/*

** $Id: lstring.c,v 1.78 2002/12/04 17:38:31 roberto Exp $

** String table (keeps all strings handled by Lua)

** See Copyright Notice in lua.h

*/





#include <string.h>



#define lstring_c



#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) {

  GCObject **newhash = luaM_newvector(L, newsize, GCObject *);

  stringtable *tb = &G(L)->strt;

  int i;

  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 */

      lu_hash h = gcotots(p)->tsv.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, lu_hash h) {

  TString *ts = cast(TString *, luaM_malloc(L, sizestring(l)));

  stringtable *tb;

  ts->tsv.len = l;

  ts->tsv.hash = h;

  ts->tsv.marked = 0;

  ts->tsv.tt = LUA_TSTRING;

  ts->tsv.reserved = 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.next = tb->hash[h];  /* chain new entry */

  tb->hash[h] = valtogco(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) {

  GCObject *o;

  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 (o = G(L)->strt.hash[lmod(h, G(L)->strt.size)];

       o != NULL;

       o = o->gch.next) {

    TString *ts = gcotots(o);

    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;

  u = cast(Udata *, luaM_malloc(L, sizeudata(s)));

  u->uv.marked = (1<<1);  /* is not finalized */

  u->uv.tt = LUA_TUSERDATA;

  u->uv.len = s;

  u->uv.metatable = hvalue(defaultmeta(L));

  /* chain it on udata list */

  u->uv.next = G(L)->rootudata;

  G(L)->rootudata = valtogco(u);

  return u;

}



