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- /*
- *
- * Copyright 2018 gRPC authors.
- *
- * 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 conn
-
- import (
- "errors"
- )
-
- const counterLen = 12
-
- var (
- errInvalidCounter = errors.New("invalid counter")
- )
-
- // Counter is a 96-bit, little-endian counter.
- type Counter struct {
- value [counterLen]byte
- invalid bool
- overflowLen int
- }
-
- // Value returns the current value of the counter as a byte slice.
- func (c *Counter) Value() ([]byte, error) {
- if c.invalid {
- return nil, errInvalidCounter
- }
- return c.value[:], nil
- }
-
- // Inc increments the counter and checks for overflow.
- func (c *Counter) Inc() {
- // If the counter is already invalid, there is no need to increase it.
- if c.invalid {
- return
- }
- i := 0
- for ; i < c.overflowLen; i++ {
- c.value[i]++
- if c.value[i] != 0 {
- break
- }
- }
- if i == c.overflowLen {
- c.invalid = true
- }
- }
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