Go标准库之io

发表于

常量

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io.EOF 根据reader接口说明，在n>0且数据被读完的情况下，当次返回的error有可能是EOF也有可能是nil
SeekStart   = 0 // seek relative to the origin of the file
SeekCurrent = 1 // seek relative to the current offset
SeekEnd     = 2 // seek relative to the end

接口

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type Reader interface {
Read(p []byte) (n int, err error)
}
对于一个可读对象通常需要实现Reader接口
type Writer interface {
Write(p []byte) (n int, err error)
}
可写
type ReaderAt interface {
ReadAt(p []byte, off int64) (n int, err error)
}
从off处开始读len(p)个字节
type WriterAt interface {
WriteAt(p []byte, off int64) (n int, err error)
}
从off处开始写len(p)个字节
type ReaderFrom interface {
ReadFrom(r Reader) (n int64, err error)
}
type WriterTo interface {
WriteTo(w Writer) (n int64, err error)
}
结合ReaderFrom和WriterTo 我们可以做到"一次性从某个地方读取或写到某个地方去"
type Seeker interface {
Seek(offset int64, whence int) (ret int64, err error)
}
Seeker设置下次write或read的偏移量为offset,whence:0标识相对文件起点处，1标识相对文件当前偏移量，2现对于文件结尾处，Seek返回新的偏移量和错误
type Closer interface {
Close() error
}
用于关闭数据流
type ByteReader interface {
ReadByte() (c byte, err error)
}
type ByteWriter interface {
WriteByte(c byte) error
}
按字节读取或写入，这两个接口在二进制数据或归档压缩时用的比较多
ByteScanner
RuneReader
RuneScanner
组合接口    
  ReadCloser
  ReadSeeker
  ReadWriteCloser
  ReadWriteSeeker
  ReadWriter
  WriteCloser
  WriteSeeker