feat(lsm): implement bt remove

lsm/include/lsm.h

@@ -29,9 +29,7 @@ typedef struct lsm_string {
  * The type of an attribute. Each type is represented as a single bit of a
  * 32-bit integer, so they can be easily combined into a bitmap.
  */
-typedef enum lsm_attr_type {
-  lsm_attr_type_entry_type = 1 << 0
-} lsm_attr_type;
+typedef enum lsm_attr_type { lsm_attr_type_entry_type = 1 << 0 } lsm_attr_type;
 
 /**
  * A single attribute associated with an entry

lsm/src/bt/lsm_bt.c

@@ -17,6 +17,20 @@ lsm_error lsm_bt_node_init(lsm_bt_node **ptr, const char key, void *data) {
   return lsm_error_ok;
 }
 
+void lsm_bt_node_free(lsm_bt_node *node) { free(node); }
+
+void lsm_bt_node_free_recursive(lsm_bt_node *node) {
+  if (node->left != NULL) {
+    lsm_bt_node_free_recursive(node->left);
+  }
+
+  if (node->right != NULL) {
+    lsm_bt_node_free_recursive(node->right);
+  }
+
+  lsm_bt_node_free(node);
+}
+
 lsm_error lsm_bt_init(lsm_bt **ptr) {
   lsm_bt *bt = calloc(1, sizeof(lsm_bt));
 
@@ -29,16 +43,24 @@ lsm_error lsm_bt_init(lsm_bt **ptr) {
   return lsm_error_ok;
 }
 
+void lsm_bt_free(lsm_bt *bt) {
+  if (bt->root != NULL) {
+    lsm_bt_node_free_recursive(bt->root);
+  }
+
+  free(bt);
+}
+
 lsm_error lsm_bt_insert(lsm_bt *bt, char key, void *data) {
   lsm_bt_node **dest = &bt->root;
 
   // Traverse down the tree until we reach the new point to insert our node
-  while (*dest != NULL) {
-    if ((*dest)->key == key) {
-      return lsm_error_already_present;
+  while ((*dest != NULL) && ((*dest)->key != key)) {
+    dest = key < (*dest)->key ? &(*dest)->left : &(*dest)->right;
   }
 
-    dest = key < (*dest)->key ? &(*dest)->left : &(*dest)->right;
+  if (*dest != NULL) {
+    return lsm_error_already_present;
   }
 
   lsm_bt_node *node;
@@ -56,15 +78,56 @@ lsm_error lsm_bt_insert(lsm_bt *bt, char key, void *data) {
 lsm_error lsm_bt_search(void **out, lsm_bt *bt, char key) {
   lsm_bt_node *node = bt->root;
 
-  while (node != NULL) {
-    if (node->key == key) {
+  while ((node != NULL) && (node->key != key)) {
+    node = key < node->key ? node->left : node->right;
+  }
+
+  if (node == NULL) {
+    return lsm_error_not_found;
+  }
+
   *out = node->data;
 
   return lsm_error_ok;
 }
 
-    node = key < node->key ? node->left : node->right;
-  }
-
+lsm_error lsm_bt_remove(void **out, lsm_bt *bt, char key) {
+  if (bt->root == NULL) {
     return lsm_error_not_found;
   }
+
+  lsm_bt_node **dest = &bt->root;
+
+  while ((*dest != NULL) && ((*dest)->key != key)) {
+    dest = key < (*dest)->key ? &(*dest)->left : &(*dest)->right;
+  }
+
+  if (*dest == NULL) {
+    return lsm_error_not_found;
+  }
+
+  *out = (*dest)->data;
+  bt->size--;
+
+  if (((*dest)->left != NULL) && ((*dest)->right != NULL)) {
+    lsm_bt_node **succ = &(*dest)->right;
+
+    while ((*succ)->left != NULL) {
+      succ = &(*succ)->left;
+    }
+
+    (*dest)->key = (*succ)->key;
+    (*dest)->data = (*succ)->data;
+
+    lsm_bt_node *succ_replacement = (*succ)->right;
+    lsm_bt_node_free(*succ);
+    *succ = succ_replacement;
+  } else {
+    lsm_bt_node *replacement =
+        (*dest)->left != NULL ? (*dest)->left : (*dest)->right;
+    lsm_bt_node_free(*dest);
+    *dest = replacement;
+  }
+
+  return lsm_error_ok;
+}

lsm/src/bt/lsm_bt.h

@@ -68,11 +68,13 @@ lsm_error lsm_bt_search(void **out, lsm_bt *bt, char key);
 lsm_error lsm_bt_insert(lsm_bt *bt, char key, void *data);
 
 /**
- * Remove the given key from the binary tree.
+ * Remove the given key from the binary tree. Ownership of the data pointer is
+ * returned to the caller.
  *
+ * @param out address to write data pointer to
  * @param bt binary tree to remove from
  * @param key key to remove
  */
-lsm_error lsm_bt_remove(lsm_bt *bt, char key);
+lsm_error lsm_bt_remove(void **out, lsm_bt *bt, char key);
 
 #endif

lsm/src/lsm_store.c

@@ -6,7 +6,8 @@
 /**
  * Initialize a new lsm_store struct.
  *
- * @param lsm_store pointer to where to store the newly allocated object's pointer
+ * @param lsm_store pointer to where to store the newly allocated object's
+ * pointer
  * @return success of the function
  */
 lsm_error lsm_store_init(lsm_store **ptr) {

lsm/src/lsm_store_node.c

@@ -1,7 +1,7 @@
 #include <stdlib.h>
 
-#include "lsm_store_node.h"
 #include "lsm.h"
+#include "lsm_store_node.h"
 
 lsm_error lsm_store_inode_init(lsm_store_inode **ptr, const char c) {
   lsm_store_inode *node = calloc(1, sizeof(lsm_store_inode));
@@ -28,7 +28,8 @@ lsm_error lsm_store_node_init(lsm_store_node **ptr) {
   return lsm_error_ok;
 }
 
-lsm_error lsm_store_node_search(lsm_store_node **out_ptr, lsm_store_node *node, const char c) {
+lsm_error lsm_store_node_search(lsm_store_node **out_ptr, lsm_store_node *node,
+                                const char c) {
   if (node->size == 0) {
     return lsm_error_not_found;
   }

lsm/src/lsm_store_node.h

@@ -37,6 +37,7 @@ lsm_error lsm_store_node_init(lsm_store_node **out);
 /**
  * Search for the next node following the given character, if present.
  */
-lsm_error lsm_store_node_search(lsm_store_node **out, lsm_store_node *node, const char c);
+lsm_error lsm_store_node_search(lsm_store_node **out, lsm_store_node *node,
+                                const char c);
 
 #endif

lsm/test/bt/bt.c

@@ -9,6 +9,7 @@
 
 void test_init() {
   BT_INIT();
+  lsm_bt_free(bt);
 }
 
 void test_insert_first() {
@@ -22,6 +23,8 @@ void test_insert_first() {
   TEST_CHECK(data == (void *)1);
 
   TEST_CHECK(lsm_bt_search(&data, bt, 'b') == lsm_error_not_found);
+
+  lsm_bt_free(bt);
 }
 
 void test_insert_two() {
@@ -38,6 +41,8 @@ void test_insert_two() {
   TEST_CHECK(lsm_bt_search(&data, bt, 'b') == lsm_error_ok);
   TEST_CHECK(data == (void *)2);
   TEST_CHECK(lsm_bt_search(&data, bt, 'c') == lsm_error_not_found);
+
+  lsm_bt_free(bt);
 }
 
 void test_insert_multiple() {
@@ -56,6 +61,42 @@ void test_insert_multiple() {
     TEST_CHECK(lsm_bt_search(&data, bt, chars[i]) == lsm_error_ok);
     TEST_CHECK(data == (void *)(i + 1));
   }
+
+  lsm_bt_free(bt);
+}
+
+void test_remove_root() {
+  BT_INIT();
+
+  TEST_CHECK(lsm_bt_insert(bt, 'a', (void *)1) == lsm_error_ok);
+
+  void *data;
+  TEST_CHECK(lsm_bt_remove(&data, bt, 'a') == lsm_error_ok);
+  TEST_CHECK(data == (void *)1);
+  TEST_CHECK(bt->root == NULL);
+
+  lsm_bt_free(bt);
+}
+
+void test_remove_multiple() {
+  char chars[] = "falcoep";
+  size_t char_count = sizeof(chars) / sizeof(char);
+
+  BT_INIT();
+
+  for (size_t i = 0; i < char_count; i++) {
+    TEST_CHECK(lsm_bt_insert(bt, chars[i], (void *)(i + 1)) == lsm_error_ok);
+  }
+
+  void *data;
+  TEST_CHECK(lsm_bt_remove(&data, bt, 'l') == lsm_error_ok);
+  TEST_CHECK(data == (void *)3);
+  TEST_CHECK(lsm_bt_remove(&data, bt, 'l') == lsm_error_not_found);
+  TEST_CHECK(lsm_bt_remove(&data, bt, 'e') == lsm_error_ok);
+  TEST_CHECK(data == (void *)6);
+  TEST_CHECK(lsm_bt_remove(&data, bt, 'e') == lsm_error_not_found);
+
+  lsm_bt_free(bt);
 }
 
 TEST_LIST = {
@@ -63,5 +104,7 @@ TEST_LIST = {
   { "test insert first", test_insert_first },
   { "test insert two", test_insert_two },
   { "test insert multiple", test_insert_multiple },
+  { "test remove root", test_remove_root },
+  { "test remove multiple", test_remove_multiple },
   { NULL, NULL }
 };