/* Copyright (c) 2002-2018 Pigeonhole authors, see the included COPYING file

 */

/* Match-type ':contains'

 */

#include "lib.h"

#include "sieve-match-types.h"

#include "sieve-comparators.h"

#include "sieve-interpreter.h"

#include "sieve-match.h"

#include <string.h>

#include <stdio.h>

/*

 * Forward declarations

 */

static int mcht_contains_match_key

  (struct sieve_match_context *mctx, const char *val, size_t val_size,

    const char *key, size_t key_size);

/*

 * Match-type object

 */

const struct sieve_match_type_def contains_match_type = {

  SIEVE_OBJECT("contains",

    &match_type_operand, SIEVE_MATCH_TYPE_CONTAINS),

  .validate_context = sieve_match_substring_validate_context,

  .match_key = mcht_contains_match_key

};

/*

 * Match-type implementation

 */

/* FIXME: Naive substring match implementation. Should switch to more

 * efficient algorithm if large values need to be searched (e.g. message body).

 *

 * The inner loop polls the interpreter CPU time limit periodically so that a

 * single O(N*M) match on a large value cannot run for many times the

 * configured sieve_max_cpu_time (which is otherwise only checked between

 * bytecode operations).

 */

#define SIEVE_CONTAINS_CPU_CHECK_INTERVAL 4096

static int mcht_contains_match_key

(struct sieve_match_context *mctx, const char *val, size_t val_size,

  const char *key, size_t key_size)

{

  const struct sieve_comparator *cmp = mctx->comparator;

  const char *vend = (const char *) val + val_size;

  const char *kend = (const char *) key + key_size;

  const char *vp = val;

  const char *kp = key;

  unsigned int counter = 0;

  if ( val_size == 0 )

    return ( key_size == 0 ? 1 : 0 );

  if ( cmp->def == NULL || cmp->def->char_match == NULL )

    return 0;

  while ( (vp < vend) && (kp < kend) ) {

    if ( !cmp->def->char_match(cmp, &vp, vend, &kp, kend) )

      vp++;

    if ( ++counter >= SIEVE_CONTAINS_CPU_CHECK_INTERVAL ) {

      counter = 0;

      if ( sieve_runtime_cpu_limit_exceeded(mctx->runenv) ) {

        sieve_runtime_error(

          mctx->runenv, NULL,

          "execution exceeded CPU time limit");

        mctx->exec_status =

          SIEVE_EXEC_RESOURCE_LIMIT;

        return -1;

      }

    }

  }

  return ( kp == kend ? 1 : 0 );

}