lua/ltable.c

195 lines
4.0 KiB
C

/*
** $Id: ltable.c,v 1.19 1999/01/25 12:30:11 roberto Exp roberto $
** Lua tables (hash)
** See Copyright Notice in lua.h
*/
#include <stdlib.h>
#include "lauxlib.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "ltable.h"
#include "lua.h"
#define gcsize(n) (1+(n/16))
#define nuse(t) ((t)->nuse)
#define nodevector(t) ((t)->node)
#define TagDefault LUA_T_ARRAY;
static long int hashindex (TObject *ref) {
long int h;
switch (ttype(ref)) {
case LUA_T_NUMBER:
h = (long int)nvalue(ref);
break;
case LUA_T_STRING: case LUA_T_USERDATA:
h = (IntPoint)tsvalue(ref);
break;
case LUA_T_ARRAY:
h = (IntPoint)avalue(ref);
break;
case LUA_T_PROTO:
h = (IntPoint)tfvalue(ref);
break;
case LUA_T_CPROTO:
h = (IntPoint)fvalue(ref);
break;
case LUA_T_CLOSURE:
h = (IntPoint)clvalue(ref);
break;
default:
lua_error("unexpected type to index table");
h = 0; /* to avoid warnings */
}
return (h >= 0 ? h : -(h+1));
}
Node *luaH_present (Hash *t, TObject *key) {
int tsize = nhash(t);
long int h = hashindex(key);
int h1 = h%tsize;
Node *n = node(t, h1);
/* keep looking until an entry with "ref" equal to key or nil */
while ((ttype(ref(n)) == ttype(key)) ? !luaO_equalval(key, ref(n))
: ttype(ref(n)) != LUA_T_NIL) {
h1 += (h&(tsize-2)) + 1; /* double hashing */
if (h1 >= tsize) h1 -= tsize;
n = node(t, h1);
}
return n;
}
void luaH_free (Hash *frees) {
while (frees) {
Hash *next = (Hash *)frees->head.next;
L->nblocks -= gcsize(frees->nhash);
luaM_free(nodevector(frees));
luaM_free(frees);
frees = next;
}
}
static Node *hashnodecreate (int nhash) {
Node *v = luaM_newvector(nhash, Node);
int i;
for (i=0; i<nhash; i++)
ttype(ref(&v[i])) = ttype(val(&v[i])) = LUA_T_NIL;
return v;
}
Hash *luaH_new (int nhash) {
Hash *t = luaM_new(Hash);
nhash = luaO_redimension(nhash*3/2);
nodevector(t) = hashnodecreate(nhash);
nhash(t) = nhash;
nuse(t) = 0;
t->htag = TagDefault;
luaO_insertlist(&(L->roottable), (GCnode *)t);
L->nblocks += gcsize(nhash);
return t;
}
static int newsize (Hash *t) {
Node *v = t->node;
int size = nhash(t);
int realuse = 0;
int i;
for (i=0; i<size; i++) {
if (ttype(val(v+i)) != LUA_T_NIL)
realuse++;
}
return luaO_redimension((realuse+1)*2); /* +1 is the new element */
}
static void rehash (Hash *t) {
int nold = nhash(t);
Node *vold = nodevector(t);
int nnew = newsize(t);
int i;
nodevector(t) = hashnodecreate(nnew);
nhash(t) = nnew;
nuse(t) = 0;
for (i=0; i<nold; i++) {
Node *n = vold+i;
if (ttype(val(n)) != LUA_T_NIL) {
*luaH_present(t, ref(n)) = *n; /* copy old node to new hash */
nuse(t)++;
}
}
L->nblocks += gcsize(nnew)-gcsize(nold);
luaM_free(vold);
}
void luaH_set (Hash *t, TObject *ref, TObject *val) {
Node *n = luaH_present(t, ref);
if (ttype(ref(n)) != LUA_T_NIL)
*val(n) = *val;
else {
TObject buff = *val; /* rehash may invalidate this address */
if ((long)nuse(t)*3L > (long)nhash(t)*2L) {
rehash(t);
n = luaH_present(t, ref);
}
nuse(t)++;
*ref(n) = *ref;
*val(n) = buff;
}
}
static Node *hashnext (Hash *t, int i) {
Node *n;
int tsize = nhash(t);
if (i >= tsize)
return NULL;
n = node(t, i);
while (ttype(val(n)) == LUA_T_NIL) {
if (++i >= tsize)
return NULL;
n = node(t, i);
}
return n;
}
Node *luaH_next (Hash *t, TObject *r) {
if (ttype(r) == LUA_T_NIL)
return hashnext(t, 0);
else {
Node *n = luaH_present(t, r);
luaL_arg_check(ttype(val(n)) != LUA_T_NIL, 2, "key not found");
return hashnext(t, (n-(t->node))+1);
}
}
void luaH_setint (Hash *t, int ref, TObject *val) {
TObject index;
ttype(&index) = LUA_T_NUMBER;
nvalue(&index) = ref;
luaH_set(t, &index, val);
}
TObject *luaH_getint (Hash *t, int ref) {
TObject index;
ttype(&index) = LUA_T_NUMBER;
nvalue(&index) = ref;
return luaH_get(t, &index);
}