Add some additional docs and sentenials

base45.c

@@ -92,6 +92,12 @@ int base45_decode(unsigned char * dst, size_t * _max_dst_len, const char * src,
   size_t out_len = 0, max_dst_len;
   max_dst_len = _max_dst_len  ? *_max_dst_len : src_len;
 
+  if (dst == NULL && _max_dst_len == NULL)
+	return -2;
+
+  if (src == NULL)
+	return -2;
+
   if (src_len == 0)
 	src_len = strlen(src);
 

base45.h

@@ -10,7 +10,11 @@
    src			source data
    src_len		source length
 
-   If the encoded string is longer than *dst_lenOrNull the actual length will still be returned.
+   If the encoded string is longer than *dst_lenOrNull the actual length will still be returned. This
+   can be used in conjuction with a NULL destination to get the length of the buffer needed. (Though x3
+   is always safe).
+
+   The resulting buffer will be \0 terminated. This \0 does not count in the returned length.
 
    returns 0 on sucess.
 */
@@ -25,12 +29,19 @@ int base45_encode(char * dstOrNull, size_t *dst_lenOrNull, const unsigned char *
 			or NULL to skip writing.
    dst_lenOrNull	pointer to the length of the dstOrNull buffer; will return actual value.
    src			source data
-   src_len		source length or null (in which case the terminating \0 of the string is used).
+   src_len		source length or 0 (in which case the terminating \0 of the string is used).
+
+   If the encoded string is longer than *dst_lenOrNull the actual length will still be returned. This
+   can also be used, in combiantion with a NULL destination, to get the size of the buffer needed.
+
+   The decode is case-insensitive; and will give an error on unknown characters (including on \r 
+   and \n). If dst_lenOrNull is null; dstOrNull, when non-null, is assumed to be of a suitable
+   length. Having both null will result in an error (return value -2)
 
-   If the encoded string is longer than *dst_lenOrNull the actual length will still be returned.
+   The resulting buffer will not be \0 terminated.
 
    returns 0 on sucess. 
-   returns -1 on illegal values or impossible lengths.
+   returns -1 on illegal values or impossible lengths, -2 on illegal inputs.
 */
 
 int base45_decode(unsigned char * dstOrNull, size_t *dst_lenOrNull, const char * src, size_t src_len);