Second Extended Filesystem (ext2) and other improvements (#33)

[lunaix-os.git] / lunaix-os / kernel / ds / btrie.c

diff --git a/lunaix-os/kernel/ds/btrie.c b/lunaix-os/kernel/ds/btrie.c
index fd173b9455c701b99ff60b12ed9ae7a3acb7b01c..72758fb4517d822bfcf8b5bc1dced14d2ed80bfe 100644 (file)
--- a/lunaix-os/kernel/ds/btrie.c
+++ b/lunaix-os/kernel/ds/btrie.c
@@ -16,14 +16,17 @@
 #define BTRIE_INSERT 1
 
 struct btrie_node*
-__btrie_traversal(struct btrie* root, uint32_t index, int options)
+__btrie_traversal(struct btrie* root, unsigned long index, int options)
 {
-    index = index >> root->truncated;
-    uint32_t lz = index ? ROUNDDOWN(31 - __builtin_clz(index), BTRIE_BITS) : 0;
-    uint32_t bitmask = ((1 << BTRIE_BITS) - 1) << lz;
-    uint32_t i = 0;
+    unsigned long lz;
+    unsigned long bitmask;
+    unsigned long i = 0;
     struct btrie_node* tree = root->btrie_root;
 
+    lz = index ? ICEIL(msbitl - clzl(index), root->order) : 0;
+    lz = lz * root->order;
+    bitmask = ((1 << root->order) - 1) << lz;
+
     // Time complexity: O(log_2(log_2(N))) where N is the index to lookup
     while (bitmask && tree) {
         i = (index & bitmask) >> lz;
@@ -49,24 +52,24 @@ __btrie_traversal(struct btrie* root, uint32_t index, int options)
         } else {
             tree = subtree;
         }
-        bitmask = bitmask >> BTRIE_BITS;
-        lz -= BTRIE_BITS;
+        bitmask = bitmask >> root->order;
+        lz -= root->order;
     }
 
     return tree;
 }
 
 void
-btrie_init(struct btrie* btrie, uint32_t trunc_bits)
+btrie_init(struct btrie* btrie, unsigned int order)
 {
     btrie->btrie_root = vzalloc(sizeof(struct btrie_node));
     llist_init_head(&btrie->btrie_root->nodes);
     llist_init_head(&btrie->btrie_root->children);
-    btrie->truncated = trunc_bits;
+    btrie->order = order;
 }
 
 void*
-btrie_get(struct btrie* root, uint32_t index)
+btrie_get(struct btrie* root, unsigned long index)
 {
     struct btrie_node* node = __btrie_traversal(root, index, 0);
     if (!node) {
@@ -76,35 +79,40 @@ btrie_get(struct btrie* root, uint32_t index)
 }
 
 void
-btrie_set(struct btrie* root, uint32_t index, void* data)
+btrie_set(struct btrie* root, unsigned long index, void* data)
 {
     struct btrie_node* node = __btrie_traversal(root, index, BTRIE_INSERT);
     node->data = data;
 }
 
 void
-__btrie_remove(struct btrie_node* node)
+__btrie_rm_recursive(struct btrie_node* node)
 {
     struct btrie_node* parent = node->parent;
+
     if (parent) {
         llist_delete(&node->siblings);
         llist_delete(&node->nodes);
         vfree(node);
-        if (llist_empty(&parent->children)) {
-            __btrie_remove(parent);
+        if (llist_empty(&parent->children) && !parent->data) {
+            __btrie_rm_recursive(parent);
         }
     }
 }
 
 void*
-btrie_remove(struct btrie* root, uint32_t index)
+btrie_remove(struct btrie* root, unsigned long index)
 {
     struct btrie_node* node = __btrie_traversal(root, index, 0);
     if (!node) {
         return 0;
     }
     void* data = node->data;
-    __btrie_remove(node);
+    if (!llist_empty(&node->children)) {
+        node->data = NULL;
+    } else {
+        __btrie_rm_recursive(node);
+    }
     return data;
 }