mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-12-25 19:28:57 +01:00
267 lines
7.3 KiB
Go
267 lines
7.3 KiB
Go
// Copyright 2016 Hajime Hoshi
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package wav provides WAV (RIFF) decoder.
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package wav
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import (
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"bytes"
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"fmt"
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"io"
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"github.com/hajimehoshi/ebiten/v2/audio"
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"github.com/hajimehoshi/ebiten/v2/audio/internal/convert"
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)
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// Stream is a decoded audio stream.
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type Stream struct {
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inner io.ReadSeeker
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size int64
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}
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// Read is implementation of io.Reader's Read.
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func (s *Stream) Read(p []byte) (int, error) {
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return s.inner.Read(p)
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}
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// Seek is implementation of io.Seeker's Seek.
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//
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// Note that Seek can take long since decoding is a relatively heavy task.
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//
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// If the underlying source is not an io.Seeker, Seek panics.
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func (s *Stream) Seek(offset int64, whence int) (int64, error) {
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return s.inner.Seek(offset, whence)
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}
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// Length returns the size of decoded stream in bytes.
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func (s *Stream) Length() int64 {
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return s.size
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}
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type stream struct {
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src io.Reader
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headerSize int64
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dataSize int64
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remaining int64
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}
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// Read is implementation of io.Reader's Read.
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func (s *stream) Read(p []byte) (int, error) {
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if s.remaining <= 0 {
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return 0, io.EOF
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}
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if s.remaining < int64(len(p)) {
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p = p[0:s.remaining]
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}
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n, err := s.src.Read(p)
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s.remaining -= int64(n)
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return n, err
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}
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// Seek is implementation of io.Seeker's Seek.
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//
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// If the underlying source is not an io.Seeker, Seek panics.
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func (s *stream) Seek(offset int64, whence int) (int64, error) {
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seeker, ok := s.src.(io.Seeker)
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if !ok {
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panic("wav: s.src must be io.Seeker but not")
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}
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switch whence {
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case io.SeekStart:
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offset = offset + s.headerSize
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case io.SeekCurrent:
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case io.SeekEnd:
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offset = s.headerSize + s.dataSize + offset
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whence = io.SeekStart
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}
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n, err := seeker.Seek(offset, whence)
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if err != nil {
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return 0, err
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}
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if n-s.headerSize < 0 {
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return 0, fmt.Errorf("wav: invalid offset")
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}
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s.remaining = s.dataSize - (n - s.headerSize)
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// There could be a tail in wav file.
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if s.remaining < 0 {
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s.remaining = 0
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return s.dataSize, nil
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}
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return n - s.headerSize, nil
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}
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// DecodeWithSampleRate decodes WAV (RIFF) data to playable stream.
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//
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// The format must be 1 or 2 channels, 8bit or 16bit little endian PCM.
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// The format is converted into 2 channels and 16bit.
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//
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// DecodeWithSampleRate returns error when decoding fails or IO error happens.
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//
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// The returned Stream's Seek is available only when src is an io.Seeker.
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//
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// A Stream doesn't close src even if src implements io.Closer.
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// Closing the source is src owner's responsibility.
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func DecodeWithoutResampling(src io.Reader) (*Stream, error) {
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return decode(src, nil)
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}
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// DecodeWithSampleRate decodes WAV (RIFF) data to playable stream.
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//
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// The format must be 1 or 2 channels, 8bit or 16bit little endian PCM.
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// The format is converted into 2 channels and 16bit.
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//
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// DecodeWithSampleRate returns error when decoding fails or IO error happens.
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//
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// DecodeWithSampleRate automatically resamples the stream to fit with sampleRate if necessary.
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//
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// The returned Stream's Seek is available only when src is an io.Seeker.
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//
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// A Stream doesn't close src even if src implements io.Closer.
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// Closing the source is src owner's responsibility.
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func DecodeWithSampleRate(sampleRate int, src io.Reader) (*Stream, error) {
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return decode(src, &sampleRate)
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}
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func decode(src io.Reader, sampleRate *int) (*Stream, error) {
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buf := make([]byte, 12)
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n, err := io.ReadFull(src, buf)
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if n != len(buf) {
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return nil, fmt.Errorf("wav: invalid header")
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}
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if err != nil {
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return nil, err
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}
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if !bytes.Equal(buf[0:4], []byte("RIFF")) {
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return nil, fmt.Errorf("wav: invalid header: 'RIFF' not found")
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}
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if !bytes.Equal(buf[8:12], []byte("WAVE")) {
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return nil, fmt.Errorf("wav: invalid header: 'WAVE' not found")
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}
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// Read chunks
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dataSize := int64(0)
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headerSize := int64(len(buf))
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sampleRateFrom := 0
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sampleRateTo := 0
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mono := false
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bitsPerSample := 0
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chunks:
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for {
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buf := make([]byte, 8)
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n, err := io.ReadFull(src, buf)
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if n != len(buf) {
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return nil, fmt.Errorf("wav: invalid header")
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}
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if err != nil {
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return nil, err
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}
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headerSize += 8
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size := int64(buf[4]) | int64(buf[5])<<8 | int64(buf[6])<<16 | int64(buf[7])<<24
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switch {
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case bytes.Equal(buf[0:4], []byte("fmt ")):
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// Size of 'fmt' header is usually 16, but can be more than 16.
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if size < 16 {
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return nil, fmt.Errorf("wav: invalid header: maybe non-PCM file?")
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}
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buf := make([]byte, size)
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n, err := io.ReadFull(src, buf)
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if n != len(buf) {
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return nil, fmt.Errorf("wav: invalid header")
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}
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if err != nil {
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return nil, err
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}
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format := int(buf[0]) | int(buf[1])<<8
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if format != 1 {
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return nil, fmt.Errorf("wav: format must be linear PCM")
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}
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channelCount := int(buf[2]) | int(buf[3])<<8
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switch channelCount {
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case 1:
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mono = true
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case 2:
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mono = false
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default:
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return nil, fmt.Errorf("wav: number of channels must be 1 or 2 but was %d", channelCount)
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}
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bitsPerSample = int(buf[14]) | int(buf[15])<<8
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if bitsPerSample != 8 && bitsPerSample != 16 {
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return nil, fmt.Errorf("wav: bits per sample must be 8 or 16 but was %d", bitsPerSample)
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}
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origSampleRate := int64(buf[4]) | int64(buf[5])<<8 | int64(buf[6])<<16 | int64(buf[7])<<24
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if sampleRate != nil && int64(*sampleRate) != origSampleRate {
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sampleRateFrom = int(origSampleRate)
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sampleRateTo = *sampleRate
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}
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headerSize += size
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case bytes.Equal(buf[0:4], []byte("data")):
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dataSize = size
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break chunks
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default:
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buf := make([]byte, size)
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n, err := io.ReadFull(src, buf)
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if n != len(buf) {
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return nil, fmt.Errorf("wav: invalid header")
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}
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if err != nil {
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return nil, err
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}
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headerSize += size
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}
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}
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var s io.ReadSeeker = &stream{
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src: src,
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headerSize: headerSize,
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dataSize: dataSize,
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remaining: dataSize,
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}
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if mono || bitsPerSample != 16 {
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s = convert.NewStereo16(s, mono, bitsPerSample != 16)
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if mono {
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dataSize *= 2
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}
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if bitsPerSample != 16 {
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dataSize *= 2
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}
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}
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if sampleRateFrom != sampleRateTo {
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r := convert.NewResampling(s, dataSize, sampleRateFrom, sampleRateTo)
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s = r
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dataSize = r.Length()
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}
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ss := &Stream{inner: s, size: dataSize}
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return ss, nil
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}
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// Decode decodes WAV (RIFF) data to playable stream.
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//
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// The format must be 1 or 2 channels, 8bit or 16bit little endian PCM.
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// The format is converted into 2 channels and 16bit.
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//
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// Decode returns error when decoding fails or IO error happens.
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//
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// Decode automatically resamples the stream to fit with the audio context if necessary.
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//
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// The returned Stream's Seek is available only when src is an io.Seeker.
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//
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// A Stream doesn't close src even if src implements io.Closer.
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// Closing the source is src owner's responsibility.
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//
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// Deprecated: as of v2.1. Use DecodeWithSampleRate instead.
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func Decode(context *audio.Context, src io.Reader) (*Stream, error) {
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return DecodeWithSampleRate(context.SampleRate(), src)
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}
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