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encode_decode_uint32.go
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/
encode_decode_uint32.go
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// Copyright 2024 tobyzxj
//
// 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
//
// https://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 secoapcore
import (
"encoding/binary"
)
func EncodeUint32(buf []byte, value uint32) (int, error) {
switch {
case value == 0:
return 0, nil
case value <= max1ByteNumber:
if len(buf) < 1 {
return 1, ErrTooSmall
}
buf[0] = byte(value)
return 1, nil
case value <= max2ByteNumber:
if len(buf) < 2 {
return 2, ErrTooSmall
}
binary.BigEndian.PutUint16(buf, uint16(value))
return 2, nil
case value <= max3ByteNumber:
if len(buf) < 3 {
return 3, ErrTooSmall
}
rv := make([]byte, 4)
binary.BigEndian.PutUint32(rv, value)
copy(buf, rv[1:])
return 3, nil
default:
if len(buf) < 4 {
return 4, ErrTooSmall
}
binary.BigEndian.PutUint32(buf, value)
return 4, nil
}
}
func DecodeUint32(buf []byte) (uint32, int, error) {
if len(buf) > 4 {
buf = buf[:4]
}
tmp := []byte{0, 0, 0, 0}
copy(tmp[4-len(buf):], buf)
value := binary.BigEndian.Uint32(tmp)
return value, len(buf), nil
}