| // Copyright 2018 The Wuffs Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // https://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| //go:build ignore |
| // +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" |
| "compress/zlib" |
| "fmt" |
| "hash/crc32" |
| "io" |
| "os" |
| "sort" |
| "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 := io.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 := parseNum32(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 appendU32BE(b []byte, u uint32) []byte { |
| return append(b, uint8(u>>24), uint8(u>>16), uint8(u>>8), uint8(u)) |
| } |
| |
| 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 parseHex32(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 parseHex64(s string) (num uint64, 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, 64) |
| if err != nil { |
| return 0, "", false |
| } |
| return u, remaining, true |
| } |
| |
| func parseNum32(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["bzip2"] = stateBzip2 |
| } |
| |
| var bzip2Globals struct { |
| stream bzip2BitStream |
| } |
| |
| func stateBzip2(line string) (stateFunc, error) { |
| g := &bzip2Globals |
| const ( |
| cmdB = "bits " |
| ) |
| switch { |
| case line == "": |
| g.stream.flush() |
| return stateBzip2, nil |
| |
| case strings.HasPrefix(line, cmdB): |
| s := strings.TrimSpace(line[len(cmdB):]) |
| n, s, ok := parseNum32(s) |
| if !ok || s == "" { |
| break |
| } |
| x, s, ok := parseHex64(s) |
| if !ok { |
| break |
| } |
| g.stream.writeBits64(x, n) |
| return stateBzip2, nil |
| } |
| |
| return nil, fmt.Errorf("bad stateBzip2 command: %q", line) |
| } |
| |
| type bzip2BitStream struct { |
| bits uint64 |
| nBits uint32 // Always within [0, 7]. |
| } |
| |
| // writeBits64 writes the low n bits of b to z. |
| func (z *bzip2BitStream) writeBits64(b uint64, n uint32) { |
| if n > 56 { |
| panic("writeBits64: n is too large") |
| } |
| z.bits |= b << (64 - n - z.nBits) |
| z.nBits += n |
| for z.nBits >= 8 { |
| out = append(out, uint8(z.bits>>56)) |
| z.bits <<= 8 |
| z.nBits -= 8 |
| } |
| } |
| |
| func (z *bzip2BitStream) flush() { |
| if z.nBits > 0 { |
| out = append(out, uint8(z.bits>>56)) |
| z.bits = 0 |
| z.nBits = 0 |
| } |
| } |
| |
| // ---- |
| |
| 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, |
| } |
| |
| var deflateHuffmanNames = [4]string{ |
| 0: "Unused", |
| 1: "CodeLength", |
| 2: "Literal/Length", |
| 3: "Distance", |
| } |
| |
| type deflateHuffmanTable map[uint32]string |
| |
| var deflateGlobals struct { |
| bncData []byte |
| stream deflateBitStream |
| |
| // Dynamic Huffman state. whichHuffman indexes the huffmans array. See also |
| // deflateHuffmanNames. |
| whichHuffman uint32 |
| huffmans [4]deflateHuffmanTable |
| |
| // DHH (Dynamic Huffman, inside a Huffman table) state. |
| prevLine string |
| etcetera bool |
| incomplete bool |
| } |
| |
| func deflateGlobalsClearDynamicHuffmanState() { |
| deflateGlobals.whichHuffman = 0 |
| deflateGlobals.huffmans = [4]deflateHuffmanTable{} |
| deflateGlobals.prevLine = "" |
| deflateGlobals.etcetera = false |
| deflateGlobals.incomplete = 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 deflateGlobalsIsHuffmanCanonical() bool { |
| g := &deflateGlobals |
| |
| // Gather the code+bitstring pairs. Deflate bitstrings cannot be longer |
| // than 15 bits. |
| type pair struct { |
| k uint32 |
| v string |
| } |
| pairs := []pair{} |
| for k, v := range g.huffmans[g.whichHuffman] { |
| if len(v) > 15 { |
| return false |
| } |
| pairs = append(pairs, pair{k, v}) |
| } |
| if len(pairs) == 0 { |
| return false |
| } |
| |
| // Sort by bitstring-length and then code. |
| sort.Slice(pairs, func(i, j int) bool { |
| pi, pj := &pairs[i], &pairs[j] |
| if len(pi.v) != len(pj.v) { |
| return len(pi.v) < len(pj.v) |
| } |
| return pi.k < pj.k |
| }) |
| |
| // Set up a generator for the canonical bitstrings. |
| buf := [15]byte{'0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0'} |
| prevV := "" |
| next := func() bool { |
| if i := len(prevV); i > 0 { |
| for { |
| i-- |
| if i < 0 { |
| return false |
| } |
| if buf[i] == '0' { |
| buf[i] = '1' |
| break |
| } |
| buf[i] = '0' |
| } |
| } |
| return true |
| } |
| |
| // Verify the bitstrings. |
| for _, p := range pairs { |
| if !next() { |
| return false // Over-subscribed. |
| } else if p.v != string(buf[:len(p.v)]) { |
| return false // Non-canonical. |
| } |
| prevV = p.v |
| } |
| if next() != g.incomplete { |
| return false // Under-subscribed. |
| } |
| return true |
| } |
| |
| 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 = parseHex32(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 > 10) || (d > 4) { |
| return nil, fmt.Errorf("TODO: support len/dist ExtraBits > 0 for dynamic Huffman blocks") |
| } |
| // len 3 is code 257, len 4 is code 258, etc. All with no ExtraBits. |
| if s := g.huffmans[2][l+254]; s != "" { |
| deflateGlobalsWriteDynamicHuffmanBits(s) |
| } else { |
| return nil, fmt.Errorf("no code for literal/length symbol %d", l+254) |
| } |
| // dist 1 is code 0, dist 2 is code 1, etc. All with no ExtraBits. |
| if s := g.huffmans[3][d-1]; s != "" { |
| deflateGlobalsWriteDynamicHuffmanBits(s) |
| } else { |
| return nil, fmt.Errorf("no code for distance symbol %d", d-1) |
| } |
| 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 == "}": |
| if !deflateGlobalsIsHuffmanCanonical() { |
| return nil, fmt.Errorf(`"huffman %s" is non-canonical`, deflateHuffmanNames[g.whichHuffman]) |
| } |
| g.whichHuffman = 0 |
| g.prevLine = "" |
| g.etcetera = false |
| g.incomplete = 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 |
| |
| case line == "incomplete": |
| g.incomplete = true |
| return stateDeflateDynamicHuffmanHuffman, nil |
| |
| default: |
| s := line |
| n, s, ok := parseNum32(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 := parseNum32(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 := parseNum32(s); ok && 3 <= l && l <= 258 { |
| if strings.HasPrefix(s, dStr) { |
| s = s[len(dStr):] |
| if d, s, ok := parseNum32(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 = parseHex32(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 := parseNum32(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 := parseNum32(s) |
| if !ok || litWidth < 2 || 8 < litWidth { |
| break |
| } |
| out = append(out, uint8(litWidth)) |
| |
| uncompressed := []byte(nil) |
| for s != "" { |
| x := uint32(0) |
| x, s, ok = parseHex32(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 := parseNum32(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 := parseNum32(s); ok { |
| g.imageBackgroundColorIndex = i |
| } |
| return stateGifImage, nil |
| |
| case strings.HasPrefix(line, cmdIWH): |
| s := line[len(cmdIWH):] |
| if w, s, ok := parseNum32(s); ok { |
| if h, _, ok := parseNum32(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 := parseNum32(s); ok { |
| if t, s, ok := parseNum32(s); ok { |
| if w, s, ok := parseNum32(s); ok { |
| if h, _, ok := parseNum32(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 := parseHex32(s); ok { |
| if rgb1, s, ok := parseHex32(s); ok { |
| if rgb2, _, ok := parseHex32(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 := parseHex32(s); ok { |
| if rgb1, s, ok := parseHex32(s); ok { |
| if rgb2, _, ok := parseHex32(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) |
| } |
| |
| // ---- |
| |
| func init() { |
| formats["png"] = statePng |
| } |
| |
| var pngGlobals struct { |
| scratch [4]byte |
| |
| animSeqNum uint32 |
| chunkData bytes.Buffer |
| chunkType string |
| zlibWriter *zlib.Writer |
| } |
| |
| func statePng(line string) (stateFunc, error) { |
| g := &pngGlobals |
| switch { |
| case line == "": |
| return statePng, nil |
| |
| case line == "magic": |
| out = append(out, "\x89PNG\x0D\x0A\x1A\x0A"...) |
| return statePng, nil |
| |
| case (len(line) == 6) && (line[4] == ' ') && (line[5] == '{'): |
| g.chunkData.Reset() |
| g.chunkType = line[:4] |
| return statePngChunk, nil |
| } |
| |
| return nil, fmt.Errorf("bad statePng command: %q", line) |
| } |
| |
| func statePngChunk(line string) (stateFunc, error) { |
| g := &pngGlobals |
| if line == "}" { |
| if n := g.chunkData.Len(); n > 0xFFFF_FFFF { |
| return nil, fmt.Errorf("chunkData is too long") |
| } |
| out = appendU32BE(out, uint32(g.chunkData.Len())) |
| n := len(out) |
| out = append(out, g.chunkType...) |
| out = append(out, g.chunkData.Bytes()...) |
| out = appendU32BE(out, crc32.ChecksumIEEE(out[n:])) |
| return statePng, nil |
| } |
| |
| switch { |
| case line == "animSeqNum++": |
| g.chunkData.Write(appendU32BE(g.scratch[:0], g.animSeqNum)) |
| g.animSeqNum++ |
| return statePngChunk, nil |
| |
| case line == "raw {": |
| return statePngRaw, nil |
| |
| case line == "zlib {": |
| g.zlibWriter = zlib.NewWriter(&g.chunkData) |
| return statePngZlib, nil |
| } |
| |
| return nil, fmt.Errorf("bad statePngChunk command: %q", line) |
| } |
| |
| func statePngRaw(line string) (stateFunc, error) { |
| g := &pngGlobals |
| if line == "}" { |
| return statePngChunk, nil |
| } |
| |
| for s := line; s != ""; { |
| if x, remaining, ok := parseHex32(s); ok { |
| g.chunkData.WriteByte(byte(x)) |
| s = remaining |
| } else { |
| return nil, fmt.Errorf("bad statePngRaw command: %q", line) |
| } |
| } |
| return statePngRaw, nil |
| } |
| |
| func statePngZlib(line string) (stateFunc, error) { |
| g := &pngGlobals |
| if line == "}" { |
| if err := g.zlibWriter.Close(); err != nil { |
| return nil, fmt.Errorf("statePngZlib: %w", err) |
| } |
| return statePngChunk, nil |
| } |
| |
| for s := line; s != ""; { |
| if x, remaining, ok := parseHex32(s); ok { |
| g.scratch[0] = byte(x) |
| g.zlibWriter.Write(g.scratch[:1]) |
| s = remaining |
| } else { |
| return nil, fmt.Errorf("bad statePngZlib command: %q", line) |
| } |
| } |
| return statePngZlib, nil |
| } |