C 正则库 Demo (regex, pcre)

例子为匹配ip地址

pcre库（perl正则）

/*
 * gcc pcre.c -o pcrec -lpcre
 */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <pcre/pcre.h>

int is_match (const char *src, const char *pattern)
{
    pcre *re;
    const char *error;
    int erroffset;
    int result;

    re = pcre_compile (pattern,       /* the pattern */
            0,       /* default options */
            &error,       /* for error message */
            &erroffset, /* for error offset */
            NULL);       /* use default character tables */

    /* Compilation failed: print the error message and exit */
    if (re == NULL) {
        printf ("PCRE compilation failed at offset %d: %s\n", erroffset, error);
        return -1;
    }

    result = pcre_exec (re,        /* the compiled pattern */
            NULL, /* no extra data - we didn't study the pattern */
            src, /* the src string */
            strlen (src), /* the length of the src */
            0,        /* start at offset 0 in the src */
            0,        /* default options */
            NULL, 0);

    /* If Matching failed: */
    if (result < 0) {
        free (re);
        return -1;
    }

    free (re);
    return result;
}


    int
main ( int argc, char *argv[] )
{
    const char *pattern = "^((25[0-5]|2[0-4]\\d|[01]?\\d?\\d)\\.){3}(25[0-5]|2[0-4]\\d|[01]?\\d?\\d)$";
    const char *src = "5250.222.0.12";
    const char *src1 = "127.0.0.1";

    int result = is_match(src, pattern);
    printf ("%s %s\n", src, result != 0? "not matched":"matched");
    result = is_match(src1, pattern);
    printf ("%s %s\n", src1, result != 0? "not matched":"matched");

    return EXIT_SUCCESS;
}                /* ----------  end of function main  ---------- */

 

参考：http://www.cnblogs.com/skillup/articles/1876216.html

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标准库demo（posix正则）

/*
 *gcc regex.c -o regex
 */
#include <stdio.h>
#include <stdlib.h>
#include <regex.h>
/*
 * Regular expressions  verification
 * If matched success: return 0
 */
int is_match(const char *src, const char *pattern)
{
    regex_t preg;
    char prbuf[200];
    int rc;

    rc = regcomp(&preg, pattern, REG_EXTENDED);
    if (rc != 0) {
        regerror(rc, &preg, prbuf, sizeof(prbuf));
        printf("Regex compile error: %s\n", prbuf);
    }
    rc = regexec(&preg, src, 0, 0,  0);
    return rc;
}
    int
main ( int argc, char *argv[] )
{
    const char *pattern = "^((25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])$";
    const char *src = "5250.222.0.12";
    const char *src1 = "127.0.0.1";
    int result = is_match(src, pattern);
    printf ("%s %s\n", src, result != 0? "not matched":"matched");
    result = is_match(src1, pattern);
    printf ("%s %s\n", src1, result != 0? "not matched":"matched");
    return EXIT_SUCCESS;
}                /* ----------  end of function main  ---------- */