1 files changed, 117 insertions, 0 deletions
diff --git a/Src/replicant/nu/ProgressTracker.cpp b/Src/replicant/nu/ProgressTracker.cpp
new file mode 100644
index 00000000..e42cada3
--- /dev/null
+++ b/Src/replicant/nu/ProgressTracker.cpp
@@ -0,0 +1,117 @@
+#include "ProgressTracker.h"
+#include <stdio.h>
+/* Helper class for managing valid chunks in non-sequential scenarios 
+e.g. progressive downloading */
+
+ProgressTracker::ProgressTracker()
+{
+	current_position=0;
+	current_chunk=0;
+	chunks[0]=0;
+	chunks[null_position]=null_position;
+};
+
+void ProgressTracker::Write(uint64_t bytes_written)
+{
+	nu::AutoLock list_lock(list_guard);
+	ChunkList::iterator next, itr = chunks.find(current_chunk);
+	current_position += bytes_written;
+	if (itr->second < current_position)
+		itr->second = current_position;
+
+	for (;;)
+	{
+		next = itr;
+		next++;
+		if (next != chunks.end() && (next->first <= itr->second))
+		{
+			itr->second = next->second;
+			chunks.erase(next);
+		}
+		else
+			break;
+	}
+}
+
+bool ProgressTracker::Valid(uint64_t requested_position, uint64_t requested_end, uint64_t *available) 
+{
+	nu::AutoLock list_lock(list_guard);
+	for (ChunkList::iterator itr=chunks.begin();itr!=chunks.end();itr++)
+	{
+		if (requested_position >= itr->first)
+		{
+			if (requested_position < itr->second)
+			{
+				if (available)
+					*available = itr->second - requested_position;
+
+				if (requested_end <= itr->second)
+					return true;
+				else
+					return false;
+
+			}
+		}
+	}
+	if (available)
+		*available = 0;
+	return false;
+}
+
+bool ProgressTracker::Seek(uint64_t requested_position, uint64_t requested_end, uint64_t *new_start, uint64_t *new_end)
+{
+	nu::AutoLock list_lock(list_guard);
+	uint64_t last_good_start=0;
+	ChunkList::iterator itr;
+	for (itr=chunks.begin();itr!=chunks.end();itr++)
+	{
+		if (requested_position >= itr->first)
+		{
+			current_chunk = itr->first;
+			if (requested_position <= itr->second)
+			{
+				ChunkList::iterator next = itr;
+				next++;
+				*new_end = next->first;
+
+				*new_start = current_position = itr->second;
+
+				if (requested_end <= itr->second)
+				{
+					return true;
+				}
+				else
+				{
+					return false;
+				}
+			}
+			else
+			{
+				last_good_start = itr->second;
+			}
+		}
+	}
+	if (last_good_start > requested_position)
+		*new_start = current_position = last_good_start;
+	else
+	{
+
+		*new_start = current_chunk = current_position = requested_position;
+		chunks[current_chunk] = current_chunk;
+	}
+	*new_end = null_position;
+	return false;
+}
+
+void ProgressTracker::Dump()
+{
+	ChunkList::iterator itr;
+	for (itr=chunks.begin();itr!=chunks.end();itr++)
+	{
+		printf("%llu - %llu\n", itr->first, itr->second);
+	}
+
+}
+
+
+const uint64_t ProgressTracker::null_position = (uint64_t)-1;