make RNG API (officially) public

Fixes #189

Signed-off-by: Steffen Jaeckel <jaeckel-floss@eyet-services.de>

strophe.h

@@ -535,6 +535,58 @@ void xmpp_base64_decode_bin(xmpp_ctx_t *ctx,
                             unsigned char **out,
                             size_t *outlen);
 
+/* RNG */
+
+typedef struct _xmpp_rand_t xmpp_rand_t;
+
+/** Create new xmpp_rand_t object.
+ *
+ *  @param ctx A Strophe context object
+ *
+ *  @ingroup Random
+ */
+xmpp_rand_t *xmpp_rand_new(xmpp_ctx_t *ctx);
+
+/** Destroy an xmpp_rand_t object.
+ *
+ *  @param ctx A Strophe context object
+ *  @param rand A xmpp_rand_t object
+ *
+ *  @ingroup Random
+ */
+void xmpp_rand_free(xmpp_ctx_t *ctx, xmpp_rand_t *rand);
+
+/** Generate random integer.
+ *  Analogue of rand(3).
+ *
+ *  @ingroup Random
+ */
+int xmpp_rand(xmpp_rand_t *rand);
+
+/** Generate random bytes.
+ *  Generates len bytes and stores them to the output buffer.
+ *
+ *  @param rand A xmpp_rand_t object
+ *  @param output A buffer where a len random bytes will be placed.
+ *  @param len Number of bytes reserved for the output..
+ *
+ *  @ingroup Random
+ */
+void xmpp_rand_bytes(xmpp_rand_t *rand, unsigned char *output, size_t len);
+
+/** Generate a nonce that is printable randomized string.
+ *  This function doesn't allocate memory and doesn't fail.
+ *
+ *  @param rand A xmpp_rand_t object
+ *  @param output A buffer where a NULL-terminated string will be placed.
+ *                The string will contain len-1 printable symbols.
+ *  @param len Number of bytes reserved for the output string, including
+ *             end of line '\0'.
+ *
+ *  @ingroup Random
+ */
+void xmpp_rand_nonce(xmpp_rand_t *rand, char *output, size_t len);
+
 #ifdef __cplusplus
 }
 #endif