iox

func Copy ¶

func Copy(dst io.Writer, src io.Reader) (written int64, err error)

Copy copies from src to dst until either EOF is reached on src or an error occurs. It returns the number of bytes copied and the first error encountered while copying, if any.

A successful Copy returns err == nil, not err == EOF. Because Copy is defined to read from src until EOF, it does not treat an EOF from Read as an error to be reported.

If src implements the WriterTo interface, the copy is implemented by calling src.WriteTo(dst). Otherwise, if dst implements the ReaderFrom interface, the copy is implemented by calling dst.ReadFrom(src).

func CopyBuffer ¶

func CopyBuffer(dst io.Writer, src io.Reader, buf []byte) (written int64, err error)

CopyBuffer is identical to Copy except that it stages through the provided buffer (if one is required) rather than allocating a temporary one. If buf is nil, one is allocated; otherwise if it has zero length, CopyBuffer panics.

If either src implements WriterTo or dst implements ReaderFrom, buf will not be used to perform the copy.

func CopyN ¶

func CopyN(dst io.Writer, src io.Reader, n int64) (written int64, err error)

CopyN copies n bytes (or until an error) from src to dst. It returns the number of bytes copied and the earliest error encountered while copying. On return, written == n if and only if err == nil.

If dst implements the ReaderFrom interface, the copy is implemented using it.

func Drain ¶

func Drain(r io.Reader)

Drain drain the reader

func DrainAndClose ¶

func DrainAndClose(r io.ReadCloser)

DrainAndClose drain and close the reader

func LimitWriter ¶ added in v1.0.12

func LimitWriter(w io.Writer, n int64) io.Writer

LimitWriter returns a Writer that writes limited bytes to the underlying writer. The underlying implementation is a *limitWriter.

func LineWriter ¶ added in v1.0.12

func LineWriter(w io.Writer, eol ...string) io.Writer

LineWriter return a eol append writer

func NewSectionReader ¶

func NewSectionReader(r io.ReaderAt, off int64, n int64) *io.SectionReader

NewSectionReader returns a SectionReader that reads from r starting at offset off and stops with EOF after n bytes.

func NopCloser ¶

func NopCloser(r io.Reader) io.ReadCloser

NopCloser returns a ReadCloser with a no-op Close method wrapping the provided Reader r.

func ReadAll ¶

func ReadAll(r io.Reader) ([]byte, error)

ReadAll reads from r until an error or EOF and returns the data it read. A successful call returns err == nil, not err == EOF. Because ReadAll is defined to read from src until EOF, it does not treat an EOF from Read as an error to be reported.

func ReadAtLeast ¶

func ReadAtLeast(r io.Reader, buf []byte, min int) (n int, err error)

ReadAtLeast reads from r into buf until it has read at least min bytes. It returns the number of bytes copied and an error if fewer bytes were read. The error is EOF only if no bytes were read. If an EOF happens after reading fewer than min bytes, ReadAtLeast returns ErrUnexpectedEOF. If min is greater than the length of buf, ReadAtLeast returns ErrShortBuffer. On return, n >= min if and only if err == nil. If r returns an error having read at least min bytes, the error is dropped.

func ReadFull ¶

func ReadFull(r io.Reader, buf []byte) (n int, err error)

ReadFull reads exactly len(buf) bytes from r into buf. It returns the number of bytes copied and an error if fewer bytes were read. The error is EOF only if no bytes were read. If an EOF happens after reading some but not all the bytes, ReadFull returns ErrUnexpectedEOF. On return, n == len(buf) if and only if err == nil. If r returns an error having read at least len(buf) bytes, the error is dropped.

func SkipBOM ¶

func SkipBOM(r io.Reader) (io.Reader, error)

SkipBOM skip bom and return a reader

func StripWriter ¶ added in v1.0.12

func StripWriter(w io.Writer) io.Writer

StripWriter return a string strip writer

func SyncWriter ¶

func SyncWriter(w io.Writer) io.Writer

SyncWriter return a synchronized writer

func TeeReader ¶

func TeeReader(r io.Reader, w io.Writer) io.Reader

TeeReader returns a Reader that writes to w what it reads from r. All reads from r performed through it are matched with corresponding writes to w. There is no internal buffering - the write must complete before the read completes. Any error encountered while writing is reported as a read error.

func WrapWriter ¶

func WrapWriter(w io.Writer, prefix, suffix string) io.Writer

WrapWriter return a prefix/suffix wrap writer

func WriteString ¶

func WriteString(w io.Writer, s string) (n int, err error)

WriteString writes the contents of the string s to w, which accepts a slice of bytes. If w implements StringWriter, its WriteString method is invoked directly. Otherwise, w.Write is called exactly once.