Simple program to encode ASCII punch card files for the IBM 1401 into binary (BCD) the machine understands.

ibm1401-bc.js

/**
 * This is a simple program to encode ASCII punch card files for the IBM 1401
 * into binary the machine understands.
 *
 * The IBM 1401 was build before ASCII was invented, so it used its own binary
 * encoding for characters. This program will encode all ASCII into
 * corresponding 1401 encoding.
 *
 * Usage: node ibm1401-bc.js <file>
 *
 * The file should be a plain ASCII file containing the punch card code, e.g.:
 *
 * ,0080015,022029,M077211
 *
 * -----------------------------------------------------------------------------
 *
 * Copyright (c) 2020 Martin Albrecht <martin.albrecht@seriousmonkey.de>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
const fs = require('fs')

// BCD character encodings
// Bit positions are: WM | C | B | A | 8 | 4 | 2 | 1
const CharacterEncodings = {
    // Default SimH encoding
    default: {
        'A': 0b00110001, 'B': 0b00110010, 'C': 0b01110011, 'D': 0b00110100,
        'E': 0b01110101, 'F': 0b01110110, 'G': 0b00110111, 'H': 0b00111000,
        'I': 0b01111001, '&': 0b01110000, '.': 0b00111011, ')': 0b01111100,
        'J': 0b01100001, 'K': 0b01100010, 'L': 0b00100011, 'M': 0b01100100,
        'N': 0b00100101, 'O': 0b00100110, 'P': 0b01100111, 'Q': 0b01101000,
        'R': 0b00101001, '-': 0b00100000, '$': 0b01101011, '*': 0b00101100,
        '/': 0b01010001, 'S': 0b01010010, 'T': 0b00010011, 'U': 0b01010100,
        'V': 0b00010101, 'W': 0b00010110, 'X': 0b01010111, 'Y': 0b01011000,
        'Z': 0b00011001, '\'': 0b00011010, ',': 0b01011011, '%': 0b00011100,
        '#': 0b00001011, '@': 0b01001100, '0': 0b01001010, '1': 0b00000001,
        '2': 0b00000010, '3': 0b01000011, '4': 0b00000100, '5': 0b01000101,
        '6': 0b01000110, '7': 0b00000111, '8': 0b00001000, '9': 0b01001001,
        ' ': 0b01000000, ':': 0b00001101, '>': 0b00001110, '(': 0b01001111,
        '^': 0b00010000, '\\': 0b01011110, '+': 0b00011111, '!': 0b00101010,
        ']': 0b01101101, ';': 0b01101110, '_': 0b00101111, '?': 0b01111010,
        '[': 0b00111101, '<': 0b00111110, '"': 0b01111111
    },
}

var assembly = (buffer, encoding, filename) => {
    if (buffer && encoding && filename) {
        let binaryData = Buffer.alloc(buffer.length)

        // Iterate over characters
        for (let c = 0, len = buffer.length; c < len; c++) {
            if (buffer[c] && buffer[c] !== '\n') {
                if (CharacterEncodings[encoding].hasOwnProperty(buffer[c])) {
                    binaryData[c] = CharacterEncodings[encoding][buffer[c]]
                } else {
                    const err = `Aborting on unknown character: ` +
                        `${buffer[c]} at index ${c}\n` +
                        `Dec: ${c.toString(10)}` +
                        ` | Hex: ${c.toString(16)}` +
                        ` | Bin: ${c.toString(2)}\n`
                    throw new Error(err)
                }
            }
        }

        console.log(`\nWRITING FILE:\t${filename}.bc\nLENGTH:\t\t${binaryData.length} bytes`)
        fs.writeFileSync(`${filename}.bc`, binaryData, 'binary')
    }
}

var disassembly = (buffer, encoding, filename) => {
    let asciiData = ''

    if (buffer && encoding && filename) {
        for (let c = 0, len = buffer.length; c < len; c++) {
            if (buffer[c] && buffer[c] !== '\n') {
                for (let item in CharacterEncodings[encoding]) {
                    if (CharacterEncodings[encoding].hasOwnProperty(item)) {
                        if (CharacterEncodings[encoding][item] == buffer[c]) {
                            asciiData += item
                            break
                        }
                    }
                }
            }
        }
    }

    console.log(`\nWRITING FILE:\t${filename}.dis\nLENGTH:\t\t${asciiData.length} bytes`)
    fs.writeFileSync(`${filename}.dis`, asciiData)
}

var usage = () => {
    throw (`Usage: .${__filename} [-d] -f <file>`)
}

try {
    // Parse command line arguments
    const argv = process.argv
    if (argv.length < 3) {
        usage()
    }

    // Fetch file name and extension
    let index = argv.indexOf('-f')
    if (index === -1) {
        usage()
    }

    const filename = argv[index + 1].trim().split('.')
    const extension = filename.splice(-1)
    if (!filename || !extension) {
        throw (`Error: Invalid filename. Should be of scheme: FILENAME.EXT, but is: ${argv[index + 1]}`)
    }

    const disassemble = argv.indexOf('-d') !== -1

    // Set encoding for BCD to ASCII conversion
    const encoding = 'default'

    // Intro banner
    //console.clear()
    console.log('=========== IBM 1401 BINARY ENCODER ===========\n')
    console.log(`READING FILE:\t${filename}\nEXTENSION:\t.${extension}`)
    console.log(`ENCODING:\t${encoding}`)
    console.log(`MODE:\t\t${disassemble ? 'Disassemble' : 'Assemble'}`)

    // Read in data
    const buffer = fs.readFileSync(argv[index + 1])
    if (buffer) {
        if (disassemble) {
            disassembly(buffer, encoding, filename)
        } else {
            assembly(String(buffer).trim().toUpperCase(), encoding, filename)
        }
    }

    console.log('DONE\n')
} catch (e) {
    console.error(e)
}