mirror of https://github.com/minio/minio.git
57 lines
2.0 KiB
Go
57 lines
2.0 KiB
Go
// Copyright (c) 2015-2023 MinIO, Inc.
|
|
//
|
|
// This file is part of MinIO Object Storage stack
|
|
//
|
|
// This program is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU Affero General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// This program is distributed in the hope that it will be useful
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU Affero General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU Affero General Public License
|
|
// along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
// Package ioutil implements some I/O utility functions which are not covered
|
|
// by the standard library.
|
|
package ioutil
|
|
|
|
import (
|
|
"errors"
|
|
"io"
|
|
)
|
|
|
|
// ErrOverread is returned to the reader when the hard limit of HardLimitReader is exceeded.
|
|
var ErrOverread = errors.New("input provided more bytes than specified")
|
|
|
|
// HardLimitReader returns a Reader that reads from r
|
|
// but returns an error if the source provides more data than allowed.
|
|
// This means the source *will* be overread unless EOF is returned prior.
|
|
// The underlying implementation is a *HardLimitedReader.
|
|
// This will ensure that at most n bytes are returned and EOF is reached.
|
|
func HardLimitReader(r io.Reader, n int64) io.Reader { return &HardLimitedReader{r, n} }
|
|
|
|
// A HardLimitedReader reads from R but limits the amount of
|
|
// data returned to just N bytes. Each call to Read
|
|
// updates N to reflect the new amount remaining.
|
|
// Read returns EOF when N <= 0 or when the underlying R returns EOF.
|
|
type HardLimitedReader struct {
|
|
R io.Reader // underlying reader
|
|
N int64 // max bytes remaining
|
|
}
|
|
|
|
func (l *HardLimitedReader) Read(p []byte) (n int, err error) {
|
|
if l.N < 0 {
|
|
return 0, ErrOverread
|
|
}
|
|
n, err = l.R.Read(p)
|
|
l.N -= int64(n)
|
|
if l.N < 0 {
|
|
return 0, ErrOverread
|
|
}
|
|
return
|
|
}
|