/*
 * -------------------------------------------------------------------------------
 * lookup3.c, by Bob Jenkins, May 2006, Public Domain.
 *
 * These are functions for producing 32-bit hashes for hash table lookup.
 * hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final()
 * 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's in
 * the public domain.  It has no warranty.
 *
 * You probably want to use hashlittle().  hashlittle() and hashbig()
 * hash byte arrays.  hashlittle() is is faster than hashbig() on
 * little-endian machines.  Intel and AMD are little-endian machines.
 * On second thought, you probably want hashlittle2(), which is identical to
 * hashlittle() except it returns two 32-bit hashes for the price of one.
 * You could implement hashbig2() if you wanted but I haven't bothered here.
 *
 * If you want to find a hash of, say, exactly 7 integers, do
 * a = i1;  b = i2;  c = i3;
 * mix(a,b,c);
 * a += i4; b += i5; c += i6;
 * mix(a,b,c);
 * a += i7;
 * final(a,b,c);
 * then use c as the hash value.  If you have a variable length array of
 * 4-byte integers to hash, use hashword().  If you have a byte array (like
 * a character string), use hashlittle().  If you have several byte arrays, or
 * a mix of things, see the comments above hashlittle().
 *
 * Why is this so big?  I read 12 bytes at a time into 3 4-byte integers,
 * then mix those integers.  This is fast (you can do a lot more thorough
 * mixing with 12*3 instructions on 3 integers than you can with 3 instructions
 * on 1 byte), but shoehorning those bytes into integers efficiently is messy.
 * -------------------------------------------------------------------------------
 */

/* #define SELF_TEST 1 */

#include <stdio.h>      /* defines printf for tests */
#include <time.h>       /* defines time_t for timings in the test */
#include <stdint.h>     /* defines uint32_t etc */
#include <sys/param.h>  /* attempt to define endianness */
#ifdef linux
# include <endian.h>    /* attempt to define endianness */
#endif

#include "lookup3.h"

/*
 * My best guess at if you are big-endian or little-endian.  This may
 * need adjustment.
 */
#if (defined(__BYTE_ORDER) && defined(__LITTLE_ENDIAN) && \
	__BYTE_ORDER == __LITTLE_ENDIAN) || \
	(defined(i386) || defined(__i386__) || defined(__i486__) || \
	defined(__i586__) || defined(__i686__) || defined(vax) || defined(MIPSEL))
# define HASH_LITTLE_ENDIAN 1
# define HASH_BIG_ENDIAN 0
#elif (defined(__BYTE_ORDER) && defined(__BIG_ENDIAN) && \
	__BYTE_ORDER == __BIG_ENDIAN) || \
	(defined(sparc) || defined(POWERPC) || defined(mc68000) || defined(sel))
# define HASH_LITTLE_ENDIAN 0
# define HASH_BIG_ENDIAN 1
#else
# define HASH_LITTLE_ENDIAN 0
# define HASH_BIG_ENDIAN 0
#endif

#define hashsize(n) ((uint32_t) 1 << (n))
#define hashmask(n) (hashsize(n) - 1)
#define rot(x, k) (((x) << (k)) | ((x) >> (32 - (k))))

/*
 * -------------------------------------------------------------------------------
 * mix -- mix 3 32-bit values reversibly.
 *
 * This is reversible, so any information in (a,b,c) before mix() is
 * still in (a,b,c) after mix().
 *
 * If four pairs of (a,b,c) inputs are run through mix(), or through
 * mix() in reverse, there are at least 32 bits of the output that
 * are sometimes the same for one pair and different for another pair.
 * This was tested for:
 * pairs that differed by one bit, by two bits, in any combination
 * of top bits of (a,b,c), or in any combination of bottom bits of
 * (a,b,c).
 * "differ" is defined as +, -, ^, or ~^.  For + and -, I transformed
 * the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
 * is commonly produced by subtraction) look like a single 1-bit
 * difference.
 * the base values were pseudorandom, all zero but one bit set, or
 * all zero plus a counter that starts at zero.
 *
 * Some k values for my "a-=c; a^=rot(c,k); c+=b;" arrangement that
 * satisfy this are
 *  4  6  8 16 19  4
 *  9 15  3 18 27 15
 * 14  9  3  7 17  3
 * Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing
 * for "differ" defined as + with a one-bit base and a two-bit delta.  I
 * used http://burtleburtle.net/bob/hash/avalanche.html to choose
 * the operations, constants, and arrangements of the variables.
 *
 * This does not achieve avalanche.  There are input bits of (a,b,c)
 * that fail to affect some output bits of (a,b,c), especially of a.  The
 * most thoroughly mixed value is c, but it doesn't really even achieve
 * avalanche in c.
 *
 * This allows some parallelism.  Read-after-writes are good at doubling
 * the number of bits affected, so the goal of mixing pulls in the opposite
 * direction as the goal of parallelism.  I did what I could.  Rotates
 * seem to cost as much as shifts on every machine I could lay my hands
 * on, and rotates are much kinder to the top and bottom bits, so I used
 * rotates.
 * -------------------------------------------------------------------------------
 */
#define mix(a, b, c) \
	{ \
		a -= c;  a ^= rot(c, 4);  c += b; \
		b -= a;  b ^= rot(a, 6);  a += c; \
		c -= b;  c ^= rot(b, 8);  b += a; \
		a -= c;  a ^= rot(c, 16);  c += b; \
		b -= a;  b ^= rot(a, 19);  a += c; \
		c -= b;  c ^= rot(b, 4);  b += a; \
	}

/*
 * -------------------------------------------------------------------------------
 * final -- final mixing of 3 32-bit values (a,b,c) into c
 *
 * Pairs of (a,b,c) values differing in only a few bits will usually
 * produce values of c that look totally different.  This was tested for
 * pairs that differed by one bit, by two bits, in any combination
 * of top bits of (a,b,c), or in any combination of bottom bits of
 * (a,b,c).
 * "differ" is defined as +, -, ^, or ~^.  For + and -, I transformed
 * the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
 * is commonly produced by subtraction) look like a single 1-bit
 * difference.
 * the base values were pseudorandom, all zero but one bit set, or
 * all zero plus a counter that starts at zero.
 *
 * These constants passed:
 * 14 11 25 16 4 14 24
 * 12 14 25 16 4 14 24
 * and these came close:
 * 4  8 15 26 3 22 24
 * 10  8 15 26 3 22 24
 * 11  8 15 26 3 22 24
 * -------------------------------------------------------------------------------
 */
#define final(a, b, c) \
	{ \
		c ^= b; c -= rot(b, 14); \
		a ^= c; a -= rot(c, 11); \
		b ^= a; b -= rot(a, 25); \
		c ^= b; c -= rot(b, 16); \
		a ^= c; a -= rot(c, 4); \
		b ^= a; b -= rot(a, 14); \
		c ^= b; c -= rot(b, 24); \
	}

/*
 * --------------------------------------------------------------------
 * This works on all machines.  To be useful, it requires
 * -- that the key be an array of uint32_t's, and
 * -- that the length be the number of uint32_t's in the key
 *
 * The function hashword() is identical to hashlittle() on little-endian
 * machines, and identical to hashbig() on big-endian machines,
 * except that the length has to be measured in uint32_ts rather than in
 * bytes.  hashlittle() is more complicated than hashword() only because
 * hashlittle() has to dance around fitting the key bytes into registers.
 * --------------------------------------------------------------------
 */
uint32_t
hashword(const uint32_t *k,          /* the key, an array of uint32_t values */
		 size_t length,               /* the length of the key, in uint32_ts */
		 uint32_t initval)       /* the previous hash, or an arbitrary value */
{
	uint32_t a, b, c;

	/* Set up the internal state */
	a = b = c = 0xdeadbeef + (((uint32_t) length) << 2) + initval;

	/*------------------------------------------------- handle most of the key */
	while (length > 3)
	{
		a += k[0];
		b += k[1];
		c += k[2];
		mix(a, b, c);
		length -= 3;
		k += 3;
	}

	/*------------------------------------------- handle the last 3 uint32_t's */
	switch (length)                  /* all the case statements fall through */
	{
		case 3:
		{
			c += k[2];
		}

		case 2:
		{
			b += k[1];
		}

		case 1:
		{
			a += k[0];
			final(a, b, c);
		}

		case 0: /* case 0: nothing left to add */
		{
			break;
		}
	}

	/*------------------------------------------------------ report the result */
	return c;
}


/*
 * --------------------------------------------------------------------
 * hashword2() -- same as hashword(), but take two seeds and return two
 * 32-bit values.  pc and pb must both be nonnull, and *pc and *pb must
 * both be initialized with seeds.  If you pass in (*pb)==0, the output
 * (*pc) will be the same as the return value from hashword().
 * --------------------------------------------------------------------
 */
void
hashword2(const uint32_t *k,         /* the key, an array of uint32_t values */
		  size_t length,              /* the length of the key, in uint32_ts */
		  uint32_t *pc,                  /* IN: seed OUT: primary hash value */
		  uint32_t *pb)           /* IN: more seed OUT: secondary hash value */
{
	uint32_t a, b, c;

	/* Set up the internal state */
	a = b = c = 0xdeadbeef + ((uint32_t) (length << 2)) + *pc;
	c += *pb;

	/*------------------------------------------------- handle most of the key */
	while (length > 3)
	{
		a += k[0];
		b += k[1];
		c += k[2];
		mix(a, b, c);
		length -= 3;
		k += 3;
	}

	/*------------------------------------------- handle the last 3 uint32_t's */
	switch (length)                  /* all the case statements fall through */
	{
		case 3:
		{
			c += k[2];
		}

		case 2:
		{
			b += k[1];
		}

		case 1:
		{
			a += k[0];
			final(a, b, c);
		}

		case 0: /* case 0: nothing left to add */
		{
			break;
		}
	}

	/*------------------------------------------------------ report the result */
	*pc = c;
	*pb = b;
}


/*
 * -------------------------------------------------------------------------------
 * hashlittle() -- hash a variable-length key into a 32-bit value
 * k       : the key (the unaligned variable-length array of bytes)
 * length  : the length of the key, counting by bytes
 * initval : can be any 4-byte value
 * Returns a 32-bit value.  Every bit of the key affects every bit of
 * the return value.  Two keys differing by one or two bits will have
 * totally different hash values.
 *
 * The best hash table sizes are powers of 2.  There is no need to do
 * mod a prime (mod is sooo slow!).  If you need less than 32 bits,
 * use a bitmask.  For example, if you need only 10 bits, do
 * h = (h & hashmask(10));
 * In which case, the hash table should have hashsize(10) elements.
 *
 * If you are hashing n strings (uint8_t **)k, do it like this:
 * for (i=0, h=0; i<n; ++i) h = hashlittle( k[i], len[i], h);
 *
 * By Bob Jenkins, 2006.  bob_jenkins@burtleburtle.net.  You may use this
 * code any way you wish, private, educational, or commercial.  It's free.
 *
 * Use for hash table lookup, or anything where one collision in 2^^32 is
 * acceptable.  Do NOT use for cryptographic purposes.
 * -------------------------------------------------------------------------------
 */
uint32_t
hashlittle(const void *key, size_t length, uint32_t initval)
{
	uint32_t a, b, c;                                      /* internal state */
	union
	{
		const void *ptr;
		size_t i;
	}
	u;                                        /* needed for Mac Powerbook G4 */

	/* Set up the internal state */
	a = b = c = 0xdeadbeef + ((uint32_t) length) + initval;

	u.ptr = key;
	if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0))
	{
		const uint32_t *k = (const uint32_t *) key;    /* read 32-bit chunks */

#ifdef VALGRIND
		const uint8_t *k8;
#endif

		/*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
		while (length > 12)
		{
			a += k[0];
			b += k[1];
			c += k[2];
			mix(a, b, c);
			length -= 12;
			k += 3;
		}

		/*----------------------------- handle the last (probably partial) block */

		/*
		 * "k[2]&0xffffff" actually reads beyond the end of the string, but
		 * then masks off the part it's not allowed to read.  Because the
		 * string is aligned, the masked-off tail is in the same word as the
		 * rest of the string.  Every machine with memory protection I've seen
		 * does it on word boundaries, so is OK with this.  But VALGRIND will
		 * still catch it and complain.  The masking trick does make the hash
		 * noticably faster for short strings (like English words).
		 */
#ifndef VALGRIND

		switch (length)
		{
			case 12:
			{
				c += k[2];
				b += k[1];
				a += k[0];
				break;
			}

			case 11:
			{
				c += k[2] & 0xffffff;
				b += k[1];
				a += k[0];
				break;
			}

			case 10:
			{
				c += k[2] & 0xffff;
				b += k[1];
				a += k[0];
				break;
			}

			case 9:
			{
				c += k[2] & 0xff;
				b += k[1];
				a += k[0];
				break;
			}

			case 8:
			{
				b += k[1];
				a += k[0];
				break;
			}

			case 7:
			{
				b += k[1] & 0xffffff;
				a += k[0];
				break;
			}

			case 6:
			{
				b += k[1] & 0xffff;
				a += k[0];
				break;
			}

			case 5:
			{
				b += k[1] & 0xff;
				a += k[0];
				break;
			}

			case 4:
			{
				a += k[0];
				break;
			}

			case 3:
			{
				a += k[0] & 0xffffff;
				break;
			}

			case 2:
			{
				a += k[0] & 0xffff;
				break;
			}

			case 1:
			{
				a += k[0] & 0xff;
				break;
			}

			case 0:
				return c;           /* zero length strings require no mixing */
		}

#else /* make valgrind happy */

		k8 = (const uint8_t *) k;
		switch (length)
		{
			case 12:
			{
				c += k[2];
				b += k[1];
				a += k[0];
				break;
			}

			case 11:
			{
				c += ((uint32_t) k8[10]) << 16; /* fall through */
			}

			case 10:
			{
				c += ((uint32_t) k8[9]) << 8; /* fall through */
			}

			case 9:
			{
				c += k8[8];              /* fall through */
			}

			case 8:
			{
				b += k[1];
				a += k[0];
				break;
			}

			case 7:
			{
				b += ((uint32_t) k8[6]) << 16; /* fall through */
			}

			case 6:
			{
				b += ((uint32_t) k8[5]) << 8; /* fall through */
			}

			case 5:
			{
				b += k8[4];              /* fall through */
			}

			case 4:
			{
				a += k[0];
				break;
			}

			case 3:
			{
				a += ((uint32_t) k8[2]) << 16; /* fall through */
			}

			case 2:
			{
				a += ((uint32_t) k8[1]) << 8; /* fall through */
			}

			case 1:
			{
				a += k8[0];
				break;
			}

			case 0:
				return c;
		}

#endif /* !valgrind */
	}
	else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0))
	{
		const uint16_t *k = (const uint16_t *) key;    /* read 16-bit chunks */
		const uint8_t *k8;

		/*--------------- all but last block: aligned reads and different mixing */
		while (length > 12)
		{
			a += k[0] + (((uint32_t) k[1]) << 16);
			b += k[2] + (((uint32_t) k[3]) << 16);
			c += k[4] + (((uint32_t) k[5]) << 16);
			mix(a, b, c);
			length -= 12;
			k += 6;
		}

		/*----------------------------- handle the last (probably partial) block */
		k8 = (const uint8_t *) k;
		switch (length)
		{
			case 12:
			{
				c += k[4] + (((uint32_t) k[5]) << 16);
				b += k[2] + (((uint32_t) k[3]) << 16);
				a += k[0] + (((uint32_t) k[1]) << 16);
				break;
			}

			case 11:
			{
				c += ((uint32_t) k8[10]) << 16; /* fall through */
			}

			case 10:
			{
				c += k[4];
				b += k[2] + (((uint32_t) k[3]) << 16);
				a += k[0] + (((uint32_t) k[1]) << 16);
				break;
			}

			case 9:
			{
				c += k8[8];                 /* fall through */
			}

			case 8:
			{
				b += k[2] + (((uint32_t) k[3]) << 16);
				a += k[0] + (((uint32_t) k[1]) << 16);
				break;
			}

			case 7:
			{
				b += ((uint32_t) k8[6]) << 16; /* fall through */
			}

			case 6:
			{
				b += k[2];
				a += k[0] + (((uint32_t) k[1]) << 16);
				break;
			}

			case 5:
			{
				b += k8[4];                 /* fall through */
			}

			case 4:
			{
				a += k[0] + (((uint32_t) k[1]) << 16);
				break;
			}

			case 3:
			{
				a += ((uint32_t) k8[2]) << 16; /* fall through */
			}

			case 2:
			{
				a += k[0];
				break;
			}

			case 1:
			{
				a += k8[0];
				break;
			}

			case 0:
				return c;                  /* zero length requires no mixing */
		}
	}
	else                          /* need to read the key one byte at a time */
	{
		const uint8_t *k = (const uint8_t *) key;

		/*--------------- all but the last block: affect some 32 bits of (a,b,c) */
		while (length > 12)
		{
			a += k[0];
			a += ((uint32_t) k[1]) << 8;
			a += ((uint32_t) k[2]) << 16;
			a += ((uint32_t) k[3]) << 24;
			b += k[4];
			b += ((uint32_t) k[5]) << 8;
			b += ((uint32_t) k[6]) << 16;
			b += ((uint32_t) k[7]) << 24;
			c += k[8];
			c += ((uint32_t) k[9]) << 8;
			c += ((uint32_t) k[10]) << 16;
			c += ((uint32_t) k[11]) << 24;
			mix(a, b, c);
			length -= 12;
			k += 12;
		}

		/*-------------------------------- last block: affect all 32 bits of (c) */
		switch (length)              /* all the case statements fall through */
		{
			case 12:
			{
				c += ((uint32_t) k[11]) << 24;
			}

			case 11:
			{
				c += ((uint32_t) k[10]) << 16;
			}

			case 10:
			{
				c += ((uint32_t) k[9]) << 8;
			}

			case 9:
			{
				c += k[8];
			}

			case 8:
			{
				b += ((uint32_t) k[7]) << 24;
			}

			case 7:
			{
				b += ((uint32_t) k[6]) << 16;
			}

			case 6:
			{
				b += ((uint32_t) k[5]) << 8;
			}

			case 5:
			{
				b += k[4];
			}

			case 4:
			{
				a += ((uint32_t) k[3]) << 24;
			}

			case 3:
			{
				a += ((uint32_t) k[2]) << 16;
			}

			case 2:
			{
				a += ((uint32_t) k[1]) << 8;
			}

			case 1:
			{
				a += k[0];
				break;
			}

			case 0:
				return c;
		}
	}

	final(a, b, c);
	return c;
}


/*
 * hashlittle2: return 2 32-bit hash values
 *
 * This is identical to hashlittle(), except it returns two 32-bit hash
 * values instead of just one.  This is good enough for hash table
 * lookup with 2^^64 buckets, or if you want a second hash if you're not
 * happy with the first, or if you want a probably-unique 64-bit ID for
 * the key.  *pc is better mixed than *pb, so use *pc first.  If you want
 * a 64-bit value do something like "*pc + (((uint64_t)*pb)<<32)".
 */
void
hashlittle2(const void *key, /* the key to hash */
			size_t length, /* length of the key */
			uint32_t *pc, /* IN: primary initval, OUT: primary hash */
			uint32_t *pb) /* IN: secondary initval, OUT: secondary hash */
{
	uint32_t a, b, c;                                      /* internal state */
	union
	{
		const void *ptr;
		size_t i;
	}
	u;                                        /* needed for Mac Powerbook G4 */

	/* Set up the internal state */
	a = b = c = 0xdeadbeef + ((uint32_t) length) + *pc;
	c += *pb;

	u.ptr = key;
	if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0))
	{
		const uint32_t *k = (const uint32_t *) key;    /* read 32-bit chunks */

#ifdef VALGRIND
		const uint8_t *k8;
#endif

		/*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
		while (length > 12)
		{
			a += k[0];
			b += k[1];
			c += k[2];
			mix(a, b, c);
			length -= 12;
			k += 3;
		}

		/*----------------------------- handle the last (probably partial) block */

		/*
		 * "k[2]&0xffffff" actually reads beyond the end of the string, but
		 * then masks off the part it's not allowed to read.  Because the
		 * string is aligned, the masked-off tail is in the same word as the
		 * rest of the string.  Every machine with memory protection I've seen
		 * does it on word boundaries, so is OK with this.  But VALGRIND will
		 * still catch it and complain.  The masking trick does make the hash
		 * noticably faster for short strings (like English words).
		 */
#ifndef VALGRIND

		switch (length)
		{
			case 12:
			{
				c += k[2];
				b += k[1];
				a += k[0];
				break;
			}

			case 11:
			{
				c += k[2] & 0xffffff;
				b += k[1];
				a += k[0];
				break;
			}

			case 10:
			{
				c += k[2] & 0xffff;
				b += k[1];
				a += k[0];
				break;
			}

			case 9:
			{
				c += k[2] & 0xff;
				b += k[1];
				a += k[0];
				break;
			}

			case 8:
			{
				b += k[1];
				a += k[0];
				break;
			}

			case 7:
			{
				b += k[1] & 0xffffff;
				a += k[0];
				break;
			}

			case 6:
			{
				b += k[1] & 0xffff;
				a += k[0];
				break;
			}

			case 5:
			{
				b += k[1] & 0xff;
				a += k[0];
				break;
			}

			case 4:
			{
				a += k[0];
				break;
			}

			case 3:
			{
				a += k[0] & 0xffffff;
				break;
			}

			case 2:
			{
				a += k[0] & 0xffff;
				break;
			}

			case 1:
			{
				a += k[0] & 0xff;
				break;
			}

			case 0:
				*pc = c;
				*pb = b;
				return;             /* zero length strings require no mixing */
		}

#else /* make valgrind happy */

		k8 = (const uint8_t *) k;
		switch (length)
		{
			case 12:
			{
				c += k[2];
				b += k[1];
				a += k[0];
				break;
			}

			case 11:
			{
				c += ((uint32_t) k8[10]) << 16; /* fall through */
			}

			case 10:
			{
				c += ((uint32_t) k8[9]) << 8; /* fall through */
			}

			case 9:
			{
				c += k8[8];              /* fall through */
			}

			case 8:
			{
				b += k[1];
				a += k[0];
				break;
			}

			case 7:
			{
				b += ((uint32_t) k8[6]) << 16; /* fall through */
			}

			case 6:
			{
				b += ((uint32_t) k8[5]) << 8; /* fall through */
			}

			case 5:
			{
				b += k8[4];              /* fall through */
			}

			case 4:
			{
				a += k[0];
				break;
			}

			case 3:
			{
				a += ((uint32_t) k8[2]) << 16; /* fall through */
			}

			case 2:
			{
				a += ((uint32_t) k8[1]) << 8; /* fall through */
			}

			case 1:
			{
				a += k8[0];
				break;
			}

			case 0:
				*pc = c;
				*pb = b;
				return;             /* zero length strings require no mixing */
		}

#endif /* !valgrind */
	}
	else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0))
	{
		const uint16_t *k = (const uint16_t *) key;    /* read 16-bit chunks */
		const uint8_t *k8;

		/*--------------- all but last block: aligned reads and different mixing */
		while (length > 12)
		{
			a += k[0] + (((uint32_t) k[1]) << 16);
			b += k[2] + (((uint32_t) k[3]) << 16);
			c += k[4] + (((uint32_t) k[5]) << 16);
			mix(a, b, c);
			length -= 12;
			k += 6;
		}

		/*----------------------------- handle the last (probably partial) block */
		k8 = (const uint8_t *) k;
		switch (length)
		{
			case 12:
			{
				c += k[4] + (((uint32_t) k[5]) << 16);
				b += k[2] + (((uint32_t) k[3]) << 16);
				a += k[0] + (((uint32_t) k[1]) << 16);
				break;
			}

			case 11:
			{
				c += ((uint32_t) k8[10]) << 16; /* fall through */
			}

			case 10:
			{
				c += k[4];
				b += k[2] + (((uint32_t) k[3]) << 16);
				a += k[0] + (((uint32_t) k[1]) << 16);
				break;
			}

			case 9:
			{
				c += k8[8];                 /* fall through */
			}

			case 8:
			{
				b += k[2] + (((uint32_t) k[3]) << 16);
				a += k[0] + (((uint32_t) k[1]) << 16);
				break;
			}

			case 7:
			{
				b += ((uint32_t) k8[6]) << 16; /* fall through */
			}

			case 6:
			{
				b += k[2];
				a += k[0] + (((uint32_t) k[1]) << 16);
				break;
			}

			case 5:
			{
				b += k8[4];                 /* fall through */
			}

			case 4:
			{
				a += k[0] + (((uint32_t) k[1]) << 16);
				break;
			}

			case 3:
			{
				a += ((uint32_t) k8[2]) << 16; /* fall through */
			}

			case 2:
			{
				a += k[0];
				break;
			}

			case 1:
			{
				a += k8[0];
				break;
			}

			case 0:
				*pc = c;
				*pb = b;
				return;             /* zero length strings require no mixing */
		}
	}
	else                          /* need to read the key one byte at a time */
	{
		const uint8_t *k = (const uint8_t *) key;

		/*--------------- all but the last block: affect some 32 bits of (a,b,c) */
		while (length > 12)
		{
			a += k[0];
			a += ((uint32_t) k[1]) << 8;
			a += ((uint32_t) k[2]) << 16;
			a += ((uint32_t) k[3]) << 24;
			b += k[4];
			b += ((uint32_t) k[5]) << 8;
			b += ((uint32_t) k[6]) << 16;
			b += ((uint32_t) k[7]) << 24;
			c += k[8];
			c += ((uint32_t) k[9]) << 8;
			c += ((uint32_t) k[10]) << 16;
			c += ((uint32_t) k[11]) << 24;
			mix(a, b, c);
			length -= 12;
			k += 12;
		}

		/*-------------------------------- last block: affect all 32 bits of (c) */
		switch (length)              /* all the case statements fall through */
		{
			case 12:
			{
				c += ((uint32_t) k[11]) << 24;
			}

			case 11:
			{
				c += ((uint32_t) k[10]) << 16;
			}

			case 10:
			{
				c += ((uint32_t) k[9]) << 8;
			}

			case 9:
			{
				c += k[8];
			}

			case 8:
			{
				b += ((uint32_t) k[7]) << 24;
			}

			case 7:
			{
				b += ((uint32_t) k[6]) << 16;
			}

			case 6:
			{
				b += ((uint32_t) k[5]) << 8;
			}

			case 5:
			{
				b += k[4];
			}

			case 4:
			{
				a += ((uint32_t) k[3]) << 24;
			}

			case 3:
			{
				a += ((uint32_t) k[2]) << 16;
			}

			case 2:
			{
				a += ((uint32_t) k[1]) << 8;
			}

			case 1:
			{
				a += k[0];
				break;
			}

			case 0:
				*pc = c;
				*pb = b;
				return;             /* zero length strings require no mixing */
		}
	}

	final(a, b, c);
	*pc = c;
	*pb = b;
}


/*
 * hashbig():
 * This is the same as hashword() on big-endian machines.  It is different
 * from hashlittle() on all machines.  hashbig() takes advantage of
 * big-endian byte ordering.
 */
uint32_t
hashbig(const void *key, size_t length, uint32_t initval)
{
	uint32_t a, b, c;
	union
	{
		const void *ptr;
		size_t i;
	}
	u;                                    /* to cast key to (size_t) happily */

	/* Set up the internal state */
	a = b = c = 0xdeadbeef + ((uint32_t) length) + initval;

	u.ptr = key;
	if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0))
	{
		const uint32_t *k = (const uint32_t *) key;    /* read 32-bit chunks */

#ifdef VALGRIND
		const uint8_t *k8;
#endif

		/*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
		while (length > 12)
		{
			a += k[0];
			b += k[1];
			c += k[2];
			mix(a, b, c);
			length -= 12;
			k += 3;
		}

		/*----------------------------- handle the last (probably partial) block */

		/*
		 * "k[2]<<8" actually reads beyond the end of the string, but
		 * then shifts out the part it's not allowed to read.  Because the
		 * string is aligned, the illegal read is in the same word as the
		 * rest of the string.  Every machine with memory protection I've seen
		 * does it on word boundaries, so is OK with this.  But VALGRIND will
		 * still catch it and complain.  The masking trick does make the hash
		 * noticably faster for short strings (like English words).
		 */
#ifndef VALGRIND

		switch (length)
		{
			case 12:
			{
				c += k[2];
				b += k[1];
				a += k[0];
				break;
			}

			case 11:
			{
				c += k[2] & 0xffffff00;
				b += k[1];
				a += k[0];
				break;
			}

			case 10:
			{
				c += k[2] & 0xffff0000;
				b += k[1];
				a += k[0];
				break;
			}

			case 9:
			{
				c += k[2] & 0xff000000;
				b += k[1];
				a += k[0];
				break;
			}

			case 8:
			{
				b += k[1];
				a += k[0];
				break;
			}

			case 7:
			{
				b += k[1] & 0xffffff00;
				a += k[0];
				break;
			}

			case 6:
			{
				b += k[1] & 0xffff0000;
				a += k[0];
				break;
			}

			case 5:
			{
				b += k[1] & 0xff000000;
				a += k[0];
				break;
			}

			case 4:
			{
				a += k[0];
				break;
			}

			case 3:
			{
				a += k[0] & 0xffffff00;
				break;
			}

			case 2:
			{
				a += k[0] & 0xffff0000;
				break;
			}

			case 1:
			{
				a += k[0] & 0xff000000;
				break;
			}

			case 0:
				return c;           /* zero length strings require no mixing */
		}

#else  /* make valgrind happy */

		k8 = (const uint8_t *) k;
		switch (length)              /* all the case statements fall through */
		{
			case 12:
			{
				c += k[2];
				b += k[1];
				a += k[0];
				break;
			}

			case 11:
			{
				c += ((uint32_t) k8[10]) << 8; /* fall through */
			}

			case 10:
			{
				c += ((uint32_t) k8[9]) << 16; /* fall through */
			}

			case 9:
			{
				c += ((uint32_t) k8[8]) << 24; /* fall through */
			}

			case 8:
			{
				b += k[1];
				a += k[0];
				break;
			}

			case 7:
			{
				b += ((uint32_t) k8[6]) << 8; /* fall through */
			}

			case 6:
			{
				b += ((uint32_t) k8[5]) << 16; /* fall through */
			}

			case 5:
			{
				b += ((uint32_t) k8[4]) << 24; /* fall through */
			}

			case 4:
			{
				a += k[0];
				break;
			}

			case 3:
			{
				a += ((uint32_t) k8[2]) << 8; /* fall through */
			}

			case 2:
			{
				a += ((uint32_t) k8[1]) << 16; /* fall through */
			}

			case 1:
			{
				a += ((uint32_t) k8[0]) << 24;
				break;
			}

			case 0:
				return c;
		}

#endif /* !VALGRIND */
	}
	else                          /* need to read the key one byte at a time */
	{
		const uint8_t *k = (const uint8_t *) key;

		/*--------------- all but the last block: affect some 32 bits of (a,b,c) */
		while (length > 12)
		{
			a += ((uint32_t) k[0]) << 24;
			a += ((uint32_t) k[1]) << 16;
			a += ((uint32_t) k[2]) << 8;
			a += ((uint32_t) k[3]);
			b += ((uint32_t) k[4]) << 24;
			b += ((uint32_t) k[5]) << 16;
			b += ((uint32_t) k[6]) << 8;
			b += ((uint32_t) k[7]);
			c += ((uint32_t) k[8]) << 24;
			c += ((uint32_t) k[9]) << 16;
			c += ((uint32_t) k[10]) << 8;
			c += ((uint32_t) k[11]);
			mix(a, b, c);
			length -= 12;
			k += 12;
		}

		/*-------------------------------- last block: affect all 32 bits of (c) */
		switch (length)              /* all the case statements fall through */
		{
			case 12:
			{
				c += k[11];
			}

			case 11:
			{
				c += ((uint32_t) k[10]) << 8;
			}

			case 10:
			{
				c += ((uint32_t) k[9]) << 16;
			}

			case 9:
			{
				c += ((uint32_t) k[8]) << 24;
			}

			case 8:
			{
				b += k[7];
			}

			case 7:
			{
				b += ((uint32_t) k[6]) << 8;
			}

			case 6:
			{
				b += ((uint32_t) k[5]) << 16;
			}

			case 5:
			{
				b += ((uint32_t) k[4]) << 24;
			}

			case 4:
			{
				a += k[3];
			}

			case 3:
			{
				a += ((uint32_t) k[2]) << 8;
			}

			case 2:
			{
				a += ((uint32_t) k[1]) << 16;
			}

			case 1:
			{
				a += ((uint32_t) k[0]) << 24;
				break;
			}

			case 0:
				return c;
		}
	}

	final(a, b, c);
	return c;
}


#ifdef SELF_TEST

/* used for timings */
void
driver1()
{
	uint8_t buf[256];
	uint32_t i;
	uint32_t h = 0;
	time_t a, z;

	time(&a);
	for (i = 0; i < 256; ++i)
	{
		buf[i] = 'x';
	}
	for (i = 0; i < 1; ++i)
	{
		h = hashlittle(&buf[0], 1, h);
	}
	time(&z);
	if (z - a > 0)
	{
		printf("time %d %.8x\n", z - a, h);
	}
}


/* check that every input bit changes every output bit half the time */
#define HASHSTATE 1
#define HASHLEN 1
#define MAXPAIR 60
#define MAXLEN 70
void
driver2()
{
	uint8_t qa[MAXLEN + 1], qb[MAXLEN + 2], *a = &qa[0], *b = &qb[1];
	uint32_t c[HASHSTATE], d[HASHSTATE], i = 0, j = 0, k, l, m = 0, z;
	uint32_t e[HASHSTATE], f[HASHSTATE], g[HASHSTATE], h[HASHSTATE];
	uint32_t x[HASHSTATE], y[HASHSTATE];
	uint32_t hlen;

	printf("No more than %d trials should ever be needed \n", MAXPAIR / 2);
	for (hlen = 0; hlen < MAXLEN; ++hlen)
	{
		z = 0;
		for (i = 0; i < hlen; ++i) /*----------------------- for each input byte, */
		{
			for (j = 0; j < 8; ++j) /*------------------------ for each input bit, */
			{
				for (m = 1; m < 8; ++m) /*------------ for serveral possible initvals, */
				{
					for (l = 0; l < HASHSTATE; ++l)
					{
						e[l] = f[l] = g[l] = h[l] = x[l] = y[l] = ~((uint32_t) 0);
					}

					/*---- check that every output bit is affected by that input bit */
					for (k = 0; k < MAXPAIR; k += 2)
					{
						uint32_t finished = 1;

						/* keys have one bit different */
						for (l = 0; l < hlen + 1; ++l)
						{
							a[l] = b[l] = (uint8_t) 0;
						}

						/* have a and b be two keys differing in only one bit */
						a[i] ^= (k << j);
						a[i] ^= (k >> (8 - j));
						c[0] = hashlittle(a, hlen, m);
						b[i] ^= ((k + 1) << j);
						b[i] ^= ((k + 1) >> (8 - j));
						d[0] = hashlittle(b, hlen, m);

						/* check every bit is 1, 0, set, and not set at least once */
						for (l = 0; l < HASHSTATE; ++l)
						{
							e[l] &= (c[l] ^ d[l]);
							f[l] &= ~(c[l] ^ d[l]);
							g[l] &= c[l];
							h[l] &= ~c[l];
							x[l] &= d[l];
							y[l] &= ~d[l];
							if (e[l] | f[l] | g[l] | h[l] | x[l] | y[l])
							{
								finished = 0;
							}
						}
						if (finished)
						{
							break;
						}
					}
					if (k > z)
					{
						z = k;
					}
					if (k == MAXPAIR)
					{
						printf("Some bit didn't change: ");
						printf("%.8x %.8x %.8x %.8x %.8x %.8x  ",
							   e[0], f[0], g[0], h[0], x[0], y[0]);
						printf("i %d j %d m %d len %d\n", i, j, m, hlen);
					}
					if (z == MAXPAIR)
					{
						goto done;
					}
				}
			}
		}
done:
		if (z < MAXPAIR)
		{
			printf("Mix success  %2d bytes  %2d initvals  ", i, m);
			printf("required  %d  trials\n", z / 2);
		}
	}
	printf("\n");
}


/* Check for reading beyond the end of the buffer and alignment problems */
void
driver3()
{
	uint8_t buf[MAXLEN + 20], *b;
	uint32_t len;
	uint8_t q[] =
		"This is the time for all good men to come to the aid of their country...";
	uint32_t h;
	uint8_t qq[] =
		"xThis is the time for all good men to come to the aid of their country...";
	uint32_t i;
	uint8_t qqq[] =
		"xxThis is the time for all good men to come to the aid of their country...";
	uint32_t j;
	uint8_t qqqq[] =
		"xxxThis is the time for all good men to come to the aid of their country...";
	uint32_t ref, x, y;
	uint8_t *p;

	printf("Endianness.  These lines should all be the same (for values filled in):\n");
	printf("%.8x                            %.8x                            %.8x\n",
		   hashword((const uint32_t *) q, (sizeof(q) - 1) / 4, 13),
		   hashword((const uint32_t *) q, (sizeof(q) - 5) / 4, 13),
		   hashword((const uint32_t *) q, (sizeof(q) - 9) / 4, 13));
	p = q;
	printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
		   hashlittle(p, sizeof(q) - 1, 13), hashlittle(p, sizeof(q) - 2, 13),
		   hashlittle(p, sizeof(q) - 3, 13), hashlittle(p, sizeof(q) - 4, 13),
		   hashlittle(p, sizeof(q) - 5, 13), hashlittle(p, sizeof(q) - 6, 13),
		   hashlittle(p, sizeof(q) - 7, 13), hashlittle(p, sizeof(q) - 8, 13),
		   hashlittle(p, sizeof(q) - 9, 13), hashlittle(p, sizeof(q) - 10, 13),
		   hashlittle(p, sizeof(q) - 11, 13), hashlittle(p, sizeof(q) - 12, 13));
	p = &qq[1];
	printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
		   hashlittle(p, sizeof(q) - 1, 13), hashlittle(p, sizeof(q) - 2, 13),
		   hashlittle(p, sizeof(q) - 3, 13), hashlittle(p, sizeof(q) - 4, 13),
		   hashlittle(p, sizeof(q) - 5, 13), hashlittle(p, sizeof(q) - 6, 13),
		   hashlittle(p, sizeof(q) - 7, 13), hashlittle(p, sizeof(q) - 8, 13),
		   hashlittle(p, sizeof(q) - 9, 13), hashlittle(p, sizeof(q) - 10, 13),
		   hashlittle(p, sizeof(q) - 11, 13), hashlittle(p, sizeof(q) - 12, 13));
	p = &qqq[2];
	printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
		   hashlittle(p, sizeof(q) - 1, 13), hashlittle(p, sizeof(q) - 2, 13),
		   hashlittle(p, sizeof(q) - 3, 13), hashlittle(p, sizeof(q) - 4, 13),
		   hashlittle(p, sizeof(q) - 5, 13), hashlittle(p, sizeof(q) - 6, 13),
		   hashlittle(p, sizeof(q) - 7, 13), hashlittle(p, sizeof(q) - 8, 13),
		   hashlittle(p, sizeof(q) - 9, 13), hashlittle(p, sizeof(q) - 10, 13),
		   hashlittle(p, sizeof(q) - 11, 13), hashlittle(p, sizeof(q) - 12, 13));
	p = &qqqq[3];
	printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
		   hashlittle(p, sizeof(q) - 1, 13), hashlittle(p, sizeof(q) - 2, 13),
		   hashlittle(p, sizeof(q) - 3, 13), hashlittle(p, sizeof(q) - 4, 13),
		   hashlittle(p, sizeof(q) - 5, 13), hashlittle(p, sizeof(q) - 6, 13),
		   hashlittle(p, sizeof(q) - 7, 13), hashlittle(p, sizeof(q) - 8, 13),
		   hashlittle(p, sizeof(q) - 9, 13), hashlittle(p, sizeof(q) - 10, 13),
		   hashlittle(p, sizeof(q) - 11, 13), hashlittle(p, sizeof(q) - 12, 13));
	printf("\n");

	/* check that hashlittle2 and hashlittle produce the same results */
	i = 47;
	j = 0;
	hashlittle2(q, sizeof(q), &i, &j);
	if (hashlittle(q, sizeof(q), 47) != i)
	{
		printf("hashlittle2 and hashlittle mismatch\n");
	}

	/* check that hashword2 and hashword produce the same results */
	len = 0xdeadbeef;
	i = 47, j = 0;
	hashword2(&len, 1, &i, &j);
	if (hashword(&len, 1, 47) != i)
	{
		printf("hashword2 and hashword mismatch %x %x\n",
			   i, hashword(&len, 1, 47));
	}

	/* check hashlittle doesn't read before or after the ends of the string */
	for (h = 0, b = buf + 1; h < 8; ++h, ++b)
	{
		for (i = 0; i < MAXLEN; ++i)
		{
			len = i;
			for (j = 0; j < i; ++j)
			{
				*(b + j) = 0;
			}

			/* these should all be equal */
			ref = hashlittle(b, len, (uint32_t) 1);
			*(b + i) = (uint8_t) ~0;
			*(b - 1) = (uint8_t) ~0;
			x = hashlittle(b, len, (uint32_t) 1);
			y = hashlittle(b, len, (uint32_t) 1);
			if ((ref != x) || (ref != y))
			{
				printf("alignment error: %.8x %.8x %.8x %d %d\n", ref, x, y,
					   h, i);
			}
		}
	}
}


/* check for problems with nulls */
void
driver4()
{
	uint8_t buf[1];
	uint32_t h, i, state[HASHSTATE];


	buf[0] = ~0;
	for (i = 0; i < HASHSTATE; ++i)
	{
		state[i] = 1;
	}
	printf("These should all be different\n");
	for (i = 0, h = 0; i < 8; ++i)
	{
		h = hashlittle(buf, 0, h);
		printf("%2ld  0-byte strings, hash is  %.8x\n", i, h);
	}
}


void
driver5()
{
	uint32_t b, c;
	b = 0, c = 0, hashlittle2("", 0, &c, &b);
	printf("hash is %.8lx %.8lx\n", c, b); /* deadbeef deadbeef */
	b = 0xdeadbeef, c = 0, hashlittle2("", 0, &c, &b);
	printf("hash is %.8lx %.8lx\n", c, b); /* bd5b7dde deadbeef */
	b = 0xdeadbeef, c = 0xdeadbeef, hashlittle2("", 0, &c, &b);
	printf("hash is %.8lx %.8lx\n", c, b); /* 9c093ccd bd5b7dde */
	b = 0, c = 0, hashlittle2("Four score and seven years ago", 30, &c, &b);
	printf("hash is %.8lx %.8lx\n", c, b); /* 17770551 ce7226e6 */
	b = 1, c = 0, hashlittle2("Four score and seven years ago", 30, &c, &b);
	printf("hash is %.8lx %.8lx\n", c, b); /* e3607cae bd371de4 */
	b = 0, c = 1, hashlittle2("Four score and seven years ago", 30, &c, &b);
	printf("hash is %.8lx %.8lx\n", c, b); /* cd628161 6cbea4b3 */
	c = hashlittle("Four score and seven years ago", 30, 0);
	printf("hash is %.8lx\n", c); /* 17770551 */
	c = hashlittle("Four score and seven years ago", 30, 1);
	printf("hash is %.8lx\n", c); /* cd628161 */
}


int
main()
{
	driver1(); /* test that the key is hashed: used for timings */
	driver2(); /* test that whole key is hashed thoroughly */
	driver3(); /* test that nothing but the key is hashed */
	driver4(); /* test hashing multiple buffers (all buffers are null) */
	driver5(); /* test the hash against known vectors */
	return 0;
}


#endif  /* SELF_TEST */
