FreeTDM: Add span iterator

Part of my ongoing effort to split ftdm_io.c into more manageable pieces.

This change (along with others in the future) allows decoupling of the
span registry and its users, in preparation of moving all span related
functions and data structures into ftdm_span.c.

Signed-off-by: Stefan Knoblich <stkn@openisdn.net>

libs/freetdm/src/include/freetdm.h

@@ -1589,6 +1589,7 @@ FT_DECLARE(ftdm_status_t) ftdm_usrmsg_set_raw_data(ftdm_usrmsg_t *usrmsg, void *
 
 /*! \brief Get iterator current value (depends on the iterator type)
  *  \note Channel iterators return a pointer to ftdm_channel_t
+ *        Span iterators return a pointer to ftdm_span_t
  *        Variable iterators return a pointer to the variable name (not the variable value)
  */
 FT_DECLARE(void *) ftdm_iterator_current(ftdm_iterator_t *iter);
@@ -1725,6 +1726,11 @@ FT_DECLARE(const char *) ftdm_span_get_name(const ftdm_span_t *span);
  */
 FT_DECLARE(ftdm_iterator_t *) ftdm_span_get_chan_iterator(const ftdm_span_t *span, ftdm_iterator_t *iter);
 
+/*! \brief Get iterator for spans
+ *  \param iter Optional iterator. You can reuse an old iterator (not previously freed) to avoid the extra allocation of a new iterator.
+ */
+FT_DECLARE(ftdm_iterator_t *) ftdm_get_span_iterator(ftdm_iterator_t *iter);
+
 /*! 
  * \brief Execute a text command. The text command output will be returned and must be free'd 
  *

libs/freetdm/src/include/private/ftdm_types.h

@@ -360,6 +360,7 @@ typedef ftdm_status_t (*ftdm_channel_sig_dtmf_t)(ftdm_channel_t *ftdmchan, const
 typedef enum {
 	FTDM_ITERATOR_VARS = 1,
 	FTDM_ITERATOR_CHANS,
+	FTDM_ITERATOR_SPANS,
 } ftdm_iterator_type_t;
 
 struct ftdm_iterator {