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int48.go (994B)

      1 /*
      2  * Copyright 2021 ByteDance Inc.
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *     http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package rt
     18 
     19 const (
     20     MinInt48 = -(1 << 47)
     21     MaxInt48 = +(1 << 47) - 1
     22 )
     23 
     24 func PackInt(v int) uint64 {
     25     if u := uint64(v); v < MinInt48 || v > MaxInt48 {
     26         panic("int48 out of range")
     27     } else {
     28         return ((u >> 63) << 47) | (u & 0x00007fffffffffff)
     29     }
     30 }
     31 
     32 func UnpackInt(v uint64) int {
     33     v &= 0x0000ffffffffffff
     34     v |= (v >> 47) * (0xffff << 48)
     35     return int(v)
     36 }