wrapio

Documentation

Index

• func Wrap(w DoerAt, p []byte, off int64, wrapAt int64) (n int, err error)
• type DoAtFunc
• type DoerAt
• type ReadWriterAt
• type WrapReader
  • func NewWrapReader(r io.ReaderAt, off int64, wrapAt int64) *WrapReader
  • func (w WrapReader) DoAt(p []byte, off int64) (n int, err error)
  • func (w WrapReader) Offset() int64
  • func (r *WrapReader) Read(p []byte) (n int, err error)
  • func (r *WrapReader) ReadAt(p []byte, off int64) (n int, err error)
  • func (w WrapReader) Seek(offset int64, whence int) (int64, error)
• type WrapWriter
  • func NewWrapWriter(w io.WriterAt, off int64, wrapAt int64) *WrapWriter
  • func (w WrapWriter) DoAt(p []byte, off int64) (n int, err error)
  • func (w WrapWriter) Offset() int64
  • func (w WrapWriter) Seek(offset int64, whence int) (int64, error)
  • func (w *WrapWriter) Write(p []byte) (n int, err error)
  • func (w *WrapWriter) WriteAt(p []byte, off int64) (n int, err error)
• type Wrapper
  • func NewWrapper(rwa ReadWriterAt, L, O, N int64) *Wrapper
  • func (wpr *Wrapper) Cap() int64
  • func (wpr *Wrapper) Len() int64
  • func (wpr *Wrapper) Read(p []byte) (n int, err error)
  • func (wpr *Wrapper) ReadAt(p []byte, off int64) (n int, err error)
  • func (wpr *Wrapper) Reset()
  • func (wpr *Wrapper) SetReadWriterAt(rwa ReadWriterAt)
  • func (wpr *Wrapper) Write(p []byte) (n int, err error)
  • func (wpr *Wrapper) WriteAt(p []byte, off int64) (n int, err error)

Functions

func Wrap

func Wrap(w DoerAt, p []byte, off int64, wrapAt int64) (n int, err error)

Wrap causes an action on an array of bytes (like read/write) to be done from an offset off, wrapping at offset wrapAt.

Types

type DoAtFunc

type DoAtFunc func([]byte, int64) (int, error)

DoAtFunc is implemented by ReadAt/WriteAt

type DoerAt

type DoerAt interface {
	DoAt([]byte, int64) (int, error)
}

DoerAt is a common interface for wrappers WriteAt or ReadAt functions

type ReadWriterAt

type ReadWriterAt interface {
	io.ReaderAt
	io.WriterAt
}

ReadWriterAt implements io.ReaderAt and io.WriterAt

type WrapReader

type WrapReader struct {
	// contains filtered or unexported fields
}

WrapReader wraps reads around a section of data.

func NewWrapReader

func NewWrapReader(r io.ReaderAt, off int64, wrapAt int64) *WrapReader

NewWrapReader creates a WrapReader starting at offset off, and wrapping at offset wrapAt.

func (WrapReader) DoAt

func (w WrapReader) DoAt(p []byte, off int64) (n int, err error)

func (WrapReader) Offset

func (w WrapReader) Offset() int64

func (*WrapReader) Read

func (r *WrapReader) Read(p []byte) (n int, err error)

Read reads into p starting at the current offset, wrapping if it reaches the end. The current offset is shifted forward by the amount read.

func (*WrapReader) ReadAt

func (r *WrapReader) ReadAt(p []byte, off int64) (n int, err error)

ReadAt reads into p starting at the current offset, wrapping when it reaches the end.

func (WrapReader) Seek

func (w WrapReader) Seek(offset int64, whence int) (int64, error)

type WrapWriter

type WrapWriter struct {
	// contains filtered or unexported fields
}

WrapWriter wraps writes around a section of data.

func NewWrapWriter

func NewWrapWriter(w io.WriterAt, off int64, wrapAt int64) *WrapWriter

NewWrapWriter creates a WrapWriter starting at offset off, and wrapping at offset wrapAt.

func (WrapWriter) DoAt

func (w WrapWriter) DoAt(p []byte, off int64) (n int, err error)

func (WrapWriter) Offset

func (w WrapWriter) Offset() int64

func (WrapWriter) Seek

func (w WrapWriter) Seek(offset int64, whence int) (int64, error)

func (*WrapWriter) Write

func (w *WrapWriter) Write(p []byte) (n int, err error)

Write writes p starting at the current offset, wrapping when it reaches the end. The current offset is shifted forward by the amount written.

func (*WrapWriter) WriteAt

func (w *WrapWriter) WriteAt(p []byte, off int64) (n int, err error)

WriteAt writes p starting at offset off, wrapping when it reaches the end.

type Wrapper

type Wrapper struct {
	// N is the offset at which to "wrap" back to the start
	N int64
	// L is the length of the data written
	L int64
	// O is our offset in the data
	O int64
	// contains filtered or unexported fields
}

Wrapper implements a io.ReadWriter and ReadWriterAt such that when reading/writing goes past N bytes, it "wraps" back to the beginning.

func NewWrapper

func NewWrapper(rwa ReadWriterAt, L, O, N int64) *Wrapper

NewWrapper creates a Wrapper based on ReadWriterAt rwa. L is the current length, O is the current offset, and N is offset at which we "wrap".

func (*Wrapper) Cap

func (wpr *Wrapper) Cap() int64

Cap returns the "wrap" offset (max # of bytes)

func (*Wrapper) Len

func (wpr *Wrapper) Len() int64

Len returns the # of bytes in the Wrapper

func (*Wrapper) Read

func (wpr *Wrapper) Read(p []byte) (n int, err error)

Read reads from the current offset into p, wrapping at Cap()

func (*Wrapper) ReadAt

func (wpr *Wrapper) ReadAt(p []byte, off int64) (n int, err error)

ReadAt reads from the current offset+off into p, wrapping at Cap()

func (*Wrapper) Reset

func (wpr *Wrapper) Reset()

Reset seeks to the start (0 offset), and sets the length to 0.

func (*Wrapper) SetReadWriterAt

func (wpr *Wrapper) SetReadWriterAt(rwa ReadWriterAt)

SetReadWriterAt lets you switch the underlying Read/WriterAt

func (*Wrapper) Write

func (wpr *Wrapper) Write(p []byte) (n int, err error)

Write writes p to the end of the Wrapper (at Len()), wrapping at Cap()

func (*Wrapper) WriteAt

func (wpr *Wrapper) WriteAt(p []byte, off int64) (n int, err error)

WriteAt writes p at the current offset+off, wrapping at Cap()