split a file into multiple parts by bytes

splitfile.py

def split_file(file, prefix, max_size, buffer=1024):
"""
filename: the input filename
max_size: maximum size of each created file in bytes
buffer: buffer size in bytes

Returns the number of parts created.
"""
with open(file, 'r+b') as src:
    suffix = 0
    while True:
        with open(filename + '.%s' % suffix, 'w+b') as tgt:
            written = 0
            while written <= max_size:
                data = src.read(buffer)
                if data:
                    tgt.write(data)
                    written += buffer
                else:
                    return suffix
            suffix += 1