github.com/shaardie/u-root@v4.0.1-0.20190127173353-f24a1c26aa2e+incompatible/pkg/uio/reader.go (about)

     1  // Copyright 2018 the u-root Authors. All rights reserved
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package uio
     6  
     7  import (
     8  	"bytes"
     9  	"io"
    10  	"io/ioutil"
    11  	"math"
    12  )
    13  
    14  type inMemReaderAt interface {
    15  	Bytes() []byte
    16  }
    17  
    18  // ReadAll reads everything that r contains.
    19  //
    20  // Callers *must* not modify bytes in the returned byte slice.
    21  //
    22  // If r is an in-memory representation, ReadAll will attempt to return a
    23  // pointer to those bytes directly.
    24  func ReadAll(r io.ReaderAt) ([]byte, error) {
    25  	if imra, ok := r.(inMemReaderAt); ok {
    26  		return imra.Bytes(), nil
    27  	}
    28  	return ioutil.ReadAll(Reader(r))
    29  }
    30  
    31  // Reader generates a Reader from a ReaderAt.
    32  func Reader(r io.ReaderAt) io.Reader {
    33  	return io.NewSectionReader(r, 0, math.MaxInt64)
    34  }
    35  
    36  // ReaderAtEqual compares the contents of r1 and r2.
    37  func ReaderAtEqual(r1, r2 io.ReaderAt) bool {
    38  	var c, d []byte
    39  	var err error
    40  	if r1 != nil {
    41  		c, err = ReadAll(r1)
    42  		if err != nil {
    43  			return false
    44  		}
    45  	}
    46  
    47  	if r2 != nil {
    48  		d, err = ReadAll(r2)
    49  		if err != nil {
    50  			return false
    51  		}
    52  	}
    53  	return bytes.Equal(c, d)
    54  }