merged merkle torrent creation fix from RC_0_16

ChangeLog

@@ -10,6 +10,7 @@
 	* fix uTP edge case where udp socket buffer fills up
 	* fix nagle implementation in uTP
 
+	* fixed merkle tree torrent creation bug
 	* fixed crash with empty url-lists in torrent files
 	* added missing max_connections() function to python bindings
 

examples/make_torrent.cpp

@@ -255,8 +255,14 @@ int main(int argc, char* argv[])
 		if (!merklefile.empty())
 		{
 			output = fopen(merklefile.c_str(), "wb+");
+			if (output == NULL)
+			{
+				fprintf(stderr, "failed to open file \"%s\": (%d) %s\n"
+					, merklefile.c_str(), errno, strerror(errno));
+				return 1;
+			}
 			int ret = fwrite(&t.merkle_tree()[0], 20, t.merkle_tree().size(), output);
-			if (ret != t.merkle_tree().size() * 20)
+			if (ret != t.merkle_tree().size())
 			{
 				fprintf(stderr, "failed to write %s: (%d) %s\n"
 					, merklefile.c_str(), errno, strerror(errno));

include/libtorrent/torrent_info.hpp

@@ -74,6 +74,11 @@ namespace libtorrent
 		, tracker_retry_delay_max = 60 * 60
 	};
 
+	TORRENT_EXTRA_EXPORT int merkle_num_leafs(int);
+	TORRENT_EXTRA_EXPORT int merkle_num_nodes(int);
+	TORRENT_EXTRA_EXPORT int merkle_get_parent(int);
+	TORRENT_EXTRA_EXPORT int merkle_get_sibling(int);
+
 	struct TORRENT_EXPORT announce_entry
 	{
 		announce_entry(std::string const& u);

src/create_torrent.cpp

@@ -34,6 +34,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/file_pool.hpp"
 #include "libtorrent/storage.hpp"
 #include "libtorrent/escape_string.hpp"
+#include "libtorrent/torrent_info.hpp" // for merkle_*()
 
 #include <boost/bind.hpp>
 #include <boost/next_prior.hpp>
@@ -45,11 +46,6 @@ POSSIBILITY OF SUCH DAMAGE.
 
 namespace libtorrent
 {
-	// defined in torrent_info.cpp
-	int merkle_num_leafs(int);
-	int merkle_num_nodes(int);
-	int merkle_get_parent(int);
-	int merkle_get_sibling(int);
 
 	namespace detail
 	{

src/torrent_info.cpp

@@ -421,10 +421,11 @@ namespace libtorrent
 
 	int merkle_num_leafs(int pieces)
 	{
+		TORRENT_ASSERT(pieces > 0);
 		// round up to nearest 2 exponent
-		int i;
+		int ret = 1;
-		for (i = 0; pieces > 0; pieces >>= 1, ++i);
+		while (pieces > ret) ret <<= 1;
-		return 1 << i;
+		return ret;
 	}
 
 	int load_file(std::string const& filename, std::vector<char>& v, error_code& ec, int limit)

test/test_primitives.cpp

@@ -1913,6 +1913,74 @@ int test_main()
 
 	test1.resize(100, true);
 	TEST_CHECK(test1.all_set() == true);
+
+	// test merkle_*() functions
+
+	// this is the structure:
+	//             0
+	//      1              2
+	//   3      4       5       6
+	//  7 8    9 10   11 12   13 14
+	// num_leafs = 8
+
+	TEST_EQUAL(merkle_num_leafs(1), 1);
+	TEST_EQUAL(merkle_num_leafs(2), 2);
+	TEST_EQUAL(merkle_num_leafs(3), 4);
+	TEST_EQUAL(merkle_num_leafs(4), 4);
+	TEST_EQUAL(merkle_num_leafs(5), 8);
+	TEST_EQUAL(merkle_num_leafs(6), 8);
+	TEST_EQUAL(merkle_num_leafs(7), 8);
+	TEST_EQUAL(merkle_num_leafs(8), 8);
+	TEST_EQUAL(merkle_num_leafs(9), 16);
+	TEST_EQUAL(merkle_num_leafs(10), 16);
+	TEST_EQUAL(merkle_num_leafs(11), 16);
+	TEST_EQUAL(merkle_num_leafs(12), 16);
+	TEST_EQUAL(merkle_num_leafs(13), 16);
+	TEST_EQUAL(merkle_num_leafs(14), 16);
+	TEST_EQUAL(merkle_num_leafs(15), 16);
+	TEST_EQUAL(merkle_num_leafs(16), 16);
+	TEST_EQUAL(merkle_num_leafs(17), 32);
+	TEST_EQUAL(merkle_num_leafs(18), 32);
+
+	// parents
+	TEST_EQUAL(merkle_get_parent(1), 0);
+	TEST_EQUAL(merkle_get_parent(2), 0);
+	TEST_EQUAL(merkle_get_parent(3), 1);
+	TEST_EQUAL(merkle_get_parent(4), 1);
+	TEST_EQUAL(merkle_get_parent(5), 2);
+	TEST_EQUAL(merkle_get_parent(6), 2);
+	TEST_EQUAL(merkle_get_parent(7), 3);
+	TEST_EQUAL(merkle_get_parent(8), 3);
+	TEST_EQUAL(merkle_get_parent(9), 4);
+	TEST_EQUAL(merkle_get_parent(10), 4);
+	TEST_EQUAL(merkle_get_parent(11), 5);
+	TEST_EQUAL(merkle_get_parent(12), 5);
+	TEST_EQUAL(merkle_get_parent(13), 6);
+	TEST_EQUAL(merkle_get_parent(14), 6);
+
+	// siblings
+	TEST_EQUAL(merkle_get_sibling(1), 2);
+	TEST_EQUAL(merkle_get_sibling(2), 1);
+	TEST_EQUAL(merkle_get_sibling(3), 4);
+	TEST_EQUAL(merkle_get_sibling(4), 3);
+	TEST_EQUAL(merkle_get_sibling(5), 6);
+	TEST_EQUAL(merkle_get_sibling(6), 5);
+	TEST_EQUAL(merkle_get_sibling(7), 8);
+	TEST_EQUAL(merkle_get_sibling(8), 7);
+	TEST_EQUAL(merkle_get_sibling(9), 10);
+	TEST_EQUAL(merkle_get_sibling(10), 9);
+	TEST_EQUAL(merkle_get_sibling(11), 12);
+	TEST_EQUAL(merkle_get_sibling(12), 11);
+	TEST_EQUAL(merkle_get_sibling(13), 14);
+	TEST_EQUAL(merkle_get_sibling(14), 13);
+
+	// total number of nodes given the number of leafs
+	TEST_EQUAL(merkle_num_nodes(1), 1);
+	TEST_EQUAL(merkle_num_nodes(2), 3);
+	TEST_EQUAL(merkle_num_nodes(4), 7);
+	TEST_EQUAL(merkle_num_nodes(8), 15);
+	TEST_EQUAL(merkle_num_nodes(16), 31);
+
 	return 0;
 }