#! /usr/bin/env python

import sys, os, random

if __name__ == '__main__':

    fbuff = 2**28   # file buffer size in bytes
    fints = 10**8   # number of integers to write
    fsize = 12      # number of digits to write per integer
    
    fname = os.path.splitext(os.path.basename(sys.argv[0]))[0]
    try:
        os.mkdir(fname)
    except OSError:
        pass    # directory already exists
        
    fpath = os.path.join(fname, fname+'.dat')
    fhand = open(fpath, 'w', fbuff)
    
    sys.stdout.write('Writing %d MB to file \'%s\'\n' % (fints*(fsize+1)/10**6, fpath))
    sys.stdout.write('This will take some time, please wait.\n')
    sys.stdout.write('Progress:')
    sys.stdout.flush()

    random.seed(-1)
    fform = '%'+str(fsize)+'d\n'
    for x in xrange(fints): 
        fhand.write(fform % (random.randint(0,fints)))
        if x % (fints/10) == 0 and x > 0:
            sys.stdout.write('%3d/10' % (x/(fints/10))) 
            sys.stdout.flush()

    sys.stdout.write(' 10/10\n')
    sys.stdout.flush()
    fhand.close()