Added hashset

tests/iterators/hashset.c

@@ -0,0 +1,70 @@
+// Checks if the hash set iterator can go back and forward in the hash set without
+// hitting invalid states or a null pointer. Check is done visually.
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include "../../src/hashset.h"
+
+HASHSET_GENERATE(hs, hash_set, static, , int)
+
+size_t inthash(int t)
+{
+    size_t a = t;
+    a += ~(a << 15);
+    a ^= (a >> 10);
+    a += (a << 3);
+    a ^= (a >> 6);
+    a += ~(a << 11);
+    a ^= (a >> 16);
+    return a;
+}
+
+int intcmp(int a, int b)
+{
+    return a - b;
+}
+
+int main(int argc, char const *argv[])
+{
+    size_t i;
+    int r;
+
+    // Initliazie hash set and add some elements
+    hash_set *hs = hs_new(10, 0.9, intcmp, inthash);
+    for (int i = 0; i < 10; i++)
+        hs_insert(hs, i);
+
+    // Initialize iterator
+    hash_set_iter iter;
+    hs_iter_new(&iter, hs);
+
+    // Make the iterator go back and forward
+    for (int j = 0; j < 4; j++)
+    {
+        while (hs_iter_next(&iter, &r, &i))
+            printf("C[%2d] = %2d\n", i, r);
+        printf("\n");
+        while (hs_iter_prev(&iter, &r, &i))
+            printf("C[%2d] = %2d\n", i, r);
+        printf("\n\n");
+    }
+
+    for (hs_iter_tostart(&iter); !hs_iter_end(&iter); /**/)
+    {
+        hs_iter_next(&iter, &r, &i);
+        printf("S[%2d] = %2d\n", i, r);
+    }
+
+    printf("\n");
+
+    for (hs_iter_toend(&iter); !hs_iter_start(&iter); /**/)
+    {
+        hs_iter_prev(&iter, &r, &i);
+        printf("S[%2d] = %2d\n", i, r);
+    }
+
+    hs_free(hs);
+
+    return 0;
+}