bittorrent::computeFastSet: Return std::vector

src/DefaultBtInteractive.cc

@@ -229,11 +229,11 @@ void DefaultBtInteractive::addBitfieldMessageToQueue() {
 
 void DefaultBtInteractive::addAllowedFastMessageToQueue() {
   if(peer_->isFastExtensionEnabled()) {
-    std::vector<size_t> fastSet;
-    bittorrent::computeFastSet(fastSet, peer_->getIPAddress(),
-                               downloadContext_->getNumPieces(),
-                               bittorrent::getInfoHash(downloadContext_),
-                               allowedFastSetSize_);
+    auto fastSet =
+      bittorrent::computeFastSet(peer_->getIPAddress(),
+                                 downloadContext_->getNumPieces(),
+                                 bittorrent::getInfoHash(downloadContext_),
+                                 allowedFastSetSize_);
     for(std::vector<size_t>::const_iterator itr = fastSet.begin(),
           eoi = fastSet.end(); itr != eoi; ++itr) {
       dispatcher_->addMessageToQueue

src/bittorrent_helper.cc

@@ -658,14 +658,15 @@ getInfoHashString(DownloadContext* dctx)
   return util::toHex(getTorrentAttrs(dctx)->infoHash);
 }
 
-void computeFastSet
-(std::vector<size_t>& fastSet, const std::string& ipaddr,
+std::vector<size_t> computeFastSet
+(const std::string& ipaddr,
  size_t numPieces, const unsigned char* infoHash, size_t fastSetSize)
 {
+  std::vector<size_t> fastSet;
   unsigned char compact[COMPACT_LEN_IPV6];
   int compactlen = packcompact(compact, ipaddr, 0);
   if(compactlen != COMPACT_LEN_IPV4) {
-    return;
+    return fastSet;
   }
   if(numPieces < fastSetSize) {
     fastSetSize = numPieces;
@@ -689,7 +690,9 @@ void computeFastSet
       memcpy(&ny, x+j, 4);
       uint32_t y = ntohl(ny);
       size_t index = y%numPieces;
-      if(std::find(fastSet.begin(), fastSet.end(), index) == fastSet.end()) {
+      if(std::find(std::begin(fastSet), std::end(fastSet), index) ==
+         std::end(fastSet)) {
+
         fastSet.push_back(index);
       }
     }
@@ -698,6 +701,8 @@ void computeFastSet
     message_digest::digest(temp, sizeof(temp), sha1.get(), x, sizeof(x));
     memcpy(x, temp, sizeof(x));
   }
+
+  return fastSet;
 }
 
 std::string generatePeerId(const std::string& peerIdPrefix)

src/bittorrent_helper.h

@@ -144,9 +144,9 @@ const unsigned char* getStaticPeerId();
 // length.
 void setStaticPeerId(const std::string& newPeerId);
 
-// Computes fast set index and stores them in fastset.
-void computeFastSet
-(std::vector<size_t>& fastSet, const std::string& ipaddr,
+// Computes fast set index and returns them.
+std::vector<size_t> computeFastSet
+(const std::string& ipaddr,
  size_t numPieces, const unsigned char* infoHash, size_t fastSetSize);
 
 // Make sure that don't recieve return value into std::shared_ptr.

test/BittorrentHelperTest.cc

@@ -321,23 +321,20 @@ void BittorrentHelperTest::testComputeFastSet()
   int fastSetSize = 10;
   size_t numPieces = 1000;
   {
-    std::vector<size_t> fastSet;
-    computeFastSet(fastSet, ipaddr, numPieces, infoHash, fastSetSize);
+    auto fastSet = computeFastSet(ipaddr, numPieces, infoHash, fastSetSize);
     size_t ans[] = { 686, 459, 278, 200, 404, 834, 64, 203, 760, 950 };
     CPPUNIT_ASSERT(std::equal(fastSet.begin(), fastSet.end(), std::begin(ans)));
   }
   ipaddr = "10.0.0.1";
   {
-    std::vector<size_t> fastSet;
-    computeFastSet(fastSet, ipaddr, numPieces, infoHash, fastSetSize);
+    auto fastSet = computeFastSet(ipaddr, numPieces, infoHash, fastSetSize);
     size_t ans[] = { 568, 188, 466, 452, 550, 662, 109, 226, 398, 11 };
     CPPUNIT_ASSERT(std::equal(fastSet.begin(), fastSet.end(), std::begin(ans)));
   }
   // See when pieces < fastSetSize
   numPieces = 9;
   {
-    std::vector<size_t> fastSet;
-    computeFastSet(fastSet, ipaddr, numPieces, infoHash, fastSetSize);
+    auto fastSet = computeFastSet(ipaddr, numPieces, infoHash, fastSetSize);
     size_t ans[] = { 8, 6, 7, 5, 1, 4, 0, 2, 3 };
     CPPUNIT_ASSERT(std::equal(fastSet.begin(), fastSet.end(), std::begin(ans)));
   }