RtttlParser.h

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/****
 * Sming Framework Project - Open Source framework for high efficiency native ESP8266 development.
 * Created 2015 by Skurydin Alexey
 * http://github.com/SmingHub/Sming
 * All files of the Sming Core are provided under the LGPL v3 license.
 *
 * RtttlParser.h - Support for reading RTTTL files
 *
 * RTTTL conversion code based on https://github.com/end2endzone/NonBlockingRTTTL
 *
 * @author Sept 2019 mikee47 <mike@sillyhouse.net>
 *
 ****/

#pragma once

#include "StreamBuffer.h"
#include <WString.h>
#include "RingTone.h"

namespace RingTone
{
struct RtttlHeader {
    String title;
    uint8_t defaultNoteDuration = 0; // quarter-note
    uint8_t defaultOctave = 0;
    uint16_t bpm = 0;
};

/*
 * Define core state variables so state can be easily saved/restored
 */
struct RtttlParserState {
    RtttlHeader header;           // Header for current tune
    uint16_t wholeNoteMillis = 0; // Calculated from bpm
    unsigned count = 0;           // Cached number of tunes in the file
    unsigned index = 0;
    unsigned tuneStartPos = 0; // First character after header

    enum {
        rtps_StartOfFile,
        rtps_TuneHeader,
        rtps_TuneContent,
        rtps_EndOfFile,
    } state = rtps_StartOfFile;

    // Only used when saving/restoring state
    unsigned bufferPos = 0;
};

class RtttlParser : public RingTone::Parser, private RtttlParserState
{
public:
    bool begin(IDataSourceStream* source);

    void end();

    bool nextTune();

    bool seekTune(unsigned index);

    unsigned getIndex()
    {
        return index;
    }

    unsigned getCount();

    const String& getTitle()
    {
        return header.title;
    }

    String getCaption()
    {
        String s('#');
        s += index;
        s += ": ";
        s += header.title;
        return s;
    }

    bool rewind()
    {
        if(tuneStartPos == 0) {
            // No current tune
            return false;
        }

        return buffer.setPos(tuneStartPos);
    }

    bool readNextNote(RingTone::NoteDef& note);

    const RtttlHeader& getHeader()
    {
        return header;
    }

    RtttlParserState getState()
    {
        bufferPos = buffer.getPos();
        return *this;
    }

    void setState(const RtttlParserState& state)
    {
        *static_cast<RtttlParserState*>(this) = state;
        buffer.setPos(bufferPos);
    }

private:
    bool readHeader();
    unsigned readNum();

    // Skip whitespace and comment lines
    bool skipWhitespace();

private:
    StreamBuffer<64> buffer;
};

} // namespace RingTone