| 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 | |
| 22 | void 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 | |
| 50 | static 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 | |
| 75 | TString *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 | |
| 96 | Udata *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 | |