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 return 99 } 100 } 101 102 type params struct { 103 offset *int64 104 emitOffset func(w *bufio.Writer, offset int64, sep byte) 105 separator byte 106 } 107 108 func run(w io.Writer, p params, args []string) error { 109 offset := int64(0) 110 p.offset = &offset 111 bw := bufio.NewWriter(w) 112 defer func() { 113 if offset%itemsPerLine == 0 && offset > 0 { 114 bw.WriteByte('\n') 115 } 116 bw.Flush() 117 }() 118 119 if len(args) == 0 { 120 return bitdump(bw, os.Stdin, p) 121 } 122 123 for _, name := range args { 124 if err := handleFile(bw, name, p); err != nil { 125 return err 126 } 127 } 128 return nil 129 } 130 131 func handleFile(w *bufio.Writer, name string, p params) error { 132 if name == `` || name == `-` { 133 return bitdump(w, os.Stdin, p) 134 } 135 136 f, err := os.Open(name) 137 if err != nil { 138 return errors.New(`can't read from file named "` + name + `"`) 139 } 140 defer f.Close() 141 142 return bitdump(w, f, p) 143 } 144 145 func bitdump(w *bufio.Writer, r io.Reader, p params) error { 146 var buf [32 * 1024]byte 147 defer w.Flush() 148 149 for { 150 n, err := r.Read(buf[:]) 151 if n < 1 && err == io.EOF { 152 return nil 153 } 154 155 if err != nil && err != io.EOF { 156 return err 157 } 158 159 chunk := buf[:n] 160 161 for len(chunk) >= itemsPerLine { 162 if err := emitChunk(w, chunk[:itemsPerLine], p); err != nil { 163 return err 164 } 165 166 chunk = chunk[itemsPerLine:] 167 *p.offset += itemsPerLine 168 } 169 170 if len(chunk) > 0 { 171 if err := emitChunk(w, chunk, p); err != nil { 172 return err 173 } 174 175 *p.offset += int64(len(chunk)) 176 } 177 } 178 } 179 180 func emitDecimalOffset(w *bufio.Writer, offset int64, sep byte) { 181 const pad = `00000000` 182 var str [24]byte 183 184 s := strconv.AppendInt(str[:0], offset, 10) 185 // pad small offsets with leading zeros 186 if len(s) < len(pad) { 187 w.WriteString(pad[len(s):]) 188 } 189 w.Write(s) 190 w.WriteByte(sep) 191 } 192 193 func emitNoOffset(w *bufio.Writer, offset int64, sep byte) { 194 // deliberately does nothing 195 } 196 197 func emitChunk(w *bufio.Writer, chunk []byte, p params) error { 198 p.emitOffset(w, *p.offset, p.separator) 199 for i, b := range chunk { 200 if i > 0 { 201 w.WriteByte(p.separator) 202 } 203 w.WriteString(bits[b]) 204 } 205 206 if err := w.WriteByte('\n'); err != nil { 207 // assume a write error is the consequence of stdout 208 // being closed, perhaps by another app along a pipe 209 return io.EOF 210 } 211 return nil 212 } 213 214 /* 215 tlp = '(f"{bin(v)[2:]:>08}" for v in range(256))' | lineup 6 | 216 gsub '\t' '`, `' | tlp 'f"\t`{l}`,"' 217 */ 218 var bits = [256]string{ 219 `00000000`, `00000001`, `00000010`, `00000011`, `00000100`, `00000101`, 220 `00000110`, `00000111`, `00001000`, `00001001`, `00001010`, `00001011`, 221 `00001100`, `00001101`, `00001110`, `00001111`, `00010000`, `00010001`, 222 `00010010`, `00010011`, `00010100`, `00010101`, `00010110`, `00010111`, 223 `00011000`, `00011001`, `00011010`, `00011011`, `00011100`, `00011101`, 224 `00011110`, `00011111`, `00100000`, `00100001`, `00100010`, `00100011`, 225 `00100100`, `00100101`, `00100110`, `00100111`, `00101000`, `00101001`, 226 `00101010`, `00101011`, `00101100`, `00101101`, `00101110`, `00101111`, 227 `00110000`, `00110001`, `00110010`, `00110011`, `00110100`, `00110101`, 228 `00110110`, `00110111`, `00111000`, `00111001`, `00111010`, `00111011`, 229 `00111100`, `00111101`, `00111110`, `00111111`, `01000000`, `01000001`, 230 `01000010`, `01000011`, `01000100`, `01000101`, `01000110`, `01000111`, 231 `01001000`, `01001001`, `01001010`, `01001011`, `01001100`, `01001101`, 232 `01001110`, `01001111`, `01010000`, `01010001`, `01010010`, `01010011`, 233 `01010100`, `01010101`, `01010110`, `01010111`, `01011000`, `01011001`, 234 `01011010`, `01011011`, `01011100`, `01011101`, `01011110`, `01011111`, 235 `01100000`, `01100001`, `01100010`, `01100011`, `01100100`, `01100101`, 236 `01100110`, `01100111`, `01101000`, `01101001`, `01101010`, `01101011`, 237 `01101100`, `01101101`, `01101110`, `01101111`, `01110000`, `01110001`, 238 `01110010`, `01110011`, `01110100`, `01110101`, `01110110`, `01110111`, 239 `01111000`, `01111001`, `01111010`, `01111011`, `01111100`, `01111101`, 240 `01111110`, `01111111`, `10000000`, `10000001`, `10000010`, `10000011`, 241 `10000100`, `10000101`, `10000110`, `10000111`, `10001000`, `10001001`, 242 `10001010`, `10001011`, `10001100`, `10001101`, `10001110`, `10001111`, 243 `10010000`, `10010001`, `10010010`, `10010011`, `10010100`, `10010101`, 244 `10010110`, `10010111`, `10011000`, `10011001`, `10011010`, `10011011`, 245 `10011100`, `10011101`, `10011110`, `10011111`, `10100000`, `10100001`, 246 `10100010`, `10100011`, `10100100`, `10100101`, `10100110`, `10100111`, 247 `10101000`, `10101001`, `10101010`, `10101011`, `10101100`, `10101101`, 248 `10101110`, `10101111`, `10110000`, `10110001`, `10110010`, `10110011`, 249 `10110100`, `10110101`, `10110110`, `10110111`, `10111000`, `10111001`, 250 `10111010`, `10111011`, `10111100`, `10111101`, `10111110`, `10111111`, 251 `11000000`, `11000001`, `11000010`, `11000011`, `11000100`, `11000101`, 252 `11000110`, `11000111`, `11001000`, `11001001`, `11001010`, `11001011`, 253 `11001100`, `11001101`, `11001110`, `11001111`, `11010000`, `11010001`, 254 `11010010`, `11010011`, `11010100`, `11010101`, `11010110`, `11010111`, 255 `11011000`, `11011001`, `11011010`, `11011011`, `11011100`, `11011101`, 256 `11011110`, `11011111`, `11100000`, `11100001`, `11100010`, `11100011`, 257 `11100100`, `11100101`, `11100110`, `11100111`, `11101000`, `11101001`, 258 `11101010`, `11101011`, `11101100`, `11101101`, `11101110`, `11101111`, 259 `11110000`, `11110001`, `11110010`, `11110011`, `11110100`, `11110101`, 260 `11110110`, `11110111`, `11111000`, `11111001`, `11111010`, `11111011`, 261 `11111100`, `11111101`, `11111110`, `11111111`, 262 }