mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-12-27 20:28:54 +01:00
100 lines
2.0 KiB
Go
100 lines
2.0 KiB
Go
// Copyright 2017 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 convert
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import (
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"io"
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)
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type StereoI16 struct {
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source io.ReadSeeker
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mono bool
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eight bool
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buf []byte
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}
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func NewStereoI16(source io.ReadSeeker, mono, eight bool) *StereoI16 {
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return &StereoI16{
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source: source,
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mono: mono,
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eight: eight,
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}
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}
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func (s *StereoI16) Read(b []byte) (int, error) {
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l := len(b) / 4 * 4
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if s.mono {
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l /= 2
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}
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if s.eight {
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l /= 2
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}
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if cap(s.buf) < l {
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s.buf = make([]byte, l)
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}
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n, err := s.source.Read(s.buf[: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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switch {
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case s.mono && s.eight:
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for i := 0; i < n; i++ {
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v := int16(int(s.buf[i])*0x101 - (1 << 15))
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b[4*i] = byte(v)
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b[4*i+1] = byte(v >> 8)
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b[4*i+2] = byte(v)
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b[4*i+3] = byte(v >> 8)
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}
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case s.mono && !s.eight:
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for i := 0; i < n/2; i++ {
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b[4*i] = s.buf[2*i]
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b[4*i+1] = s.buf[2*i+1]
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b[4*i+2] = s.buf[2*i]
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b[4*i+3] = s.buf[2*i+1]
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}
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case !s.mono && s.eight:
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for i := 0; i < n/2; i++ {
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v0 := int16(int(s.buf[2*i])*0x101 - (1 << 15))
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v1 := int16(int(s.buf[2*i+1])*0x101 - (1 << 15))
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b[4*i] = byte(v0)
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b[4*i+1] = byte(v0 >> 8)
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b[4*i+2] = byte(v1)
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b[4*i+3] = byte(v1 >> 8)
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}
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default:
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copy(b[:n], s.buf[:n])
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}
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if s.mono {
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n *= 2
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}
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if s.eight {
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n *= 2
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}
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return n, err
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}
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func (s *StereoI16) Seek(offset int64, whence int) (int64, error) {
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offset = offset / 4 * 4
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if s.mono {
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offset /= 2
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}
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if s.eight {
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offset /= 2
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}
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return s.source.Seek(offset, whence)
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}
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