PCRE2 C++ example with named capture groups

main.cpp

#define PCRE2_CODE_UNIT_WIDTH 8

#include <stdio.h>
#include <string.h>
#include <pcre2.h>

#define MY_PATTERN "\\[(?<hours>\\d+):(?<minutes>\\d+):(?<seconds>\\d+)(\\.(?<milliseconds>\\d+))?\\] \\<(?<nickname>\\w+)\\> (?<message>.*)"
#define MY_SUBJECT "[0:00:01] <Tsoding> forsenPls forsenPls forsenPls forsenPls forsenPls forsenPls forsenPls forsenPls forsenPls forsenPls"

const char *line_comps[] = {
    "hours",
    "minutes",
    "seconds",
    "milliseconds",
    "nickname",
    "message",
};
const size_t line_comps_count = sizeof(line_comps) / sizeof(line_comps[0]);

int main(int argc, char *argv[])
{
    PCRE2_SPTR pattern;
    pattern = (PCRE2_SPTR) MY_PATTERN;
    printf("Regex to use: %s\n", pattern);
    printf("Text to parse: %s\n", MY_SUBJECT);

    int errorcode = 0;
    PCRE2_SIZE erroroffset = 0;
    pcre2_code *re = pcre2_compile(pattern, strlen(MY_PATTERN), 0, &errorcode, &erroroffset, NULL);

    if (re == NULL) {
        PCRE2_UCHAR buffer[256];
        pcre2_get_error_message(errorcode, buffer, sizeof(buffer));
        printf("PCRE2 compilation failed at offset %d: %s\n", (int)erroroffset, buffer);
        exit(1);
    }

    PCRE2_SPTR subject = (PCRE2_SPTR) MY_SUBJECT;     /* the appropriate width (in this case, 8 bits). */
    size_t subject_length = strlen(MY_SUBJECT);

    pcre2_match_data *match_data = pcre2_match_data_create_from_pattern(re, NULL);

    int rc = pcre2_match(
        re,                   /* the compiled pattern */
        subject,              /* the subject string */
        subject_length,       /* the length of the subject */
        0,                    /* start at offset 0 in the subject */
        0,                    /* default options */
        match_data,           /* block for storing the result */
        NULL);                /* use default match context */

    if (rc < 0) {
        switch(rc) {
        case PCRE2_ERROR_NOMATCH:
            printf("No match\n");
            break;
        default:
            printf("Matching error %d\n", rc);
            break;
        }
        exit(1);
    }

    printf("rc = %d\n", rc);

    PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
    printf("Match succeeded at offset %d\n", (int)ovector[0]);

    for (size_t i = 0; i < line_comps_count; ++i) {
        int index = pcre2_substring_number_from_name(re, (PCRE2_SPTR) line_comps[i]);
        PCRE2_SPTR substring_start = subject + ovector[2*index];
        size_t substring_length = ovector[2*index+1] - ovector[2*index];
        printf("%s: %.*s\n", line_comps[i], (int)substring_length, (char *)substring_start);
    }

    return 0;
}