mirror of https://github.com/grpc/grpc-go.git
49 lines
1.4 KiB
Go
49 lines
1.4 KiB
Go
/*
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*
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* Copyright 2018 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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package conn
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import (
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"errors"
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)
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const (
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// GcmTagSize is the GCM tag size is the difference in length between
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// plaintext and ciphertext. From crypto/cipher/gcm.go in Go crypto
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// library.
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GcmTagSize = 16
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)
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// ErrAuth occurs on authentication failure.
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var ErrAuth = errors.New("message authentication failed")
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// SliceForAppend takes a slice and a requested number of bytes. It returns a
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// slice with the contents of the given slice followed by that many bytes and a
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// second slice that aliases into it and contains only the extra bytes. If the
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// original slice has sufficient capacity then no allocation is performed.
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func SliceForAppend(in []byte, n int) (head, tail []byte) {
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if total := len(in) + n; cap(in) >= total {
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head = in[:total]
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} else {
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head = make([]byte, total)
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copy(head, in)
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}
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tail = head[len(in):]
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return head, tail
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}
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