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// 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-artificial.go makes test data in various formats.
//
// See test/data/artificial/*.make.txt for examples.
//
// Usage: go run make-artificial.go < foo.make.txt
import (
"bytes"
"compress/lzw"
"fmt"
"io/ioutil"
"os"
"strconv"
"strings"
)
type stateFunc func(line string) (stateFunc, error)
type repeat struct {
count uint32
remaining string
}
var (
state stateFunc
repeats []repeat
out []byte
formats = map[string]stateFunc{}
)
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
}
if state == nil {
const m = "make "
if !strings.HasPrefix(s, m) {
return fmt.Errorf(`input must start with "make foo"`)
}
s = s[len(m):]
state = formats[s]
if state == nil {
return fmt.Errorf("unsupported format %q", s)
}
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
}
state, err = state(s)
if err != nil {
return err
}
if state == nil {
return fmt.Errorf("bad state transition")
}
}
if state == nil {
return fmt.Errorf("no 'make' line")
} else {
state, err = state("")
if err != nil {
return err
}
}
_, err = os.Stdout.Write(out)
return err
}
// ----
func appendU16LE(b []byte, u uint16) []byte {
return append(b, uint8(u), uint8(u>>8))
}
func log2(u uint32) (i int32) {
for i, pow := uint32(0), uint32(1); i < 32; i, pow = i+1, pow<<1 {
if u == pow {
return int32(i)
}
if u < pow {
break
}
}
return -1
}
func parseHex(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:]
}
}
if len(s) < 2 || s[0] != '0' || s[1] != 'x' {
return 0, "", false
}
s = s[2:]
u, err := strconv.ParseUint(s, 16, 32)
if err != nil {
return 0, "", false
}
return uint32(u), remaining, true
}
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
}
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 init() {
formats["deflate"] = stateDeflate
}
var deflateCodeOrder = [19]uint32{
16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15,
}
type deflateHuffmanTable map[uint32]string
var deflateGlobals struct {
bncData []byte
stream deflateBitStream
// Dynamic Huffman state.
whichHuffman uint32
// 0=Unused, 1=CodeLength, 2=Literal/Length, 3=Distance.
huffmans [4]deflateHuffmanTable
// DHH (Dynamic Huffman, inside a Huffman table) state.
prevLine string
etcetera bool
}
func deflateGlobalsClearDynamicHuffmanState() {
deflateGlobals.whichHuffman = 0
deflateGlobals.huffmans = [4]deflateHuffmanTable{}
deflateGlobals.prevLine = ""
deflateGlobals.etcetera = false
}
func deflateGlobalsCountCodes() (numLCodes uint32, numDCodes uint32, numCLCodeLengths uint32, retErr error) {
for k := range deflateGlobals.huffmans[2] {
if numLCodes < (k + 1) {
numLCodes = (k + 1)
}
}
for k := range deflateGlobals.huffmans[3] {
if numDCodes < (k + 1) {
numDCodes = (k + 1)
}
}
for k := range deflateGlobals.huffmans[1] {
if (k < 0) || (18 < k) {
return 0, 0, 0, fmt.Errorf("bad CodeLength: %d", k)
}
}
for i := len(deflateCodeOrder) - 1; i >= 0; i-- {
cl := deflateCodeOrder[i]
if _, ok := deflateGlobals.huffmans[1][cl]; ok {
numCLCodeLengths = uint32(i + 1)
break
}
}
if numCLCodeLengths < 4 {
numCLCodeLengths = 4
}
return numLCodes, numDCodes, numCLCodeLengths, nil
}
func deflateGlobalsWriteDynamicHuffmanTables() error {
g := &deflateGlobals
numLCodes, numDCodes, numCLCodeLengths, err := deflateGlobalsCountCodes()
if err != nil {
return err
}
if (numLCodes < 257) || (257+31 < numLCodes) {
return fmt.Errorf("bad numLCodes: %d", numLCodes)
}
g.stream.writeBits(numLCodes-257, 5)
if (numDCodes < 1) || (1+31 < numDCodes) {
return fmt.Errorf("bad numDCodes: %d", numDCodes)
}
g.stream.writeBits(numDCodes-1, 5)
if (numCLCodeLengths < 4) || (4+15 < numCLCodeLengths) {
return fmt.Errorf("bad numCLCodeLengths: %d", numCLCodeLengths)
}
g.stream.writeBits(numCLCodeLengths-4, 4)
// Write the Huffman table for CodeLength.
{
for i := uint32(0); i < numCLCodeLengths; i++ {
n := len(g.huffmans[1][deflateCodeOrder[i]])
g.stream.writeBits(uint32(n), 3)
}
for i := numCLCodeLengths; i < uint32(len(deflateCodeOrder)); i++ {
n := len(g.huffmans[1][deflateCodeOrder[i]])
if n > 0 {
return fmt.Errorf("short numCLCodeLengths: %d", numCLCodeLengths)
}
}
}
// Write the Huffman tables for Literal/Length and Distance.
{
numZeroes := uint32(0)
for i := uint32(0); i < numLCodes+numDCodes; i++ {
codeLen := uint32(0)
if i < numLCodes {
codeLen = uint32(len(g.huffmans[2][i]))
} else {
codeLen = uint32(len(g.huffmans[3][i-numLCodes]))
}
if codeLen == 0 {
numZeroes++
continue
}
if err := deflateGlobalsWriteDynamicHuffmanZeroes(numZeroes); err != nil {
return err
}
numZeroes = 0
codeLenCode := g.huffmans[1][codeLen]
if codeLenCode == "" {
return fmt.Errorf("no code for code-length %d", codeLen)
}
deflateGlobalsWriteDynamicHuffmanBits(g.huffmans[1][codeLen])
}
if err := deflateGlobalsWriteDynamicHuffmanZeroes(numZeroes); err != nil {
return err
}
}
return nil
}
func deflateGlobalsWriteDynamicHuffmanZeroes(numZeroes uint32) error {
g := &deflateGlobals
if numZeroes == 0 {
return nil
}
if s := g.huffmans[1][18]; s != "" {
for numZeroes >= 11 {
extra := numZeroes - 11
if extra > 127 {
extra = 127
}
deflateGlobalsWriteDynamicHuffmanBits(s)
g.stream.writeBits(extra, 7)
numZeroes -= 11 + extra
}
}
if s := g.huffmans[1][17]; s != "" {
for numZeroes >= 3 {
extra := numZeroes - 3
if extra > 7 {
extra = 7
}
deflateGlobalsWriteDynamicHuffmanBits(s)
g.stream.writeBits(extra, 3)
numZeroes -= 3 + extra
}
}
if s := g.huffmans[1][0]; s != "" {
for ; numZeroes > 0; numZeroes-- {
deflateGlobalsWriteDynamicHuffmanBits(s)
}
}
if numZeroes > 0 {
return fmt.Errorf("could not write a run of zero-valued code lengths")
}
return nil
}
func deflateGlobalsWriteDynamicHuffmanBits(s string) {
g := &deflateGlobals
for i := 0; i < len(s); i++ {
g.stream.writeBits(uint32(s[i]&1), 1)
}
}
func parseDeflateWhichHuffman(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:]
}
}
switch s {
case "CodeLength":
return 1, remaining, true
case "Literal/Length":
return 2, remaining, true
case "Distance":
return 3, remaining, true
}
return 0, "", false
}
func stateDeflate(line string) (stateFunc, error) {
g := &deflateGlobals
const (
cmdB = "bytes "
cmdBDH = "blockDynamicHuffman "
cmdBFH = "blockFixedHuffman "
cmdBNC = "blockNoCompression "
)
bits := uint32(0)
s := ""
retState := stateFunc(nil)
switch {
case line == "":
g.stream.flush()
return stateDeflate, nil
case strings.HasPrefix(line, cmdB):
s := line[len(cmdB):]
for s != "" {
x, ok := uint32(0), false
x, s, ok = parseHex(s)
if !ok {
return nil, fmt.Errorf("bad stateDeflate command: %q", line)
}
out = append(out, uint8(x))
}
return stateDeflate, nil
case strings.HasPrefix(line, cmdBNC):
s = line[len(cmdBNC):]
retState = stateDeflateNoCompression
bits |= 0 << 1
case strings.HasPrefix(line, cmdBFH):
s = line[len(cmdBFH):]
retState = stateDeflateFixedHuffman
bits |= 1 << 1
case strings.HasPrefix(line, cmdBDH):
s = line[len(cmdBDH):]
retState = stateDeflateDynamicHuffman
bits |= 2 << 1
default:
return nil, fmt.Errorf("bad stateDeflate command: %q", line)
}
switch s {
case "(final) {":
bits |= 1
case "(nonFinal) {":
// No-op.
default:
return nil, fmt.Errorf("bad stateDeflate command: %q", line)
}
g.stream.writeBits(bits, 3)
return retState, nil
}
func stateDeflateNoCompression(line string) (stateFunc, error) {
g := &deflateGlobals
if line == "}" {
if len(g.bncData) > 0xFFFF {
return nil, fmt.Errorf("bncData is too long")
}
n := uint32(len(g.bncData))
g.stream.flush()
g.stream.writeBits(n, 16)
g.stream.writeBits(0xFFFF-n, 16)
g.stream.writeBytes(g.bncData)
g.bncData = g.bncData[:0]
return stateDeflate, nil
}
if lit, ok := deflateParseLiteral(line); ok {
g.bncData = append(g.bncData, lit...)
return stateDeflateNoCompression, nil
}
return nil, fmt.Errorf("bad blockNoCompression command: %q", line)
}
func stateDeflateFixedHuffman(line string) (stateFunc, error) {
g := &deflateGlobals
if line == "}" {
return stateDeflate, nil
}
if line == "endOfBlock" {
g.stream.writeBits(0, 7)
return stateDeflateFixedHuffman, nil
}
if lit, ok := deflateParseLiteral(line); ok {
for i := 0; i < len(lit); i++ {
g.stream.writeFixedHuffmanLCode(uint32(lit[i]))
}
return stateDeflateFixedHuffman, nil
}
if line == "len 3 distCode 31" {
lCode, lExtra, lNExtra := deflateEncodeLength(3)
g.stream.writeFixedHuffmanLCode(lCode)
g.stream.writeBits(lExtra, lNExtra)
dCode, dExtra, dNExtra := uint32(31), uint32(0), uint32(0)
g.stream.writeBits(reverse(dCode, 5), 5)
g.stream.writeBits(dExtra, dNExtra)
return stateDeflateFixedHuffman, nil
}
if l, d, ok := deflateParseLenDist(line); ok {
lCode, lExtra, lNExtra := deflateEncodeLength(l)
g.stream.writeFixedHuffmanLCode(lCode)
g.stream.writeBits(lExtra, lNExtra)
dCode, dExtra, dNExtra := deflateEncodeDistance(d)
g.stream.writeBits(reverse(dCode, 5), 5)
g.stream.writeBits(dExtra, dNExtra)
return stateDeflateFixedHuffman, nil
}
return nil, fmt.Errorf("bad stateDeflateFixedHuffman command: %q", line)
}
func stateDeflateDynamicHuffman(line string) (stateFunc, error) {
g := &deflateGlobals
const (
cmdH = "huffman "
)
switch {
case line == "}":
deflateGlobalsClearDynamicHuffmanState()
return stateDeflate, nil
case strings.HasPrefix(line, cmdH):
s := line[len(cmdH):]
n, s, ok := parseDeflateWhichHuffman(s)
if !ok {
break
}
g.whichHuffman = n
return stateDeflateDynamicHuffmanHuffman, nil
}
if lit, ok := deflateParseLiteral(line); ok {
for i := 0; i < len(lit); i++ {
s := g.huffmans[2][uint32(lit[i])]
if s == "" {
return nil, fmt.Errorf("no code for literal %q (%d)", lit[i:i+1], lit[i])
}
deflateGlobalsWriteDynamicHuffmanBits(s)
}
return stateDeflateDynamicHuffman, nil
} else if l, d, ok := deflateParseLenDist(line); ok {
if (l != 3) || (d != 2) {
return nil, fmt.Errorf("TODO: support len/dist pairs for dynamic Huffman blocks")
}
// len 3 is code 257, with no extra bits.
if s := g.huffmans[2][257]; s != "" {
deflateGlobalsWriteDynamicHuffmanBits(s)
} else {
return nil, fmt.Errorf("no code for literal/length symbol 257")
}
// dist 2 is code 1, with no extra bits.
if s := g.huffmans[3][1]; s != "" {
deflateGlobalsWriteDynamicHuffmanBits(s)
} else {
return nil, fmt.Errorf("no code for distance symbol 2")
}
return stateDeflateDynamicHuffman, nil
} else if line == "endOfBlock" {
s := g.huffmans[2][256]
if s == "" {
return nil, fmt.Errorf("no code for end-of-block (256)")
}
deflateGlobalsWriteDynamicHuffmanBits(s)
return stateDeflateDynamicHuffman, nil
}
return nil, fmt.Errorf("bad stateDeflateDynamicHuffman command: %q", line)
}
func stateDeflateDynamicHuffmanHuffman(line string) (stateFunc, error) {
g := &deflateGlobals
outer:
switch {
case line == "}":
g.whichHuffman = 0
g.prevLine = ""
g.etcetera = false
// If we have all three Huffman tables, write them.
for i := 1; ; i++ {
if i == 4 {
if err := deflateGlobalsWriteDynamicHuffmanTables(); err != nil {
return nil, err
}
break
}
if g.huffmans[i] == nil {
break
}
}
return stateDeflateDynamicHuffman, nil
case line == "etcetera":
g.etcetera = true
return stateDeflateDynamicHuffmanHuffman, nil
default:
s := line
n, s, ok := parseNum(s)
if !ok || s == "" {
break
}
for i := 0; i < len(s); i++ {
if c := s[i]; c != '0' && c != '1' {
break outer
}
}
if (len(s) < 1) || (15 < len(s)) {
return nil, fmt.Errorf("%q code length, %d, is out of range", s, len(s))
}
if g.etcetera {
g.etcetera = false
n0, s0, ok := parseNum(g.prevLine)
if !ok {
return nil, fmt.Errorf("bad etcetera command")
}
if err := stateDeflateDHHEtcetera(n0, s0, n, s); err != nil {
return nil, err
}
}
if g.huffmans[g.whichHuffman] == nil {
g.huffmans[g.whichHuffman] = deflateHuffmanTable{}
}
g.huffmans[g.whichHuffman][n] = s
g.prevLine = line
return stateDeflateDynamicHuffmanHuffman, nil
}
return nil, fmt.Errorf("bad stateDeflateDynamicHuffmanHuffman command: %q", line)
}
// stateDeflateDHHEtcetera expands the "etcetera" line in:
//
// 0 0000
// 1 0001
// etcetera
// 7 0111
//
// to produce the implicit lines:
//
// 0 0000
// 1 0001
// 2 0010
// 3 0011
// 4 0100
// 5 0101
// 6 0110
// 7 0111
func stateDeflateDHHEtcetera(n0 uint32, s0 string, n1 uint32, s1 string) error {
b := []byte(s0)
if !incrementBitstring(b) {
return fmt.Errorf("etcetera: could not increment bitstring")
}
for n := n0 + 1; n < n1; n++ {
line := fmt.Sprintf("%d %s", n, b)
if _, err := stateDeflateDynamicHuffmanHuffman(line); err != nil {
return err
}
if !incrementBitstring(b) {
return fmt.Errorf("etcetera: could not increment bitstring")
}
}
if string(b) != s1 {
return fmt.Errorf("etcetera: final bitstring: got %q, want %q", b, s1)
}
return nil
}
func incrementBitstring(b []byte) (ok bool) {
for i := len(b) - 1; i >= 0; i-- {
switch b[i] {
case '0':
b[i] = '1'
return true
case '1':
b[i] = '0'
default:
return false
}
}
return false
}
type deflateBitStream struct {
bits uint32
nBits uint32 // Always within [0, 7].
}
// writeBits writes the low n bits of b to z.
func (z *deflateBitStream) 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 {
out = append(out, uint8(z.bits))
z.bits >>= 8
z.nBits -= 8
}
}
func (z *deflateBitStream) writeBytes(b []byte) {
z.flush()
out = append(out, b...)
}
func (z *deflateBitStream) writeFixedHuffmanLCode(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 *deflateBitStream) flush() {
if z.nBits > 0 {
out = append(out, uint8(z.bits))
z.bits = 0
z.nBits = 0
}
}
func deflateEncodeLength(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("deflateEncodeLength: l=%d", l))
}
func deflateEncodeDistance(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("deflateEncodeDistance: d=%d", d))
}
func deflateParseLiteral(s string) (lit string, ok bool) {
// TODO: support "\xAB" escape codes in the script?
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 deflateParseLenDist(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 init() {
formats["gif"] = stateGif
}
var gifGlobals struct {
imageWidth uint32
imageHeight uint32
imageBackgroundColorIndex uint32
frameInterlaced bool
frameLeft uint32
frameTop uint32
frameWidth uint32
frameHeight uint32
globalPalette [][4]uint8
localPalette [][4]uint8
}
func stateGif(line string) (stateFunc, error) {
const (
cmdB = "bytes "
cmdGC = "graphicControl "
cmdL = "lzw "
cmdLC = "loopCount "
)
outer:
switch {
case line == "":
return stateGif, nil
case line == "frame {":
gifGlobals.frameInterlaced = false
gifGlobals.frameLeft = 0
gifGlobals.frameTop = 0
gifGlobals.frameWidth = 0
gifGlobals.frameHeight = 0
gifGlobals.localPalette = nil
out = append(out, 0x2C)
return stateGifFrame, nil
case line == "header":
out = append(out, "GIF89a"...)
return stateGif, nil
case line == "image {":
return stateGifImage, nil
case line == "trailer":
out = append(out, 0x3B)
return stateGif, nil
case strings.HasPrefix(line, cmdB):
s := line[len(cmdB):]
for s != "" {
x, ok := uint32(0), false
x, s, ok = parseHex(s)
if !ok {
break outer
}
out = append(out, uint8(x))
}
return stateGif, nil
case strings.HasPrefix(line, cmdGC):
s := line[len(cmdGC):]
flags := uint8(0)
duration := uint32(0)
transparentIndex := uint8(0)
for s != "" {
term := ""
if i := strings.IndexByte(s, ' '); i >= 0 {
term, s = s[:i], s[i+1:]
} else {
term, s = s, ""
}
const (
ms = "ms"
trans = "transparentIndex="
)
switch {
case term == "animationDisposalNone":
flags |= 0x00
case term == "animationDisposalRestoreBackground":
flags |= 0x08
case term == "animationDisposalRestorePrevious":
flags |= 0x0C
case strings.HasPrefix(term, trans):
num, err := strconv.ParseUint(term[len(trans):], 0, 8)
if err != nil {
break outer
}
flags |= 0x01
transparentIndex = uint8(num)
case strings.HasSuffix(term, ms):
num, remaining, ok := parseNum(term[:len(term)-len(ms)])
if !ok || remaining != "" {
break outer
}
duration = num / 10 // GIF's unit of time is 10ms.
default:
break outer
}
}
out = append(out,
0x21, 0xF9, 0x04,
flags,
uint8(duration>>0),
uint8(duration>>8),
transparentIndex,
0x00,
)
return stateGif, nil
case strings.HasPrefix(line, cmdL):
s := line[len(cmdL):]
litWidth, s, ok := parseNum(s)
if !ok || litWidth < 2 || 8 < litWidth {
break
}
out = append(out, uint8(litWidth))
uncompressed := []byte(nil)
for s != "" {
x := uint32(0)
x, s, ok = parseHex(s)
if !ok {
break outer
}
uncompressed = append(uncompressed, uint8(x))
}
buf := bytes.NewBuffer(nil)
w := lzw.NewWriter(buf, lzw.LSB, int(litWidth))
if _, err := w.Write(uncompressed); err != nil {
return nil, err
}
if err := w.Close(); err != nil {
return nil, err
}
compressed := buf.Bytes()
for len(compressed) > 0 {
if len(compressed) <= 0xFF {
out = append(out, uint8(len(compressed)))
out = append(out, compressed...)
compressed = nil
} else {
out = append(out, 0xFF)
out = append(out, compressed[:0xFF]...)
compressed = compressed[0xFF:]
}
}
out = append(out, 0x00)
return stateGif, nil
case strings.HasPrefix(line, cmdLC):
s := line[len(cmdLC):]
loopCount, _, ok := parseNum(s)
if !ok || 0xFFFF < loopCount {
break
}
out = append(out,
0x21, // Extension Introducer.
0xFF, // Application Extension Label.
0x0B, // Block Size.
)
out = append(out, "NETSCAPE2.0"...)
out = append(out,
0x03, // Block Size.
0x01, // Magic Number.
byte(loopCount),
byte(loopCount>>8),
0x00, // Block Terminator.
)
return stateGif, nil
}
return nil, fmt.Errorf("bad stateGif command: %q", line)
}
func stateGifImage(line string) (stateFunc, error) {
g := &gifGlobals
if line == "}" {
out = appendU16LE(out, uint16(g.imageWidth))
out = appendU16LE(out, uint16(g.imageHeight))
if g.globalPalette == nil {
out = append(out, 0x00)
} else if n := log2(uint32(len(g.globalPalette))); n < 2 || 8 < n {
return nil, fmt.Errorf("bad len(g.globalPalette): %d", len(g.globalPalette))
} else {
out = append(out, 0x80|uint8(n-1))
}
out = append(out, uint8(g.imageBackgroundColorIndex))
out = append(out, 0x00)
for _, x := range g.globalPalette {
out = append(out, x[0], x[1], x[2])
}
return stateGif, nil
}
const (
cmdBCI = "backgroundColorIndex "
cmdIWH = "imageWidthHeight "
cmdP = "palette {"
)
switch {
case strings.HasPrefix(line, cmdBCI):
s := line[len(cmdBCI):]
if i, _, ok := parseNum(s); ok {
g.imageBackgroundColorIndex = i
}
return stateGifImage, nil
case strings.HasPrefix(line, cmdIWH):
s := line[len(cmdIWH):]
if w, s, ok := parseNum(s); ok {
if h, _, ok := parseNum(s); ok {
g.imageWidth = w
g.imageHeight = h
return stateGifImage, nil
}
}
case strings.HasPrefix(line, cmdP):
return stateGifImagePalette, nil
}
return nil, fmt.Errorf("bad stateGifImage command: %q", line)
}
func stateGifFrame(line string) (stateFunc, error) {
g := &gifGlobals
if line == "}" {
out = appendU16LE(out, uint16(g.frameLeft))
out = appendU16LE(out, uint16(g.frameTop))
out = appendU16LE(out, uint16(g.frameWidth))
out = appendU16LE(out, uint16(g.frameHeight))
flags := byte(0x00)
if g.frameInterlaced {
flags |= 0x40
}
if g.localPalette == nil {
out = append(out, flags)
} else if n := log2(uint32(len(g.localPalette))); n < 2 || 8 < n {
return nil, fmt.Errorf("bad len(g.localPalette): %d", len(g.localPalette))
} else {
out = append(out, flags|0x80|uint8(n-1))
}
for _, x := range g.localPalette {
out = append(out, x[0], x[1], x[2])
}
return stateGif, nil
}
const (
cmdFLTWH = "frameLeftTopWidthHeight "
cmdP = "palette {"
)
switch {
case line == "interlaced":
g.frameInterlaced = true
return stateGifFrame, nil
case strings.HasPrefix(line, cmdFLTWH):
s := line[len(cmdFLTWH):]
if l, s, ok := parseNum(s); ok {
if t, s, ok := parseNum(s); ok {
if w, s, ok := parseNum(s); ok {
if h, _, ok := parseNum(s); ok {
g.frameLeft = l
g.frameTop = t
g.frameWidth = w
g.frameHeight = h
return stateGifFrame, nil
}
}
}
}
case strings.HasPrefix(line, cmdP):
return stateGifFramePalette, nil
}
return nil, fmt.Errorf("bad stateGifFrame command: %q", line)
}
func stateGifImagePalette(line string) (stateFunc, error) {
g := &gifGlobals
if line == "}" {
return stateGifImage, nil
}
s := line
if rgb0, s, ok := parseHex(s); ok {
if rgb1, s, ok := parseHex(s); ok {
if rgb2, _, ok := parseHex(s); ok {
g.globalPalette = append(g.globalPalette,
[4]uint8{uint8(rgb0), uint8(rgb1), uint8(rgb2), 0xFF})
return stateGifImagePalette, nil
}
}
}
return nil, fmt.Errorf("bad stateGifImagePalette command: %q", line)
}
func stateGifFramePalette(line string) (stateFunc, error) {
g := &gifGlobals
if line == "}" {
return stateGifFrame, nil
}
s := line
if rgb0, s, ok := parseHex(s); ok {
if rgb1, s, ok := parseHex(s); ok {
if rgb2, _, ok := parseHex(s); ok {
g.localPalette = append(g.localPalette,
[4]uint8{uint8(rgb0), uint8(rgb1), uint8(rgb2), 0xFF})
return stateGifFramePalette, nil
}
}
}
return nil, fmt.Errorf("bad stateGifFramePalette command: %q", line)
}