MuditaOS/module-audio/Audio/decoder/decoderFLAC.cpp

/*
 *  @file decoderFLAC.cpp
 *  @author Mateusz Piesta (mateusz.piesta@mudita.com)
 *  @date 06.04.19
 *  @brief 
 *  @copyright Copyright (C) 2019 mudita.com
 *  @details
 */

#include "decoderFLAC.hpp"

#define DR_FLAC_IMPLEMENTATION
#define DR_FLAC_NO_STDIO
#define DR_FLAC_NO_OGG
#define DR_FLAC_NO_CRC
#define DR_FLAC_NO_SIMD
#include "dr_flac.h"

namespace decoder {


    decoderFLAC::decoderFLAC(const char *fileName)
            : decoder(fileName),
              tags(std::make_unique<Tags>()) {

        flac = drflac_open_with_metadata(drflac_read, drflac_seek, drflac_meta, this);
        if (flac == NULL) {
            //error
        }
    }


    decoderFLAC::~decoderFLAC() {
        drflac_close(flac);
    }


    std::unique_ptr<Tags> decoderFLAC::fetchTags() {
        tags->filePath.append(filePath);
        if(tags->title.size() == 0){
            auto pos = filePath.rfind("/");
            if (pos == std::string::npos) {
                tags->title.append(filePath);
            } else {
                tags->title.append(&filePath[pos]);
            }
        }
        return std::make_unique<Tags>(*tags);
    }


    uint32_t decoderFLAC::decode(uint32_t samplesToRead, int16_t *pcmData) {

        uint32_t samples_read = 0;
        uint32_t samplesToReadChann = chanNumber == 1 ? samplesToRead / 2 : samplesToRead;

        // Mono
        if (chanNumber == 1) {
            samples_read = drflac_read_s16(flac, samplesToReadChann, (drflac_int16 *) pcmData);

            // Internally mono recordings are converted to stereo by doubling samples.
            decoder::convertmono2stereo(pcmData, samplesToReadChann);
            samplesToReadChann *=2;
            samples_read *=2;
        }
            // Stereo
        else {
            samples_read = drflac_read_s16(flac, samplesToReadChann, (drflac_int16 *) pcmData);
        }

        if (samples_read) {
            /* Calculate frame duration in seconds */
            position += (float) ((float) (samplesToReadChann / 2) / (float) sampleRate);
        }

        return samples_read;
    }

    void decoderFLAC::setPosition(float pos){

        drflac_seek_to_sample(flac,totalSamplesCount*pos);

        // Calculate new position
        position = (float) ((float) (totalSamplesCount*pos)/chanNumber / (float) (sampleRate));
    }


/* Data encoded in UTF-8 */
    void decoderFLAC::flac_parse_text(uint8_t *in, uint32_t taglen, uint32_t datalen, uint8_t *out, uint32_t outlen) {
        /* Little Endian here. */
        uint32_t size = datalen - taglen > outlen - 1 ? outlen - 1 : datalen - taglen;
        memcpy(out, in + taglen, size);
        out[size] = '\0';
    }


    size_t decoderFLAC::drflac_read(void *pUserData, void *pBufferOut, size_t bytesToRead) {
        decoderFLAC *userdata = (decoderFLAC *) pUserData;
        return core::vfs::fread(pBufferOut, 1, bytesToRead, userdata->fd);
    }


    drflac_bool32 decoderFLAC::drflac_seek(void *pUserData, int offset, drflac_seek_origin origin) {
        decoderFLAC *userdata = (decoderFLAC *) pUserData;
        return !core::vfs::fseek(userdata->fd, offset, origin == drflac_seek_origin_start ? SEEK_SET : SEEK_CUR);
    }


    void decoderFLAC::drflac_meta(void *pUserData, drflac_metadata *pMetadata) {
        decoderFLAC *userdata = (decoderFLAC *) pUserData;

        /* We're only interested in VORBIS comments which contain album/track/artist info */
        if (pMetadata->type == DRFLAC_METADATA_BLOCK_TYPE_VORBIS_COMMENT) {
            uint8_t buff[128] = {0};

            /*ommit vendor string*/
            uint8_t *p = (uint8_t *) pMetadata->data.vorbis_comment.comments;

            uint8_t i = 0;
            for (i = 0; i < pMetadata->data.vorbis_comment.commentCount; i++) {
                /* Little Endian */
                uint32_t *taglen = (uint32_t *) p;
                p += sizeof(*taglen);


                uint8_t *pp = (uint8_t *) strchr((char *) p, '=');
                uint8_t j = 0;
                uint32_t tolower_size = pp - p;
                /*convert to lower case*/
                for (j = 0; j < tolower_size; ++j) p[j] = tolower(p[j]);

                if (!memcmp(p, "artist=", 7)) {
                    userdata->flac_parse_text(p, 7, *taglen, buff, sizeof buff);
                    userdata->tags->artist.append(reinterpret_cast<char *>(&buff[0]));
                }

                if (!memcmp(p, "title=", 6)) {
                    userdata->flac_parse_text(p, 6, *taglen, buff, sizeof buff);
                    userdata->tags->title.append(reinterpret_cast<char *>(&buff[0]));
                }

                if (!memcmp(p, "album=", 6)) {
                    userdata->flac_parse_text(p, 6, *taglen, buff, sizeof buff);
                    userdata->tags->album.append(reinterpret_cast<char *>(&buff[0]));
                }

                if (!memcmp(p, "genre=", 6)) {
                    userdata->flac_parse_text(p, 6, *taglen, buff, sizeof buff);
                    userdata->tags->genre.append(reinterpret_cast<char *>(&buff[0]));
                }

                if (!memcmp(p, "date=", 5)) {
                    userdata->flac_parse_text(p, 5, *taglen, buff, sizeof buff);
                    userdata->tags->year.append(reinterpret_cast<char *>(&buff[0]));
                }

                p += *taglen;
            }
        } else if (pMetadata->type == DRFLAC_METADATA_BLOCK_TYPE_STREAMINFO) {
            userdata->tags->total_duration_s =
                    (pMetadata->data.streaminfo.totalSampleCount / (pMetadata->data.streaminfo.bitsPerSample / 8)) /
                    pMetadata->data.streaminfo.sampleRate;

            if(pMetadata->data.streaminfo.channels == 1){
                userdata->tags->total_duration_s *=2;
            }

            userdata->tags->duration_min = userdata->tags->total_duration_s / 60;
            userdata->tags->duration_hour = userdata->tags->duration_min / 60;
            userdata->tags->duration_sec = userdata->tags->total_duration_s % 60;
            userdata->tags->sample_rate = pMetadata->data.streaminfo.sampleRate;
            userdata->tags->num_channel = pMetadata->data.streaminfo.channels;

            userdata->sampleRate = pMetadata->data.streaminfo.sampleRate;
            userdata->chanNumber = pMetadata->data.streaminfo.channels;

            userdata->totalSamplesCount = pMetadata->data.streaminfo.totalSampleCount;
        }

    }

}