| /* |
| ** $Id: lstring.c,v 1.44 2000/10/26 12:47:05 roberto Exp roberto $ |
| ** String table (keeps all strings handled by Lua) |
| ** See Copyright Notice in lua.h |
| */ |
| |
| |
| #include <string.h> |
| |
| #include "lua.h" |
| |
| #include "lmem.h" |
| #include "lobject.h" |
| #include "lstate.h" |
| #include "lstring.h" |
| |
| |
| /* |
| ** type equivalent to TString, but with maximum alignment requirements |
| */ |
| union L_UTString { |
| TString ts; |
| union L_Umaxalign dummy; /* ensures maximum alignment for `local' udata */ |
| }; |
| |
| |
| |
| void luaS_init (lua_State *L) { |
| L->strt.hash = luaM_newvector(L, 1, TString *); |
| L->udt.hash = luaM_newvector(L, 1, TString *); |
| L->nblocks += 2*sizeof(TString *); |
| L->strt.size = L->udt.size = 1; |
| L->strt.nuse = L->udt.nuse = 0; |
| L->strt.hash[0] = L->udt.hash[0] = NULL; |
| } |
| |
| |
| void luaS_freeall (lua_State *L) { |
| LUA_ASSERT(L->strt.nuse==0, "non-empty string table"); |
| L->nblocks -= (L->strt.size + L->udt.size)*sizeof(TString *); |
| luaM_free(L, L->strt.hash); |
| LUA_ASSERT(L->udt.nuse==0, "non-empty udata table"); |
| luaM_free(L, L->udt.hash); |
| } |
| |
| |
| static unsigned long hash_s (const char *s, size_t l) { |
| unsigned long h = l; /* seed */ |
| size_t step = (l>>5)|1; /* if string is too long, don't hash all its chars */ |
| for (; l>=step; l-=step) |
| h = h ^ ((h<<5)+(h>>2)+(unsigned char)*(s++)); |
| return h; |
| } |
| |
| |
| void luaS_resize (lua_State *L, stringtable *tb, int newsize) { |
| TString **newhash = luaM_newvector(L, newsize, TString *); |
| int i; |
| for (i=0; i<newsize; i++) newhash[i] = NULL; |
| /* rehash */ |
| for (i=0; i<tb->size; i++) { |
| TString *p = tb->hash[i]; |
| while (p) { /* for each node in the list */ |
| TString *next = p->nexthash; /* save next */ |
| unsigned long h = (tb == &L->strt) ? p->u.s.hash : IntPoint(p->u.d.value); |
| int h1 = h&(newsize-1); /* new position */ |
| LUA_ASSERT(h%newsize == (h&(newsize-1)), |
| "a&(x-1) == a%x, for x power of 2"); |
| p->nexthash = newhash[h1]; /* chain it in new position */ |
| newhash[h1] = p; |
| p = next; |
| } |
| } |
| luaM_free(L, tb->hash); |
| L->nblocks += (newsize - tb->size)*sizeof(TString *); |
| tb->size = newsize; |
| tb->hash = newhash; |
| } |
| |
| |
| static void newentry (lua_State *L, stringtable *tb, TString *ts, int h) { |
| ts->nexthash = tb->hash[h]; /* chain new entry */ |
| tb->hash[h] = ts; |
| tb->nuse++; |
| if (tb->nuse > (lint32)tb->size && tb->size < MAX_INT/2) /* too crowded? */ |
| luaS_resize(L, tb, tb->size*2); |
| } |
| |
| |
| |
| TString *luaS_newlstr (lua_State *L, const char *str, size_t l) { |
| unsigned long h = hash_s(str, l); |
| int h1 = h & (L->strt.size-1); |
| TString *ts; |
| for (ts = L->strt.hash[h1]; ts; ts = ts->nexthash) { |
| if (ts->len == l && (memcmp(str, ts->str, l) == 0)) |
| return ts; |
| } |
| /* not found */ |
| ts = (TString *)luaM_malloc(L, sizestring(l)); |
| ts->marked = 0; |
| ts->nexthash = NULL; |
| ts->len = l; |
| ts->u.s.hash = h; |
| ts->u.s.constindex = 0; |
| memcpy(ts->str, str, l); |
| ts->str[l] = 0; /* ending 0 */ |
| L->nblocks += sizestring(l); |
| newentry(L, &L->strt, ts, h1); /* insert it on table */ |
| return ts; |
| } |
| |
| |
| TString *luaS_newudata (lua_State *L, size_t s, void *udata) { |
| union L_UTString *uts = (union L_UTString *)luaM_malloc(L, |
| (lint32)sizeof(union L_UTString)+s); |
| TString *ts = &uts->ts; |
| ts->marked = 0; |
| ts->nexthash = NULL; |
| ts->len = s; |
| ts->u.d.tag = 0; |
| ts->u.d.value = (udata == NULL) ? uts+1 : udata; |
| L->nblocks += sizestring(s); |
| /* insert it on table */ |
| newentry(L, &L->udt, ts, IntPoint(ts->u.d.value) & (L->udt.size-1)); |
| return ts; |
| } |
| |
| |
| TString *luaS_createudata (lua_State *L, void *udata, int tag) { |
| int h1 = IntPoint(udata) & (L->udt.size-1); |
| TString *ts; |
| for (ts = L->udt.hash[h1]; ts; ts = ts->nexthash) { |
| if (udata == ts->u.d.value && (tag == ts->u.d.tag || tag == LUA_ANYTAG)) |
| return ts; |
| } |
| /* not found */ |
| ts = luaS_newudata(L, 0, udata); |
| if (tag != LUA_ANYTAG) |
| ts->u.d.tag = tag; |
| return ts; |
| } |
| |
| |
| TString *luaS_new (lua_State *L, const char *str) { |
| return luaS_newlstr(L, str, strlen(str)); |
| } |
| |
| |
| TString *luaS_newfixed (lua_State *L, const char *str) { |
| TString *ts = luaS_new(L, str); |
| if (ts->marked == 0) ts->marked = FIXMARK; /* avoid GC */ |
| return ts; |
| } |
| |