mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 13:07:26 +01:00
135 lines
3.3 KiB
Go
135 lines
3.3 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
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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/exp/audio"
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)
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type Stream struct {
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src audio.ReadSeekCloser
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headerSize int64
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dataSize int64
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}
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func (s *Stream) Read(p []byte) (int, error) {
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return s.src.Read(p)
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}
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func (s *Stream) Seek(offset int64, whence int) (int64, error) {
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if whence == 0 {
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offset += s.headerSize
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}
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return s.src.Seek(offset, whence)
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}
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func (s *Stream) Close() error {
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return s.src.Close()
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}
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func (s *Stream) Size() int64 {
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return s.dataSize
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}
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func Decode(context *audio.Context, src audio.ReadSeekCloser) (*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(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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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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channelNum := int(buf[2]) | int(buf[3])<<8
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// TODO: Remove this magic number
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if channelNum != 2 {
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return nil, fmt.Errorf("wav: channel num must be 2")
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}
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bitsPerSample := int(buf[14]) | int(buf[15])<<8
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// TODO: Remove this magic number
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if bitsPerSample != 16 {
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return nil, fmt.Errorf("wav: bits per sample must be 16")
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}
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sampleRate := int64(buf[4]) | int64(buf[5])<<8 | int64(buf[6])<<16 | int64(buf[7]<<24)
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if int64(context.SampleRate()) != sampleRate {
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return nil, fmt.Errorf("wav: sample rate must be %d but %d", context.SampleRate(), 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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s := &Stream{
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src: src,
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headerSize: headerSize,
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dataSize: dataSize,
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}
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return s, nil
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}
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