Use epicsStrHash()

src/libCom/cxxTemplates/resourceLib.cpp

@@ -3,8 +3,7 @@
 *     National Laboratory.
 * Copyright (c) 2002 The Regents of the University of California, as
 *     Operator of Los Alamos National Laboratory.
-* EPICS BASE Versions 3.13.7
-* and higher are distributed subject to a Software License Agreement found
+* EPICS BASE is distributed subject to a Software License Agreement found
 * in file LICENSE that is included with this distribution. 
 \*************************************************************************/
 

src/libCom/cxxTemplates/resourceLib.h

@@ -3,8 +3,7 @@
 *     National Laboratory.
 * Copyright (c) 2002 The Regents of the University of California, as
 *     Operator of Los Alamos National Laboratory.
-* EPICS BASE Versions 3.13.7
-* and higher are distributed subject to a Software License Agreement found
+* EPICS BASE is distributed subject to a Software License Agreement found
 * in file LICENSE that is included with this distribution. 
 \*************************************************************************/
 /*
@@ -43,6 +42,7 @@
 #endif
 
 #include "tsSLList.h"
+#include "epicsString.h"
 #include "shareLib.h"
 typedef size_t resTableIndex;
 
@@ -269,7 +269,6 @@ private:
     stringId ( const stringId &);
     const char * pStr;
     const allocationType allocType;
-    static const unsigned char fastHashPermutedIndexSpace[256];
 };
 
 /////////////////////////////////////////////////
@@ -397,6 +396,7 @@ void resTable<T,ID>::show ( unsigned level ) const
         double X = 0.0;
         double XX = 0.0;
         unsigned maxEntries = 0u;
+        unsigned empty = 0;
         for ( unsigned i = 0u; i < N; i++ ) {
             tsSLIter<T> pItem = this->pTable[i].firstIter ();
             unsigned count = 0;
@@ -413,14 +413,16 @@ void resTable<T,ID>::show ( unsigned level ) const
                 if ( count > maxEntries ) {
                     maxEntries = count;
                 }
-            }
+            } else
+                empty++;
         }
-     
+
         double mean = X / N;
         double stdDev = sqrt( XX / N - mean * mean );
         printf ( 
-    "entries per bucket: mean = %f std dev = %f max = %d\n",
+    "entries per bucket: mean = %f std dev = %f max = %u\n",
             mean, stdDev, maxEntries );
+        printf("%u empty buckets\n", empty);
         if ( X != this->nInUse ) {
             printf ("this->nInUse didnt match items counted which was %f????\n", X );
         }
@@ -1156,86 +1158,14 @@ stringId::~stringId()
 //
 // stringId::hash()
 //
-// This is a modification of the algorithm described in 
-// "Fast Hashing of Variable Length Text Strings", Peter K. Pearson, 
-// Communications of the ACM, June 1990. The initial modifications 
-// were designed by Marty Kraimer. Some additional minor optimizations
-// by Jeff Hill.
-//
 resTableIndex stringId::hash() const
 {
-    const unsigned stringIdMinIndexWidth = CHAR_BIT;
-    const unsigned stringIdMaxIndexWidth = CHAR_BIT * sizeof ( unsigned );
-    const unsigned char *pUStr = 
-        reinterpret_cast < const unsigned char * > ( this->pStr );
-
-    if ( ! pUStr ) {
+    if (!this->pStr) {
         return 0u;
     }
-
-    unsigned h0 = 0;
-    unsigned h1 = 0;
-    unsigned h2 = 0;
-    unsigned h3 = 0;
-    unsigned c;
-
-    while ( true ) {
-
-        c = * ( pUStr++ );
-        if ( c == 0 ) {
-            break;
-        }
-        h0 = fastHashPermutedIndexSpace [ h0 ^ c ];
-
-        c = * ( pUStr++ );
-        if ( c == 0 ) {
-            break;
-        }
-        h1 = fastHashPermutedIndexSpace [ h1 ^ c ];
-
-        c = * ( pUStr++ );
-        if ( c == 0 ) {
-            break;
-        }
-        h2 = fastHashPermutedIndexSpace [ h2 ^ c ];
-
-        c = * ( pUStr++ );
-        if ( c == 0 ) {
-            break;
-        }
-        h3 = fastHashPermutedIndexSpace [ h3 ^ c ];
-    }
-
-    h0 = ( h3 << 24 ) | ( h2 << 16 ) | ( h1 << 8 ) | h0;
-
-    return integerHash ( stringIdMinIndexWidth, stringIdMaxIndexWidth, h0 );
+    return epicsStrHash(this->pStr, 0);
 }
 
-//
-// This is a modification of the algorithm described in
-// "Fast Hashing of Variable Length Text Strings", Peter K. 
-// Pearson, Communications of the ACM, June 1990
-// The modifications were designed by Marty Kraimer
-//
-const unsigned char stringId::fastHashPermutedIndexSpace[256] = {
- 39,159,180,252, 71,  6, 13,164,232, 35,226,155, 98,120,154, 69,
-157, 24,137, 29,147, 78,121, 85,112,  8,248,130, 55,117,190,160,
-176,131,228, 64,211,106, 38, 27,140, 30, 88,210,227,104, 84, 77,
- 75,107,169,138,195,184, 70, 90, 61,166,  7,244,165,108,219, 51,
-  9,139,209, 40, 31,202, 58,179,116, 33,207,146, 76, 60,242,124,
-254,197, 80,167,153,145,129,233,132, 48,246, 86,156,177, 36,187,
- 45,  1, 96, 18, 19, 62,185,234, 99, 16,218, 95,128,224,123,253,
- 42,109,  4,247, 72,  5,151,136,  0,152,148,127,204,133, 17, 14,
-182,217, 54,199,119,174, 82, 57,215, 41,114,208,206,110,239, 23,
-189, 15,  3, 22,188, 79,113,172, 28,  2,222, 21,251,225,237,105,
-102, 32, 56,181,126, 83,230, 53,158, 52, 59,213,118,100, 67,142,
-220,170,144,115,205, 26,125,168,249, 66,175, 97,255, 92,229, 91,
-214,236,178,243, 46, 44,201,250,135,186,150,221,163,216,162, 43,
- 11,101, 34, 37,194, 25, 50, 12, 87,198,173,240,193,171,143,231,
-111,141,191,103, 74,245,223, 20,161,235,122, 63, 89,149, 73,238,
-134, 68, 93,183,241, 81,196, 49,192, 65,212, 94,203, 10,200, 47
-};
-
 #endif // if instantiateRecourceLib is defined
 
 #endif // INCresourceLibh