Total Complexity | 52 |
Total Lines | 386 |
Duplicated Lines | 0 % |
Changes | 0 |
Complex classes like LinkedList often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use LinkedList, and based on these observations, apply Extract Interface, too.
1 | <?php namespace Mbh\Collection\Traits\Sequenceable; |
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25 | trait LinkedList |
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26 | { |
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27 | use LinkedList\ArrayAccess; |
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28 | use LinkedList\Countable; |
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29 | use LinkedList\Iterator; |
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30 | |||
31 | protected $head; |
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32 | protected $tail; |
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33 | protected $size; |
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34 | protected $current; |
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35 | protected $offset = -1; |
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36 | |||
37 | /** |
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38 | * Create an fixed array |
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39 | * |
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40 | * @param array|Traversable $array data |
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41 | */ |
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42 | public function __construct($array = null) |
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43 | { |
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44 | $this->head = $head = new LinkedTerminalNode(); |
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45 | $this->tail = $tail = new LinkedTerminalNode(); |
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46 | |||
47 | $head->setNext($tail); |
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48 | $tail->setPrev($head); |
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49 | |||
50 | $this->current = $this->head; |
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51 | |||
52 | if ($array) { |
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53 | $this->pushAll($array); |
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54 | } |
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55 | } |
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56 | |||
57 | public function __clone() |
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58 | { |
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59 | $list = $this->copyFromContext($this->head->next()); |
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60 | |||
61 | $this->head = $list->head; |
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62 | $this->tail = $list->tail; |
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63 | |||
64 | $this->current = $this->head; |
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65 | $this->offset = -1; |
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66 | |||
67 | $this->size = $list->size; |
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68 | } |
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69 | |||
70 | protected function backward() |
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71 | { |
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72 | $this->current = $this->current->prev(); |
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73 | $this->offset--; |
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74 | } |
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75 | |||
76 | public function clear() |
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77 | { |
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78 | $this->head->setNext($this->tail); |
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79 | $this->tail->setPrev($this->head); |
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80 | |||
81 | $this->current = $this->head; |
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82 | $this->size = 0; |
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83 | $this->offset = -1; |
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84 | } |
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85 | |||
86 | public function contains(...$values): bool |
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87 | { |
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88 | return $this->indexOf($values, $f) >= 0; |
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89 | } |
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90 | |||
91 | public function copy() |
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92 | { |
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93 | return $this->copyFromContext($this->head->next()); |
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94 | } |
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95 | |||
96 | protected function copyFromContext(LinkedNode $context) |
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97 | { |
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98 | $list = new static(); |
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99 | |||
100 | for ($n = $context; $n !== $this->tail; $n = $n->next()) { |
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101 | /** |
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102 | * @var LinkedDataNode $n |
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103 | */ |
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104 | $list->push($n->value()); |
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105 | } |
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106 | |||
107 | return $list; |
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108 | } |
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109 | |||
110 | protected function forward() |
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111 | { |
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112 | $this->current = $this->current->next(); |
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113 | $this->offset++; |
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114 | } |
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115 | |||
116 | public function first() |
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117 | { |
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118 | $this->emptyGuard(__METHOD__); |
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119 | return $this->seekHead()->value(); |
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120 | } |
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121 | |||
122 | public function get(int $index) |
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123 | { |
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124 | return $this[$index]; |
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125 | } |
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126 | |||
127 | protected function getSize() |
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128 | { |
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129 | return $this->size; |
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130 | } |
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131 | |||
132 | protected function getValues(): Traversable |
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133 | { |
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134 | return SplFixedArray::fromArray($this->toArray()); |
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135 | } |
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136 | |||
137 | protected function guardedSeek($index, $method) |
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138 | { |
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139 | $index = $this->intGuard($index); |
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140 | $this->indexGuard($index, $method); |
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141 | |||
142 | return $this->seekTo($index); |
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143 | } |
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144 | |||
145 | protected function indexGuard($offset, $method) |
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146 | { |
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147 | if (!$this->offsetExists($offset)) { |
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148 | throw new OutOfBoundsException( |
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149 | "{$method} was called with invalid index: {$offset}" |
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150 | ); |
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151 | } |
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152 | } |
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153 | |||
154 | /** |
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155 | * @param $value |
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156 | * @param callable $callback |
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157 | * @return int |
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158 | */ |
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159 | public function indexOf($value, callable $callback = null) |
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160 | { |
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161 | $equal = $f ?? function ($a, $b) { |
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162 | return $a === $b; |
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163 | }; |
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164 | |||
165 | $filter = $this->filter(function ($item) use ($equal, $value) { |
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166 | return $equal($item, $value); |
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167 | }); |
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168 | |||
169 | foreach ($filter as $key => $value) { |
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170 | return $key; |
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171 | } |
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172 | |||
173 | return -1; |
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174 | } |
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175 | |||
176 | public function insert(int $index, ...$values) |
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177 | { |
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178 | foreach ($values as &$value) { |
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179 | $this->insertBefore($index++, $value); |
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180 | } |
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181 | } |
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182 | |||
183 | /** |
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184 | * @param int $position |
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185 | * @param mixed $value |
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186 | * @return void |
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187 | * |
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188 | * @throws OutOfBoundsException |
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189 | */ |
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190 | public function insertAfter(int $position, $value) |
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191 | { |
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192 | $n = $this->guardedSeek($position, __METHOD__); |
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193 | $this->insertBetween($n, $n->next(), $value); |
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194 | $this->current = $this->current->prev(); |
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195 | } |
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196 | |||
197 | /** |
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198 | * @param int $position |
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199 | * @param mixed $value |
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200 | * @return void |
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201 | * |
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202 | * @throws OutOfBoundsException |
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203 | */ |
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204 | public function insertBefore(int $position, $value) |
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205 | { |
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206 | $n = $this->guardedSeek($position, __METHOD__); |
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207 | $this->insertBetween($n->prev(), $n, $value); |
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208 | $this->current = $this->current->next(); |
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209 | $this->offset++; |
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210 | } |
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211 | |||
212 | protected function insertBetween(LinkedNode $a, LinkedNode $b, $value) |
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213 | { |
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214 | $n = new LinkedDataNode($value); |
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215 | |||
216 | $a->setNext($n); |
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217 | $b->setPrev($n); |
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218 | |||
219 | $n->setPrev($a); |
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220 | $n->setNext($b); |
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221 | |||
222 | $this->current = $n; |
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223 | $this->size++; |
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224 | } |
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225 | |||
226 | /** |
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227 | * @param mixed $i |
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228 | * @return int |
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229 | * @throws Exception |
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230 | */ |
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231 | protected function intGuard($i) |
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232 | { |
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233 | if (filter_var($i, FILTER_VALIDATE_INT) === false) { |
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234 | throw new Exception; |
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235 | } |
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236 | |||
237 | return (int) $i; |
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238 | } |
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239 | |||
240 | public function last() |
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241 | { |
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242 | $this->emptyGuard(__METHOD__); |
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243 | return $this->seekTail()->value(); |
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244 | } |
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245 | |||
246 | public function pop() |
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247 | { |
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248 | $this->emptyGuard(__METHOD__); |
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249 | |||
250 | $n = $this->seekTail(); |
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251 | $this->removeNode($n); |
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252 | |||
253 | return $n->value(); |
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254 | } |
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255 | |||
256 | public function push(...$values) |
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257 | { |
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258 | $this->pushAll($values); |
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259 | } |
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260 | |||
261 | protected function pushAll($values) |
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262 | { |
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263 | foreach ($values as $key => $value) { |
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264 | $this->insertBetween($this->tail->prev(), $this->tail, $value); |
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265 | $this->offset = $this->size - 1; |
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266 | } |
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267 | } |
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268 | |||
269 | public function remove(int $index) |
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270 | { |
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271 | return $this->removeNode($this->guardedSeek($index, __METHOD__)); |
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272 | } |
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273 | |||
274 | protected function removeNode(LinkedNode $n) |
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275 | { |
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276 | $prev = $n->prev(); |
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277 | $next = $n->next(); |
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278 | |||
279 | $prev->setNext($next); |
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280 | $next->setPrev($prev); |
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281 | |||
282 | $this->size--; |
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283 | } |
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284 | |||
285 | /** |
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286 | * @link http://php.net/manual/en/seekableiterator.seek.php |
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287 | * @param int $position |
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288 | * @return mixed |
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289 | * @throws OutOfBoundsException |
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290 | * @throws Exception |
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291 | */ |
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292 | public function seek($position) |
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304 | } |
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305 | |||
306 | /** |
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307 | * @return LinkedDataNode |
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308 | */ |
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309 | protected function seekTail() |
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310 | { |
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311 | $this->offset = $this->size - 1; |
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312 | return $this->current = $this->tail->prev(); |
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313 | } |
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314 | |||
315 | /** |
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316 | * @return LinkedDataNode |
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317 | */ |
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318 | protected function seekHead() |
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319 | { |
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320 | $this->offset = 0; |
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321 | return $this->current = $this->head->next(); |
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322 | } |
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323 | |||
324 | /** |
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325 | * @param $offset |
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326 | * @return LinkedDataNode |
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327 | */ |
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328 | protected function seekTo($offset) |
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329 | { |
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330 | $n = abs($diff = $this->offset - $offset); |
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331 | $action = ($diff < 0) ? 'forward' : 'backward'; |
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332 | |||
333 | for ($i = 0; $i < $n; $i++) { |
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334 | $this->$action(); |
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335 | } |
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336 | |||
337 | return $this->current; |
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338 | } |
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339 | |||
340 | /** |
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341 | * @inheritDoc |
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342 | */ |
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343 | public function set(int $index, $value) |
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344 | { |
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345 | $this->offsetSet($index, $value); |
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346 | } |
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347 | |||
348 | protected function setValues(Traversable $traversable) |
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349 | { |
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350 | $this->clear(); |
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351 | $this->pushAll($traversable); |
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352 | } |
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353 | |||
354 | public function shift() |
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362 | } |
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363 | |||
364 | /** |
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365 | * Extract the elements after the first of a list, which must be non-empty. |
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366 | * @return DoublyLinkedList |
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367 | * @throws EmptyException |
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368 | */ |
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369 | public function tail() |
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370 | { |
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371 | $this->emptyGuard(__METHOD__); |
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372 | return $this->copyFromContext($this->head->next()->next()); |
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373 | } |
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374 | |||
375 | public function toArray(): array |
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376 | { |
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377 | $array = []; |
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378 | $context = $this->head->next(); |
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379 | |||
380 | for ($n = $context; $n !== $this->tail; $n = $n->next()) { |
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381 | /** |
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382 | * @var LinkedDataNode $n |
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383 | */ |
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384 | $array[] = $n->value(); |
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385 | } |
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386 | |||
387 | return $array; |
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388 | } |
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389 | |||
390 | public function unserialize($serialized) |
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391 | { |
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392 | } |
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393 | |||
394 | public function unshift(...$values) |
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399 | } |
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400 | } |
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401 | |||
402 | /** |
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403 | * @inheritDoc |
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404 | */ |
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405 | protected function validIndex(int $index) |
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406 | { |
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407 | return $index >= 0 && $index < $this->count(); |
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408 | } |
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409 | |||
410 | abstract public function isEmpty(): bool; |
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411 | } |
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412 |