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| 1 | +package parsercommon |
| 2 | + |
| 3 | +import ( |
| 4 | + "fmt" |
| 5 | + "strconv" |
| 6 | + "strings" |
| 7 | +) |
| 8 | + |
| 9 | +const ( |
| 10 | + NO_VERSION = -1 |
| 11 | +) |
| 12 | + |
| 13 | +var ( |
| 14 | + ErrEOL = &ParserError{"End of log line"} |
| 15 | + ErrNoSpace = &ParserError{"No space found"} |
| 16 | + |
| 17 | + ErrPriorityNoStart = &ParserError{"No start char found for priority"} |
| 18 | + ErrPriorityEmpty = &ParserError{"Priority field empty"} |
| 19 | + ErrPriorityNoEnd = &ParserError{"No end char found for priority"} |
| 20 | + ErrPriorityTooShort = &ParserError{"Priority field too short"} |
| 21 | + ErrPriorityTooLong = &ParserError{"Priority field too long"} |
| 22 | + ErrPriorityNonDigit = &ParserError{"Non digit found in priority"} |
| 23 | + |
| 24 | + ErrVersionNotFound = &ParserError{"Can not find version"} |
| 25 | + |
| 26 | + ErrTimestampUnknownFormat = &ParserError{"Timestamp format unknown"} |
| 27 | + |
| 28 | + ErrHostnameNotFound = &ParserError{"Hostname not found"} |
| 29 | +) |
| 30 | + |
| 31 | +type ParserError struct { |
| 32 | + ErrorString string |
| 33 | +} |
| 34 | + |
| 35 | +type Priority struct { |
| 36 | + P int |
| 37 | + F Facility |
| 38 | + S Severity |
| 39 | +} |
| 40 | + |
| 41 | +type Facility struct { |
| 42 | + Value int |
| 43 | +} |
| 44 | + |
| 45 | +type Severity struct { |
| 46 | + Value int |
| 47 | +} |
| 48 | + |
| 49 | +// https://tools.ietf.org/html/rfc3164#section-4.1 |
| 50 | +func ParsePriority(buff []byte, cursor *int, l int) (*Priority, error) { |
| 51 | + if l <= 0 { |
| 52 | + return nil, ErrPriorityEmpty |
| 53 | + } |
| 54 | + |
| 55 | + if buff[*cursor] != '<' { |
| 56 | + return nil, ErrPriorityNoStart |
| 57 | + } |
| 58 | + |
| 59 | + i := 1 |
| 60 | + priDigit := 0 |
| 61 | + |
| 62 | + for i < l { |
| 63 | + if i >= 5 { |
| 64 | + return nil, ErrPriorityTooLong |
| 65 | + } |
| 66 | + |
| 67 | + c := buff[i] |
| 68 | + |
| 69 | + if c == '>' { |
| 70 | + if i == 1 { |
| 71 | + return nil, ErrPriorityTooShort |
| 72 | + } |
| 73 | + |
| 74 | + *cursor = i + 1 |
| 75 | + |
| 76 | + return NewPriority(priDigit), nil |
| 77 | + } |
| 78 | + |
| 79 | + if IsDigit(c) { |
| 80 | + v, e := strconv.Atoi(string(c)) |
| 81 | + if e != nil { |
| 82 | + return nil, e |
| 83 | + } |
| 84 | + |
| 85 | + priDigit = (priDigit * 10) + v |
| 86 | + } else { |
| 87 | + return nil, ErrPriorityNonDigit |
| 88 | + } |
| 89 | + |
| 90 | + i++ |
| 91 | + } |
| 92 | + |
| 93 | + return nil, ErrPriorityNoEnd |
| 94 | +} |
| 95 | + |
| 96 | +// https://tools.ietf.org/html/rfc5424#section-6.2.2 |
| 97 | +func ParseVersion(buff []byte, cursor *int, l int) (int, error) { |
| 98 | + if *cursor >= l { |
| 99 | + return NO_VERSION, ErrVersionNotFound |
| 100 | + } |
| 101 | + |
| 102 | + c := buff[*cursor] |
| 103 | + *cursor++ |
| 104 | + |
| 105 | + // XXX : not a version, not an error though as RFC 3164 does not support it |
| 106 | + if !IsDigit(c) { |
| 107 | + return NO_VERSION, nil |
| 108 | + } |
| 109 | + |
| 110 | + v, e := strconv.Atoi(string(c)) |
| 111 | + if e != nil { |
| 112 | + *cursor-- |
| 113 | + return NO_VERSION, e |
| 114 | + } |
| 115 | + |
| 116 | + return v, nil |
| 117 | + |
| 118 | +} |
| 119 | + |
| 120 | +func IsDigit(c byte) bool { |
| 121 | + return c >= '0' && c <= '9' |
| 122 | +} |
| 123 | + |
| 124 | +func NewPriority(p int) *Priority { |
| 125 | + // The Priority value is calculated by first multiplying the Facility |
| 126 | + // number by 8 and then adding the numerical value of the Severity. |
| 127 | + |
| 128 | + return &Priority{ |
| 129 | + P: p, |
| 130 | + F: Facility{Value: p / 8}, |
| 131 | + S: Severity{Value: p % 8}, |
| 132 | + } |
| 133 | +} |
| 134 | + |
| 135 | +func FindNextSpace(buff []byte, from int, l int) (int, error) { |
| 136 | + var to int |
| 137 | + |
| 138 | + for to = from; to < l; to++ { |
| 139 | + if buff[to] == ' ' { |
| 140 | + to++ |
| 141 | + return to, nil |
| 142 | + } |
| 143 | + } |
| 144 | + |
| 145 | + return 0, ErrNoSpace |
| 146 | +} |
| 147 | + |
| 148 | +func Parse2Digits(buff []byte, cursor *int, l int, min int, max int, e error) (int, error) { |
| 149 | + digitLen := 2 |
| 150 | + |
| 151 | + if *cursor+digitLen > l { |
| 152 | + return 0, ErrEOL |
| 153 | + } |
| 154 | + |
| 155 | + sub := string(buff[*cursor : *cursor+digitLen]) |
| 156 | + |
| 157 | + *cursor += digitLen |
| 158 | + |
| 159 | + i, err := strconv.Atoi(sub) |
| 160 | + if err != nil { |
| 161 | + return 0, e |
| 162 | + } |
| 163 | + |
| 164 | + if i >= min && i <= max { |
| 165 | + return i, nil |
| 166 | + } |
| 167 | + |
| 168 | + return 0, e |
| 169 | +} |
| 170 | + |
| 171 | +func ParseHostname(buff []byte, cursor *int, l int) (string, error) { |
| 172 | + from := *cursor |
| 173 | + var to int |
| 174 | + |
| 175 | + for to = from; to < l; to++ { |
| 176 | + if buff[to] == ' ' { |
| 177 | + break |
| 178 | + } |
| 179 | + } |
| 180 | + |
| 181 | + hostname := buff[from:to] |
| 182 | + |
| 183 | + *cursor = to |
| 184 | + |
| 185 | + return string(hostname), nil |
| 186 | +} |
| 187 | + |
| 188 | +func ShowCursorPos(buff []byte, cursor int) { |
| 189 | + fmt.Println(string(buff)) |
| 190 | + padding := strings.Repeat("-", cursor) |
| 191 | + fmt.Println(padding + "↑\n") |
| 192 | +} |
| 193 | + |
| 194 | +func (err *ParserError) Error() string { |
| 195 | + return err.ErrorString |
| 196 | +} |
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