linux/include/linux/textsearch.h
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   1#ifndef __LINUX_TEXTSEARCH_H
   2#define __LINUX_TEXTSEARCH_H
   3
   4#include <linux/types.h>
   5#include <linux/list.h>
   6#include <linux/kernel.h>
   7#include <linux/err.h>
   8#include <linux/slab.h>
   9
  10struct module;
  11
  12struct ts_config;
  13
  14#define TS_AUTOLOAD     1 /* Automatically load textsearch modules when needed */
  15#define TS_IGNORECASE   2 /* Searches string case insensitively */
  16
  17/**
  18 * struct ts_state - search state
  19 * @offset: offset for next match
  20 * @cb: control buffer, for persistent variables of get_next_block()
  21 */
  22struct ts_state
  23{
  24        unsigned int            offset;
  25        char                    cb[40];
  26};
  27
  28/**
  29 * struct ts_ops - search module operations
  30 * @name: name of search algorithm
  31 * @init: initialization function to prepare a search
  32 * @find: find the next occurrence of the pattern
  33 * @destroy: destroy algorithm specific parts of a search configuration
  34 * @get_pattern: return head of pattern
  35 * @get_pattern_len: return length of pattern
  36 * @owner: module reference to algorithm
  37 */
  38struct ts_ops
  39{
  40        const char              *name;
  41        struct ts_config *      (*init)(const void *, unsigned int, gfp_t, int);
  42        unsigned int            (*find)(struct ts_config *,
  43                                        struct ts_state *);
  44        void                    (*destroy)(struct ts_config *);
  45        void *                  (*get_pattern)(struct ts_config *);
  46        unsigned int            (*get_pattern_len)(struct ts_config *);
  47        struct module           *owner;
  48        struct list_head        list;
  49};
  50
  51/**
  52 * struct ts_config - search configuration
  53 * @ops: operations of chosen algorithm
  54 * @flags: flags
  55 * @get_next_block: callback to fetch the next block to search in
  56 * @finish: callback to finalize a search
  57 */
  58struct ts_config
  59{
  60        struct ts_ops           *ops;
  61        int                     flags;
  62
  63        /**
  64         * get_next_block - fetch next block of data
  65         * @consumed: number of bytes consumed by the caller
  66         * @dst: destination buffer
  67         * @conf: search configuration
  68         * @state: search state
  69         *
  70         * Called repeatedly until 0 is returned. Must assign the
  71         * head of the next block of data to &*dst and return the length
  72         * of the block or 0 if at the end. consumed == 0 indicates
  73         * a new search. May store/read persistent values in state->cb.
  74         */
  75        unsigned int            (*get_next_block)(unsigned int consumed,
  76                                                  const u8 **dst,
  77                                                  struct ts_config *conf,
  78                                                  struct ts_state *state);
  79
  80        /**
  81         * finish - finalize/clean a series of get_next_block() calls
  82         * @conf: search configuration
  83         * @state: search state
  84         *
  85         * Called after the last use of get_next_block(), may be used
  86         * to cleanup any leftovers.
  87         */
  88        void                    (*finish)(struct ts_config *conf,
  89                                          struct ts_state *state);
  90};
  91
  92/**
  93 * textsearch_next - continue searching for a pattern
  94 * @conf: search configuration
  95 * @state: search state
  96 *
  97 * Continues a search looking for more occurrences of the pattern.
  98 * textsearch_find() must be called to find the first occurrence
  99 * in order to reset the state.
 100 *
 101 * Returns the position of the next occurrence of the pattern or
 102 * UINT_MAX if not match was found.
 103 */ 
 104static inline unsigned int textsearch_next(struct ts_config *conf,
 105                                           struct ts_state *state)
 106{
 107        unsigned int ret = conf->ops->find(conf, state);
 108
 109        if (conf->finish)
 110                conf->finish(conf, state);
 111
 112        return ret;
 113}
 114
 115/**
 116 * textsearch_find - start searching for a pattern
 117 * @conf: search configuration
 118 * @state: search state
 119 *
 120 * Returns the position of first occurrence of the pattern or
 121 * UINT_MAX if no match was found.
 122 */ 
 123static inline unsigned int textsearch_find(struct ts_config *conf,
 124                                           struct ts_state *state)
 125{
 126        state->offset = 0;
 127        return textsearch_next(conf, state);
 128}
 129
 130/**
 131 * textsearch_get_pattern - return head of the pattern
 132 * @conf: search configuration
 133 */
 134static inline void *textsearch_get_pattern(struct ts_config *conf)
 135{
 136        return conf->ops->get_pattern(conf);
 137}
 138
 139/**
 140 * textsearch_get_pattern_len - return length of the pattern
 141 * @conf: search configuration
 142 */
 143static inline unsigned int textsearch_get_pattern_len(struct ts_config *conf)
 144{
 145        return conf->ops->get_pattern_len(conf);
 146}
 147
 148extern int textsearch_register(struct ts_ops *);
 149extern int textsearch_unregister(struct ts_ops *);
 150extern struct ts_config *textsearch_prepare(const char *, const void *,
 151                                            unsigned int, gfp_t, int);
 152extern void textsearch_destroy(struct ts_config *conf);
 153extern unsigned int textsearch_find_continuous(struct ts_config *,
 154                                               struct ts_state *,
 155                                               const void *, unsigned int);
 156
 157
 158#define TS_PRIV_ALIGNTO 8
 159#define TS_PRIV_ALIGN(len) (((len) + TS_PRIV_ALIGNTO-1) & ~(TS_PRIV_ALIGNTO-1))
 160
 161static inline struct ts_config *alloc_ts_config(size_t payload,
 162                                                gfp_t gfp_mask)
 163{
 164        struct ts_config *conf;
 165
 166        conf = kzalloc(TS_PRIV_ALIGN(sizeof(*conf)) + payload, gfp_mask);
 167        if (conf == NULL)
 168                return ERR_PTR(-ENOMEM);
 169
 170        return conf;
 171}
 172
 173static inline void *ts_config_priv(struct ts_config *conf)
 174{
 175        return ((u8 *) conf + TS_PRIV_ALIGN(sizeof(struct ts_config)));
 176}
 177
 178#endif
 179
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