doc: Update stats_tree README

Update README.stats_tree including the sample implementation for
changes in the API, such as the enum return value and needing to
set the node datatype as either int or float.

Also update the comments in the stats_tree header to make it clear
that abbrev and name refer to the abbreviation used in the tshark -z
option, and the name of the menu and window in the GUI for the stats
tree.

1 files changed, 47 insertions, 24 deletions

diff --git a/doc/README.stats_tree b/doc/README.stats_tree
index 20bcc09c30..0a7e53da3d 100644
--- a/doc/README.stats_tree
+++ b/doc/README.stats_tree
@@ -63,14 +63,15 @@ static gchar* st_str_udp_term = "UDP terminations";
 /* this one initializes the tree, creating the root nodes */
 extern void udp_term_stats_tree_init(stats_tree* st) {
 	/* we create a node under which we'll add every termination */
-	st_udp_term = stats_tree_create_node(st, st_str_udp_term, 0, TRUE);
+	st_udp_term = stats_tree_create_node(st, st_str_udp_term, 0, STAT_DT_INT, TRUE);
 }
 
 /* this one will be called with every udp packet */
-extern int udp_term_stats_tree_packet(stats_tree *st, /* st as it was passed to us */
-                                      packet_info *pinfo,  /* we'll fetch the addresses from here */
-                                      epan_dissect_t *edt _U_, /* unused */
-                                      const void *p) /* we'll use this to fetch the ports */
+extern tap_packet_status
+udp_term_stats_tree_packet(stats_tree *st, /* st as it was passed to us */
+                           packet_info *pinfo,  /* we'll fetch the addresses from here */
+                           epan_dissect_t *edt _U_, /* unused */
+                           const void *p) /* we'll use this to fetch the ports */
 {
 	static guint8 str[128];
 	e_udphdr* udphdr = (e_udphdr*) p;
@@ -112,10 +113,13 @@ the stats_tree API
  data structure which should be passed to the api functions.
 
 stats_tree_register(tapname, abbr, name, flags, packet_cb, init_cb, cleanup_cb);
- registers a new stats tree
+ registers a new stats tree with default group REGISTER_STAT_GROUP_UNSORTED
 
 stats_tree_register_plugin(tapname, abbr, name, flags, packet_cb, init_cb, cleanup_cb);
- registers a new stats tree from a plugin
+ registers a new stats tree from a plugin with the default group
+
+stats_tree_register_with_group(tapname, abbr, name, flags, packet_cb, init_cb, cleanup_cb, stat_group);
+ registers a new stats tree under a particular stat group
 
 stats_tree_parent_id_by_name( st, parent_name)
   returns the id of a candidate parent node given its name
@@ -126,15 +130,17 @@ Node functions
 
 All the functions that operate on nodes return a parent_id
 
-stats_tree_create_node(st, name, parent_id, with_children)
+stats_tree_create_node(st, name, parent_id, datatype, with_children)
   Creates a node in the tree (to be used in the in init_cb)
     name: the name of the new node
     parent_id: the id of the parent_node (NULL for root)
+    datatype: datatype of the new node, STAT_DT_INT or STAT_DT_FLOAT. The only
+              methods implemented for floats are averages.
     with_children: TRUE if this node will have "dynamically created" children
                    (i.e. it will be a candidate parent)
 
 
-stats_tree_create_node_by_pname(st, name, parent_name, with_children);
+stats_tree_create_node_by_pname(st, name, parent_name, datatype, with_children);
   As before but creates a node using its parent's name
 
 
@@ -146,8 +152,8 @@ stats_tree_range_node_with_pname(st, name, parent_name, ...)
        stats_tree_create_range_node(st,name,parent_id,
 				"-99","100-199","200-299","300-399","400-", NULL);
 
-stats_tree_tick_range( st, name,  parent_id, value_in_range);
-stats_tree_tick_range_by_pname(st,name,parent_name,value_in_range)
+stats_tree_tick_range(st, name, parent_id, value_in_range);
+stats_tree_tick_range_by_pname(st, name, parent_name, value_in_range)
    Increases by one the ranged node and the sub node to whose range the value belongs
 
 
@@ -159,19 +165,18 @@ stats_tree_tick_pivot(st, pivot_id, pivoted_string);
  Each time a pivot node will be ticked it will get increased, and, it will
  increase (or create) the children named as pivoted_string
 
-
 the following will either increase or create a node (with value 1) when called
 
-tick_stat_node(st,name,parent_id,with_children)
+tick_stat_node(st, name, parent_id, with_children)
 increases by one a stat_node
 
-increase_stat_node(st,name,parent_id,with_children,value)
+increase_stat_node(st, name, parent_id, with_children, value)
 increases by value a stat_node
 
-set_stat_node(st,name,parent_id,with_children,value)
+set_stat_node(st, name, parent_id, with_children, value)
 sets the value of a stat_node
 
-zero_stat_node(st,name,parent_id,with_children)
+zero_stat_node(st, name, parent_id, with_children)
 resets to zero a stat_node
 
 Averages work by tracking both the number of items added to node (the ticking
@@ -179,8 +184,9 @@ action) and the value of each item added to the node. This is done
 automatically for ranged nodes; for other node types you need to call one of
 the functions below to associate item values with each tick.
 
-avg_stat_node_add_value_notick(st,name,parent_id,with_children,value)
-avg_stat_node_add_value(st,name,parent_id,with_children,value)
+avg_stat_node_add_value_notick(st, name, parent_id, with_children, value)
+avg_stat_node_add_value_int(st, name, parent_id, with_children, value)
+avg_stat_node_add_value_float(st, name, parent_id, with_children, value)
 
 The difference between the above functions is whether the item count is
 increased or not. To properly compute the average you need to either call
@@ -191,11 +197,14 @@ it does not understand the command. This would result in 0 counts for all
 nodes. It is preferred to use avg_stat_node_add_value if you are not writing
 a plug-in.
 
-avg_stat_node_add_value is used the same way as tick_stat_node with the
+avg_stat_node_add_value_int is used the same way as tick_stat_node with the
 exception that you now specify an additional value associated with the tick.
 
+avg_stat_node_add_value_float is used to compute averages of floats, for nodes
+with the STAT_DT_FLOAT datatype.
+
 Do not mix increase_stat_node, set_stat_node or zero_stat_node
-with avg_stat_node_add_value as this will lead to incorrect results for the
+with avg_stat_node_add_value_int as this will lead to incorrect results for the
 average value.
 
 stats_tree now also support setting flags per node to control the behaviour
@@ -204,11 +213,25 @@ stat_node_clear_flags functions. Currently these flags are defined:
 
 	ST_FLG_DEF_NOEXPAND: By default the top-level nodes in a tree are
 			automatically expanded in the GUI. Setting this flag on
-			such a node	prevents the node from automatically expanding.
+			such a node prevents the node from automatically
+			expanding.
 	ST_FLG_SORT_TOP: Nodes with this flag is sorted separately from nodes
-			without this flag (in effect partitioning tree into a top and
-			bottom half. Each half is sorted normally. Top always appear
-			first :)
+			without this flag (in effect partitioning tree into a top
+			and bottom half. Each half is sorted normally. Top always
+			appear first :)
+
+The same node manipulations can also be performed via generic functions:
+
+stats_tree_manip_node_int(mode, st, name, parent_id, with_children, value);
+stats_tree_manip_node_float(mode, st, name, parent_id, with_children, value);
+
+mode is an enum with the following set of values:
+    MN_INCREASE
+    MN_SET
+    MN_AVERAGE
+    MN_AVERAGE_NOTICK
+    MN_SET_FLAGS
+    MN_CLEAR_FLAGS
 
 You can find more examples of these in $srcdir/plugins/epan/stats_tree/pinfo_stats_tree.c