|
1866
|
1 /*
|
|
|
2 ** $Id: ltable.c,v 2.72 2012/09/11 19:37:16 roberto Exp $
|
|
|
3 ** Lua tables (hash)
|
|
|
4 ** See Copyright Notice in lua.h
|
|
|
5 */
|
|
|
6
|
|
|
7
|
|
|
8 /*
|
|
|
9 ** Implementation of tables (aka arrays, objects, or hash tables).
|
|
|
10 ** Tables keep its elements in two parts: an array part and a hash part.
|
|
|
11 ** Non-negative integer keys are all candidates to be kept in the array
|
|
|
12 ** part. The actual size of the array is the largest `n' such that at
|
|
|
13 ** least half the slots between 0 and n are in use.
|
|
|
14 ** Hash uses a mix of chained scatter table with Brent's variation.
|
|
|
15 ** A main invariant of these tables is that, if an element is not
|
|
|
16 ** in its main position (i.e. the `original' position that its hash gives
|
|
|
17 ** to it), then the colliding element is in its own main position.
|
|
|
18 ** Hence even when the load factor reaches 100%, performance remains good.
|
|
|
19 */
|
|
|
20
|
|
|
21 #include <string.h>
|
|
|
22
|
|
|
23 #define ltable_c
|
|
|
24 #define LUA_CORE
|
|
|
25
|
|
|
26 #include "lua.h"
|
|
|
27
|
|
|
28 #include "ldebug.h"
|
|
|
29 #include "ldo.h"
|
|
|
30 #include "lgc.h"
|
|
|
31 #include "lmem.h"
|
|
|
32 #include "lobject.h"
|
|
|
33 #include "lstate.h"
|
|
|
34 #include "lstring.h"
|
|
|
35 #include "ltable.h"
|
|
|
36 #include "lvm.h"
|
|
|
37
|
|
|
38
|
|
|
39 /*
|
|
|
40 ** max size of array part is 2^MAXBITS
|
|
|
41 */
|
|
|
42 #if LUAI_BITSINT >= 32
|
|
|
43 #define MAXBITS 30
|
|
|
44 #else
|
|
|
45 #define MAXBITS (LUAI_BITSINT-2)
|
|
|
46 #endif
|
|
|
47
|
|
|
48 #define MAXASIZE (1 << MAXBITS)
|
|
|
49
|
|
|
50
|
|
|
51 #define hashpow2(t,n) (gnode(t, lmod((n), sizenode(t))))
|
|
|
52
|
|
|
53 #define hashstr(t,str) hashpow2(t, (str)->tsv.hash)
|
|
|
54 #define hashboolean(t,p) hashpow2(t, p)
|
|
|
55
|
|
|
56
|
|
|
57 /*
|
|
|
58 ** for some types, it is better to avoid modulus by power of 2, as
|
|
|
59 ** they tend to have many 2 factors.
|
|
|
60 */
|
|
|
61 #define hashmod(t,n) (gnode(t, ((n) % ((sizenode(t)-1)|1))))
|
|
|
62
|
|
|
63
|
|
|
64 #define hashpointer(t,p) hashmod(t, IntPoint(p))
|
|
|
65
|
|
|
66
|
|
|
67 #define dummynode (&dummynode_)
|
|
|
68
|
|
|
69 #define isdummy(n) ((n) == dummynode)
|
|
|
70
|
|
|
71 static const Node dummynode_ = {
|
|
|
72 {NILCONSTANT}, /* value */
|
|
|
73 {{NILCONSTANT, NULL}} /* key */
|
|
|
74 };
|
|
|
75
|
|
|
76
|
|
|
77 /*
|
|
|
78 ** hash for lua_Numbers
|
|
|
79 */
|
|
|
80 static Node *hashnum (const Table *t, lua_Number n) {
|
|
|
81 int i;
|
|
|
82 luai_hashnum(i, n);
|
|
|
83 if (i < 0) {
|
|
|
84 if (cast(unsigned int, i) == 0u - i) /* use unsigned to avoid overflows */
|
|
|
85 i = 0; /* handle INT_MIN */
|
|
|
86 i = -i; /* must be a positive value */
|
|
|
87 }
|
|
|
88 return hashmod(t, i);
|
|
|
89 }
|
|
|
90
|
|
|
91
|
|
|
92
|
|
|
93 /*
|
|
|
94 ** returns the `main' position of an element in a table (that is, the index
|
|
|
95 ** of its hash value)
|
|
|
96 */
|
|
|
97 static Node *mainposition (const Table *t, const TValue *key) {
|
|
|
98 switch (ttype(key)) {
|
|
|
99 case LUA_TNUMBER:
|
|
|
100 return hashnum(t, nvalue(key));
|
|
|
101 case LUA_TLNGSTR: {
|
|
|
102 TString *s = rawtsvalue(key);
|
|
|
103 if (s->tsv.extra == 0) { /* no hash? */
|
|
|
104 s->tsv.hash = luaS_hash(getstr(s), s->tsv.len, s->tsv.hash);
|
|
|
105 s->tsv.extra = 1; /* now it has its hash */
|
|
|
106 }
|
|
|
107 return hashstr(t, rawtsvalue(key));
|
|
|
108 }
|
|
|
109 case LUA_TSHRSTR:
|
|
|
110 return hashstr(t, rawtsvalue(key));
|
|
|
111 case LUA_TBOOLEAN:
|
|
|
112 return hashboolean(t, bvalue(key));
|
|
|
113 case LUA_TLIGHTUSERDATA:
|
|
|
114 return hashpointer(t, pvalue(key));
|
|
|
115 case LUA_TLCF:
|
|
|
116 return hashpointer(t, fvalue(key));
|
|
|
117 default:
|
|
|
118 return hashpointer(t, gcvalue(key));
|
|
|
119 }
|
|
|
120 }
|
|
|
121
|
|
|
122
|
|
|
123 /*
|
|
|
124 ** returns the index for `key' if `key' is an appropriate key to live in
|
|
|
125 ** the array part of the table, -1 otherwise.
|
|
|
126 */
|
|
|
127 static int arrayindex (const TValue *key) {
|
|
|
128 if (ttisnumber(key)) {
|
|
|
129 lua_Number n = nvalue(key);
|
|
|
130 int k;
|
|
|
131 lua_number2int(k, n);
|
|
|
132 if (luai_numeq(cast_num(k), n))
|
|
|
133 return k;
|
|
|
134 }
|
|
|
135 return -1; /* `key' did not match some condition */
|
|
|
136 }
|
|
|
137
|
|
|
138
|
|
|
139 /*
|
|
|
140 ** returns the index of a `key' for table traversals. First goes all
|
|
|
141 ** elements in the array part, then elements in the hash part. The
|
|
|
142 ** beginning of a traversal is signaled by -1.
|
|
|
143 */
|
|
|
144 static int findindex (lua_State *L, Table *t, StkId key) {
|
|
|
145 int i;
|
|
|
146 if (ttisnil(key)) return -1; /* first iteration */
|
|
|
147 i = arrayindex(key);
|
|
|
148 if (0 < i && i <= t->sizearray) /* is `key' inside array part? */
|
|
|
149 return i-1; /* yes; that's the index (corrected to C) */
|
|
|
150 else {
|
|
|
151 Node *n = mainposition(t, key);
|
|
|
152 for (;;) { /* check whether `key' is somewhere in the chain */
|
|
|
153 /* key may be dead already, but it is ok to use it in `next' */
|
|
|
154 if (luaV_rawequalobj(gkey(n), key) ||
|
|
|
155 (ttisdeadkey(gkey(n)) && iscollectable(key) &&
|
|
|
156 deadvalue(gkey(n)) == gcvalue(key))) {
|
|
|
157 i = cast_int(n - gnode(t, 0)); /* key index in hash table */
|
|
|
158 /* hash elements are numbered after array ones */
|
|
|
159 return i + t->sizearray;
|
|
|
160 }
|
|
|
161 else n = gnext(n);
|
|
|
162 if (n == NULL)
|
|
|
163 luaG_runerror(L, "invalid key to " LUA_QL("next")); /* key not found */
|
|
|
164 }
|
|
|
165 }
|
|
|
166 }
|
|
|
167
|
|
|
168
|
|
|
169 int luaH_next (lua_State *L, Table *t, StkId key) {
|
|
|
170 int i = findindex(L, t, key); /* find original element */
|
|
|
171 for (i++; i < t->sizearray; i++) { /* try first array part */
|
|
|
172 if (!ttisnil(&t->array[i])) { /* a non-nil value? */
|
|
|
173 setnvalue(key, cast_num(i+1));
|
|
|
174 setobj2s(L, key+1, &t->array[i]);
|
|
|
175 return 1;
|
|
|
176 }
|
|
|
177 }
|
|
|
178 for (i -= t->sizearray; i < sizenode(t); i++) { /* then hash part */
|
|
|
179 if (!ttisnil(gval(gnode(t, i)))) { /* a non-nil value? */
|
|
|
180 setobj2s(L, key, gkey(gnode(t, i)));
|
|
|
181 setobj2s(L, key+1, gval(gnode(t, i)));
|
|
|
182 return 1;
|
|
|
183 }
|
|
|
184 }
|
|
|
185 return 0; /* no more elements */
|
|
|
186 }
|
|
|
187
|
|
|
188
|
|
|
189 /*
|
|
|
190 ** {=============================================================
|
|
|
191 ** Rehash
|
|
|
192 ** ==============================================================
|
|
|
193 */
|
|
|
194
|
|
|
195
|
|
|
196 static int computesizes (int nums[], int *narray) {
|
|
|
197 int i;
|
|
|
198 int twotoi; /* 2^i */
|
|
|
199 int a = 0; /* number of elements smaller than 2^i */
|
|
|
200 int na = 0; /* number of elements to go to array part */
|
|
|
201 int n = 0; /* optimal size for array part */
|
|
|
202 for (i = 0, twotoi = 1; twotoi/2 < *narray; i++, twotoi *= 2) {
|
|
|
203 if (nums[i] > 0) {
|
|
|
204 a += nums[i];
|
|
|
205 if (a > twotoi/2) { /* more than half elements present? */
|
|
|
206 n = twotoi; /* optimal size (till now) */
|
|
|
207 na = a; /* all elements smaller than n will go to array part */
|
|
|
208 }
|
|
|
209 }
|
|
|
210 if (a == *narray) break; /* all elements already counted */
|
|
|
211 }
|
|
|
212 *narray = n;
|
|
|
213 lua_assert(*narray/2 <= na && na <= *narray);
|
|
|
214 return na;
|
|
|
215 }
|
|
|
216
|
|
|
217
|
|
|
218 static int countint (const TValue *key, int *nums) {
|
|
|
219 int k = arrayindex(key);
|
|
|
220 if (0 < k && k <= MAXASIZE) { /* is `key' an appropriate array index? */
|
|
|
221 nums[luaO_ceillog2(k)]++; /* count as such */
|
|
|
222 return 1;
|
|
|
223 }
|
|
|
224 else
|
|
|
225 return 0;
|
|
|
226 }
|
|
|
227
|
|
|
228
|
|
|
229 static int numusearray (const Table *t, int *nums) {
|
|
|
230 int lg;
|
|
|
231 int ttlg; /* 2^lg */
|
|
|
232 int ause = 0; /* summation of `nums' */
|
|
|
233 int i = 1; /* count to traverse all array keys */
|
|
|
234 for (lg=0, ttlg=1; lg<=MAXBITS; lg++, ttlg*=2) { /* for each slice */
|
|
|
235 int lc = 0; /* counter */
|
|
|
236 int lim = ttlg;
|
|
|
237 if (lim > t->sizearray) {
|
|
|
238 lim = t->sizearray; /* adjust upper limit */
|
|
|
239 if (i > lim)
|
|
|
240 break; /* no more elements to count */
|
|
|
241 }
|
|
|
242 /* count elements in range (2^(lg-1), 2^lg] */
|
|
|
243 for (; i <= lim; i++) {
|
|
|
244 if (!ttisnil(&t->array[i-1]))
|
|
|
245 lc++;
|
|
|
246 }
|
|
|
247 nums[lg] += lc;
|
|
|
248 ause += lc;
|
|
|
249 }
|
|
|
250 return ause;
|
|
|
251 }
|
|
|
252
|
|
|
253
|
|
|
254 static int numusehash (const Table *t, int *nums, int *pnasize) {
|
|
|
255 int totaluse = 0; /* total number of elements */
|
|
|
256 int ause = 0; /* summation of `nums' */
|
|
|
257 int i = sizenode(t);
|
|
|
258 while (i--) {
|
|
|
259 Node *n = &t->node[i];
|
|
|
260 if (!ttisnil(gval(n))) {
|
|
|
261 ause += countint(gkey(n), nums);
|
|
|
262 totaluse++;
|
|
|
263 }
|
|
|
264 }
|
|
|
265 *pnasize += ause;
|
|
|
266 return totaluse;
|
|
|
267 }
|
|
|
268
|
|
|
269
|
|
|
270 static void setarrayvector (lua_State *L, Table *t, int size) {
|
|
|
271 int i;
|
|
|
272 luaM_reallocvector(L, t->array, t->sizearray, size, TValue);
|
|
|
273 for (i=t->sizearray; i<size; i++)
|
|
|
274 setnilvalue(&t->array[i]);
|
|
|
275 t->sizearray = size;
|
|
|
276 }
|
|
|
277
|
|
|
278
|
|
|
279 static void setnodevector (lua_State *L, Table *t, int size) {
|
|
|
280 int lsize;
|
|
|
281 if (size == 0) { /* no elements to hash part? */
|
|
|
282 t->node = cast(Node *, dummynode); /* use common `dummynode' */
|
|
|
283 lsize = 0;
|
|
|
284 }
|
|
|
285 else {
|
|
|
286 int i;
|
|
|
287 lsize = luaO_ceillog2(size);
|
|
|
288 if (lsize > MAXBITS)
|
|
|
289 luaG_runerror(L, "table overflow");
|
|
|
290 size = twoto(lsize);
|
|
|
291 t->node = luaM_newvector(L, size, Node);
|
|
|
292 for (i=0; i<size; i++) {
|
|
|
293 Node *n = gnode(t, i);
|
|
|
294 gnext(n) = NULL;
|
|
|
295 setnilvalue(gkey(n));
|
|
|
296 setnilvalue(gval(n));
|
|
|
297 }
|
|
|
298 }
|
|
|
299 t->lsizenode = cast_byte(lsize);
|
|
|
300 t->lastfree = gnode(t, size); /* all positions are free */
|
|
|
301 }
|
|
|
302
|
|
|
303
|
|
|
304 void luaH_resize (lua_State *L, Table *t, int nasize, int nhsize) {
|
|
|
305 int i;
|
|
|
306 int oldasize = t->sizearray;
|
|
|
307 int oldhsize = t->lsizenode;
|
|
|
308 Node *nold = t->node; /* save old hash ... */
|
|
|
309 if (nasize > oldasize) /* array part must grow? */
|
|
|
310 setarrayvector(L, t, nasize);
|
|
|
311 /* create new hash part with appropriate size */
|
|
|
312 setnodevector(L, t, nhsize);
|
|
|
313 if (nasize < oldasize) { /* array part must shrink? */
|
|
|
314 t->sizearray = nasize;
|
|
|
315 /* re-insert elements from vanishing slice */
|
|
|
316 for (i=nasize; i<oldasize; i++) {
|
|
|
317 if (!ttisnil(&t->array[i]))
|
|
|
318 luaH_setint(L, t, i + 1, &t->array[i]);
|
|
|
319 }
|
|
|
320 /* shrink array */
|
|
|
321 luaM_reallocvector(L, t->array, oldasize, nasize, TValue);
|
|
|
322 }
|
|
|
323 /* re-insert elements from hash part */
|
|
|
324 for (i = twoto(oldhsize) - 1; i >= 0; i--) {
|
|
|
325 Node *old = nold+i;
|
|
|
326 if (!ttisnil(gval(old))) {
|
|
|
327 /* doesn't need barrier/invalidate cache, as entry was
|
|
|
328 already present in the table */
|
|
|
329 setobjt2t(L, luaH_set(L, t, gkey(old)), gval(old));
|
|
|
330 }
|
|
|
331 }
|
|
|
332 if (!isdummy(nold))
|
|
|
333 luaM_freearray(L, nold, cast(size_t, twoto(oldhsize))); /* free old array */
|
|
|
334 }
|
|
|
335
|
|
|
336
|
|
|
337 void luaH_resizearray (lua_State *L, Table *t, int nasize) {
|
|
|
338 int nsize = isdummy(t->node) ? 0 : sizenode(t);
|
|
|
339 luaH_resize(L, t, nasize, nsize);
|
|
|
340 }
|
|
|
341
|
|
|
342
|
|
|
343 static void rehash (lua_State *L, Table *t, const TValue *ek) {
|
|
|
344 int nasize, na;
|
|
|
345 int nums[MAXBITS+1]; /* nums[i] = number of keys with 2^(i-1) < k <= 2^i */
|
|
|
346 int i;
|
|
|
347 int totaluse;
|
|
|
348 for (i=0; i<=MAXBITS; i++) nums[i] = 0; /* reset counts */
|
|
|
349 nasize = numusearray(t, nums); /* count keys in array part */
|
|
|
350 totaluse = nasize; /* all those keys are integer keys */
|
|
|
351 totaluse += numusehash(t, nums, &nasize); /* count keys in hash part */
|
|
|
352 /* count extra key */
|
|
|
353 nasize += countint(ek, nums);
|
|
|
354 totaluse++;
|
|
|
355 /* compute new size for array part */
|
|
|
356 na = computesizes(nums, &nasize);
|
|
|
357 /* resize the table to new computed sizes */
|
|
|
358 luaH_resize(L, t, nasize, totaluse - na);
|
|
|
359 }
|
|
|
360
|
|
|
361
|
|
|
362
|
|
|
363 /*
|
|
|
364 ** }=============================================================
|
|
|
365 */
|
|
|
366
|
|
|
367
|
|
|
368 Table *luaH_new (lua_State *L) {
|
|
|
369 Table *t = &luaC_newobj(L, LUA_TTABLE, sizeof(Table), NULL, 0)->h;
|
|
|
370 t->metatable = NULL;
|
|
|
371 t->flags = cast_byte(~0);
|
|
|
372 t->array = NULL;
|
|
|
373 t->sizearray = 0;
|
|
|
374 setnodevector(L, t, 0);
|
|
|
375 return t;
|
|
|
376 }
|
|
|
377
|
|
|
378
|
|
|
379 void luaH_free (lua_State *L, Table *t) {
|
|
|
380 if (!isdummy(t->node))
|
|
|
381 luaM_freearray(L, t->node, cast(size_t, sizenode(t)));
|
|
|
382 luaM_freearray(L, t->array, t->sizearray);
|
|
|
383 luaM_free(L, t);
|
|
|
384 }
|
|
|
385
|
|
|
386
|
|
|
387 static Node *getfreepos (Table *t) {
|
|
|
388 while (t->lastfree > t->node) {
|
|
|
389 t->lastfree--;
|
|
|
390 if (ttisnil(gkey(t->lastfree)))
|
|
|
391 return t->lastfree;
|
|
|
392 }
|
|
|
393 return NULL; /* could not find a free place */
|
|
|
394 }
|
|
|
395
|
|
|
396
|
|
|
397
|
|
|
398 /*
|
|
|
399 ** inserts a new key into a hash table; first, check whether key's main
|
|
|
400 ** position is free. If not, check whether colliding node is in its main
|
|
|
401 ** position or not: if it is not, move colliding node to an empty place and
|
|
|
402 ** put new key in its main position; otherwise (colliding node is in its main
|
|
|
403 ** position), new key goes to an empty position.
|
|
|
404 */
|
|
|
405 TValue *luaH_newkey (lua_State *L, Table *t, const TValue *key) {
|
|
|
406 Node *mp;
|
|
|
407 if (ttisnil(key)) luaG_runerror(L, "table index is nil");
|
|
|
408 else if (ttisnumber(key) && luai_numisnan(L, nvalue(key)))
|
|
|
409 luaG_runerror(L, "table index is NaN");
|
|
|
410 mp = mainposition(t, key);
|
|
|
411 if (!ttisnil(gval(mp)) || isdummy(mp)) { /* main position is taken? */
|
|
|
412 Node *othern;
|
|
|
413 Node *n = getfreepos(t); /* get a free place */
|
|
|
414 if (n == NULL) { /* cannot find a free place? */
|
|
|
415 rehash(L, t, key); /* grow table */
|
|
|
416 /* whatever called 'newkey' take care of TM cache and GC barrier */
|
|
|
417 return luaH_set(L, t, key); /* insert key into grown table */
|
|
|
418 }
|
|
|
419 lua_assert(!isdummy(n));
|
|
|
420 othern = mainposition(t, gkey(mp));
|
|
|
421 if (othern != mp) { /* is colliding node out of its main position? */
|
|
|
422 /* yes; move colliding node into free position */
|
|
|
423 while (gnext(othern) != mp) othern = gnext(othern); /* find previous */
|
|
|
424 gnext(othern) = n; /* redo the chain with `n' in place of `mp' */
|
|
|
425 *n = *mp; /* copy colliding node into free pos. (mp->next also goes) */
|
|
|
426 gnext(mp) = NULL; /* now `mp' is free */
|
|
|
427 setnilvalue(gval(mp));
|
|
|
428 }
|
|
|
429 else { /* colliding node is in its own main position */
|
|
|
430 /* new node will go into free position */
|
|
|
431 gnext(n) = gnext(mp); /* chain new position */
|
|
|
432 gnext(mp) = n;
|
|
|
433 mp = n;
|
|
|
434 }
|
|
|
435 }
|
|
|
436 setobj2t(L, gkey(mp), key);
|
|
|
437 luaC_barrierback(L, obj2gco(t), key);
|
|
|
438 lua_assert(ttisnil(gval(mp)));
|
|
|
439 return gval(mp);
|
|
|
440 }
|
|
|
441
|
|
|
442
|
|
|
443 /*
|
|
|
444 ** search function for integers
|
|
|
445 */
|
|
|
446 const TValue *luaH_getint (Table *t, int key) {
|
|
|
447 /* (1 <= key && key <= t->sizearray) */
|
|
|
448 if (cast(unsigned int, key-1) < cast(unsigned int, t->sizearray))
|
|
|
449 return &t->array[key-1];
|
|
|
450 else {
|
|
|
451 lua_Number nk = cast_num(key);
|
|
|
452 Node *n = hashnum(t, nk);
|
|
|
453 do { /* check whether `key' is somewhere in the chain */
|
|
|
454 if (ttisnumber(gkey(n)) && luai_numeq(nvalue(gkey(n)), nk))
|
|
|
455 return gval(n); /* that's it */
|
|
|
456 else n = gnext(n);
|
|
|
457 } while (n);
|
|
|
458 return luaO_nilobject;
|
|
|
459 }
|
|
|
460 }
|
|
|
461
|
|
|
462
|
|
|
463 /*
|
|
|
464 ** search function for short strings
|
|
|
465 */
|
|
|
466 const TValue *luaH_getstr (Table *t, TString *key) {
|
|
|
467 Node *n = hashstr(t, key);
|
|
|
468 lua_assert(key->tsv.tt == LUA_TSHRSTR);
|
|
|
469 do { /* check whether `key' is somewhere in the chain */
|
|
|
470 if (ttisshrstring(gkey(n)) && eqshrstr(rawtsvalue(gkey(n)), key))
|
|
|
471 return gval(n); /* that's it */
|
|
|
472 else n = gnext(n);
|
|
|
473 } while (n);
|
|
|
474 return luaO_nilobject;
|
|
|
475 }
|
|
|
476
|
|
|
477
|
|
|
478 /*
|
|
|
479 ** main search function
|
|
|
480 */
|
|
|
481 const TValue *luaH_get (Table *t, const TValue *key) {
|
|
|
482 switch (ttype(key)) {
|
|
|
483 case LUA_TSHRSTR: return luaH_getstr(t, rawtsvalue(key));
|
|
|
484 case LUA_TNIL: return luaO_nilobject;
|
|
|
485 case LUA_TNUMBER: {
|
|
|
486 int k;
|
|
|
487 lua_Number n = nvalue(key);
|
|
|
488 lua_number2int(k, n);
|
|
|
489 if (luai_numeq(cast_num(k), n)) /* index is int? */
|
|
|
490 return luaH_getint(t, k); /* use specialized version */
|
|
|
491 /* else go through */
|
|
|
492 }
|
|
|
493 default: {
|
|
|
494 Node *n = mainposition(t, key);
|
|
|
495 do { /* check whether `key' is somewhere in the chain */
|
|
|
496 if (luaV_rawequalobj(gkey(n), key))
|
|
|
497 return gval(n); /* that's it */
|
|
|
498 else n = gnext(n);
|
|
|
499 } while (n);
|
|
|
500 return luaO_nilobject;
|
|
|
501 }
|
|
|
502 }
|
|
|
503 }
|
|
|
504
|
|
|
505
|
|
|
506 /*
|
|
|
507 ** beware: when using this function you probably need to check a GC
|
|
|
508 ** barrier and invalidate the TM cache.
|
|
|
509 */
|
|
|
510 TValue *luaH_set (lua_State *L, Table *t, const TValue *key) {
|
|
|
511 const TValue *p = luaH_get(t, key);
|
|
|
512 if (p != luaO_nilobject)
|
|
|
513 return cast(TValue *, p);
|
|
|
514 else return luaH_newkey(L, t, key);
|
|
|
515 }
|
|
|
516
|
|
|
517
|
|
|
518 void luaH_setint (lua_State *L, Table *t, int key, TValue *value) {
|
|
|
519 const TValue *p = luaH_getint(t, key);
|
|
|
520 TValue *cell;
|
|
|
521 if (p != luaO_nilobject)
|
|
|
522 cell = cast(TValue *, p);
|
|
|
523 else {
|
|
|
524 TValue k;
|
|
|
525 setnvalue(&k, cast_num(key));
|
|
|
526 cell = luaH_newkey(L, t, &k);
|
|
|
527 }
|
|
|
528 setobj2t(L, cell, value);
|
|
|
529 }
|
|
|
530
|
|
|
531
|
|
|
532 static int unbound_search (Table *t, unsigned int j) {
|
|
|
533 unsigned int i = j; /* i is zero or a present index */
|
|
|
534 j++;
|
|
|
535 /* find `i' and `j' such that i is present and j is not */
|
|
|
536 while (!ttisnil(luaH_getint(t, j))) {
|
|
|
537 i = j;
|
|
|
538 j *= 2;
|
|
|
539 if (j > cast(unsigned int, MAX_INT)) { /* overflow? */
|
|
|
540 /* table was built with bad purposes: resort to linear search */
|
|
|
541 i = 1;
|
|
|
542 while (!ttisnil(luaH_getint(t, i))) i++;
|
|
|
543 return i - 1;
|
|
|
544 }
|
|
|
545 }
|
|
|
546 /* now do a binary search between them */
|
|
|
547 while (j - i > 1) {
|
|
|
548 unsigned int m = (i+j)/2;
|
|
|
549 if (ttisnil(luaH_getint(t, m))) j = m;
|
|
|
550 else i = m;
|
|
|
551 }
|
|
|
552 return i;
|
|
|
553 }
|
|
|
554
|
|
|
555
|
|
|
556 /*
|
|
|
557 ** Try to find a boundary in table `t'. A `boundary' is an integer index
|
|
|
558 ** such that t[i] is non-nil and t[i+1] is nil (and 0 if t[1] is nil).
|
|
|
559 */
|
|
|
560 int luaH_getn (Table *t) {
|
|
|
561 unsigned int j = t->sizearray;
|
|
|
562 if (j > 0 && ttisnil(&t->array[j - 1])) {
|
|
|
563 /* there is a boundary in the array part: (binary) search for it */
|
|
|
564 unsigned int i = 0;
|
|
|
565 while (j - i > 1) {
|
|
|
566 unsigned int m = (i+j)/2;
|
|
|
567 if (ttisnil(&t->array[m - 1])) j = m;
|
|
|
568 else i = m;
|
|
|
569 }
|
|
|
570 return i;
|
|
|
571 }
|
|
|
572 /* else must find a boundary in hash part */
|
|
|
573 else if (isdummy(t->node)) /* hash part is empty? */
|
|
|
574 return j; /* that is easy... */
|
|
|
575 else return unbound_search(t, j);
|
|
|
576 }
|
|
|
577
|
|
|
578
|
|
|
579
|
|
|
580 #if defined(LUA_DEBUG)
|
|
|
581
|
|
|
582 Node *luaH_mainposition (const Table *t, const TValue *key) {
|
|
|
583 return mainposition(t, key);
|
|
|
584 }
|
|
|
585
|
|
|
586 int luaH_isdummy (Node *n) { return isdummy(n); }
|
|
|
587
|
|
|
588 #endif
|
