118 lines
2.4 KiB
C++
118 lines
2.4 KiB
C++
#include "ProgressTracker.h"
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#include <stdio.h>
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/* Helper class for managing valid chunks in non-sequential scenarios
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e.g. progressive downloading */
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ProgressTracker::ProgressTracker()
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{
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current_position=0;
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current_chunk=0;
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chunks[0]=0;
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chunks[null_position]=null_position;
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};
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void ProgressTracker::Write(uint64_t bytes_written)
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{
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nu::AutoLock list_lock(list_guard);
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ChunkList::iterator next, itr = chunks.find(current_chunk);
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current_position += bytes_written;
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if (itr->second < current_position)
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itr->second = current_position;
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for (;;)
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{
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next = itr;
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next++;
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if (next != chunks.end() && (next->first <= itr->second))
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{
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itr->second = next->second;
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chunks.erase(next);
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}
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else
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break;
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}
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}
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bool ProgressTracker::Valid(uint64_t requested_position, uint64_t requested_end, uint64_t *available)
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{
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nu::AutoLock list_lock(list_guard);
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for (ChunkList::iterator itr=chunks.begin();itr!=chunks.end();itr++)
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{
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if (requested_position >= itr->first)
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{
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if (requested_position < itr->second)
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{
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if (available)
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*available = itr->second - requested_position;
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if (requested_end <= itr->second)
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return true;
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else
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return false;
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}
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}
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}
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if (available)
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*available = 0;
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return false;
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}
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bool ProgressTracker::Seek(uint64_t requested_position, uint64_t requested_end, uint64_t *new_start, uint64_t *new_end)
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{
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nu::AutoLock list_lock(list_guard);
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uint64_t last_good_start=0;
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ChunkList::iterator itr;
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for (itr=chunks.begin();itr!=chunks.end();itr++)
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{
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if (requested_position >= itr->first)
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{
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current_chunk = itr->first;
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if (requested_position <= itr->second)
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{
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ChunkList::iterator next = itr;
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next++;
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*new_end = next->first;
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*new_start = current_position = itr->second;
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if (requested_end <= itr->second)
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{
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return true;
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}
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else
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{
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return false;
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}
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}
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else
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{
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last_good_start = itr->second;
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}
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}
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}
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if (last_good_start > requested_position)
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*new_start = current_position = last_good_start;
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else
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{
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*new_start = current_chunk = current_position = requested_position;
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chunks[current_chunk] = current_chunk;
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}
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*new_end = null_position;
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return false;
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}
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void ProgressTracker::Dump()
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{
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ChunkList::iterator itr;
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for (itr=chunks.begin();itr!=chunks.end();itr++)
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{
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printf("%llu - %llu\n", itr->first, itr->second);
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}
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}
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const uint64_t ProgressTracker::null_position = (uint64_t)-1;
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