mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-15 07:27:32 +01:00
82 lines
1.6 KiB
Go
82 lines
1.6 KiB
Go
// Copyright 2019 The Ebiten Authors
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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 vorbis
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import (
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"io"
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)
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type float32Reader interface {
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Read([]float32) (int, error)
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}
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func newInt16BytesReaderFromFloat32Reader(r float32Reader) io.Reader {
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return &int16BytesReader{r: r}
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}
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type int16BytesReader struct {
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r float32Reader
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eof bool
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hasRemain bool
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remain byte
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fbuf []float32
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}
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func (r *int16BytesReader) Read(buf []byte) (int, error) {
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if r.eof {
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return 0, io.EOF
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}
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if len(buf) == 0 {
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return 0, nil
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}
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if r.hasRemain {
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buf[0] = r.remain
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r.hasRemain = false
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return 1, nil
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}
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l := max(len(buf)/2, 1)
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if cap(r.fbuf) < l {
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r.fbuf = make([]float32, l)
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}
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n, err := r.r.Read(r.fbuf[:l])
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if err != nil && err != io.EOF {
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return 0, err
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}
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if err == io.EOF {
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r.eof = true
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}
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b := buf
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if len(buf) == 1 && n > 0 {
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b = make([]byte, 2)
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}
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for i := 0; i < n; i++ {
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f := r.fbuf[i]
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s := int16(f * (1<<15 - 1))
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b[2*i] = byte(s)
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b[2*i+1] = byte(s >> 8)
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}
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if len(buf) == 1 && len(b) == 2 {
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buf[0] = b[0]
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r.remain = b[1]
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r.hasRemain = true
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return 1, err
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}
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return n * 2, err
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}
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