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PCM.go
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PCM.go
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package signals
import (
"io"
"os"
"io/ioutil"
"path"
"strconv"
"errors"
)
// PCM is the common state embedded in all the different precisions of PCM signals, it doesn't itself include encoding information, so cannot return a property and so is not a Signal.
// PCM Signals return continuous property values that step from one PCM value to the next, Segmented could be used to get interpolated property values.
type PCM struct {
samplePeriod x
Data []byte
}
// make a PCM type, from raw bytes.
func NewPCM(sampleRate uint32, Data []byte) PCM {
return PCM{X(1 / float32(sampleRate)), Data}
}
func (s PCM) Period() x {
return s.samplePeriod
}
// loads, in advanced way, a PCM from provided path.
// if the path has a numerical name, that is taken as the loaded sampleRate, and the PCM is set to it.
// if it isn't, the subfolder with a name equal to the provided PCM's sample rate is loaded. (PCM sample rate unchanged.)
// actual data is taken from files with extension ".pcm".
func LoadPCM(pathTo string, p *PCM) (err error) {
sampleRate,err:=strconv.ParseUint(path.Base(path.Dir(pathTo)), 10, 32)
if err!=nil {
if p.samplePeriod==0 {
var files []os.FileInfo
files, err = ioutil.ReadDir(path.Dir(pathTo))
if err != nil {return}
for _, file := range files {
if file.IsDir() && file.Size()>0 {
sampleRate,err=strconv.ParseUint(file.Name(), 10, 32)
if err==nil {
pathTo=path.Join(path.Dir(pathTo),file.Name(),path.Base(pathTo))
break
}
}
}
}else{
pathTo=path.Join(path.Dir(pathTo),strconv.FormatInt(int64(unitX / x(p.samplePeriod)),10),path.Base(pathTo))
}
}else{
p.samplePeriod=X(1 / float32(sampleRate))
}
p.Data,err=ioutil.ReadFile(pathTo+".pcm")
return
}
// save PCM into a given path's sub-folder depending on its sample rate. (see LoadPCM)
func SavePCM(path string,pcm PCM) error {
return pcm.SaveTo(path)
}
// save the PCM to a given path, which if not ending in a folder with the PCM's Sample Rate as its name, will add it as a sub-folder.
// This means the file won't then actually simply be at the 'path' address, separate folders for each saved Sample Rate will be generated.
// using LoadPCM will automatically find it. Also adds extension ".pcm".
func (p PCM) SaveTo(pathTo string) error {
sampleRate,err:=strconv.ParseUint(path.Base(path.Dir(pathTo)), 10, 32)
if err!=nil {
pathTo=path.Join(path.Dir(pathTo),strconv.FormatInt(int64(unitX / x(p.samplePeriod)),10),path.Base(pathTo))
err:=os.Mkdir(path.Dir(pathTo), os.ModeDir | 0775)
if err!=nil && !os.IsExist(err){return err}
}else{
if p.samplePeriod!=unitX / x(sampleRate) {return errors.New("parent folder for different sample rate.")}
}
file, err := os.Create(pathTo+".pcm")
if err!=nil {return err}
file.Write(p.Data)
return file.Close()
}
// from a PCM return two new PCM's (with the same underlying data) from either side of a sample.
func (s PCM) Split(sample uint32, sampleBytes uint8) (head PCM, tail PCM) {
copy := func(s PCM) PCM { return s }
bytePosition := sample * uint32(sampleBytes)
if bytePosition > uint32(len(s.Data)) {
bytePosition = uint32(len(s.Data))
}
head, tail = s, copy(s)
tail.Data = tail.Data[bytePosition:]
head.Data = head.Data[:bytePosition]
return
}
// 8 bit PCM Signal.
type PCM8bit struct {
PCM
}
func NewPCM8bit(sampleRate uint32, Data []byte) PCM8bit {
return PCM8bit{NewPCM(sampleRate, Data)}
}
func (s PCM8bit) property(p x) y {
index := int(p / s.samplePeriod)
if index < 0 || index >= len(s.Data){
return 0
}
return decodePCM8bit(s.Data[index])
}
func encodePCM8bit(v y) byte {
return byte(v>>(yBits-8)) + 128
}
func decodePCM8bit(b byte) y {
return y(b-128) << (yBits-8)
}
func (s PCM8bit) MaxX() x {
return s.PCM.samplePeriod * x(len(s.PCM.Data)-1)
}
func (s PCM8bit) Encode(w io.Writer) {
Encode(w, 1, uint32(unitX/s.Period()), s.MaxX(), s)
}
func (s PCM8bit) Split(p x) (PCM8bit, PCM8bit) {
head, tail := s.PCM.Split(uint32(p/s.PCM.samplePeriod)+1, 1)
return PCM8bit{head}, PCM8bit{tail}
}
// 16 bit PCM Signal
type PCM16bit struct {
PCM
}
func NewPCM16bit(sampleRate uint32, Data []byte) PCM16bit {
return PCM16bit{NewPCM(sampleRate, Data)}
}
func (s PCM16bit) property(p x) y {
index := int(p/s.samplePeriod) * 2
if index < 0 || index >= len(s.Data)-1 {
return 0
}
return decodePCM16bit(s.Data[index], s.Data[index+1])
}
func encodePCM16bit(v y) (byte, byte) {
return byte(v >> (yBits - 16)), byte(v >> (yBits - 8))
}
func decodePCM16bit(b1, b2 byte) y {
return y(b1) << (yBits-16)|y(b2) << (yBits-8)
}
func (s PCM16bit) Encode(w io.Writer) {
Encode(w, 2, uint32(unitX/s.Period()), s.MaxX(), s)
}
func (s PCM16bit) MaxX() x {
return s.PCM.samplePeriod * x(len(s.PCM.Data)-2) / 2
}
func (s PCM16bit) Split(p x) (PCM16bit, PCM16bit) {
head, tail := s.PCM.Split(uint32(p/s.PCM.samplePeriod)+1, 2)
return PCM16bit{head}, PCM16bit{tail}
}
// 24 bit PCM Signal
type PCM24bit struct {
PCM
}
func NewPCM24bit(sampleRate uint32, Data []byte) PCM24bit {
return PCM24bit{NewPCM(sampleRate, Data)}
}
func (s PCM24bit) property(p x) y {
index := int(p/s.samplePeriod) * 3
if index < 0 || index >= len(s.Data)-2 {
return 0
}
return decodePCM24bit(s.Data[index], s.Data[index+1], s.Data[index+2])
}
func encodePCM24bit(v y) (byte, byte, byte) {
return byte(v >> (yBits - 24)), byte(v >> (yBits - 16)), byte(v >> (yBits - 8))
}
func decodePCM24bit(b1, b2, b3 byte) y {
return y(b1) << (yBits-24)|y(b2) << (yBits-16)|y(b3) << (yBits-8)
}
func (s PCM24bit) Encode(w io.Writer) {
Encode(w, 3, uint32(unitX/s.Period()), s.MaxX(), s)
}
func (s PCM24bit) MaxX() x {
return s.PCM.samplePeriod * x(len(s.PCM.Data)-3) / 3
}
func (s PCM24bit) Split(p x) (PCM24bit, PCM24bit) {
head, tail := s.PCM.Split(uint32(p/s.PCM.samplePeriod)+1, 3)
return PCM24bit{head}, PCM24bit{tail}
}
// 32 bit PCM Signal
type PCM32bit struct {
PCM
}
func NewPCM32bit(sampleRate uint32, Data []byte) PCM32bit {
return PCM32bit{NewPCM(sampleRate, Data)}
}
func (s PCM32bit) property(p x) y {
index := int(p/s.samplePeriod) * 4
if index < 0 || index >= len(s.Data)-3 {
return 0
}
return decodePCM32bit(s.Data[index], s.Data[index+1], s.Data[index+2], s.Data[index+3])
}
func encodePCM32bit(v y) (byte, byte, byte, byte) {
return byte(v >> (yBits - 32)), byte(v >> (yBits - 24)), byte(v >> (yBits - 16)), byte(v >> (yBits - 8))
}
func decodePCM32bit(b1, b2, b3, b4 byte) y {
return y(b1) << (yBits-32)|y(b2) << (yBits-24)|y(b3) << (yBits-16)|y(b4) << (yBits-8)
}
func (s PCM32bit) Encode(w io.Writer) {
Encode(w, 4, uint32(unitX/s.Period()), s.MaxX(), s)
}
func (s PCM32bit) MaxX() x {
return s.PCM.samplePeriod * x(len(s.PCM.Data)-4) / 4
}
func (s PCM32bit) Split(p x) (PCM32bit, PCM32bit) {
head, tail := s.PCM.Split(uint32(p/s.PCM.samplePeriod)+1, 4)
return PCM32bit{head}, PCM32bit{tail}
}
// 48 bit PCM Signal
type PCM48bit struct {
PCM
}
func NewPCM48bit(sampleRate uint32, Data []byte) PCM48bit {
return PCM48bit{NewPCM(sampleRate, Data)}
}
func (s PCM48bit) property(p x) y {
index := int(p/s.samplePeriod) * 6
if index < 0 || index >= len(s.Data)-5 {
return 0
}
return decodePCM48bit(s.Data[index], s.Data[index+1], s.Data[index+2], s.Data[index+3], s.Data[index+4], s.Data[index+5])
}
func encodePCM48bit(v y) (byte, byte, byte, byte, byte, byte) {
return byte(v >> (yBits - 48)), byte(v >> (yBits - 40)), byte(v >> (yBits - 32)), byte(v >> (yBits - 24)), byte(v >> (yBits - 16)), byte(v >> (yBits - 8))
}
func decodePCM48bit(b1, b2, b3, b4, b5, b6 byte) y {
return y(b1) << (yBits-48)|y(b2) << (yBits-40)|y(b3) << (yBits-32)|y(b4) << (yBits-24)|y(b5) << (yBits-16)|y(b6) << (yBits-8)
}
func (s PCM48bit) Encode(w io.Writer) {
Encode(w, 6, uint32(unitX/s.Period()), s.MaxX(), s)
}
func (s PCM48bit) MaxX() x {
return s.PCM.samplePeriod * x(len(s.PCM.Data)-6) / 6
}
func (s PCM48bit) Split(p x) (PCM48bit, PCM48bit) {
head, tail := s.PCM.Split(uint32(p/s.PCM.samplePeriod)+1, 6)
return PCM48bit{head}, PCM48bit{tail}
}
// 64 bit PCM Signal
type PCM64bit struct {
PCM
}
func NewPCM64bit(sampleRate uint32, Data []byte) PCM64bit {
return PCM64bit{NewPCM(sampleRate, Data)}
}
func (s PCM64bit) property(p x) y {
index := int(p/s.samplePeriod) * 8
if index < 0 || index >= len(s.Data)-7 {
return 0
}
return decodePCM64bit(s.Data[index], s.Data[index+1], s.Data[index+2], s.Data[index+3], s.Data[index+4], s.Data[index+5], s.Data[index+6], s.Data[index+7])
}
func encodePCM64bit(v y) (byte, byte, byte, byte, byte, byte, byte, byte) {
return byte(v >> (yBits - 64)), byte(v >> (yBits - 56)),byte(v >> (yBits - 48)), byte(v >> (yBits - 40)), byte(v >> (yBits - 32)), byte(v >> (yBits - 24)), byte(v >> (yBits - 16)), byte(v >> (yBits - 8))
}
func decodePCM64bit(b1, b2, b3, b4, b5, b6 , b7, b8 byte) y {
return y(b1) << (yBits-64)|y(b1) << (yBits-56)|y(b1) << (yBits-48)|y(b2) << (yBits-40)|y(b3) << (yBits-32)|y(b4) << (yBits-24)|y(b5) << (yBits-16)|y(b6) << (yBits-8)
}
func (s PCM64bit) Encode(w io.Writer) {
Encode(w, 8, uint32(unitX/s.Period()), s.MaxX(), s)
}
func (s PCM64bit) MaxX() x {
return s.PCM.samplePeriod * x(len(s.PCM.Data)-8) / 8
}
func (s PCM64bit) Split(p x) (PCM64bit, PCM64bit) {
head, tail := s.PCM.Split(uint32(p/s.PCM.samplePeriod)+1, 8)
return PCM64bit{head}, PCM64bit{tail}
}
// make a PeriodicLimitedSignal by sampling from a Signal, using provided parameters.
func NewPCMSignal(s Signal, length x, sampleRate uint32, sampleBytes uint8) PeriodicLimitedSignal {
out, in := io.Pipe()
go func() {
Encode(in, sampleBytes, sampleRate, length, s)
in.Close()
}()
channels, _ := Decode(out)
out.Close()
return channels[0]
}