/*
** $Id: lstring.c,v 2.8.1.1 2007年12月27日 13:02:25 roberto Exp $
** String table (keeps all strings handled by Lua)
** See Copyright Notice in lua.h
*/


#include <string.h>

#define lstring_c
#define LUA_CORE

#include "lua.h"

#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "lstring.h"



void luaS_resize (lua_State *L, int newsize) {
 GCObject **newhash;
 stringtable *tb;
 int i;
 if (G(L)->gcstate == GCSsweepstring)
 return; /* cannot resize during GC traverse */
 newhash = luaM_newvector(L, newsize, GCObject *);
 tb = &G(L)->strt;
 for (i=0; i<newsize; i++) newhash[i] = NULL;
 /* rehash */
 for (i=0; i<tb->size; i++) {
 GCObject *p = tb->hash[i];
 while (p) { /* for each node in the list */
 GCObject *next = p->gch.next; /* save next */
 unsigned int h = gco2ts(p)->hash;
 int h1 = lmod(h, newsize); /* new position */
 lua_assert(cast_int(h%newsize) == lmod(h, newsize));
 p->gch.next = newhash[h1]; /* chain it */
 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,
 unsigned int h) {
 TString *ts;
 stringtable *tb;
 if (l+1 > (MAX_SIZET - sizeof(TString))/sizeof(char))
 luaM_toobig(L);
 ts = cast(TString *, luaM_malloc(L, (l+1)*sizeof(char)+sizeof(TString)));
 ts->tsv.len = l;
 ts->tsv.hash = h;
 ts->tsv.marked = luaC_white(G(L));
 ts->tsv.tt = LUA_TSTRING;
 ts->tsv.reserved = 0;
 memcpy(ts+1, str, l*sizeof(char));
 ((char *)(ts+1))[l] = '0円'; /* ending 0 */
 tb = &G(L)->strt;
 h = lmod(h, tb->size);
 ts->tsv.next = tb->hash[h]; /* chain new entry */
 tb->hash[h] = obj2gco(ts);
 tb->nuse++;
 if (tb->nuse > cast(lu_int32, 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) {
 GCObject *o;
 unsigned int h = cast(unsigned int, 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)+cast(unsigned char, str[l1-1]));
 for (o = G(L)->strt.hash[lmod(h, G(L)->strt.size)];
 o != NULL;
 o = o->gch.next) {
 TString *ts = rawgco2ts(o);
 if (ts->tsv.len == l && (memcmp(str, getstr(ts), l) == 0)) {
 /* string may be dead */
 if (isdead(G(L), o)) changewhite(o);
 return ts;
 }
 }
 return newlstr(L, str, l, h); /* not found */
}


Udata *luaS_newudata (lua_State *L, size_t s, Table *e) {
 Udata *u;
 if (s > MAX_SIZET - sizeof(Udata))
 luaM_toobig(L);
 u = cast(Udata *, luaM_malloc(L, s + sizeof(Udata)));
 u->uv.marked = luaC_white(G(L)); /* is not finalized */
 u->uv.tt = LUA_TUSERDATA;
 u->uv.len = s;
 u->uv.metatable = NULL;
 u->uv.env = e;
 /* chain it on udata list (after main thread) */
 u->uv.next = G(L)->mainthread->next;
 G(L)->mainthread->next = obj2gco(u);
 return u;
}