Kirika/hasher/hasher.go

package hasher

import (
	"crypto/md5"
	"crypto/sha1"
	"crypto/sha256"
	"encoding/binary"
	"git.gammaspectra.live/S.O.N.G/Kirika/audio/format"
	"git.gammaspectra.live/S.O.N.G/Kirika/vector"
	"hash"
	"hash/crc32"
	"sync"
	"time"
)

const TocPregap = 150
const SectorsPerSecond = 75
const DataTrackGap = 11400
const BytesPerSector = 2352
const CDChannels = 2
const Int16SamplesPerSector = BytesPerSector / (2 * CDChannels)
const CDSampleRate = Int16SamplesPerSector * SectorsPerSecond

type HashType int

const (
	HashtypeCrc32 = HashType(iota)
	HashtypeSha256
	HashtypeSha1
	HashtypeMd5
	HashtypeAccurateRipV1
	HashtypeAccurateRipV1Start
	HashtypeAccurateRipV2
	HashtypeAccurateRipV2Start
)

type Hasher struct {
	hash       HashType
	hasher     hash.Hash
	result     []byte
	channel    format.AnalyzerChannel
	wg         sync.WaitGroup
	samples    int
	duration   float64
	sampleRate int
	bitDepth   int
	channels   int
	buffer     [][]int32
}

func NewHasher(channel format.AnalyzerChannel, hashType HashType) (h *Hasher) {
	h = &Hasher{
		hash:    hashType,
		channel: channel,
	}

	switch hashType {
	case HashtypeCrc32:
		h.hasher = crc32.NewIEEE()
	case HashtypeSha256:
		h.hasher = sha256.New()
	case HashtypeSha1:
		h.hasher = sha1.New()
	case HashtypeMd5:
		h.hasher = md5.New()
	case HashtypeAccurateRipV1:
		h.hasher = NewAccurateRipV1(0)
	case HashtypeAccurateRipV1Start:
		h.hasher = NewAccurateRipV1(Int16SamplesPerSector*5 - 1)
	case HashtypeAccurateRipV2:
		h.hasher = NewAccurateRipV2(0)
	case HashtypeAccurateRipV2Start:
		h.hasher = NewAccurateRipV2(Int16SamplesPerSector*5 - 1)

	}

	h.startRoutine()

	return
}

func (h *Hasher) startRoutine() {
	h.wg.Add(1)
	go func() {
		defer h.wg.Done()

		for packet := range h.channel {
			h.handlePacket(packet)
		}

		h.result = h.hasher.Sum([]byte{})

	}()
}

func (h *Hasher) handlePacket(packet *format.AnalyzerPacket) {
	samples := len(packet.Samples) / packet.Channels

	h.samples += samples

	if h.sampleRate == 0 {
		h.sampleRate = packet.SampleRate
	} else if h.sampleRate != packet.SampleRate {
		h.sampleRate = -1
	}
	if h.bitDepth == 0 {
		h.bitDepth = packet.BitDepth
	} else if h.bitDepth != packet.BitDepth {
		h.bitDepth = -1
	}
	if h.channels == 0 {
		h.channels = packet.Channels
	} else if h.channels != packet.Channels {
		h.channels = -1
	}

	h.duration += float64(samples) / float64(packet.SampleRate)

	var buf []byte
	switch packet.BitDepth {
	case 8, 16, 24, 32:
		buf = vector.Int32ToBytes(packet.Samples, packet.BitDepth)
	default:
		buf = make([]byte, len(packet.Samples)*4)
		for i := range packet.Samples {
			binary.LittleEndian.PutUint32(buf[i*4:], uint32(packet.Samples[i]))
		}

	}

	h.hasher.Write(buf)
}

func (h *Hasher) GetSampleCount() int {
	return h.samples
}

func (h *Hasher) GetChannels() int {
	return h.channels
}

func (h *Hasher) GetSampleRate() int {
	return h.sampleRate
}

func (h *Hasher) GetHashType() HashType {
	return h.hash
}

func (h *Hasher) GetResult() []byte {
	return h.result
}

func (h *Hasher) GetDuration() time.Duration {
	if h.sampleRate > 0 {
		return time.Duration(float64(time.Second) * (float64(h.samples) / float64(h.sampleRate)))
	}

	//Fallback calculated duration
	return time.Duration(float64(time.Second) * h.duration)
}

func (h *Hasher) GetWaitGroup() *sync.WaitGroup {
	return &h.wg
}

func (h *Hasher) Wait() {
	h.wg.Wait()
}