scripts to test reading y-cruncher digit .ycd files

p1.py

import sys

DIGITS = int(sys.argv[1])
assert DIGITS > 0 and DIGITS <= 6
outfile = open(sys.argv[2],'w')

# use sliding window of digits
offset = 1
window = sys.stdin.read(DIGITS)
assert len(window) == DIGITS
assert type(window) == str

# store offsets, 0 = not found
results = [0] * (10**DIGITS)
results[int(window)] = 1

while True:
    nextdigit = sys.stdin.read(1)
    if nextdigit == '': break
    offset += 1
    window = window[1:] + nextdigit
    number = int(window)
    if results[number] == 0:
        results[number] = offset

# write output in "sequence:offset" format
for i in range(10**DIGITS):
    outfile.write(('%%0%dd:%%d\n'%DIGITS)%(i,results[i]))
outfile.close()

p2.py

infile = open(sys.argv[1],'rb')
digits = int(sys.argv[2])
radix = sys.argv[3].lower()

# get past null character that ends the header
while infile.read(1) != b'\x00': pass

# read digits up to limit specified
# does not care about y-cruncher format which may include garbage data as
# padding beyond the end of the digits stored
# if too many digits are specified, it will have an error when reaching eof

if radix == 'dec':
    while True:
        if digits <= 0: break
        value = struct.unpack('<q',infile.read(8))[0]%(2**64)
        outstr = '%019d'%value
        sys.stdout.write(outstr[:min(19,digits)])
        digits -= 19

elif radix == 'hex':
    while True:
        if digits <= 0: break
        value = struct.unpack('<q',infile.read(8))[0]%(2**64)
        outstr = '%016x'%value
        sys.stdout.write(outstr[:min(16,digits)])
        digits -= 16

else: assert 0