/
synchronizelists_p.h
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/****************************************************************************************
**
** Copyright (C) 2014 Jolla Ltd.
** Contact: Andrew den Exter <andrew.den.exter@jolla.com>
** All rights reserved.
**
** This file is part of Nemo Transfer Engine package.
**
** You may use this file under the terms of the GNU Lesser General
** Public License version 2.1 as published by the Free Software Foundation
** and appearing in the file license.lgpl included in the packaging
** of this file.
**
** This library is free software; you can redistribute it and/or
** modify it under the terms of the GNU Lesser General Public
** License version 2.1 as published by the Free Software Foundation
** and appearing in the file license.lgpl included in the packaging
** of this file.
**
** This library is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
** Lesser General Public License for more details.
**
****************************************************************************************/
#ifndef SYNCHRONIZELISTS_P_H
#define SYNCHRONIZELISTS_P_H
template <typename T>
bool compareIdentity(const T &item, const T &reference)
{
return item == reference;
}
template <typename Agent, typename ReferenceList>
int insertRange(Agent *agent, int index, int count, const ReferenceList &source, int sourceIndex)
{
agent->insertRange(index, count, source, sourceIndex);
return count;
}
template <typename Agent>
int removeRange(Agent *agent, int index, int count)
{
agent->removeRange(index, count);
return 0;
}
template <typename Agent, typename ReferenceList>
int updateRange(Agent *agent, int index, int count, const ReferenceList &source, int sourceIndex)
{
agent->updateRange(index, count, source, sourceIndex);
return count;
}
template <typename Agent, typename CacheList, typename ReferenceList>
class SynchronizeList
{
public:
SynchronizeList(
Agent *agent,
const CacheList &cache,
int &c,
const ReferenceList &reference,
int &r)
: agent(agent), cache(cache), c(c), reference(reference), r(r)
{
int lastEqualC = c;
int lastEqualR = r;
for (; c < cache.count() && r < reference.count(); ++c, ++r) {
if (compareIdentity(cache.at(c), reference.at(r))) {
continue;
}
if (c > lastEqualC) {
lastEqualC += updateRange(agent, lastEqualC, c - lastEqualC, reference, lastEqualR);
c = lastEqualC;
lastEqualR = r;
}
bool match = false;
// Iterate through both the reference and cache lists in parallel looking for first
// point of commonality, when that is found resolve the differences and continue
// looking.
int count = 1;
for (; !match && c + count < cache.count() && r + count < reference.count(); ++count) {
typename CacheList::const_reference cacheItem = cache.at(c + count);
typename ReferenceList::const_reference referenceItem = reference.at(r + count);
for (int i = 0; i <= count; ++i) {
if (cacheMatch(i, count, referenceItem) || referenceMatch(i, count, cacheItem)) {
match = true;
break;
}
}
}
// Continue scanning the reference list if the cache has been exhausted.
for (int re = r + count; !match && re < reference.count(); ++re) {
typename ReferenceList::const_reference referenceItem = reference.at(re);
for (int i = 0; i < count; ++i) {
if (cacheMatch(i, re - r, referenceItem)) {
match = true;
break;
}
}
}
// Continue scanning the cache if the reference list has been exhausted.
for (int ce = c + count; !match && ce < cache.count(); ++ce) {
typename CacheList::const_reference cacheItem = cache.at(ce);
for (int i = 0; i < count; ++i) {
if (referenceMatch(i, ce - c, cacheItem)) {
match = true;
break;
}
}
}
if (!match)
return;
lastEqualC = c;
lastEqualR = r;
}
if (c > lastEqualC) {
updateRange(agent, lastEqualC, c - lastEqualC, reference, lastEqualR);
}
}
private:
// Tests if the cached id at i matches a referenceId.
// If there is a match removes all items traversed in the cache since the previous match
// and inserts any items in the reference set found to to not be in the cache.
bool cacheMatch(int i, int count, typename ReferenceList::const_reference referenceItem)
{
if (compareIdentity(cache.at(c + i), referenceItem)) {
if (i > 0)
c += removeRange(agent, c, i);
c += insertRange(agent, c, count, reference, r);
r += count;
return true;
} else {
return false;
}
}
// Tests if the referenceid at i matches a cacheId.
// If there is a match inserts all items traversed in the reference set since the
// previous match and removes any items from the cache that were not found in the
// reference list.
bool referenceMatch(int i, int count, typename ReferenceList::const_reference cacheItem)
{
if (compareIdentity(reference.at(r + i), cacheItem)) {
c += removeRange(agent, c, count);
if (i > 0)
c += insertRange(agent, c, i, reference, r);
r += i;
return true;
} else {
return false;
}
}
Agent * const agent;
const CacheList &cache;
int &c;
const ReferenceList &reference;
int &r;
};
template <typename Agent, typename CacheList, typename ReferenceList>
void completeSynchronizeList(
Agent *agent,
const CacheList &cache,
int &cacheIndex,
const ReferenceList &reference,
int &referenceIndex)
{
if (cacheIndex < cache.count()) {
agent->removeRange(cacheIndex, cache.count() - cacheIndex);
}
if (referenceIndex < reference.count()) {
agent->insertRange(cache.count(), reference.count() - referenceIndex, reference, referenceIndex);
}
cacheIndex = 0;
referenceIndex = 0;
}
template <typename Agent, typename CacheList, typename ReferenceList>
void synchronizeList(
Agent *agent,
const CacheList &cache,
int &cacheIndex,
const ReferenceList &reference,
int &referenceIndex)
{
SynchronizeList<Agent, CacheList, ReferenceList>(
agent, cache, cacheIndex, reference, referenceIndex);
}
template <typename Agent, typename CacheList, typename ReferenceList>
void synchronizeList(Agent *agent, const CacheList &cache, const ReferenceList &reference)
{
int cacheIndex = 0;
int referenceIndex = 0;
SynchronizeList<Agent, CacheList, ReferenceList>(
agent, cache, cacheIndex, reference, referenceIndex);
completeSynchronizeList(agent, cache, cacheIndex, reference, referenceIndex);
}
#endif