core: Rewrote ping-module, better performance and cleaner code.

1 files changed, 95 insertions, 0 deletions

diff --git a/core/ping.c b/core/ping.c
new file mode 100644
index 00000000..8a7d534f
--- /dev/null
+++ b/core/ping.c
@@ -0,0 +1,95 @@
+/*
+ * ping.c -- Buffered pinging using cyclic arrays.
+ *
+ * This file is donated to the Tox Project.
+ * Copyright 2013  plutooo
+ */
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "network.h"
+#include "util.h"
+
+#define PING_NUM_MAX 256
+#define PING_TIMEOUT 5 // 5s
+
+typedef struct {
+  IP_Port  ipp;
+  uint64_t id;
+  uint64_t timestamp;
+} pinged_t;
+
+static pinged_t pings[PING_NUM_MAX];
+static size_t   num_pings;
+static size_t   pos_pings;
+
+
+void init_ping() {
+  num_pings = 0;
+  pos_pings = 0;
+}
+
+static bool is_timeout(uint64_t time) {
+  return (time + PING_TIMEOUT) < now();
+}
+
+static void remove_timeouts() { // O(n)
+  size_t i, id;
+  size_t new_pos = pos_pings;
+  size_t new_num = num_pings;
+
+  // Loop through buffer, oldest first
+  for(i=0; i<num_pings; i++) {
+    id = (pos_pings + i) % PING_NUM_MAX;
+
+    if(is_timeout(pings[id].timestamp)) {
+      new_pos++;
+      new_num--;
+    }
+    // Break here because list is sorted.
+    else
+      break;
+  }
+
+  num_pings = new_num;
+  pos_pings = new_pos % PING_NUM_MAX;
+}
+
+uint64_t add_ping(IP_Port ipp) { // O(n)
+  size_t p;
+  
+  remove_timeouts();
+
+  // Remove oldest ping if full buffer
+  if(num_pings == PING_NUM_MAX) {
+    num_pings--;
+    pos_pings = (pos_pings + 1) % PING_NUM_MAX;
+  }
+
+  // Insert new ping at end of list
+  p = (pos_pings + num_pings) % PING_NUM_MAX;
+
+  pings[p].ipp       = ipp;
+  pings[p].timestamp = now();
+  pings[p].id        = random_64b();
+
+  num_pings++;
+  return pings[p].id;
+}
+
+bool is_pinging(IP_Port ipp, uint64_t ping_id) { // O(n)
+  size_t i, id;
+
+  remove_timeouts();
+
+  for(i=0; i<num_pings; i++) {
+    id = (pos_pings + i) % PING_NUM_MAX;
+
+    if(ipp_eq(pings[id].ipp, ipp) && pings[id].id == ping_id) {
+      return true;
+    }
+  }
+
+  return false;
+}