external/mit/lua/dist/src/lstring.c

   1 /*      $NetBSD: lstring.c,v 1.1.1.2 2012/03/15 00:08:08 alnsn Exp $    */
   2
   3 /*
   4 ** $Id: lstring.c,v 1.1.1.2 2012/03/15 00:08:08 alnsn Exp $
   5 ** String table (keeps all strings handled by Lua)
   6 ** See Copyright Notice in lua.h
   7 */
   8
   9
  10 #include <string.h>
  11
  12 #define lstring_c
  13 #define LUA_CORE
  14
  15 #include "lua.h"
  16
  17 #include "lmem.h"
  18 #include "lobject.h"
  19 #include "lstate.h"
  20 #include "lstring.h"
  21
  22
  23
  24 void luaS_resize (lua_State *L, int newsize) {
  25   GCObject **newhash;
  26   stringtable *tb;
  27   int i;
  28   if (G(L)->gcstate == GCSsweepstring)
  29     return;  /* cannot resize during GC traverse */
  30   newhash = luaM_newvector(L, newsize, GCObject *);
  31   tb = &G(L)->strt;
  32   for (i=0; i<newsize; i++) newhash[i] = NULL;
  33   /* rehash */
  34   for (i=0; i<tb->size; i++) {
  35     GCObject *p = tb->hash[i];
  36     while (p) {  /* for each node in the list */
  37       GCObject *next = p->gch.next;  /* save next */
  38       unsigned int h = gco2ts(p)->hash;
  39       int h1 = lmod(h, newsize);  /* new position */
  40       lua_assert(cast_int(h%newsize) == lmod(h, newsize));
  41       p->gch.next = newhash[h1];  /* chain it */
  42       newhash[h1] = p;
  43       p = next;
  44     }
  45   }
  46   luaM_freearray(L, tb->hash, tb->size, TString *);
  47   tb->size = newsize;
  48   tb->hash = newhash;
  49 }
  50
  51
  52 static TString *newlstr (lua_State *L, const char *str, size_t l,
  53                                        unsigned int h) {
  54   TString *ts;
  55   stringtable *tb;
  56   if (l+1 > (MAX_SIZET - sizeof(TString))/sizeof(char))
  57     luaM_toobig(L);
  58   ts = cast(TString *, luaM_malloc(L, (l+1)*sizeof(char)+sizeof(TString)));
  59   ts->tsv.len = l;
  60   ts->tsv.hash = h;
  61   ts->tsv.marked = luaC_white(G(L));
  62   ts->tsv.tt = LUA_TSTRING;
  63   ts->tsv.reserved = 0;
  64   memcpy(ts+1, str, l*sizeof(char));
  65   ((char *)(ts+1))[l] = '\0';  /* ending 0 */
  66   tb = &G(L)->strt;
  67   h = lmod(h, tb->size);
  68   ts->tsv.next = tb->hash[h];  /* chain new entry */
  69   tb->hash[h] = obj2gco(ts);
  70   tb->nuse++;
  71   if (tb->nuse > cast(lu_int32, tb->size) && tb->size <= MAX_INT/2)
  72     luaS_resize(L, tb->size*2);  /* too crowded */
  73   return ts;
  74 }
  75
  76
  77 TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
  78   GCObject *o;
  79   unsigned int h = cast(unsigned int, l);  /* seed */
  80   size_t step = (l>>5)+1;  /* if string is too long, don't hash all its chars */
  81   size_t l1;
  82   for (l1=l; l1>=step; l1-=step)  /* compute hash */
  83     h = h ^ ((h<<5)+(h>>2)+cast(unsigned char, str[l1-1]));
  84   for (o = G(L)->strt.hash[lmod(h, G(L)->strt.size)];
  85        o != NULL;
  86        o = o->gch.next) {
  87     TString *ts = rawgco2ts(o);
  88     if (ts->tsv.len == l && (memcmp(str, getstr(ts), l) == 0)) {
  89       /* string may be dead */
  90       if (isdead(G(L), o)) changewhite(o);
  91       return ts;
  92     }
  93   }
  94   return newlstr(L, str, l, h);  /* not found */
  95 }
  96
  97
  98 Udata *luaS_newudata (lua_State *L, size_t s, Table *e) {
  99   Udata *u;
 100   if (s > MAX_SIZET - sizeof(Udata))
 101     luaM_toobig(L);
 102   u = cast(Udata *, luaM_malloc(L, s + sizeof(Udata)));
 103   u->uv.marked = luaC_white(G(L));  /* is not finalized */
 104   u->uv.tt = LUA_TUSERDATA;
 105   u->uv.len = s;
 106   u->uv.metatable = NULL;
 107   u->uv.env = e;
 108   /* chain it on udata list (after main thread) */
 109   u->uv.next = G(L)->mainthread->next;
 110   G(L)->mainthread->next = obj2gco(u);
 111   return u;
 112 }
 113