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(svn r11538) -Codechange: Rewrite GetNthSetBit in a more uncontroversial way and add its documentation

This commit is contained in:
skidd13 2007-11-28 21:59:06 +00:00
parent 981865dbcc
commit 6e511188ae
1 changed files with 13 additions and 6 deletions
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19
src/town_gui.cpp
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@ -109,15 +109,22 @@ uint GetMaskOfTownActions(int *nump, PlayerID pid, const Town *t)
return buttons;
}
/**
* Get the position of the Nth set bit.
*
* If there is no Nth bit set return -1
*
* @param bits The value to search in
* @param n The Nth set bit from which we want to know the position
* @return The position of the Nth set bit
*/
static int GetNthSetBit(uint32 bits, int n)
{
int i = 0;
if (n >= 0) {
do {
if (bits & 1 && --n < 0) return i;
i++;
} while (bits >>= 1);
for (uint i = 0; bits != 0; bits >>= 1, i++) {
if (bits & 1) n--;
if (n < 0) return i;
}
}
return -1;
}