/*

** $Id: lstring.c,v 2.8.1.1 2007/12/27 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';  /* 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;

}