timediff: return timediff_t from the time diff functions

... to cater for systems with unsigned time_t variables.

- Renamed the functions to curlx_timediff and Curl_timediff_us.

- Added overflow protection for both of them in either direction for
  both 32 bit and 64 bit time_ts

- Reprefixed the curlx_time functions to use Curl_*

Reported-by: Peter Piekarski
Fixes #2004
Closes #2005

1 files changed, 7 insertions, 7 deletions

diff --git a/lib/url.c b/lib/url.c
index 76c09c72a..594160898 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -3459,8 +3459,8 @@ Curl_oldest_idle_connection(struct Curl_easy *data)
   struct curl_hash_iterator iter;
   struct curl_llist_element *curr;
   struct curl_hash_element *he;
-  time_t highscore =- 1;
-  time_t score;
+  timediff_t highscore =- 1;
+  timediff_t score;
   struct curltime now;
   struct connectdata *conn_candidate = NULL;
   struct connectbundle *bundle;
@@ -3481,7 +3481,7 @@ Curl_oldest_idle_connection(struct Curl_easy *data)
 
       if(!conn->inuse) {
         /* Set higher score for the age passed since the connection was used */
-        score = Curl_tvdiff(now, conn->now);
+        score = Curl_timediff(now, conn->now);
 
         if(score > highscore) {
           highscore = score;
@@ -3522,8 +3522,8 @@ find_oldest_idle_connection_in_bundle(struct Curl_easy *data,
                                       struct connectbundle *bundle)
 {
   struct curl_llist_element *curr;
-  time_t highscore = -1;
-  time_t score;
+  timediff_t highscore = -1;
+  timediff_t score;
   struct curltime now;
   struct connectdata *conn_candidate = NULL;
   struct connectdata *conn;
@@ -3538,7 +3538,7 @@ find_oldest_idle_connection_in_bundle(struct Curl_easy *data,
 
     if(!conn->inuse) {
       /* Set higher score for the age passed since the connection was used */
-      score = Curl_tvdiff(now, conn->now);
+      score = Curl_timediff(now, conn->now);
 
       if(score > highscore) {
         highscore = score;
@@ -3613,7 +3613,7 @@ static int call_disconnect_if_dead(struct connectdata *conn,
 static void prune_dead_connections(struct Curl_easy *data)
 {
   struct curltime now = Curl_tvnow();
-  time_t elapsed = Curl_tvdiff(now, data->state.conn_cache->last_cleanup);
+  time_t elapsed = Curl_timediff(now, data->state.conn_cache->last_cleanup);
 
   if(elapsed >= 1000L) {
     Curl_conncache_foreach(data->state.conn_cache, data,