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Rev | Author | Line No. | Line |
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7983 | leency | 1 | (* |
7597 | akron1 | 2 | BSD 2-Clause License |
3 | |||
7696 | akron1 | 4 | Copyright (c) 2018-2019, 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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35 | list.last := item; |
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36 | item.prev := NIL; |
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37 | item.next := NIL |
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38 | ELSE |
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39 | ASSERT(list.last # NIL); |
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40 | |||
41 | item.prev := list.last; |
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42 | list.last.next := item; |
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43 | item.next := NIL; |
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44 | list.last := item |
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45 | END |
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46 | END push; |
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47 | |||
48 | |||
49 | PROCEDURE pop* (list: LIST): ITEM; |
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50 | VAR |
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51 | last: ITEM; |
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52 | |||
53 | BEGIN |
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54 | ASSERT(list # NIL); |
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55 | |||
56 | last := list.last; |
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57 | |||
58 | IF last # NIL THEN |
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59 | IF last = list.first THEN |
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60 | list.first := NIL; |
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61 | list.last := NIL |
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62 | ELSE |
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63 | list.last := last.prev; |
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64 | list.last.next := NIL |
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65 | END; |
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66 | |||
67 | last.next := NIL; |
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68 | last.prev := NIL |
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69 | END |
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70 | |||
71 | RETURN last |
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72 | END pop; |
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73 | |||
74 | |||
75 | PROCEDURE insert* (list: LIST; cur, nov: ITEM); |
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76 | VAR |
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77 | next: ITEM; |
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78 | |||
79 | BEGIN |
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80 | ASSERT(list # NIL); |
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81 | ASSERT(nov # NIL); |
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82 | ASSERT(cur # NIL); |
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83 | |||
84 | next := cur.next; |
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85 | |||
86 | IF next # NIL THEN |
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87 | next.prev := nov; |
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88 | nov.next := next; |
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89 | cur.next := nov; |
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90 | nov.prev := cur |
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91 | ELSE |
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92 | push(list, nov) |
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93 | END |
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94 | |||
95 | END insert; |
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96 | |||
97 | |||
98 | PROCEDURE insertL* (list: LIST; cur, nov: ITEM); |
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99 | VAR |
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100 | prev: ITEM; |
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101 | |||
102 | BEGIN |
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103 | ASSERT(list # NIL); |
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104 | ASSERT(nov # NIL); |
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105 | ASSERT(cur # NIL); |
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106 | |||
107 | prev := cur.prev; |
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108 | |||
109 | IF prev # NIL THEN |
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110 | prev.next := nov; |
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111 | nov.prev := prev; |
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112 | cur.prev := nov; |
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113 | nov.next := cur |
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114 | ELSE |
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115 | nov.prev := NIL; |
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116 | cur.prev := nov; |
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117 | nov.next := cur; |
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118 | list.first := nov |
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119 | END |
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120 | |||
121 | END insertL; |
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122 | |||
123 | |||
124 | PROCEDURE delete* (list: LIST; item: ITEM); |
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125 | VAR |
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126 | prev, next: ITEM; |
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127 | |||
128 | BEGIN |
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129 | ASSERT(list # NIL); |
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130 | ASSERT(item # NIL); |
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131 | |||
132 | prev := item.prev; |
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133 | next := item.next; |
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134 | |||
135 | IF (next # NIL) & (prev # NIL) THEN |
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136 | prev.next := next; |
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137 | next.prev := prev |
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138 | ELSIF (next = NIL) & (prev = NIL) THEN |
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139 | list.first := NIL; |
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140 | list.last := NIL |
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141 | ELSIF (next = NIL) & (prev # NIL) THEN |
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142 | prev.next := NIL; |
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143 | list.last := prev |
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144 | ELSIF (next # NIL) & (prev = NIL) THEN |
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145 | next.prev := NIL; |
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146 | list.first := next |
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147 | END |
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148 | |||
149 | END delete; |
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150 | |||
151 | |||
152 | PROCEDURE count* (list: LIST): INTEGER; |
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153 | VAR |
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154 | item: ITEM; |
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155 | res: INTEGER; |
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156 | |||
157 | BEGIN |
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158 | ASSERT(list # NIL); |
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159 | res := 0; |
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160 | |||
161 | item := list.first; |
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162 | WHILE item # NIL DO |
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163 | INC(res); |
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164 | item := item.next |
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165 | END |
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166 | |||
167 | RETURN res |
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168 | END count; |
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169 | |||
170 | |||
7693 | akron1 | 171 | PROCEDURE getidx* (list: LIST; idx: INTEGER): ITEM; |
172 | VAR |
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173 | item: ITEM; |
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174 | |||
175 | BEGIN |
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176 | ASSERT(list # NIL); |
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177 | ASSERT(idx >= 0); |
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178 | |||
179 | item := list.first; |
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180 | WHILE (item # NIL) & (idx > 0) DO |
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181 | item := item.next; |
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182 | DEC(idx) |
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183 | END |
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184 | |||
185 | RETURN item |
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186 | END getidx; |
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187 | |||
188 | |||
7597 | akron1 | 189 | PROCEDURE create* (list: LIST): LIST; |
190 | BEGIN |
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191 | IF list = NIL THEN |
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192 | NEW(list) |
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193 | END; |
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194 | |||
7693 | akron1 | 195 | list.first := NIL; |
196 | list.last := NIL |
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7597 | akron1 | 197 | |
198 | RETURN list |
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199 | END create; |
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200 | |||
201 | |||
7983 | leency | 202 | END LISTS. |