Proper checksum function implemented

3 files changed, 777 insertions, 3 deletions

diff --git a/tests/arthur/common/baselineprotocol.cpp b/tests/arthur/common/baselineprotocol.cpp
index a6306b9..f2b719f 100644
--- a/tests/arthur/common/baselineprotocol.cpp
+++ b/tests/arthur/common/baselineprotocol.cpp
@@ -38,10 +38,38 @@ ImageItem &ImageItem::operator=(const ImageItem &other)
     return *this;
 }
 
+// Defined in lookup3.c:
+void hashword2 (
+const quint32 *k,                   /* the key, an array of quint32 values */
+size_t          length,               /* the length of the key, in quint32s */
+quint32       *pc,                      /* IN: seed OUT: primary hash value */
+quint32       *pb);               /* IN: more seed OUT: secondary hash value */
+
 quint64 ImageItem::computeChecksum(const QImage &image)
 {
-    //### Just fake it for now
-    return qChecksum((const char *)image.constScanLine(50), image.bytesPerLine());
+    quint32 h1 = 0xfeedbacc;
+    quint32 h2 = 0x21604894;
+
+    QImage img(image);
+    const int bpl = img.bytesPerLine();
+    const int padBytes = bpl - (img.width() * img.depth() / 8);
+    if (padBytes) {
+        uchar *p = img.bits() + bpl - padBytes;
+        const int h = img.height();
+        for (int y = 0; y < h; ++y) {
+            qMemSet(p, 0, padBytes);
+            p += bpl;
+        }
+    }
+    if (img.format() == QImage::Format_RGB32) {    // Thank you, Haavard
+        quint32 *p = (quint32 *)img.bits();
+        const quint32 *end = p + (img.byteCount()/4);
+        while (p<end)
+            *p++ &= RGB_MASK;
+    }
+
+    hashword2((const quint32 *)img.constBits(), img.byteCount()/4, &h1, &h2);
+    return (quint64(h1) << 32) | h2;
 }
 
 QDataStream & operator<< (QDataStream &stream, const ImageItem &ii)
diff --git a/tests/arthur/common/baselineprotocol.pri b/tests/arthur/common/baselineprotocol.pri
index 338339e..996f9d5 100644
--- a/tests/arthur/common/baselineprotocol.pri
+++ b/tests/arthur/common/baselineprotocol.pri
@@ -3,7 +3,8 @@ INCLUDEPATH += $$PWD
 QT *= network
 
 SOURCES += \
-        $$PWD/baselineprotocol.cpp
+        $$PWD/baselineprotocol.cpp \
+        $$PWD/lookup3.cpp
 
 HEADERS += \
         $$PWD/baselineprotocol.h
diff --git a/tests/arthur/common/lookup3.cpp b/tests/arthur/common/lookup3.cpp
new file mode 100644
index 0000000..3156a7a
--- /dev/null
+++ b/tests/arthur/common/lookup3.cpp
@@ -0,0 +1,745 @@
+
+/*
+-------------------------------------------------------------------------------
+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.
+-------------------------------------------------------------------------------
+*/
+
+// Qt'ified by Nokia.
+
+#include <QtGlobal>
+
+#if Q_BYTE_ORDER == Q_BIG_ENDIAN
+# define HASH_LITTLE_ENDIAN 0
+# define HASH_BIG_ENDIAN 1
+#else
+# define HASH_LITTLE_ENDIAN 1
+# define HASH_BIG_ENDIAN 0
+#endif
+
+#define hashsize(n) ((quint32)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 quint32's, and
+ -- that the length be the number of quint32'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 quint32s rather than in
+ bytes.  hashlittle() is more complicated than hashword() only because
+ hashlittle() has to dance around fitting the key bytes into registers.
+--------------------------------------------------------------------
+*/
+quint32 hashword(
+const quint32 *k,                   /* the key, an array of quint32 values */
+size_t          length,               /* the length of the key, in quint32s */
+quint32        initval)         /* the previous hash, or an arbitrary value */
+{
+  quint32 a,b,c;
+
+  /* Set up the internal state */
+  a = b = c = 0xdeadbeef + (((quint32)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 quint32's */
+  switch(length)                     /* all the case statements fall through */
+  { 
+  case 3 : c+=k[2];
+  case 2 : b+=k[1];
+  case 1 : a+=k[0];
+    final(a,b,c);
+  case 0:     /* case 0: nothing left to add */
+    break;
+  }
+  /*------------------------------------------------------ report the result */
+  return c;
+}
+
+
+/*
+--------------------------------------------------------------------
+hashword2() -- same as hashword(), but take two seeds and return two
+32-bit values.  pc and pb must both be nonnull, and *pc and *pb must
+both be initialized with seeds.  If you pass in (*pb)==0, the output 
+(*pc) will be the same as the return value from hashword().
+--------------------------------------------------------------------
+*/
+void hashword2 (
+const quint32 *k,                   /* the key, an array of quint32 values */
+size_t          length,               /* the length of the key, in quint32s */
+quint32       *pc,                      /* IN: seed OUT: primary hash value */
+quint32       *pb)               /* IN: more seed OUT: secondary hash value */
+{
+  quint32 a,b,c;
+
+  /* Set up the internal state */
+  a = b = c = 0xdeadbeef + ((quint32)(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 quint32'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 (quint8 **)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.
+-------------------------------------------------------------------------------
+*/
+
+quint32 hashlittle( const void *key, size_t length, quint32 initval)
+{
+  quint32 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 + ((quint32)length) + initval;
+
+  u.ptr = key;
+  if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
+    const quint32 *k = (const quint32 *)key;         /* read 32-bit 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 : return c;              /* zero length strings require no mixing */
+    }
+
+#else /* make valgrind happy */
+
+    const quint8  *k8 = (const quint8 *)k;
+    switch(length)
+    {
+    case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
+    case 11: c+=((quint32)k8[10])<<16;  /* fall through */
+    case 10: c+=((quint32)k8[9])<<8;    /* fall through */
+    case 9 : c+=k8[8];                   /* fall through */
+    case 8 : b+=k[1]; a+=k[0]; break;
+    case 7 : b+=((quint32)k8[6])<<16;   /* fall through */
+    case 6 : b+=((quint32)k8[5])<<8;    /* fall through */
+    case 5 : b+=k8[4];                   /* fall through */
+    case 4 : a+=k[0]; break;
+    case 3 : a+=((quint32)k8[2])<<16;   /* fall through */
+    case 2 : a+=((quint32)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 quint16 *k = (const quint16 *)key;         /* read 16-bit chunks */
+    const quint8  *k8;
+
+    /*--------------- all but last block: aligned reads and different mixing */
+    while (length > 12)
+    {
+      a += k[0] + (((quint32)k[1])<<16);
+      b += k[2] + (((quint32)k[3])<<16);
+      c += k[4] + (((quint32)k[5])<<16);
+      mix(a,b,c);
+      length -= 12;
+      k += 6;
+    }
+
+    /*----------------------------- handle the last (probably partial) block */
+    k8 = (const quint8 *)k;
+    switch(length)
+    {
+    case 12: c+=k[4]+(((quint32)k[5])<<16);
+             b+=k[2]+(((quint32)k[3])<<16);
+             a+=k[0]+(((quint32)k[1])<<16);
+             break;
+    case 11: c+=((quint32)k8[10])<<16;     /* fall through */
+    case 10: c+=k[4];
+             b+=k[2]+(((quint32)k[3])<<16);
+             a+=k[0]+(((quint32)k[1])<<16);
+             break;
+    case 9 : c+=k8[8];                      /* fall through */
+    case 8 : b+=k[2]+(((quint32)k[3])<<16);
+             a+=k[0]+(((quint32)k[1])<<16);
+             break;
+    case 7 : b+=((quint32)k8[6])<<16;      /* fall through */
+    case 6 : b+=k[2];
+             a+=k[0]+(((quint32)k[1])<<16);
+             break;
+    case 5 : b+=k8[4];                      /* fall through */
+    case 4 : a+=k[0]+(((quint32)k[1])<<16);
+             break;
+    case 3 : a+=((quint32)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 quint8 *k = (const quint8 *)key;
+
+    /*--------------- all but the last block: affect some 32 bits of (a,b,c) */
+    while (length > 12)
+    {
+      a += k[0];
+      a += ((quint32)k[1])<<8;
+      a += ((quint32)k[2])<<16;
+      a += ((quint32)k[3])<<24;
+      b += k[4];
+      b += ((quint32)k[5])<<8;
+      b += ((quint32)k[6])<<16;
+      b += ((quint32)k[7])<<24;
+      c += k[8];
+      c += ((quint32)k[9])<<8;
+      c += ((quint32)k[10])<<16;
+      c += ((quint32)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+=((quint32)k[11])<<24;
+    case 11: c+=((quint32)k[10])<<16;
+    case 10: c+=((quint32)k[9])<<8;
+    case 9 : c+=k[8];
+    case 8 : b+=((quint32)k[7])<<24;
+    case 7 : b+=((quint32)k[6])<<16;
+    case 6 : b+=((quint32)k[5])<<8;
+    case 5 : b+=k[4];
+    case 4 : a+=((quint32)k[3])<<24;
+    case 3 : a+=((quint32)k[2])<<16;
+    case 2 : a+=((quint32)k[1])<<8;
+    case 1 : a+=k[0];
+             break;
+    case 0 : return c;
+    }
+  }
+
+  final(a,b,c);
+  return c;
+}
+
+
+/*
+ * hashlittle2: return 2 32-bit hash values
+ *
+ * This is identical to hashlittle(), except it returns two 32-bit hash
+ * values instead of just one.  This is good enough for hash table
+ * lookup with 2^^64 buckets, or if you want a second hash if you're not
+ * happy with the first, or if you want a probably-unique 64-bit ID for
+ * the key.  *pc is better mixed than *pb, so use *pc first.  If you want
+ * a 64-bit value do something like "*pc + (((uint64_t)*pb)<<32)".
+ */
+void hashlittle2( 
+  const void *key,       /* the key to hash */
+  size_t      length,    /* length of the key */
+  quint32   *pc,        /* IN: primary initval, OUT: primary hash */
+  quint32   *pb)        /* IN: secondary initval, OUT: secondary hash */
+{
+  quint32 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 + ((quint32)length) + *pc;
+  c += *pb;
+
+  u.ptr = key;
+  if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
+    const quint32 *k = (const quint32 *)key;         /* read 32-bit 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 */
+
+    const quint8  *k8 = (const quint8 *)k;
+    switch(length)
+    {
+    case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
+    case 11: c+=((quint32)k8[10])<<16;  /* fall through */
+    case 10: c+=((quint32)k8[9])<<8;    /* fall through */
+    case 9 : c+=k8[8];                   /* fall through */
+    case 8 : b+=k[1]; a+=k[0]; break;
+    case 7 : b+=((quint32)k8[6])<<16;   /* fall through */
+    case 6 : b+=((quint32)k8[5])<<8;    /* fall through */
+    case 5 : b+=k8[4];                   /* fall through */
+    case 4 : a+=k[0]; break;
+    case 3 : a+=((quint32)k8[2])<<16;   /* fall through */
+    case 2 : a+=((quint32)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 quint16 *k = (const quint16 *)key;         /* read 16-bit chunks */
+    const quint8  *k8;
+
+    /*--------------- all but last block: aligned reads and different mixing */
+    while (length > 12)
+    {
+      a += k[0] + (((quint32)k[1])<<16);
+      b += k[2] + (((quint32)k[3])<<16);
+      c += k[4] + (((quint32)k[5])<<16);
+      mix(a,b,c);
+      length -= 12;
+      k += 6;
+    }
+
+    /*----------------------------- handle the last (probably partial) block */
+    k8 = (const quint8 *)k;
+    switch(length)
+    {
+    case 12: c+=k[4]+(((quint32)k[5])<<16);
+             b+=k[2]+(((quint32)k[3])<<16);
+             a+=k[0]+(((quint32)k[1])<<16);
+             break;
+    case 11: c+=((quint32)k8[10])<<16;     /* fall through */
+    case 10: c+=k[4];
+             b+=k[2]+(((quint32)k[3])<<16);
+             a+=k[0]+(((quint32)k[1])<<16);
+             break;
+    case 9 : c+=k8[8];                      /* fall through */
+    case 8 : b+=k[2]+(((quint32)k[3])<<16);
+             a+=k[0]+(((quint32)k[1])<<16);
+             break;
+    case 7 : b+=((quint32)k8[6])<<16;      /* fall through */
+    case 6 : b+=k[2];
+             a+=k[0]+(((quint32)k[1])<<16);
+             break;
+    case 5 : b+=k8[4];                      /* fall through */
+    case 4 : a+=k[0]+(((quint32)k[1])<<16);
+             break;
+    case 3 : a+=((quint32)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 quint8 *k = (const quint8 *)key;
+
+    /*--------------- all but the last block: affect some 32 bits of (a,b,c) */
+    while (length > 12)
+    {
+      a += k[0];
+      a += ((quint32)k[1])<<8;
+      a += ((quint32)k[2])<<16;
+      a += ((quint32)k[3])<<24;
+      b += k[4];
+      b += ((quint32)k[5])<<8;
+      b += ((quint32)k[6])<<16;
+      b += ((quint32)k[7])<<24;
+      c += k[8];
+      c += ((quint32)k[9])<<8;
+      c += ((quint32)k[10])<<16;
+      c += ((quint32)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+=((quint32)k[11])<<24;
+    case 11: c+=((quint32)k[10])<<16;
+    case 10: c+=((quint32)k[9])<<8;
+    case 9 : c+=k[8];
+    case 8 : b+=((quint32)k[7])<<24;
+    case 7 : b+=((quint32)k[6])<<16;
+    case 6 : b+=((quint32)k[5])<<8;
+    case 5 : b+=k[4];
+    case 4 : a+=((quint32)k[3])<<24;
+    case 3 : a+=((quint32)k[2])<<16;
+    case 2 : a+=((quint32)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. 
+ */
+quint32 hashbig( const void *key, size_t length, quint32 initval)
+{
+  quint32 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 + ((quint32)length) + initval;
+
+  u.ptr = key;
+  if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) {
+    const quint32 *k = (const quint32 *)key;         /* read 32-bit 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]<<8" actually reads beyond the end of the string, but
+     * then shifts out the part it's not allowed to read.  Because the
+     * string is aligned, the illegal read is in the same word as the
+     * rest of the string.  Every machine with memory protection I've seen
+     * does it on word boundaries, so is OK with this.  But VALGRIND will
+     * still catch it and complain.  The masking trick does make the hash
+     * noticably faster for short strings (like English words).
+     */
+#ifndef VALGRIND
+
+    switch(length)
+    {
+    case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
+    case 11: c+=k[2]&0xffffff00; b+=k[1]; a+=k[0]; break;
+    case 10: c+=k[2]&0xffff0000; b+=k[1]; a+=k[0]; break;
+    case 9 : c+=k[2]&0xff000000; b+=k[1]; a+=k[0]; break;
+    case 8 : b+=k[1]; a+=k[0]; break;
+    case 7 : b+=k[1]&0xffffff00; a+=k[0]; break;
+    case 6 : b+=k[1]&0xffff0000; a+=k[0]; break;
+    case 5 : b+=k[1]&0xff000000; a+=k[0]; break;
+    case 4 : a+=k[0]; break;
+    case 3 : a+=k[0]&0xffffff00; break;
+    case 2 : a+=k[0]&0xffff0000; break;
+    case 1 : a+=k[0]&0xff000000; break;
+    case 0 : return c;              /* zero length strings require no mixing */
+    }
+
+#else  /* make valgrind happy */
+
+    const quint8 *k8 = (const quint8 *)k;
+    switch(length)                   /* all the case statements fall through */
+    {
+    case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
+    case 11: c+=((quint32)k8[10])<<8;  /* fall through */
+    case 10: c+=((quint32)k8[9])<<16;  /* fall through */
+    case 9 : c+=((quint32)k8[8])<<24;  /* fall through */
+    case 8 : b+=k[1]; a+=k[0]; break;
+    case 7 : b+=((quint32)k8[6])<<8;   /* fall through */
+    case 6 : b+=((quint32)k8[5])<<16;  /* fall through */
+    case 5 : b+=((quint32)k8[4])<<24;  /* fall through */
+    case 4 : a+=k[0]; break;
+    case 3 : a+=((quint32)k8[2])<<8;   /* fall through */
+    case 2 : a+=((quint32)k8[1])<<16;  /* fall through */
+    case 1 : a+=((quint32)k8[0])<<24; break;
+    case 0 : return c;
+    }
+
+#endif /* !VALGRIND */
+
+  } else {                        /* need to read the key one byte at a time */
+    const quint8 *k = (const quint8 *)key;
+
+    /*--------------- all but the last block: affect some 32 bits of (a,b,c) */
+    while (length > 12)
+    {
+      a += ((quint32)k[0])<<24;
+      a += ((quint32)k[1])<<16;
+      a += ((quint32)k[2])<<8;
+      a += ((quint32)k[3]);
+      b += ((quint32)k[4])<<24;
+      b += ((quint32)k[5])<<16;
+      b += ((quint32)k[6])<<8;
+      b += ((quint32)k[7]);
+      c += ((quint32)k[8])<<24;
+      c += ((quint32)k[9])<<16;
+      c += ((quint32)k[10])<<8;
+      c += ((quint32)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+=((quint32)k[10])<<8;
+    case 10: c+=((quint32)k[9])<<16;
+    case 9 : c+=((quint32)k[8])<<24;
+    case 8 : b+=k[7];
+    case 7 : b+=((quint32)k[6])<<8;
+    case 6 : b+=((quint32)k[5])<<16;
+    case 5 : b+=((quint32)k[4])<<24;
+    case 4 : a+=k[3];
+    case 3 : a+=((quint32)k[2])<<8;
+    case 2 : a+=((quint32)k[1])<<16;
+    case 1 : a+=((quint32)k[0])<<24;
+             break;
+    case 0 : return c;
+    }
+  }
+
+  final(a,b,c);
+  return c;
+}