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Rev | Author | Line No. | Line |
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748 | daniel-mar | 1 | unit WEID; |
2 | |||
3 | (* |
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4 | * WEID<=>OID Converter for TurboPascal |
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5 | * (c) Webfan.de, ViaThinkSoft |
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1377 | daniel-mar | 6 | * Revision 2023-08-10 |
748 | daniel-mar | 7 | *) |
8 | |||
9 | (* |
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1377 | daniel-mar | 10 | * What is a WEID? |
11 | * A WEID (WEhowski IDentifier) is an alternative representation of an |
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12 | * OID (Object IDentifier) defined by Till Wehowski. |
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13 | * In OIDs, arcs are in decimal base 10. In WEIDs, the arcs are in base 36. |
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14 | * Also, each WEID has a check digit at the end (called WeLuhn Check Digit). |
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15 | * |
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16 | * The full specification can be found here: https://weid.info/spec.html |
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17 | * |
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18 | * This converter supports WEID as of Spec Change #11 |
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19 | * |
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20 | * A few short notes: |
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21 | * - There are several classes of WEIDs which have different OID bases: |
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22 | * "Class A" WEID: weid:root:2-RR-? |
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23 | * oid:2.999 |
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24 | * WEID class base OID: (OID Root) |
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25 | * "Class B" WEID: weid:pen:SX0-7PR-? |
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26 | * oid:1.3.6.1.4.1.37476.9999 |
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27 | * WEID class base OID: 1.3.6.1.4.1 |
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28 | * "Class C" WEID: weid:EXAMPLE-? |
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29 | * oid:1.3.6.1.4.1.37553.8.32488192274 |
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30 | * WEID class base OID: 1.3.6.1.4.1.37553.8 |
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31 | * "Class D" WEID: weid:example.com:TEST-? is equal to weid:9-DNS-COM-EXAMPLE-TEST-? |
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32 | * Since the check digit is based on the OID, the check digit is equal for both notations. |
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33 | * oid:1.3.6.1.4.1.37553.8.9.17704.32488192274.16438.1372205 |
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34 | * WEID class base OID: 1.3.6.1.4.1.37553.8.9.17704 |
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35 | * - The last arc in a WEID is the check digit. A question mark is the wildcard for an unknown check digit. |
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36 | * In this case, the converter will return the correct expected check digit for the input. |
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37 | * - The namespace (weid:, weid:pen:, weid:root:) is case insensitive. |
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38 | * - Padding with '0' characters is valid (e.g. weid:000EXAMPLE-3) |
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39 | * The paddings do not count into the WeLuhn check digit. |
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40 | *) |
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748 | daniel-mar | 41 | |
42 | interface |
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43 | |||
44 | (* |
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45 | Translates a weid to an oid |
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46 | "weid:EXAMPLE-3" becomes "1.3.6.1.4.1.37553.8.32488192274" |
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47 | If it failed (e.g. wrong namespace, wrong checksum, etc.) then false is returned. |
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48 | If the weid ends with '?', then it will be replaced with the checksum, |
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49 | e.g. weid:EXAMPLE-? becomes weid:EXAMPLE-3 |
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50 | *) |
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51 | function WeidToOid(var weid: string): string; |
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52 | |||
53 | (* |
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54 | Converts an OID to WEID |
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55 | "1.3.6.1.4.1.37553.8.32488192274" becomes "weid:EXAMPLE-3" |
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56 | *) |
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57 | function OidToWeid(oid: string): string; |
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58 | |||
59 | implementation |
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60 | |||
61 | uses |
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62 | VtsFuncs; |
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63 | |||
64 | function weLuhnGetCheckDigit(s: string): integer; |
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65 | var |
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66 | p: integer; |
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67 | wrkstr: string; |
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68 | c: Char; |
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69 | i: Integer; |
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70 | sum: integer; |
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71 | nbdigits: Integer; |
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72 | parity: Integer; |
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73 | n: Integer; |
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74 | digit: Integer; |
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75 | begin |
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76 | (* Padding zeros don't count to the check digit (December 2021) *) |
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77 | s := '-' + s + '-'; |
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78 | while Pos('-0', s) > 0 do |
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79 | begin |
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80 | s := StringReplace(s, '-0-', #1); |
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81 | s := StringReplace(s, '-0', '-'); |
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82 | end; |
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83 | s := StringReplace(s, #1, '-0-'); |
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84 | s := Copy(s, 2, Length(s)-2); |
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85 | |||
86 | (* remove separators of the WEID string *) |
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87 | wrkstr := StringReplace(s, '-', ''); |
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88 | |||
89 | (* Replace 'a' with '10', 'b' with '11', etc. *) |
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90 | for c := 'A' to 'Z' do |
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91 | begin |
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92 | wrkstr := StringReplace(wrkstr, c, IntToStr(Ord(c)-Ord('A')+10)); |
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93 | end; |
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94 | |||
749 | daniel-mar | 95 | (* At the end, wrkstr should only contain digits! Verify it! *) |
748 | daniel-mar | 96 | for i := 1 to Length(wrkstr) do |
97 | begin |
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98 | if not (wrkstr[i] in ['0'..'9']) then |
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99 | begin |
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100 | weLuhnGetCheckDigit := -1; |
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101 | exit; |
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102 | end; |
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103 | end; |
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104 | |||
105 | (* Now do the standard Luhn algorithm *) |
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106 | nbdigits := Length(wrkstr); |
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107 | parity := nbdigits and 1; (* mod 2 *) |
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108 | sum := 0; |
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109 | for n := nbdigits-1 downto 0 do |
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110 | begin |
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111 | digit := StrToInt(wrkstr[n+1]); |
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112 | if (n and 1) <> parity then digit := digit * 2; |
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113 | if digit > 9 then digit := digit - 9; |
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114 | sum := sum + digit; |
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115 | end; |
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116 | |||
117 | if sum mod 10 = 0 then |
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118 | weLuhnGetCheckDigit := 0 |
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119 | else |
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120 | weLuhnGetCheckDigit := 10 - (sum mod 10); |
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121 | end; |
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122 | |||
123 | function WeidToOid(var weid: string): string; |
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124 | var |
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125 | base: string; |
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126 | namespace: string; |
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127 | p: integer; |
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128 | rest: string; |
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129 | actual_checksum: string; |
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130 | expected_checksum: integer; |
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131 | complete: string; |
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132 | oidstr: string; |
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133 | arc: string; |
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1377 | daniel-mar | 134 | domainpart: string; |
135 | tmp: string; |
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748 | daniel-mar | 136 | begin |
137 | p := LastCharPos(weid,':'); |
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138 | namespace := Copy(weid, 1, p); |
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139 | rest := Copy(weid, p+1, Length(weid)-p); |
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140 | |||
141 | namespace := LowerCase(namespace); (* namespace is case insensitive *) |
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1377 | daniel-mar | 142 | |
143 | if Copy(namespace, 1, 5) = 'weid:' then |
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748 | daniel-mar | 144 | begin |
1377 | daniel-mar | 145 | tmp := Copy(namespace, 1, Length(namespace)-1); |
146 | namespace[5] := '*'; (* to force searching the second ":" *) |
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147 | p := Pos(':', tmp); |
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148 | Delete(tmp, 1, p); |
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149 | if pos('.', tmp) > 0 then |
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150 | begin |
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151 | (* Spec Change 10: Class D / Domain-WEID *) |
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152 | if pos(':', tmp) > 0 then |
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153 | begin |
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154 | WeidToOid := ''; |
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155 | exit; |
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156 | end; |
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157 | domainpart := ''; |
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158 | while tmp <> '' do |
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159 | begin |
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160 | p := Pos('.', tmp); |
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161 | if p = 0 then |
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162 | begin |
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163 | domainpart := tmp + '-' + domainpart; |
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164 | break; |
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165 | end |
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166 | else |
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167 | begin |
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168 | domainpart := Copy(tmp, 1, p-1) + '-' + domainpart; |
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169 | Delete(tmp, 1, p); |
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170 | end; |
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171 | end; |
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172 | weid := 'weid:9-DNS-' + UpperCase(Domainpart) + Rest; |
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173 | WeidToOid := WeidToOid(weid); |
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174 | exit; |
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175 | end; |
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176 | end; |
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177 | |||
178 | if Copy(namespace, 1, 7) = 'weid:x-' then |
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179 | begin |
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180 | (* Spec Change 11: Proprietary Namespaces *) |
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181 | WeidToOid := '[Proprietary WEID Namespace]'; |
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182 | Exit; |
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183 | end |
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184 | else if namespace = 'weid:' then |
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185 | begin |
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748 | daniel-mar | 186 | (* Class C *) |
187 | base := '1-3-6-1-4-1-SZ5-8'; |
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188 | end |
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189 | else if namespace = 'weid:pen:' then |
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190 | begin |
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191 | (* Class B *) |
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192 | base := '1-3-6-1-4-1'; |
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193 | end |
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194 | else if namespace = 'weid:root:' then |
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195 | begin |
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196 | (* Class A *) |
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197 | base := ''; |
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198 | end |
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199 | else |
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200 | begin |
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201 | (* Wrong namespace *) |
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202 | WeidToOid := ''; |
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203 | Exit; |
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204 | end; |
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205 | |||
206 | weid := rest; |
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207 | |||
208 | if base <> '' then |
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209 | complete := base + '-' + weid |
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210 | else |
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211 | complete := weid; |
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212 | p := LastCharPos(complete, '-'); |
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213 | actual_checksum := Copy(complete, p+1, 1); |
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214 | complete := Copy(complete, 1, p-1); |
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215 | expected_checksum := weLuhnGetCheckDigit(complete); |
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216 | if (actual_checksum <> '?') then |
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217 | begin |
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218 | if actual_checksum <> IntToStr(expected_checksum) then |
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219 | begin |
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220 | WeidToOid := ''; (* wrong checksum *) |
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221 | Exit; |
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222 | end; |
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223 | end |
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224 | else |
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225 | begin |
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226 | (* If checksum is '?', it will be replaced by the actual checksum, *) |
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227 | (* e.g. weid:EXAMPLE-? becomes weid:EXAMPLE-3 *) |
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228 | weid := StringReplace(weid, '?', IntToStr(expected_checksum)); |
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229 | end; |
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230 | |||
231 | oidstr := ''; |
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232 | while true do |
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233 | begin |
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234 | p := Pos('-', complete); |
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235 | if p = 0 then p := Length(complete)+1; |
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236 | arc := Copy(complete, 1, p-1); |
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237 | Delete(complete, 1, p); |
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238 | oidstr := oidstr + base_convert_bigint(arc, 36, 10) + '.'; |
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239 | if complete = '' then break; |
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240 | end; |
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241 | oidstr := Copy(oidstr, 1, Length(oidstr)-1); |
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242 | |||
750 | daniel-mar | 243 | weid := LowerCase(namespace) + UpperCase(weid); (* add namespace again *) |
748 | daniel-mar | 244 | |
245 | WeidToOid := oidstr; |
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246 | end; |
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247 | |||
248 | function OidToWeid(oid: string): string; |
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249 | var |
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250 | is_class_a: boolean; |
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251 | is_class_b: boolean; |
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252 | is_class_c: boolean; |
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253 | weidstr: string; |
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254 | checksum: string; |
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255 | namespace: string; |
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256 | p: Integer; |
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257 | cd: Integer; |
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258 | res: string; |
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259 | begin |
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260 | if Copy(oid,1,1) = '.' then |
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261 | Delete(oid,1,1); (* remove leading dot *) |
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262 | |||
263 | if oid <> '' then |
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264 | begin |
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265 | weidstr := ''; |
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266 | while true do |
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267 | begin |
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268 | p := Pos('.', oid); |
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269 | if p = 1 then |
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270 | begin |
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271 | Delete(oid, 1, 1); |
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272 | end |
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273 | else if p > 0 then |
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274 | begin |
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275 | weidstr := weidstr + base_convert_bigint(Copy(oid, 1, p-1),10,36) + '-'; |
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276 | Delete(oid, 1, p); |
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277 | end |
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278 | else |
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279 | begin |
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280 | weidstr := weidstr + base_convert_bigint(oid,10,36) + '-'; |
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281 | break; |
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282 | end; |
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283 | end; |
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284 | weidstr := Copy(weidstr, 1, Length(weidstr)-1); |
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285 | end |
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286 | else |
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287 | begin |
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288 | weidstr := ''; |
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289 | end; |
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290 | |||
291 | is_class_c := (Pos('1-3-6-1-4-1-SZ5-8-', weidstr) = 1) or |
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292 | (weidstr = '1-3-6-1-4-1-SZ5-8'); |
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293 | is_class_b := ((Pos('1-3-6-1-4-1-', weidstr) = 1) or |
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294 | (weidstr = '1-3-6-1-4-1')) |
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295 | and not is_class_c; |
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296 | is_class_a := not is_class_b and not is_class_c; |
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297 | |||
298 | cd := weLuhnGetCheckDigit(weidstr); |
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299 | if cd < 0 then |
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300 | begin |
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301 | OidToWeid := weidstr; |
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302 | exit; |
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303 | end; |
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304 | checksum := IntToStr(cd); |
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305 | |||
306 | if is_class_c then |
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307 | begin |
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308 | Delete(weidstr, 1, Length('1-3-6-1-4-1-SZ5-8-')); |
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309 | namespace := 'weid:'; |
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310 | end |
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311 | else if is_class_b then |
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312 | begin |
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313 | Delete(weidstr, 1, Length('1-3-6-1-4-1-')); |
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314 | namespace := 'weid:pen:'; |
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315 | end |
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316 | else if is_class_a then |
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317 | begin |
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318 | (* weidstr stays *) |
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319 | namespace := 'weid:root:'; |
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320 | end |
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321 | else |
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322 | begin |
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323 | (* should not happen *) |
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324 | OidToWeid := ''; |
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325 | Exit; |
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326 | end; |
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327 | |||
328 | res := namespace; |
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329 | if weidstr = '' then |
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330 | res := res + checksum |
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331 | else |
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332 | res := res + weidstr + '-' + checksum; |
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333 | OidToWeid := res; |
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334 | end; |
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335 | |||
336 | end. |