importer.h

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#ifndef MF_IMPORTER_FILTER_H_
#define MF_IMPORTER_FILTER_H_

#include <utility>
#include "filter.h"
#include "../io/frame_importer.h"
#include "../io/seekable_frame_importer.h"

namespace mf { namespace flow {

template<typename Importer, typename = void>
class importer_filter : public source_filter {
    static_assert(! Importer::is_seekable, "Importer must not be seekable");

private:
    Importer importer_;

public:
    output_type<Importer::dimension, typename Importer::elem_type> output;
    
    template<typename... Args>
    explicit importer_filter(filter_node& nd, Args&&... args) :
        source_filter(nd, false),
        importer_(std::forward<Args>(args)...),
        output(*this) { }
    
    void setup() override {
        output.define_frame_shape(importer_.frame_shape());
    }
    
    void process(node_job& job) override {
        auto out = job.out(output);
        return importer_.read_frame(out);
        if(importer_.reached_end()) job.mark_end();
    }
};


template<typename Importer>
class importer_filter<Importer, std::enable_if_t<Importer::is_seekable>> : public source_filter {
    static_assert(Importer::is_seekable, "Importer must be seekable");
    
private:
    Importer importer_;

public:
    output_type<Importer::dimension, typename Importer::elem_type> output;
    
    template<typename... Args>
    explicit importer_filter(filter_node& nd, Args&&... args) :
        source_filter(nd, false),
        importer_(std::forward<Args>(args)...),
        output(*this)
    {
        set_seekable(true);
    }
    
    void set_seekable(bool seekable) {
        if(seekable) this_node().define_source_stream_properties(true, importer_.total_duration());
        else this_node().define_source_stream_properties(false, -1);
    }
    
    void setup() override {
        output.define_frame_shape(importer_.frame_shape());
    }
    
    void pre_process(node_job& job) override {
        time_unit t = job.time();
        if(importer_.current_time() != t) importer_.seek(t);
    }
    
    void process(node_job& job) override {
        MF_ASSERT(importer_.current_time() == t);
        auto out = job.out(output);
        return importer_.read_frame(out);
    }
};


}}

#endif