Aegisub/aegisub/libmedia/cache/video_cache.cpp
2011-02-06 19:28:17 +00:00

129 lines
3.5 KiB
C++

// Copyright (c) 2008, Rodrigo Braz Monteiro
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// * Neither the name of the Aegisub Group nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// Aegisub Project http://www.aegisub.org/
//
// $Id$
/// @file video_provider_cache.cpp
/// @brief Aggregate video provider caching previously requested frames
/// @ingroup video_input
///
#include "config.h"
//#include "main.h"
#include "video_cache.h"
namespace media {
/// DOCME
/// @class CachedFrame
/// @brief DOCME
///
/// DOCME
struct CachedFrame {
/// DOCME
AegiVideoFrame frame;
/// DOCME
int n;
};
/// @brief Constructor
/// @param parent
///
VideoProviderCache::VideoProviderCache(VideoProvider *parent)
: master(parent)
//XXX: , cacheMax(OPT_GET("Provider/Video/Cache/Size")->GetInt() << 20) // convert MB to bytes
{
}
/// @brief Destructor
///
VideoProviderCache::~VideoProviderCache() {
while (cache.size()) {
cache.front().frame.Clear();
cache.pop_front();
}
}
/// @brief Get frame
/// @param n
/// @return
///
const AegiVideoFrame VideoProviderCache::GetFrame(int n) {
// See if frame is cached
CachedFrame cached;
for (std::list<CachedFrame>::iterator cur=cache.begin();cur!=cache.end();cur++) {
cached = *cur;
if (cached.n == n) {
cache.erase(cur);
cache.push_back(cached);
return cached.frame;
}
}
// Not cached, retrieve it
const AegiVideoFrame frame = master->GetFrame(n);
const AegiVideoFrame *srcFrame = &frame;
// Cache frame
Cache(n,*srcFrame);
return *srcFrame;
}
/// @brief Add to cache
/// @param n
/// @param frame
void VideoProviderCache::Cache(int n,const AegiVideoFrame frame) {
// Cache full, use frame at front
if (GetCurCacheSize() >= cacheMax) {
cache.push_back(cache.front());
cache.pop_front();
}
// Cache not full, insert new one
else {
cache.push_back(CachedFrame());
}
// Cache
cache.back().n = n;
cache.back().frame.CopyFrom(frame);
}
/// @brief Get the current size of the cache
/// @return Returns the size in bytes
unsigned VideoProviderCache::GetCurCacheSize() {
int sz = 0;
for (std::list<CachedFrame>::iterator i = cache.begin(); i != cache.end(); i++)
sz += i->frame.memSize;
return sz;
}
} // namespace media