radio/lib/wModel/file/audio.cpp

#include "audio.h"

#include <mad.h>

M::Audio::Audio(W::Blob* p_file, const W::Address& addr, QObject* parent):
    File(p_file, addr, parent),
    frames()
{
    W::Handler* requestFrames = W::Handler::create(address + W::Address({u"requestFrames"}), this, &M::Audio::_h_requestFrames);
    
    addHandler(requestFrames);
}

M::Audio::~Audio()
{}

M::Model::ModelType M::Audio::getType() const
{
    return type;
}

void M::Audio::initAdditional(const W::String& p_mime)
{
    File::initAdditional(p_mime);       //TODO handle other than mp3 formats
    
    mad_stream stream;
    mad_header header;
    mad_stream_init(&stream);
    mad_header_init(&header);
    
    mad_stream_buffer(&stream, file->uchar(), file->size());
    
    uint64_t length = 0;
    uint64_t tBits = 0;
    while(stream.error != MAD_ERROR_BUFLEN) {       //TODO handle other errors;
        
        int success = mad_header_decode(&header, &stream);
        if (success == 0) {
            frames.emplace_back(stream.this_frame - stream.buffer, stream.next_frame - stream.this_frame);
            
            length += header.duration.seconds * MAD_TIMER_RESOLUTION + header.duration.fraction;
            tBits += header.bitrate;
        }
    }
    
    additional.insert(u"duration", new W::Uint64(length / MAD_TIMER_RESOLUTION));
    additional.insert(u"bitrate", new W::Uint64(tBits / frames.size()));
    additional.insert(u"framesAmount", new W::Uint64(frames.size()));
}

void M::Audio::h_requestFrames(const W::Event& ev)
{
    const W::Vocabulary& vc = static_cast<const W::Vocabulary&>(ev.getData());
    const W::Uint64& index = static_cast<const W::Uint64&>(vc.at(u"index"));
    const W::Uint64& amount = static_cast<const W::Uint64&>(vc.at(u"amount"));
    
    W::Vocabulary* evc = new W::Vocabulary();
    if (index + amount > frames.size()) {
        evc->insert(u"result", new W::Uint64(1));
    } else {
        evc->insert(u"result", new W::Uint64(0));
        W::Vector* vframes = new W::Vector();
        for (int i = 0; i < amount; ++i) {
            const std::pair<uint64_t, uint64_t>& pair = frames[index + i];      //TODO optimize?
            vframes->push(file->slice(pair.first, pair.second));
        }
        
        evc->insert(u"frames", vframes);
    }
    
    response(evc, W::Address{u"responseFrames"}, ev);
}