lib: import ccan modules for tdb2

Imported from git://git.ozlabs.org/~ccan/ccan init-1161-g661d41f

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

5 files changed, 1717 insertions, 0 deletions

diff --git a/lib/ccan/hash/_info b/lib/ccan/hash/_info
new file mode 100644
index 0000000000..5aeb912136
--- /dev/null
+++ b/lib/ccan/hash/_info
@@ -0,0 +1,31 @@
+#include <string.h>
+#include <stdio.h>
+
+/**
+ * hash - routines for hashing bytes
+ *
+ * When creating a hash table it's important to have a hash function
+ * which mixes well and is fast.  This package supplies such functions.
+ *
+ * The hash functions come in two flavors: the normal ones and the
+ * stable ones.  The normal ones can vary from machine-to-machine and
+ * may change if we find better or faster hash algorithms in future.
+ * The stable ones will always give the same results on any computer,
+ * and on any version of this package.
+ *
+ * License: Public Domain
+ * Maintainer: Rusty Russell <rusty@rustcorp.com.au>
+ * Author: Bob Jenkins <bob_jenkins@burtleburtle.net>
+ */
+int main(int argc, char *argv[])
+{
+	if (argc != 2)
+		return 1;
+
+	if (strcmp(argv[1], "depends") == 0) {
+		printf("ccan/build_assert\n");
+		return 0;
+	}
+
+	return 1;
+}
diff --git a/lib/ccan/hash/hash.c b/lib/ccan/hash/hash.c
new file mode 100644
index 0000000000..0fd6109513
--- /dev/null
+++ b/lib/ccan/hash/hash.c
@@ -0,0 +1,925 @@
+/*
+-------------------------------------------------------------------------------
+lookup3.c, by Bob Jenkins, May 2006, Public Domain.
+
+These are functions for producing 32-bit hashes for hash table lookup.
+hash_word(), 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 hash_word().  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
+
+#if 0
+#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
+
+/*
+ * 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(__x86_64) || \
+     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
+# error Unknown endian
+#endif
+#endif /* old hash.c headers. */
+
+#include "hash.h"
+
+#if HAVE_LITTLE_ENDIAN
+#define HASH_LITTLE_ENDIAN 1
+#define HASH_BIG_ENDIAN 0
+#elif HAVE_BIG_ENDIAN
+#define HASH_LITTLE_ENDIAN 0
+#define HASH_BIG_ENDIAN 1
+#else
+#error Unknown endian
+#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 hash_word() 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 hash_word() only because
+ hashlittle() has to dance around fitting the key bytes into registers.
+--------------------------------------------------------------------
+*/
+uint32_t hash_u32(
+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;
+}
+
+/*
+-------------------------------------------------------------------------------
+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
+  val2    : IN: can be any 4-byte value OUT: second 32 bit hash.
+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.  Note that the return value is better
+mixed than val2, so use that first.
+
+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.
+-------------------------------------------------------------------------------
+*/
+
+static uint32_t hashlittle( const void *key, size_t length, uint32_t *val2 )
+{
+  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) + *val2;
+
+  u.ptr = key;
+  if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
+    const uint32_t *k = (const uint32_t *)key;         /* read 32-bit chunks */
+    const uint8_t  *k8;
+
+    /*------ 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).
+     *
+     * Not on my testing with gcc 4.5 on an intel i5 CPU, at least --RR.
+     */
+#if 0
+    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);
+  *val2 = b;
+  return c;
+}
+
+/*
+ * hashbig():
+ * This is the same as hash_word() on big-endian machines.  It is different
+ * from hashlittle() on all machines.  hashbig() takes advantage of
+ * big-endian byte ordering.
+ */
+static uint32_t hashbig( const void *key, size_t length, uint32_t *val2)
+{
+  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) + *val2;
+
+  u.ptr = key;
+  if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) {
+    const uint32_t *k = (const uint32_t *)key;         /* read 32-bit chunks */
+    const uint8_t  *k8;
+
+    /*------ 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).
+     *
+     * Not on my testing with gcc 4.5 on an intel i5 CPU, at least --RR.
+     */
+#if 0
+    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);
+  *val2 = b;
+  return c;
+}
+
+/* I basically use hashlittle here, but use native endian within each
+ * element.  This delivers least-surprise: hash such as "int arr[] = {
+ * 1, 2 }; hash_stable(arr, 2, 0);" will be the same on big and little
+ * endian machines, even though a bytewise hash wouldn't be. */
+uint64_t hash64_stable_64(const void *key, size_t n, uint64_t base)
+{
+	const uint64_t *k = key;
+	uint32_t a,b,c;
+
+	/* Set up the internal state */
+	a = b = c = 0xdeadbeef + ((uint32_t)n*8) + (base >> 32) + base;
+
+	while (n > 3) {
+		a += (uint32_t)k[0];
+		b += (uint32_t)(k[0] >> 32);
+		c += (uint32_t)k[1];
+		mix(a,b,c);
+		a += (uint32_t)(k[1] >> 32);
+		b += (uint32_t)k[2];
+		c += (uint32_t)(k[2] >> 32);
+		mix(a,b,c);
+		n -= 3;
+		k += 3;
+	}
+	switch (n) {
+	case 2:
+		a += (uint32_t)k[0];
+		b += (uint32_t)(k[0] >> 32);
+		c += (uint32_t)k[1];
+		mix(a,b,c);
+		a += (uint32_t)(k[1] >> 32);
+		break;
+	case 1:
+		a += (uint32_t)k[0];
+		b += (uint32_t)(k[0] >> 32);
+		break;
+	case 0:
+		return c;
+	}
+	final(a,b,c);
+	return ((uint64_t)b << 32) | c;
+}
+
+uint64_t hash64_stable_32(const void *key, size_t n, uint64_t base)
+{
+	const uint32_t *k = key;
+	uint32_t a,b,c;
+
+	/* Set up the internal state */
+	a = b = c = 0xdeadbeef + ((uint32_t)n*4) + (base >> 32) + base;
+
+	while (n > 3) {
+		a += k[0];
+		b += k[1];
+		c += k[2];
+		mix(a,b,c);
+
+		n -= 3;
+		k += 3;
+	}
+	switch (n) {
+	case 2:
+		b += (uint32_t)k[1];
+	case 1:
+		a += (uint32_t)k[0];
+		break;
+	case 0:
+		return c;
+	}
+	final(a,b,c);
+	return ((uint64_t)b << 32) | c;
+}
+
+uint64_t hash64_stable_16(const void *key, size_t n, uint64_t base)
+{
+	const uint16_t *k = key;
+	uint32_t a,b,c;
+
+	/* Set up the internal state */
+	a = b = c = 0xdeadbeef + ((uint32_t)n*2) + (base >> 32) + base;
+
+	while (n > 6) {
+		a += (uint32_t)k[0] + ((uint32_t)k[1] << 16);
+		b += (uint32_t)k[2] + ((uint32_t)k[3] << 16);
+		c += (uint32_t)k[4] + ((uint32_t)k[5] << 16);
+		mix(a,b,c);
+
+		n -= 6;
+		k += 6;
+	}
+
+	switch (n) {
+	case 5:
+		c += (uint32_t)k[4];
+	case 4:
+		b += ((uint32_t)k[3] << 16);
+	case 3:
+		b += (uint32_t)k[2];
+	case 2:
+		a += ((uint32_t)k[1] << 16);
+	case 1:
+		a += (uint32_t)k[0];
+		break;
+	case 0:
+		return c;
+	}
+	final(a,b,c);
+	return ((uint64_t)b << 32) | c;
+}
+
+uint64_t hash64_stable_8(const void *key, size_t n, uint64_t base)
+{
+	uint32_t b32 = base + (base >> 32);
+	uint32_t lower = hashlittle(key, n, &b32);
+
+	return ((uint64_t)b32 << 32) | lower;
+}
+
+uint32_t hash_any(const void *key, size_t length, uint32_t base)
+{
+	if (HASH_BIG_ENDIAN)
+		return hashbig(key, length, &base);
+	else
+		return hashlittle(key, length, &base);
+}
+
+uint32_t hash_stable_64(const void *key, size_t n, uint32_t base)
+{
+	return hash64_stable_64(key, n, base);
+}
+
+uint32_t hash_stable_32(const void *key, size_t n, uint32_t base)
+{
+	return hash64_stable_32(key, n, base);
+}
+
+uint32_t hash_stable_16(const void *key, size_t n, uint32_t base)
+{
+	return hash64_stable_16(key, n, base);
+}
+
+uint32_t hash_stable_8(const void *key, size_t n, uint32_t base)
+{
+	return hashlittle(key, n, &base);
+}
+
+/* Jenkins' lookup8 is a 64 bit hash, but he says it's obsolete.  Use
+ * the plain one and recombine into 64 bits. */
+uint64_t hash64_any(const void *key, size_t length, uint64_t base)
+{
+	uint32_t b32 = base + (base >> 32);
+	uint32_t lower;
+
+	if (HASH_BIG_ENDIAN)
+		lower = hashbig(key, length, &b32);
+	else
+		lower = hashlittle(key, length, &b32);
+
+	return ((uint64_t)b32 << 32) | lower;
+}
+
+#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 several 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",
+         hash_word((const uint32_t *)q, (sizeof(q)-1)/4, 13),
+         hash_word((const uint32_t *)q, (sizeof(q)-5)/4, 13),
+         hash_word((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 hash_word2 and hash_word produce the same results */
+  len = 0xdeadbeef;
+  i=47, j=0;
+  hash_word2(&len, 1, &i, &j);
+  if (hash_word(&len, 1, 47) != i)
+    printf("hash_word2 and hash_word mismatch %x %x\n",
+	   i, hash_word(&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);
+  }
+}
+
+
+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) */
+  return 1;
+}
+
+#endif  /* SELF_TEST */
diff --git a/lib/ccan/hash/hash.h b/lib/ccan/hash/hash.h
new file mode 100644
index 0000000000..5025c0d748
--- /dev/null
+++ b/lib/ccan/hash/hash.h
@@ -0,0 +1,312 @@
+#ifndef CCAN_HASH_H
+#define CCAN_HASH_H
+#include "config.h"
+#include <stdint.h>
+#include <stdlib.h>
+#include <ccan/build_assert/build_assert.h>
+
+/* Stolen mostly from: lookup3.c, by Bob Jenkins, May 2006, Public Domain.
+ *
+ * http://burtleburtle.net/bob/c/lookup3.c
+ */
+
+/**
+ * hash - fast hash of an array for internal use
+ * @p: the array or pointer to first element
+ * @num: the number of elements to hash
+ * @base: the base number to roll into the hash (usually 0)
+ *
+ * The memory region pointed to by p is combined with the base to form
+ * a 32-bit hash.
+ *
+ * This hash will have different results on different machines, so is
+ * only useful for internal hashes (ie. not hashes sent across the
+ * network or saved to disk).
+ *
+ * It may also change with future versions: it could even detect at runtime
+ * what the fastest hash to use is.
+ *
+ * See also: hash64, hash_stable.
+ *
+ * Example:
+ *	#include <ccan/hash/hash.h>
+ *	#include <err.h>
+ *	#include <stdio.h>
+ *	#include <string.h>
+ *
+ *	// Simple demonstration: idential strings will have the same hash, but
+ *	// two different strings will probably not.
+ *	int main(int argc, char *argv[])
+ *	{
+ *		uint32_t hash1, hash2;
+ *
+ *		if (argc != 3)
+ *			err(1, "Usage: %s <string1> <string2>", argv[0]);
+ *
+ *		hash1 = hash(argv[1], strlen(argv[1]), 0);
+ *		hash2 = hash(argv[2], strlen(argv[2]), 0);
+ *		printf("Hash is %s\n", hash1 == hash2 ? "same" : "different");
+ *		return 0;
+ *	}
+ */
+#define hash(p, num, base) hash_any((p), (num)*sizeof(*(p)), (base))
+
+/**
+ * hash_stable - hash of an array for external use
+ * @p: the array or pointer to first element
+ * @num: the number of elements to hash
+ * @base: the base number to roll into the hash (usually 0)
+ *
+ * The array of simple integer types pointed to by p is combined with
+ * the base to form a 32-bit hash.
+ *
+ * This hash will have the same results on different machines, so can
+ * be used for external hashes (ie. hashes sent across the network or
+ * saved to disk).  The results will not change in future versions of
+ * this module.
+ *
+ * Note that it is only legal to hand an array of simple integer types
+ * to this hash (ie. char, uint16_t, int64_t, etc).  In these cases,
+ * the same values will have the same hash result, even though the
+ * memory representations of integers depend on the machine
+ * endianness.
+ *
+ * See also:
+ *	hash64_stable
+ *
+ * Example:
+ *	#include <ccan/hash/hash.h>
+ *	#include <err.h>
+ *	#include <stdio.h>
+ *	#include <string.h>
+ *
+ *	int main(int argc, char *argv[])
+ *	{
+ *		if (argc != 2)
+ *			err(1, "Usage: %s <string-to-hash>", argv[0]);
+ *
+ *		printf("Hash stable result is %u\n",
+ *		       hash_stable(argv[1], strlen(argv[1]), 0));
+ *		return 0;
+ *	}
+ */
+#define hash_stable(p, num, base)					\
+	(BUILD_ASSERT_OR_ZERO(sizeof(*(p)) == 8 || sizeof(*(p)) == 4	\
+			      || sizeof(*(p)) == 2 || sizeof(*(p)) == 1) + \
+	 sizeof(*(p)) == 8 ? hash_stable_64((p), (num), (base))		\
+	 : sizeof(*(p)) == 4 ? hash_stable_32((p), (num), (base))	\
+	 : sizeof(*(p)) == 2 ? hash_stable_16((p), (num), (base))	\
+	 : hash_stable_8((p), (num), (base)))
+
+/**
+ * hash_u32 - fast hash an array of 32-bit values for internal use
+ * @key: the array of uint32_t
+ * @num: the number of elements to hash
+ * @base: the base number to roll into the hash (usually 0)
+ *
+ * The array of uint32_t pointed to by @key is combined with the base
+ * to form a 32-bit hash.  This is 2-3 times faster than hash() on small
+ * arrays, but the advantage vanishes over large hashes.
+ *
+ * This hash will have different results on different machines, so is
+ * only useful for internal hashes (ie. not hashes sent across the
+ * network or saved to disk).
+ */
+uint32_t hash_u32(const uint32_t *key, size_t num, uint32_t base);
+
+/**
+ * hash_string - very fast hash of an ascii string
+ * @str: the nul-terminated string
+ *
+ * The string is hashed, using a hash function optimized for ASCII and
+ * similar strings.  It's weaker than the other hash functions.
+ *
+ * This hash may have different results on different machines, so is
+ * only useful for internal hashes (ie. not hashes sent across the
+ * network or saved to disk).  The results will be different from the
+ * other hash functions in this module, too.
+ */
+static inline uint32_t hash_string(const char *string)
+{
+	/* This is Karl Nelson <kenelson@ece.ucdavis.edu>'s X31 hash.
+	 * It's a little faster than the (much better) lookup3 hash(): 56ns vs
+	 * 84ns on my 2GHz Intel Core Duo 2 laptop for a 10 char string. */
+	uint32_t ret;
+
+	for (ret = 0; *string; string++)
+		ret = (ret << 5) - ret + *string;
+
+	return ret;
+}
+
+/**
+ * hash64 - fast 64-bit hash of an array for internal use
+ * @p: the array or pointer to first element
+ * @num: the number of elements to hash
+ * @base: the 64-bit base number to roll into the hash (usually 0)
+ *
+ * The memory region pointed to by p is combined with the base to form
+ * a 64-bit hash.
+ *
+ * This hash will have different results on different machines, so is
+ * only useful for internal hashes (ie. not hashes sent across the
+ * network or saved to disk).
+ *
+ * It may also change with future versions: it could even detect at runtime
+ * what the fastest hash to use is.
+ *
+ * See also: hash.
+ *
+ * Example:
+ *	#include <ccan/hash/hash.h>
+ *	#include <err.h>
+ *	#include <stdio.h>
+ *	#include <string.h>
+ *
+ *	// Simple demonstration: idential strings will have the same hash, but
+ *	// two different strings will probably not.
+ *	int main(int argc, char *argv[])
+ *	{
+ *		uint64_t hash1, hash2;
+ *
+ *		if (argc != 3)
+ *			err(1, "Usage: %s <string1> <string2>", argv[0]);
+ *
+ *		hash1 = hash64(argv[1], strlen(argv[1]), 0);
+ *		hash2 = hash64(argv[2], strlen(argv[2]), 0);
+ *		printf("Hash is %s\n", hash1 == hash2 ? "same" : "different");
+ *		return 0;
+ *	}
+ */
+#define hash64(p, num, base) hash64_any((p), (num)*sizeof(*(p)), (base))
+
+/**
+ * hash64_stable - 64 bit hash of an array for external use
+ * @p: the array or pointer to first element
+ * @num: the number of elements to hash
+ * @base: the base number to roll into the hash (usually 0)
+ *
+ * The array of simple integer types pointed to by p is combined with
+ * the base to form a 64-bit hash.
+ *
+ * This hash will have the same results on different machines, so can
+ * be used for external hashes (ie. hashes sent across the network or
+ * saved to disk).  The results will not change in future versions of
+ * this module.
+ *
+ * Note that it is only legal to hand an array of simple integer types
+ * to this hash (ie. char, uint16_t, int64_t, etc).  In these cases,
+ * the same values will have the same hash result, even though the
+ * memory representations of integers depend on the machine
+ * endianness.
+ *
+ * See also:
+ *	hash_stable
+ *
+ * Example:
+ *	#include <ccan/hash/hash.h>
+ *	#include <err.h>
+ *	#include <stdio.h>
+ *	#include <string.h>
+ *
+ *	int main(int argc, char *argv[])
+ *	{
+ *		if (argc != 2)
+ *			err(1, "Usage: %s <string-to-hash>", argv[0]);
+ *
+ *		printf("Hash stable result is %llu\n",
+ *		       (long long)hash64_stable(argv[1], strlen(argv[1]), 0));
+ *		return 0;
+ *	}
+ */
+#define hash64_stable(p, num, base)					\
+	(BUILD_ASSERT_OR_ZERO(sizeof(*(p)) == 8 || sizeof(*(p)) == 4	\
+			      || sizeof(*(p)) == 2 || sizeof(*(p)) == 1) + \
+	 sizeof(*(p)) == 8 ? hash64_stable_64((p), (num), (base))	\
+	 : sizeof(*(p)) == 4 ? hash64_stable_32((p), (num), (base))	\
+	 : sizeof(*(p)) == 2 ? hash64_stable_16((p), (num), (base))	\
+	 : hash64_stable_8((p), (num), (base)))
+
+
+/**
+ * hashl - fast 32/64-bit hash of an array for internal use
+ * @p: the array or pointer to first element
+ * @num: the number of elements to hash
+ * @base: the base number to roll into the hash (usually 0)
+ *
+ * This is either hash() or hash64(), on 32/64 bit long machines.
+ */
+#define hashl(p, num, base)						\
+	(BUILD_ASSERT_OR_ZERO(sizeof(long) == sizeof(uint32_t)		\
+			      || sizeof(long) == sizeof(uint64_t)) +	\
+	(sizeof(long) == sizeof(uint64_t)				\
+	 ? hash64((p), (num), (base)) : hash((p), (num), (base))))
+
+/* Our underlying operations. */
+uint32_t hash_any(const void *key, size_t length, uint32_t base);
+uint32_t hash_stable_64(const void *key, size_t n, uint32_t base);
+uint32_t hash_stable_32(const void *key, size_t n, uint32_t base);
+uint32_t hash_stable_16(const void *key, size_t n, uint32_t base);
+uint32_t hash_stable_8(const void *key, size_t n, uint32_t base);
+uint64_t hash64_any(const void *key, size_t length, uint64_t base);
+uint64_t hash64_stable_64(const void *key, size_t n, uint64_t base);
+uint64_t hash64_stable_32(const void *key, size_t n, uint64_t base);
+uint64_t hash64_stable_16(const void *key, size_t n, uint64_t base);
+uint64_t hash64_stable_8(const void *key, size_t n, uint64_t base);
+
+/**
+ * hash_pointer - hash a pointer for internal use
+ * @p: the pointer value to hash
+ * @base: the base number to roll into the hash (usually 0)
+ *
+ * The pointer p (not what p points to!) is combined with the base to form
+ * a 32-bit hash.
+ *
+ * This hash will have different results on different machines, so is
+ * only useful for internal hashes (ie. not hashes sent across the
+ * network or saved to disk).
+ *
+ * Example:
+ *	#include <ccan/hash/hash.h>
+ *
+ *	// Code to keep track of memory regions.
+ *	struct region {
+ *		struct region *chain;
+ *		void *start;
+ *		unsigned int size;
+ *	};
+ *	// We keep a simple hash table.
+ *	static struct region *region_hash[128];
+ *
+ *	static void add_region(struct region *r)
+ *	{
+ *		unsigned int h = hash_pointer(r->start, 0);
+ *
+ *		r->chain = region_hash[h];
+ *		region_hash[h] = r->chain;
+ *	}
+ *
+ *	static struct region *find_region(const void *start)
+ *	{
+ *		struct region *r;
+ *
+ *		for (r = region_hash[hash_pointer(start, 0)]; r; r = r->chain)
+ *			if (r->start == start)
+ *				return r;
+ *		return NULL;
+ *	}
+ */
+static inline uint32_t hash_pointer(const void *p, uint32_t base)
+{
+	if (sizeof(p) % sizeof(uint32_t) == 0) {
+		/* This convoluted union is the right way of aliasing. */
+		union {
+			uint32_t u32[sizeof(p) / sizeof(uint32_t)];
+			const void *p;
+		} u;
+		u.p = p;
+		return hash_u32(u.u32, sizeof(p) / sizeof(uint32_t), base);
+	} else
+		return hash(&p, 1, base);
+}
+#endif /* HASH_H */
diff --git a/lib/ccan/hash/test/api-hash_stable.c b/lib/ccan/hash/test/api-hash_stable.c
new file mode 100644
index 0000000000..bb58d16b18
--- /dev/null
+++ b/lib/ccan/hash/test/api-hash_stable.c
@@ -0,0 +1,300 @@
+#include <ccan/hash/hash.h>
+#include <ccan/tap/tap.h>
+#include <stdbool.h>
+#include <string.h>
+
+#define ARRAY_WORDS 5
+
+int main(int argc, char *argv[])
+{
+	unsigned int i;
+	uint8_t u8array[ARRAY_WORDS];
+	uint16_t u16array[ARRAY_WORDS];
+	uint32_t u32array[ARRAY_WORDS];
+	uint64_t u64array[ARRAY_WORDS];
+
+	/* Initialize arrays. */
+	for (i = 0; i < ARRAY_WORDS; i++) {
+		u8array[i] = i;
+		u16array[i] = i;
+		u32array[i] = i;
+		u64array[i] = i;
+	}
+
+	plan_tests(264);
+
+	/* hash_stable is API-guaranteed. */
+	ok1(hash_stable(u8array, ARRAY_WORDS, 0) == 0x1d4833cc);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 1) == 0x37125e2 );
+	ok1(hash_stable(u8array, ARRAY_WORDS, 2) == 0x330a007a);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 4) == 0x7b0df29b);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 8) == 0xe7e5d741);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 16) == 0xaae57471);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 32) == 0xc55399e5);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 64) == 0x67f21f7 );
+	ok1(hash_stable(u8array, ARRAY_WORDS, 128) == 0x1d795b71);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 256) == 0xeb961671);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 512) == 0xc2597247);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 1024) == 0x3f5c4d75);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 2048) == 0xe65cf4f9);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 4096) == 0xf2cd06cb);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 8192) == 0x443041e1);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 16384) == 0xdfc618f5);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 32768) == 0x5e3d5b97);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 65536) == 0xd5f64730);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 131072) == 0x372bbecc);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 262144) == 0x7c194c8d);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 524288) == 0x16cbb416);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 1048576) == 0x53e99222);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 2097152) == 0x6394554a);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 4194304) == 0xd83a506d);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 8388608) == 0x7619d9a4);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 16777216) == 0xfe98e5f6);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 33554432) == 0x6c262927);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 67108864) == 0x3f0106fd);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 134217728) == 0xc91e3a28);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 268435456) == 0x14229579);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 536870912) == 0x9dbefa76);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 1073741824) == 0xb05c0c78);
+	ok1(hash_stable(u8array, ARRAY_WORDS, 2147483648U) == 0x88f24d81);
+
+	ok1(hash_stable(u16array, ARRAY_WORDS, 0) == 0xecb5f507);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 1) == 0xadd666e6);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 2) == 0xea0f214c);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 4) == 0xae4051ba);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 8) == 0x6ed28026);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 16) == 0xa3917a19);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 32) == 0xf370f32b);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 64) == 0x807af460);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 128) == 0xb4c8cd83);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 256) == 0xa10cb5b0);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 512) == 0x8b7d7387);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 1024) == 0x9e49d1c );
+	ok1(hash_stable(u16array, ARRAY_WORDS, 2048) == 0x288830d1);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 4096) == 0xbe078a43);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 8192) == 0xa16d5d88);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 16384) == 0x46839fcd);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 32768) == 0x9db9bd4f);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 65536) == 0xedff58f8);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 131072) == 0x95ecef18);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 262144) == 0x23c31b7d);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 524288) == 0x1d85c7d0);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 1048576) == 0x25218842);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 2097152) == 0x711d985c);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 4194304) == 0x85470eca);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 8388608) == 0x99ed4ceb);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 16777216) == 0x67b3710c);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 33554432) == 0x77f1ab35);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 67108864) == 0x81f688aa);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 134217728) == 0x27b56ca5);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 268435456) == 0xf21ba203);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 536870912) == 0xd48d1d1 );
+	ok1(hash_stable(u16array, ARRAY_WORDS, 1073741824) == 0xa542b62d);
+	ok1(hash_stable(u16array, ARRAY_WORDS, 2147483648U) == 0xa04c7058);
+
+	ok1(hash_stable(u32array, ARRAY_WORDS, 0) == 0x13305f8c);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 1) == 0x171abf74);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 2) == 0x7646fcc7);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 4) == 0xa758ed5);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 8) == 0x2dedc2e4);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 16) == 0x28e2076b);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 32) == 0xb73091c5);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 64) == 0x87daf5db);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 128) == 0xa16dfe20);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 256) == 0x300c63c3);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 512) == 0x255c91fc);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 1024) == 0x6357b26);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 2048) == 0x4bc5f339);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 4096) == 0x1301617c);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 8192) == 0x506792c9);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 16384) == 0xcd596705);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 32768) == 0xa8713cac);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 65536) == 0x94d9794);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 131072) == 0xac753e8);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 262144) == 0xcd8bdd20);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 524288) == 0xd44faf80);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 1048576) == 0x2547ccbe);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 2097152) == 0xbab06dbc);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 4194304) == 0xaac0e882);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 8388608) == 0x443f48d0);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 16777216) == 0xdff49fcc);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 33554432) == 0x9ce0fd65);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 67108864) == 0x9ddb1def);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 134217728) == 0x86096f25);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 268435456) == 0xe713b7b5);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 536870912) == 0x5baeffc5);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 1073741824) == 0xde874f52);
+	ok1(hash_stable(u32array, ARRAY_WORDS, 2147483648U) == 0xeca13b4e);
+
+	ok1(hash_stable(u64array, ARRAY_WORDS, 0) == 0x12ef6302);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 1) == 0xe9aeb406);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 2) == 0xc4218ceb);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 4) == 0xb3d11412);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 8) == 0xdafbd654);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 16) == 0x9c336cba);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 32) == 0x65059721);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 64) == 0x95b5bbe6);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 128) == 0xe7596b84);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 256) == 0x503622a2);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 512) == 0xecdcc5ca);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 1024) == 0xc40d0513);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 2048) == 0xaab25e4d);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 4096) == 0xcc353fb9);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 8192) == 0x18e2319f);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 16384) == 0xfddaae8d);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 32768) == 0xef7976f2);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 65536) == 0x86359fc9);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 131072) == 0x8b5af385);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 262144) == 0x80d4ee31);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 524288) == 0x42f5f85b);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 1048576) == 0x9a6920e1);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 2097152) == 0x7b7c9850);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 4194304) == 0x69573e09);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 8388608) == 0xc942bc0e);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 16777216) == 0x7a89f0f1);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 33554432) == 0x2dd641ca);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 67108864) == 0x89bbd391);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 134217728) == 0xbcf88e31);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 268435456) == 0xfa7a3460);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 536870912) == 0x49a37be0);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 1073741824) == 0x1b346394);
+	ok1(hash_stable(u64array, ARRAY_WORDS, 2147483648U) == 0x6c3a1592);
+
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 0) == 16887282882572727244ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 1) == 12032777473133454818ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 2) == 18183407363221487738ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 4) == 17860764172704150171ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 8) == 18076051600675559233ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 16) == 9909361918431556721ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 32) == 12937969888744675813ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 64) == 5245669057381736951ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 128) == 4376874646406519665ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 256) == 14219974419871569521ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 512) == 2263415354134458951ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 1024) == 4953859694526221685ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 2048) == 3432228642067641593ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 4096) == 1219647244417697483ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 8192) == 7629939424585859553ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 16384) == 10041660531376789749ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 32768) == 13859885793922603927ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 65536) == 15069060338344675120ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 131072) == 818163430835601100ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 262144) == 14914314323019517069ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 524288) == 17518437749769352214ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 1048576) == 14920048004901212706ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 2097152) == 8758567366332536138ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 4194304) == 6226655736088907885ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 8388608) == 13716650013685832100ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 16777216) == 305325651636315638ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 33554432) == 16784147606583781671ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 67108864) == 16509467555140798205ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 134217728) == 8717281234694060584ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 268435456) == 8098476701725660537ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 536870912) == 16345871539461094006ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 1073741824) == 3755557000429964408ULL);
+	ok1(hash64_stable(u8array, ARRAY_WORDS, 2147483648U) == 15017348801959710081ULL);
+
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 0) == 1038028831307724039ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 1) == 10155473272642627302ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 2) == 5714751190106841420ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 4) == 3923885607767527866ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 8) == 3931017318293995558ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 16) == 1469696588339313177ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 32) == 11522218526952715051ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 64) == 6953517591561958496ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 128) == 7406689491740052867ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 256) == 10101844489704093104ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 512) == 12511348870707245959ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 1024) == 1614019938016861468ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 2048) == 5294796182374592721ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 4096) == 16089570706643716675ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 8192) == 1689302638424579464ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 16384) == 1446340172370386893ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 32768) == 16535503506744393039ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 65536) == 3496794142527150328ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 131072) == 6568245367474548504ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 262144) == 9487676460765485949ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 524288) == 4519762130966530000ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 1048576) == 15623412069215340610ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 2097152) == 544013388676438108ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 4194304) == 5594904760290840266ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 8388608) == 18098755780041592043ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 16777216) == 6389168672387330316ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 33554432) == 896986127732419381ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 67108864) == 13232626471143901354ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 134217728) == 53378562890493093ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 268435456) == 10072361400297824771ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 536870912) == 14511948118285144529ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 1073741824) == 6981033484844447277ULL);
+	ok1(hash64_stable(u16array, ARRAY_WORDS, 2147483648U) == 5619339091684126808ULL);
+
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 0) == 3037571077312110476ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 1) == 14732398743825071988ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 2) == 14949132158206672071ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 4) == 1291370080511561429ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 8) == 10792665964172133092ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 16) == 14250138032054339435ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 32) == 17136741522078732741ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 64) == 3260193403318236635ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 128) == 10526616652205653536ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 256) == 9019690373358576579ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 512) == 6997491436599677436ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 1024) == 18302783371416533798ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 2048) == 10149320644446516025ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 4096) == 7073759949410623868ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 8192) == 17442399482223760073ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 16384) == 2983906194216281861ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 32768) == 4975845419129060524ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 65536) == 594019910205413268ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 131072) == 11903010186073691112ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 262144) == 7339636527154847008ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 524288) == 15243305400579108736ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 1048576) == 16737926245392043198ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 2097152) == 15725083267699862972ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 4194304) == 12527834265678833794ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 8388608) == 13908436455987824848ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 16777216) == 9672773345173872588ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 33554432) == 2305314279896710501ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 67108864) == 1866733780381408751ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 134217728) == 11906263969465724709ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 268435456) == 5501594918093830069ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 536870912) == 15823785789276225477ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 1073741824) == 17353000723889475410ULL);
+	ok1(hash64_stable(u32array, ARRAY_WORDS, 2147483648U) == 7494736910655503182ULL);
+
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 0) == 9765419389786481410ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 1) == 11182806172127114246ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 2) == 2559155171395472619ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 4) == 3311692033324815378ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 8) == 1297175419505333844ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 16) == 617896928653569210ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 32) == 1517398559958603553ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 64) == 4504821917445110758ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 128) == 1971743331114904452ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 256) == 6177667912354374306ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 512) == 15570521289777792458ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 1024) == 9204559632415917331ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 2048) == 9008982669760028237ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 4096) == 14803537660281700281ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 8192) == 2873966517448487327ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 16384) == 5859277625928363661ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 32768) == 15520461285618185970ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 65536) == 16746489793331175369ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 131072) == 514952025484227461ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 262144) == 10867212269810675249ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 524288) == 9822204377278314587ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 1048576) == 3295088921987850465ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 2097152) == 7559197431498053712ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 4194304) == 1667267269116771849ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 8388608) == 2916804068951374862ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 16777216) == 14422558383125688561ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 33554432) == 10083112683694342602ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 67108864) == 7222777647078298513ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 134217728) == 18424513674048212529ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 268435456) == 14913668581101810784ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 536870912) == 14377721174297902048ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 1073741824) == 6031715005667500948ULL);
+	ok1(hash64_stable(u64array, ARRAY_WORDS, 2147483648U) == 4827100319722378642ULL);
+
+	return exit_status();
+}
diff --git a/lib/ccan/hash/test/run.c b/lib/ccan/hash/test/run.c
new file mode 100644
index 0000000000..dad8e86b9e
--- /dev/null
+++ b/lib/ccan/hash/test/run.c
@@ -0,0 +1,149 @@
+#include <ccan/hash/hash.h>
+#include <ccan/tap/tap.h>
+#include <ccan/hash/hash.c>
+#include <stdbool.h>
+#include <string.h>
+
+#define ARRAY_WORDS 5
+
+int main(int argc, char *argv[])
+{
+	unsigned int i, j, k;
+	uint32_t array[ARRAY_WORDS], val;
+	char array2[sizeof(array) + sizeof(uint32_t)];
+	uint32_t results[256];
+
+	/* Initialize array. */
+	for (i = 0; i < ARRAY_WORDS; i++)
+		array[i] = i;
+
+	plan_tests(39);
+	/* Hash should be the same, indep of memory alignment. */
+	val = hash(array, ARRAY_WORDS, 0);
+	for (i = 0; i < sizeof(uint32_t); i++) {
+		memcpy(array2 + i, array, sizeof(array));
+		ok(hash(array2 + i, ARRAY_WORDS, 0) != val,
+		   "hash matched at offset %i", i);
+	}
+
+	/* Hash of random values should have random distribution:
+	 * check one byte at a time. */
+	for (i = 0; i < sizeof(uint32_t); i++) {
+		unsigned int lowest = -1U, highest = 0;
+
+		memset(results, 0, sizeof(results));
+
+		for (j = 0; j < 256000; j++) {
+			for (k = 0; k < ARRAY_WORDS; k++)
+				array[k] = random();
+			results[(hash(array, ARRAY_WORDS, 0) >> i*8)&0xFF]++;
+		}
+
+		for (j = 0; j < 256; j++) {
+			if (results[j] < lowest)
+				lowest = results[j];
+			if (results[j] > highest)
+				highest = results[j];
+		}
+		/* Expect within 20% */
+		ok(lowest > 800, "Byte %i lowest %i", i, lowest);
+		ok(highest < 1200, "Byte %i highest %i", i, highest);
+		diag("Byte %i, range %u-%u", i, lowest, highest);
+	}
+
+	/* Hash of random values should have random distribution:
+	 * check one byte at a time. */
+	for (i = 0; i < sizeof(uint64_t); i++) {
+		unsigned int lowest = -1U, highest = 0;
+
+		memset(results, 0, sizeof(results));
+
+		for (j = 0; j < 256000; j++) {
+			for (k = 0; k < ARRAY_WORDS; k++)
+				array[k] = random();
+			results[(hash64(array, sizeof(array)/sizeof(uint64_t),
+					0) >> i*8)&0xFF]++;
+		}
+
+		for (j = 0; j < 256; j++) {
+			if (results[j] < lowest)
+				lowest = results[j];
+			if (results[j] > highest)
+				highest = results[j];
+		}
+		/* Expect within 20% */
+		ok(lowest > 800, "Byte %i lowest %i", i, lowest);
+		ok(highest < 1200, "Byte %i highest %i", i, highest);
+		diag("Byte %i, range %u-%u", i, lowest, highest);
+	}
+
+	/* Hash of pointer values should also have random distribution. */
+	for (i = 0; i < sizeof(uint32_t); i++) {
+		unsigned int lowest = -1U, highest = 0;
+		char *p = malloc(256000);
+
+		memset(results, 0, sizeof(results));
+
+		for (j = 0; j < 256000; j++)
+			results[(hash_pointer(p + j, 0) >> i*8)&0xFF]++;
+		free(p);
+
+		for (j = 0; j < 256; j++) {
+			if (results[j] < lowest)
+				lowest = results[j];
+			if (results[j] > highest)
+				highest = results[j];
+		}
+		/* Expect within 20% */
+		ok(lowest > 800, "hash_pointer byte %i lowest %i", i, lowest);
+		ok(highest < 1200, "hash_pointer byte %i highest %i",
+		   i, highest);
+		diag("hash_pointer byte %i, range %u-%u", i, lowest, highest);
+	}
+
+	if (sizeof(long) == sizeof(uint32_t))
+		ok1(hashl(array, ARRAY_WORDS, 0)
+		    == hash(array, ARRAY_WORDS, 0));
+	else
+		ok1(hashl(array, ARRAY_WORDS, 0)
+		    == hash64(array, ARRAY_WORDS, 0));
+
+	/* String hash: weak, so only test bottom byte */
+	for (i = 0; i < 1; i++) {
+		unsigned int num = 0, cursor, lowest = -1U, highest = 0;
+		char p[5];
+
+		memset(results, 0, sizeof(results));
+
+		memset(p, 'A', sizeof(p));
+		p[sizeof(p)-1] = '\0';
+
+		for (;;) {
+			for (cursor = 0; cursor < sizeof(p)-1; cursor++) {
+				p[cursor]++;
+				if (p[cursor] <= 'z')
+					break;
+				p[cursor] = 'A';
+			}
+			if (cursor == sizeof(p)-1)
+				break;
+
+			results[(hash_string(p) >> i*8)&0xFF]++;
+			num++;
+		}
+
+		for (j = 0; j < 256; j++) {
+			if (results[j] < lowest)
+				lowest = results[j];
+			if (results[j] > highest)
+				highest = results[j];
+		}
+		/* Expect within 20% */
+		ok(lowest > 35000, "hash_pointer byte %i lowest %i", i, lowest);
+		ok(highest < 53000, "hash_pointer byte %i highest %i",
+		   i, highest);
+		diag("hash_pointer byte %i, range %u-%u", i, lowest, highest);
+	}
+
+	return exit_status();
+}