hashall.h

来自「经典numerical receip 配套代码」· C头文件 代码 · 共 33 行

void psdes(Uint &lword, Uint &rword) {
	const int NITER=2;
	static const Uint c1[4]={
		0xbaa96887L, 0x1e17d32cL, 0x03bcdc3cL, 0x0f33d1b2L};
	static const Uint c2[4]={
		0x4b0f3b58L, 0xe874f0c3L, 0x6955c5a6L, 0x55a7ca46L};
	Uint i,ia,ib,iswap,itmph=0,itmpl=0;
	for (i=0;i<NITER;i++) {
		ia = (iswap=rword) ^ c1[i];
		itmpl = ia & 0xffff;
		itmph = ia >> 16;
		ib=itmpl*itmpl+ ~(itmph*itmph);
		rword = lword ^ (((ia = (ib >> 16) |
			((ib & 0xffff) << 16)) ^ c2[i])+itmpl*itmph);
		lword = iswap;
	}
}
void hashall(VecUint &arr) {
	Int m=arr.size(), n=m-1;
	n|=n>>1; n|=n>>2; n|=n>>4; n|=n>>8; n|=n>>16; n++;
	Int nb=n,nb2=n>>1,j,jb;
	if (n<2) throw("size must be > 1");
	while (nb > 1) {
		for (jb=0;jb<n-nb+1;jb+=nb)
			for (j=0;j<nb2;j++)
				if (jb+j+nb2 < m) psdes(arr[jb+j],arr[jb+j+nb2]);
		nb = nb2;
		nb2 >>= 1;
	}
	nb2 = n>>1;
	if (m != n) for (j=nb2;j<m;j++) psdes(arr[j],arr[j-nb2]);
}