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author | toma <toma@283d02a7-25f6-0310-bc7c-ecb5cbfe19da> | 2009-11-25 17:56:58 +0000 |
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committer | toma <toma@283d02a7-25f6-0310-bc7c-ecb5cbfe19da> | 2009-11-25 17:56:58 +0000 |
commit | c90c389a8a8d9d8661e9772ec4144c5cf2039f23 (patch) | |
tree | 6d8391395bce9eaea4ad78958617edb20c6a7573 /kpat/freecell-solver/lookup2.c | |
download | tdegames-c90c389a8a8d9d8661e9772ec4144c5cf2039f23.tar.gz tdegames-c90c389a8a8d9d8661e9772ec4144c5cf2039f23.zip |
Copy the KDE 3.5 branch to branches/trinity for new KDE 3.5 features.
BUG:215923
git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/kdegames@1054174 283d02a7-25f6-0310-bc7c-ecb5cbfe19da
Diffstat (limited to 'kpat/freecell-solver/lookup2.c')
-rw-r--r-- | kpat/freecell-solver/lookup2.c | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/kpat/freecell-solver/lookup2.c b/kpat/freecell-solver/lookup2.c new file mode 100644 index 00000000..6ab9ae7e --- /dev/null +++ b/kpat/freecell-solver/lookup2.c @@ -0,0 +1,119 @@ +/* +-------------------------------------------------------------------- +lookup2.c, by Bob Jenkins, December 1996, Public Domain. +hash(), hash2(), hash3, and mix() are externally useful functions. +Routines to test the hash are included if SELF_TEST is defined. +You can use this free for any purpose. It has no warranty. +-------------------------------------------------------------------- + +Note: + This code was ripped and modified by Shlomi Fish. The original can + be found at http://burtleburtle.net/bob/c/lookup2.c. +*/ + +#include <stdio.h> +#include <stddef.h> +#include <stdlib.h> + +#include "lookup2.h" + + +#define hashsize(n) ((ub4)1<<(n)) +#define hashmask(n) (hashsize(n)-1) + +/* +-------------------------------------------------------------------- +mix -- mix 3 32-bit values reversibly. +For every delta with one or two bit set, and the deltas of all three + high bits or all three low bits, whether the original value of a,b,c + is almost all zero or is uniformly distributed, +* If mix() is run forward or backward, at least 32 bits in a,b,c + have at least 1/4 probability of changing. +* If mix() is run forward, every bit of c will change between 1/3 and + 2/3 of the time. (Well, 22/100 and 78/100 for some 2-bit deltas.) +mix() was built out of 36 single-cycle latency instructions in a + structure that could supported 2x parallelism, like so: + a -= b; + a -= c; x = (c>>13); + b -= c; a ^= x; + b -= a; x = (a<<8); + c -= a; b ^= x; + c -= b; x = (b>>13); + ... + Unfortunately, superscalar Pentiums and Sparcs can't take advantage + of that parallelism. They've also turned some of those single-cycle + latency instructions into multi-cycle latency instructions. Still, + this is the fastest good hash I could find. There were about 2^^68 + to choose from. I only looked at a billion or so. +-------------------------------------------------------------------- +*/ +#define mix(a,b,c) \ +{ \ + a -= b; a -= c; a ^= (c>>13); \ + b -= c; b -= a; b ^= (a<<8); \ + c -= a; c -= b; c ^= (b>>13); \ + a -= b; a -= c; a ^= (c>>12); \ + b -= c; b -= a; b ^= (a<<16); \ + c -= a; c -= b; c ^= (b>>5); \ + a -= b; a -= c; a ^= (c>>3); \ + b -= c; b -= a; b ^= (a<<10); \ + c -= a; c -= b; c ^= (b>>15); \ +} + +/* +-------------------------------------------------------------------- + This works on all machines. hash2() is identical to hash() on + little-endian machines, except that the length has to be measured + in ub4s instead of bytes. It is much faster than hash(). It + requires + -- that the key be an array of ub4's, and + -- that all your machines have the same endianness, and + -- that the length be the number of ub4's in the key +-------------------------------------------------------------------- +*/ + +ub4 freecell_solver_lookup2_hash_function( + register ub1 *k, /* the key */ + register ub4 length, /* the length of the key */ + register ub4 initval /* the previous hash, or an arbitrary value */ + ) +{ + register ub4 a,b,c,len; + + /* Set up the internal state */ + len = length; + a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */ + c = initval; /* the previous hash value */ + + /*---------------------------------------- handle most of the key */ + while (len >= 12) + { + a += (k[0] +((ub4)k[1]<<8) +((ub4)k[2]<<16) +((ub4)k[3]<<24)); + b += (k[4] +((ub4)k[5]<<8) +((ub4)k[6]<<16) +((ub4)k[7]<<24)); + c += (k[8] +((ub4)k[9]<<8) +((ub4)k[10]<<16)+((ub4)k[11]<<24)); + mix(a,b,c); + k += 12; len -= 12; + } + + /*------------------------------------- handle the last 11 bytes */ + c += length; + switch(len) /* all the case statements fall through */ + { + case 11: c+=((ub4)k[10]<<24); + case 10: c+=((ub4)k[9]<<16); + case 9 : c+=((ub4)k[8]<<8); + /* the first byte of c is reserved for the length */ + case 8 : b+=((ub4)k[7]<<24); + case 7 : b+=((ub4)k[6]<<16); + case 6 : b+=((ub4)k[5]<<8); + case 5 : b+=k[4]; + case 4 : a+=((ub4)k[3]<<24); + case 3 : a+=((ub4)k[2]<<16); + case 2 : a+=((ub4)k[1]<<8); + case 1 : a+=k[0]; + /* case 0: nothing left to add */ + } + mix(a,b,c); + /*-------------------------------------------- report the result */ + return c; +} |