From 96c62bc4b82c7b660531fe58a187a74acb8ca714 Mon Sep 17 00:00:00 2001
From: Arvid Norberg <arvid@libtorrent.org>
Date: Thu, 28 Feb 2013 03:29:33 +0000
Subject: [PATCH] merged fix from RC_0_16

---
 ChangeLog             |  1 +
 src/file_storage.cpp  | 28 ++++++++++++++++++++++++----
 test/test_storage.cpp | 25 +++++++++++++++++++++++++
 3 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index b60b34214..ca90ad18d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -14,6 +14,7 @@
 	* fix uTP edge case where udp socket buffer fills up
 	* fix nagle implementation in uTP
 
+	* improve file_storage::map_file when dealing with invalid input
 	* improve handling of invalid utf-8 sequences in strings in torrent files
 	* handle more cases of broken .torrent files
 	* fix bug filename collision resolver
diff --git a/src/file_storage.cpp b/src/file_storage.cpp
index 64d325e74..711decd22 100644
--- a/src/file_storage.cpp
+++ b/src/file_storage.cpp
@@ -283,12 +283,32 @@ namespace libtorrent
 	{
 		TORRENT_ASSERT(file_index < num_files());
 		TORRENT_ASSERT(file_index >= 0);
-		size_type offset = file_offset + this->file_offset(file_index);
 
 		peer_request ret;
-		ret.piece = int(offset / piece_length());
-		ret.start = int(offset % piece_length());
-		ret.length = size;
+		if (file_index < 0 || file_index >= num_files())
+		{
+			ret.piece = m_num_pieces;
+			ret.start = 0;
+			ret.length = 0;
+			return ret;
+		}
+
+		size_type offset = file_offset + this->file_offset(file_index);
+
+		if (offset >= total_size())
+		{
+			ret.piece = m_num_pieces;
+			ret.start = 0;
+			ret.length = 0;
+		}
+		else
+		{
+			ret.piece = int(offset / piece_length());
+			ret.start = int(offset % piece_length());
+			ret.length = size;
+			if (offset + size > total_size())
+				ret.length = total_size() - offset;
+		}
 		return ret;
 	}
 
diff --git a/test/test_storage.cpp b/test/test_storage.cpp
index e45bea3cf..f66ee1d30 100644
--- a/test/test_storage.cpp
+++ b/test/test_storage.cpp
@@ -1075,6 +1075,31 @@ int test_main()
 	std::for_each(test_paths.begin(), test_paths.end(), boost::bind(&run_test, _1, true));
 	std::for_each(test_paths.begin(), test_paths.end(), boost::bind(&run_test, _1, false));
 
+	file_storage fs;
+	fs.set_piece_length(512);
+	fs.add_file("temp_storage/test1.tmp", 17);
+	fs.add_file("temp_storage/test2.tmp", 612);
+	fs.add_file("temp_storage/test3.tmp", 0);
+	fs.add_file("temp_storage/test4.tmp", 0);
+	fs.add_file("temp_storage/test5.tmp", 3253);
+	// size: 3882
+	fs.add_file("temp_storage/test6.tmp", 841);
+	// size: 4723
+
+	peer_request rq = fs.map_file(0, 0, 10);
+	TEST_EQUAL(rq.piece, 0);
+	TEST_EQUAL(rq.start, 0);
+	TEST_EQUAL(rq.length, 10);
+	rq = fs.map_file(5, 0, 10);
+	TEST_EQUAL(rq.piece, 7);
+	TEST_EQUAL(rq.start, 298);
+	TEST_EQUAL(rq.length, 10);
+	rq = fs.map_file(5, 0, 1000);
+	TEST_EQUAL(rq.piece, 7);
+	TEST_EQUAL(rq.start, 298);
+	TEST_EQUAL(rq.length, 841);
+
+
 	return 0;
 }