linux-kernel - Re: [Code] Fastest String Search Algorithm.

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Date:   Sun, 13 Jun 2021 15:35:22 +0530
From:   Bhaskar Chowdhury <unixbhaskar@...il.com>
To:     Amit Choudhary <amitchoudhary0523@...il.com>
Cc:     LinuxKernel <linux-kernel@...r.kernel.org>
Subject: Re: [Code] Fastest String Search Algorithm.

On 14:00 Sun 13 Jun 2021, Amit Choudhary wrote:

Ahhhhhhhh...

Oh crap! Get off the lawn , kiddo. Do NOT USE THIS PLACE for your obnoxious
desire.

We don't have time and energy to evaluate some airy-fairy stuff .

How do you know we will ever bother to think about "include your code"?? Let
alone other factor...huh...you are living in fool's paradise ...meh... look
like your head is filled with lots of preconceived dogma....where have you got
those?? Heck..

Your intention is not wise...this mailing list solely exist for people
interested in Linux and only in Linux Kernel. Period.

IOW , PLEASE DO NOT BOTHER US.

~Bhaskar

>Hi All,
>
>I have invented a new string search algorithm. It has performed better
>than strstr(), Boyer-Moore, and KPM algorithms.
>
>But I am not sending my code so that my algorithm gets included in linux kernel.
>
>I am sending this code because linux kernel mailing list is in public
>domain and getting indexed by search engines. So, people can see this
>algo if they search for fastest string search algorithm on web.
>
>Code:
>
>===================================================================================
>
>// Choudhary string search algorithm
>static char * choudhary_string_search_algorithm(char *text, char *pattern)
>{
>
>#define false 0
>#define true 1
>#define ALPHABET_SIZE 256
>
>    int i = 0;
>    int end_index = 0;
>    int not_found = false;
>
>    char pattern_char[ALPHABET_SIZE] = {0};
>
>    int text_len = strlen(text);
>    int pattern_len = strlen(pattern);
>
>    int pi_44 = pattern_len - 1;
>    int pi_34 = (3 * pattern_len) / 4;
>    int pi_24 = pattern_len / 2;
>    int pi_14 = pattern_len / 4;
>
>    int last_failed_index = -1;
>
>    // preprocessing
>    for (i = 0; i < pattern_len; i++) {
>        pattern_char[(int)(pattern[i])] = 1;
>    }
>
>    // now search
>    for (i = 0; i < text_len; i++) {
>
>        if ((text_len - i) < pattern_len) {
>            return NULL;
>            //return -1;
>        }
>
>        if (pattern[pi_44] != text[i + pi_44]) {
>
>            last_failed_index = pi_44;
>
>            // this character doesn't appear in pattern, so skip
>            if (pattern_char[(int)(text[i + pi_44])] == 0) {
>                i = i + pi_44;
>            }
>
>            continue;
>
>        } else if (pattern[pi_34] != text[i + pi_34]) {
>
>            last_failed_index = pi_34;
>
>            // this character doesn't appear in pattern, so skip
>            if (pattern_char[(int)(text[i + pi_34])] == 0) {
>                i = i + pi_34;
>            }
>
>            continue;
>
>        } else if (pattern[pi_24] != text[i + pi_24]) {
>
>            last_failed_index = pi_24;
>
>            // this character doesn't appear in pattern, so skip
>            if (pattern_char[(int)(text[i + pi_24])] == 0) {
>                i = i + pi_24;
>            }
>
>            continue;
>
>        } else if (pattern[pi_14] != text[i + pi_14]) {
>
>            last_failed_index = pi_14;
>
>            // this character doesn't appear in pattern, so skip
>            if (pattern_char[(int)(text[i + pi_14])] == 0) {
>                i = i + pi_14;
>            }
>
>            continue;
>
>        } // end of if-else.. block
>
>        // compare with character at last failed index.
>        if (last_failed_index >= 0) {
>
>            if (pattern[last_failed_index] != text[i + last_failed_index]) {
>                continue;
>            }
>
>        }
>
>        if (pattern[0] == text[i]) {
>
>            //full_pattern_search = full_pattern_search + 1;
>            end_index = i + pi_44;
>            not_found = false;
>            int index = 0;
>
>            for (index = i; index <= end_index; index++) {
>                if (text[index] != pattern[index - i]) {
>                    last_failed_index = index - i;
>                    not_found = true;
>                    break;
>                }
>            } // end of inner for loop
>
>            if (not_found == false) { // match is found
>                return (text + i);
>                //return i;
>            } else if (pattern_char[(int)(text[index])] == 0) {
>                i = index;
>            }
>        } // end of if pattern[0]
>
>    } // end of outer for loop
>
>    return NULL;
>    //return -1;
>
>} // end of choudhary_string_search_algorithm
>
>===================================================================================
>
>Regards,
>Amit

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