Package readerutil

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 {
    io.Reader
    io.Seeker
    io.Closer
}

type ReaderAtCloser ¶

type ReaderAtCloser interface {
    io.ReaderAt
    io.Closer
}

type SizeReaderAt ¶

A SizeReaderAt is a ReaderAt with a Size method.

An io.SectionReader implements SizeReaderAt.

type SizeReaderAt interface {
    Size() int64
    io.ReaderAt
}

func NewMultiReaderAt ¶

func NewMultiReaderAt(parts ...SizeReaderAt) SizeReaderAt

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

Subdirectories