Z3 sources

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

lib/hash.cpp

@@ -0,0 +1,85 @@
+/*++
+Copyright (c) 2006 Microsoft Corporation
+
+Module Name:
+
+    hash.cpp
+
+Abstract:
+
+    Basic hash computation support.
+
+Author:
+
+    Leonardo de Moura (leonardo) 2006-09-11.
+
+Revision History:
+
+--*/
+
+#include"debug.h"
+#include"hash.h"
+
+// I'm using Bob Jenkin's hash function.
+// http://burtleburtle.net/bob/hash/doobs.html
+unsigned string_hash(const char * str, unsigned length, unsigned init_value) {
+    register unsigned a, b, c, len;
+
+    /* Set up the internal state */
+    len = length;
+    a = b = 0x9e3779b9;  /* the golden ratio; an arbitrary value */
+    c = init_value;      /* the previous hash value */
+
+    /*---------------------------------------- handle most of the key */
+    while (len >= 12) {
+        a += reinterpret_cast<const unsigned *>(str)[0];
+        b += reinterpret_cast<const unsigned *>(str)[1];
+        c += reinterpret_cast<const unsigned *>(str)[2];
+        mix(a,b,c);
+        str += 12; len -= 12;
+    }
+
+    /*------------------------------------- handle the last 11 bytes */
+    c += length;
+    switch(len) {        /* all the case statements fall through */
+    case 11: 
+        c+=((unsigned)str[10]<<24);
+        __fallthrough;
+    case 10: 
+        c+=((unsigned)str[9]<<16);
+        __fallthrough;
+    case 9 : 
+        c+=((unsigned)str[8]<<8);
+        __fallthrough;
+        /* the first byte of c is reserved for the length */
+    case 8 : 
+        b+=((unsigned)str[7]<<24);
+        __fallthrough;
+    case 7 : 
+        b+=((unsigned)str[6]<<16);
+        __fallthrough;
+    case 6 : 
+        b+=((unsigned)str[5]<<8);
+        __fallthrough;
+    case 5 : 
+        b+=str[4];
+        __fallthrough;
+    case 4 : 
+        a+=((unsigned)str[3]<<24);
+        __fallthrough;
+    case 3 : 
+        a+=((unsigned)str[2]<<16);
+        __fallthrough;
+    case 2 : 
+        a+=((unsigned)str[1]<<8);
+        __fallthrough;
+    case 1 : 
+        a+=str[0];
+        __fallthrough;
+        /* case 0: nothing left to add */
+    }
+    mix(a,b,c);
+    /*-------------------------------------------- report the result */
+    return c;
+}
+