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path: root/src/pkg/compress/flate/gen.go
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Diffstat (limited to 'src/pkg/compress/flate/gen.go')
-rw-r--r--src/pkg/compress/flate/gen.go165
1 files changed, 0 insertions, 165 deletions
diff --git a/src/pkg/compress/flate/gen.go b/src/pkg/compress/flate/gen.go
deleted file mode 100644
index 1427557f8..000000000
--- a/src/pkg/compress/flate/gen.go
+++ /dev/null
@@ -1,165 +0,0 @@
-// 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 |gofmt >fixedhuff.go
-
-package main
-
-import (
- "fmt"
-)
-
-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.
-func (h *huffmanDecoder) init(bits []int) bool {
- // 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]++
- }
- if max == 0 {
- return false
- }
-
- h.min = min
- var linkBits uint
- var numLinks int
- if max > huffmanChunkBits {
- linkBits = uint(max) - huffmanChunkBits
- numLinks = 1 << linkBits
- h.linkMask = uint32(numLinks - 1)
- }
- code := 0
- var nextcode [maxCodeLen]int
- for i := min; i <= max; i++ {
- if i == huffmanChunkBits+1 {
- // create link tables
- link := code >> 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)
- h.chunks[reverse] = uint32(off<<huffmanValueShift + uint(i))
- h.links[off] = make([]uint32, 1<<linkBits)
- }
- }
- n := count[i]
- nextcode[i] = code
- code += n
- code <<= 1
- }
-
- 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 < huffmanNumChunks; off += 1 << uint(n) {
- h.chunks[off] = chunk
- }
- } else {
- linktab := h.links[h.chunks[reverse&(huffmanNumChunks-1)]>>huffmanValueShift]
- reverse >>= huffmanChunkBits
- for off := reverse; off < numLinks; off += 1 << uint(n-huffmanChunkBits) {
- linktab[off] = chunk
- }
- }
- }
- return true
-}
-
-func main() {
- 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[:])
- fmt.Println("package flate")
- fmt.Println()
- fmt.Println("// autogenerated by gen.go, DO NOT EDIT")
- fmt.Println()
- fmt.Println("var fixedHuffmanDecoder = huffmanDecoder{")
- fmt.Printf("\t%d,\n", h.min)
- fmt.Println("\t[huffmanNumChunks]uint32{")
- for i := 0; i < huffmanNumChunks; i++ {
- if i&7 == 0 {
- fmt.Printf("\t\t")
- } else {
- fmt.Printf(" ")
- }
- fmt.Printf("0x%04x,", h.chunks[i])
- if i&7 == 7 {
- fmt.Println()
- }
- }
- fmt.Println("\t},")
- fmt.Println("\tnil, 0,")
- fmt.Println("}")
-}
-
-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
- }
-}