aboutsummaryrefslogtreecommitdiffstats
path: root/core/utils.go
blob: 6b03f93828b325d0d3c553af7e7745d7c6a337bd (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
// Copyright 2018 The dexon-consensus-core Authors
// This file is part of the dexon-consensus-core library.
//
// The dexon-consensus-core library is free software: you can redistribute it
// and/or modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// The dexon-consensus-core library is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
// General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the dexon-consensus-core library. If not, see
// <http://www.gnu.org/licenses/>.

package core

import (
    "errors"
    "fmt"
    "os"
    "sort"
    "time"

    "github.com/dexon-foundation/dexon-consensus-core/common"
    "github.com/dexon-foundation/dexon-consensus-core/core/types"
)

var (
    debug = false
    // ErrEmptyTimestamps would be reported if Block.timestamps is empty.
    ErrEmptyTimestamps = errors.New("timestamp vector should not be empty")
)

func init() {
    if os.Getenv("DEBUG") != "" {
        debug = true
    }
}

// Debugf is like fmt.Printf, but only output when we are in debug mode.
func Debugf(format string, args ...interface{}) {
    if debug {
        fmt.Printf(format, args...)
    }
}

// Debugln is like fmt.Println, but only output when we are in debug mode.
func Debugln(args ...interface{}) {
    if debug {
        fmt.Println(args)
    }
}

func interpoTime(t1 time.Time, t2 time.Time, sep int) []time.Time {
    if sep == 0 {
        return []time.Time{}
    }
    if t1.After(t2) {
        return interpoTime(t2, t1, sep)
    }
    timestamps := make([]time.Time, sep)
    duration := t2.Sub(t1)
    period := time.Duration(
        (duration.Nanoseconds() / int64(sep+1))) * time.Nanosecond
    prevTime := t1
    for idx := range timestamps {
        prevTime = prevTime.Add(period)
        timestamps[idx] = prevTime
    }
    return timestamps
}
func getMedianTime(block *types.Block) (t time.Time, err error) {
    timestamps := []time.Time{}
    for _, timestamp := range block.Timestamps {
        timestamps = append(timestamps, timestamp)
    }
    if len(timestamps) == 0 {
        err = ErrEmptyTimestamps
        return
    }
    sort.Sort(common.ByTime(timestamps))
    if len(timestamps)%2 == 0 {
        t1 := timestamps[len(timestamps)/2-1]
        t2 := timestamps[len(timestamps)/2]
        t = interpoTime(t1, t2, 1)[0]
    } else {
        t = timestamps[len(timestamps)/2]
    }
    return

}

func removeFromSortedIntSlice(xs []int, x int) []int {
    indexToRemove := sort.Search(len(xs), func(idx int) bool {
        return xs[idx] >= x
    })
    if indexToRemove == len(xs) || xs[indexToRemove] != x {
        // This value is not found.
        return xs
    }
    return append(xs[:indexToRemove], xs[indexToRemove+1:]...)
}