scripts/dbgle32.py

#!/usr/bin/env python3

# prevent local imports
if __name__ == "__main__":
    __import__('sys').path.pop(0)

import io
import math as mt
import os
import struct
import sys


# open with '-' for stdin/stdout
def openio(path, mode='r', buffering=-1):
    import os
    if path == '-':
        if 'r' in mode:
            return os.fdopen(os.dup(sys.stdin.fileno()), mode, buffering)
        else:
            return os.fdopen(os.dup(sys.stdout.fileno()), mode, buffering)
    else:
        return open(path, mode, buffering)

def dbg_le32s(data, *,
        word_bits=32):
    # figure out le32 size in bytes
    if word_bits != 0:
        n = mt.ceil(word_bits / 8)

    # parse le32s, or le<whatevers>
    lines = []
    j = 0
    while j < len(data):
        word = 0
        d = 0
        while (j+d < len(data)
                and (d < n if word_bits != 0 else True)):
            word |= data[j+d] << d
            d += 1

        lines.append((
                ' '.join('%02x' % b for b in data[j:j+d]),
                word))
        j += d

    # figure out widths
    w = [0]
    for l in lines:
        w[0] = max(w[0], len(l[0]))

    # then print results
    for l in lines:
        print('%-*s    %s' % (
                w[0], l[0],
                l[1]))

def main(le32s, *,
        hex=False,
        input=None,
        word_bits=32):
    import builtins
    hex_, hex = hex, builtins.hex

    # interpret as a sequence of hex bytes
    if hex_:
        bytes_ = [b for le32 in le32s for b in le32.split()]
        dbg_le32s(bytes(int(b, 16) for b in bytes_),
                word_bits=word_bits)

    # parse le32s in a file
    elif input:
        with openio(input, 'rb') as f:
            dbg_le32s(f.read(),
                    word_bits=word_bits)

    # we don't currently have a default interpretation
    else:
        print("error: no -x/--hex or -i/--input?",
                file=sys.stderr)
        sys.exit(1)


if __name__ == "__main__":
    import argparse
    import sys
    parser = argparse.ArgumentParser(
            description="Decode le32s.",
            allow_abbrev=False)
    parser.add_argument(
            'le32s',
            nargs='*',
            help="Le32s to decode.")
    parser.add_argument(
            '-x', '--hex',
            action='store_true',
            help="Interpret as a sequence of hex bytes.")
    parser.add_argument(
            '-i', '--input',
            help="Read le32s from this file. Can use - for stdin.")
    parser.add_argument(
            '-w', '--word', '--word-bits',
            dest='word_bits',
            nargs='?',
            type=lambda x: int(x, 0),
            const=0,
            help="Word size in bits. 0 is unbounded. Defaults to 32.")
    sys.exit(main(**{k: v
            for k, v in vars(parser.parse_intermixed_args()).items()
            if v is not None}))