forked from FerretDB/FerretDB
/
string.go
83 lines (67 loc) · 1.93 KB
/
string.go
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// Copyright 2021 FerretDB Inc.
//
// 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 oldbson
import (
"bufio"
"bytes"
"encoding/binary"
"io"
"github.com/FerretDB/FerretDB/internal/util/lazyerrors"
)
// stringType represents BSON UTF-8 string type.
type stringType string
func (str *stringType) bsontype() {}
// ReadFrom implements bsontype interface.
func (str *stringType) ReadFrom(r *bufio.Reader) error {
var l int32
if err := binary.Read(r, binary.LittleEndian, &l); err != nil {
return lazyerrors.Error(err)
}
if l <= 0 {
return lazyerrors.Errorf("invalid length %d", l)
}
b := make([]byte, l)
if n, err := io.ReadFull(r, b); err != nil {
return lazyerrors.Errorf("expected %d, read %d: %w", len(b), n, err)
}
if b[l-1] != 0 {
return lazyerrors.Errorf("unexpected terminating byte %#02x", b[l-1])
}
*str = stringType(b[:l-1])
return nil
}
// WriteTo implements bsontype interface.
func (str stringType) WriteTo(w *bufio.Writer) error {
v, err := str.MarshalBinary()
if err != nil {
return lazyerrors.Error(err)
}
_, err = w.Write(v)
if err != nil {
return lazyerrors.Error(err)
}
return nil
}
// MarshalBinary implements bsontype interface.
func (str stringType) MarshalBinary() ([]byte, error) {
var buf bytes.Buffer
binary.Write(&buf, binary.LittleEndian, int32(len(str)+1))
buf.Write([]byte(str))
buf.WriteByte(0)
return buf.Bytes(), nil
}
// check interfaces
var (
_ bsontype = (*stringType)(nil)
)