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1 : : /*
2 : : ** $Id: ltable.c $
3 : : ** Lua tables (hash)
4 : : ** See Copyright Notice in lua.h
5 : : */
6 : :
7 : : #define ltable_c
8 : : #define LUA_CORE
9 : :
10 : : #include "lprefix.h"
11 : :
12 : :
13 : : /*
14 : : ** Implementation of tables (aka arrays, objects, or hash tables).
15 : : ** Tables keep its elements in two parts: an array part and a hash part.
16 : : ** Non-negative integer keys are all candidates to be kept in the array
17 : : ** part. The actual size of the array is the largest 'n' such that
18 : : ** more than half the slots between 1 and n are in use.
19 : : ** Hash uses a mix of chained scatter table with Brent's variation.
20 : : ** A main invariant of these tables is that, if an element is not
21 : : ** in its main position (i.e. the 'original' position that its hash gives
22 : : ** to it), then the colliding element is in its own main position.
23 : : ** Hence even when the load factor reaches 100%, performance remains good.
24 : : */
25 : :
26 : : #include <math.h>
27 : : #include <limits.h>
28 : :
29 : : #include "lua.h"
30 : :
31 : : #include "ldebug.h"
32 : : #include "ldo.h"
33 : : #include "lgc.h"
34 : : #include "lmem.h"
35 : : #include "lobject.h"
36 : : #include "lstate.h"
37 : : #include "lstring.h"
38 : : #include "ltable.h"
39 : : #include "lvm.h"
40 : :
41 : :
42 : : /*
43 : : ** MAXABITS is the largest integer such that MAXASIZE fits in an
44 : : ** unsigned int.
45 : : */
46 : : #define MAXABITS cast_int(sizeof(int) * CHAR_BIT - 1)
47 : :
48 : :
49 : : /*
50 : : ** MAXASIZE is the maximum size of the array part. It is the minimum
51 : : ** between 2^MAXABITS and the maximum size that, measured in bytes,
52 : : ** fits in a 'size_t'.
53 : : */
54 : : #define MAXASIZE luaM_limitN(1u << MAXABITS, TValue)
55 : :
56 : : /*
57 : : ** MAXHBITS is the largest integer such that 2^MAXHBITS fits in a
58 : : ** signed int.
59 : : */
60 : : #define MAXHBITS (MAXABITS - 1)
61 : :
62 : :
63 : : /*
64 : : ** MAXHSIZE is the maximum size of the hash part. It is the minimum
65 : : ** between 2^MAXHBITS and the maximum size such that, measured in bytes,
66 : : ** it fits in a 'size_t'.
67 : : */
68 : : #define MAXHSIZE luaM_limitN(1u << MAXHBITS, Node)
69 : :
70 : :
71 : : #define hashpow2(t,n) (gnode(t, lmod((n), sizenode(t))))
72 : :
73 : : #define hashstr(t,str) hashpow2(t, (str)->hash)
74 : : #define hashboolean(t,p) hashpow2(t, p)
75 : : #define hashint(t,i) hashpow2(t, i)
76 : :
77 : :
78 : : /*
79 : : ** for some types, it is better to avoid modulus by power of 2, as
80 : : ** they tend to have many 2 factors.
81 : : */
82 : : #define hashmod(t,n) (gnode(t, ((n) % ((sizenode(t)-1)|1))))
83 : :
84 : :
85 : : #define hashpointer(t,p) hashmod(t, point2uint(p))
86 : :
87 : :
88 : : #define dummynode (&dummynode_)
89 : :
90 : : static const Node dummynode_ = {
91 : : {{NULL}, LUA_VEMPTY, /* value's value and type */
92 : : LUA_VNIL, 0, {NULL}} /* key type, next, and key value */
93 : : };
94 : :
95 : :
96 : : static const TValue absentkey = {ABSTKEYCONSTANT};
97 : :
98 : :
99 : :
100 : : /*
101 : : ** Hash for floating-point numbers.
102 : : ** The main computation should be just
103 : : ** n = frexp(n, &i); return (n * INT_MAX) + i
104 : : ** but there are some numerical subtleties.
105 : : ** In a two-complement representation, INT_MAX does not has an exact
106 : : ** representation as a float, but INT_MIN does; because the absolute
107 : : ** value of 'frexp' is smaller than 1 (unless 'n' is inf/NaN), the
108 : : ** absolute value of the product 'frexp * -INT_MIN' is smaller or equal
109 : : ** to INT_MAX. Next, the use of 'unsigned int' avoids overflows when
110 : : ** adding 'i'; the use of '~u' (instead of '-u') avoids problems with
111 : : ** INT_MIN.
112 : : */
113 : : #if !defined(l_hashfloat)
114 : 0 : static int l_hashfloat (lua_Number n) {
115 : : int i;
116 : : lua_Integer ni;
117 : 0 : n = l_mathop(frexp)(n, &i) * -cast_num(INT_MIN);
118 [ # # # # : 0 : if (!lua_numbertointeger(n, &ni)) { /* is 'n' inf/-inf/NaN? */
# # ]
119 : : lua_assert(luai_numisnan(n) || l_mathop(fabs)(n) == cast_num(HUGE_VAL));
120 : 0 : return 0;
121 : : }
122 : : else { /* normal case */
123 : 0 : unsigned int u = cast_uint(i) + cast_uint(ni);
124 [ # # ]: 0 : return cast_int(u <= cast_uint(INT_MAX) ? u : ~u);
125 : : }
126 : 0 : }
127 : : #endif
128 : :
129 : :
130 : : /*
131 : : ** returns the 'main' position of an element in a table (that is,
132 : : ** the index of its hash value). The key comes broken (tag in 'ktt'
133 : : ** and value in 'vkl') so that we can call it on keys inserted into
134 : : ** nodes.
135 : : */
136 : 337743 : static Node *mainposition (const Table *t, int ktt, const Value *kvl) {
137 [ + - + + : 337743 : switch (withvariant(ktt)) {
+ + - +
+ ]
138 : : case LUA_VNUMINT:
139 : 150 : return hashint(t, ivalueraw(*kvl));
140 : : case LUA_VNUMFLT:
141 : 0 : return hashmod(t, l_hashfloat(fltvalueraw(*kvl)));
142 : : case LUA_VSHRSTR:
143 : 336763 : return hashstr(t, tsvalueraw(*kvl));
144 : : case LUA_VLNGSTR:
145 : 88 : return hashpow2(t, luaS_hashlongstr(tsvalueraw(*kvl)));
146 : : case LUA_VFALSE:
147 : 32 : return hashboolean(t, 0);
148 : : case LUA_VTRUE:
149 : 82 : return hashboolean(t, 1);
150 : : case LUA_VLIGHTUSERDATA:
151 : 0 : return hashpointer(t, pvalueraw(*kvl));
152 : : case LUA_VLCF:
153 : 1 : return hashpointer(t, fvalueraw(*kvl));
154 : : default:
155 : 627 : return hashpointer(t, gcvalueraw(*kvl));
156 : : }
157 : 337743 : }
158 : :
159 : :
160 : : /*
161 : : ** Returns the main position of an element given as a 'TValue'
162 : : */
163 : 254021 : static Node *mainpositionTV (const Table *t, const TValue *key) {
164 : 254021 : return mainposition(t, rawtt(key), valraw(key));
165 : : }
166 : :
167 : :
168 : : /*
169 : : ** Check whether key 'k1' is equal to the key in node 'n2'. This
170 : : ** equality is raw, so there are no metamethods. Floats with integer
171 : : ** values have been normalized, so integers cannot be equal to
172 : : ** floats. It is assumed that 'eqshrstr' is simply pointer equality, so
173 : : ** that short strings are handled in the default case.
174 : : ** A true 'deadok' means to accept dead keys as equal to their original
175 : : ** values. All dead keys are compared in the default case, by pointer
176 : : ** identity. (Only collectable objects can produce dead keys.) Note that
177 : : ** dead long strings are also compared by identity.
178 : : ** Once a key is dead, its corresponding value may be collected, and
179 : : ** then another value can be created with the same address. If this
180 : : ** other value is given to 'next', 'equalkey' will signal a false
181 : : ** positive. In a regular traversal, this situation should never happen,
182 : : ** as all keys given to 'next' came from the table itself, and therefore
183 : : ** could not have been collected. Outside a regular traversal, we
184 : : ** have garbage in, garbage out. What is relevant is that this false
185 : : ** positive does not break anything. (In particular, 'next' will return
186 : : ** some other valid item on the table or nil.)
187 : : */
188 : 442 : static int equalkey (const TValue *k1, const Node *n2, int deadok) {
189 [ + + # # ]: 442 : if ((rawtt(k1) != keytt(n2)) && /* not the same variants? */
190 [ - + # # ]: 426 : !(deadok && keyisdead(n2) && iscollectable(k1)))
191 : 426 : return 0; /* cannot be same key */
192 [ - - - - : 16 : switch (keytt(n2)) {
+ - - ]
193 : : case LUA_VNIL: case LUA_VFALSE: case LUA_VTRUE:
194 : 0 : return 1;
195 : : case LUA_VNUMINT:
196 : 0 : return (ivalue(k1) == keyival(n2));
197 : : case LUA_VNUMFLT:
198 : 0 : return luai_numeq(fltvalue(k1), fltvalueraw(keyval(n2)));
199 : : case LUA_VLIGHTUSERDATA:
200 : 0 : return pvalue(k1) == pvalueraw(keyval(n2));
201 : : case LUA_VLCF:
202 : 0 : return fvalue(k1) == fvalueraw(keyval(n2));
203 : : case ctb(LUA_VLNGSTR):
204 : 16 : return luaS_eqlngstr(tsvalue(k1), keystrval(n2));
205 : : default:
206 : 0 : return gcvalue(k1) == gcvalueraw(keyval(n2));
207 : : }
208 : 442 : }
209 : :
210 : :
211 : : /*
212 : : ** True if value of 'alimit' is equal to the real size of the array
213 : : ** part of table 't'. (Otherwise, the array part must be larger than
214 : : ** 'alimit'.)
215 : : */
216 : : #define limitequalsasize(t) (isrealasize(t) || ispow2((t)->alimit))
217 : :
218 : :
219 : : /*
220 : : ** Returns the real size of the 'array' array
221 : : */
222 : 67483 : LUAI_FUNC unsigned int luaH_realasize (const Table *t) {
223 [ - + # # ]: 67483 : if (limitequalsasize(t))
224 : 67483 : return t->alimit; /* this is the size */
225 : : else {
226 : 0 : unsigned int size = t->alimit;
227 : : /* compute the smallest power of 2 not smaller than 'n' */
228 : 0 : size |= (size >> 1);
229 : 0 : size |= (size >> 2);
230 : 0 : size |= (size >> 4);
231 : 0 : size |= (size >> 8);
232 : 0 : size |= (size >> 16);
233 : : #if (UINT_MAX >> 30) > 3
234 : : size |= (size >> 32); /* unsigned int has more than 32 bits */
235 : : #endif
236 : 0 : size++;
237 : : lua_assert(ispow2(size) && size/2 < t->alimit && t->alimit < size);
238 : 0 : return size;
239 : : }
240 : 67483 : }
241 : :
242 : :
243 : : /*
244 : : ** Check whether real size of the array is a power of 2.
245 : : ** (If it is not, 'alimit' cannot be changed to any other value
246 : : ** without changing the real size.)
247 : : */
248 : 25 : static int ispow2realasize (const Table *t) {
249 [ - + ]: 25 : return (!isrealasize(t) || ispow2(t->alimit));
250 : : }
251 : :
252 : :
253 : 47112 : static unsigned int setlimittosize (Table *t) {
254 : 47112 : t->alimit = luaH_realasize(t);
255 : 47112 : setrealasize(t);
256 : 47112 : return t->alimit;
257 : : }
258 : :
259 : :
260 : : #define limitasasize(t) check_exp(isrealasize(t), t->alimit)
261 : :
262 : :
263 : :
264 : : /*
265 : : ** "Generic" get version. (Not that generic: not valid for integers,
266 : : ** which may be in array part, nor for floats with integral values.)
267 : : ** See explanation about 'deadok' in function 'equalkey'.
268 : : */
269 : 375 : static const TValue *getgeneric (Table *t, const TValue *key, int deadok) {
270 : 375 : Node *n = mainpositionTV(t, key);
271 : 442 : for (;;) { /* check whether 'key' is somewhere in the chain */
272 [ + + ]: 442 : if (equalkey(key, n, deadok))
273 : 16 : return gval(n); /* that's it */
274 : : else {
275 : 426 : int nx = gnext(n);
276 [ + + ]: 426 : if (nx == 0)
277 : 359 : return &absentkey; /* not found */
278 : 67 : n += nx;
279 : : }
280 : : }
281 : 375 : }
282 : :
283 : :
284 : : /*
285 : : ** returns the index for 'k' if 'k' is an appropriate key to live in
286 : : ** the array part of a table, 0 otherwise.
287 : : */
288 : 150 : static unsigned int arrayindex (lua_Integer k) {
289 [ + - ]: 150 : if (l_castS2U(k) - 1u < MAXASIZE) /* 'k' in [1, MAXASIZE]? */
290 : 150 : return cast_uint(k); /* 'key' is an appropriate array index */
291 : : else
292 : 0 : return 0;
293 : 150 : }
294 : :
295 : :
296 : : /*
297 : : ** returns the index of a 'key' for table traversals. First goes all
298 : : ** elements in the array part, then elements in the hash part. The
299 : : ** beginning of a traversal is signaled by 0.
300 : : */
301 : 0 : static unsigned int findindex (lua_State *L, Table *t, TValue *key,
302 : : unsigned int asize) {
303 : : unsigned int i;
304 [ # # ]: 0 : if (ttisnil(key)) return 0; /* first iteration */
305 [ # # ]: 0 : i = ttisinteger(key) ? arrayindex(ivalue(key)) : 0;
306 [ # # ]: 0 : if (i - 1u < asize) /* is 'key' inside array part? */
307 : 0 : return i; /* yes; that's the index */
308 : : else {
309 : 0 : const TValue *n = getgeneric(t, key, 1);
310 [ # # ]: 0 : if (unlikely(isabstkey(n)))
311 : 0 : luaG_runerror(L, "invalid key to 'next'"); /* key not found */
312 : 0 : i = cast_int(nodefromval(n) - gnode(t, 0)); /* key index in hash table */
313 : : /* hash elements are numbered after array ones */
314 : 0 : return (i + 1) + asize;
315 : : }
316 : 0 : }
317 : :
318 : :
319 : 0 : int luaH_next (lua_State *L, Table *t, StkId key) {
320 : 0 : unsigned int asize = luaH_realasize(t);
321 : 0 : unsigned int i = findindex(L, t, s2v(key), asize); /* find original key */
322 [ # # ]: 0 : for (; i < asize; i++) { /* try first array part */
323 [ # # ]: 0 : if (!isempty(&t->array[i])) { /* a non-empty entry? */
324 : 0 : setivalue(s2v(key), i + 1);
325 : 0 : setobj2s(L, key + 1, &t->array[i]);
326 : 0 : return 1;
327 : : }
328 : 0 : }
329 [ # # ]: 0 : for (i -= asize; cast_int(i) < sizenode(t); i++) { /* hash part */
330 [ # # ]: 0 : if (!isempty(gval(gnode(t, i)))) { /* a non-empty entry? */
331 : 0 : Node *n = gnode(t, i);
332 : 0 : getnodekey(L, s2v(key), n);
333 : 0 : setobj2s(L, key + 1, gval(n));
334 : 0 : return 1;
335 : : }
336 : 0 : }
337 : 0 : return 0; /* no more elements */
338 : 0 : }
339 : :
340 : :
341 : 31066 : static void freehash (lua_State *L, Table *t) {
342 [ + + ]: 31066 : if (!isdummy(t))
343 : 14749 : luaM_freearray(L, t->node, cast_sizet(sizenode(t)));
344 : 31066 : }
345 : :
346 : :
347 : : /*
348 : : ** {=============================================================
349 : : ** Rehash
350 : : ** ==============================================================
351 : : */
352 : :
353 : : /*
354 : : ** Compute the optimal size for the array part of table 't'. 'nums' is a
355 : : ** "count array" where 'nums[i]' is the number of integers in the table
356 : : ** between 2^(i - 1) + 1 and 2^i. 'pna' enters with the total number of
357 : : ** integer keys in the table and leaves with the number of keys that
358 : : ** will go to the array part; return the optimal size. (The condition
359 : : ** 'twotoi > 0' in the for loop stops the loop if 'twotoi' overflows.)
360 : : */
361 : 17091 : static unsigned int computesizes (unsigned int nums[], unsigned int *pna) {
362 : : int i;
363 : : unsigned int twotoi; /* 2^i (candidate for optimal size) */
364 : 17091 : unsigned int a = 0; /* number of elements smaller than 2^i */
365 : 17091 : unsigned int na = 0; /* number of elements to go to array part */
366 : 17091 : unsigned int optimal = 0; /* optimal size for array part */
367 : : /* loop while keys can fill more than half of total size */
368 [ + + ]: 47670 : for (i = 0, twotoi = 1;
369 [ - + ]: 23835 : twotoi > 0 && *pna > twotoi / 2;
370 : 6744 : i++, twotoi *= 2) {
371 : 6744 : a += nums[i];
372 [ - + ]: 6744 : if (a > twotoi/2) { /* more than half elements present? */
373 : 6744 : optimal = twotoi; /* optimal size (till now) */
374 : 6744 : na = a; /* all elements up to 'optimal' will go to array part */
375 : 6744 : }
376 : 6744 : }
377 : : lua_assert((optimal == 0 || optimal / 2 < na) && na <= optimal);
378 : 17091 : *pna = na;
379 : 17091 : return optimal;
380 : : }
381 : :
382 : :
383 : 150 : static int countint (lua_Integer key, unsigned int *nums) {
384 : 150 : unsigned int k = arrayindex(key);
385 [ + - ]: 150 : if (k != 0) { /* is 'key' an appropriate array index? */
386 : 150 : nums[luaO_ceillog2(k)]++; /* count as such */
387 : 150 : return 1;
388 : : }
389 : : else
390 : 0 : return 0;
391 : 150 : }
392 : :
393 : :
394 : : /*
395 : : ** Count keys in array part of table 't': Fill 'nums[i]' with
396 : : ** number of keys that will go into corresponding slice and return
397 : : ** total number of non-nil keys.
398 : : */
399 : 17091 : static unsigned int numusearray (const Table *t, unsigned int *nums) {
400 : : int lg;
401 : : unsigned int ttlg; /* 2^lg */
402 : 17091 : unsigned int ause = 0; /* summation of 'nums' */
403 : 17091 : unsigned int i = 1; /* count to traverse all array keys */
404 : 17091 : unsigned int asize = limitasasize(t); /* real array size */
405 : : /* traverse each slice */
406 [ - + ]: 23685 : for (lg = 0, ttlg = 1; lg <= MAXABITS; lg++, ttlg *= 2) {
407 : 23685 : unsigned int lc = 0; /* counter */
408 : 23685 : unsigned int lim = ttlg;
409 [ + + ]: 23685 : if (lim > asize) {
410 : 17091 : lim = asize; /* adjust upper limit */
411 [ + - ]: 17091 : if (i > lim)
412 : 17091 : break; /* no more elements to count */
413 : 0 : }
414 : : /* count elements in range (2^(lg - 1), 2^lg] */
415 [ + + ]: 13188 : for (; i <= lim; i++) {
416 [ - + ]: 6594 : if (!isempty(&t->array[i-1]))
417 : 6594 : lc++;
418 : 6594 : }
419 : 6594 : nums[lg] += lc;
420 : 6594 : ause += lc;
421 : 6594 : }
422 : 17091 : return ause;
423 : : }
424 : :
425 : :
426 : 17091 : static int numusehash (const Table *t, unsigned int *nums, unsigned int *pna) {
427 : 17091 : int totaluse = 0; /* total number of elements */
428 : 17091 : int ause = 0; /* elements added to 'nums' (can go to array part) */
429 : 17091 : int i = sizenode(t);
430 [ + + ]: 98413 : while (i--) {
431 : 81322 : Node *n = &t->node[i];
432 [ + + ]: 81322 : if (!isempty(gval(n))) {
433 [ + - ]: 78055 : if (keyisinteger(n))
434 : 0 : ause += countint(keyival(n), nums);
435 : 78055 : totaluse++;
436 : 78055 : }
437 : : }
438 : 17091 : *pna += ause;
439 : 17091 : return totaluse;
440 : : }
441 : :
442 : :
443 : : /*
444 : : ** Creates an array for the hash part of a table with the given
445 : : ** size, or reuses the dummy node if size is zero.
446 : : ** The computation for size overflow is in two steps: the first
447 : : ** comparison ensures that the shift in the second one does not
448 : : ** overflow.
449 : : */
450 : 46940 : static void setnodevector (lua_State *L, Table *t, unsigned int size) {
451 [ + + ]: 46940 : if (size == 0) { /* no elements to hash part? */
452 : 18698 : t->node = cast(Node *, dummynode); /* use common 'dummynode' */
453 : 18698 : t->lsizenode = 0;
454 : 18698 : t->lastfree = NULL; /* signal that it is using dummy node */
455 : 18698 : }
456 : : else {
457 : : int i;
458 : 28242 : int lsize = luaO_ceillog2(size);
459 [ + - ]: 28242 : if (lsize > MAXHBITS || (1u << lsize) > MAXHSIZE)
460 : 0 : luaG_runerror(L, "table overflow");
461 : 28242 : size = twoto(lsize);
462 : 28242 : t->node = luaM_newvector(L, size, Node);
463 [ + + ]: 340029 : for (i = 0; i < (int)size; i++) {
464 : 311787 : Node *n = gnode(t, i);
465 : 311787 : gnext(n) = 0;
466 : 311787 : setnilkey(n);
467 : 311787 : setempty(gval(n));
468 : 311787 : }
469 : 28242 : t->lsizenode = cast_byte(lsize);
470 : 28242 : t->lastfree = gnode(t, size); /* all positions are free */
471 : : }
472 : 46940 : }
473 : :
474 : :
475 : : /*
476 : : ** (Re)insert all elements from the hash part of 'ot' into table 't'.
477 : : */
478 : 30021 : static void reinsert (lua_State *L, Table *ot, Table *t) {
479 : : int j;
480 : 30021 : int size = sizenode(ot);
481 [ + + ]: 124273 : for (j = 0; j < size; j++) {
482 : 94252 : Node *old = gnode(ot, j);
483 [ + + ]: 94252 : if (!isempty(gval(old))) {
484 : : /* doesn't need barrier/invalidate cache, as entry was
485 : : already present in the table */
486 : : TValue k;
487 : 78055 : getnodekey(L, &k, old);
488 : 78055 : setobjt2t(L, luaH_set(L, t, &k), gval(old));
489 : 78055 : }
490 : 94252 : }
491 : 30021 : }
492 : :
493 : :
494 : : /*
495 : : ** Exchange the hash part of 't1' and 't2'.
496 : : */
497 : 30021 : static void exchangehashpart (Table *t1, Table *t2) {
498 : 30021 : lu_byte lsizenode = t1->lsizenode;
499 : 30021 : Node *node = t1->node;
500 : 30021 : Node *lastfree = t1->lastfree;
501 : 30021 : t1->lsizenode = t2->lsizenode;
502 : 30021 : t1->node = t2->node;
503 : 30021 : t1->lastfree = t2->lastfree;
504 : 30021 : t2->lsizenode = lsizenode;
505 : 30021 : t2->node = node;
506 : 30021 : t2->lastfree = lastfree;
507 : 30021 : }
508 : :
509 : :
510 : : /*
511 : : ** Resize table 't' for the new given sizes. Both allocations (for
512 : : ** the hash part and for the array part) can fail, which creates some
513 : : ** subtleties. If the first allocation, for the hash part, fails, an
514 : : ** error is raised and that is it. Otherwise, it copies the elements from
515 : : ** the shrinking part of the array (if it is shrinking) into the new
516 : : ** hash. Then it reallocates the array part. If that fails, the table
517 : : ** is in its original state; the function frees the new hash part and then
518 : : ** raises the allocation error. Otherwise, it sets the new hash part
519 : : ** into the table, initializes the new part of the array (if any) with
520 : : ** nils and reinserts the elements of the old hash back into the new
521 : : ** parts of the table.
522 : : */
523 : 30021 : void luaH_resize (lua_State *L, Table *t, unsigned int newasize,
524 : : unsigned int nhsize) {
525 : : unsigned int i;
526 : : Table newt; /* to keep the new hash part */
527 : 30021 : unsigned int oldasize = setlimittosize(t);
528 : : TValue *newarray;
529 : : /* create new hash part with appropriate size into 'newt' */
530 : 30021 : setnodevector(L, &newt, nhsize);
531 [ + - ]: 30021 : if (newasize < oldasize) { /* will array shrink? */
532 : 0 : t->alimit = newasize; /* pretend array has new size... */
533 : 0 : exchangehashpart(t, &newt); /* and new hash */
534 : : /* re-insert into the new hash the elements from vanishing slice */
535 [ # # ]: 0 : for (i = newasize; i < oldasize; i++) {
536 [ # # ]: 0 : if (!isempty(&t->array[i]))
537 : 0 : luaH_setint(L, t, i + 1, &t->array[i]);
538 : 0 : }
539 : 0 : t->alimit = oldasize; /* restore current size... */
540 : 0 : exchangehashpart(t, &newt); /* and hash (in case of errors) */
541 : 0 : }
542 : : /* allocate new array */
543 : 30021 : newarray = luaM_reallocvector(L, t->array, oldasize, newasize, TValue);
544 [ + + - + ]: 30021 : if (unlikely(newarray == NULL && newasize > 0)) { /* allocation failed? */
545 : 0 : freehash(L, &newt); /* release new hash part */
546 : 0 : luaM_error(L); /* raise error (with array unchanged) */
547 : : }
548 : : /* allocation ok; initialize new part of the array */
549 : 30021 : exchangehashpart(t, &newt); /* 't' has the new hash ('newt' has the old) */
550 : 30021 : t->array = newarray; /* set new array part */
551 : 30021 : t->alimit = newasize;
552 [ + + ]: 35141 : for (i = oldasize; i < newasize; i++) /* clear new slice of the array */
553 : 5120 : setempty(&t->array[i]);
554 : : /* re-insert elements from old hash part into new parts */
555 : 30021 : reinsert(L, &newt, t); /* 'newt' now has the old hash */
556 : 30021 : freehash(L, &newt); /* free old hash part */
557 : 30021 : }
558 : :
559 : :
560 : 0 : void luaH_resizearray (lua_State *L, Table *t, unsigned int nasize) {
561 [ # # ]: 0 : int nsize = allocsizenode(t);
562 : 0 : luaH_resize(L, t, nasize, nsize);
563 : 0 : }
564 : :
565 : : /*
566 : : ** nums[i] = number of keys 'k' where 2^(i - 1) < k <= 2^i
567 : : */
568 : 17091 : static void rehash (lua_State *L, Table *t, const TValue *ek) {
569 : : unsigned int asize; /* optimal size for array part */
570 : : unsigned int na; /* number of keys in the array part */
571 : : unsigned int nums[MAXABITS + 1];
572 : : int i;
573 : : int totaluse;
574 [ + + ]: 564003 : for (i = 0; i <= MAXABITS; i++) nums[i] = 0; /* reset counts */
575 : 17091 : setlimittosize(t);
576 : 17091 : na = numusearray(t, nums); /* count keys in array part */
577 : 17091 : totaluse = na; /* all those keys are integer keys */
578 : 17091 : totaluse += numusehash(t, nums, &na); /* count keys in hash part */
579 : : /* count extra key */
580 [ + + ]: 17091 : if (ttisinteger(ek))
581 : 150 : na += countint(ivalue(ek), nums);
582 : 17091 : totaluse++;
583 : : /* compute new size for array part */
584 : 17091 : asize = computesizes(nums, &na);
585 : : /* resize the table to new computed sizes */
586 : 17091 : luaH_resize(L, t, asize, totaluse - na);
587 : 17091 : }
588 : :
589 : :
590 : :
591 : : /*
592 : : ** }=============================================================
593 : : */
594 : :
595 : :
596 : 16919 : Table *luaH_new (lua_State *L) {
597 : 16919 : GCObject *o = luaC_newobj(L, LUA_VTABLE, sizeof(Table));
598 : 16919 : Table *t = gco2t(o);
599 : 16919 : t->metatable = NULL;
600 : 16919 : t->flags = cast_byte(maskflags); /* table has no metamethod fields */
601 : 16919 : t->array = NULL;
602 : 16919 : t->alimit = 0;
603 : 16919 : setnodevector(L, t, 0);
604 : 16919 : return t;
605 : : }
606 : :
607 : :
608 : 1045 : void luaH_free (lua_State *L, Table *t) {
609 : 1045 : freehash(L, t);
610 : 1045 : luaM_freearray(L, t->array, luaH_realasize(t));
611 : 1045 : luaM_free(L, t);
612 : 1045 : }
613 : :
614 : :
615 : 100813 : static Node *getfreepos (Table *t) {
616 [ + + ]: 100813 : if (!isdummy(t)) {
617 [ + + ]: 173277 : while (t->lastfree > t->node) {
618 : 159453 : t->lastfree--;
619 [ + + ]: 159453 : if (keyisnil(t->lastfree))
620 : 83722 : return t->lastfree;
621 : : }
622 : 13824 : }
623 : 17091 : return NULL; /* could not find a free place */
624 : 100813 : }
625 : :
626 : :
627 : :
628 : : /*
629 : : ** inserts a new key into a hash table; first, check whether key's main
630 : : ** position is free. If not, check whether colliding node is in its main
631 : : ** position or not: if it is not, move colliding node to an empty place and
632 : : ** put new key in its main position; otherwise (colliding node is in its main
633 : : ** position), new key goes to an empty position.
634 : : */
635 : 253646 : TValue *luaH_newkey (lua_State *L, Table *t, const TValue *key) {
636 : : Node *mp;
637 : : TValue aux;
638 [ + - ]: 253646 : if (unlikely(ttisnil(key)))
639 : 0 : luaG_runerror(L, "table index is nil");
640 [ + - ]: 253646 : else if (ttisfloat(key)) {
641 : 0 : lua_Number f = fltvalue(key);
642 : : lua_Integer k;
643 [ # # ]: 0 : if (luaV_flttointeger(f, &k, F2Ieq)) { /* does key fit in an integer? */
644 : 0 : setivalue(&aux, k);
645 : 0 : key = &aux; /* insert it as an integer */
646 : 0 : }
647 [ # # ]: 0 : else if (unlikely(luai_numisnan(f)))
648 : 0 : luaG_runerror(L, "table index is NaN");
649 : 0 : }
650 : 253646 : mp = mainpositionTV(t, key);
651 [ + + + + ]: 253646 : if (!isempty(gval(mp)) || isdummy(t)) { /* main position is taken? */
652 : : Node *othern;
653 : 100813 : Node *f = getfreepos(t); /* get a free place */
654 [ + + ]: 100813 : if (f == NULL) { /* cannot find a free place? */
655 : 17091 : rehash(L, t, key); /* grow table */
656 : : /* whatever called 'newkey' takes care of TM cache */
657 : 17091 : return luaH_set(L, t, key); /* insert key into grown table */
658 : : }
659 : : lua_assert(!isdummy(t));
660 : 83722 : othern = mainposition(t, keytt(mp), &keyval(mp));
661 [ + + ]: 83722 : if (othern != mp) { /* is colliding node out of its main position? */
662 : : /* yes; move colliding node into free position */
663 [ + + ]: 19654 : while (othern + gnext(othern) != mp) /* find previous */
664 : 2997 : othern += gnext(othern);
665 : 16657 : gnext(othern) = cast_int(f - othern); /* rechain to point to 'f' */
666 : 16657 : *f = *mp; /* copy colliding node into free pos. (mp->next also goes) */
667 [ + + ]: 16657 : if (gnext(mp) != 0) {
668 : 2453 : gnext(f) += cast_int(mp - f); /* correct 'next' */
669 : 2453 : gnext(mp) = 0; /* now 'mp' is free */
670 : 2453 : }
671 : 16657 : setempty(gval(mp));
672 : 16657 : }
673 : : else { /* colliding node is in its own main position */
674 : : /* new node will go into free position */
675 [ + + ]: 67065 : if (gnext(mp) != 0)
676 : 13575 : gnext(f) = cast_int((mp + gnext(mp)) - f); /* chain new position */
677 : : else lua_assert(gnext(f) == 0);
678 : 67065 : gnext(mp) = cast_int(f - mp);
679 : 67065 : mp = f;
680 : : }
681 : 83722 : }
682 : 236555 : setnodekey(L, mp, key);
683 [ + + - + : 236555 : luaC_barrierback(L, obj2gco(t), key);
# # ]
684 : : lua_assert(isempty(gval(mp)));
685 : 236555 : return gval(mp);
686 : 253646 : }
687 : :
688 : :
689 : : /*
690 : : ** Search function for integers. If integer is inside 'alimit', get it
691 : : ** directly from the array part. Otherwise, if 'alimit' is not equal to
692 : : ** the real size of the array, key still can be in the array part. In
693 : : ** this case, try to avoid a call to 'luaH_realasize' when key is just
694 : : ** one more than the limit (so that it can be incremented without
695 : : ** changing the real size of the array).
696 : : */
697 : 19127 : const TValue *luaH_getint (Table *t, lua_Integer key) {
698 [ + + ]: 19127 : if (l_castS2U(key) - 1u < t->alimit) /* 'key' in [1, t->alimit]? */
699 : 18929 : return &t->array[key - 1];
700 [ - + # # : 198 : else if (!limitequalsasize(t) && /* key still may be in the array part? */
# # ]
701 [ # # ]: 0 : (l_castS2U(key) == t->alimit + 1 ||
702 : 0 : l_castS2U(key) - 1u < luaH_realasize(t))) {
703 : 0 : t->alimit = cast_uint(key); /* probably '#t' is here now */
704 : 0 : return &t->array[key - 1];
705 : : }
706 : : else {
707 : 198 : Node *n = hashint(t, key);
708 : 198 : for (;;) { /* check whether 'key' is somewhere in the chain */
709 [ - + # # ]: 198 : if (keyisinteger(n) && keyival(n) == key)
710 : 0 : return gval(n); /* that's it */
711 : : else {
712 : 198 : int nx = gnext(n);
713 [ - + ]: 198 : if (nx == 0) break;
714 : 0 : n += nx;
715 : : }
716 : : }
717 : 198 : return &absentkey;
718 : : }
719 : 19127 : }
720 : :
721 : :
722 : : /*
723 : : ** search function for short strings
724 : : */
725 : 304157 : const TValue *luaH_getshortstr (Table *t, TString *key) {
726 : 304157 : Node *n = hashstr(t, key);
727 : : lua_assert(key->tt == LUA_VSHRSTR);
728 : 342345 : for (;;) { /* check whether 'key' is somewhere in the chain */
729 [ + + + + ]: 342345 : if (keyisshrstr(n) && eqshrstr(keystrval(n), key))
730 : 38738 : return gval(n); /* that's it */
731 : : else {
732 : 303607 : int nx = gnext(n);
733 [ + + ]: 303607 : if (nx == 0)
734 : 265419 : return &absentkey; /* not found */
735 : 38188 : n += nx;
736 : : }
737 : : }
738 : 304157 : }
739 : :
740 : :
741 : 196472 : const TValue *luaH_getstr (Table *t, TString *key) {
742 [ + - ]: 196472 : if (key->tt == LUA_VSHRSTR)
743 : 196472 : return luaH_getshortstr(t, key);
744 : : else { /* for long strings, use generic case */
745 : : TValue ko;
746 : 0 : setsvalue(cast(lua_State *, NULL), &ko, key);
747 : 0 : return getgeneric(t, &ko, 0);
748 : : }
749 : 196472 : }
750 : :
751 : :
752 : : /*
753 : : ** main search function
754 : : */
755 : 102140 : const TValue *luaH_get (Table *t, const TValue *key) {
756 [ + + + - : 102140 : switch (ttypetag(key)) {
- ]
757 : 101465 : case LUA_VSHRSTR: return luaH_getshortstr(t, tsvalue(key));
758 : 300 : case LUA_VNUMINT: return luaH_getint(t, ivalue(key));
759 : 0 : case LUA_VNIL: return &absentkey;
760 : : case LUA_VNUMFLT: {
761 : : lua_Integer k;
762 [ # # ]: 0 : if (luaV_flttointeger(fltvalue(key), &k, F2Ieq)) /* integral index? */
763 : 0 : return luaH_getint(t, k); /* use specialized version */
764 : : /* else... */
765 : 0 : } /* FALLTHROUGH */
766 : : default:
767 : 375 : return getgeneric(t, key, 0);
768 : : }
769 : 102140 : }
770 : :
771 : :
772 : : /*
773 : : ** beware: when using this function you probably need to check a GC
774 : : ** barrier and invalidate the TM cache.
775 : : */
776 : 101914 : TValue *luaH_set (lua_State *L, Table *t, const TValue *key) {
777 : 101914 : const TValue *p = luaH_get(t, key);
778 [ + + ]: 101914 : if (!isabstkey(p))
779 : 3459 : return cast(TValue *, p);
780 : 98455 : else return luaH_newkey(L, t, key);
781 : 101914 : }
782 : :
783 : :
784 : 4928 : void luaH_setint (lua_State *L, Table *t, lua_Integer key, TValue *value) {
785 : 4928 : const TValue *p = luaH_getint(t, key);
786 : : TValue *cell;
787 [ + - ]: 4928 : if (!isabstkey(p))
788 : 4928 : cell = cast(TValue *, p);
789 : : else {
790 : : TValue k;
791 : 0 : setivalue(&k, key);
792 : 0 : cell = luaH_newkey(L, t, &k);
793 : : }
794 : 4928 : setobj2t(L, cell, value);
795 : 4928 : }
796 : :
797 : :
798 : : /*
799 : : ** Try to find a boundary in the hash part of table 't'. From the
800 : : ** caller, we know that 'j' is zero or present and that 'j + 1' is
801 : : ** present. We want to find a larger key that is absent from the
802 : : ** table, so that we can do a binary search between the two keys to
803 : : ** find a boundary. We keep doubling 'j' until we get an absent index.
804 : : ** If the doubling would overflow, we try LUA_MAXINTEGER. If it is
805 : : ** absent, we are ready for the binary search. ('j', being max integer,
806 : : ** is larger or equal to 'i', but it cannot be equal because it is
807 : : ** absent while 'i' is present; so 'j > i'.) Otherwise, 'j' is a
808 : : ** boundary. ('j + 1' cannot be a present integer key because it is
809 : : ** not a valid integer in Lua.)
810 : : */
811 : 0 : static lua_Unsigned hash_search (Table *t, lua_Unsigned j) {
812 : : lua_Unsigned i;
813 [ # # ]: 0 : if (j == 0) j++; /* the caller ensures 'j + 1' is present */
814 : 0 : do {
815 : 0 : i = j; /* 'i' is a present index */
816 [ # # ]: 0 : if (j <= l_castS2U(LUA_MAXINTEGER) / 2)
817 : 0 : j *= 2;
818 : : else {
819 : 0 : j = LUA_MAXINTEGER;
820 [ # # ]: 0 : if (isempty(luaH_getint(t, j))) /* t[j] not present? */
821 : 0 : break; /* 'j' now is an absent index */
822 : : else /* weird case */
823 : 0 : return j; /* well, max integer is a boundary... */
824 : : }
825 [ # # ]: 0 : } while (!isempty(luaH_getint(t, j))); /* repeat until an absent t[j] */
826 : : /* i < j && t[i] present && t[j] absent */
827 [ # # ]: 0 : while (j - i > 1u) { /* do a binary search between them */
828 : 0 : lua_Unsigned m = (i + j) / 2;
829 [ # # ]: 0 : if (isempty(luaH_getint(t, m))) j = m;
830 : 0 : else i = m;
831 : : }
832 : 0 : return i;
833 : 0 : }
834 : :
835 : :
836 : 0 : static unsigned int binsearch (const TValue *array, unsigned int i,
837 : : unsigned int j) {
838 [ # # ]: 0 : while (j - i > 1u) { /* binary search */
839 : 0 : unsigned int m = (i + j) / 2;
840 [ # # ]: 0 : if (isempty(&array[m - 1])) j = m;
841 : 0 : else i = m;
842 : : }
843 : 0 : return i;
844 : : }
845 : :
846 : :
847 : : /*
848 : : ** Try to find a boundary in table 't'. (A 'boundary' is an integer index
849 : : ** such that t[i] is present and t[i+1] is absent, or 0 if t[1] is absent
850 : : ** and 'maxinteger' if t[maxinteger] is present.)
851 : : ** (In the next explanation, we use Lua indices, that is, with base 1.
852 : : ** The code itself uses base 0 when indexing the array part of the table.)
853 : : ** The code starts with 'limit = t->alimit', a position in the array
854 : : ** part that may be a boundary.
855 : : **
856 : : ** (1) If 't[limit]' is empty, there must be a boundary before it.
857 : : ** As a common case (e.g., after 't[#t]=nil'), check whether 'limit-1'
858 : : ** is present. If so, it is a boundary. Otherwise, do a binary search
859 : : ** between 0 and limit to find a boundary. In both cases, try to
860 : : ** use this boundary as the new 'alimit', as a hint for the next call.
861 : : **
862 : : ** (2) If 't[limit]' is not empty and the array has more elements
863 : : ** after 'limit', try to find a boundary there. Again, try first
864 : : ** the special case (which should be quite frequent) where 'limit+1'
865 : : ** is empty, so that 'limit' is a boundary. Otherwise, check the
866 : : ** last element of the array part. If it is empty, there must be a
867 : : ** boundary between the old limit (present) and the last element
868 : : ** (absent), which is found with a binary search. (This boundary always
869 : : ** can be a new limit.)
870 : : **
871 : : ** (3) The last case is when there are no elements in the array part
872 : : ** (limit == 0) or its last element (the new limit) is present.
873 : : ** In this case, must check the hash part. If there is no hash part
874 : : ** or 'limit+1' is absent, 'limit' is a boundary. Otherwise, call
875 : : ** 'hash_search' to find a boundary in the hash part of the table.
876 : : ** (In those cases, the boundary is not inside the array part, and
877 : : ** therefore cannot be used as a new limit.)
878 : : */
879 : 148 : lua_Unsigned luaH_getn (Table *t) {
880 : 148 : unsigned int limit = t->alimit;
881 [ + + + + ]: 148 : if (limit > 0 && isempty(&t->array[limit - 1])) { /* (1)? */
882 : : /* there must be a boundary before 'limit' */
883 [ + - - + ]: 25 : if (limit >= 2 && !isempty(&t->array[limit - 2])) {
884 : : /* 'limit - 1' is a boundary; can it be a new limit? */
885 [ + - + - ]: 25 : if (ispow2realasize(t) && !ispow2(limit - 1)) {
886 : 25 : t->alimit = limit - 1;
887 : 25 : setnorealasize(t); /* now 'alimit' is not the real size */
888 : 25 : }
889 : 25 : return limit - 1;
890 : : }
891 : : else { /* must search for a boundary in [0, limit] */
892 : 0 : unsigned int boundary = binsearch(t->array, 0, limit);
893 : : /* can this boundary represent the real size of the array? */
894 [ # # # # ]: 0 : if (ispow2realasize(t) && boundary > luaH_realasize(t) / 2) {
895 : 0 : t->alimit = boundary; /* use it as the new limit */
896 : 0 : setnorealasize(t);
897 : 0 : }
898 : 0 : return boundary;
899 : : }
900 : : }
901 : : /* 'limit' is zero or present in table */
902 [ - + # # ]: 123 : if (!limitequalsasize(t)) { /* (2)? */
903 : : /* 'limit' > 0 and array has more elements after 'limit' */
904 [ # # ]: 0 : if (isempty(&t->array[limit])) /* 'limit + 1' is empty? */
905 : 0 : return limit; /* this is the boundary */
906 : : /* else, try last element in the array */
907 : 0 : limit = luaH_realasize(t);
908 [ # # ]: 0 : if (isempty(&t->array[limit - 1])) { /* empty? */
909 : : /* there must be a boundary in the array after old limit,
910 : : and it must be a valid new limit */
911 : 0 : unsigned int boundary = binsearch(t->array, t->alimit, limit);
912 : 0 : t->alimit = boundary;
913 : 0 : return boundary;
914 : : }
915 : : /* else, new limit is present in the table; check the hash part */
916 : 0 : }
917 : : /* (3) 'limit' is the last element and either is zero or present in table */
918 : : lua_assert(limit == luaH_realasize(t) &&
919 : : (limit == 0 || !isempty(&t->array[limit - 1])));
920 [ + + + - ]: 123 : if (isdummy(t) || isempty(luaH_getint(t, cast(lua_Integer, limit + 1))))
921 : 123 : return limit; /* 'limit + 1' is absent */
922 : : else /* 'limit + 1' is also present */
923 : 0 : return hash_search(t, limit);
924 : 148 : }
925 : :
926 : :
927 : :
928 : : #if defined(LUA_DEBUG)
929 : :
930 : : /* export these functions for the test library */
931 : :
932 : : Node *luaH_mainposition (const Table *t, const TValue *key) {
933 : : return mainpositionTV(t, key);
934 : : }
935 : :
936 : : int luaH_isdummy (const Table *t) { return isdummy(t); }
937 : :
938 : : #endif
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