1*572c4311Sfengbojiang /*
2*572c4311Sfengbojiang ** $Id: lstring.c,v 2.8.1.1 2007/12/27 13:02:25 roberto Exp $
3*572c4311Sfengbojiang ** String table (keeps all strings handled by Lua)
4*572c4311Sfengbojiang ** See Copyright Notice in lua.h
5*572c4311Sfengbojiang */
6*572c4311Sfengbojiang
7*572c4311Sfengbojiang
8*572c4311Sfengbojiang #include <string.h>
9*572c4311Sfengbojiang
10*572c4311Sfengbojiang #define lstring_c
11*572c4311Sfengbojiang #define LUA_CORE
12*572c4311Sfengbojiang
13*572c4311Sfengbojiang #include "lua.h"
14*572c4311Sfengbojiang
15*572c4311Sfengbojiang #include "lmem.h"
16*572c4311Sfengbojiang #include "lobject.h"
17*572c4311Sfengbojiang #include "lstate.h"
18*572c4311Sfengbojiang #include "lstring.h"
19*572c4311Sfengbojiang
20*572c4311Sfengbojiang
21*572c4311Sfengbojiang
luaS_resize(lua_State * L,int newsize)22*572c4311Sfengbojiang void luaS_resize (lua_State *L, int newsize) {
23*572c4311Sfengbojiang GCObject **newhash;
24*572c4311Sfengbojiang stringtable *tb;
25*572c4311Sfengbojiang int i;
26*572c4311Sfengbojiang if (G(L)->gcstate == GCSsweepstring)
27*572c4311Sfengbojiang return; /* cannot resize during GC traverse */
28*572c4311Sfengbojiang newhash = luaM_newvector(L, newsize, GCObject *);
29*572c4311Sfengbojiang tb = &G(L)->strt;
30*572c4311Sfengbojiang for (i=0; i<newsize; i++) newhash[i] = NULL;
31*572c4311Sfengbojiang /* rehash */
32*572c4311Sfengbojiang for (i=0; i<tb->size; i++) {
33*572c4311Sfengbojiang GCObject *p = tb->hash[i];
34*572c4311Sfengbojiang while (p) { /* for each node in the list */
35*572c4311Sfengbojiang GCObject *next = p->gch.next; /* save next */
36*572c4311Sfengbojiang unsigned int h = gco2ts(p)->hash;
37*572c4311Sfengbojiang int h1 = lmod(h, newsize); /* new position */
38*572c4311Sfengbojiang lua_assert(cast_int(h%newsize) == lmod(h, newsize));
39*572c4311Sfengbojiang p->gch.next = newhash[h1]; /* chain it */
40*572c4311Sfengbojiang newhash[h1] = p;
41*572c4311Sfengbojiang p = next;
42*572c4311Sfengbojiang }
43*572c4311Sfengbojiang }
44*572c4311Sfengbojiang luaM_freearray(L, tb->hash, tb->size, TString *);
45*572c4311Sfengbojiang tb->size = newsize;
46*572c4311Sfengbojiang tb->hash = newhash;
47*572c4311Sfengbojiang }
48*572c4311Sfengbojiang
49*572c4311Sfengbojiang
newlstr(lua_State * L,const char * str,size_t l,unsigned int h)50*572c4311Sfengbojiang static TString *newlstr (lua_State *L, const char *str, size_t l,
51*572c4311Sfengbojiang unsigned int h) {
52*572c4311Sfengbojiang TString *ts;
53*572c4311Sfengbojiang stringtable *tb;
54*572c4311Sfengbojiang if (l+1 > (MAX_SIZET - sizeof(TString))/sizeof(char))
55*572c4311Sfengbojiang luaM_toobig(L);
56*572c4311Sfengbojiang ts = cast(TString *, luaM_malloc(L, (l+1)*sizeof(char)+sizeof(TString)));
57*572c4311Sfengbojiang ts->tsv.len = l;
58*572c4311Sfengbojiang ts->tsv.hash = h;
59*572c4311Sfengbojiang ts->tsv.marked = luaC_white(G(L));
60*572c4311Sfengbojiang ts->tsv.tt = LUA_TSTRING;
61*572c4311Sfengbojiang ts->tsv.reserved = 0;
62*572c4311Sfengbojiang memcpy(ts+1, str, l*sizeof(char));
63*572c4311Sfengbojiang ((char *)(ts+1))[l] = '\0'; /* ending 0 */
64*572c4311Sfengbojiang tb = &G(L)->strt;
65*572c4311Sfengbojiang h = lmod(h, tb->size);
66*572c4311Sfengbojiang ts->tsv.next = tb->hash[h]; /* chain new entry */
67*572c4311Sfengbojiang tb->hash[h] = obj2gco(ts);
68*572c4311Sfengbojiang tb->nuse++;
69*572c4311Sfengbojiang if (tb->nuse > cast(lu_int32, tb->size) && tb->size <= MAX_INT/2)
70*572c4311Sfengbojiang luaS_resize(L, tb->size*2); /* too crowded */
71*572c4311Sfengbojiang return ts;
72*572c4311Sfengbojiang }
73*572c4311Sfengbojiang
74*572c4311Sfengbojiang
luaS_newlstr(lua_State * L,const char * str,size_t l)75*572c4311Sfengbojiang TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
76*572c4311Sfengbojiang GCObject *o;
77*572c4311Sfengbojiang unsigned int h = cast(unsigned int, l); /* seed */
78*572c4311Sfengbojiang size_t step = (l>>5)+1; /* if string is too long, don't hash all its chars */
79*572c4311Sfengbojiang size_t l1;
80*572c4311Sfengbojiang for (l1=l; l1>=step; l1-=step) /* compute hash */
81*572c4311Sfengbojiang h = h ^ ((h<<5)+(h>>2)+cast(unsigned char, str[l1-1]));
82*572c4311Sfengbojiang for (o = G(L)->strt.hash[lmod(h, G(L)->strt.size)];
83*572c4311Sfengbojiang o != NULL;
84*572c4311Sfengbojiang o = o->gch.next) {
85*572c4311Sfengbojiang TString *ts = rawgco2ts(o);
86*572c4311Sfengbojiang if (ts->tsv.len == l && (memcmp(str, getstr(ts), l) == 0)) {
87*572c4311Sfengbojiang /* string may be dead */
88*572c4311Sfengbojiang if (isdead(G(L), o)) changewhite(o);
89*572c4311Sfengbojiang return ts;
90*572c4311Sfengbojiang }
91*572c4311Sfengbojiang }
92*572c4311Sfengbojiang return newlstr(L, str, l, h); /* not found */
93*572c4311Sfengbojiang }
94*572c4311Sfengbojiang
95*572c4311Sfengbojiang
luaS_newudata(lua_State * L,size_t s,Table * e)96*572c4311Sfengbojiang Udata *luaS_newudata (lua_State *L, size_t s, Table *e) {
97*572c4311Sfengbojiang Udata *u;
98*572c4311Sfengbojiang if (s > MAX_SIZET - sizeof(Udata))
99*572c4311Sfengbojiang luaM_toobig(L);
100*572c4311Sfengbojiang u = cast(Udata *, luaM_malloc(L, s + sizeof(Udata)));
101*572c4311Sfengbojiang u->uv.marked = luaC_white(G(L)); /* is not finalized */
102*572c4311Sfengbojiang u->uv.tt = LUA_TUSERDATA;
103*572c4311Sfengbojiang u->uv.len = s;
104*572c4311Sfengbojiang u->uv.metatable = NULL;
105*572c4311Sfengbojiang u->uv.env = e;
106*572c4311Sfengbojiang /* chain it on udata list (after main thread) */
107*572c4311Sfengbojiang u->uv.next = G(L)->mainthread->next;
108*572c4311Sfengbojiang G(L)->mainthread->next = obj2gco(u);
109*572c4311Sfengbojiang return u;
110*572c4311Sfengbojiang }
111*572c4311Sfengbojiang
112