src/common/hashmap.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/common/hashmap.cpp
   3 // Purpose:     wxHashMap implementation
   4 // Author:      Mattia Barbon
   5 // Modified by:
   6 // Created:     29/01/2002
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Mattia Barbon
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // For compilers that support precompilation, includes "wx.h".
  13 #include "wx/wxprec.h"
  14
  15 #ifdef __BORLANDC__
  16     #pragma hdrstop
  17 #endif
  18
  19 #include "wx/hashmap.h"
  20
  21 /* FYI: This is the "One-at-a-Time" algorithm by Bob Jenkins */
  22 /* from requirements by Colin Plumb. */
  23 /* (http://burtleburtle.net/bob/hash/doobs.html) */
  24 /* adapted from Perl sources ( hv.h ) */
  25 template<typename T>
  26 static unsigned long DoStringHash(T *k)
  27 {
  28     unsigned long hash = 0;
  29
  30     while( *k )
  31     {
  32         hash += *k++;
  33         hash += (hash << 10);
  34         hash ^= (hash >> 6);
  35     }
  36     hash += (hash << 3);
  37     hash ^= (hash >> 11);
  38
  39     return hash + (hash << 15);
  40 }
  41
  42 unsigned long wxStringHash::stringHash( const char* k )
  43   { return DoStringHash(k); }
  44
  45 unsigned long wxStringHash::stringHash( const wchar_t* k )
  46   { return DoStringHash(k); }
  47
  48
  49 #if !wxUSE_STL || !defined(HAVE_STL_HASH_MAP)
  50
  51 /* from SGI STL */
  52 const unsigned long _wxHashTableBase2::ms_primes[prime_count] =
  53 {
  54     7ul,          13ul,         29ul,
  55     53ul,         97ul,         193ul,       389ul,       769ul,
  56     1543ul,       3079ul,       6151ul,      12289ul,     24593ul,
  57     49157ul,      98317ul,      196613ul,    393241ul,    786433ul,
  58     1572869ul,    3145739ul,    6291469ul,   12582917ul,  25165843ul,
  59     50331653ul,   100663319ul,  201326611ul, 402653189ul, 805306457ul,
  60     1610612741ul, 3221225473ul, 4294967291ul
  61 };
  62
  63 unsigned long _wxHashTableBase2::GetNextPrime( unsigned long n )
  64 {
  65     const unsigned long* ptr = &ms_primes[0];
  66     for( size_t i = 0; i < prime_count; ++i, ++ptr )
  67     {
  68         if( n < *ptr )
  69             return *ptr;
  70     }
  71
  72     /* someone might try to alloc a 2^32-element hash table */
  73     wxFAIL_MSG( _T("hash table too big?") );
  74
  75     /* quiet warning */
  76     return 0;
  77 }
  78
  79 unsigned long _wxHashTableBase2::GetPreviousPrime( unsigned long n )
  80 {
  81     const unsigned long* ptr = &ms_primes[prime_count - 1];
  82
  83     for( size_t i = 0; i < prime_count; ++i, --ptr )
  84     {
  85         if( n > *ptr )
  86             return *ptr;
  87     }
  88
  89     /* quiet warning */
  90     return 1;
  91 }
  92
  93 void _wxHashTableBase2::DeleteNodes( size_t buckets,
  94                                      _wxHashTable_NodeBase** table,
  95                                      NodeDtor dtor )
  96 {
  97     size_t i;
  98
  99     for( i = 0; i < buckets; ++i )
 100     {
 101         _wxHashTable_NodeBase* node = table[i];
 102         _wxHashTable_NodeBase* tmp;
 103
 104         while( node )
 105         {
 106             tmp = node->m_nxt;
 107             dtor( node );
 108             node = tmp;
 109         }
 110     }
 111
 112     memset( table, 0, buckets * sizeof(void*) );
 113 }
 114
 115 void _wxHashTableBase2::CopyHashTable( _wxHashTable_NodeBase** srcTable,
 116                                        size_t srcBuckets,
 117                                        _wxHashTableBase2* dst,
 118                                        _wxHashTable_NodeBase** dstTable,
 119                                        BucketFromNode func, ProcessNode proc )
 120 {
 121     for( size_t i = 0; i < srcBuckets; ++i )
 122     {
 123         _wxHashTable_NodeBase* nextnode;
 124
 125         for( _wxHashTable_NodeBase* node = srcTable[i]; node; node = nextnode )
 126         {
 127             size_t bucket = func( dst, node );
 128
 129             nextnode = node->m_nxt;
 130             _wxHashTable_NodeBase* newnode = proc( node );
 131             newnode->m_nxt = dstTable[bucket];
 132             dstTable[bucket] = newnode;
 133         }
 134     }
 135 }
 136
 137 _wxHashTable_NodeBase* _wxHashTableBase2::DummyProcessNode(_wxHashTable_NodeBase* node)
 138 {
 139     return node;
 140 }
 141
 142 #endif // !wxUSE_STL || !defined(HAVE_STL_HASH_MAP)