1/* This file is part of the Variable::Magic Perl module.
2 * See http://search.cpan.org/dist/Variable-Magic/ */
3
4/* This is a pointer table implementation essentially copied from the ptr_table
5 * implementation in perl's sv.c, except that it has been modified to use memory
6 * shared across threads.
7 * Copyright goes to the original authors, bug reports to me. */
8
9/* This header is designed to be included several times with different
10 * definitions for PTABLE_NAME and PTABLE_VAL_FREE(). */
11
12#undef VOID2
13#ifdef __cplusplus
14# define VOID2(T, P) static_cast<T>(P)
15#else
16# define VOID2(T, P) (P)
17#endif
18
19#undef pPTBLMS
20#undef pPTBLMS_
21#undef aPTBLMS
22#undef aPTBLMS_
23
24/* Context for PerlMemShared_* functions */
25
26#ifdef PERL_IMPLICIT_SYS
27# define pPTBLMS  pTHX
28# define pPTBLMS_ pTHX_
29# define aPTBLMS  aTHX
30# define aPTBLMS_ aTHX_
31#else
32# define pPTBLMS  void
33# define pPTBLMS_
34# define aPTBLMS
35# define aPTBLMS_
36#endif
37
38#ifndef pPTBL
39# define pPTBL  pPTBLMS
40#endif
41#ifndef pPTBL_
42# define pPTBL_ pPTBLMS_
43#endif
44#ifndef aPTBL
45# define aPTBL  aPTBLMS
46#endif
47#ifndef aPTBL_
48# define aPTBL_ aPTBLMS_
49#endif
50
51#ifndef PTABLE_NAME
52# define PTABLE_NAME ptable
53#endif
54
55#ifndef PTABLE_VAL_FREE
56# define PTABLE_VAL_FREE(V)
57#endif
58
59#ifndef PTABLE_JOIN
60# define PTABLE_PASTE(A, B) A ## B
61# define PTABLE_JOIN(A, B)  PTABLE_PASTE(A, B)
62#endif
63
64#ifndef PTABLE_PREFIX
65# define PTABLE_PREFIX(X) PTABLE_JOIN(PTABLE_NAME, X)
66#endif
67
68#ifndef ptable_ent
69typedef struct ptable_ent {
70 struct ptable_ent *next;
71 const void *       key;
72 void *             val;
73} ptable_ent;
74#define ptable_ent ptable_ent
75#endif /* !ptable_ent */
76
77#ifndef ptable
78typedef struct ptable {
79 ptable_ent **ary;
80 size_t       max;
81 size_t       items;
82} ptable;
83#define ptable ptable
84#endif /* !ptable */
85
86#ifndef ptable_new
87STATIC ptable *ptable_new(pPTBLMS) {
88#define ptable_new() ptable_new(aPTBLMS)
89 ptable *t = VOID2(ptable *, PerlMemShared_malloc(sizeof *t));
90 t->max    = 15;
91 t->items  = 0;
92 t->ary    = VOID2(ptable_ent **,
93                              PerlMemShared_calloc(t->max + 1, sizeof *t->ary));
94 return t;
95}
96#endif /* !ptable_new */
97
98#ifndef PTABLE_HASH
99# define PTABLE_HASH(ptr) \
100     ((PTR2UV(ptr) >> 3) ^ (PTR2UV(ptr) >> (3 + 7)) ^ (PTR2UV(ptr) >> (3 + 17)))
101#endif
102
103#ifndef ptable_find
104STATIC ptable_ent *ptable_find(const ptable * const t, const void * const key) {
105#define ptable_find ptable_find
106 ptable_ent *ent;
107 const UV hash = PTABLE_HASH(key);
108
109 ent = t->ary[hash & t->max];
110 for (; ent; ent = ent->next) {
111  if (ent->key == key)
112   return ent;
113 }
114
115 return NULL;
116}
117#endif /* !ptable_find */
118
119#ifndef ptable_fetch
120STATIC void *ptable_fetch(const ptable * const t, const void * const key) {
121#define ptable_fetch ptable_fetch
122 const ptable_ent *const ent = ptable_find(t, key);
123
124 return ent ? ent->val : NULL;
125}
126#endif /* !ptable_fetch */
127
128#ifndef ptable_split
129STATIC void ptable_split(pPTBLMS_ ptable * const t) {
130#define ptable_split(T) ptable_split(aPTBLMS_ (T))
131 ptable_ent **ary = t->ary;
132 const size_t oldsize = t->max + 1;
133 size_t newsize = oldsize * 2;
134 size_t i;
135
136 ary = VOID2(ptable_ent **, PerlMemShared_realloc(ary, newsize * sizeof(*ary)));
137 Zero(&ary[oldsize], newsize - oldsize, sizeof(*ary));
138 t->max = --newsize;
139 t->ary = ary;
140
141 for (i = 0; i < oldsize; i++, ary++) {
142  ptable_ent **curentp, **entp, *ent;
143  if (!*ary)
144   continue;
145  curentp = ary + oldsize;
146  for (entp = ary, ent = *ary; ent; ent = *entp) {
147   if ((newsize & PTABLE_HASH(ent->key)) != i) {
148    *entp     = ent->next;
149    ent->next = *curentp;
150    *curentp  = ent;
151    continue;
152   } else
153    entp = &ent->next;
154  }
155 }
156}
157#endif /* !ptable_split */
158
159STATIC void PTABLE_PREFIX(_store)(pPTBL_ ptable * const t, const void * const key, void * const val) {
160 ptable_ent *ent = ptable_find(t, key);
161
162 if (ent) {
163  void *oldval = ent->val;
164  PTABLE_VAL_FREE(oldval);
165  ent->val = val;
166 } else if (val) {
167  const size_t i = PTABLE_HASH(key) & t->max;
168  ent = VOID2(ptable_ent *, PerlMemShared_malloc(sizeof *ent));
169  ent->key  = key;
170  ent->val  = val;
171  ent->next = t->ary[i];
172  t->ary[i] = ent;
173  t->items++;
174  if (ent->next && t->items > t->max)
175   ptable_split(t);
176 }
177}
178
179#ifndef ptable_walk
180STATIC void ptable_walk(pTHX_ ptable * const t, void (*cb)(pTHX_ ptable_ent *ent, void *userdata), void *userdata) {
181#define ptable_walk(T, CB, UD) ptable_walk(aTHX_ (T), (CB), (UD))
182 if (t && t->items) {
183  register ptable_ent ** const array = t->ary;
184  size_t i = t->max;
185  do {
186   ptable_ent *entry;
187   for (entry = array[i]; entry; entry = entry->next)
188    cb(aTHX_ entry, userdata);
189  } while (i--);
190 }
191}
192#endif /* !ptable_walk */
193
194STATIC void PTABLE_PREFIX(_clear)(pPTBL_ ptable * const t) {
195 if (t && t->items) {
196  register ptable_ent ** const array = t->ary;
197  size_t i = t->max;
198
199  do {
200   ptable_ent *entry = array[i];
201   while (entry) {
202    ptable_ent * const oentry = entry;
203    void *val = oentry->val;
204    entry = entry->next;
205    PTABLE_VAL_FREE(val);
206    PerlMemShared_free(oentry);
207   }
208   array[i] = NULL;
209  } while (i--);
210
211  t->items = 0;
212 }
213}
214
215STATIC void PTABLE_PREFIX(_free)(pPTBL_ ptable * const t) {
216 if (!t)
217  return;
218 PTABLE_PREFIX(_clear)(aPTBL_ t);
219 PerlMemShared_free(t->ary);
220 PerlMemShared_free(t);
221}
222
223#undef pPTBL
224#undef pPTBL_
225#undef aPTBL
226#undef aPTBL_
227
228#undef PTABLE_NAME
229#undef PTABLE_VAL_FREE
230