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Rev | Author | Line No. | Line |
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7983 | leency | 1 | (* |
7597 | akron1 | 2 | BSD 2-Clause License |
3 | |||
8097 | maxcodehac | 4 | Copyright (c) 2018-2020, Anton Krotov |
7597 | akron1 | 5 | All rights reserved. |
6 | *) |
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7 | |||
8 | MODULE LISTS; |
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9 | |||
10 | IMPORT C := COLLECTIONS; |
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11 | |||
12 | |||
13 | TYPE |
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14 | |||
15 | ITEM* = POINTER TO RECORD (C.ITEM) |
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16 | |||
17 | prev*, next*: ITEM |
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18 | |||
19 | END; |
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20 | |||
21 | LIST* = POINTER TO RECORD |
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22 | |||
23 | first*, last*: ITEM |
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24 | |||
25 | END; |
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26 | |||
27 | |||
28 | PROCEDURE push* (list: LIST; item: ITEM); |
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29 | BEGIN |
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30 | ASSERT(list # NIL); |
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31 | ASSERT(item # NIL); |
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32 | |||
33 | IF list.first = NIL THEN |
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34 | list.first := item; |
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8097 | maxcodehac | 35 | item.prev := NIL |
7597 | akron1 | 36 | ELSE |
37 | ASSERT(list.last # NIL); |
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38 | item.prev := list.last; |
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8097 | maxcodehac | 39 | list.last.next := item |
40 | END; |
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41 | list.last := item; |
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42 | item.next := NIL |
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7597 | akron1 | 43 | END push; |
44 | |||
45 | |||
46 | PROCEDURE pop* (list: LIST): ITEM; |
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47 | VAR |
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48 | last: ITEM; |
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49 | |||
50 | BEGIN |
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51 | ASSERT(list # NIL); |
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52 | |||
53 | last := list.last; |
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54 | |||
55 | IF last # NIL THEN |
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56 | IF last = list.first THEN |
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57 | list.first := NIL; |
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58 | list.last := NIL |
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59 | ELSE |
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60 | list.last := last.prev; |
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61 | list.last.next := NIL |
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62 | END; |
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63 | |||
64 | last.next := NIL; |
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65 | last.prev := NIL |
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66 | END |
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67 | |||
68 | RETURN last |
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69 | END pop; |
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70 | |||
71 | |||
72 | PROCEDURE insert* (list: LIST; cur, nov: ITEM); |
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73 | VAR |
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74 | next: ITEM; |
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75 | |||
76 | BEGIN |
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77 | ASSERT(list # NIL); |
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78 | ASSERT(nov # NIL); |
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79 | ASSERT(cur # NIL); |
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80 | |||
81 | next := cur.next; |
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82 | |||
83 | IF next # NIL THEN |
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84 | next.prev := nov; |
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85 | nov.next := next; |
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86 | cur.next := nov; |
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87 | nov.prev := cur |
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88 | ELSE |
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89 | push(list, nov) |
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90 | END |
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91 | |||
92 | END insert; |
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93 | |||
94 | |||
95 | PROCEDURE insertL* (list: LIST; cur, nov: ITEM); |
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96 | VAR |
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97 | prev: ITEM; |
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98 | |||
99 | BEGIN |
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100 | ASSERT(list # NIL); |
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101 | ASSERT(nov # NIL); |
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102 | ASSERT(cur # NIL); |
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103 | |||
104 | prev := cur.prev; |
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105 | |||
106 | IF prev # NIL THEN |
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107 | prev.next := nov; |
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8097 | maxcodehac | 108 | nov.prev := prev |
7597 | akron1 | 109 | ELSE |
110 | nov.prev := NIL; |
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111 | list.first := nov |
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8097 | maxcodehac | 112 | END; |
113 | cur.prev := nov; |
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114 | nov.next := cur |
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7597 | akron1 | 115 | END insertL; |
116 | |||
117 | |||
118 | PROCEDURE delete* (list: LIST; item: ITEM); |
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119 | VAR |
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120 | prev, next: ITEM; |
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121 | |||
122 | BEGIN |
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123 | ASSERT(list # NIL); |
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124 | ASSERT(item # NIL); |
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125 | |||
126 | prev := item.prev; |
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127 | next := item.next; |
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128 | |||
129 | IF (next # NIL) & (prev # NIL) THEN |
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130 | prev.next := next; |
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131 | next.prev := prev |
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132 | ELSIF (next = NIL) & (prev = NIL) THEN |
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133 | list.first := NIL; |
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134 | list.last := NIL |
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135 | ELSIF (next = NIL) & (prev # NIL) THEN |
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136 | prev.next := NIL; |
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137 | list.last := prev |
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138 | ELSIF (next # NIL) & (prev = NIL) THEN |
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139 | next.prev := NIL; |
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140 | list.first := next |
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141 | END |
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142 | |||
143 | END delete; |
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144 | |||
145 | |||
146 | PROCEDURE count* (list: LIST): INTEGER; |
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147 | VAR |
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148 | item: ITEM; |
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149 | res: INTEGER; |
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150 | |||
151 | BEGIN |
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152 | ASSERT(list # NIL); |
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153 | res := 0; |
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154 | |||
155 | item := list.first; |
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156 | WHILE item # NIL DO |
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157 | INC(res); |
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158 | item := item.next |
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159 | END |
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160 | |||
161 | RETURN res |
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162 | END count; |
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163 | |||
164 | |||
7693 | akron1 | 165 | PROCEDURE getidx* (list: LIST; idx: INTEGER): ITEM; |
166 | VAR |
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167 | item: ITEM; |
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168 | |||
169 | BEGIN |
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170 | ASSERT(list # NIL); |
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171 | ASSERT(idx >= 0); |
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172 | |||
173 | item := list.first; |
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174 | WHILE (item # NIL) & (idx > 0) DO |
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175 | item := item.next; |
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176 | DEC(idx) |
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177 | END |
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178 | |||
179 | RETURN item |
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180 | END getidx; |
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181 | |||
182 | |||
7597 | akron1 | 183 | PROCEDURE create* (list: LIST): LIST; |
184 | BEGIN |
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185 | IF list = NIL THEN |
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186 | NEW(list) |
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187 | END; |
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188 | |||
7693 | akron1 | 189 | list.first := NIL; |
190 | list.last := NIL |
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7597 | akron1 | 191 | |
192 | RETURN list |
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193 | END create; |
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194 | |||
195 | |||
7983 | leency | 196 | END LISTS. |