segtree: allocate memory for arrays on heap

Huge sets may cause stack to be exhausted.
So, put allocate memory for arrays in
interval_map_decompose() function on heap.

Signed-off-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Florian Westphal <fw@strlen.de>

diff --git a/src/segtree.c b/src/segtree.c
index 5b6cdd1d770db70e9b2faee7899fe29a79154d19..78657de1f7c9aa2eeecc48c7c3e851007780622b 100644 (file)
--- a/src/segtree.c
+++ b/src/segtree.c
@@ -608,12 +608,18 @@ static int expr_value_cmp(const void *p1, const void *p2)
 
 void interval_map_decompose(struct expr *set)
 {
-       struct expr *elements[set->size], *ranges[set->size * 2];
+       struct expr **elements, **ranges;
        struct expr *i, *next, *low = NULL, *end;
        unsigned int n, m, size;
        mpz_t range, p;
        bool interval;
 
+       if (set->size == 0)
+               return;
+
+       elements = xmalloc_array(set->size, sizeof(struct expr *));
+       ranges = xmalloc_array(set->size * 2, sizeof(struct expr *));
+
        mpz_init(range);
        mpz_init(p);
 
@@ -728,4 +734,7 @@ void interval_map_decompose(struct expr *set)
 
                compound_expr_add(set, i);
        }
+
+       xfree(ranges);
+       xfree(elements);
 }