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data-io.go
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data-io.go
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// Copyright 2023 Versity Software
// This file is licensed under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
package integration
import (
"crypto/rand"
"crypto/sha256"
"hash"
"io"
)
type RReader struct {
buf []byte
dataleft int
hash hash.Hash
}
func NewDataReader(totalsize, bufsize int) *RReader {
b := make([]byte, bufsize)
rand.Read(b)
return &RReader{
buf: b,
dataleft: totalsize,
hash: sha256.New(),
}
}
func (r *RReader) Read(p []byte) (int, error) {
n := min(len(p), len(r.buf), r.dataleft)
r.dataleft -= n
err := error(nil)
if n == 0 {
err = io.EOF
}
r.hash.Write(r.buf[:n])
return copy(p, r.buf[:n]), err
}
func (r *RReader) Sum() []byte {
return r.hash.Sum(nil)
}
type ZReader struct {
buf []byte
dataleft int
}
func NewZeroReader(totalsize, bufsize int) *ZReader {
b := make([]byte, bufsize)
return &ZReader{buf: b, dataleft: totalsize}
}
func (r *ZReader) Read(p []byte) (int, error) {
n := min(len(p), len(r.buf), r.dataleft)
r.dataleft -= n
err := error(nil)
if n == 0 {
err = io.EOF
}
return copy(p, r.buf[:n]), err
}
func min(values ...int) int {
if len(values) == 0 {
return 0
}
min := values[0]
for _, v := range values {
if v < min {
min = v
}
}
return min
}
type NW struct{}
func NewNullWriter() NW {
return NW{}
}
func (NW) WriteAt(p []byte, off int64) (n int, err error) {
return len(p), nil
}