readerutil - ActiveState ActiveGo 1.8

Package readerutil

import ""

Overview ▾

Package readerutil provides and operates on io.Readers.

Package readerutil contains io.Reader types.

func NewFakeSeeker

func NewFakeSeeker(r io.Reader, size int64) io.ReadSeeker

NewFakeSeeker returns a ReadSeeker that can pretend to Seek (based on the provided total size of the reader's content), but any reads will fail if the fake seek position doesn't match reality.

func NewStatsReadSeeker

func NewStatsReadSeeker(v *expvar.Int, rs io.ReadSeeker) io.ReadSeeker

NewReaderStats returns an io.ReadSeeker that will have the number of bytes read from rs added to v.

func NewStatsReader

func NewStatsReader(v *expvar.Int, r io.Reader) io.Reader

NewReaderStats returns an io.Reader that will have the number of bytes read from r added to v.



var (
    // r is the io.Reader we'd like to count read from.
    r  = strings.NewReader("Hello world")
    v  = expvar.NewInt("read-bytes")
    sw = NewStatsReader(v, r)
// Read from the wrapped io.Reader, StatReader will count the bytes.
io.Copy(ioutil.Discard, sw)
fmt.Printf("Read %s bytes\n", v.String())


Read 11 bytes

func Size

func Size(r io.Reader) (size int64, ok bool)

Size tries to determine the length of r. If r is an io.Seeker, Size may seek to guess the length.

type CountingReader

CountingReader wraps a Reader, incrementing N by the number of bytes read. No locking is performed.

type CountingReader struct {
    Reader io.Reader
    N      *int64

func (CountingReader) Read

func (cr CountingReader) Read(p []byte) (n int, err error)

type ReadSeekCloser

A ReadSeekCloser can Read, Seek, and Close.

type ReadSeekCloser interface {

type ReaderAtCloser

type ReaderAtCloser interface {

type SizeReaderAt

A SizeReaderAt is a ReaderAt with a Size method.

An io.SectionReader implements SizeReaderAt.

type SizeReaderAt interface {
    Size() int64

func NewMultiReaderAt

func NewMultiReaderAt(parts ...SizeReaderAt) SizeReaderAt

NewMultiReaderAt is like io.MultiReader but produces a ReaderAt (and Size), instead of just a reader.


Name Synopsis
singlereader package singlereader provides Open and Close operations, reusing existing file descriptors when possible.