lower_bound and upper_bound operations for set

Author: wwwvladislav

README.md

@@ -181,6 +181,8 @@ step                x    x    x    x    x                   x
 range               x    x    x    x    x                   x
 find                x    x    x    x    x                   x
 count                    x              x                   x
+lower_bound                             x                   
+upper_bound                             x                   
 erase               x    x    x    x    x                   x
 copy                x    x    x    x    x                   x
 begin               x    x    x    x    x                   x

ctl/set.h

@@ -244,6 +244,44 @@ JOIN(B, init)(T key, int color)
     return self;
 }
 
+static inline B*
+JOIN(A, lower_bound)(A* self, T key)
+{
+    B* node = self->root;
+    B* result = NULL;
+    while(node)
+    {
+        int diff = self->compare(&key, &node->key);
+        if(diff <= 0)
+        {
+            result = node;
+            node = node->l;
+        }
+        else
+            node = node->r;
+    }
+    return result;
+}
+
+static inline B*
+JOIN(A, upper_bound)(A* self, T key)
+{
+    B* node = self->root;
+    B* result = NULL;
+    while(node)
+    {
+        int diff = self->compare(&key, &node->key);
+        if(diff < 0)
+        {
+            result = node;
+            node = node->l;
+        }
+        else
+            node = node->r;
+    }
+    return result;
+}
+
 static inline B*
 JOIN(A, find)(A* self, T key)
 {

tests/func/test_set.cc

@@ -63,6 +63,8 @@ main(void)
             TEST_SWAP,
             TEST_COUNT,
             TEST_FIND,
+            TEST_LOWER_BOUND,
+            TEST_UPPER_BOUND,
             TEST_COPY,
             TEST_EQUAL,
             TEST_UNION,
@@ -177,6 +179,34 @@ main(void)
                 digi_free(&kd);
                 break;
             }
+            case TEST_LOWER_BOUND:
+            {
+                int key = TEST_RAND(TEST_MAX_SIZE);
+                digi kd = digi_init(key);
+                set_digi_node* aa = set_digi_lower_bound(&a, kd);
+                auto bb = b.lower_bound(DIGI(key));
+                if(bb == b.end())
+                    assert(set_digi_end(&a) == aa);
+                else
+                    assert(*bb->value == *aa->key.value);
+                CHECK(a, b);
+                digi_free(&kd);
+                break;
+            }
+            case TEST_UPPER_BOUND:
+            {
+                int key = TEST_RAND(TEST_MAX_SIZE);
+                digi kd = digi_init(key);
+                set_digi_node* aa = set_digi_upper_bound(&a, kd);
+                auto bb = b.upper_bound(DIGI(key));
+                if(bb == b.end())
+                    assert(set_digi_end(&a) == aa);
+                else
+                    assert(*bb->value == *aa->key.value);
+                CHECK(a, b);
+                digi_free(&kd);
+                break;
+            }
             case TEST_COPY:
             {
                 set_digi aa = set_digi_copy(&a);