150c88d1754c4cfcb6f79b20ef559406f0dc2937
[youtube-dl] / devscripts / youtube_genalgo.py
1 #!/usr/bin/env python
2
3 # Generate youtube signature algorithm from test cases
4
5 import sys
6
7 tests = [
8     # 88
9     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[]}|:;?/>.<",
10      "J:|}][{=+-_)(*&;%$#@>MNBVCXZASDFGH^KLPOIUYTREWQ0987654321mnbvcxzasdfghrklpoiuytej"),
11     # 87
12     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$^&*()_-+={[]}|:;?/>.<",
13      "!?;:|}][{=+-_)(*&^$#@/MNBVCXZASqFGHJKLPOIUYTREWQ0987654321mnbvcxzasdfghjklpoiuytr"),
14     # 86 - vfl_ymO4Z 2013/06/27
15     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[|};?/>.<",
16      "ertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!/#$%^&*()_-+={[|};?@"),
17     # 85
18     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[};?/>.<",
19      "{>/?;}[.=+-_)(*&^%$#@!MqBVCXZASDFwHJKLPOIUYTREWQ0987654321mnbvcxzasdfghjklpoiuytr"),
20     # 84
21     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[};?>.<",
22      "<.>?;}[{=+-_)(*&^%$#@!MNBVCXZASDFGHJKLPOIUYTREWe098765432rmnbvcxzasdfghjklpoiuyt1"),
23     # 83 - vfl26ng3K 2013/07/10
24     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!#$%^&*()_+={[};?/>.<",
25      "qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!#$%^&*()_+={[};?/>"),
26     # 82
27     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKHGFDSAZXCVBNM!@#$%^&*(-+={[};?/>.<",
28      "Q>/?;}[{=+-(*<^%$#@!MNBVCXZASDFGHKLPOIUY8REWT0q&7654321mnbvcxzasdfghjklpoiuytrew9"),
29 ]
30
31 def find_matching(wrong, right):
32     idxs = [wrong.index(c) for c in right]
33     return compress(idxs)
34     return ('s[%d]' % i for i in idxs)
35
36 def compress(idxs):
37     def _genslice(start, end, step):
38         starts = '' if start == 0 else str(start)
39         ends = ':%d' % (end+step)
40         steps = '' if step == 1 else (':%d' % step)
41         return 's[%s%s%s]' % (starts, ends, steps)
42
43     step = None
44     for i, prev in zip(idxs[1:], idxs[:-1]):
45         if step is not None:
46             if i - prev == step:
47                 continue
48             yield _genslice(start, prev, step)
49             step = None
50             continue
51         if i - prev in [-1, 1]:
52             step = i - prev
53             start = prev
54             continue
55         else:
56             yield 's[%d]' % prev
57     if step is None:
58         yield 's[%d]' % i
59     else:
60         yield _genslice(start, i, step)
61
62 def _assert_compress(inp, exp):
63     res = list(compress(inp))
64     if res != exp:
65         print('Got %r, expected %r' % (res, exp))
66         assert res == exp
67 _assert_compress([0,2,4,6], ['s[0]', 's[2]', 's[4]', 's[6]'])
68 _assert_compress([0,1,2,4,6,7], ['s[:3]', 's[4]', 's[6:8]'])
69 _assert_compress([8,0,1,2,4,7,6,9], ['s[8]', 's[:3]', 's[4]', 's[7:5:-1]', 's[9]'])
70
71 def gen(wrong, right, indent):
72     code = ' + '.join(find_matching(wrong, right))
73     return 'if len(s) == %d:\n%s    return %s\n' % (len(wrong), indent, code)
74
75 def genall(tests):
76     indent = ' ' * 8
77     return indent + (indent + 'el').join(gen(wrong, right, indent) for wrong,right in tests)
78
79 def main():
80     print(genall(tests))
81
82 if __name__ == '__main__':
83     main()