subsonic-tui/vendor/github.com/hajimehoshi/go-mp3/source.go
Sagi Dayan 48661005be
initial commit
Signed-off-by: Sagi Dayan <sagidayan@gmail.com>
2024-09-01 16:30:56 +03:00

120 lines
2.4 KiB
Go

// Copyright 2017 Hajime Hoshi
//
// 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 mp3
import (
"errors"
"io"
)
type source struct {
reader io.Reader
buf []byte
pos int64
}
func (s *source) Seek(position int64, whence int) (int64, error) {
seeker, ok := s.reader.(io.Seeker)
if !ok {
return 0, errors.New("mp3: source must be io.Seeker")
}
s.buf = nil
n, err := seeker.Seek(position, whence)
if err != nil {
return 0, err
}
s.pos = n
return n, nil
}
func (s *source) skipTags() error {
buf := make([]byte, 3)
if _, err := s.ReadFull(buf); err != nil {
return err
}
switch string(buf) {
case "TAG":
buf := make([]byte, 125)
if _, err := s.ReadFull(buf); err != nil {
return err
}
case "ID3":
// Skip version (2 bytes) and flag (1 byte)
buf := make([]byte, 3)
if _, err := s.ReadFull(buf); err != nil {
return err
}
buf = make([]byte, 4)
n, err := s.ReadFull(buf)
if err != nil {
return err
}
if n != 4 {
return nil
}
size := (uint32(buf[0]) << 21) | (uint32(buf[1]) << 14) |
(uint32(buf[2]) << 7) | uint32(buf[3])
buf = make([]byte, size)
if _, err := s.ReadFull(buf); err != nil {
return err
}
default:
s.Unread(buf)
}
return nil
}
func (s *source) rewind() error {
if _, err := s.Seek(0, io.SeekStart); err != nil {
return err
}
s.pos = 0
s.buf = nil
return nil
}
func (s *source) Unread(buf []byte) {
s.buf = append(s.buf, buf...)
s.pos -= int64(len(buf))
}
func (s *source) ReadFull(buf []byte) (int, error) {
read := 0
if s.buf != nil {
read = copy(buf, s.buf)
if len(s.buf) > read {
s.buf = s.buf[read:]
} else {
s.buf = nil
}
if len(buf) == read {
return read, nil
}
}
n, err := io.ReadFull(s.reader, buf[read:])
if err != nil {
// Allow if all data can't be read. This is common.
if err == io.ErrUnexpectedEOF {
err = io.EOF
}
}
s.pos += int64(n)
return n + read, err
}