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source: code/trunk/src/lua/lstring.c @ 2187

Last change on this file since 2187 was 1810, checked in by rgrieder, 16 years ago

merged ceguilua branch back to trunk

  • Property svn:eol-style set to native
File size: 3.0 KB
Line 
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
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