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Aegisub/subprojects/luajit/src/lj_tab.c

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/*
** Table handling.
** Copyright (C) 2005-2017 Mike Pall. See Copyright Notice in luajit.h
**
** Major portions taken verbatim or adapted from the Lua interpreter.
** Copyright (C) 1994-2008 Lua.org, PUC-Rio. See Copyright Notice in lua.h
*/
#define lj_tab_c
#define LUA_CORE
#include "lj_obj.h"
#include "lj_gc.h"
#include "lj_err.h"
#include "lj_tab.h"
/* -- Object hashing ------------------------------------------------------ */
/* Hash values are masked with the table hash mask and used as an index. */
static LJ_AINLINE Node *hashmask(const GCtab *t, uint32_t hash)
{
Node *n = noderef(t->node);
return &n[hash & t->hmask];
}
/* String hashes are precomputed when they are interned. */
#define hashstr(t, s) hashmask(t, (s)->hash)
#define hashlohi(t, lo, hi) hashmask((t), hashrot((lo), (hi)))
#define hashnum(t, o) hashlohi((t), (o)->u32.lo, ((o)->u32.hi << 1))
#define hashptr(t, p) hashlohi((t), u32ptr(p), u32ptr(p) + HASH_BIAS)
#define hashgcref(t, r) hashlohi((t), gcrefu(r), gcrefu(r) + HASH_BIAS)
/* Hash an arbitrary key and return its anchor position in the hash table. */
static Node *hashkey(const GCtab *t, cTValue *key)
{
lua_assert(!tvisint(key));
if (tvisstr(key))
return hashstr(t, strV(key));
else if (tvisnum(key))
return hashnum(t, key);
else if (tvisbool(key))
return hashmask(t, boolV(key));
else
return hashgcref(t, key->gcr);
/* Only hash 32 bits of lightuserdata on a 64 bit CPU. Good enough? */
}
/* -- Table creation and destruction -------------------------------------- */
/* Create new hash part for table. */
static LJ_AINLINE void newhpart(lua_State *L, GCtab *t, uint32_t hbits)
{
uint32_t hsize;
Node *node;
lua_assert(hbits != 0);
if (hbits > LJ_MAX_HBITS)
lj_err_msg(L, LJ_ERR_TABOV);
hsize = 1u << hbits;
node = lj_mem_newvec(L, hsize, Node);
setmref(node->freetop, &node[hsize]);
setmref(t->node, node);
t->hmask = hsize-1;
}
/*
** Q: Why all of these copies of t->hmask, t->node etc. to local variables?
** A: Because alias analysis for C is _really_ tough.
** Even state-of-the-art C compilers won't produce good code without this.
*/
/* Clear hash part of table. */
static LJ_AINLINE void clearhpart(GCtab *t)
{
uint32_t i, hmask = t->hmask;
Node *node = noderef(t->node);
lua_assert(t->hmask != 0);
for (i = 0; i <= hmask; i++) {
Node *n = &node[i];
setmref(n->next, NULL);
setnilV(&n->key);
setnilV(&n->val);
}
}
/* Clear array part of table. */
static LJ_AINLINE void clearapart(GCtab *t)
{
uint32_t i, asize = t->asize;
TValue *array = tvref(t->array);
for (i = 0; i < asize; i++)
setnilV(&array[i]);
}
/* Create a new table. Note: the slots are not initialized (yet). */
static GCtab *newtab(lua_State *L, uint32_t asize, uint32_t hbits)
{
GCtab *t;
/* First try to colocate the array part. */
if (LJ_MAX_COLOSIZE != 0 && asize > 0 && asize <= LJ_MAX_COLOSIZE) {
lua_assert((sizeof(GCtab) & 7) == 0);
t = (GCtab *)lj_mem_newgco(L, sizetabcolo(asize));
t->gct = ~LJ_TTAB;
t->nomm = (uint8_t)~0;
t->colo = (int8_t)asize;
setmref(t->array, (TValue *)((char *)t + sizeof(GCtab)));
setgcrefnull(t->metatable);
t->asize = asize;
t->hmask = 0;
setmref(t->node, &G(L)->nilnode);
} else { /* Otherwise separately allocate the array part. */
t = lj_mem_newobj(L, GCtab);
t->gct = ~LJ_TTAB;
t->nomm = (uint8_t)~0;
t->colo = 0;
setmref(t->array, NULL);
setgcrefnull(t->metatable);
t->asize = 0; /* In case the array allocation fails. */
t->hmask = 0;
setmref(t->node, &G(L)->nilnode);
if (asize > 0) {
if (asize > LJ_MAX_ASIZE)
lj_err_msg(L, LJ_ERR_TABOV);
setmref(t->array, lj_mem_newvec(L, asize, TValue));
t->asize = asize;
}
}
if (hbits)
newhpart(L, t, hbits);
return t;
}
/* Create a new table.
**
** IMPORTANT NOTE: The API differs from lua_createtable()!
**
** The array size is non-inclusive. E.g. asize=128 creates array slots
** for 0..127, but not for 128. If you need slots 1..128, pass asize=129
** (slot 0 is wasted in this case).
**
** The hash size is given in hash bits. hbits=0 means no hash part.
** hbits=1 creates 2 hash slots, hbits=2 creates 4 hash slots and so on.
*/
GCtab *lj_tab_new(lua_State *L, uint32_t asize, uint32_t hbits)
{
GCtab *t = newtab(L, asize, hbits);
clearapart(t);
if (t->hmask > 0) clearhpart(t);
return t;
}
#if LJ_HASJIT
GCtab * LJ_FASTCALL lj_tab_new1(lua_State *L, uint32_t ahsize)
{
GCtab *t = newtab(L, ahsize & 0xffffff, ahsize >> 24);
clearapart(t);
if (t->hmask > 0) clearhpart(t);
return t;
}
#endif
/* Duplicate a table. */
GCtab * LJ_FASTCALL lj_tab_dup(lua_State *L, const GCtab *kt)
{
GCtab *t;
uint32_t asize, hmask;
t = newtab(L, kt->asize, kt->hmask > 0 ? lj_fls(kt->hmask)+1 : 0);
lua_assert(kt->asize == t->asize && kt->hmask == t->hmask);
t->nomm = 0; /* Keys with metamethod names may be present. */
asize = kt->asize;
if (asize > 0) {
TValue *array = tvref(t->array);
TValue *karray = tvref(kt->array);
if (asize < 64) { /* An inlined loop beats memcpy for < 512 bytes. */
uint32_t i;
for (i = 0; i < asize; i++)
copyTV(L, &array[i], &karray[i]);
} else {
memcpy(array, karray, asize*sizeof(TValue));
}
}
hmask = kt->hmask;
if (hmask > 0) {
uint32_t i;
Node *node = noderef(t->node);
Node *knode = noderef(kt->node);
ptrdiff_t d = (char *)node - (char *)knode;
setmref(node->freetop, (Node *)((char *)noderef(knode->freetop) + d));
for (i = 0; i <= hmask; i++) {
Node *kn = &knode[i];
Node *n = &node[i];
Node *next = nextnode(kn);
/* Don't use copyTV here, since it asserts on a copy of a dead key. */
n->val = kn->val; n->key = kn->key;
setmref(n->next, next == NULL? next : (Node *)((char *)next + d));
}
}
return t;
}
/* Free a table. */
void LJ_FASTCALL lj_tab_free(global_State *g, GCtab *t)
{
if (t->hmask > 0)
lj_mem_freevec(g, noderef(t->node), t->hmask+1, Node);
if (t->asize > 0 && LJ_MAX_COLOSIZE != 0 && t->colo <= 0)
lj_mem_freevec(g, tvref(t->array), t->asize, TValue);
if (LJ_MAX_COLOSIZE != 0 && t->colo)
lj_mem_free(g, t, sizetabcolo((uint32_t)t->colo & 0x7f));
else
lj_mem_freet(g, t);
}
/* -- Table resizing ------------------------------------------------------ */
/* Resize a table to fit the new array/hash part sizes. */
static void resizetab(lua_State *L, GCtab *t, uint32_t asize, uint32_t hbits)
{
Node *oldnode = noderef(t->node);
uint32_t oldasize = t->asize;
uint32_t oldhmask = t->hmask;
if (asize > oldasize) { /* Array part grows? */
TValue *array;
uint32_t i;
if (asize > LJ_MAX_ASIZE)
lj_err_msg(L, LJ_ERR_TABOV);
if (LJ_MAX_COLOSIZE != 0 && t->colo > 0) {
/* A colocated array must be separated and copied. */
TValue *oarray = tvref(t->array);
array = lj_mem_newvec(L, asize, TValue);
t->colo = (int8_t)(t->colo | 0x80); /* Mark as separated (colo < 0). */
for (i = 0; i < oldasize; i++)
copyTV(L, &array[i], &oarray[i]);
} else {
array = (TValue *)lj_mem_realloc(L, tvref(t->array),
oldasize*sizeof(TValue), asize*sizeof(TValue));
}
setmref(t->array, array);
t->asize = asize;
for (i = oldasize; i < asize; i++) /* Clear newly allocated slots. */
setnilV(&array[i]);
}
/* Create new (empty) hash part. */
if (hbits) {
newhpart(L, t, hbits);
clearhpart(t);
} else {
global_State *g = G(L);
setmref(t->node, &g->nilnode);
t->hmask = 0;
}
if (asize < oldasize) { /* Array part shrinks? */
TValue *array = tvref(t->array);
uint32_t i;
t->asize = asize; /* Note: This 'shrinks' even colocated arrays. */
for (i = asize; i < oldasize; i++) /* Reinsert old array values. */
if (!tvisnil(&array[i]))
copyTV(L, lj_tab_setinth(L, t, (int32_t)i), &array[i]);
/* Physically shrink only separated arrays. */
if (LJ_MAX_COLOSIZE != 0 && t->colo <= 0)
setmref(t->array, lj_mem_realloc(L, array,
oldasize*sizeof(TValue), asize*sizeof(TValue)));
}
if (oldhmask > 0) { /* Reinsert pairs from old hash part. */
global_State *g;
uint32_t i;
for (i = 0; i <= oldhmask; i++) {
Node *n = &oldnode[i];
if (!tvisnil(&n->val))
copyTV(L, lj_tab_set(L, t, &n->key), &n->val);
}
g = G(L);
lj_mem_freevec(g, oldnode, oldhmask+1, Node);
}
}
static uint32_t countint(cTValue *key, uint32_t *bins)
{
lua_assert(!tvisint(key));
if (tvisnum(key)) {
lua_Number nk = numV(key);
int32_t k = lj_num2int(nk);
if ((uint32_t)k < LJ_MAX_ASIZE && nk == (lua_Number)k) {
bins[(k > 2 ? lj_fls((uint32_t)(k-1)) : 0)]++;
return 1;
}
}
return 0;
}
static uint32_t countarray(const GCtab *t, uint32_t *bins)
{
uint32_t na, b, i;
if (t->asize == 0) return 0;
for (na = i = b = 0; b < LJ_MAX_ABITS; b++) {
uint32_t n, top = 2u << b;
TValue *array;
if (top >= t->asize) {
top = t->asize-1;
if (i > top)
break;
}
array = tvref(t->array);
for (n = 0; i <= top; i++)
if (!tvisnil(&array[i]))
n++;
bins[b] += n;
na += n;
}
return na;
}
static uint32_t counthash(const GCtab *t, uint32_t *bins, uint32_t *narray)
{
uint32_t total, na, i, hmask = t->hmask;
Node *node = noderef(t->node);
for (total = na = 0, i = 0; i <= hmask; i++) {
Node *n = &node[i];
if (!tvisnil(&n->val)) {
na += countint(&n->key, bins);
total++;
}
}
*narray += na;
return total;
}
static uint32_t bestasize(uint32_t bins[], uint32_t *narray)
{
uint32_t b, sum, na = 0, sz = 0, nn = *narray;
for (b = 0, sum = 0; 2*nn > (1u<<b) && sum != nn; b++)
if (bins[b] > 0 && 2*(sum += bins[b]) > (1u<<b)) {
sz = (2u<<b)+1;
na = sum;
}
*narray = sz;
return na;
}
static void rehashtab(lua_State *L, GCtab *t, cTValue *ek)
{
uint32_t bins[LJ_MAX_ABITS];
uint32_t total, asize, na, i;
for (i = 0; i < LJ_MAX_ABITS; i++) bins[i] = 0;
asize = countarray(t, bins);
total = 1 + asize;
total += counthash(t, bins, &asize);
asize += countint(ek, bins);
na = bestasize(bins, &asize);
total -= na;
resizetab(L, t, asize, hsize2hbits(total));
}
#if LJ_HASFFI
void lj_tab_rehash(lua_State *L, GCtab *t)
{
rehashtab(L, t, niltv(L));
}
#endif
void lj_tab_reasize(lua_State *L, GCtab *t, uint32_t nasize)
{
resizetab(L, t, nasize+1, t->hmask > 0 ? lj_fls(t->hmask)+1 : 0);
}
/* -- Table getters ------------------------------------------------------- */
cTValue * LJ_FASTCALL lj_tab_getinth(GCtab *t, int32_t key)
{
TValue k;
Node *n;
k.n = (lua_Number)key;
n = hashnum(t, &k);
do {
if (tvisnum(&n->key) && n->key.n == k.n)
return &n->val;
} while ((n = nextnode(n)));
return NULL;
}
cTValue *lj_tab_getstr(GCtab *t, GCstr *key)
{
Node *n = hashstr(t, key);
do {
if (tvisstr(&n->key) && strV(&n->key) == key)
return &n->val;
} while ((n = nextnode(n)));
return NULL;
}
cTValue *lj_tab_get(lua_State *L, GCtab *t, cTValue *key)
{
if (tvisstr(key)) {
cTValue *tv = lj_tab_getstr(t, strV(key));
if (tv)
return tv;
} else if (tvisint(key)) {
cTValue *tv = lj_tab_getint(t, intV(key));
if (tv)
return tv;
} else if (tvisnum(key)) {
lua_Number nk = numV(key);
int32_t k = lj_num2int(nk);
if (nk == (lua_Number)k) {
cTValue *tv = lj_tab_getint(t, k);
if (tv)
return tv;
} else {
goto genlookup; /* Else use the generic lookup. */
}
} else if (!tvisnil(key)) {
Node *n;
genlookup:
n = hashkey(t, key);
do {
if (lj_obj_equal(&n->key, key))
return &n->val;
} while ((n = nextnode(n)));
}
return niltv(L);
}
/* -- Table setters ------------------------------------------------------- */
/* Insert new key. Use Brent's variation to optimize the chain length. */
TValue *lj_tab_newkey(lua_State *L, GCtab *t, cTValue *key)
{
Node *n = hashkey(t, key);
if (!tvisnil(&n->val) || t->hmask == 0) {
Node *nodebase = noderef(t->node);
Node *collide, *freenode = noderef(nodebase->freetop);
lua_assert(freenode >= nodebase && freenode <= nodebase+t->hmask+1);
do {
if (freenode == nodebase) { /* No free node found? */
rehashtab(L, t, key); /* Rehash table. */
return lj_tab_set(L, t, key); /* Retry key insertion. */
}
} while (!tvisnil(&(--freenode)->key));
setmref(nodebase->freetop, freenode);
lua_assert(freenode != &G(L)->nilnode);
collide = hashkey(t, &n->key);
if (collide != n) { /* Colliding node not the main node? */
while (noderef(collide->next) != n) /* Find predecessor. */
collide = nextnode(collide);
setmref(collide->next, freenode); /* Relink chain. */
/* Copy colliding node into free node and free main node. */
freenode->val = n->val;
freenode->key = n->key;
freenode->next = n->next;
setmref(n->next, NULL);
setnilV(&n->val);
/* Rechain pseudo-resurrected string keys with colliding hashes. */
while (nextnode(freenode)) {
Node *nn = nextnode(freenode);
if (tvisstr(&nn->key) && !tvisnil(&nn->val) &&
hashstr(t, strV(&nn->key)) == n) {
freenode->next = nn->next;
nn->next = n->next;
setmref(n->next, nn);
} else {
freenode = nn;
}
}
} else { /* Otherwise use free node. */
setmrefr(freenode->next, n->next); /* Insert into chain. */
setmref(n->next, freenode);
n = freenode;
}
}
n->key.u64 = key->u64;
if (LJ_UNLIKELY(tvismzero(&n->key)))
n->key.u64 = 0;
lj_gc_anybarriert(L, t);
lua_assert(tvisnil(&n->val));
return &n->val;
}
TValue *lj_tab_setinth(lua_State *L, GCtab *t, int32_t key)
{
TValue k;
Node *n;
k.n = (lua_Number)key;
n = hashnum(t, &k);
do {
if (tvisnum(&n->key) && n->key.n == k.n)
return &n->val;
} while ((n = nextnode(n)));
return lj_tab_newkey(L, t, &k);
}
TValue *lj_tab_setstr(lua_State *L, GCtab *t, GCstr *key)
{
TValue k;
Node *n = hashstr(t, key);
do {
if (tvisstr(&n->key) && strV(&n->key) == key)
return &n->val;
} while ((n = nextnode(n)));
setstrV(L, &k, key);
return lj_tab_newkey(L, t, &k);
}
TValue *lj_tab_set(lua_State *L, GCtab *t, cTValue *key)
{
Node *n;
t->nomm = 0; /* Invalidate negative metamethod cache. */
if (tvisstr(key)) {
return lj_tab_setstr(L, t, strV(key));
} else if (tvisint(key)) {
return lj_tab_setint(L, t, intV(key));
} else if (tvisnum(key)) {
lua_Number nk = numV(key);
int32_t k = lj_num2int(nk);
if (nk == (lua_Number)k)
return lj_tab_setint(L, t, k);
if (tvisnan(key))
lj_err_msg(L, LJ_ERR_NANIDX);
/* Else use the generic lookup. */
} else if (tvisnil(key)) {
lj_err_msg(L, LJ_ERR_NILIDX);
}
n = hashkey(t, key);
do {
if (lj_obj_equal(&n->key, key))
return &n->val;
} while ((n = nextnode(n)));
return lj_tab_newkey(L, t, key);
}
/* -- Table traversal ----------------------------------------------------- */
/* Get the traversal index of a key. */
static uint32_t keyindex(lua_State *L, GCtab *t, cTValue *key)
{
TValue tmp;
if (tvisint(key)) {
int32_t k = intV(key);
if ((uint32_t)k < t->asize)
return (uint32_t)k; /* Array key indexes: [0..t->asize-1] */
setnumV(&tmp, (lua_Number)k);
key = &tmp;
} else if (tvisnum(key)) {
lua_Number nk = numV(key);
int32_t k = lj_num2int(nk);
if ((uint32_t)k < t->asize && nk == (lua_Number)k)
return (uint32_t)k; /* Array key indexes: [0..t->asize-1] */
}
if (!tvisnil(key)) {
Node *n = hashkey(t, key);
do {
if (lj_obj_equal(&n->key, key))
return t->asize + (uint32_t)(n - noderef(t->node));
/* Hash key indexes: [t->asize..t->asize+t->nmask] */
} while ((n = nextnode(n)));
if (key->u32.hi == 0xfffe7fff) /* ITERN was despecialized while running. */
return key->u32.lo - 1;
lj_err_msg(L, LJ_ERR_NEXTIDX);
return 0; /* unreachable */
}
return ~0u; /* A nil key starts the traversal. */
}
/* Advance to the next step in a table traversal. */
int lj_tab_next(lua_State *L, GCtab *t, TValue *key)
{
uint32_t i = keyindex(L, t, key); /* Find predecessor key index. */
for (i++; i < t->asize; i++) /* First traverse the array keys. */
if (!tvisnil(arrayslot(t, i))) {
setintV(key, i);
copyTV(L, key+1, arrayslot(t, i));
return 1;
}
for (i -= t->asize; i <= t->hmask; i++) { /* Then traverse the hash keys. */
Node *n = &noderef(t->node)[i];
if (!tvisnil(&n->val)) {
copyTV(L, key, &n->key);
copyTV(L, key+1, &n->val);
return 1;
}
}
return 0; /* End of traversal. */
}
/* -- Table length calculation -------------------------------------------- */
static MSize unbound_search(GCtab *t, MSize j)
{
cTValue *tv;
MSize i = j; /* i is zero or a present index */
j++;
/* find `i' and `j' such that i is present and j is not */
while ((tv = lj_tab_getint(t, (int32_t)j)) && !tvisnil(tv)) {
i = j;
j *= 2;
if (j > (MSize)(INT_MAX-2)) { /* overflow? */
/* table was built with bad purposes: resort to linear search */
i = 1;
while ((tv = lj_tab_getint(t, (int32_t)i)) && !tvisnil(tv)) i++;
return i - 1;
}
}
/* now do a binary search between them */
while (j - i > 1) {
MSize m = (i+j)/2;
cTValue *tvb = lj_tab_getint(t, (int32_t)m);
if (tvb && !tvisnil(tvb)) i = m; else j = 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).
*/
MSize LJ_FASTCALL lj_tab_len(GCtab *t)
{
MSize j = (MSize)t->asize;
if (j > 1 && tvisnil(arrayslot(t, j-1))) {
MSize i = 1;
while (j - i > 1) {
MSize m = (i+j)/2;
if (tvisnil(arrayslot(t, m-1))) j = m; else i = m;
}
return i-1;
}
if (j) j--;
if (t->hmask <= 0)
return j;
return unbound_search(t, j);
}
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