reverse_fprintf.c

/* Copyright (C) 2019 Red Hat Inc.
 *
 * Authors:
 *  Eduardo Habkost <ehabkost@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

char *reverse_fprintf(const char *format, const char *str)
{
    char *r = NULL;
    char *pattern = NULL;
    GRegex *re = NULL;
    GMatchInfo *match = NULL;

    pattern = g_strdup_printf(format, "(.*)");
    re = g_regex_new(pattern, G_REGEX_ANCHORED, 0, NULL);
    if (!re) {
        goto out;
    }
    if (!g_regex_match(re, str, 0, &match)) {
        goto out;
    }
    r = g_strdup(g_match_info_fetch(match, 1));

out:
    g_match_info_free(match);
    if (re) {
        g_regex_unref(re);
    }
    g_free(pattern);
    return r;
}