rpm  4.5
lstring.c
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1 /*
2 ** $Id: lstring.c,v 1.1 2004/03/16 21:58:30 niemeyer 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 
12 #include "lua.h"
13 
14 #include "lmem.h"
15 #include "lobject.h"
16 #include "lstate.h"
17 #include "lstring.h"
18 
19 
20 
22  lua_assert(G(L)->strt.nuse==0);
23  luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size, TString *);
24 }
25 
26 
27 void luaS_resize (lua_State *L, int newsize) {
28  GCObject **newhash = luaM_newvector(L, newsize, GCObject *);
29  stringtable *tb = &G(L)->strt;
30  int i;
31  for (i=0; i<newsize; i++) newhash[i] = NULL;
32  /* rehash */
33  for (i=0; i<tb->size; i++) {
34  GCObject *p = tb->hash[i];
35  while (p) { /* for each node in the list */
36  GCObject *next = p->gch.next; /* save next */
37  lu_hash h = gcotots(p)->tsv.hash;
38  int h1 = lmod(h, newsize); /* new position */
39  lua_assert(cast(int, h%newsize) == lmod(h, newsize));
40  p->gch.next = newhash[h1]; /* chain it */
41  newhash[h1] = p;
42  p = next;
43  }
44  }
45  luaM_freearray(L, tb->hash, tb->size, TString *);
46  tb->size = newsize;
47  tb->hash = newhash;
48 }
49 
50 
51 /*@null@*/
52 static TString *newlstr (lua_State *L, const char *str, size_t l, lu_hash h)
53  /*@modifies L @*/
54 {
55  TString *ts = cast(TString *, luaM_malloc(L, sizestring(l)));
56  stringtable *tb;
57  ts->tsv.len = l;
58  ts->tsv.hash = h;
59  ts->tsv.marked = 0;
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] = valtogco(ts);
68  tb->nuse++;
69  if (tb->nuse > cast(ls_nstr, tb->size) && tb->size <= MAX_INT/2)
70  luaS_resize(L, tb->size*2); /* too crowded */
71  return ts;
72 }
73 
74 
75 TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
76  GCObject *o;
77  lu_hash h = (lu_hash)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)+(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 = gcotots(o);
86  if (ts->tsv.len == l && (memcmp(str, getstr(ts), l) == 0))
87  return ts;
88  }
89  return newlstr(L, str, l, h); /* not found */
90 }
91 
92 
93 Udata *luaS_newudata (lua_State *L, size_t s) {
94  Udata *u;
95  u = cast(Udata *, luaM_malloc(L, sizeudata(s)));
96  u->uv.marked = (1<<1); /* is not finalized */
97  u->uv.tt = LUA_TUSERDATA;
98  u->uv.len = s;
99  u->uv.metatable = hvalue(defaultmeta(L));
100  /* chain it on udata list */
101  u->uv.next = G(L)->rootudata;
102  G(L)->rootudata = valtogco(u);
103  return u;
104 }
105