| // Copyright 2018 The Wuffs Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| // +build ignore |
| |
| package main |
| |
| // make-deflate.go makes some data in the deflate format. |
| // |
| // See test/data/artificial/*.deflate.make.txt for examples. |
| // |
| // Usage: go run make-deflate.go < foo.make.txt |
| |
| import ( |
| "fmt" |
| "io/ioutil" |
| "os" |
| "strconv" |
| "strings" |
| ) |
| |
| // Global state. |
| var ( |
| block uint32 |
| bncData []byte |
| repeats []repeat |
| stream bitStream |
| ) |
| |
| const ( |
| blockZero = 0 |
| blockNoCompression = 1 |
| blockFixedHuffman = 2 |
| // TODO: blockDynamicHuffman. |
| ) |
| |
| var doFuncs = [...]func(s string) error{ |
| blockZero: doBlockZero, |
| blockNoCompression: doBlockNoCompression, |
| blockFixedHuffman: doBlockFixedHuffman, |
| } |
| |
| type bitStream struct { |
| buf []byte |
| bits uint32 |
| nBits uint32 // Always within [0, 7]. |
| } |
| |
| // writeBits writes the low n bits of b to z. |
| func (z *bitStream) writeBits(b uint32, n uint32) { |
| if n > 24 { |
| panic("writeBits: n is too large") |
| } |
| z.bits |= b << z.nBits |
| z.nBits += n |
| for z.nBits >= 8 { |
| z.buf = append(z.buf, uint8(z.bits)) |
| z.bits >>= 8 |
| z.nBits -= 8 |
| } |
| } |
| |
| func (z *bitStream) writeBytes(b []byte) { |
| z.flush() |
| z.buf = append(z.buf, b...) |
| } |
| |
| func (z *bitStream) writeLCode(lCode uint32) { |
| switch { |
| case lCode < 144: // 0b._0011_0000 through 0b._1011_1111 |
| lCode += 0x030 |
| z.writeBits(reverse(lCode, 8), 8) |
| case lCode < 256: // 0b1_1001_0000 through 0b1_1111_1111 |
| lCode += 0x190 - 144 |
| z.writeBits(reverse(lCode, 9), 9) |
| case lCode < 280: // 0b._.000_0000 through 0b._.001_0111 |
| lCode -= 256 - 0x000 |
| z.writeBits(reverse(lCode, 7), 7) |
| default: // 0b._1100_0000 through 0b._1100_0111 |
| lCode -= 280 - 0x0C0 |
| z.writeBits(reverse(lCode, 8), 8) |
| } |
| } |
| |
| func (z *bitStream) flush() { |
| if z.nBits > 0 { |
| z.buf = append(z.buf, uint8(z.bits)) |
| z.bits = 0 |
| z.nBits = 0 |
| } |
| } |
| |
| type repeat struct { |
| count uint32 |
| remaining string |
| } |
| |
| func main() { |
| if err := main1(); err != nil { |
| os.Stderr.WriteString(err.Error() + "\n") |
| os.Exit(1) |
| } |
| } |
| |
| func main1() error { |
| stdin, err := ioutil.ReadAll(os.Stdin) |
| if err != nil { |
| return err |
| } |
| s := string(stdin) |
| for remaining := ""; len(s) > 0; s, remaining = remaining, "" { |
| if i := strings.IndexByte(s, '\n'); i >= 0 { |
| s, remaining = s[:i], s[i+1:] |
| } |
| s = strings.TrimSpace(s) |
| if s == "" || s[0] == '#' { |
| continue |
| } |
| |
| const rep = "repeat " |
| if strings.HasPrefix(s, rep) { |
| args := s[len(rep):] |
| count, args, ok := parseNum(args) |
| if !ok || count <= 0 || args != "[" { |
| return fmt.Errorf("bad repeat command: %q", s) |
| } |
| repeats = append(repeats, repeat{ |
| count: count, |
| remaining: remaining, |
| }) |
| continue |
| } |
| |
| if s == "]" { |
| if len(repeats) <= 0 { |
| return fmt.Errorf(`unbalanced close-repeat command: "]"`) |
| } |
| i := len(repeats) - 1 |
| repeats[i].count-- |
| if repeats[i].count == 0 { |
| repeats = repeats[:i] |
| } else { |
| remaining = repeats[i].remaining |
| } |
| continue |
| } |
| |
| if err := doFuncs[block](s); err != nil { |
| return err |
| } |
| } |
| |
| stream.flush() |
| _, err = os.Stdout.Write(stream.buf) |
| return err |
| } |
| |
| func doBlockZero(line string) error { |
| const ( |
| bnc = "blockNoCompression " |
| bfh = "blockFixedHuffman " |
| ) |
| bits := uint32(0) |
| s := "" |
| |
| switch { |
| case strings.HasPrefix(line, bnc): |
| s = line[len(bnc):] |
| block = blockNoCompression |
| bits |= 0 << 1 |
| case strings.HasPrefix(line, bfh): |
| s = line[len(bfh):] |
| block = blockFixedHuffman |
| bits |= 1 << 1 |
| default: |
| return fmt.Errorf("bad blockZero command: %q", line) |
| } |
| |
| switch s { |
| case "(final) {": |
| bits |= 1 |
| case "(nonFinal) {": |
| // No-op. |
| default: |
| return fmt.Errorf("bad blockZero command: %q", line) |
| } |
| |
| stream.writeBits(bits, 3) |
| return nil |
| } |
| |
| func doBlockNoCompression(line string) error { |
| if line == "}" { |
| if len(bncData) > 0xFFFF { |
| return fmt.Errorf("bncData is too long") |
| } |
| n := uint32(len(bncData)) |
| stream.flush() |
| stream.writeBits(n, 16) |
| stream.writeBits(0xFFFF-n, 16) |
| stream.writeBytes(bncData) |
| bncData = bncData[:0] |
| block = blockZero |
| return nil |
| } |
| |
| if lit, ok := parseLiteral(line); ok { |
| bncData = append(bncData, lit...) |
| return nil |
| } |
| |
| return fmt.Errorf("bad blockNoCompression command: %q", line) |
| } |
| |
| func doBlockFixedHuffman(line string) error { |
| if line == "}" { |
| block = blockZero |
| return nil |
| } |
| |
| if line == "endOfBlock" { |
| stream.writeBits(0, 7) |
| return nil |
| } |
| |
| if lit, ok := parseLiteral(line); ok { |
| // TODO: support "\xAB" escape codes in the script? |
| for i := 0; i < len(lit); i++ { |
| stream.writeLCode(uint32(lit[i])) |
| } |
| return nil |
| } |
| |
| if l, d, ok := parseLenDist(line); ok { |
| lCode, lExtra, lNExtra := encodeLength(l) |
| stream.writeLCode(lCode) |
| stream.writeBits(lExtra, lNExtra) |
| dCode, dExtra, dNExtra := encodeDistance(d) |
| stream.writeBits(reverse(dCode, 5), 5) |
| stream.writeBits(dExtra, dNExtra) |
| return nil |
| } |
| |
| return fmt.Errorf("bad blockFixedHuffman command: %q", line) |
| } |
| |
| func encodeLength(l uint32) (code uint32, extra uint32, nExtra uint32) { |
| switch { |
| case l < 3: |
| // No-op. |
| case l < 11: |
| l -= 3 |
| return (l >> 0) + 257, l & 0x0000, 0 |
| case l < 19: |
| l -= 11 |
| return (l >> 1) + 265, l & 0x0001, 1 |
| case l < 35: |
| l -= 19 |
| return (l >> 2) + 269, l & 0x0003, 2 |
| case l < 67: |
| l -= 35 |
| return (l >> 3) + 273, l & 0x0007, 3 |
| case l < 131: |
| l -= 67 |
| return (l >> 4) + 277, l & 0x000F, 4 |
| case l < 258: |
| l -= 131 |
| return (l >> 5) + 281, l & 0x001F, 5 |
| case l == 258: |
| return 285, 0, 0 |
| } |
| panic(fmt.Sprintf("encodeLength: l=%d", l)) |
| } |
| |
| func encodeDistance(d uint32) (code uint32, extra uint32, nExtra uint32) { |
| switch { |
| case d < 1: |
| // No-op. |
| case d < 5: |
| d -= 1 |
| return (d >> 0) + 0, d & 0x0000, 0 |
| case d < 9: |
| d -= 5 |
| return (d >> 1) + 4, d & 0x0001, 1 |
| case d < 17: |
| d -= 9 |
| return (d >> 2) + 6, d & 0x0003, 2 |
| case d < 33: |
| d -= 17 |
| return (d >> 3) + 8, d & 0x0007, 3 |
| case d < 65: |
| d -= 33 |
| return (d >> 4) + 10, d & 0x000F, 4 |
| case d < 129: |
| d -= 65 |
| return (d >> 5) + 12, d & 0x001F, 5 |
| case d < 257: |
| d -= 129 |
| return (d >> 6) + 14, d & 0x003F, 6 |
| case d < 513: |
| d -= 257 |
| return (d >> 7) + 16, d & 0x007F, 7 |
| case d < 1025: |
| d -= 513 |
| return (d >> 8) + 18, d & 0x00FF, 8 |
| case d < 2049: |
| d -= 1025 |
| return (d >> 9) + 20, d & 0x01FF, 9 |
| case d < 4097: |
| d -= 2049 |
| return (d >> 10) + 22, d & 0x03FF, 10 |
| case d < 8193: |
| d -= 4097 |
| return (d >> 11) + 24, d & 0x07FF, 11 |
| case d < 16385: |
| d -= 8193 |
| return (d >> 12) + 26, d & 0x0FFF, 12 |
| case d < 32769: |
| d -= 16385 |
| return (d >> 13) + 28, d & 0x1FFF, 13 |
| } |
| panic(fmt.Sprintf("encodeDistance: d=%d", d)) |
| } |
| |
| func reverse(x uint32, n uint32) uint32 { |
| x = uint32(reverse8[0xFF&(x>>0)])<<24 | |
| uint32(reverse8[0xFF&(x>>8)])<<16 | |
| uint32(reverse8[0xFF&(x>>16)])<<8 | |
| uint32(reverse8[0xFF&(x>>24)])<<0 |
| return x >> (32 - n) |
| } |
| |
| var reverse8 = [256]byte{ |
| 0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, // 0x00 - 0x07 |
| 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0, // 0x08 - 0x0F |
| 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8, // 0x10 - 0x17 |
| 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8, // 0x18 - 0x1F |
| 0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4, // 0x20 - 0x27 |
| 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4, // 0x28 - 0x2F |
| 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC, // 0x30 - 0x37 |
| 0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC, // 0x38 - 0x3F |
| 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2, // 0x40 - 0x47 |
| 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2, // 0x48 - 0x4F |
| 0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA, // 0x50 - 0x57 |
| 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA, // 0x58 - 0x5F |
| 0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6, // 0x60 - 0x67 |
| 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6, // 0x68 - 0x6F |
| 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE, // 0x70 - 0x77 |
| 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE, // 0x78 - 0x7F |
| 0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1, // 0x80 - 0x87 |
| 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1, // 0x88 - 0x8F |
| 0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9, // 0x90 - 0x97 |
| 0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9, // 0x98 - 0x9F |
| 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5, // 0xA0 - 0xA7 |
| 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5, // 0xA8 - 0xAF |
| 0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED, // 0xB0 - 0xB7 |
| 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD, // 0xB8 - 0xBF |
| 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3, // 0xC0 - 0xC7 |
| 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3, // 0xC8 - 0xCF |
| 0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB, // 0xD0 - 0xD7 |
| 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB, // 0xD8 - 0xDF |
| 0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7, // 0xE0 - 0xE7 |
| 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7, // 0xE8 - 0xEF |
| 0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF, // 0xF0 - 0xF7 |
| 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF, // 0xF8 - 0xFF |
| } |
| |
| func parseLiteral(s string) (lit string, ok bool) { |
| const ( |
| prefix = `literal "` |
| suffix = `"` |
| ) |
| if strings.HasPrefix(s, prefix) { |
| s = s[len(prefix):] |
| if strings.HasSuffix(s, suffix) { |
| return s[:len(s)-len(suffix)], true |
| } |
| } |
| return "", false |
| } |
| |
| func parseLenDist(line string) (l uint32, d uint32, ok bool) { |
| const ( |
| lStr = "len " |
| dStr = "dist " |
| ) |
| s := line |
| if strings.HasPrefix(s, lStr) { |
| s = s[len(lStr):] |
| if l, s, ok := parseNum(s); ok && 3 <= l && l <= 258 { |
| if strings.HasPrefix(s, dStr) { |
| s = s[len(dStr):] |
| if d, s, ok := parseNum(s); ok && 1 <= d && d <= 32768 && s == "" { |
| return l, d, true |
| } |
| } |
| } |
| } |
| return 0, 0, false |
| } |
| |
| func parseNum(s string) (num uint32, remaining string, ok bool) { |
| if i := strings.IndexByte(s, ' '); i >= 0 { |
| s, remaining = s[:i], s[i+1:] |
| for len(remaining) > 0 && remaining[0] == ' ' { |
| remaining = remaining[1:] |
| } |
| } |
| |
| u, err := strconv.ParseUint(s, 10, 32) |
| if err != nil { |
| return 0, "", false |
| } |
| return uint32(u), remaining, true |
| } |
