LXR linux/include/linux/textsearch.h

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