From fe5102f23da752870c9514d5ffe79b7f067f70c4 Mon Sep 17 00:00:00 2001 From: David Oberhollenzer Date: Wed, 8 May 2019 20:43:38 +0200 Subject: Add string table implementation Signed-off-by: David Oberhollenzer --- include/str_table.h | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 include/str_table.h (limited to 'include') 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 */ -- cgit v1.2.3