+#!/usr/bin/env python
+
+# Generate youtube signature algorithm from test cases
+
+import sys
+
+tests = [
+ ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[]}|:;?/>.<",
+ "J:|}][{=+-_)(*&;%$#@>MNBVCXZASDFGH^KLPOIUYTREWQ0987654321mnbvcxzasdfghrklpoiuytej"),
+ ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$^&*()_-+={[]}|:;?/>.<",
+ "!?;:|}][{=+-_)(*&^$#@/MNBVCXZASqFGHJKLPOIUYTREWQ0987654321mnbvcxzasdfghjklpoiuytr"),
+ ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[|};?/>.<",
+ "ertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!/#$%^&*()_-+={[|};?@"),
+ ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[};?/>.<",
+ "{>/?;}[.=+-_)(*&^%$#@!MqBVCXZASDFwHJKLPOIUYTREWQ0987654321mnbvcxzasdfghjklpoiuytr"),
+ ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[};?>.<",
+ "<.>?;}[{=+-_)(*&^%$#@!MNBVCXZASDFGHJKLPOIUYTREWe098765432rmnbvcxzasdfghjklpoiuyt1"),
+ ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!#$%^&*()_+={[};?/>.<",
+ "D.>/?;}[{=+_)(*&^%$#!MNBVCXeAS<FGHJKLPOIUYTREWZ0987654321mnbvcxzasdfghjklpoiuytrQ"),
+ ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKHGFDSAZXCVBNM!@#$%^&*(-+={[};?/>.<",
+ "Q>/?;}[{=+-(*<^%$#@!MNBVCXZASDFGHKLPOIUY8REWT0q&7654321mnbvcxzasdfghjklpoiuytrew9"),
+]
+
+def find_matching(wrong, right):
+ idxs = [wrong.index(c) for c in right]
+ return compress(idxs)
+ return ('s[%d]' % i for i in idxs)
+
+def compress(idxs):
+ def _genslice(start, end, step):
+ starts = '' if start == 0 else str(start)
+ ends = ':%d' % (end+step)
+ steps = '' if step == 1 else (':%d' % step)
+ return 's[%s%s%s]' % (starts, ends, steps)
+
+ step = None
+ for i, prev in zip(idxs[1:], idxs[:-1]):
+ if step is not None:
+ if i - prev == step:
+ continue
+ yield _genslice(start, prev, step)
+ step = None
+ continue
+ if i - prev in [-1, 1]:
+ step = i - prev
+ start = prev
+ continue
+ else:
+ yield 's[%d]' % prev
+ if step is None:
+ yield 's[%d]' % i
+ else:
+ yield _genslice(start, i, step)
+
+def _assert_compress(inp, exp):
+ res = list(compress(inp))
+ if res != exp:
+ print('Got %r, expected %r' % (res, exp))
+ assert res == exp
+_assert_compress([0,2,4,6], ['s[0]', 's[2]', 's[4]', 's[6]'])
+_assert_compress([0,1,2,4,6,7], ['s[:3]', 's[4]', 's[6:8]'])
+_assert_compress([8,0,1,2,4,7,6,9], ['s[8]', 's[:3]', 's[4]', 's[7:5:-1]', 's[9]'])
+
+def gen(wrong, right, indent):
+ code = ' + '.join(find_matching(wrong, right))
+ return 'if len(s) == %d:\n%s return %s\n' % (len(wrong), indent, code)
+
+def genall(tests):
+ indent = ' ' * 8
+ return indent + (indent + 'el').join(gen(wrong, right, indent) for wrong,right in tests)
+
+def main():
+ print(genall(tests))
+
+if __name__ == '__main__':
+ main()