[mmh] / sbr / utils.c

/*
** utils.c -- various utility routines
**
** 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>
#include <fcntl.h>
#include <errno.h>

/*
** We allocate space for messages (msgs array)
** this number of elements at a time.
*/
#define MAXMSGS 256

/*
** 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;

        /* Some non-POSIX realloc()s don't cope with realloc(NULL,sz) */
        if (!ptr) {
                return mh_xmalloc(size);
        }

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

        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 == '/') {
                /* strip trailing slash */
                *cp = '\0';
        }

        return curwd;
}

/*
** add   -- If "s1" is NULL, this routine just creates a
**       -- copy of "s2" into newly malloc'ed memory.
**       -- (use getcpy() instead in this case)
**       --
**       -- 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;
}

/*
** folder_exists
**     Check to see if a folder exists.
*/
int
folder_exists(char *folder)
{
        struct stat st;
        int exists = 0;

        if (stat(folder, &st) == -1) {
                /*
                ** The folder either doesn't exist, or we hit an error.
                ** Either way return a failure.
                */
                exists = 0;
        } else {
                /* We can see a folder with the right name */
                exists = 1;
        }

        return exists;
}


/*
** create_folder
**     Check to see if a folder exists, if not, prompt the user to create it.
*/
void
create_folder(char *folder, int autocreate, void (*done_callback)(int))
{
        struct stat st;
        extern int errno;
        char *cp;

        if (stat(folder, &st) == -1) {
                if (errno != ENOENT)
                        adios(folder, "error on folder");
                if (autocreate == 0) {
                        /* ask before creating folder */
                        cp = concat("Create folder \"", folder, "\"? ", NULL);
                        if (!getanswer(cp))
                                done_callback(1);
                        free(cp);
                } else if (autocreate == -1) {
                        /* do not create, so exit */
                        done_callback(1);
                }
                if (!makedir(folder))
                        adios(NULL, "unable to create folder %s", folder);
        }
}

/*
** num_digits
**     Return the number of digits in a nonnegative integer.
*/
int
num_digits(int n)
{
        int ndigits = 0;

        /* Sanity check */
        if (n < 0)
                adios(NULL, "oops, num_digits called with negative value");

        if (n == 0)
                return 1;

        while (n) {
                n /= 10;
                ndigits++;
        }

        return ndigits;
}

/*
** Append a message arg to an array of them, resizing it if necessary.
** The function is written to suit the arg parsing code it was extracted
** from, and will probably be changed when the other code is cleaned up.
*/
void
app_msgarg(struct msgs_array *msgs, char *cp)
{
        if(msgs->size >= msgs->max)
                msgs->msgs = mh_xrealloc(msgs->msgs,
                                (msgs->max+=MAXMSGS)*sizeof(*msgs->msgs));
        msgs->msgs[msgs->size++] = cp;
}