hash: cleanup the Jenkins hash source to better match our code

Style improvements as well as a wrapper function to select the "best"
hash for a given situation.  Some unused functions were also removed.

Signed-off-by: Paul Moore <pmoore@redhat.com>

1 files changed, 240 insertions, 565 deletions

diff --git a/src/hash.c b/src/hash.c
index 5b55679..cb52b3b 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -1,116 +1,95 @@
+/**
+ * Seccomp Library hash code
+ *
+ * Release under the Public Domain
+ * Author: Bob Jenkins <bob_jenkins@burtleburtle.net>
+ */
+
 /*
--------------------------------------------------------------------------------
-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.
--------------------------------------------------------------------------------
-*/
-
-#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
+ * lookup3.c, by Bob Jenkins, May 2006, Public Domain.
+ *
+ * These are functions for producing 32-bit hashes for hash table lookup.
+ * jhash_word(), jhash_le(), jhash_be(), 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 jhash_le().  jhash_le() and jhash_be() hash byte
+ * arrays.  jhash_le() is is faster than jhash_be() on little-endian machines.
+ * Intel and AMD are little-endian machines.
+ *
+ * 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 jhash_word().  If you have a byte array (like
+ * a character string), use jhash_le().  If you have several byte arrays, or
+ * a mix of things, see the comments above jhash_le().
+ *
+ * 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.
+ */
+
+#include <stdint.h>
 
+#include "arch.h"
 #include "hash.h"
-#define hashlittle jhash
 
-/*
- * 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))))
+#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.
--------------------------------------------------------------------------------
-*/
+/**
+ * Mix 3 32-bit values reversibly
+ * @param a 32-bit value
+ * @param b 32-bit value
+ * @param c 32-bit value
+ *
+ * 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; \
@@ -121,31 +100,31 @@ rotates.
 		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
--------------------------------------------------------------------------------
-*/
+/**
+ * Final mixing of 3 32-bit values (a,b,c) into c
+ * @param a 32-bit value
+ * @param b 32-bit value
+ * @param c 32-bit value
+ *
+ * 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); \
@@ -157,30 +136,31 @@ and these came close:
 		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 */
+/**
+ * Hash an array of 32-bit values
+ * @param k the key, an array of uint32_t values
+ * @param length the number of array elements
+ * @param initval the previous hash, or an arbitrary value
+ *
+ * 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 jhash_word() is identical to jhash_le() on little-endian
+ * machines, and identical to jhash_be() on big-endian machines, except that
+ * the length has to be measured in uint32_ts rather than in bytes.  jhash_le()
+ * is more complicated than jhash_word() only because jhash_le() has to dance
+ * around fitting the key bytes into registers.
+ *
+ */
+static uint32_t jhash_word(const uint32_t *k, size_t length, uint32_t initval)
 {
 	uint32_t a, b, c;
 
-	/* Set up the internal state */
+	/* set up the internal state */
 	a = b = c = 0xdeadbeef + (((uint32_t)length) << 2) + initval;
 
-	/*-------------------------------------------- handle most of the key */
+	/* handle most of the key */
 	while (length > 3) {
 		a += k[0];
 		b += k[1];
@@ -190,8 +170,8 @@ uint32_t hashword(
 		k += 3;
 	}
 
-	/*-------------------------------------- handle the last 3 uint32_t's */
-	switch(length) {              /* all the case statements fall through */
+	/* handle the last 3 uint32_t's */
+	switch(length) {
 	case 3 :
 		c += k[2];
 	case 2 :
@@ -199,103 +179,51 @@ uint32_t hashword(
 	case 1 :
 		a += k[0];
 		final(a, b, c);
-	case 0:     /* case 0: nothing left to add */
+	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 */
+/**
+ * Hash a variable-length key into a 32-bit value
+ * @param k the key (the unaligned variable-length array of bytes)
+ * @param length the length of the key, counting by bytes
+ * @param 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 = jhash_le( k[i], len[i], h);
+ *
+ */
+static uint32_t jhash_le(const void *key, size_t length, uint32_t initval)
 {
 	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 */
+	/* 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 32b chunks */
+	if ((arch_def_native->endian == ARCH_ENDIAN_LITTLE) &&
+	    ((u.i & 0x3) == 0)) {
+		/* read 32-bit chunks */
+		const uint32_t *k = (const uint32_t *)key;
 
-		/* all but last block: aligned reads and affect 32-bits
-		 * of (a,b,c) */
 		while (length > 12) {
 			a += k[0];
 			b += k[1];
@@ -305,17 +233,14 @@ uint32_t hashlittle( const void *key, size_t length, uint32_t initval)
 			k += 3;
 		}
 
-		/*------------------ handle the last (probably partial) block */
-		/*
-		 * "k[2]&0xffffff" actually reads beyond the end of the string,
+		/* "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).
-		 */
+		 * faster for short strings (like English words). */
 #ifndef VALGRIND
 
 		switch(length) {
@@ -368,7 +293,8 @@ uint32_t hashlittle( const void *key, size_t length, uint32_t initval)
 			a += k[0] & 0xff;
 			break;
 		case 0 :
-			return c;    /* zero length strings require no mixing */
+			/* zero length strings require no mixing */
+			return c;
 		}
 
 #else /* make valgrind happy */
@@ -381,28 +307,28 @@ uint32_t hashlittle( const void *key, size_t length, uint32_t initval)
 			a += k[0];
 			break;
 		case 11:
-			c += ((uint32_t)k8[10]) << 16; /* fall through */
+			c += ((uint32_t)k8[10]) << 16;
 		case 10:
-			c += ((uint32_t)k8[9]) << 8; /* fall through */
+			c += ((uint32_t)k8[9]) << 8;
 		case 9 :
-			c += k8[8];                 /* fall through */
+			c += k8[8];
 		case 8 :
 			b += k[1];
 			a += k[0];
 			break;
 		case 7 :
-			b += ((uint32_t)k8[6]) << 16; /* fall through */
+			b += ((uint32_t)k8[6]) << 16;
 		case 6 :
-			b += ((uint32_t)k8[5]) << 8; /* fall through */
+			b += ((uint32_t)k8[5]) << 8;
 		case 5 :
-			b += k8[4];                 /* fall through */
+			b += k8[4];
 		case 4 :
 			a += k[0];
 			break;
 		case 3 :
-			a += ((uint32_t)k8[2]) << 16; /* fall through */
+			a += ((uint32_t)k8[2]) << 16;
 		case 2 :
-			a += ((uint32_t)k8[1]) << 8; /* fall through */
+			a += ((uint32_t)k8[1]) << 8;
 		case 1 :
 			a += k8[0];
 			break;
@@ -412,11 +338,12 @@ uint32_t hashlittle( const void *key, size_t length, uint32_t initval)
 
 #endif /* !valgrind */
 
-	} else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
-		const uint16_t *k = (const uint16_t *)key; /* read 16b chunks */
+	} else if ((arch_def_native->endian == ARCH_ENDIAN_LITTLE) &&
+		   ((u.i & 0x1) == 0)) {
+		/* read 16-bit chunks */
+		const uint16_t *k = (const uint16_t *)key;
 		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);
@@ -426,7 +353,6 @@ uint32_t hashlittle( const void *key, size_t length, uint32_t initval)
 			k += 6;
 		}
 
-		/*------------------ handle the last (probably partial) block */
 		k8 = (const uint8_t *)k;
 		switch(length) {
 		case 12:
@@ -435,31 +361,31 @@ uint32_t hashlittle( const void *key, size_t length, uint32_t initval)
 			a += k[0] + (((uint32_t)k[1]) << 16);
 			break;
 		case 11:
-			c += ((uint32_t)k8[10]) << 16; /* fall through */
+			c += ((uint32_t)k8[10]) << 16;
 		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 */
+			c += k8[8];
 		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 */
+			b += ((uint32_t)k8[6]) << 16;
 		case 6 :
 			b += k[2];
 			a += k[0] + (((uint32_t)k[1]) << 16);
 			break;
 		case 5 :
-			b += k8[4];                    /* fall through */
+			b += k8[4];
 		case 4 :
 			a += k[0] + (((uint32_t)k[1]) << 16);
 			break;
 		case 3 :
-			a += ((uint32_t)k8[2]) << 16;  /* fall through */
+			a += ((uint32_t)k8[2]) << 16;
 		case 2 :
 			a += k[0];
 			break;
@@ -467,13 +393,14 @@ uint32_t hashlittle( const void *key, size_t length, uint32_t initval)
 			a += k8[0];
 			break;
 		case 0 :
-			return c;           /* zero length requires no mixing */
+			/* zero length requires no mixing */
+			return c;
 		}
 
-	} else {                   /* need to read the key one byte at a time */
+	} 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;
@@ -492,8 +419,7 @@ uint32_t hashlittle( const void *key, size_t length, uint32_t initval)
 			k += 12;
 		}
 
-		/*--------------------- last block: affect all 32 bits of (c) */
-		switch(length) {      /* all the case statements fall through */
+		switch(length) {
 		case 12:
 			c += ((uint32_t)k[11]) << 24;
 		case 11:
@@ -528,286 +454,18 @@ uint32_t hashlittle( const void *key, size_t length, uint32_t initval)
 	return c;
 }
 
-/*
- * hashlittle2: return 2 32-bit hash values
+/**
+ * Hash a variable-length key into a 32-bit value
+ * @param k the key (the unaligned variable-length array of bytes)
+ * @param length the length of the key, counting by bytes
+ * @param initval can be any 4-byte value
+ *
+ * This is the same as jhash_word() on big-endian machines.  It is different
+ * from jhash_le() on all machines.  jhash_be() takes advantage of big-endian
+ * byte ordering.
  *
- * 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 32b chunks */
-
-		/* 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 16b 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)
+static uint32_t jhash_be( const void *key, size_t length, uint32_t initval)
 {
 	uint32_t a, b, c;
 	union {
@@ -815,15 +473,15 @@ uint32_t hashbig( const void *key, size_t length, uint32_t initval)
 		size_t i;
 	} u; /* to cast key to (size_t) happily */
 
-	/* Set up the internal state */
+	/* 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 32b chunks */
+	if ((arch_def_native->endian == ARCH_ENDIAN_BIG) &&
+	    ((u.i & 0x3) == 0)) {
+		/* read 32-bit chunks */
+		const uint32_t *k = (const uint32_t *)key;
 
-		/* all but last block: aligned reads and affect 32 bits
-		 * of (a,b,c) */
 		while (length > 12) {
 			a += k[0];
 			b += k[1];
@@ -833,17 +491,14 @@ uint32_t hashbig( const void *key, size_t length, uint32_t initval)
 			k += 3;
 		}
 
-		/*------------------ handle the last (probably partial) block */
-		/*
-		 * "k[2]<<8" actually reads beyond the end of the string, but
+		/* "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).
-		 */
+		 * short strings (like English words). */
 #ifndef VALGRIND
 
 		switch(length) {
@@ -896,41 +551,42 @@ uint32_t hashbig( const void *key, size_t length, uint32_t initval)
 			a += k[0] & 0xff000000;
 			break;
 		case 0 :
-			return c;    /* zero length strings require no mixing */
+			/* zero length strings require no mixing */
+			return c;
 		}
 
 #else  /* make valgrind happy */
 
 		k8 = (const uint8_t *)k;
-		switch(length) {      /* all the case statements fall through */
+		switch(length) {
 		case 12:
 			c += k[2];
 			b += k[1];
 			a += k[0];
 			break;
 		case 11:
-			c += ((uint32_t)k8[10]) << 8; /* fall through */
+			c += ((uint32_t)k8[10]) << 8;
 		case 10:
-			c += ((uint32_t)k8[9]) << 16; /* fall through */
+			c += ((uint32_t)k8[9]) << 16;
 		case 9 :
-			c += ((uint32_t)k8[8]) << 24; /* fall through */
+			c += ((uint32_t)k8[8]) << 24;
 		case 8 :
 			b += k[1];
 			a += k[0];
 			break;
 		case 7 :
-			b += ((uint32_t)k8[6]) << 8; /* fall through */
+			b += ((uint32_t)k8[6]) << 8;
 		case 6 :
-			b += ((uint32_t)k8[5]) << 16; /* fall through */
+			b += ((uint32_t)k8[5]) << 16;
 		case 5 :
-			b += ((uint32_t)k8[4]) << 24; /* fall through */
+			b += ((uint32_t)k8[4]) << 24;
 		case 4 :
 			a += k[0];
 			break;
 		case 3 :
-			a += ((uint32_t)k8[2]) << 8; /* fall through */
+			a += ((uint32_t)k8[2]) << 8;
 		case 2 :
-			a += ((uint32_t)k8[1]) << 16; /* fall through */
+			a += ((uint32_t)k8[1]) << 16;
 		case 1 :
 			a += ((uint32_t)k8[0]) << 24;
 			break;
@@ -940,10 +596,10 @@ uint32_t hashbig( const void *key, size_t length, uint32_t initval)
 
 #endif /* !VALGRIND */
 
-	} else {                   /* need to read the key one byte at a time */
+	} 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;
@@ -962,8 +618,7 @@ uint32_t hashbig( const void *key, size_t length, uint32_t initval)
 			k += 12;
 		}
 
-		/*--------------------- last block: affect all 32 bits of (c) */
-		switch(length) {      /* all the case statements fall through */
+		switch(length) {
 		case 12:
 			c += k[11];
 		case 11:
@@ -997,3 +652,23 @@ uint32_t hashbig( const void *key, size_t length, uint32_t initval)
 	final(a, b, c);
 	return c;
 }
+
+/**
+ * Hash a variable-length key into a 32-bit value
+ * @param k the key (the unaligned variable-length array of bytes)
+ * @param length the length of the key, counting by bytes
+ * @param initval can be any 4-byte value
+ *
+ * A small wrapper function that selects the proper hash function based on the
+ * native machine's byte-ordering.
+ *
+ */
+uint32_t jhash(const void *key, size_t length, uint32_t initval)
+{
+	if (length % sizeof(uint32_t) == 0)
+		return jhash_word(key, (length / sizeof(uint32_t)), initval);
+	else if (arch_def_native->endian == ARCH_ENDIAN_BIG)
+		return jhash_be(key, length, initval);
+	else
+		return jhash_le(key, length, initval);
+}