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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-05-08 20:43:38 +0200
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-05-19 14:27:34 +0200
commitfe5102f23da752870c9514d5ffe79b7f067f70c4 (patch)
tree7dd19dd16dfa79eebe5f78a847289c914454790d /include
parent087bdaa6f4c597626cc547b59b7764405f16c4a2 (diff)
Add string table implementation
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Diffstat (limited to 'include')
-rw-r--r--include/str_table.h76
1 files changed, 76 insertions, 0 deletions
diff --git a/include/str_table.h b/include/str_table.h
new file mode 100644
index 0000000..b0d83f1
--- /dev/null
+++ b/include/str_table.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#ifndef STR_TABLE_H
+#define STR_TABLE_H
+
+typedef struct str_bucket_t {
+ struct str_bucket_t *next;
+ char *str;
+ size_t index;
+} str_bucket_t;
+
+/**
+ * @struct str_table_t
+ *
+ * @brief A data structure that manages incremental, unique IDs for strings
+ *
+ * A string table allocates IDs for strings, and provides fast lookup for ID by
+ * string and string by ID.
+ */
+typedef struct {
+ str_bucket_t **buckets;
+ size_t num_buckets;
+
+ char **strings;
+ size_t num_strings;
+ size_t max_strings;
+} str_table_t;
+
+/**
+ * @brief Initialize a string table
+ *
+ * @memberof str_table_t
+ *
+ * @param size The number of hash table buckets to use internally
+ *
+ * @return Zero on success, -1 on failure (reports error to stderr)
+ */
+int str_table_init(str_table_t *table, size_t size);
+
+/**
+ * @brief Free all memory used by a string table
+ *
+ * @memberof str_table_t
+ *
+ * @param table A pointer to a string table object
+ */
+void str_table_cleanup(str_table_t *table);
+
+/**
+ * @brief Resolve a string to an incremental, unique ID
+ *
+ * @memberof str_table_t
+ *
+ * If the string is passed to this function for the first time, a new ID
+ * is allocated for the string.
+ *
+ * @param table A pointer to a string table object
+ * @param str A pointer to a string to resolve
+ * @param idx Returns the unique ID of the string
+ *
+ * @return Zero on success, -1 on failure (reports error to stderr)
+ */
+int str_table_get_index(str_table_t *table, const char *str, size_t *idx);
+
+/**
+ * @brief Resolve a unique ID to the string it represents
+ *
+ * @memberof str_table_t
+ *
+ * @param table A pointer to a string table object
+ * @param index The ID to resolve
+ *
+ * @return A pointer to the string or NULL if it hasn't been added yet
+ */
+const char *str_table_get_string(str_table_t *table, size_t index);
+
+#endif /* STR_TABLE_H */