github.com/goshafaq/sonic@v0.0.0-20231026082336-871835fb94c6/internal/rt/int48.go (about)

     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 int64 = -(1 << 47)
    21  	MaxInt48 int64 = +(1 << 47) - 1
    22  )
    23  
    24  func PackInt(v int) uint64 {
    25  	if u := uint64(v); int64(v) < MinInt48 || int64(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  }