numLinks := 1 << (uint(max) - huffmanChunkBits)
+		h.linkMask = uint32(numLinks - 1)
+
+		// create link tables
+		link := nextcode[huffmanChunkBits+1] >> 1
+		h.links = make([][]uint32, huffmanNumChunks-link)
+		for j := uint(link); j < huffmanNumChunks; j++ {
+			reverse := int(reverseByte[j>>8]) | int(reverseByte[j&0xff])<<8
+			reverse >>= uint(16 - huffmanChunkBits)
+			off := j - uint(link)
+			if sanity && h.chunks[reverse] != 0 {
+				panic("impossible: overwriting existing chunk")
+			}
+			h.chunks[reverse] = uint32(off<<huffmanValueShift | (huffmanChunkBits + 1))
+			h.links[off] = make([]uint32, numLinks)
+		}
+	}
+
+	for i, n := range bits {
+		if n == 0 {
+			continue
+		}
+		code := nextcode[n]
+		nextcode[n]++
+		chunk := uint32(i<<huffmanValueShift | n)
+		reverse := int(reverseByte[code>>8]) | int(reverseByte[code&0xff])<<8
+		reverse >>= uint(16 - n)
+		if n <= huffmanChunkBits {
+			for off := reverse; off < len(h.chunks); off += 1 << uint(n) {
+				// We should never need to overwrite
+				// an existing chunk.  Also, 0 is
+				// never a valid chunk, because the
+				// lower 4 "count" bits should be
+				// between 1 and 15.
+				if sanity && h.chunks[off] != 0 {
+					panic("impossible: overwriting existing chunk")
+				}
+				h.chunks[off] = chunk
+			}
+		} else {
+			j := reverse & (huffmanNumChunks - 1)
+			if sanity && h.chunks[j]&huffmanCountMask != huffmanChunkBits+1 {
+				// Longer codes should have been
+				// associated with a link table above.
+				panic("impossible: not an indirect chunk")
+			}
+			value := h.chunks[j] >> huffmanValueShift
+			linktab := h.links[value]
+			reverse >>= huffmanChunkBits
+			for off := reverse; off < len(linktab); off += 1 << uint(n-huffmanChunkBits) {
+				if sanity && linktab[off] != 0 {
+					panic("impossible: overwriting existing chunk")
+				}
+				linktab[off] = chunk
+			}
+		}
+	}
+
+	if sanity {
+		// Above we've sanity checked that we never overwrote
+		// an existing entry.  Here we additionally check that
+		// we filled the tables completely.
+		for i, chunk := range h.chunks {
+			if chunk == 0 {
+				// As an exception, in the degenerate
+				// single-code case, we allow odd
+				// chunks to be missing.
+				if code == 1 && i%2 == 1 {
+					continue
+				}
+				panic("impossible: missing chunk")
+			}
+		}
+		for _, linktab := range h.links {
+			for _, chunk := range linktab {
+				if chunk == 0 {
+					panic("impossible: missing chunk")
+				}
+			}
+		}
+	}
+
+	return true
+}
+
+func main() {
+	flag.Parse()
+
+	var h huffmanDecoder
+	var bits [288]int
+	initReverseByte()
+	for i := 0; i < 144; i++ {
+		bits[i] = 8
+	}
+	for i := 144; i < 256; i++ {
+		bits[i] = 9
+	}
+	for i := 256; i < 280; i++ {
+		bits[i] = 7
+	}
+	for i := 280; i < 288; i++ {
+		bits[i] = 8
+	}
+	h.init(bits[:])
+	if h.links != nil {
+		log.Fatal("Unexpected links table in fixed Huffman decoder")
+	}
+
+	var buf bytes.Buffer
+
+	fmt.Fprintf(&buf, `// Copyright 2013 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.`+"\n\n")
+
+	fmt.Fprintln(&buf, "package flate")
+	fmt.Fprintln(&buf)
+	fmt.Fprintln(&buf, "// autogenerated by go run gen.go -output fixedhuff.go, DO NOT EDIT")
+	fmt.Fprintln(&buf)
+	fmt.Fprintln(&buf, "var fixedHuffmanDecoder = huffmanDecoder{")
+	fmt.Fprintf(&buf, "\t%d,\n", h.min)
+	fmt.Fprintln(&buf, "\t[huffmanNumChunks]uint32{")
+	for i := 0; i < huffmanNumChunks; i++ {
+		if i&7 == 0 {
+			fmt.Fprintf(&buf, "\t\t")
+		} else {
+			fmt.Fprintf(&buf, " ")
+		}
+		fmt.Fprintf(&buf, "0x%04x,", h.chunks[i])
+		if i&7 == 7 {
+			fmt.Fprintln(&buf)
+		}
+	}
+	fmt.Fprintln(&buf, "\t},")
+	fmt.Fprintln(&buf, "\tnil, 0,")
+	fmt.Fprintln(&buf, "}")
+
+	data, err := format.Source(buf.Bytes())
+	if err != nil {
+		log.Fatal(err)
+	}
+	err = ioutil.WriteFile(*filename, data, 0644)
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+var reverseByte [256]byte
+
+func initReverseByte() {
+	for x := 0; x < 256; x++ {
+		var result byte
+		for i := uint(0); i < 8; i++ {
+			result |= byte(((x >> i) & 1) << (7 - i))
+		}
+		reverseByte[x] = result
+	}
+}