Line data    Source code

       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          425 : void luaS_resize (lua_State *L, int newsize) {
      23              :   GCObject **newhash;
      24              :   stringtable *tb;
      25              :   int i;
      26          425 :   if (G(L)->gcstate == GCSsweepstring)
      27            0 :     return;  /* cannot resize during GC traverse */
      28          425 :   newhash = luaM_newvector(L, newsize, GCObject *);
      29          425 :   tb = &G(L)->strt;
      30        91593 :   for (i=0; i<newsize; i++) newhash[i] = NULL;
      31              :   /* rehash */
      32        44489 :   for (i=0; i<tb->size; i++) {
      33        44064 :     GCObject *p = tb->hash[i];
      34        88458 :     while (p) {  /* for each node in the list */
      35        44394 :       GCObject *next = p->gch.next;  /* save next */
      36        44394 :       unsigned int h = gco2ts(p)->hash;
      37        44394 :       int h1 = lmod(h, newsize);  /* new position */
      38              :       lua_assert(cast_int(h%newsize) == lmod(h, newsize));
      39        44394 :       p->gch.next = newhash[h1];  /* chain it */
      40        44394 :       newhash[h1] = p;
      41        44394 :       p = next;
      42              :     }
      43              :   }
      44          425 :   luaM_freearray(L, tb->hash, tb->size, TString *);
      45          425 :   tb->size = newsize;
      46          425 :   tb->hash = newhash;
      47              : }
      48              : 
      49              : 
      50        42440 : static TString *newlstr (lua_State *L, const char *str, size_t l,
      51              :                                        unsigned int h) {
      52              :   TString *ts;
      53              :   stringtable *tb;
      54        42440 :   if (l+1 > (MAX_SIZET - sizeof(TString))/sizeof(char))
      55            0 :     luaM_toobig(L);
      56        42440 :   ts = cast(TString *, luaM_malloc(L, (l+1)*sizeof(char)+sizeof(TString)));
      57        42440 :   ts->tsv.len = l;
      58        42440 :   ts->tsv.hash = h;
      59        42440 :   ts->tsv.marked = luaC_white(G(L));
      60        42440 :   ts->tsv.tt = LUA_TSTRING;
      61        42440 :   ts->tsv.reserved = 0;
      62        42440 :   memcpy(ts+1, str, l*sizeof(char));
      63        42440 :   ((char *)(ts+1))[l] = '\0';  /* ending 0 */
      64        42440 :   tb = &G(L)->strt;
      65        42440 :   h = lmod(h, tb->size);
      66        42440 :   ts->tsv.next = tb->hash[h];  /* chain new entry */
      67        42440 :   tb->hash[h] = obj2gco(ts);
      68        42440 :   tb->nuse++;
      69        42440 :   if (tb->nuse > cast(lu_int32, tb->size) && tb->size <= MAX_INT/2)
      70          330 :     luaS_resize(L, tb->size*2);  /* too crowded */
      71        42440 :   return ts;
      72              : }
      73              : 
      74              : 
      75       131017 : TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
      76              :   GCObject *o;
      77       131017 :   unsigned int h = cast(unsigned int, l);  /* seed */
      78       131017 :   size_t step = (l>>5)+1;  /* if string is too long, don't hash all its chars */
      79              :   size_t l1;
      80      1053012 :   for (l1=l; l1>=step; l1-=step)  /* compute hash */
      81       921995 :     h = h ^ ((h<<5)+(h>>2)+cast(unsigned char, str[l1-1]));
      82       131017 :   for (o = G(L)->strt.hash[lmod(h, G(L)->strt.size)];
      83       180129 :        o != NULL;
      84        49112 :        o = o->gch.next) {
      85       137689 :     TString *ts = rawgco2ts(o);
      86       137689 :     if (ts->tsv.len == l && (memcmp(str, getstr(ts), l) == 0)) {
      87              :       /* string may be dead */
      88        88577 :       if (isdead(G(L), o)) changewhite(o);
      89        88577 :       return ts;
      90              :     }
      91              :   }
      92        42440 :   return newlstr(L, str, l, h);  /* not found */
      93              : }
      94              : 
      95              : 
      96          364 : Udata *luaS_newudata (lua_State *L, size_t s, Table *e) {
      97              :   Udata *u;
      98          364 :   if (s > MAX_SIZET - sizeof(Udata))
      99            0 :     luaM_toobig(L);
     100          364 :   u = cast(Udata *, luaM_malloc(L, s + sizeof(Udata)));
     101          364 :   u->uv.marked = luaC_white(G(L));  /* is not finalized */
     102          364 :   u->uv.tt = LUA_TUSERDATA;
     103          364 :   u->uv.len = s;
     104          364 :   u->uv.metatable = NULL;
     105          364 :   u->uv.env = e;
     106              :   /* chain it on udata list (after main thread) */
     107          364 :   u->uv.next = G(L)->mainthread->next;
     108          364 :   G(L)->mainthread->next = obj2gco(u);
     109          364 :   return u;
     110              : }
     111              :