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55 lines
1.3 KiB
55 lines
1.3 KiB
// Copyright (c) 2017 Couchbase, Inc.
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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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package vellum
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func deltaAddr(base, trans uint64) uint64 {
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// transition dest of 0 is special case
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if trans == 0 {
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return 0
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}
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return base - trans
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}
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const packOutMask = 1<<4 - 1
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func encodePackSize(transSize, outSize int) byte {
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var rv byte
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rv = byte(transSize << 4)
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rv |= byte(outSize)
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return rv
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}
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func decodePackSize(pack byte) (transSize int, packSize int) {
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transSize = int(pack >> 4)
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packSize = int(pack & packOutMask)
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return
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}
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const maxNumTrans = 1<<6 - 1
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func encodeNumTrans(n int) byte {
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if n <= maxNumTrans {
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return byte(n)
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}
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return 0
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}
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func readPackedUint(data []byte) (rv uint64) {
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for i := range data {
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shifted := uint64(data[i]) << uint(i*8)
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rv |= shifted
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}
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return
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}
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