PC Welt 2006 November (DVD)/PCWELT_11_2006.ISO/casper/filesystem.squashfs/usr/src/linux-headers-2.6.17-6/include/linux/textsearch.h

C/C++ Source or Header | 2006-08-11 | 4.7 KB | 183 lines

#ifndef __LINUX_TEXTSEARCH_H
#define __LINUX_TEXTSEARCH_H

#ifdef __KERNEL__

#include <linux/types.h>
#include <linux/list.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/slab.h>

struct ts_config;

/**
 * TS_AUTOLOAD - Automatically load textsearch modules when needed
 */
#define TS_AUTOLOAD    1

/**
 * struct ts_state - search state
 * @offset: offset for next match
 * @cb: control buffer, for persistant variables of get_next_block()
 */
struct ts_state
{
    unsigned int        offset;
    char            cb[40];
};

/**
 * struct ts_ops - search module operations
 * @name: name of search algorithm
 * @init: initialization function to prepare a search
 * @find: find the next occurrence of the pattern
 * @destroy: destroy algorithm specific parts of a search configuration
 * @get_pattern: return head of pattern
 * @get_pattern_len: return length of pattern
 * @owner: module reference to algorithm
 */
struct ts_ops
{
    const char        *name;
    struct ts_config *    (*init)(const void *, unsigned int, gfp_t);
    unsigned int        (*find)(struct ts_config *,
                    struct ts_state *);
    void            (*destroy)(struct ts_config *);
    void *            (*get_pattern)(struct ts_config *);
    unsigned int        (*get_pattern_len)(struct ts_config *);
    struct module        *owner;
    struct list_head    list;
};

/**
 * struct ts_config - search configuration
 * @ops: operations of chosen algorithm
 * @get_next_block: callback to fetch the next block to search in
 * @finish: callback to finalize a search
 */
struct ts_config
{
    struct ts_ops        *ops;

    /**
     * get_next_block - fetch next block of data
     * @consumed: number of bytes consumed by the caller
     * @dst: destination buffer
     * @conf: search configuration
     * @state: search state
     *
     * Called repeatedly until 0 is returned. Must assign the
     * head of the next block of data to &*dst and return the length
     * of the block or 0 if at the end. consumed == 0 indicates
     * a new search. May store/read persistant values in state->cb.
     */
    unsigned int        (*get_next_block)(unsigned int consumed,
                          const u8 **dst,
                          struct ts_config *conf,
                          struct ts_state *state);

    /**
     * finish - finalize/clean a series of get_next_block() calls
     * @conf: search configuration
     * @state: search state
     *
     * Called after the last use of get_next_block(), may be used
     * to cleanup any leftovers.
     */
    void            (*finish)(struct ts_config *conf,
                      struct ts_state *state);
};

/**
 * textsearch_next - continue searching for a pattern
 * @conf: search configuration
 * @state: search state
 *
 * Continues a search looking for more occurrences of the pattern.
 * textsearch_find() must be called to find the first occurrence
 * in order to reset the state.
 *
 * Returns the position of the next occurrence of the pattern or
 * UINT_MAX if not match was found.
 */
static inline unsigned int textsearch_next(struct ts_config *conf,
                       struct ts_state *state)
{
    unsigned int ret = conf->ops->find(conf, state);

    if (conf->finish)
        conf->finish(conf, state);

    return ret;
}

/**
 * textsearch_find - start searching for a pattern
 * @conf: search configuration
 * @state: search state
 *
 * Returns the position of first occurrence of the pattern or
 * UINT_MAX if no match was found.
 */
static inline unsigned int textsearch_find(struct ts_config *conf,
                       struct ts_state *state)
{
    state->offset = 0;
    return textsearch_next(conf, state);
}

/**
 * textsearch_get_pattern - return head of the pattern
 * @conf: search configuration
 */
static inline void *textsearch_get_pattern(struct ts_config *conf)
{
    return conf->ops->get_pattern(conf);
}

/**
 * textsearch_get_pattern_len - return length of the pattern
 * @conf: search configuration
 */
static inline unsigned int textsearch_get_pattern_len(struct ts_config *conf)
{
    return conf->ops->get_pattern_len(conf);
}

extern int textsearch_register(struct ts_ops *);
extern int textsearch_unregister(struct ts_ops *);
extern struct ts_config *textsearch_prepare(const char *, const void *,
                        unsigned int, gfp_t, int);
extern void textsearch_destroy(struct ts_config *conf);
extern unsigned int textsearch_find_continuous(struct ts_config *,
                           struct ts_state *,
                           const void *, unsigned int);


#define TS_PRIV_ALIGNTO    8
#define TS_PRIV_ALIGN(len) (((len) + TS_PRIV_ALIGNTO-1) & ~(TS_PRIV_ALIGNTO-1))

static inline struct ts_config *alloc_ts_config(size_t payload,
                        gfp_t gfp_mask)
{
    struct ts_config *conf;

    conf = kmalloc(TS_PRIV_ALIGN(sizeof(*conf)) + payload, gfp_mask);
    if (conf == NULL)
        return ERR_PTR(-ENOMEM);

    memset(conf, 0, TS_PRIV_ALIGN(sizeof(*conf)) + payload);
    return conf;
}

static inline void *ts_config_priv(struct ts_config *conf)
{
    return ((u8 *) conf + TS_PRIV_ALIGN(sizeof(struct ts_config)));
}

#endif /* __KERNEL__ */

#endif