refactor: move trie back to own static library

trie/include/trie.h

@@ -0,0 +1,119 @@
+#ifndef AD3_TERNARYTRIE
+#define AD3_TERNARYTRIE
+
+#define ALPHABET_SIZE 256
+#define DELIMITER '\0'
+#define MAX(x, y) (((x) > (y)) ? (x) : (y))
+
+// Should not be higher than 254 or stuff will break
+#define TRIE_MAX_SKIP_SIZE 8
+
+/**
+ * The implementation of a Ternary Trie.
+ *
+ * Each node should be represented by a binary tree in order to reduce the
+ * memory usage.
+ */
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <string.h>
+
+static const char charset[] =
+    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+static const size_t charset_len = sizeof(charset) - 1;
+
+// Length of randomly generated keys
+#define RANDOM_KEY_LENGTH_SHORT 4
+#define RANDOM_KEY_LENGTH_LONG 16
+
+/**
+ * Type definition for the struct representing the current Trie.
+ *
+ * You can (and should) redefine this in your c-file with the concrete fields.
+ */
+typedef struct ttrie Trie;
+
+typedef enum entry_type { Redirect, Paste, Unknown } EntryType;
+
+typedef struct entry {
+  EntryType type;
+  char *string;
+} Entry;
+
+Entry *entry_new(EntryType type, const char *string);
+
+/**
+ * Allocate and initialize an empty Trie.
+ *
+ * @return a pointer to an empty Trie struct
+ */
+Trie *trie_init();
+
+/**
+ * Populate trie with entries stored in the given file.
+ *
+ * @param trie
+ * @param file_path path to file containing entries
+ * @return amount of entries added; -1 if an error occured
+ */
+int trie_populate(Trie *trie, const char *file_path);
+
+/**
+ * De-allocate a trie by freeing the memory occupied by this trie.
+ *
+ * @param trie which should be freed
+ */
+void trie_free(Trie *trie);
+
+/**
+ * Search for an entry in the trie.
+ *
+ * @param trie
+ * @param key key representing the entry
+ * @return pointer to entry; NULL if not found
+ */
+Entry *trie_search(Trie *trie, const char *key);
+
+/**
+ * Add a string to this trie.
+ *
+ * @param trie
+ * @param key key to represent entry with
+ * @param entry entry to add
+ * @return true if the trie was changed by this operation, false if it was
+ * already present
+ */
+bool trie_add(Trie *trie, const char *key, Entry *entry);
+
+bool trie_add_no_lock(Trie *trie, const char *key, Entry *entry);
+
+/**
+ * Add an entry by generating a random string as the key.
+ *
+ * @param trie
+ * @param entry entry to add
+ * @param secure whether to generate a longer, more secure random key
+ * @return the generated key
+ */
+char *trie_add_random(Trie *trie, Entry *entry, bool secure);
+
+/**
+ * Remove an entry from this trie given its key.
+ *
+ * @param trie
+ * @param key key representing entry
+ * @return true if the entry was present and has been removed, false if it was
+ * not present
+ */
+bool trie_remove(Trie *trie, const char *key);
+
+/**
+ * Returns the number of entries in this trie.
+ *
+ * @param trie
+ * @return the number of entries in this trie
+ */
+size_t trie_size(Trie *trie);
+
+#endif // AD3_TERNARYTRIE