github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/segment/test/set_functions.go (about)

     1  // Copyright 2018 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // Package segment is a test package.
    16  package segment
    17  
    18  type setFunctions struct{}
    19  
    20  // MinKey returns the minimum key for the set.
    21  func (s setFunctions) MinKey() int {
    22  	return -s.MaxKey() - 1
    23  }
    24  
    25  // MaxKey returns the maximum key for the set.
    26  func (setFunctions) MaxKey() int {
    27  	return int(^uint(0) >> 1)
    28  }
    29  
    30  func (setFunctions) ClearValue(*int) {}
    31  
    32  func (setFunctions) Merge(_ Range, val1 int, _ Range, _ int) (int, bool) {
    33  	return val1, true
    34  }
    35  
    36  func (setFunctions) Split(_ Range, val int, _ int) (int, int) {
    37  	return val, val
    38  }
    39  
    40  type gapSetFunctions struct {
    41  	setFunctions
    42  }
    43  
    44  // MinKey is adjusted to make sure no add overflow would happen in test cases.
    45  // e.g. A gap with range {MinInt32, 2} would cause overflow in Range().Length().
    46  //
    47  // Normally Keys should be unsigned to avoid these issues.
    48  func (s gapSetFunctions) MinKey() int {
    49  	return s.setFunctions.MinKey() / 2
    50  }
    51  
    52  // MaxKey returns the maximum key for the set.
    53  func (s gapSetFunctions) MaxKey() int {
    54  	return s.setFunctions.MaxKey() / 2
    55  }