endolith/README.md

## README.md

      
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              README.md
            
          
    It's been a long time since I used this, and I don't remember its purpose.  I think it's for writing a binary file to an EEPROM, when the chip reading that EEPROM expects the bits in reversed order.
flip_bits.py can be used on a file directly, as well, though in the context of the script it just operates on temporary files:
python flip_bits.py infile outfile
I'm sure this could be done with a very simple C command line tool instead.  But hey, it works.

  
## flip_bits.e2s
#------ START --------
# PonyProg2000 script to flip the bit order of the bytes in
# a binary file before writing to an EEPROM
#
# Save data
SAVE-ALL ~tmpnormal.bin bin
# Flip bits of every byte
CALL "C:\Python37\python flip_bits.py ~tmpnormal.bin ~tmpflipped.bin"
# Reload data
LOAD-ALL ~tmpflipped.bin bin
#------- END ---------

## flip_bits.py
"""
Read in a binary file and flip the bit ordering of all the bytes (while
keeping the byte order the same).

Usage:

    python flip_bits.py infile outfile
"""
import sys


def flip_bits(b):
    """
    Reverse the bits of byte `b`.  `b` must be an int in the range [0, 255]

    From https://stackoverflow.com/a/2602885/125507
    """
    b = (b & 0xF0) >> 4 | (b & 0x0F) << 4
    b = (b & 0xCC) >> 2 | (b & 0x33) << 2
    b = (b & 0xAA) >> 1 | (b & 0x55) << 1
    return b


def test_flip_bits():
    for n in range(256):
        assert(f'{n:>08b}'[::-1] == f'{flip_bits(n):>08b}')


# TODO: There are more efficient ways to process files 1 byte at a time:
# https://stackoverflow.com/a/59013806/125507

fin = open(sys.argv[1], 'rb')
fout = open(sys.argv[2], 'wb')

while True:
    byte = fin.read(1)

    # Quit at end of file
    if byte == b'':
        break

    # Flip bits
    flipped = flip_bits(byte[0])

    # Write flipped int to output file
    fout.write(bytes((flipped,)))

fin.close()
fout.close()
	#------ START --------
	# PonyProg2000 script to flip the bit order of the bytes in
	# a binary file before writing to an EEPROM
	#
	# Save data
	SAVE-ALL ~tmpnormal.bin bin
	# Flip bits of every byte
	CALL "C:\Python37\python flip_bits.py ~tmpnormal.bin ~tmpflipped.bin"
	# Reload data
	LOAD-ALL ~tmpflipped.bin bin
	#------- END ---------
	"""
	Read in a binary file and flip the bit ordering of all the bytes (while
	keeping the byte order the same).

	Usage:

	python flip_bits.py infile outfile
	"""
	import sys


	def flip_bits(b):
	"""
	Reverse the bits of byte `b`. `b` must be an int in the range [0, 255]

	From https://stackoverflow.com/a/2602885/125507
	"""
	b = (b & 0xF0) >> 4 \| (b & 0x0F) << 4
	b = (b & 0xCC) >> 2 \| (b & 0x33) << 2
	b = (b & 0xAA) >> 1 \| (b & 0x55) << 1
	return b


	def test_flip_bits():
	for n in range(256):
	assert(f'{n:>08b}'[::-1] == f'{flip_bits(n):>08b}')


	# TODO: There are more efficient ways to process files 1 byte at a time:
	# https://stackoverflow.com/a/59013806/125507

	fin = open(sys.argv[1], 'rb')
	fout = open(sys.argv[2], 'wb')

	while True:
	byte = fin.read(1)

	# Quit at end of file
	if byte == b'':
	break

	# Flip bits
	flipped = flip_bits(byte[0])

	# Write flipped int to output file
	fout.write(bytes((flipped,)))

	fin.close()
	fout.close()