1/*
2** 2008 September 1
3**
4** The author disclaims copyright to this source code.  In place of
5** a legal notice, here is a blessing:
6**
7**    May you do good and not evil.
8**    May you find forgiveness for yourself and forgive others.
9**    May you share freely, never taking more than you give.
10**
11*************************************************************************
12**
13** The code in this file contains sample implementations of the
14** sqlite3_wsd_init() and sqlite3_wsd_find() functions required if the
15** SQLITE_OMIT_WSD symbol is defined at build time.
16*/
17
18#if defined(SQLITE_OMIT_WSD) && defined(SQLITE_TEST)
19
20#include "sqliteInt.h"
21
22#define PLS_HASHSIZE 43
23
24typedef struct ProcessLocalStorage ProcessLocalStorage;
25typedef struct ProcessLocalVar ProcessLocalVar;
26
27struct ProcessLocalStorage {
28  ProcessLocalVar *aData[PLS_HASHSIZE];
29  int nFree;
30  u8 *pFree;
31};
32
33struct ProcessLocalVar {
34  void *pKey;
35  ProcessLocalVar *pNext;
36};
37
38static ProcessLocalStorage *pGlobal = 0;
39
40int sqlite3_wsd_init(int N, int J){
41  if( !pGlobal ){
42    int nMalloc = N + sizeof(ProcessLocalStorage) + J*sizeof(ProcessLocalVar);
43    pGlobal = (ProcessLocalStorage *)malloc(nMalloc);
44    if( pGlobal ){
45      memset(pGlobal, 0, sizeof(ProcessLocalStorage));
46      pGlobal->nFree = nMalloc - sizeof(ProcessLocalStorage);
47      pGlobal->pFree = (u8 *)&pGlobal[1];
48    }
49  }
50
51  return pGlobal ? SQLITE_OK : SQLITE_NOMEM;
52}
53
54void *sqlite3_wsd_find(void *K, int L){
55  int i;
56  int iHash = 0;
57  ProcessLocalVar *pVar;
58
59  /* Calculate a hash of K */
60  for(i=0; i<sizeof(void*); i++){
61    iHash = (iHash<<3) + ((unsigned char *)&K)[i];
62  }
63  iHash = iHash%PLS_HASHSIZE;
64
65  /* Search the hash table for K. */
66  for(pVar=pGlobal->aData[iHash]; pVar && pVar->pKey!=K; pVar=pVar->pNext);
67
68  /* If no entry for K was found, create and populate a new one. */
69  if( !pVar ){
70    int nByte = ROUND8(sizeof(ProcessLocalVar) + L);
71    assert( pGlobal->nFree>=nByte );
72    pVar = (ProcessLocalVar *)pGlobal->pFree;
73    pVar->pKey = K;
74    pVar->pNext = pGlobal->aData[iHash];
75    pGlobal->aData[iHash] = pVar;
76    pGlobal->nFree -= nByte;
77    pGlobal->pFree += nByte;
78    memcpy(&pVar[1], K, L);
79  }
80
81  return (void *)&pVar[1];
82}
83
84#endif
85