167 lines
3.4 KiB
Go
167 lines
3.4 KiB
Go
package internal
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import (
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"encoding/binary"
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"io"
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)
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// ByteInput typed interface around io.Reader or raw bytes
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type ByteInput interface {
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// Next returns a slice containing the next n bytes from the buffer,
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// advancing the buffer as if the bytes had been returned by Read.
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Next(n int) ([]byte, error)
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// ReadUInt32 reads uint32 with LittleEndian order
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ReadUInt32() (uint32, error)
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// ReadUInt16 reads uint16 with LittleEndian order
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ReadUInt16() (uint16, error)
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// GetReadBytes returns read bytes
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GetReadBytes() int64
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// SkipBytes skips exactly n bytes
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SkipBytes(n int) error
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}
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// NewByteInputFromReader creates reader wrapper
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func NewByteInputFromReader(reader io.Reader) ByteInput {
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return &ByteInputAdapter{
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r: reader,
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readBytes: 0,
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}
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}
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// NewByteInput creates raw bytes wrapper
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func NewByteInput(buf []byte) ByteInput {
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return &ByteBuffer{
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buf: buf,
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off: 0,
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}
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}
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// ByteBuffer raw bytes wrapper
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type ByteBuffer struct {
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buf []byte
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off int
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}
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// Next returns a slice containing the next n bytes from the reader
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// If there are fewer bytes than the given n, io.ErrUnexpectedEOF will be returned
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func (b *ByteBuffer) Next(n int) ([]byte, error) {
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m := len(b.buf) - b.off
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if n > m {
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return nil, io.ErrUnexpectedEOF
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}
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data := b.buf[b.off : b.off+n]
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b.off += n
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return data, nil
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}
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// ReadUInt32 reads uint32 with LittleEndian order
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func (b *ByteBuffer) ReadUInt32() (uint32, error) {
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if len(b.buf)-b.off < 4 {
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return 0, io.ErrUnexpectedEOF
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}
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v := binary.LittleEndian.Uint32(b.buf[b.off:])
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b.off += 4
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return v, nil
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}
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// ReadUInt16 reads uint16 with LittleEndian order
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func (b *ByteBuffer) ReadUInt16() (uint16, error) {
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if len(b.buf)-b.off < 2 {
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return 0, io.ErrUnexpectedEOF
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}
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v := binary.LittleEndian.Uint16(b.buf[b.off:])
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b.off += 2
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return v, nil
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}
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// GetReadBytes returns read bytes
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func (b *ByteBuffer) GetReadBytes() int64 {
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return int64(b.off)
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}
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// SkipBytes skips exactly n bytes
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func (b *ByteBuffer) SkipBytes(n int) error {
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m := len(b.buf) - b.off
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if n > m {
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return io.ErrUnexpectedEOF
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}
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b.off += n
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return nil
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}
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// Reset resets the given buffer with a new byte slice
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func (b *ByteBuffer) Reset(buf []byte) {
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b.buf = buf
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b.off = 0
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}
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// ByteInputAdapter reader wrapper
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type ByteInputAdapter struct {
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r io.Reader
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readBytes int
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}
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// Next returns a slice containing the next n bytes from the buffer,
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// advancing the buffer as if the bytes had been returned by Read.
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func (b *ByteInputAdapter) Next(n int) ([]byte, error) {
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buf := make([]byte, n)
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m, err := io.ReadAtLeast(b.r, buf, n)
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b.readBytes += m
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if err != nil {
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return nil, err
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}
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return buf, nil
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}
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// ReadUInt32 reads uint32 with LittleEndian order
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func (b *ByteInputAdapter) ReadUInt32() (uint32, error) {
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buf, err := b.Next(4)
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if err != nil {
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return 0, err
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}
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return binary.LittleEndian.Uint32(buf), nil
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}
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// ReadUInt16 reads uint16 with LittleEndian order
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func (b *ByteInputAdapter) ReadUInt16() (uint16, error) {
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buf, err := b.Next(2)
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if err != nil {
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return 0, err
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}
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return binary.LittleEndian.Uint16(buf), nil
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}
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// GetReadBytes returns read bytes
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func (b *ByteInputAdapter) GetReadBytes() int64 {
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return int64(b.readBytes)
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}
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// SkipBytes skips exactly n bytes
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func (b *ByteInputAdapter) SkipBytes(n int) error {
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_, err := b.Next(n)
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return err
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}
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// Reset resets the given buffer with a new stream
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func (b *ByteInputAdapter) Reset(stream io.Reader) {
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b.r = stream
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b.readBytes = 0
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}
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