minio/internal/s3select/csv/recordtransform.go

95 lines
2.1 KiB
Go

// Copyright (c) 2015-2021 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 csv
import (
"bytes"
"io"
)
// recordTransform will convert records to always have newline records.
type recordTransform struct {
reader io.Reader
// recordDelimiter can be up to 2 characters.
recordDelimiter []byte
oneByte []byte
useOneByte bool
}
func (rr *recordTransform) Read(p []byte) (n int, err error) {
if rr.useOneByte {
p[0] = rr.oneByte[0]
rr.useOneByte = false
n, err = rr.reader.Read(p[1:])
n++
} else {
n, err = rr.reader.Read(p)
}
if err != nil {
return n, err
}
// Do nothing if record-delimiter is already newline.
if string(rr.recordDelimiter) == "\n" {
return n, nil
}
// Change record delimiters to newline.
if len(rr.recordDelimiter) == 1 {
for idx := 0; idx < len(p); {
i := bytes.Index(p[idx:], rr.recordDelimiter)
if i < 0 {
break
}
idx += i
p[idx] = '\n'
}
return n, nil
}
// 2 characters...
for idx := 0; idx < len(p); {
i := bytes.Index(p[idx:], rr.recordDelimiter)
if i < 0 {
break
}
idx += i
p[idx] = '\n'
p = append(p[:idx+1], p[idx+2:]...)
n--
}
if p[n-1] != rr.recordDelimiter[0] {
return n, nil
}
if _, err = rr.reader.Read(rr.oneByte); err != nil {
return n, err
}
if rr.oneByte[0] == rr.recordDelimiter[1] {
p[n-1] = '\n'
return n, nil
}
rr.useOneByte = true
return n, nil
}