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deltas: switch cache to unordered_set and manage size & lifecycle.

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We should have a larger delta-cache with more users eg.

Change-Id: Idc3075636df2e7705950fcf6762e40546792a285
Signed-off-by: Michael Meeks <michael.meeks@collabora.com>
This commit is contained in:
Michael Meeks 2022-06-15 17:14:48 +01:00
parent 123f9b5c41
commit 935715309a
1 changed files with 41 additions and 13 deletions
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54
kit/Delta.hpp
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@ -8,6 +8,7 @@
#pragma once
#include <vector>
#include <unordered_set>
#include <assert.h>
#include <zlib.h>
#include <Log.hpp>
@ -196,8 +197,43 @@ class DeltaGenerator {
DeltaBitmapRow *_rows;
};
struct DeltaHasher {
std::size_t operator()(const std::shared_ptr<DeltaData> &t) const
{
return (t->_left << 20) ^ t->_top ^ (t->_part << 15) ^ (t->_size << 7);
}
};
struct DeltaCompare {
bool operator()(const std::shared_ptr<DeltaData> &a,
const std::shared_ptr<DeltaData> &b) const
{
return a->_left == b->_left && a->_top == b->_top &&
a->_size == b->_size && a->_part == b->_part;
}
};
/// The last several bitmap entries as a cache
std::vector<std::shared_ptr<DeltaData>> _deltaEntries;
std::unordered_set<std::shared_ptr<DeltaData>, DeltaHasher, DeltaCompare> _deltaEntries;
size_t _maxEntries;
void rebalanceDeltasT()
{
if (_deltaEntries.size() > _maxEntries)
{
size_t toRemove = _deltaEntries.size() - (_maxEntries * 3 / 4);
std::vector<std::shared_ptr<DeltaData>> entries;
entries.insert(entries.end(), _deltaEntries.begin(), _deltaEntries.end());
std::sort(entries.begin(), entries.end(),
[](const std::shared_ptr<DeltaData> &a,
const std::shared_ptr<DeltaData> &b)
{
return a->getWid() < b->getWid();
});
for (size_t i = 0; i < toRemove; ++i)
_deltaEntries.erase(entries[i]);
}
}
// Unpremultiplies data and converts native endian ARGB => RGBA bytes
static void
@ -441,21 +477,13 @@ class DeltaGenerator {
if (_deltaEntries.size() > 16) // FIXME: hard-coded & not per-view
_deltaEntries.erase(_deltaEntries.begin());
for (auto &old : _deltaEntries)
auto it = _deltaEntries.find(update);
if (it == _deltaEntries.end())
{
if (old->_left == tileLeft && old->_top == tileTop &&
old->_size == tileSize && old->_part == tilePart)
{
cacheEntry = old;
break;
}
}
if (!cacheEntry)
{
_deltaEntries.push_back(update);
_deltaEntries.insert(update);
return false;
}
cacheEntry = *it;
cacheEntry->use();
}