Count Leading Zeros (CLZ) for sparse files

sparse_clz.py

import os
import sys

def count_continuous(data, value):
    for i in range(len(data)):
        if data[i] != value: break
    return i

def sparse_clz(filename, blocksize):
    fd     = os.open(filename, os.O_RDONLY)
    offset = os.lseek(fd, 0, os.SEEK_DATA)
    while True:
        data    = os.read(fd, blocksize)
        if not data: break
        count   = count_continuous(data, 0)
        offset += count
        if count != len(data): break
    os.close(fd)
    return offset

if __name__ == '__main__':
    argc      = len(sys.argv)
    filename  =     sys.argv[1]
    blocksize = int(sys.argv[2]) if argc > 2 else 4096
    res       = sparse_clz(filename, blocksize)
    print(res)

sparse_clz_bisect.py

import os
import sys
import bisect

def sparse_clz(filename, blocksize):
    fd     = os.open(filename, os.O_RDONLY)
    offset = os.lseek(fd, 0, os.SEEK_DATA)
    while True:
        data    = os.read(fd, blocksize)
        if not data: break
        count   = bisect.bisect_right(data, 0)
        offset += count
        if count != len(data): break
    os.close(fd)
    return offset

if __name__ == '__main__':
    argc      = len(sys.argv)
    filename  =     sys.argv[1]
    blocksize = int(sys.argv[2]) if argc > 2 else 4096
    res       = sparse_clz(filename, blocksize)
    print(res)