audio: Add InfiniteLoop (#291)

This commit is contained in:
Hajime Hoshi 2017-01-14 21:00:20 +09:00
parent c44ee9cde2
commit 9620c4efb2

74
audio/infiniteloop.go Normal file
View File

@ -0,0 +1,74 @@
// Copyright 2017 The Ebiten Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package audio
import (
"fmt"
"io"
)
// InfiniteLoop represents a loop which never ends.
type InfiniteLoop struct {
stream ReadSeekCloser
size int64
}
// NewInfiniteLoop creates a new infinite loop stream with a stream and size in bytes.
func NewInfiniteLoop(stream ReadSeekCloser, size int64) *InfiniteLoop {
return &InfiniteLoop{
stream: stream,
size: size,
}
}
// Read is implementation of ReadSeekCloser.
func (i *InfiniteLoop) Read(b []byte) (int, error) {
n, err := i.stream.Read(b)
if err == io.EOF {
if _, err := i.Seek(0, 0); err != nil {
return 0, err
}
err = nil
}
return n, err
}
// Seek is implementation of ReadSeekCloser.
func (i *InfiniteLoop) Seek(offset int64, whence int) (int64, error) {
next := int64(0)
switch whence {
case io.SeekStart:
next = offset
case io.SeekCurrent:
current, err := i.stream.Seek(0, io.SeekCurrent)
if err != nil {
return 0, err
}
next = current + offset
case io.SeekEnd:
return 0, fmt.Errorf("audio: whence must be 0 or 1 for InfiniteLoop")
}
next %= i.size
pos, err := i.stream.Seek(next, 0)
if err != nil {
return 0, err
}
return pos, nil
}
// Close is implementation of ReadSeekCloser.
func (l *InfiniteLoop) Close() error {
return l.stream.Close()
}