From e84275e42927a333ea274c2c07612b68e4d8682a Mon Sep 17 00:00:00 2001
From: Mukund Sivaraman <muks@mukund.org>
Date: Wed, 20 Aug 2008 14:36:15 +0000
Subject: [PATCH] Replace the random number generator inside peer-mgr with a
 stupid faster one.

---
 libtransmission/peer-mgr.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/libtransmission/peer-mgr.c b/libtransmission/peer-mgr.c
index 9355db7f8..0ecd3fe62 100644
--- a/libtransmission/peer-mgr.c
+++ b/libtransmission/peer-mgr.c
@@ -130,6 +130,27 @@ struct tr_peerMgr
 ***
 **/
 
+/* The following is not a very high quality random number generator.  It
+ * is mainly used as a simple stupid random number generator inside some
+ * functions below. Please don't use it for anything else unless you
+ * know what you're doing. Use tr_cryptoRandInt() instead.
+ */
+
+static int
+tr_simpleRandInt( int sup )
+{
+    static int init = 0;
+    assert( sup > 0 );
+
+    if ( !init )
+    {
+        srand( tr_date() );
+        init = 1;
+    }
+
+    return rand() % sup;
+}
+
 static void
 managerLock( const struct tr_peerMgr * manager )
 {
@@ -600,7 +621,7 @@ getPreferredPieces( Torrent     * t,
             setme->piece = piece;
             setme->priority = inf->pieces[piece].priority;
             setme->peerCount = 0;
-            setme->random = tr_cryptoRandInt( UINT16_MAX );
+            setme->random = tr_simpleRandInt( UINT16_MAX );
             setme->missingBlockCount = tr_cpMissingBlocksInPiece( tor->completion, piece );
 
             for( k=0; k<peerCount; ++k ) {
@@ -642,7 +663,7 @@ getPeersUploadingToClient( Torrent * t, int * setmeCount )
      * get a chance at the first blocks in the queue */
     if( retCount ) {
         tr_peer ** tmp = tr_new( tr_peer*, retCount );
-        i = tr_cryptoRandInt( retCount );
+        i = tr_simpleRandInt( retCount );
         memcpy( tmp, ret, sizeof(tr_peer*) * retCount );
         memcpy( ret, tmp+i, sizeof(tr_peer*) * (retCount-i) );
         memcpy( ret+(retCount-i), tmp, sizeof(tr_peer*) * i );
@@ -1630,7 +1651,7 @@ rechoke( Torrent * t )
 
         if(( n = tr_ptrArraySize( randPool )))
         {
-            c = tr_ptrArrayNth( randPool, tr_cryptoRandInt( n ));
+            c = tr_ptrArrayNth( randPool, tr_simpleRandInt( n ));
             c->doUnchoke = 1;
             t->optimistic = c->peer;
         }
-- 
2.40.0