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							| @ -0,0 +1,670 @@ | ||||
| /* | ||||
| ** $Id: ltable.c,v 2.118 2016/11/07 12:38:35 roberto Exp $ | ||||
| ** Lua tables (hash) | ||||
| ** See Copyright Notice in lua.h | ||||
| */ | ||||
|  | ||||
| #define ltable_c | ||||
| #define LUA_CORE | ||||
|  | ||||
| #include "ltable.h" | ||||
| #include "lprefix.h" | ||||
|  | ||||
| /* | ||||
| ** Implementation of tables (aka arrays, objects, or hash tables). | ||||
| ** Tables keep its elements in two parts: an array part and a hash part. | ||||
| ** Non-negative integer keys are all candidates to be kept in the array | ||||
| ** part. The actual size of the array is the largest 'n' such that | ||||
| ** more than half the slots between 1 and n are in use. | ||||
| ** Hash uses a mix of chained scatter table with Brent's variation. | ||||
| ** A main invariant of these tables is that, if an element is not | ||||
| ** in its main position (i.e. the 'original' position that its hash gives | ||||
| ** to it), then the colliding element is in its own main position. | ||||
| ** Hence even when the load factor reaches 100%, performance remains good. | ||||
| */ | ||||
|  | ||||
| #include <math.h> | ||||
| #include <limits.h> | ||||
|  | ||||
| #include "lua.h" | ||||
| #include "ldebug.h" | ||||
| #include "ldo.h" | ||||
| #include "lgc.h" | ||||
| #include "lmem.h" | ||||
| #include "lobject.h" | ||||
| #include "lstate.h" | ||||
| #include "lstring.h" | ||||
| #include "lvm.h" | ||||
|  | ||||
| namespace NS_SLUA { | ||||
|  | ||||
| /* | ||||
| ** Maximum size of array part (MAXASIZE) is 2^MAXABITS. MAXABITS is | ||||
| ** the largest integer such that MAXASIZE fits in an unsigned int. | ||||
| */ | ||||
| #define MAXABITS	cast_int(sizeof(int) * CHAR_BIT - 1) | ||||
| #define MAXASIZE	(1u << MAXABITS) | ||||
|  | ||||
| /* | ||||
| ** Maximum size of hash part is 2^MAXHBITS. MAXHBITS is the largest | ||||
| ** integer such that 2^MAXHBITS fits in a signed int. (Note that the | ||||
| ** maximum number of elements in a table, 2^MAXABITS + 2^MAXHBITS, still | ||||
| ** fits comfortably in an unsigned int.) | ||||
| */ | ||||
| #define MAXHBITS	(MAXABITS - 1) | ||||
|  | ||||
|  | ||||
| #define hashpow2(t,n)		(gnode(t, lmod((n), sizenode(t)))) | ||||
|  | ||||
| #define hashstr(t,str)		hashpow2(t, (str)->hash) | ||||
| #define hashboolean(t,p)	hashpow2(t, p) | ||||
| #define hashint(t,i)		hashpow2(t, i) | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** for some types, it is better to avoid modulus by power of 2, as | ||||
| ** they tend to have many 2 factors. | ||||
| */ | ||||
| #define hashmod(t,n)	(gnode(t, ((n) % ((sizenode(t)-1)|1)))) | ||||
|  | ||||
|  | ||||
| #define hashpointer(t,p)	hashmod(t, point2uint(p)) | ||||
|  | ||||
|  | ||||
| #define dummynode		(&dummynode_) | ||||
|  | ||||
| static const Node dummynode_ = { | ||||
|   {NILCONSTANT},  /* value */ | ||||
|   {{NILCONSTANT, 0}}  /* key */ | ||||
| }; | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** Hash for floating-point numbers. | ||||
| ** The main computation should be just | ||||
| **     n = frexp(n, &i); return (n * INT_MAX) + i | ||||
| ** but there are some numerical subtleties. | ||||
| ** In a two-complement representation, INT_MAX does not has an exact | ||||
| ** representation as a float, but INT_MIN does; because the absolute | ||||
| ** value of 'frexp' is smaller than 1 (unless 'n' is inf/NaN), the | ||||
| ** absolute value of the product 'frexp * -INT_MIN' is smaller or equal | ||||
| ** to INT_MAX. Next, the use of 'unsigned int' avoids overflows when | ||||
| ** adding 'i'; the use of '~u' (instead of '-u') avoids problems with | ||||
| ** INT_MIN. | ||||
| */ | ||||
| #if !defined(l_hashfloat) | ||||
| static int l_hashfloat (lua_Number n) { | ||||
|   int i; | ||||
|   lua_Integer ni; | ||||
|   n = l_mathop(frexp)(n, &i) * -cast_num(INT_MIN); | ||||
|   if (!lua_numbertointeger(n, &ni)) {  /* is 'n' inf/-inf/NaN? */ | ||||
|     lua_assert(luai_numisnan(n) || l_mathop(fabs)(n) == cast_num(HUGE_VAL)); | ||||
|     return 0; | ||||
|   } | ||||
|   else {  /* normal case */ | ||||
|     unsigned int u = cast(unsigned int, i) + cast(unsigned int, ni); | ||||
|     return cast_int(u <= cast(unsigned int, INT_MAX) ? u : ~u); | ||||
|   } | ||||
| } | ||||
| #endif | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** returns the 'main' position of an element in a table (that is, the index | ||||
| ** of its hash value) | ||||
| */ | ||||
| static Node *mainposition (const Table *t, const TValue *key) { | ||||
|   switch (ttype(key)) { | ||||
|     case LUA_TNUMINT: | ||||
|       return hashint(t, ivalue(key)); | ||||
|     case LUA_TNUMFLT: | ||||
|       return hashmod(t, l_hashfloat(fltvalue(key))); | ||||
|     case LUA_TSHRSTR: | ||||
|       return hashstr(t, tsvalue(key)); | ||||
|     case LUA_TLNGSTR: | ||||
|       return hashpow2(t, luaS_hashlongstr(tsvalue(key))); | ||||
|     case LUA_TBOOLEAN: | ||||
|       return hashboolean(t, bvalue(key)); | ||||
|     case LUA_TLIGHTUSERDATA: | ||||
|       return hashpointer(t, pvalue(key)); | ||||
|     case LUA_TLCF: | ||||
|       return hashpointer(t, fvalue(key)); | ||||
|     default: | ||||
|       lua_assert(!ttisdeadkey(key)); | ||||
|       return hashpointer(t, gcvalue(key)); | ||||
|   } | ||||
| } | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** returns the index for 'key' if 'key' is an appropriate key to live in | ||||
| ** the array part of the table, 0 otherwise. | ||||
| */ | ||||
| static unsigned int arrayindex (const TValue *key) { | ||||
|   if (ttisinteger(key)) { | ||||
|     lua_Integer k = ivalue(key); | ||||
|     if (0 < k && (lua_Unsigned)k <= MAXASIZE) | ||||
|       return cast(unsigned int, k);  /* 'key' is an appropriate array index */ | ||||
|   } | ||||
|   return 0;  /* 'key' did not match some condition */ | ||||
| } | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** returns the index of a 'key' for table traversals. First goes all | ||||
| ** elements in the array part, then elements in the hash part. The | ||||
| ** beginning of a traversal is signaled by 0. | ||||
| */ | ||||
| static unsigned int findindex (lua_State *L, Table *t, StkId key) { | ||||
|   unsigned int i; | ||||
|   if (ttisnil(key)) return 0;  /* first iteration */ | ||||
|   i = arrayindex(key); | ||||
|   if (i != 0 && i <= t->sizearray)  /* is 'key' inside array part? */ | ||||
|     return i;  /* yes; that's the index */ | ||||
|   else { | ||||
|     int nx; | ||||
|     Node *n = mainposition(t, key); | ||||
|     for (;;) {  /* check whether 'key' is somewhere in the chain */ | ||||
|       /* key may be dead already, but it is ok to use it in 'next' */ | ||||
|       if (luaV_rawequalobj(gkey(n), key) || | ||||
|             (ttisdeadkey(gkey(n)) && iscollectable(key) && | ||||
|              deadvalue(gkey(n)) == gcvalue(key))) { | ||||
|         i = cast_int(n - gnode(t, 0));  /* key index in hash table */ | ||||
|         /* hash elements are numbered after array ones */ | ||||
|         return (i + 1) + t->sizearray; | ||||
|       } | ||||
|       nx = gnext(n); | ||||
|       if (nx == 0) | ||||
|         luaG_runerror(L, "invalid key to 'next'");  /* key not found */ | ||||
|       else n += nx; | ||||
|     } | ||||
|   } | ||||
| } | ||||
|  | ||||
|  | ||||
| int luaH_next (lua_State *L, Table *t, StkId key) { | ||||
|   unsigned int i = findindex(L, t, key);  /* find original element */ | ||||
|   for (; i < t->sizearray; i++) {  /* try first array part */ | ||||
|     if (!ttisnil(&t->array[i])) {  /* a non-nil value? */ | ||||
|       setivalue(key, i + 1); | ||||
|       setobj2s(L, key+1, &t->array[i]); | ||||
|       return 1; | ||||
|     } | ||||
|   } | ||||
|   for (i -= t->sizearray; cast_int(i) < sizenode(t); i++) {  /* hash part */ | ||||
|     if (!ttisnil(gval(gnode(t, i)))) {  /* a non-nil value? */ | ||||
|       setobj2s(L, key, gkey(gnode(t, i))); | ||||
|       setobj2s(L, key+1, gval(gnode(t, i))); | ||||
|       return 1; | ||||
|     } | ||||
|   } | ||||
|   return 0;  /* no more elements */ | ||||
| } | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** {============================================================= | ||||
| ** Rehash | ||||
| ** ============================================================== | ||||
| */ | ||||
|  | ||||
| /* | ||||
| ** Compute the optimal size for the array part of table 't'. 'nums' is a | ||||
| ** "count array" where 'nums[i]' is the number of integers in the table | ||||
| ** between 2^(i - 1) + 1 and 2^i. 'pna' enters with the total number of | ||||
| ** integer keys in the table and leaves with the number of keys that | ||||
| ** will go to the array part; return the optimal size. | ||||
| */ | ||||
| static unsigned int computesizes (unsigned int nums[], unsigned int *pna) { | ||||
|   int i; | ||||
|   unsigned int twotoi;  /* 2^i (candidate for optimal size) */ | ||||
|   unsigned int a = 0;  /* number of elements smaller than 2^i */ | ||||
|   unsigned int na = 0;  /* number of elements to go to array part */ | ||||
|   unsigned int optimal = 0;  /* optimal size for array part */ | ||||
|   /* loop while keys can fill more than half of total size */ | ||||
|   for (i = 0, twotoi = 1; *pna > twotoi / 2; i++, twotoi *= 2) { | ||||
|     if (nums[i] > 0) { | ||||
|       a += nums[i]; | ||||
|       if (a > twotoi/2) {  /* more than half elements present? */ | ||||
|         optimal = twotoi;  /* optimal size (till now) */ | ||||
|         na = a;  /* all elements up to 'optimal' will go to array part */ | ||||
|       } | ||||
|     } | ||||
|   } | ||||
|   lua_assert((optimal == 0 || optimal / 2 < na) && na <= optimal); | ||||
|   *pna = na; | ||||
|   return optimal; | ||||
| } | ||||
|  | ||||
|  | ||||
| static int countint (const TValue *key, unsigned int *nums) { | ||||
|   unsigned int k = arrayindex(key); | ||||
|   if (k != 0) {  /* is 'key' an appropriate array index? */ | ||||
|     nums[luaO_ceillog2(k)]++;  /* count as such */ | ||||
|     return 1; | ||||
|   } | ||||
|   else | ||||
|     return 0; | ||||
| } | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** Count keys in array part of table 't': Fill 'nums[i]' with | ||||
| ** number of keys that will go into corresponding slice and return | ||||
| ** total number of non-nil keys. | ||||
| */ | ||||
| static unsigned int numusearray (const Table *t, unsigned int *nums) { | ||||
|   int lg; | ||||
|   unsigned int ttlg;  /* 2^lg */ | ||||
|   unsigned int ause = 0;  /* summation of 'nums' */ | ||||
|   unsigned int i = 1;  /* count to traverse all array keys */ | ||||
|   /* traverse each slice */ | ||||
|   for (lg = 0, ttlg = 1; lg <= MAXABITS; lg++, ttlg *= 2) { | ||||
|     unsigned int lc = 0;  /* counter */ | ||||
|     unsigned int lim = ttlg; | ||||
|     if (lim > t->sizearray) { | ||||
|       lim = t->sizearray;  /* adjust upper limit */ | ||||
|       if (i > lim) | ||||
|         break;  /* no more elements to count */ | ||||
|     } | ||||
|     /* count elements in range (2^(lg - 1), 2^lg] */ | ||||
|     for (; i <= lim; i++) { | ||||
|       if (!ttisnil(&t->array[i-1])) | ||||
|         lc++; | ||||
|     } | ||||
|     nums[lg] += lc; | ||||
|     ause += lc; | ||||
|   } | ||||
|   return ause; | ||||
| } | ||||
|  | ||||
|  | ||||
| static int numusehash (const Table *t, unsigned int *nums, unsigned int *pna) { | ||||
|   int totaluse = 0;  /* total number of elements */ | ||||
|   int ause = 0;  /* elements added to 'nums' (can go to array part) */ | ||||
|   int i = sizenode(t); | ||||
|   while (i--) { | ||||
|     Node *n = &t->node[i]; | ||||
|     if (!ttisnil(gval(n))) { | ||||
|       ause += countint(gkey(n), nums); | ||||
|       totaluse++; | ||||
|     } | ||||
|   } | ||||
|   *pna += ause; | ||||
|   return totaluse; | ||||
| } | ||||
|  | ||||
|  | ||||
| static void setarrayvector (lua_State *L, Table *t, unsigned int size) { | ||||
|   unsigned int i; | ||||
|   luaM_reallocvector(L, t->array, t->sizearray, size, TValue); | ||||
|   for (i=t->sizearray; i<size; i++) | ||||
|      setnilvalue(&t->array[i]); | ||||
|   t->sizearray = size; | ||||
| } | ||||
|  | ||||
|  | ||||
| static void setnodevector (lua_State *L, Table *t, unsigned int size) { | ||||
|   if (size == 0) {  /* no elements to hash part? */ | ||||
|     t->node = cast(Node *, dummynode);  /* use common 'dummynode' */ | ||||
|     t->lsizenode = 0; | ||||
|     t->lastfree = NULL;  /* signal that it is using dummy node */ | ||||
|   } | ||||
|   else { | ||||
|     int i; | ||||
|     int lsize = luaO_ceillog2(size); | ||||
|     if (lsize > MAXHBITS) | ||||
|       luaG_runerror(L, "table overflow"); | ||||
|     size = twoto(lsize); | ||||
|     t->node = luaM_newvector(L, size, Node); | ||||
|     for (i = 0; i < (int)size; i++) { | ||||
|       Node *n = gnode(t, i); | ||||
|       gnext(n) = 0; | ||||
|       setnilvalue(wgkey(n)); | ||||
|       setnilvalue(gval(n)); | ||||
|     } | ||||
|     t->lsizenode = cast_byte(lsize); | ||||
|     t->lastfree = gnode(t, size);  /* all positions are free */ | ||||
|   } | ||||
| } | ||||
|  | ||||
|  | ||||
| void luaH_resize (lua_State *L, Table *t, unsigned int nasize, | ||||
|                                           unsigned int nhsize) { | ||||
|   unsigned int i; | ||||
|   int j; | ||||
|   unsigned int oldasize = t->sizearray; | ||||
|   int oldhsize = allocsizenode(t); | ||||
|   Node *nold = t->node;  /* save old hash ... */ | ||||
|   if (nasize > oldasize)  /* array part must grow? */ | ||||
|     setarrayvector(L, t, nasize); | ||||
|   /* create new hash part with appropriate size */ | ||||
|   setnodevector(L, t, nhsize); | ||||
|   if (nasize < oldasize) {  /* array part must shrink? */ | ||||
|     t->sizearray = nasize; | ||||
|     /* re-insert elements from vanishing slice */ | ||||
|     for (i=nasize; i<oldasize; i++) { | ||||
|       if (!ttisnil(&t->array[i])) | ||||
|         luaH_setint(L, t, i + 1, &t->array[i]); | ||||
|     } | ||||
|     /* shrink array */ | ||||
|     luaM_reallocvector(L, t->array, oldasize, nasize, TValue); | ||||
|   } | ||||
|   /* re-insert elements from hash part */ | ||||
|   for (j = oldhsize - 1; j >= 0; j--) { | ||||
|     Node *old = nold + j; | ||||
|     if (!ttisnil(gval(old))) { | ||||
|       /* doesn't need barrier/invalidate cache, as entry was | ||||
|          already present in the table */ | ||||
|       setobjt2t(L, luaH_set(L, t, gkey(old)), gval(old)); | ||||
|     } | ||||
|   } | ||||
|   if (oldhsize > 0)  /* not the dummy node? */ | ||||
|     luaM_freearray(L, nold, cast(size_t, oldhsize)); /* free old hash */ | ||||
| } | ||||
|  | ||||
|  | ||||
| void luaH_resizearray (lua_State *L, Table *t, unsigned int nasize) { | ||||
|   int nsize = allocsizenode(t); | ||||
|   luaH_resize(L, t, nasize, nsize); | ||||
| } | ||||
|  | ||||
| /* | ||||
| ** nums[i] = number of keys 'k' where 2^(i - 1) < k <= 2^i | ||||
| */ | ||||
| static void rehash (lua_State *L, Table *t, const TValue *ek) { | ||||
|   unsigned int asize;  /* optimal size for array part */ | ||||
|   unsigned int na;  /* number of keys in the array part */ | ||||
|   unsigned int nums[MAXABITS + 1]; | ||||
|   int i; | ||||
|   int totaluse; | ||||
|   for (i = 0; i <= MAXABITS; i++) nums[i] = 0;  /* reset counts */ | ||||
|   na = numusearray(t, nums);  /* count keys in array part */ | ||||
|   totaluse = na;  /* all those keys are integer keys */ | ||||
|   totaluse += numusehash(t, nums, &na);  /* count keys in hash part */ | ||||
|   /* count extra key */ | ||||
|   na += countint(ek, nums); | ||||
|   totaluse++; | ||||
|   /* compute new size for array part */ | ||||
|   asize = computesizes(nums, &na); | ||||
|   /* resize the table to new computed sizes */ | ||||
|   luaH_resize(L, t, asize, totaluse - na); | ||||
| } | ||||
|  | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** }============================================================= | ||||
| */ | ||||
|  | ||||
|  | ||||
| Table *luaH_new (lua_State *L) { | ||||
|   GCObject *o = luaC_newobj(L, LUA_TTABLE, sizeof(Table)); | ||||
|   Table *t = gco2t(o); | ||||
|   t->metatable = NULL; | ||||
|   t->flags = cast_byte(~0); | ||||
|   t->array = NULL; | ||||
|   t->sizearray = 0; | ||||
|   setnodevector(L, t, 0); | ||||
|   return t; | ||||
| } | ||||
|  | ||||
|  | ||||
| void luaH_free (lua_State *L, Table *t) { | ||||
|   if (!isdummy(t)) | ||||
|     luaM_freearray(L, t->node, cast(size_t, sizenode(t))); | ||||
|   luaM_freearray(L, t->array, t->sizearray); | ||||
|   luaM_free(L, t); | ||||
| } | ||||
|  | ||||
|  | ||||
| static Node *getfreepos (Table *t) { | ||||
|   if (!isdummy(t)) { | ||||
|     while (t->lastfree > t->node) { | ||||
|       t->lastfree--; | ||||
|       if (ttisnil(gkey(t->lastfree))) | ||||
|         return t->lastfree; | ||||
|     } | ||||
|   } | ||||
|   return NULL;  /* could not find a free place */ | ||||
| } | ||||
|  | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** inserts a new key into a hash table; first, check whether key's main | ||||
| ** position is free. If not, check whether colliding node is in its main | ||||
| ** position or not: if it is not, move colliding node to an empty place and | ||||
| ** put new key in its main position; otherwise (colliding node is in its main | ||||
| ** position), new key goes to an empty position. | ||||
| */ | ||||
| TValue *luaH_newkey (lua_State *L, Table *t, const TValue *key) { | ||||
|   Node *mp; | ||||
|   TValue aux; | ||||
|   if (ttisnil(key)) luaG_runerror(L, "table index is nil"); | ||||
|   else if (ttisfloat(key)) { | ||||
|     lua_Integer k; | ||||
|     if (luaV_tointeger(key, &k, 0)) {  /* does index fit in an integer? */ | ||||
|       setivalue(&aux, k); | ||||
|       key = &aux;  /* insert it as an integer */ | ||||
|     } | ||||
|     else if (luai_numisnan(fltvalue(key))) | ||||
|       luaG_runerror(L, "table index is NaN"); | ||||
|   } | ||||
|   mp = mainposition(t, key); | ||||
|   if (!ttisnil(gval(mp)) || isdummy(t)) {  /* main position is taken? */ | ||||
|     Node *othern; | ||||
|     Node *f = getfreepos(t);  /* get a free place */ | ||||
|     if (f == NULL) {  /* cannot find a free place? */ | ||||
|       rehash(L, t, key);  /* grow table */ | ||||
|       /* whatever called 'newkey' takes care of TM cache */ | ||||
|       return luaH_set(L, t, key);  /* insert key into grown table */ | ||||
|     } | ||||
|     lua_assert(!isdummy(t)); | ||||
|     othern = mainposition(t, gkey(mp)); | ||||
|     if (othern != mp) {  /* is colliding node out of its main position? */ | ||||
|       /* yes; move colliding node into free position */ | ||||
|       while (othern + gnext(othern) != mp)  /* find previous */ | ||||
|         othern += gnext(othern); | ||||
|       gnext(othern) = cast_int(f - othern);  /* rechain to point to 'f' */ | ||||
|       *f = *mp;  /* copy colliding node into free pos. (mp->next also goes) */ | ||||
|       if (gnext(mp) != 0) { | ||||
|         gnext(f) += cast_int(mp - f);  /* correct 'next' */ | ||||
|         gnext(mp) = 0;  /* now 'mp' is free */ | ||||
|       } | ||||
|       setnilvalue(gval(mp)); | ||||
|     } | ||||
|     else {  /* colliding node is in its own main position */ | ||||
|       /* new node will go into free position */ | ||||
|       if (gnext(mp) != 0) | ||||
|         gnext(f) = cast_int((mp + gnext(mp)) - f);  /* chain new position */ | ||||
|       else lua_assert(gnext(f) == 0); | ||||
|       gnext(mp) = cast_int(f - mp); | ||||
|       mp = f; | ||||
|     } | ||||
|   } | ||||
|   setnodekey(L, &mp->i_key, key); | ||||
|   luaC_barrierback(L, t, key); | ||||
|   lua_assert(ttisnil(gval(mp))); | ||||
|   return gval(mp); | ||||
| } | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** search function for integers | ||||
| */ | ||||
| const TValue *luaH_getint (Table *t, lua_Integer key) { | ||||
|   /* (1 <= key && key <= t->sizearray) */ | ||||
|   if (l_castS2U(key) - 1 < t->sizearray) | ||||
|     return &t->array[key - 1]; | ||||
|   else { | ||||
|     Node *n = hashint(t, key); | ||||
|     for (;;) {  /* check whether 'key' is somewhere in the chain */ | ||||
|       if (ttisinteger(gkey(n)) && ivalue(gkey(n)) == key) | ||||
|         return gval(n);  /* that's it */ | ||||
|       else { | ||||
|         int nx = gnext(n); | ||||
|         if (nx == 0) break; | ||||
|         n += nx; | ||||
|       } | ||||
|     } | ||||
|     return luaO_nilobject; | ||||
|   } | ||||
| } | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** search function for short strings | ||||
| */ | ||||
| const TValue *luaH_getshortstr (Table *t, TString *key) { | ||||
|   Node *n = hashstr(t, key); | ||||
|   lua_assert(key->tt == LUA_TSHRSTR); | ||||
|   for (;;) {  /* check whether 'key' is somewhere in the chain */ | ||||
|     const TValue *k = gkey(n); | ||||
|     if (ttisshrstring(k) && eqshrstr(tsvalue(k), key)) | ||||
|       return gval(n);  /* that's it */ | ||||
|     else { | ||||
|       int nx = gnext(n); | ||||
|       if (nx == 0) | ||||
|         return luaO_nilobject;  /* not found */ | ||||
|       n += nx; | ||||
|     } | ||||
|   } | ||||
| } | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** "Generic" get version. (Not that generic: not valid for integers, | ||||
| ** which may be in array part, nor for floats with integral values.) | ||||
| */ | ||||
| static const TValue *getgeneric (Table *t, const TValue *key) { | ||||
|   Node *n = mainposition(t, key); | ||||
|   for (;;) {  /* check whether 'key' is somewhere in the chain */ | ||||
|     if (luaV_rawequalobj(gkey(n), key)) | ||||
|       return gval(n);  /* that's it */ | ||||
|     else { | ||||
|       int nx = gnext(n); | ||||
|       if (nx == 0) | ||||
|         return luaO_nilobject;  /* not found */ | ||||
|       n += nx; | ||||
|     } | ||||
|   } | ||||
| } | ||||
|  | ||||
|  | ||||
| const TValue *luaH_getstr (Table *t, TString *key) { | ||||
|   if (key->tt == LUA_TSHRSTR) | ||||
|     return luaH_getshortstr(t, key); | ||||
|   else {  /* for long strings, use generic case */ | ||||
|     TValue ko; | ||||
|     setsvalue(cast(lua_State *, NULL), &ko, key); | ||||
|     return getgeneric(t, &ko); | ||||
|   } | ||||
| } | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** main search function | ||||
| */ | ||||
| const TValue *luaH_get (Table *t, const TValue *key) { | ||||
|   switch (ttype(key)) { | ||||
|     case LUA_TSHRSTR: return luaH_getshortstr(t, tsvalue(key)); | ||||
|     case LUA_TNUMINT: return luaH_getint(t, ivalue(key)); | ||||
|     case LUA_TNIL: return luaO_nilobject; | ||||
|     case LUA_TNUMFLT: { | ||||
|       lua_Integer k; | ||||
|       if (luaV_tointeger(key, &k, 0)) /* index is int? */ | ||||
|         return luaH_getint(t, k);  /* use specialized version */ | ||||
|       /* else... */ | ||||
|     }  /* FALLTHROUGH */ | ||||
|     default: | ||||
|       return getgeneric(t, key); | ||||
|   } | ||||
| } | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** beware: when using this function you probably need to check a GC | ||||
| ** barrier and invalidate the TM cache. | ||||
| */ | ||||
| TValue *luaH_set (lua_State *L, Table *t, const TValue *key) { | ||||
|   const TValue *p = luaH_get(t, key); | ||||
|   if (p != luaO_nilobject) | ||||
|     return cast(TValue *, p); | ||||
|   else return luaH_newkey(L, t, key); | ||||
| } | ||||
|  | ||||
|  | ||||
| void luaH_setint (lua_State *L, Table *t, lua_Integer key, TValue *value) { | ||||
|   const TValue *p = luaH_getint(t, key); | ||||
|   TValue *cell; | ||||
|   if (p != luaO_nilobject) | ||||
|     cell = cast(TValue *, p); | ||||
|   else { | ||||
|     TValue k; | ||||
|     setivalue(&k, key); | ||||
|     cell = luaH_newkey(L, t, &k); | ||||
|   } | ||||
|   setobj2t(L, cell, value); | ||||
| } | ||||
|  | ||||
|  | ||||
| static int unbound_search (Table *t, unsigned int j) { | ||||
|   unsigned int i = j;  /* i is zero or a present index */ | ||||
|   j++; | ||||
|   /* find 'i' and 'j' such that i is present and j is not */ | ||||
|   while (!ttisnil(luaH_getint(t, j))) { | ||||
|     i = j; | ||||
|     if (j > cast(unsigned int, MAX_INT)/2) {  /* overflow? */ | ||||
|       /* table was built with bad purposes: resort to linear search */ | ||||
|       i = 1; | ||||
|       while (!ttisnil(luaH_getint(t, i))) i++; | ||||
|       return i - 1; | ||||
|     } | ||||
|     j *= 2; | ||||
|   } | ||||
|   /* now do a binary search between them */ | ||||
|   while (j - i > 1) { | ||||
|     unsigned int m = (i+j)/2; | ||||
|     if (ttisnil(luaH_getint(t, m))) j = m; | ||||
|     else i = m; | ||||
|   } | ||||
|   return i; | ||||
| } | ||||
|  | ||||
|  | ||||
| /* | ||||
| ** Try to find a boundary in table 't'. A 'boundary' is an integer index | ||||
| ** such that t[i] is non-nil and t[i+1] is nil (and 0 if t[1] is nil). | ||||
| */ | ||||
| int luaH_getn (Table *t) { | ||||
|   unsigned int j = t->sizearray; | ||||
|   if (j > 0 && ttisnil(&t->array[j - 1])) { | ||||
|     /* there is a boundary in the array part: (binary) search for it */ | ||||
|     unsigned int i = 0; | ||||
|     while (j - i > 1) { | ||||
|       unsigned int m = (i+j)/2; | ||||
|       if (ttisnil(&t->array[m - 1])) j = m; | ||||
|       else i = m; | ||||
|     } | ||||
|     return i; | ||||
|   } | ||||
|   /* else must find a boundary in hash part */ | ||||
|   else if (isdummy(t))  /* hash part is empty? */ | ||||
|     return j;  /* that is easy... */ | ||||
|   else return unbound_search(t, j); | ||||
| } | ||||
|  | ||||
|  | ||||
|  | ||||
| #if defined(LUA_DEBUG) | ||||
|  | ||||
| Node *luaH_mainposition (const Table *t, const TValue *key) { | ||||
|   return mainposition(t, key); | ||||
| } | ||||
|  | ||||
| int luaH_isdummy (const Table *t) { return isdummy(t); } | ||||
|  | ||||
| #endif | ||||
|  | ||||
| } // end NS_SLUA | ||||
		Reference in New Issue
	
	Block a user