kopia lustrzana https://github.com/jcs/id3-go
84 wiersze
1.7 KiB
Go
84 wiersze
1.7 KiB
Go
// Copyright 2013 Michael Yang. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package encodedbytes
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import (
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"io"
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)
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// Reader is a helper for Reading frame bytes
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type Reader struct {
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data []byte
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index int // current Reading index
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}
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func (r *Reader) Read(b []byte) (n int, err error) {
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if len(b) == 0 {
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return 0, nil
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}
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if r.index >= len(r.data) {
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return 0, io.EOF
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}
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n = copy(b, r.data[r.index:])
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r.index += n
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return
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}
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func (r *Reader) ReadByte() (b byte, err error) {
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if r.index >= len(r.data) {
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return 0, io.EOF
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}
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b = r.data[r.index]
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r.index++
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return
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}
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func (r *Reader) ReadNumBytes(n int) ([]byte, error) {
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if n <= 0 {
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return []byte{}, nil
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}
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if r.index+n > len(r.data) {
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return []byte{}, io.EOF
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}
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b := make([]byte, n)
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_, err := r.Read(b)
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return b, err
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}
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// Read a number of bytes and cast to a string
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func (r *Reader) ReadNumBytesString(n int) (string, error) {
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b, err := r.ReadNumBytes(n)
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return string(b), err
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}
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// Read until the end of the data
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func (r *Reader) ReadRest() ([]byte, error) {
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return r.ReadNumBytes(len(r.data) - r.index)
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}
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// Read until the end of the data and cast to a string
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func (r *Reader) ReadRestString(encoding byte) (string, error) {
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b, err := r.ReadRest()
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if err != nil {
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return "", err
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}
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return Decoders[encoding].ConvertString(string(b))
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}
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// Read a null terminated string of specified encoding
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func (r *Reader) ReadNullTermString(encoding byte) (string, error) {
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atIndex, afterIndex := nullIndex(r.data[r.index:], encoding)
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b, err := r.ReadNumBytes(afterIndex)
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if err != nil {
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return "", err
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}
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return Decoders[encoding].ConvertString(string(b[:atIndex]))
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}
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func NewReader(b []byte) *Reader { return &Reader{b, 0} }
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