18 lines
376 B
Python
18 lines
376 B
Python
"""Misc integer tools."""
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from fontTools.misc.py23 import *
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__all__ = ['popCount']
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def popCount(v):
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"""Return number of 1 bits in an integer."""
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if v > 0xFFFFFFFF:
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return popCount(v >> 32) + popCount(v & 0xFFFFFFFF)
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# HACKMEM 169
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y = (v >> 1) & 0xDB6DB6DB
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y = v - y - ((y >> 1) & 0xDB6DB6DB)
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return (((y + (y >> 3)) & 0xC71C71C7) % 0x3F)
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