Subversion Repositories Kolibri OS

Rev

Blame | Last modification | View Log | RSS feed

  1. /*
  2. ** $Id: lstring.c,v 2.19 2011/05/03 16:01:57 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.   int i;
  24.   stringtable *tb = &G(L)->strt;
  25.   /* cannot resize while GC is traversing strings */
  26.   luaC_runtilstate(L, ~bitmask(GCSsweepstring));
  27.   if (newsize > tb->size) {
  28.     luaM_reallocvector(L, tb->hash, tb->size, newsize, GCObject *);
  29.     for (i = tb->size; i < newsize; i++) tb->hash[i] = NULL;
  30.   }
  31.   /* rehash */
  32.   for (i=0; i<tb->size; i++) {
  33.     GCObject *p = tb->hash[i];
  34.     tb->hash[i] = NULL;
  35.     while (p) {  /* for each node in the list */
  36.       GCObject *next = gch(p)->next;  /* save next */
  37.       unsigned int h = lmod(gco2ts(p)->hash, newsize);  /* new position */
  38.       gch(p)->next = tb->hash[h];  /* chain it */
  39.       tb->hash[h] = p;
  40.       resetoldbit(p);  /* see MOVE OLD rule */
  41.       p = next;
  42.     }
  43.   }
  44.   if (newsize < tb->size) {
  45.     /* shrinking slice must be empty */
  46.     lua_assert(tb->hash[newsize] == NULL && tb->hash[tb->size - 1] == NULL);
  47.     luaM_reallocvector(L, tb->hash, tb->size, newsize, GCObject *);
  48.   }
  49.   tb->size = newsize;
  50. }
  51.  
  52.  
  53. static TString *newlstr (lua_State *L, const char *str, size_t l,
  54.                                        unsigned int h) {
  55.   size_t totalsize;  /* total size of TString object */
  56.   GCObject **list;  /* (pointer to) list where it will be inserted */
  57.   TString *ts;
  58.   stringtable *tb = &G(L)->strt;
  59.   if (l+1 > (MAX_SIZET - sizeof(TString))/sizeof(char))
  60.     luaM_toobig(L);
  61.   if (tb->nuse >= cast(lu_int32, tb->size) && tb->size <= MAX_INT/2)
  62.     luaS_resize(L, tb->size*2);  /* too crowded */
  63.   totalsize = sizeof(TString) + ((l + 1) * sizeof(char));
  64.   list = &tb->hash[lmod(h, tb->size)];
  65.   ts = &luaC_newobj(L, LUA_TSTRING, totalsize, list, 0)->ts;
  66.   ts->tsv.len = l;
  67.   ts->tsv.hash = h;
  68.   ts->tsv.reserved = 0;
  69.   memcpy(ts+1, str, l*sizeof(char));
  70.   ((char *)(ts+1))[l] = '\0';  /* ending 0 */
  71.   tb->nuse++;
  72.   return ts;
  73. }
  74.  
  75.  
  76. TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
  77.   GCObject *o;
  78.   unsigned int h = cast(unsigned int, l);  /* seed */
  79.   size_t step = (l>>5)+1;  /* if string is too long, don't hash all its chars */
  80.   size_t l1;
  81.   for (l1=l; l1>=step; l1-=step)  /* compute hash */
  82.     h = h ^ ((h<<5)+(h>>2)+cast(unsigned char, str[l1-1]));
  83.   for (o = G(L)->strt.hash[lmod(h, G(L)->strt.size)];
  84.        o != NULL;
  85.        o = gch(o)->next) {
  86.     TString *ts = rawgco2ts(o);
  87.     if (h == ts->tsv.hash &&
  88.         ts->tsv.len == l &&
  89.         (memcmp(str, getstr(ts), l * sizeof(char)) == 0)) {
  90.       if (isdead(G(L), o))  /* string is dead (but was not collected yet)? */
  91.         changewhite(o);  /* resurrect it */
  92.       return ts;
  93.     }
  94.   }
  95.   return newlstr(L, str, l, h);  /* not found; create a new string */
  96. }
  97.  
  98.  
  99. TString *luaS_new (lua_State *L, const char *str) {
  100.   return luaS_newlstr(L, str, strlen(str));
  101. }
  102.  
  103.  
  104. Udata *luaS_newudata (lua_State *L, size_t s, Table *e) {
  105.   Udata *u;
  106.   if (s > MAX_SIZET - sizeof(Udata))
  107.     luaM_toobig(L);
  108.   u = &luaC_newobj(L, LUA_TUSERDATA, sizeof(Udata) + s, NULL, 0)->u;
  109.   u->uv.len = s;
  110.   u->uv.metatable = NULL;
  111.   u->uv.env = e;
  112.   return u;
  113. }
  114.  
  115.