a geicko-2 based round robin ranking system designed to test c++ battleship submissions battleship.dunkirk.sh
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1// Copyright 2022 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5package slog 6 7import ( 8 "errors" 9 "fmt" 10 "strconv" 11 "strings" 12 "sync/atomic" 13) 14 15// A Level is the importance or severity of a log event. 16// The higher the level, the more important or severe the event. 17type Level int 18 19// Level numbers are inherently arbitrary, 20// but we picked them to satisfy three constraints. 21// Any system can map them to another numbering scheme if it wishes. 22// 23// First, we wanted the default level to be Info, Since Levels are ints, Info is 24// the default value for int, zero. 25// 26 27// Second, we wanted to make it easy to use levels to specify logger verbosity. 28// Since a larger level means a more severe event, a logger that accepts events 29// with smaller (or more negative) level means a more verbose logger. Logger 30// verbosity is thus the negation of event severity, and the default verbosity 31// of 0 accepts all events at least as severe as INFO. 32// 33// Third, we wanted some room between levels to accommodate schemes with named 34// levels between ours. For example, Google Cloud Logging defines a Notice level 35// between Info and Warn. Since there are only a few of these intermediate 36// levels, the gap between the numbers need not be large. Our gap of 4 matches 37// OpenTelemetry's mapping. Subtracting 9 from an OpenTelemetry level in the 38// DEBUG, INFO, WARN and ERROR ranges converts it to the corresponding slog 39// Level range. OpenTelemetry also has the names TRACE and FATAL, which slog 40// does not. But those OpenTelemetry levels can still be represented as slog 41// Levels by using the appropriate integers. 42// 43// Names for common levels. 44const ( 45 LevelDebug Level = -4 46 LevelInfo Level = 0 47 LevelWarn Level = 4 48 LevelError Level = 8 49) 50 51// String returns a name for the level. 52// If the level has a name, then that name 53// in uppercase is returned. 54// If the level is between named values, then 55// an integer is appended to the uppercased name. 56// Examples: 57// 58// LevelWarn.String() => "WARN" 59// (LevelInfo+2).String() => "INFO+2" 60func (l Level) String() string { 61 str := func(base string, val Level) string { 62 if val == 0 { 63 return base 64 } 65 return fmt.Sprintf("%s%+d", base, val) 66 } 67 68 switch { 69 case l < LevelInfo: 70 return str("DEBUG", l-LevelDebug) 71 case l < LevelWarn: 72 return str("INFO", l-LevelInfo) 73 case l < LevelError: 74 return str("WARN", l-LevelWarn) 75 default: 76 return str("ERROR", l-LevelError) 77 } 78} 79 80// MarshalJSON implements [encoding/json.Marshaler] 81// by quoting the output of [Level.String]. 82func (l Level) MarshalJSON() ([]byte, error) { 83 // AppendQuote is sufficient for JSON-encoding all Level strings. 84 // They don't contain any runes that would produce invalid JSON 85 // when escaped. 86 return strconv.AppendQuote(nil, l.String()), nil 87} 88 89// UnmarshalJSON implements [encoding/json.Unmarshaler] 90// It accepts any string produced by [Level.MarshalJSON], 91// ignoring case. 92// It also accepts numeric offsets that would result in a different string on 93// output. For example, "Error-8" would marshal as "INFO". 94func (l *Level) UnmarshalJSON(data []byte) error { 95 s, err := strconv.Unquote(string(data)) 96 if err != nil { 97 return err 98 } 99 return l.parse(s) 100} 101 102// MarshalText implements [encoding.TextMarshaler] 103// by calling [Level.String]. 104func (l Level) MarshalText() ([]byte, error) { 105 return []byte(l.String()), nil 106} 107 108// UnmarshalText implements [encoding.TextUnmarshaler]. 109// It accepts any string produced by [Level.MarshalText], 110// ignoring case. 111// It also accepts numeric offsets that would result in a different string on 112// output. For example, "Error-8" would marshal as "INFO". 113func (l *Level) UnmarshalText(data []byte) error { 114 return l.parse(string(data)) 115} 116 117func (l *Level) parse(s string) (err error) { 118 defer func() { 119 if err != nil { 120 err = fmt.Errorf("slog: level string %q: %w", s, err) 121 } 122 }() 123 124 name := s 125 offset := 0 126 if i := strings.IndexAny(s, "+-"); i >= 0 { 127 name = s[:i] 128 offset, err = strconv.Atoi(s[i:]) 129 if err != nil { 130 return err 131 } 132 } 133 switch strings.ToUpper(name) { 134 case "DEBUG": 135 *l = LevelDebug 136 case "INFO": 137 *l = LevelInfo 138 case "WARN": 139 *l = LevelWarn 140 case "ERROR": 141 *l = LevelError 142 default: 143 return errors.New("unknown name") 144 } 145 *l += Level(offset) 146 return nil 147} 148 149// Level returns the receiver. 150// It implements Leveler. 151func (l Level) Level() Level { return l } 152 153// A LevelVar is a Level variable, to allow a Handler level to change 154// dynamically. 155// It implements Leveler as well as a Set method, 156// and it is safe for use by multiple goroutines. 157// The zero LevelVar corresponds to LevelInfo. 158type LevelVar struct { 159 val atomic.Int64 160} 161 162// Level returns v's level. 163func (v *LevelVar) Level() Level { 164 return Level(int(v.val.Load())) 165} 166 167// Set sets v's level to l. 168func (v *LevelVar) Set(l Level) { 169 v.val.Store(int64(l)) 170} 171 172func (v *LevelVar) String() string { 173 return fmt.Sprintf("LevelVar(%s)", v.Level()) 174} 175 176// MarshalText implements [encoding.TextMarshaler] 177// by calling [Level.MarshalText]. 178func (v *LevelVar) MarshalText() ([]byte, error) { 179 return v.Level().MarshalText() 180} 181 182// UnmarshalText implements [encoding.TextUnmarshaler] 183// by calling [Level.UnmarshalText]. 184func (v *LevelVar) UnmarshalText(data []byte) error { 185 var l Level 186 if err := l.UnmarshalText(data); err != nil { 187 return err 188 } 189 v.Set(l) 190 return nil 191} 192 193// A Leveler provides a Level value. 194// 195// As Level itself implements Leveler, clients typically supply 196// a Level value wherever a Leveler is needed, such as in HandlerOptions. 197// Clients who need to vary the level dynamically can provide a more complex 198// Leveler implementation such as *LevelVar. 199type Leveler interface { 200 Level() Level 201}