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module.go
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module.go
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package ibxmgo
import (
"bufio"
"bytes"
"encoding/binary"
"errors"
// "fmt"
"io"
"io/ioutil"
)
type C2Rate int
const (
NTSC = C2Rate(8363)
PAL = C2Rate(8287)
FP_SHIFT = 15
FP_ONE = 1 << FP_SHIFT
FP_MASK = FP_ONE - 1
/* Constants for the 16-tap fixed-point sinc interpolator. */
LOG2_FILTER_TAPS = 4
FILTER_TAPS = 1 << LOG2_FILTER_TAPS
DELAY = FILTER_TAPS / 2
LOG2_TABLE_ACCURACY = 4
TABLE_ACCURACY = 1 << LOG2_TABLE_ACCURACY
TABLE_INTERP_SHIFT = FP_SHIFT - LOG2_TABLE_ACCURACY
TABLE_INTERP_ONE = 1 << TABLE_INTERP_SHIFT
TABLE_INTERP_MASK = TABLE_INTERP_ONE - 1
)
var (
xmHeader = []byte("Extended Module: ")
formats []format
deltaEnvHeader = []byte("DigiBooster Pro")
UnsupportedFormat = errors.New("Unsupported format")
keyToPeriod = []int{
29020, 27392, 25855, 24403, 23034, 21741, 20521,
19369, 18282, 17256, 16287, 15373, 14510, 13696,
}
)
type format struct {
name string
check func(r *bufio.Reader) bool
decode func(r *bufio.Reader) (*Module, error)
}
type Instrument struct {
name string
vibratoType, vibratoSweep, vibratoDepth, vibratoRate int
volumeFadeOut int
numSamples int
samples []*Sample
keyToSample [97]int
volumeEnvelope *Envelope
panningEnvelope *Envelope
}
func DefaultInstrument() *Instrument {
return &Instrument{
numSamples: 1,
volumeEnvelope: DefaultEnvelope(),
panningEnvelope: DefaultEnvelope(),
samples: []*Sample{&Sample{}},
}
}
type Module struct {
songName string
numChannels, numInstruments int
numPatterns, sequenceLength, restartPos int
defaultGVol, defaultSpeed, defaultTempo, gain int
c2Rate C2Rate
linearPeriods, fastVolSlides bool
defaultPanning []int
sequence []int
patterns []*Pattern
instruments []*Instrument
}
func NewModule() *Module {
return &Module{
songName: "Blank",
numChannels: 4,
numInstruments: 1,
numPatterns: 1,
sequenceLength: 1,
defaultGVol: 64,
defaultSpeed: 6,
defaultTempo: 125,
c2Rate: PAL,
gain: 64,
instruments: []*Instrument{DefaultInstrument(), DefaultInstrument()},
patterns: []*Pattern{NewPattern(4, 64)},
sequence: []int{0},
defaultPanning: []int{51, 204, 204, 51},
}
}
func RegisterFormat(name string, check func(r *bufio.Reader) bool, decode func(r *bufio.Reader) (*Module, error)) {
formats = append(formats, format{name, check, decode})
}
func init() {
RegisterFormat("xm", IsXM, DecodeXM)
RegisterFormat("mod", IsMOD, DecodeMOD)
RegisterFormat("s3m", IsS3M, DecodeS3M)
}
func Decode(r io.Reader) (*Module, error) {
reader := bufio.NewReader(r)
for _, f := range formats {
if f.check(reader) {
return f.decode(reader)
}
}
return nil, UnsupportedFormat
}
func IsXM(reader *bufio.Reader) bool {
header, e := reader.Peek(17)
if e != nil {
return false
}
return bytes.Equal(header[0:17], xmHeader)
}
func IsMOD(reader *bufio.Reader) bool {
header, e := reader.Peek(1084)
if e != nil {
return false
}
modFormat := binary.BigEndian.Uint16(header[1082:])
return modFormat == 0x4b2e || modFormat == 0x4b21 || modFormat == 0x5434 ||
modFormat == 0x484e || modFormat == 0x4348
}
func IsS3M(reader *bufio.Reader) bool {
header, e := reader.Peek(48)
if e != nil {
return false
}
return binary.LittleEndian.Uint32(header[44:]) == 0x4d524353
}
func DecodeS3M(reader *bufio.Reader) (*Module, error) {
buff, e := ioutil.ReadAll(reader)
if e != nil {
return nil, e
}
m := NewModule()
m.songName = string(buff[0:28])
m.sequenceLength = int(binary.LittleEndian.Uint16(buff[32:]))
m.numInstruments = int(binary.LittleEndian.Uint16(buff[34:]))
m.numPatterns = int(binary.LittleEndian.Uint16(buff[36:]))
flags := binary.LittleEndian.Uint16(buff[38:])
version := binary.LittleEndian.Uint16(buff[40:])
m.fastVolSlides = ((flags & 0x40) == 0x40) || version == 0x1300
signedSamples := binary.LittleEndian.Uint16(buff[42:]) == 1
if binary.LittleEndian.Uint32(buff[44:]) != 0x4d524353 {
errors.New("Not an S3M file!")
}
m.defaultGVol = int(buff[48])
m.defaultSpeed = int(buff[49])
m.defaultTempo = int(buff[50])
m.c2Rate = NTSC
m.gain = int(buff[51] & 0x7F)
stereoMode := (buff[51] & 0x80) == 0x80
defaultPan := (buff[53] & 0xFF) == 0xFC
channelMap := make([]int, 32)
for chanIdx := 0; chanIdx < 32; chanIdx++ {
channelMap[chanIdx] = -1
if buff[64+chanIdx] < 16 {
channelMap[chanIdx] = m.numChannels
m.numChannels++
}
}
m.sequence = make([]int, m.sequenceLength)
for seqIdx := 0; seqIdx < m.sequenceLength; seqIdx++ {
m.sequence[seqIdx] = int(buff[96+seqIdx])
}
moduleDataIdx := 96 + m.sequenceLength
m.instruments = make([]*Instrument, m.numInstruments+1)
m.instruments[0] = DefaultInstrument()
for instIdx := 1; instIdx <= m.numInstruments; instIdx++ {
instrument := DefaultInstrument()
m.instruments[instIdx] = instrument
sample := instrument.samples[0]
instOffset := int(binary.LittleEndian.Uint16(buff[moduleDataIdx:])) << 4
moduleDataIdx += 2
instrument.name = string(buff[instOffset+48 : instOffset+48+28])
if buff[instOffset] != 1 {
continue
}
if binary.LittleEndian.Uint16(buff[instOffset+76:]) != 0x4353 {
continue
}
sampleOffset := int(buff[instOffset+13]) << 20
sampleOffset += int(binary.LittleEndian.Uint16(buff[instOffset+14:])) << 4
sampleLength := int(binary.LittleEndian.Uint32(buff[instOffset+16:]))
loopStart := int(binary.LittleEndian.Uint32(buff[instOffset+20:]))
loopLength := int(binary.LittleEndian.Uint32(buff[instOffset+24:])) - loopStart
sample.volume = int(buff[instOffset+28])
sample.panning = -1
packed := buff[instOffset+30] != 0
loopOn := (buff[instOffset+31] & 0x1) == 0x1
if loopStart+loopLength > sampleLength {
loopLength = sampleLength - loopStart
}
if loopLength < 1 || !loopOn {
loopStart = sampleLength
loopLength = 0
}
stereo := (buff[instOffset+31] & 0x2) == 0x2
_ = stereo
sixteenBit := (buff[instOffset+31] & 0x4) == 0x4
if packed {
errors.New("Packed samples not supported!")
}
sample.c2Rate = C2Rate(binary.LittleEndian.Uint32(buff[instOffset+32:]))
sampleData := make([]int16, loopStart+loopLength)
if sixteenBit {
if signedSamples {
for idx, end := 0, len(sampleData); idx < end; idx++ {
sampleData[idx] = (int16)(int16(buff[sampleOffset]) | (int16(buff[sampleOffset+1]) << 8))
sampleOffset += 2
}
} else {
for idx, end := 0, len(sampleData); idx < end; idx++ {
sam := int(buff[sampleOffset]) | (int(buff[sampleOffset+1]) << 8)
sampleData[idx] = (int16)(sam - 32768)
sampleOffset += 2
}
}
} else {
if signedSamples {
for idx, end := 0, len(sampleData); idx < end; idx++ {
sampleData[idx] = (int16)(buff[sampleOffset]) << 8
sampleOffset++
}
} else {
for idx, end := 0, len(sampleData); idx < end; idx++ {
sampleData[idx] = (int16)((int(buff[sampleOffset]) - 128) << 8)
sampleOffset++
}
}
}
sample.setSampleData(sampleData, loopStart, loopLength, false)
}
m.patterns = make([]*Pattern, m.numPatterns)
for patIdx := 0; patIdx < m.numPatterns; patIdx++ {
pattern := NewPattern(m.numChannels, 64)
m.patterns[patIdx] = pattern
inOffset := (binary.LittleEndian.Uint16(buff[moduleDataIdx:]) << 4) + 2
rowIdx := 0
for rowIdx < 64 {
token := buff[inOffset]
inOffset++
if token == 0 {
rowIdx++
continue
}
noteKey := 0
noteIns := 0
if (token & 0x20) == 0x20 { /* Key + Instrument.*/
noteKey = int(buff[inOffset])
inOffset++
noteIns = int(buff[inOffset])
inOffset++
if noteKey < 0xFE {
noteKey = (noteKey>>4)*12 + (noteKey & 0xF) + 1
}
if noteKey == 0xFF {
noteKey = 0
}
}
noteVol := 0
if (token & 0x40) == 0x40 { /* Volume Column.*/
noteVol = int(buff[inOffset]&0x7F) + 0x10
inOffset++
if noteVol > 0x50 {
noteVol = 0
}
}
noteEffect := 0
noteParam := 0
if (token & 0x80) == 0x80 { /* Effect + Param.*/
noteEffect = int(buff[inOffset])
inOffset++
noteParam = int(buff[inOffset])
inOffset++
if noteEffect < 1 || noteEffect >= 0x40 {
noteEffect = 0
noteParam = 0
}
if noteEffect > 0 {
noteEffect += 0x80
}
}
chanIdx := channelMap[token&0x1F]
if chanIdx >= 0 {
noteOffset := (rowIdx*m.numChannels + chanIdx) * 5
pattern.data[noteOffset] = (byte)(noteKey)
pattern.data[noteOffset+1] = (byte)(noteIns)
pattern.data[noteOffset+2] = (byte)(noteVol)
pattern.data[noteOffset+3] = (byte)(noteEffect)
pattern.data[noteOffset+4] = (byte)(noteParam)
}
}
moduleDataIdx += 2
}
m.defaultPanning = make([]int, m.numChannels)
for chanIdx := 0; chanIdx < 32; chanIdx++ {
if channelMap[chanIdx] < 0 {
continue
}
panning := 7
if stereoMode {
panning = 12
if buff[64+chanIdx] < 8 {
panning = 3
}
}
if defaultPan {
panFlags := buff[moduleDataIdx+chanIdx]
if (panFlags & 0x20) == 0x20 {
panning = int(panFlags & 0xF)
}
}
m.defaultPanning[channelMap[chanIdx]] = panning * 17
}
return m, nil
}
func DecodeMOD(reader *bufio.Reader) (*Module, error) {
buff, e := ioutil.ReadAll(reader)
if e != nil {
return nil, e
}
m := NewModule()
m.songName = string(buff[0:20])
m.sequenceLength = int(buff[950] & 0x7F)
m.restartPos = int(buff[951] & 0x7F)
if m.restartPos >= m.sequenceLength {
m.restartPos = 0
}
m.sequence = make([]int, 128)
for seqIdx := 0; seqIdx < 128; seqIdx++ {
patIdx := int(buff[952+seqIdx] & 0x7F)
m.sequence[seqIdx] = patIdx
if patIdx >= m.numPatterns {
m.numPatterns = patIdx + 1
}
}
switch binary.BigEndian.Uint16(buff[1082:]) {
case 0x4b2e: /* M.K. */
fallthrough
case 0x4b21: /* M!K! */
fallthrough
case 0x5434: /* FLT4 */
m.numChannels = 4
m.c2Rate = PAL
m.gain = 64
break
case 0x484e: /* xCHN */
m.numChannels = int(int8(buff[1080])) - 48
m.c2Rate = NTSC
m.gain = 32
break
case 0x4348: /* xxCH */
m.numChannels = (int(int8(buff[1080])) - 48) * 10
m.numChannels += int(int8(buff[1081])) - 48
m.c2Rate = NTSC
m.gain = 32
break
default:
panic("MOD Format not recognised!")
}
m.defaultGVol = 64
m.defaultSpeed = 6
m.defaultTempo = 125
m.defaultPanning = make([]int, m.numChannels)
for idx := 0; idx < m.numChannels; idx++ {
m.defaultPanning[idx] = 51
if (idx&3) == 1 || (idx&3) == 2 {
m.defaultPanning[idx] = 204
}
}
moduleDataIdx := 1084
m.patterns = make([]*Pattern, m.numPatterns)
for patIdx := 0; patIdx < m.numPatterns; patIdx++ {
pattern := NewPattern(m.numChannels, 64)
m.patterns[patIdx] = pattern
for patDataIdx := 0; patDataIdx < len(pattern.data); patDataIdx += 5 {
period := int(buff[moduleDataIdx]&0xF) << 8
period = (period | int(buff[moduleDataIdx+1])) * 4
if period > 112 {
key, oct := 0, 0
for period < 14510 {
period *= 2
oct++
}
for key < 12 {
d1 := keyToPeriod[key] - period
d2 := period - keyToPeriod[key+1]
if d2 >= 0 {
if d2 < d1 {
key++
}
break
}
key++
}
pattern.data[patDataIdx] = (byte)(oct*12 + key)
}
ins := int(buff[moduleDataIdx+2]&0xF0) >> 4
ins = ins | int(buff[moduleDataIdx]&0x10)
pattern.data[patDataIdx+1] = (byte)(ins)
effect := buff[moduleDataIdx+2] & 0x0F
param := buff[moduleDataIdx+3] & 0xFF
if param == 0 && (effect < 3 || effect == 0xA) {
effect = 0
}
if param == 0 && (effect == 5 || effect == 6) {
effect -= 2
}
if effect == 8 && m.numChannels == 4 {
effect = 0
param = 0
}
pattern.data[patDataIdx+3] = (byte)(effect)
pattern.data[patDataIdx+4] = (byte)(param)
moduleDataIdx += 4
}
}
m.numInstruments = 31
m.instruments = make([]*Instrument, m.numInstruments+1)
m.instruments[0] = DefaultInstrument()
for instIdx := 1; instIdx <= m.numInstruments; instIdx++ {
instrument := DefaultInstrument()
m.instruments[instIdx] = instrument
sample := instrument.samples[0]
instrument.name = string(buff[instIdx*30-10 : instIdx*30-10+22])
sampleLength := int(binary.BigEndian.Uint16(buff[instIdx*30+12:])) * 2
fineTune := int(buff[instIdx*30+14]&0xF) << 4
sample.fineTune = fineTune - 256
if fineTune < 128 {
sample.fineTune = fineTune
}
volume := buff[instIdx*30+15] & 0x7F
sample.volume = 64
if volume <= 64 {
sample.volume = int(volume)
}
sample.panning = -1
sample.c2Rate = m.c2Rate
loopStart := int(binary.BigEndian.Uint16(buff[instIdx*30+16:])) * 2
loopLength := int(binary.BigEndian.Uint16(buff[instIdx*30+18:])) * 2
sampleData := make([]int16, sampleLength)
if moduleDataIdx+sampleLength > len(buff) {
sampleLength = len(buff) - moduleDataIdx
}
if loopStart+loopLength > sampleLength {
loopLength = sampleLength - loopStart
}
if loopLength < 4 {
loopStart = sampleLength
loopLength = 0
}
for idx, end := 0, sampleLength; idx < end; idx++ {
sampleData[idx] = (int16)(int8(buff[moduleDataIdx])) << 8
moduleDataIdx++
}
sample.setSampleData(sampleData, loopStart, loopLength, false)
}
return m, nil
}
func DecodeXM(reader *bufio.Reader) (*Module, error) {
buff, e := ioutil.ReadAll(reader)
if e != nil {
return nil, e
}
if buff[58] != 0x04 && buff[59] != 0x01 {
return nil, errors.New("XM format version must be 0x0104!")
}
m := NewModule()
m.songName = string(buff[17:37])
deltaEnv := bytes.Equal(buff[38:38+len(deltaEnvHeader)], deltaEnvHeader)
dataOffset := 60 + binary.LittleEndian.Uint32(buff[60:])
m.sequenceLength = int(binary.LittleEndian.Uint16(buff[64:]))
m.restartPos = int(binary.LittleEndian.Uint16(buff[66:]))
m.numChannels = int(binary.LittleEndian.Uint16(buff[68:]))
m.numPatterns = int(binary.LittleEndian.Uint16(buff[70:]))
m.numInstruments = int(binary.LittleEndian.Uint16(buff[72:]))
m.linearPeriods = (binary.LittleEndian.Uint16(buff[74:]) & 0x1) > 0
m.defaultGVol = 64
m.defaultSpeed = int(binary.LittleEndian.Uint16(buff[76:]))
m.defaultTempo = int(binary.LittleEndian.Uint16(buff[78:]))
m.c2Rate = NTSC
sequenceLength := m.sequenceLength
numChannels := m.numChannels
numPatterns := m.numPatterns
numInstruments := m.numInstruments
m.defaultPanning = make([]int, numChannels)
m.sequence = make([]int, sequenceLength)
m.patterns = make([]*Pattern, numPatterns)
m.instruments = make([]*Instrument, numInstruments+1)
defaultPanning := m.defaultPanning
sequence := m.sequence
patterns := m.patterns
instruments := m.instruments
for i := 0; i < numChannels; i++ {
defaultPanning[i] = 128
}
for seqIdx := 0; seqIdx < sequenceLength; seqIdx++ {
entry := buff[80+seqIdx]
if int(entry) < numPatterns {
sequence[seqIdx] = int(entry)
}
}
for patIdx := 0; patIdx < numPatterns; patIdx++ {
if buff[dataOffset+4] != 0 {
return nil, errors.New("Unknown pattern packing type!")
}
numRows := int(binary.LittleEndian.Uint16(buff[dataOffset+5:]))
numNotes := numRows * numChannels
pattern := NewPattern(numChannels, numRows)
patterns[patIdx] = pattern
patternDataLength := uint32(binary.LittleEndian.Uint16(buff[dataOffset+7:]))
dataOffset += binary.LittleEndian.Uint32(buff[dataOffset:])
nextOffset := dataOffset + patternDataLength
if patternDataLength > 0 {
patternDataOffset := 0
for note := 0; note < numNotes; note++ {
flags := buff[dataOffset]
if (flags & 0x80) == 0 {
flags = 0x1F
} else {
dataOffset++
}
if (flags & 0x01) > 0 {
pattern.data[patternDataOffset] = buff[dataOffset]
dataOffset++
}
patternDataOffset++
if (flags & 0x02) > 0 {
pattern.data[patternDataOffset] = buff[dataOffset]
dataOffset++
}
patternDataOffset++
if (flags & 0x04) > 0 {
pattern.data[patternDataOffset] = buff[dataOffset]
dataOffset++
}
patternDataOffset++
fxc, fxp := byte(0), byte(0)
if (flags & 0x08) > 0 {
fxc = buff[dataOffset]
dataOffset++
}
if (flags & 0x10) > 0 {
fxp = buff[dataOffset]
dataOffset++
}
if fxc >= 0x40 {
fxc = 0
fxp = 0
}
pattern.data[patternDataOffset] = fxc
patternDataOffset++
pattern.data[patternDataOffset] = fxp
patternDataOffset++
}
}
dataOffset = nextOffset
}
instruments[0] = DefaultInstrument()
for insIdx := 1; insIdx <= numInstruments; insIdx++ {
instrument := &Instrument{}
instruments[insIdx] = instrument
instrument.name = string(buff[dataOffset+4 : dataOffset+4+22])
numSamples := int(binary.LittleEndian.Uint16(buff[dataOffset+27:]))
instrument.numSamples = numSamples
if numSamples > 0 {
instrument.samples = make([]*Sample, numSamples)
for keyIdx := uint32(0); keyIdx < 96; keyIdx++ {
instrument.keyToSample[keyIdx+1] = int(buff[dataOffset+33+keyIdx])
}
volEnv := &Envelope{}
instrument.volumeEnvelope = volEnv
volEnv.pointsTick = make([]int, 12)
volEnv.pointsAmpl = make([]int, 12)
pointTick := 0
for point := uint32(0); point < 12; point++ {
pointOffset := dataOffset + 129 + (point * 4)
pt := int(binary.LittleEndian.Uint16(buff[pointOffset:]))
volEnv.pointsTick[point] = pt
if deltaEnv {
volEnv.pointsTick[point] += pointTick
pointTick = pt
}
volEnv.pointsAmpl[point] = int(binary.LittleEndian.Uint16(buff[pointOffset+2:]))
}
panEnv := &Envelope{}
instrument.panningEnvelope = panEnv
panEnv.pointsTick = make([]int, 12)
panEnv.pointsAmpl = make([]int, 12)
pointTick = 0
for point := uint32(0); point < 12; point++ {
pointOffset := dataOffset + 177 + (point * 4)
pt := int(binary.LittleEndian.Uint16(buff[pointOffset:]))
panEnv.pointsTick[point] = pt
if deltaEnv {
panEnv.pointsTick[point] += pointTick
pointTick = pt
}
panEnv.pointsAmpl[point] = int(binary.LittleEndian.Uint16(buff[pointOffset+2:]))
}
volEnv.numPoints = int(buff[dataOffset+225])
if volEnv.numPoints > 12 {
volEnv.numPoints = 0
}
panEnv.numPoints = int(buff[dataOffset+226])
if panEnv.numPoints > 12 {
panEnv.numPoints = 0
}
volEnv.sustainTick = volEnv.pointsTick[buff[dataOffset+227]]
volEnv.loopStartTick = volEnv.pointsTick[buff[dataOffset+228]]
volEnv.loopEndTick = volEnv.pointsTick[buff[dataOffset+229]]
panEnv.sustainTick = panEnv.pointsTick[buff[dataOffset+230]]
panEnv.loopStartTick = panEnv.pointsTick[buff[dataOffset+231]]
panEnv.loopEndTick = panEnv.pointsTick[buff[dataOffset+232]]
volEnv.enabled = volEnv.numPoints > 0 && (buff[dataOffset+233]&0x1) > 0
volEnv.sustain = (buff[dataOffset+233] & 0x2) > 0
volEnv.looped = (buff[dataOffset+233] & 0x4) > 0
panEnv.enabled = panEnv.numPoints > 0 && (buff[dataOffset+234]&0x1) > 0
panEnv.sustain = (buff[dataOffset+234] & 0x2) > 0
panEnv.looped = (buff[dataOffset+234] & 0x4) > 0
instrument.vibratoType = int(buff[dataOffset+235])
instrument.vibratoSweep = int(buff[dataOffset+236])
instrument.vibratoDepth = int(buff[dataOffset+237])
instrument.vibratoRate = int(buff[dataOffset+238])
instrument.volumeFadeOut = int(binary.LittleEndian.Uint16((buff[dataOffset+239:])))
}
dataOffset += binary.LittleEndian.Uint32(buff[dataOffset:])
sampleHeaderOffset := dataOffset
dataOffset += uint32(numSamples) * 40
for samIdx := 0; samIdx < numSamples; samIdx++ {
sample := &Sample{}
instrument.samples[samIdx] = sample
sampleDataBytes := binary.LittleEndian.Uint32(buff[sampleHeaderOffset:])
sampleLoopStart := binary.LittleEndian.Uint32(buff[sampleHeaderOffset+4:])
sampleLoopLength := binary.LittleEndian.Uint32(buff[sampleHeaderOffset+8:])
sample.volume = int(int8(buff[sampleHeaderOffset+12]))
sample.fineTune = int(int8(buff[sampleHeaderOffset+13]))
sample.c2Rate = NTSC
looped := (buff[sampleHeaderOffset+14] & 0x3) > 0
pingPong := (buff[sampleHeaderOffset+14] & 0x2) > 0
sixteenBit := (buff[sampleHeaderOffset+14] & 0x10) > 0
sample.panning = int(buff[sampleHeaderOffset+15])
sample.relNote = int(int8(buff[sampleHeaderOffset+16]))
sample.name = string(buff[sampleHeaderOffset+18 : sampleHeaderOffset+18+22])
sampleHeaderOffset += 40
sampleDataLength := sampleDataBytes
if sixteenBit {
sampleDataLength /= 2
sampleLoopStart /= 2
sampleLoopLength /= 2
}
if !looped || (sampleLoopStart+sampleLoopLength) > sampleDataLength {
sampleLoopStart = sampleDataLength
sampleLoopLength = 0
}
sampleData := make([]int16, sampleDataLength)
if sixteenBit {
ampl := uint16(0)
for outIdx := uint32(0); outIdx < sampleDataLength; outIdx++ {
inIdx := dataOffset + outIdx*2
ampl += uint16(buff[inIdx])
ampl += uint16(buff[inIdx+1]) << 8
sampleData[outIdx] = int16(ampl)
}
} else {
ampl := byte(0)
for outIdx := uint32(0); outIdx < sampleDataLength; outIdx++ {
ampl += buff[dataOffset+outIdx]
sampleData[outIdx] = int16(uint16(ampl) << 8)
}
}
sample.setSampleData(sampleData, int(sampleLoopStart), int(sampleLoopLength), pingPong)
dataOffset += sampleDataBytes
}
}
return m, nil
}