lua/lstring.c

98 lines
2.6 KiB
C

/*
** $Id: lstring.c,v 1.73 2002/03/20 18:37:13 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_freeall (lua_State *L) {
lua_assert(G(L)->strt.nuse==0);
luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size, TString *);
}
void luaS_resize (lua_State *L, int newsize) {
TString **newhash = luaM_newvector(L, newsize, TString *);
stringtable *tb = &G(L)->strt;
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->tsv.nexthash; /* save next */
lu_hash h = p->tsv.hash;
int h1 = lmod(h, newsize); /* new position */
lua_assert(cast(int, h%newsize) == lmod(h, newsize));
p->tsv.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 TString *newlstr (lua_State *L, const char *str, size_t l, lu_hash h) {
TString *ts = cast(TString *, luaM_malloc(L, sizestring(l)));
stringtable *tb;
ts->tsv.nexthash = NULL;
ts->tsv.len = l;
ts->tsv.hash = h;
ts->tsv.marked = 0;
memcpy(ts+1, str, l*sizeof(char));
((char *)(ts+1))[l] = '\0'; /* ending 0 */
tb = &G(L)->strt;
h = lmod(h, tb->size);
ts->tsv.nexthash = tb->hash[h]; /* chain new entry */
tb->hash[h] = ts;
tb->nuse++;
if (tb->nuse > cast(ls_nstr, tb->size) && tb->size <= MAX_INT/2)
luaS_resize(L, tb->size*2); /* too crowded */
return ts;
}
TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
TString *ts;
lu_hash h = (lu_hash)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 != NULL;
ts = ts->tsv.nexthash) {
if (ts->tsv.len == l && (memcmp(str, getstr(ts), l) == 0))
return ts;
}
return newlstr(L, str, l, h); /* not found */
}
Udata *luaS_newudata (lua_State *L, size_t s) {
Udata *u;
s = (s+3) & (~(size_t)3); /* make sure size is multiple of 4 */
u = cast(Udata *, luaM_malloc(L, sizeudata(s)));
u->uv.len = s;
u->uv.metatable = hvalue(defaultmeta(L));
/* chain it on udata list */
u->uv.next = G(L)->rootudata;
G(L)->rootudata = u;
return u;
}