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#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;
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