Read microcontroller eeprom and feed into python to find checksums.

[mikeak2001]

Thank you for the reply.

The package has helped a lot, I can now find the checksums and log the start and end of the data blocks.
Can anyone give me some pointers of speeding up this script. I am reading a 2048kb file and calculating all data blocks with their checksums. However it is so so slow. Running the script on the file for 24hrs and the script only read through 23% of the file, I don't really want to be running the computer for 4 days on each file if I can cut down the time.
My coding is as below:

#!/usr/bin/python

import os
import sys
import crcengine

def progress(count, total, suffix=''):
    bar_len = 60
    filled_len = int(round(bar_len * count / float(total)))

    percents = round(100.0 * count / float(total), 1)
    bar = '=' * filled_len + '-' * (bar_len - filled_len)

    sys.stdout.write('[%s] %s%s ...%s\r' % (bar, percents, '%', suffix))
    sys.stdout.flush()


def main(argv):
	inputfile = sys.argv[1]
	inputfilesize = os.path.getsize(sys.argv[1])
	outputfile = sys.argv[1]+'.txt'
	woutputfiledata = open(outputfile, 'a+')

	print ('Input file is:' + inputfile)
	print ('Finding checksums...')

	f1 = open(inputfile, "rb")   	# open argv[1] file for binary reading
									#
	block = 1						# used to keep track of found blocks - increments
	previousPos = 0					# starts at zero - increments by amount of bytes found in each block
	currentPos = 0					# current byte position within the file
	bytelist = []					# bytes currently read
	message = b''					# hex string passed to the crcengine function
	chkmessage = b''				# calculated checksum of bytelist and message used to see if it equal to the last two bytes
	CRCcheck = ['00','00']			# last two bytes of bytelist - compared to the checksum of bytelist[-2]
	CRCcheckMessage = 'CRC=0x'			# CRCcheckMessage to compare to chkmessage
	crc_algorithm = crcengine.new('crc16-ccitt-false')	# set up crc algorithm
	successcounter = 0
	
	while 1:
		byte_s = f1.read(1)		# read 1 byte from the file
		if not byte_s:			# if no bytes read quit
			f1.close()
			break
			
		bytelist.append(byte_s)  # add read byte to bytelist
		
		while len(bytelist) < 3: 	# check theres at least 3 bytes
			byte_s = f1.read(1)		# last two are used as the checksum comparitor
			currentPos +=1			# increase currentPos to keep track of bytes read and position within file
			bytelist.append(byte_s) # then add the byte to bytelist
			
		CRCcheck[0] = bytelist[-2]	# add last but one byte read to the first position of the checksum list
		CRCcheck[1] = bytelist[-1]	# add last bite read to the second position of the checksum list
		message = message + bytelist[-3]	# add all bytes bar the last two to the byte string
		result = crc_algorithm(message)		# send the byte string and store the returned checksum int into result
		chkmessage ='CRC=0x{:04x}'.format(result)	# convert checksum message into a 2 byte hex string
		
		CRCcheckMessage = CRCcheckMessage + CRCcheck[0].hex()
		CRCcheckMessage = CRCcheckMessage + CRCcheck[1].hex()
		
		if CRCcheckMessage == chkmessage:
			woutputfiledata.write('BLK: '+ str(block)+'\n')
			woutputfiledata.write('SOB: '+ '0x{:08x}'.format(previousPos)+'\n')
			woutputfiledata.write('EOB: '+ '0x{:08x}'.format(currentPos-2)+'\n')
			woutputfiledata.write('CKS: '+ chkmessage+'\n')
			woutputfiledata.write('\n')
			block += 1
			successcounter += 1
			previousPos = currentPos + 1
			bytelist.clear()
			
		CRCcheckMessage = 'CRC=0x'
		currentPos +=1
		progress(currentPos, inputfilesize)

if __name__ == "__main__":
	main(sys.argv[1:])

I will only ever have to read a file once, when I have all the checksums I will be able to just mod a particular block and recalculate that blocks checksum.

The script ouputs to a txt file like below:

BLK: 1
SOB: 0x00000000
EOB: 0x000084fb
CKS: CRC=0x1a49

BLK: 2
SOB: 0x000084fe
EOB: 0x00039b34
CKS: CRC=0x4444

BLK: 3
SOB: 0x00039b37
EOB: 0x0006d4cb
CKS: CRC=0xffff

BLK: 4
SOB: 0x0006d4ce
EOB: 0x000754cc
CKS: CRC=0xffff

This is the last file I tried and it seems to be working from manually checking the file locations. I just need to be able to run through the file quicker.