variable.c: avoid `mrb_undef_value()` for delete entries.
Instead embed deleted flag in the key (`mrb_sym` only occupies 30bits).
MODIFY
src/variable.c
src/variable.c
@@ -18,6 +18,10 @@ typedef struct iv_tbl {
mrb_value *ptr;
} iv_tbl;
+#define IV_EMPTY 0
+#define IV_DELETED (1<<31)
+#define IV_KEY_P(k) (((k)&~((uint32_t)IV_DELETED))!=0)
+
/* Creates the instance variable table. */
static iv_tbl*
iv_new(mrb_state *mrb)
@@ -50,16 +54,13 @@ iv_rehash(mrb_state *mrb, iv_tbl *t)
mrb_sym *keys = (mrb_sym*)&old_ptr[old_alloc];
mrb_value *vals = old_ptr;
for (size_t i = 0; i < old_alloc; i++) {
- /* key = 0 means empty; val = undef means deleted */
- if (keys[i] != 0 && !mrb_undef_p(vals[i])) {
+ if (IV_KEY_P(keys[i])) {
iv_put(mrb, t, keys[i], vals[i]);
}
}
mrb_free(mrb, old_ptr);
}
-#define slot_empty_p(k,v) ((k) == 0 && !mrb_undef_p(v))
-
/* Set the value for the symbol in the instance variable table. */
static void
iv_put(mrb_state *mrb, iv_tbl *t, mrb_sym sym, mrb_value val)
@@ -81,12 +82,12 @@ iv_put(mrb_state *mrb, iv_tbl *t, mrb_sym sym, mrb_value val)
vals[pos] = val;
return;
}
- else if (slot_empty_p(keys[pos], vals[pos])) {
+ else if (keys[pos] == IV_EMPTY) {
keys[pos] = sym;
vals[pos] = val;
return;
}
- else if (dpos < 0 && mrb_undef_p(vals[pos])) { /* deleted */
+ else if (keys[pos] == IV_DELETED && dpos < 0) {
dpos = pos;
}
pos = (pos+1) & (t->alloc-1);
@@ -123,7 +124,7 @@ iv_get(mrb_state *mrb, iv_tbl *t, mrb_sym sym, mrb_value *vp)
if (vp) *vp = vals[pos];
return TRUE;
}
- else if (slot_empty_p(keys[pos], vals[pos])) {
+ else if (keys[pos] == IV_EMPTY) {
return FALSE;
}
pos = (pos+1) & (t->alloc-1);
@@ -149,11 +150,10 @@ iv_del(mrb_state *mrb, iv_tbl *t, mrb_sym sym, mrb_value *vp)
for (;;) {
if (keys[pos] == sym) {
if (vp) *vp = vals[pos];
- keys[pos] = 0;
- vals[pos] = mrb_undef_value();
+ keys[pos] = IV_DELETED;
return TRUE;
}
- else if (slot_empty_p(keys[pos], vals[pos])) {
+ else if (keys[pos] == IV_EMPTY) {
return FALSE;
}
pos = (pos+1) & (t->alloc-1);
@@ -175,7 +175,7 @@ iv_foreach(mrb_state *mrb, iv_tbl *t, mrb_iv_foreach_func *func, void *p)
mrb_sym *keys = (mrb_sym*)&t->ptr[t->alloc];
mrb_value *vals = t->ptr;
for (i=0; i<t->alloc; i++) {
- if (keys[i] && !mrb_undef_p(vals[i])) {
+ if (IV_KEY_P(keys[i])) {
if ((*func)(mrb, keys[i], vals[i], p) != 0) {
return;
}
@@ -207,7 +207,7 @@ iv_copy(mrb_state *mrb, iv_tbl *t)
mrb_value *vals = t->ptr;
t2 = iv_new(mrb);
for (i=0; i<t->alloc; i++) {
- if (keys[i] && !mrb_undef_p(vals[i])) {
+ if (IV_KEY_P(keys[i])) {
iv_put(mrb, t2, keys[i], vals[i]);
}
}

variable.c: avoid `mrb_undef_value()` for delete entries.

Instead embed deleted flag in the key (`mrb_sym` only occupies 30bits).