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/*
** $Id: lstring.c,v 1.51 2001/01/19 13:20:30 roberto Exp roberto $
** String table (keeps all strings handled by Lua)
** See Copyright Notice in lua.h
*/
#include <string.h>
#include "lua.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "lstring.h"
void luaS_init (lua_State *L) {
luaS_resize(L, &G(L)->strt, MINPOWER2);
luaS_resize(L, &G(L)->udt, MINPOWER2);
}
void luaS_freeall (lua_State *L) {
lua_assert(G(L)->strt.nuse==0);
luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size, TString *);
lua_assert(G(L)->udt.nuse==0);
luaM_freearray(L, G(L)->udt.hash, G(L)->udt.size, TString *);
}
void luaS_resize (lua_State *L, stringtable *tb, int newsize) {
TString **newhash = luaM_newvector(L, newsize, TString *);
int i;
for (i=0; i<newsize; i++) newhash[i] = NULL;
/* rehash */
for (i=0; i<tb->size; i++) {
TString *p = tb->hash[i];
while (p) { /* for each node in the list */
TString *next = p->nexthash; /* save next */
luint32 h = (tb == &G(L)->strt) ? p->u.s.hash : IntPoint(p->u.d.value);
int h1 = lmod(h, newsize); /* new position */
lua_assert((int)(h%newsize) == lmod(h, newsize));
p->nexthash = newhash[h1]; /* chain it in new position */
newhash[h1] = p;
p = next;
}
}
luaM_freearray(L, tb->hash, tb->size, TString *);
tb->size = newsize;
tb->hash = newhash;
}
static void newentry (lua_State *L, stringtable *tb, TString *ts, int h) {
ts->nexthash = tb->hash[h]; /* chain new entry */
tb->hash[h] = ts;
tb->nuse++;
if (tb->nuse > (luint32)tb->size && tb->size < MAX_INT/2) /* too crowded? */
luaS_resize(L, tb, tb->size*2);
}
TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
TString *ts;
luint32 h = l; /* seed */
size_t step = (l>>5)+1; /* if string is too long, don't hash all its chars */
size_t l1;
for (l1=l; l1>=step; l1-=step) /* compute hash */
h = h ^ ((h<<5)+(h>>2)+(unsigned char)str[l1-1]);
for (ts = G(L)->strt.hash[lmod(h, G(L)->strt.size)]; ts; ts = ts->nexthash) {
if (ts->len == l && (memcmp(str, ts->str, l) == 0))
return ts;
}
/* not found */
ts = (TString *)luaM_malloc(L, sizestring(l));
ts->marked = 0;
ts->nexthash = NULL;
ts->len = l;
ts->u.s.hash = h;
ts->u.s.constindex = 0;
memcpy(ts->str, str, l);
ts->str[l] = 0; /* ending 0 */
newentry(L, &G(L)->strt, ts, lmod(h, G(L)->strt.size)); /* insert it */
return ts;
}
TString *luaS_newudata (lua_State *L, size_t s, void *udata) {
union L_UTString *uts = (union L_UTString *)luaM_malloc(L, sizeudata(s));
TString *ts = &uts->ts;
ts->marked = 0;
ts->nexthash = NULL;
ts->len = s;
ts->u.d.tag = 0;
ts->u.d.value = (udata == NULL) ? uts+1 : udata;
/* insert it on table */
newentry(L, &G(L)->udt, ts, lmod(IntPoint(ts->u.d.value), G(L)->udt.size));
return ts;
}
TString *luaS_createudata (lua_State *L, void *udata, int tag) {
int h1 = lmod(IntPoint(udata), G(L)->udt.size);
TString *ts;
for (ts = G(L)->udt.hash[h1]; ts; ts = ts->nexthash) {
if (udata == ts->u.d.value && (tag == ts->u.d.tag || tag == LUA_ANYTAG))
return ts;
}
/* not found */
ts = luaS_newudata(L, 0, udata);
if (tag != LUA_ANYTAG)
ts->u.d.tag = tag;
return ts;
}
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