...
Run Format

Source file src/cmd/internal/bio/buf.go

Documentation: cmd/internal/bio

  // Copyright 2015 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  // Package bio implements common I/O abstractions used within the Go toolchain.
  package bio
  
  import (
  	"bufio"
  	"log"
  	"os"
  )
  
  // Reader implements a seekable buffered io.Reader.
  type Reader struct {
  	f *os.File
  	*bufio.Reader
  }
  
  // Writer implements a seekable buffered io.Writer.
  type Writer struct {
  	f *os.File
  	*bufio.Writer
  }
  
  // Create creates the file named name and returns a Writer
  // for that file.
  func Create(name string) (*Writer, error) {
  	f, err := os.Create(name)
  	if err != nil {
  		return nil, err
  	}
  	return &Writer{f: f, Writer: bufio.NewWriter(f)}, nil
  }
  
  // Open returns a Reader for the file named name.
  func Open(name string) (*Reader, error) {
  	f, err := os.Open(name)
  	if err != nil {
  		return nil, err
  	}
  	return &Reader{f: f, Reader: bufio.NewReader(f)}, nil
  }
  
  func (r *Reader) Seek(offset int64, whence int) int64 {
  	if whence == 1 {
  		offset -= int64(r.Buffered())
  	}
  	off, err := r.f.Seek(offset, whence)
  	if err != nil {
  		log.Fatalf("seeking in output: %v", err)
  	}
  	r.Reset(r.f)
  	return off
  }
  
  func (w *Writer) Seek(offset int64, whence int) int64 {
  	if err := w.Flush(); err != nil {
  		log.Fatalf("writing output: %v", err)
  	}
  	off, err := w.f.Seek(offset, whence)
  	if err != nil {
  		log.Fatalf("seeking in output: %v", err)
  	}
  	return off
  }
  
  func (r *Reader) Offset() int64 {
  	off, err := r.f.Seek(0, 1)
  	if err != nil {
  		log.Fatalf("seeking in output [0, 1]: %v", err)
  	}
  	off -= int64(r.Buffered())
  	return off
  }
  
  func (w *Writer) Offset() int64 {
  	if err := w.Flush(); err != nil {
  		log.Fatalf("writing output: %v", err)
  	}
  	off, err := w.f.Seek(0, 1)
  	if err != nil {
  		log.Fatalf("seeking in output [0, 1]: %v", err)
  	}
  	return off
  }
  
  func (r *Reader) Close() error {
  	return r.f.Close()
  }
  
  func (w *Writer) Close() error {
  	err := w.Flush()
  	err1 := w.f.Close()
  	if err == nil {
  		err = err1
  	}
  	return err
  }
  

View as plain text