File: bitdump.go 1 /* 2 The MIT License (MIT) 3 4 Copyright (c) 2026 pacman64 5 6 Permission is hereby granted, free of charge, to any person obtaining a copy of 7 this software and associated documentation files (the "Software"), to deal 8 in the Software without restriction, including without limitation the rights to 9 use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies 10 of the Software, and to permit persons to whom the Software is furnished to do 11 so, subject to the following conditions: 12 13 The above copyright notice and this permission notice shall be included in all 14 copies or substantial portions of the Software. 15 16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 19 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 22 SOFTWARE. 23 */ 24 25 /* 26 To compile a smaller-sized command-line app, you can use the `go` command as 27 follows: 28 29 go build -ldflags "-s -w" -trimpath bitdump.go 30 */ 31 32 package main 33 34 import ( 35 "bufio" 36 "errors" 37 "io" 38 "os" 39 "strconv" 40 ) 41 42 const info = ` 43 bitdump [options...] [filenames...] 44 45 46 Show all bits for all input bytes, starting each output line with the 47 leading byte's offset. 48 49 All (optional) leading options start with either single or double-dash: 50 51 -h, -help show this help message 52 -no-offset, -no-offsets don't start lines with current byte offsets 53 -tab, -tabs separate items with tabs instead of spaces 54 ` 55 56 const itemsPerLine = 8 57 58 func main() { 59 emitOffsets := true 60 separator := byte(' ') 61 args := os.Args[1:] 62 63 for len(args) > 0 { 64 switch args[0] { 65 case `-h`, `--h`, `-help`, `--help`: 66 os.Stdout.WriteString(info[1:]) 67 return 68 69 case `-no-offset`, `--no-offset`, `-no-offsets`, `--no-offsets`: 70 emitOffsets = false 71 args = args[1:] 72 continue 73 74 case `-tab`, `--tab`, `-tabs`, `--tabs`: 75 separator = '\t' 76 args = args[1:] 77 continue 78 } 79 80 break 81 } 82 83 if len(args) > 0 && args[0] == `--` { 84 args = args[1:] 85 } 86 87 var p params 88 p.emitOffset = emitNoOffset 89 if emitOffsets { 90 p.emitOffset = emitDecimalOffset 91 } 92 p.separator = separator 93 94 if err := run(os.Stdout, p, args); err != nil && err != io.EOF { 95 os.Stderr.WriteString(err.Error()) 96 os.Stderr.WriteString("\n") 97 os.Exit(1) 98 } 99 } 100 101 type params struct { 102 offset *int64 103 emitOffset func(w *bufio.Writer, offset int64, sep byte) 104 separator byte 105 } 106 107 func run(w io.Writer, p params, args []string) error { 108 offset := int64(0) 109 p.offset = &offset 110 bw := bufio.NewWriter(w) 111 defer func() { 112 if offset%itemsPerLine == 0 && offset > 0 { 113 bw.WriteByte('\n') 114 } 115 bw.Flush() 116 }() 117 118 if len(args) == 0 { 119 return bitdump(bw, os.Stdin, p) 120 } 121 122 for _, name := range args { 123 if err := handleFile(bw, name, p); err != nil { 124 return err 125 } 126 } 127 return nil 128 } 129 130 func handleFile(w *bufio.Writer, name string, p params) error { 131 if name == `` || name == `-` { 132 return bitdump(w, os.Stdin, p) 133 } 134 135 f, err := os.Open(name) 136 if err != nil { 137 return errors.New(`can't read from file named "` + name + `"`) 138 } 139 defer f.Close() 140 141 return bitdump(w, f, p) 142 } 143 144 func bitdump(w *bufio.Writer, r io.Reader, p params) error { 145 var buf [32 * 1024]byte 146 defer w.Flush() 147 148 for { 149 n, err := r.Read(buf[:]) 150 if n < 1 && err == io.EOF { 151 return nil 152 } 153 154 if err != nil && err != io.EOF { 155 return err 156 } 157 158 chunk := buf[:n] 159 160 for len(chunk) >= itemsPerLine { 161 if err := emitChunk(w, chunk[:itemsPerLine], p); err != nil { 162 return err 163 } 164 165 chunk = chunk[itemsPerLine:] 166 *p.offset += itemsPerLine 167 } 168 169 if len(chunk) > 0 { 170 if err := emitChunk(w, chunk, p); err != nil { 171 return err 172 } 173 174 *p.offset += int64(len(chunk)) 175 } 176 } 177 } 178 179 func emitDecimalOffset(w *bufio.Writer, offset int64, sep byte) { 180 const pad = `00000000` 181 var str [24]byte 182 183 s := strconv.AppendInt(str[:0], offset, 10) 184 // pad small offsets with leading zeros 185 if len(s) < len(pad) { 186 w.WriteString(pad[len(s):]) 187 } 188 w.Write(s) 189 w.WriteByte(sep) 190 } 191 192 func emitNoOffset(w *bufio.Writer, offset int64, sep byte) { 193 // deliberately does nothing 194 } 195 196 func emitChunk(w *bufio.Writer, chunk []byte, p params) error { 197 p.emitOffset(w, *p.offset, p.separator) 198 for i, b := range chunk { 199 if i > 0 { 200 w.WriteByte(p.separator) 201 } 202 w.WriteString(bits[b]) 203 } 204 205 if err := w.WriteByte('\n'); err != nil { 206 // assume a write error is the consequence of stdout 207 // being closed, perhaps by another app along a pipe 208 return io.EOF 209 } 210 return nil 211 } 212 213 /* 214 tlp = '(f"{bin(v)[2:]:>08}" for v in range(256))' | lineup 6 | 215 gsub '\t' '`, `' | tlp 'f"\t`{l}`,"' 216 */ 217 var bits = [256]string{ 218 `00000000`, `00000001`, `00000010`, `00000011`, `00000100`, `00000101`, 219 `00000110`, `00000111`, `00001000`, `00001001`, `00001010`, `00001011`, 220 `00001100`, `00001101`, `00001110`, `00001111`, `00010000`, `00010001`, 221 `00010010`, `00010011`, `00010100`, `00010101`, `00010110`, `00010111`, 222 `00011000`, `00011001`, `00011010`, `00011011`, `00011100`, `00011101`, 223 `00011110`, `00011111`, `00100000`, `00100001`, `00100010`, `00100011`, 224 `00100100`, `00100101`, `00100110`, `00100111`, `00101000`, `00101001`, 225 `00101010`, `00101011`, `00101100`, `00101101`, `00101110`, `00101111`, 226 `00110000`, `00110001`, `00110010`, `00110011`, `00110100`, `00110101`, 227 `00110110`, `00110111`, `00111000`, `00111001`, `00111010`, `00111011`, 228 `00111100`, `00111101`, `00111110`, `00111111`, `01000000`, `01000001`, 229 `01000010`, `01000011`, `01000100`, `01000101`, `01000110`, `01000111`, 230 `01001000`, `01001001`, `01001010`, `01001011`, `01001100`, `01001101`, 231 `01001110`, `01001111`, `01010000`, `01010001`, `01010010`, `01010011`, 232 `01010100`, `01010101`, `01010110`, `01010111`, `01011000`, `01011001`, 233 `01011010`, `01011011`, `01011100`, `01011101`, `01011110`, `01011111`, 234 `01100000`, `01100001`, `01100010`, `01100011`, `01100100`, `01100101`, 235 `01100110`, `01100111`, `01101000`, `01101001`, `01101010`, `01101011`, 236 `01101100`, `01101101`, `01101110`, `01101111`, `01110000`, `01110001`, 237 `01110010`, `01110011`, `01110100`, `01110101`, `01110110`, `01110111`, 238 `01111000`, `01111001`, `01111010`, `01111011`, `01111100`, `01111101`, 239 `01111110`, `01111111`, `10000000`, `10000001`, `10000010`, `10000011`, 240 `10000100`, `10000101`, `10000110`, `10000111`, `10001000`, `10001001`, 241 `10001010`, `10001011`, `10001100`, `10001101`, `10001110`, `10001111`, 242 `10010000`, `10010001`, `10010010`, `10010011`, `10010100`, `10010101`, 243 `10010110`, `10010111`, `10011000`, `10011001`, `10011010`, `10011011`, 244 `10011100`, `10011101`, `10011110`, `10011111`, `10100000`, `10100001`, 245 `10100010`, `10100011`, `10100100`, `10100101`, `10100110`, `10100111`, 246 `10101000`, `10101001`, `10101010`, `10101011`, `10101100`, `10101101`, 247 `10101110`, `10101111`, `10110000`, `10110001`, `10110010`, `10110011`, 248 `10110100`, `10110101`, `10110110`, `10110111`, `10111000`, `10111001`, 249 `10111010`, `10111011`, `10111100`, `10111101`, `10111110`, `10111111`, 250 `11000000`, `11000001`, `11000010`, `11000011`, `11000100`, `11000101`, 251 `11000110`, `11000111`, `11001000`, `11001001`, `11001010`, `11001011`, 252 `11001100`, `11001101`, `11001110`, `11001111`, `11010000`, `11010001`, 253 `11010010`, `11010011`, `11010100`, `11010101`, `11010110`, `11010111`, 254 `11011000`, `11011001`, `11011010`, `11011011`, `11011100`, `11011101`, 255 `11011110`, `11011111`, `11100000`, `11100001`, `11100010`, `11100011`, 256 `11100100`, `11100101`, `11100110`, `11100111`, `11101000`, `11101001`, 257 `11101010`, `11101011`, `11101100`, `11101101`, `11101110`, `11101111`, 258 `11110000`, `11110001`, `11110010`, `11110011`, `11110100`, `11110101`, 259 `11110110`, `11110111`, `11111000`, `11111001`, `11111010`, `11111011`, 260 `11111100`, `11111101`, `11111110`, `11111111`, 261 }