Add initial implementation of a reference counting trie.

2018-04-06 23:55:56 -07:00
parent dabab1e870
commit 1960ded070
3 changed files with 170 additions and 1 deletions
--- a/src/ref_trie.c
+++ b/src/ref_trie.c
@@ -0,0 +1,89 @@
+#include "ref_trie.h"
+#include <stdlib.h>
+
+void libab_ref_trie_init(libab_ref_trie* trie) {
+    libab_ref_null(&trie->null_ref);
+    trie->head = NULL;
+}
+
+libab_result _libab_ref_trie_put(libab_ref_trie_node** node, const char* key, libab_ref* ref) {
+    libab_result result = LIBAB_SUCCESS;
+    if((*node = malloc(sizeof(**node)))) {
+        (*node)->key = *key;
+        (*node)->next = NULL;
+
+        if(*(key + 1)) {
+            libab_ref_null(&(*node)->ref);
+            result = _libab_ref_trie_put(&(*node)->child, key + 1, ref);
+        } else {
+            libab_ref_copy(ref, &(*node)->ref);
+            (*node)->child = NULL;
+        }
+    } else {
+        result = LIBAB_MALLOC;
+    }
+
+    if(result != LIBAB_SUCCESS) {
+        if(*node) libab_ref_free(&(*node)->ref);
+        free(*node);
+        *node = NULL;
+    }
+
+    return result;
+}
+
+libab_result libab_ref_trie_put(libab_ref_trie* trie, const char* key, libab_ref* ref) {
+    libab_result result = LIBAB_SUCCESS;
+    libab_ref_trie_node** current = &trie->head;
+    char search;
+    while(*key) {
+        search = *key;
+        while(*current && (*current)->key != search) {
+            current = &(*current)->next;
+        }
+        if(*current) {
+            if(*(key + 1)) {
+                current = &(*current)->child;
+            } else {
+                libab_ref_free(&(*current)->ref);
+                libab_ref_copy(ref, &(*current)->ref);
+            }
+            key++;
+        } else {
+            result = _libab_ref_trie_put(current, key, ref);
+            break;
+        }
+    }
+    return result;
+}
+
+const libab_ref* libab_ref_trie_get(const libab_ref_trie* trie, const char* key) {
+    libab_ref_trie_node* current = trie->head;
+    while(current && *key) {
+        while(current && current->key != *key) {
+            current = current->next;
+        }
+        if(current == NULL) break;
+
+        if(*(key + 1)) {
+            current = current->child;
+            key++;
+        } else {
+            return &current->ref;
+        }
+    }
+    return &trie->null_ref;
+}
+
+void _libab_ref_trie_free(libab_ref_trie_node* node) {
+    if(node == NULL) return;
+    _libab_ref_trie_free(node->next);
+    _libab_ref_trie_free(node->child);
+    libab_ref_free(&node->ref);
+    free(node);
+}
+
+void libab_ref_trie_free(libab_ref_trie* trie) {
+    _libab_ref_trie_free(trie->head);
+    libab_ref_free(&trie->null_ref);
+}