segtree: refactor decomposition of closed intervals

Move the code in `interval_map_decompose` which adds a new closed
interval to the set into a separate function.  In addition to the moving
of the code, there is one other change: `compound_expr_add` is called
once, after the main conditional, instead of being called in each
branch.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Florian Westphal <fw@strlen.de>

1 files changed, 38 insertions, 33 deletions

diff --git a/src/segtree.c b/src/segtree.c
index c36497ce..d15c39f3 100644
--- a/src/segtree.c
+++ b/src/segtree.c
@@ -493,12 +493,48 @@ static struct expr *interval_to_range(struct expr *low, struct expr *i, mpz_t ra
 	return __expr_to_set_elem(low, tmp);
 }
 
+static void
+add_interval(struct expr *set, struct expr *low, struct expr *i)
+{
+	struct expr *expr;
+	mpz_t range, p;
+
+	mpz_init(range);
+	mpz_init(p);
+
+	mpz_sub(range, expr_value(i)->value, expr_value(low)->value);
+	mpz_sub_ui(range, range, 1);
+
+	mpz_and(p, expr_value(low)->value, range);
+
+	if (!mpz_cmp_ui(range, 0)) {
+		if (expr_basetype(low)->type == TYPE_STRING)
+			mpz_switch_byteorder(expr_value(low)->value,
+					     expr_value(low)->len / BITS_PER_BYTE);
+		low->flags |= EXPR_F_KERNEL;
+		expr = expr_get(low);
+	} else if (range_is_prefix(range) && !mpz_cmp_ui(p, 0)) {
+
+		if (i->dtype->flags & DTYPE_F_PREFIX)
+			expr = interval_to_prefix(low, i, range);
+		else if (expr_basetype(i)->type == TYPE_STRING)
+			expr = interval_to_string(low, i, range);
+		else
+			expr = interval_to_range(low, i, range);
+	} else
+		expr = interval_to_range(low, i, range);
+
+	compound_expr_add(set, expr);
+
+	mpz_clear(range);
+	mpz_clear(p);
+}
+
 void interval_map_decompose(struct expr *set)
 {
 	struct expr *i, *next, *low = NULL, *end, *catchall = NULL, *key;
 	struct expr **elements, **ranges;
 	unsigned int n, m, size;
-	mpz_t range, p;
 	bool interval;
 
 	if (set->size == 0)
@@ -507,9 +543,6 @@ void interval_map_decompose(struct expr *set)
 	elements = xmalloc_array(set->size, sizeof(struct expr *));
 	ranges = xmalloc_array(set->size * 2, sizeof(struct expr *));
 
-	mpz_init(range);
-	mpz_init(p);
-
 	/* Sort elements */
 	n = 0;
 	list_for_each_entry_safe(i, next, &set->expressions, list) {
@@ -568,32 +601,7 @@ void interval_map_decompose(struct expr *set)
 			}
 		}
 
-		mpz_sub(range, expr_value(i)->value, expr_value(low)->value);
-		mpz_sub_ui(range, range, 1);
-
-		mpz_and(p, expr_value(low)->value, range);
-
-		if (!mpz_cmp_ui(range, 0)) {
-			if (expr_basetype(low)->type == TYPE_STRING)
-				mpz_switch_byteorder(expr_value(low)->value, expr_value(low)->len / BITS_PER_BYTE);
-			low->flags |= EXPR_F_KERNEL;
-			compound_expr_add(set, expr_get(low));
-		} else if (range_is_prefix(range) && !mpz_cmp_ui(p, 0)) {
-			struct expr *expr;
-
-			if (i->dtype->flags & DTYPE_F_PREFIX)
-				expr = interval_to_prefix(low, i, range);
-			else if (expr_basetype(i)->type == TYPE_STRING)
-				expr = interval_to_string(low, i, range);
-			else
-				expr = interval_to_range(low, i, range);
-
-			compound_expr_add(set, expr);
-		} else {
-			struct expr *expr = interval_to_range(low, i, range);
-
-			compound_expr_add(set, expr);
-		}
+		add_interval(set, low, i);
 
 		if (i->flags & EXPR_F_INTERVAL_END) {
 			expr_free(low);
@@ -633,9 +641,6 @@ out:
 	if (catchall)
 		compound_expr_add(set, catchall);
 
-	mpz_clear(range);
-	mpz_clear(p);
-
 	xfree(ranges);
 	xfree(elements);
 }