a new day, a new s algo - fix #946
[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     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[]}|:;?/>.<",
9      "J:|}][{=+-_)(*&;%$#@>MNBVCXZASDFGH^KLPOIUYTREWQ0987654321mnbvcxzasdfghrklpoiuytej"),
10     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$^&*()_-+={[]}|:;?/>.<",
11      "!?;:|}][{=+-_)(*&^$#@/MNBVCXZASqFGHJKLPOIUYTREWQ0987654321mnbvcxzasdfghjklpoiuytr"),
12     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[|};?/>.<",
13      "ertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!/#$%^&*()_-+={[|};?@"),
14     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[};?/>.<",
15      "{>/?;}[.=+-_)(*&^%$#@!MqBVCXZASDFwHJKLPOIUYTREWQ0987654321mnbvcxzasdfghjklpoiuytr"),
16     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[};?>.<",
17      "<.>?;}[{=+-_)(*&^%$#@!MNBVCXZASDFGHJKLPOIUYTREWe098765432rmnbvcxzasdfghjklpoiuyt1"),
18     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!#$%^&*()_+={[};?/>.<",
19      "D.>/?;}[{=+_)(*&^%$#!MNBVCXeAS<FGHJKLPOIUYTREWZ0987654321mnbvcxzasdfghjklpoiuytrQ"),
20     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKHGFDSAZXCVBNM!@#$%^&*(-+={[};?/>.<",
21      "Q>/?;}[{=+-(*<^%$#@!MNBVCXZASDFGHKLPOIUY8REWT0q&7654321mnbvcxzasdfghjklpoiuytrew9"),
22 ]
23
24 def find_matching(wrong, right):
25     idxs = [wrong.index(c) for c in right]
26     return compress(idxs)
27     return ('s[%d]' % i for i in idxs)
28
29 def compress(idxs):
30     def _genslice(start, end, step):
31         starts = '' if start == 0 else str(start)
32         ends = ':%d' % (end+step)
33         steps = '' if step == 1 else (':%d' % step)
34         return 's[%s%s%s]' % (starts, ends, steps)
35
36     step = None
37     for i, prev in zip(idxs[1:], idxs[:-1]):
38         if step is not None:
39             if i - prev == step:
40                 continue
41             yield _genslice(start, prev, step)
42             step = None
43             continue
44         if i - prev in [-1, 1]:
45             step = i - prev
46             start = prev
47             continue
48         else:
49             yield 's[%d]' % prev
50     if step is None:
51         yield 's[%d]' % i
52     else:
53         yield _genslice(start, i, step)
54
55 def _assert_compress(inp, exp):
56     res = list(compress(inp))
57     if res != exp:
58         print('Got %r, expected %r' % (res, exp))
59         assert res == exp
60 _assert_compress([0,2,4,6], ['s[0]', 's[2]', 's[4]', 's[6]'])
61 _assert_compress([0,1,2,4,6,7], ['s[:3]', 's[4]', 's[6:8]'])
62 _assert_compress([8,0,1,2,4,7,6,9], ['s[8]', 's[:3]', 's[4]', 's[7:5:-1]', 's[9]'])
63
64 def gen(wrong, right, indent):
65     code = ' + '.join(find_matching(wrong, right))
66     return 'if len(s) == %d:\n%s    return %s\n' % (len(wrong), indent, code)
67
68 def genall(tests):
69     indent = ' ' * 8
70     return indent + (indent + 'el').join(gen(wrong, right, indent) for wrong,right in tests)
71
72 def main():
73     print(genall(tests))
74
75 if __name__ == '__main__':
76     main()