/
reader.go
67 lines (58 loc) · 1.51 KB
/
reader.go
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// Copyright 2018 the u-root 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 uio
import (
"bytes"
"io"
"math"
"os"
"reflect"
)
type inMemReaderAt interface {
Bytes() []byte
}
// ReadAll reads everything that r contains.
//
// Callers *must* not modify bytes in the returned byte slice.
//
// If r is an in-memory representation, ReadAll will attempt to return a
// pointer to those bytes directly.
func ReadAll(r io.ReaderAt) ([]byte, error) {
if imra, ok := r.(inMemReaderAt); ok {
return imra.Bytes(), nil
}
return io.ReadAll(Reader(r))
}
// Reader generates a Reader from a ReaderAt.
func Reader(r io.ReaderAt) io.Reader {
return io.NewSectionReader(r, 0, math.MaxInt64)
}
// ReaderAtEqual compares the contents of r1 and r2.
func ReaderAtEqual(r1, r2 io.ReaderAt) bool {
var c, d []byte
var r1err, r2err error
if r1 != nil {
c, r1err = ReadAll(r1)
}
if r2 != nil {
d, r2err = ReadAll(r2)
}
return bytes.Equal(c, d) && reflect.DeepEqual(r1err, r2err)
}
// ReadIntoFile reads all from io.Reader into the file at given path.
//
// If the file at given path does not exist, a new file will be created.
// If the file exists at the given path, but not empty, it will be truncated.
func ReadIntoFile(r io.Reader, p string) error {
f, err := os.OpenFile(p, os.O_CREATE|os.O_RDWR|os.O_TRUNC, 0o644)
if err != nil {
return err
}
defer f.Close()
_, err = io.Copy(f, r)
if err != nil {
return err
}
return f.Close()
}