Brainfuck code generator from bytestrings.

bfgen.py

# (c) Copyright 2020 tripulse.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

import sys
import argparse
import shutil

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description=
        "Regular string to executable Brainfuck code transformer. "
        "This can be thought of as an encoder, and the way to decode "
        "is to execute with a Brainfuck interpreter")

    parser.add_argument('FILE',
        type=argparse.FileType('rb'),
        nargs='?',
        default=sys.stdin.buffer,
        help="Source to read a byte-string from, if unspecified a file"
             "reads from standard-input.")

    parser.add_argument('--low-memory',
        action='store_true',
        help="Generate the code to consume only a single byte in memory "
             "at the cost of more operations, thus more CPU load")

    parser.add_argument('--expansion-factor', 
        type=int,
        default=0,
        help="Expand the output code size by a product of two and a factor. "
             "This is not useful in anyways, just a possblity (for fun?)")

    args = parser.parse_args()


    with args.FILE as inp:
        memops = '-+' if args.expansion_factor else '+'
        after_store = '.[-]' if args.low_memory else '.>'

        while True:
            if not (buf := inp.read(shutil.COPY_BUFSIZE)):
                break
            
            sys.stdout.write(
                after_store.join(memops * c for c in buf) + '.')