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committed 2874c5fd284/* ========================================================================== */// SPDX-License-Identifier: GPL-2.0-or-later/* * lib/textsearch.c Generic text search interface * * Authors: Thomas Graf <tgraf@suug.ch> * Pablo Neira Ayuso <pablo@netfilter.org> * * ========================================================================== */​/** * DOC: ts_intro * INTRODUCTION * * The textsearch infrastructure provides text searching facilities for * both linear and non-linear data. Individual search algorithms are * implemented in modules and chosen by the user. * * ARCHITECTURE * * .. code-block:: none * * User * +----------------+ * | finish()|<--------------(6)-----------------+ * |get_next_block()|<--------------(5)---------------+ | * | | Algorithm | | * | | +------------------------------+ * | | | init() find() destroy() | * | | +------------------------------+ * | | Core API ^ ^ ^ * | | +---------------+ (2) (4) (8) * | (1)|----->| prepare() |---+ | | * | (3)|----->| find()/next() |-----------+ | * | (7)|----->| destroy() |----------------------+ * +----------------+ +---------------+ * * (1) User configures a search by calling textsearch_prepare() specifying * the search parameters such as the pattern and algorithm name. * (2) Core requests the algorithm to allocate and initialize a search * configuration according to the specified parameters. * (3) User starts the search(es) by calling textsearch_find() or * textsearch_next() to fetch subsequent occurrences. A state variable * is provided to the algorithm to store persistent variables. * (4) Core eventually resets the search offset and forwards the find() * request to the algorithm. * (5) Algorithm calls get_next_block() provided by the user continuously * to fetch the data to be searched in block by block. * (6) Algorithm invokes finish() after the last call to get_next_block * to clean up any leftovers from get_next_block. (Optional) * (7) User destroys the configuration by calling textsearch_destroy(). * (8) Core notifies the algorithm to destroy algorithm specific * allocations. (Optional) * * USAGE * * Before a search can be performed, a configuration must be created * by calling textsearch_prepare() specifying the searching algorithm, * the pattern to look for and flags. As a flag, you can set TS_IGNORECASE * to perform case insensitive matching. But it might slow down * performance of algorithm, so you should use it at own your risk. * The returned configuration may then be used for an arbitrary * amount of times and even in parallel as long as a separate struct