MonetDB: out2in - Make a start with improving 'exp_is_false'.

[Aris Koning]

Changeset: 9618c02fab15 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=9618c02fab15
Modified Files:
        sql/server/rel_exp.c
Branch: out2in
Log Message:

Make a start with improving 'exp_is_false'.


diffs (109 lines):

diff --git a/sql/server/rel_exp.c b/sql/server/rel_exp.c
--- a/sql/server/rel_exp.c
+++ b/sql/server/rel_exp.c
@@ -1600,6 +1600,84 @@ exp_is_true(mvc *sql, sql_exp *e)
        return 0;
 }
 
+static inline bool
+exp_is_cmp_exp_is_false(mvc *sql, sql_exp* e) {
+    assert(e->type == e_cmp);
+    assert(e->semantics && (e->flag == cmp_equal || e->flag == cmp_notequal));
+    assert(e->f == NULL);
+    sql_exp* l = e->l;
+    sql_exp* r = e->r;
+    assert (l && r);
+
+    /* Handle 'v is x' and 'v is not x' expressions.
+     * Other cases in is-semantics are unspecified.
+     */
+    if (e->flag == cmp_equal) {
+        return (exp_is_null(sql, l) != exp_is_null(sql, r));
+    }
+    if (e->flag == cmp_notequal) {
+        return (exp_is_null(sql, l) == exp_is_null(sql, r));
+    }
+
+    return false;
+}
+
+static inline bool
+exp_single_bound_cmp_exp_is_false(mvc *sql, sql_exp* e) {
+    assert(e->type == e_cmp);
+    sql_exp* l = e->l;
+    sql_exp* r = e->r;
+    assert(e->f == NULL);
+    assert (l && r);
+
+    return exp_is_null(sql, l) || exp_is_null(sql, r);
+}
+
+static inline bool
+exp_two_sided_bound_cmp_exp_is_false(mvc *sql, sql_exp* e) {
+    assert(e->type == e_cmp);
+    sql_exp* v = e->l;
+    sql_exp* l = e->r;
+    sql_exp* h = e->r;
+    assert (v && l && h);
+
+    return exp_is_null(sql, l) || exp_is_null(sql, v) || exp_is_null(sql, h);
+}
+
+static inline bool
+exp_regular_cmp_exp_is_false(mvc *sql, sql_exp* e) {
+    assert(e->type == e_cmp);
+
+    if (e->semantics)   return exp_is_cmp_exp_is_false(sql, e);
+    if (e -> f)         return exp_two_sided_bound_cmp_exp_is_false(sql, e);
+    else                return exp_single_bound_cmp_exp_is_false(sql, e);
+}
+
+static inline bool
+exp_or_exp_is_false(mvc *sql, sql_exp* e) {
+    assert(e->type == e_cmp && e->flag == cmp_or);
+    return exp_is_false(sql, e->l) && exp_is_false(sql, e->r);
+}
+
+static inline bool
+exp_cmp_exp_is_false(mvc *sql, sql_exp* e) {
+    assert(e->type == e_cmp);
+
+    switch (e->flag) {
+    case cmp_gt:
+    case cmp_gte:
+    case cmp_lte:
+    case cmp_lt:
+    case cmp_equal:
+    case cmp_notequal:
+        return exp_regular_cmp_exp_is_false(sql, e);
+    case cmp_or:
+        return exp_or_exp_is_false(sql, e);
+    default:
+        return false;
+       }
+}
+
 int
 exp_is_false(mvc *sql, sql_exp *e) 
 {
@@ -1610,6 +1688,10 @@ exp_is_false(mvc *sql, sql_exp *e)
                        return atom_is_false(sql->args[e->flag]);
                }
        }
+       else if (e->type == e_cmp) {
+               return exp_cmp_exp_is_false(sql, e);
+       }
+
        return 0;
 }
 
@@ -1661,7 +1743,8 @@ exp_is_null(mvc *sql, sql_exp *e )
                node *n;
                list *l = e->l;
 
-               if (!r && l && list_length(l) == 2) {
+               if (!e->semantics /*exclude isnull() and similar 
null-semantics-respecting functions*/ &&
+                       !r && l && list_length(l) == 2) {
                        for (n = l->h; n && !r; n = n->next) 
                                r |= exp_is_null(sql, n->data);
                }
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