diff options
Diffstat (limited to 'vendor/github.com/couchbase/vellum/pack.go')
-rw-r--r-- | vendor/github.com/couchbase/vellum/pack.go | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/vendor/github.com/couchbase/vellum/pack.go b/vendor/github.com/couchbase/vellum/pack.go new file mode 100644 index 0000000000..78f3dcd588 --- /dev/null +++ b/vendor/github.com/couchbase/vellum/pack.go @@ -0,0 +1,55 @@ +// Copyright (c) 2017 Couchbase, 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 vellum + +func deltaAddr(base, trans uint64) uint64 { + // transition dest of 0 is special case + if trans == 0 { + return 0 + } + return base - trans +} + +const packOutMask = 1<<4 - 1 + +func encodePackSize(transSize, outSize int) byte { + var rv byte + rv = byte(transSize << 4) + rv |= byte(outSize) + return rv +} + +func decodePackSize(pack byte) (transSize int, packSize int) { + transSize = int(pack >> 4) + packSize = int(pack & packOutMask) + return +} + +const maxNumTrans = 1<<6 - 1 + +func encodeNumTrans(n int) byte { + if n <= maxNumTrans { + return byte(n) + } + return 0 +} + +func readPackedUint(data []byte) (rv uint64) { + for i := range data { + shifted := uint64(data[i]) << uint(i*8) + rv |= shifted + } + return +} |