/*
 * utils.c -- various utility routines
 *
 * $Id$
 *
 * This code is Copyright (c) 2006, by the authors of nmh.  See the
 * COPYRIGHT file in the root directory of the nmh distribution for
 * complete copyright information.
 */

#include <h/mh.h>
#include <h/utils.h>
#include <stdlib.h>

/*
 * Safely call malloc
 */
void *
mh_xmalloc(size_t size)
{
    void *memory;

    if (size == 0)
        adios(NULL, "Tried to malloc 0 bytes");

    memory = malloc(size);
    if (!memory)
        adios(NULL, "Malloc failed");

    return memory;
}

/*
 * Safely call realloc
 */
void *
mh_xrealloc(void *ptr, size_t size)
{
    void *memory;

    if (size == 0)
        adios(NULL, "Tried to realloc 0bytes");

    memory = realloc(ptr, size);
    if (!memory)
        adios(NULL, "Realloc failed");

    return memory;
}

/*
 * Return the present working directory, if the current directory does not
 * exist, or is too long, make / the pwd.
 */
char *
pwd(void)
{
    register char *cp;
    static char curwd[PATH_MAX];

    if (!getcwd (curwd, PATH_MAX)) {
        admonish (NULL, "unable to determine working directory");
        if (!mypath || !*mypath
                || (strcpy (curwd, mypath), chdir (curwd)) == -1) {
            strcpy (curwd, "/");
            chdir (curwd);
        }
        return curwd;
    }

    if ((cp = curwd + strlen (curwd) - 1) > curwd && *cp == '/')
        *cp = '\0';

    return curwd;
}

/*
 * add   -- If "s1" is NULL, this routine just creates a
 *       -- copy of "s2" into newly malloc'ed memory.
 *       --
 *       -- If "s1" is not NULL, then copy the concatenation
 *       -- of "s1" and "s2" (note the order) into newly
 *       -- malloc'ed memory.  Then free "s1".
 */
char *
add (char *s2, char *s1)
{
    char *cp;
    size_t len1 = 0, len2 = 0;

    if (s1)
        len1 = strlen (s1);
    if (s2)
        len2 = strlen (s2);

    cp = mh_xmalloc (len1 + len2 + 1);

    /* Copy s1 and free it */
    if (s1) {
        memcpy (cp, s1, len1);
        free (s1);
    }

    /* Copy s2 */
    if (s2)
        memcpy (cp + len1, s2, len2);

    /* Now NULL terminate the string */
    cp[len1 + len2] = '\0';

    return cp;
}