/*******************************************************************************

        copyright:      Copyright (c) 2006 Keinfarbton. All rights reserved

        license:        BSD style: $(LICENSE)

        version:        Initial release: October 2006

        author:         Keinfarbton & Kris

*******************************************************************************/

module tango.stdc.stringz;

/*********************************
 * Convert array of chars to a C-style 0 terminated string.
 * Providing a tmp will use that instead of the heap, where
 * appropriate.
 */

char* toStringz (char[] s, char[] tmp=null)
{
        static char[] empty = "\0";

        auto len = s.length;
        if (s.ptr)
            if (len is 0)
                s = empty;
            else
               if (s[len-1] != 0)
                  {
                  if (tmp.length <= len)
                      tmp = new char[len+1];
                  tmp [0..len] = s;
                  tmp [len] = 0;
                  s = tmp;
                  }
        return s.ptr;
}

/*********************************
 * Convert a series of char[] to C-style 0 terminated strings, using 
 * tmp as a workspace and dst as a place to put the resulting char*'s.
 * This is handy for efficiently converting multiple strings at once.
 *
 * Returns a populated slice of dst
 *
 * Since: 0.99.7
 */

char*[] toStringz (char[] tmp, char*[] dst, char[][] strings...)
{
        assert (dst.length >= strings.length);

        int len = strings.length;
        foreach (s; strings)
                 len += s.length;
        if (tmp.length < len)
            tmp.length = len;

        foreach (i, s; strings)
                {
                dst[i] = toStringz (s, tmp);
                tmp = tmp [s.length + 1 .. len];
                }
        return dst [0 .. strings.length];
}

/*********************************
 * Convert a C-style 0 terminated string to an array of char
 */

char[] fromStringz (char* s)
{
        return s ? s[0 .. strlenz(s)] : null;
}

/*********************************
 * Convert array of wchars s[] to a C-style 0 terminated string.
 */

wchar* toString16z (wchar[] s)
{
        if (s.ptr)
            if (! (s.length && s[$-1] is 0))
                   s = s ~ "\0"w;
        return s.ptr;
}

/*********************************
 * Convert a C-style 0 terminated string to an array of wchar
 */

wchar[] fromString16z (wchar* s)
{
        return s ? s[0 .. strlenz(s)] : null;
}

/*********************************
 * Convert array of dchars s[] to a C-style 0 terminated string.
 */

dchar* toString32z (dchar[] s)
{
        if (s.ptr)
            if (! (s.length && s[$-1] is 0))
                   s = s ~ "\0"d;
        return s.ptr;
}

/*********************************
 * Convert a C-style 0 terminated string to an array of dchar
 */

dchar[] fromString32z (dchar* s)
{
        return s ? s[0 .. strlenz(s)] : null;
}

/*********************************
 * portable strlen
 */

size_t strlenz(T) (T* s)
{
        size_t i;

        if (s)
            while (*s++)
                   ++i;
        return i;
}



debug (UnitTest)
{
        import tango.stdc.stdio;

        unittest
        {
        debug(string) printf("stdc.stringz.unittest\n");

        char* p = toStringz("foo");
        assert(strlenz(p) == 3);
        char foo[] = "abbzxyzzy";
        p = toStringz(foo[3..5]);
        assert(strlenz(p) == 2);

        char[] test = "\0";
        p = toStringz(test);
        assert(*p == 0);
        assert(p == test.ptr);
        }
}

