delete!

/*
 *  call-seq:
 *     str.delete!([other_str]+>)   => str or nil
 *  
 *  Performs a <code>delete</code> operation in place, returning <i>str</i>, or
 *  <code>nil</code> if <i>str</i> was not modified.
 */

static VALUE
rb_str_delete_bang(argc, argv, str)
    int argc;
    VALUE *argv;
    VALUE str;
{
    char *s, *send, *t;
    char squeez[256];
    int modify = 0;
    int init = 1;
    int i;

    if (argc < 1) {
        rb_raise(rb_eArgError, "wrong number of arguments");
    }
    for (i=0; i<argc; i++) {
        VALUE s = argv[i];

        StringValue(s);
        tr_setup_table(s, squeez, init);
        init = 0;
    }

    rb_str_modify(str);
    s = t = RSTRING(str)->ptr;
    if (!s || RSTRING(str)->len == 0) return Qnil;
    send = s + RSTRING(str)->len;
    while (s < send) {
        if (squeez[*s & 0xff])
            modify = 1;
        else
            *t++ = *s;
        s++;
    }
    *t = '\0';
    RSTRING(str)->len = t - RSTRING(str)->ptr;

    if (modify) return str;
    return Qnil;
}