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/script_binding/lua/lua/lstring.c

http://ftk.googlecode.com/
C | 111 lines | 88 code | 15 blank | 8 comment | 18 complexity | 0ffb701fcc7fc6aeae1d2779b47a1694 MD5 | raw file
  1/*
  2** $Id: lstring.c,v 2.8.1.1 2007/12/27 13:02:25 roberto Exp $
  3** String table (keeps all strings handled by Lua)
  4** See Copyright Notice in lua.h
  5*/
  6
  7
  8#include <string.h>
  9
 10#define lstring_c
 11#define LUA_CORE
 12
 13#include "lua.h"
 14
 15#include "lmem.h"
 16#include "lobject.h"
 17#include "lstate.h"
 18#include "lstring.h"
 19
 20
 21
 22void luaS_resize (lua_State *L, int newsize) {
 23  GCObject **newhash;
 24  stringtable *tb;
 25  int i;
 26  if (G(L)->gcstate == GCSsweepstring)
 27    return;  /* cannot resize during GC traverse */
 28  newhash = luaM_newvector(L, newsize, GCObject *);
 29  tb = &G(L)->strt;
 30  for (i=0; i<newsize; i++) newhash[i] = NULL;
 31  /* rehash */
 32  for (i=0; i<tb->size; i++) {
 33    GCObject *p = tb->hash[i];
 34    while (p) {  /* for each node in the list */
 35      GCObject *next = p->gch.next;  /* save next */
 36      unsigned int h = gco2ts(p)->hash;
 37      int h1 = lmod(h, newsize);  /* new position */
 38      lua_assert(cast_int(h%newsize) == lmod(h, newsize));
 39      p->gch.next = newhash[h1];  /* chain it */
 40      newhash[h1] = p;
 41      p = next;
 42    }
 43  }
 44  luaM_freearray(L, tb->hash, tb->size, TString *);
 45  tb->size = newsize;
 46  tb->hash = newhash;
 47}
 48
 49
 50static TString *newlstr (lua_State *L, const char *str, size_t l,
 51                                       unsigned int h) {
 52  TString *ts;
 53  stringtable *tb;
 54  if (l+1 > (MAX_SIZET - sizeof(TString))/sizeof(char))
 55    luaM_toobig(L);
 56  ts = cast(TString *, luaM_malloc(L, (l+1)*sizeof(char)+sizeof(TString)));
 57  ts->tsv.len = l;
 58  ts->tsv.hash = h;
 59  ts->tsv.marked = luaC_white(G(L));
 60  ts->tsv.tt = LUA_TSTRING;
 61  ts->tsv.reserved = 0;
 62  memcpy(ts+1, str, l*sizeof(char));
 63  ((char *)(ts+1))[l] = '\0';  /* ending 0 */
 64  tb = &G(L)->strt;
 65  h = lmod(h, tb->size);
 66  ts->tsv.next = tb->hash[h];  /* chain new entry */
 67  tb->hash[h] = obj2gco(ts);
 68  tb->nuse++;
 69  if (tb->nuse > cast(lu_int32, tb->size) && tb->size <= MAX_INT/2)
 70    luaS_resize(L, tb->size*2);  /* too crowded */
 71  return ts;
 72}
 73
 74
 75TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
 76  GCObject *o;
 77  unsigned int h = cast(unsigned int, l);  /* seed */
 78  size_t step = (l>>5)+1;  /* if string is too long, don't hash all its chars */
 79  size_t l1;
 80  for (l1=l; l1>=step; l1-=step)  /* compute hash */
 81    h = h ^ ((h<<5)+(h>>2)+cast(unsigned char, str[l1-1]));
 82  for (o = G(L)->strt.hash[lmod(h, G(L)->strt.size)];
 83       o != NULL;
 84       o = o->gch.next) {
 85    TString *ts = rawgco2ts(o);
 86    if (ts->tsv.len == l && (memcmp(str, getstr(ts), l) == 0)) {
 87      /* string may be dead */
 88      if (isdead(G(L), o)) changewhite(o);
 89      return ts;
 90    }
 91  }
 92  return newlstr(L, str, l, h);  /* not found */
 93}
 94
 95
 96Udata *luaS_newudata (lua_State *L, size_t s, Table *e) {
 97  Udata *u;
 98  if (s > MAX_SIZET - sizeof(Udata))
 99    luaM_toobig(L);
100  u = cast(Udata *, luaM_malloc(L, s + sizeof(Udata)));
101  u->uv.marked = luaC_white(G(L));  /* is not finalized */
102  u->uv.tt = LUA_TUSERDATA;
103  u->uv.len = s;
104  u->uv.metatable = NULL;
105  u->uv.env = e;
106  /* chain it on udata list (after main thread) */
107  u->uv.next = G(L)->mainthread->next;
108  G(L)->mainthread->next = obj2gco(u);
109  return u;
110}
111