1 | // |
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2 | // Cforall Version 1.0.0 Copyright (C) 2020 University of Waterloo |
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3 | // |
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4 | // The contents of this file are covered under the licence agreement in the |
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5 | // file "LICENCE" distributed with Cforall. |
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6 | // |
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7 | // list -- lets a user-defined stuct form intrusive linked lists |
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8 | // |
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9 | // Author : Michael Brooks |
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10 | // Created On : Wed Apr 22 18:00:00 2020 |
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11 | // Last Modified By : Michael Brooks |
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12 | // Last Modified On : Wed Apr 22 18:00:00 2020 |
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13 | // Update Count : 1 |
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14 | // |
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15 | |
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16 | #pragma once |
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17 | |
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18 | #include <assert.h> |
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19 | |
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20 | extern "C" { |
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21 | void * memset ( void * ptr, int value, size_t num ); |
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22 | } |
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23 | |
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24 | trait embedded( tOuter &, tInner & ) { |
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25 | tInner & ?`inner( tOuter & ); |
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26 | }; |
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27 | |
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28 | // embedded is reflexive |
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29 | forall( tX & ) |
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30 | static inline tX & ?`inner( tX & this ) { return this; } |
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31 | |
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32 | // use this on every case of plan-9 inheritance, to make embedded a closure of plan-9 inheritance |
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33 | #define P9_EMBEDDED( tOuter, tInner ) \ |
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34 | static inline tInner & ?`inner( tOuter & this ) { return this; } |
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35 | |
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36 | |
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37 | // The origin is the position encountered at the start of iteration, |
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38 | // signifying, "need to advance to the first element," and at the end |
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39 | // of iteration, signifying, "no more elements." Normal comsumption of |
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40 | // an iterator runs ?`moveNext as the first step, and uses the return |
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41 | // of ?`moveNext as a guard, before dereferencing the iterator. So |
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42 | // normal consumption of an iterator does not dereference an iterator |
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43 | // in origin position. The value of a pointer (underlying a refence) |
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44 | // that is exposed publicly as an iteraor, and also a pointer stored |
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45 | // internally in a link field, is tagged, to indicate "is the origin" |
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46 | // (internally, is the list-head sentinel node), or untagged, to indicate |
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47 | // "is a regular node." Intent is to help a user who dereferences an |
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48 | // iterator in origin position (which would be an API-use error on their |
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49 | // part), by failing fast. |
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50 | |
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51 | #if defined( __x86_64 ) |
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52 | // Preferred case: tag in the most-significant bit. Dereference |
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53 | // has been shown to segfault consistently. Maintenance should |
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54 | // list more architectures as "ok" here, to let them use the |
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55 | // preferred case, when valid. |
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56 | #define ORIGIN_TAG_BITNO ( 8 * sizeof( size_t ) - 1 ) |
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57 | #else |
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58 | // Fallback case: tag in the least-significant bit. Dereference |
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59 | // will often give an alignment error, but may not, e.g. if |
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60 | // accessing a char-typed member. 32-bit x86 uses the most- |
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61 | // significant bit for real room on the heap. |
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62 | #define ORIGIN_TAG_BITNO 0 |
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63 | #endif |
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64 | #define ORIGIN_TAG_MASK (((size_t)1) << ORIGIN_TAG_BITNO) |
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65 | |
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66 | #define ORIGIN_TAG_SET(p) ((p) | ORIGIN_TAG_MASK) |
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67 | #define ORIGIN_TAG_CLEAR(p) ((p) & ~ORIGIN_TAG_MASK) |
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68 | #define ORIGIN_TAG_QUERY(p) ((p) & ORIGIN_TAG_MASK) |
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69 | |
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70 | |
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71 | forall( tE & ) { |
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72 | |
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73 | struct dlink{ |
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74 | tE *next; |
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75 | tE *prev; |
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76 | }; |
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77 | |
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78 | static inline void ?{}( dlink(tE) & this ) { |
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79 | this.next = 0p; |
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80 | this.prev = 0p; |
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81 | } |
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82 | |
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83 | forall( tLinks & = tE ) { |
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84 | |
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85 | struct dlist { |
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86 | inline dlink(tE); |
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87 | }; |
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88 | |
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89 | struct diref { |
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90 | inline tE &; |
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91 | }; |
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92 | } |
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93 | |
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94 | forall( tLinks & = tE | embedded( tE, tLinks ) | embedded( tLinks, dlink(tE) ) ) { |
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95 | static inline tE * $get_list_origin_addr( dlist(tE, tLinks) & lst ) { |
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96 | dlink(tE) & link_from_null = ( * (tE *) 0p )`inner`inner; |
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97 | ptrdiff_t link_offset = (ptrdiff_t) & link_from_null; |
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98 | size_t origin_addr = ((size_t) & lst) - link_offset; |
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99 | size_t preResult = ORIGIN_TAG_SET( origin_addr ); |
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100 | return (tE *)preResult; |
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101 | } |
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102 | |
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103 | static inline void ?{}( dlist(tE, tLinks) & this ) { |
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104 | tE * listOrigin = $get_list_origin_addr( this ); |
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105 | ( ( dlink(tE) & ) this ){ listOrigin, listOrigin } ; |
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106 | } |
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107 | |
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108 | // redundant |
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109 | // void ?{}( diref(tE, tLinks) & this, tE & target ) { |
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110 | // tE && ref = this; |
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111 | // &ref = ⌖ |
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112 | // } |
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113 | } |
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114 | |
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115 | } |
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116 | |
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117 | |
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118 | forall( tE &, tLinks & | embedded( tE, tLinks ) | embedded( tLinks, dlink(tE) ) ) { |
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119 | |
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120 | static inline void insert_after(diref(tE, tLinks) list_pos, tE &to_insert) { |
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121 | verify (&list_pos != 0p); |
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122 | verify (&to_insert != 0p); |
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123 | dlink(tE) & linkToInsert = to_insert`inner`inner; |
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124 | verify(linkToInsert.prev == 0p); |
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125 | verify(linkToInsert.next == 0p); |
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126 | tE & list_pos_raw = list_pos; |
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127 | tE & list_pos_elem = * (tE *) ORIGIN_TAG_CLEAR( (size_t) & list_pos_raw ); |
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128 | asm( "" : : : "memory" ); |
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129 | tE & after_raw = * (list_pos_elem`inner`inner).next; |
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130 | tE & after_elem = * (tE *) ORIGIN_TAG_CLEAR( (size_t) & after_raw ); |
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131 | linkToInsert.prev = & list_pos_raw; |
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132 | linkToInsert.next = & after_raw; |
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133 | (after_elem`inner`inner).prev = &to_insert; |
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134 | (list_pos_elem`inner`inner).next = &to_insert; |
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135 | asm( "" : : : "memory" ); |
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136 | } |
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137 | |
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138 | static inline void insert_before(diref(tE, tLinks) list_pos, tE &to_insert) { |
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139 | verify (&list_pos != 0p); |
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140 | verify (&to_insert != 0p); |
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141 | dlink(tE) & linkToInsert = to_insert`inner`inner; |
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142 | verify(linkToInsert.next == 0p); |
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143 | verify(linkToInsert.prev == 0p); |
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144 | tE & list_pos_raw = list_pos; |
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145 | tE & list_pos_elem = * (tE *) ORIGIN_TAG_CLEAR( (size_t) & list_pos_raw ); |
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146 | asm( "" : : : "memory" ); |
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147 | tE & before_raw = * (list_pos_elem`inner`inner).prev; |
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148 | tE & before_elem = * (tE *) ORIGIN_TAG_CLEAR( (size_t) & before_raw ); |
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149 | linkToInsert.next = & list_pos_raw; |
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150 | linkToInsert.prev = & before_raw; |
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151 | (before_elem`inner`inner).next = &to_insert; |
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152 | (list_pos_elem`inner`inner).prev = &to_insert; |
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153 | asm( "" : : : "memory" ); |
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154 | } |
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155 | |
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156 | static inline tE & remove(diref(tE, tLinks) list_pos) { |
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157 | verify (&list_pos != 0p); |
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158 | tE & list_pos_elem = list_pos; |
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159 | verify( ! ORIGIN_TAG_QUERY((size_t) & list_pos_elem) ); |
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160 | dlink(tE) & list_pos_links = list_pos_elem`inner`inner; |
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161 | tE & before_raw = * list_pos_links.prev; |
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162 | tE & before_elem = * (tE *) ORIGIN_TAG_CLEAR( (size_t) & before_raw ); |
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163 | dlink(tE) & before_links = before_elem`inner`inner; |
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164 | tE & after_raw = * list_pos_links.next; |
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165 | tE & after_elem = * (tE *) ORIGIN_TAG_CLEAR( (size_t) & after_raw ); |
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166 | dlink(tE) & after_links = after_elem`inner`inner; |
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167 | before_links.next = &after_raw; |
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168 | after_links.prev = &before_raw; |
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169 | asm( "" : : : "memory" ); |
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170 | list_pos_links.prev = 0p; |
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171 | list_pos_links.next = 0p; |
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172 | asm( "" : : : "memory" ); |
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173 | return list_pos_elem; |
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174 | } |
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175 | |
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176 | static inline diref(tE, tLinks) ?`first( dlist(tE, tLinks) &lst ) { |
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177 | tE * firstPtr = lst.next; |
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178 | if (ORIGIN_TAG_QUERY((size_t)firstPtr)) firstPtr = 0p; |
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179 | diref(tE, tLinks) ret = { *firstPtr }; |
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180 | return ret; |
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181 | } |
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182 | static inline diref(tE, tLinks) ?`last ( dlist(tE, tLinks) &lst ) { |
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183 | tE * lastPtr = lst.prev; |
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184 | if (ORIGIN_TAG_QUERY((size_t)lastPtr)) lastPtr = 0p; |
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185 | diref(tE, tLinks) ret = { *lastPtr }; |
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186 | return ret; |
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187 | } |
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188 | |
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189 | static inline bool ?`isEmpty( dlist(tE, tLinks) & lst ) { |
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190 | tE * firstPtr = lst.next; |
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191 | if (ORIGIN_TAG_QUERY((size_t)firstPtr)) firstPtr = 0p; |
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192 | return firstPtr == 0p; |
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193 | } |
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194 | |
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195 | static inline int ?!=?( const diref(tE, tLinks) & list_pos, zero_t ) { |
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196 | tE & list_pos_elem = list_pos; |
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197 | if (ORIGIN_TAG_QUERY((size_t) & list_pos_elem)) return 0; |
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198 | return & list_pos_elem != 0p; |
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199 | } |
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200 | |
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201 | static inline int DUMB_COMPARE( diref(tE, tLinks) list_pos, tE * elem ) { |
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202 | tE & signifiedLhs = list_pos; |
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203 | return &signifiedLhs == elem; |
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204 | } |
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205 | |
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206 | static inline diref(tE, tLinks) ?`from( tE & elem ) { |
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207 | diref(tE, tLinks) ret = { elem }; |
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208 | return ret; |
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209 | } |
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210 | |
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211 | static inline diref(tE, tLinks) ?`elems( dlist(tE, tLinks) & lst ) { |
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212 | tE * origin = $get_list_origin_addr( lst ); |
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213 | diref(tE, tLinks) ret = { *origin }; |
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214 | return ret; |
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215 | } |
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216 | |
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217 | static inline bool ?`moveNext( diref(tE, tLinks) & refx ) { |
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218 | tE && ref_inner = refx; |
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219 | tE & oldReferent = * (tE*) ORIGIN_TAG_CLEAR( (size_t) & ref_inner ); |
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220 | &ref_inner = oldReferent`inner`inner.next; |
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221 | return &ref_inner != 0p && |
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222 | ! ORIGIN_TAG_QUERY( (size_t) & ref_inner ); |
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223 | } |
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224 | |
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225 | static inline bool ?`movePrev( diref(tE, tLinks) & refx ) { |
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226 | tE && ref_inner = refx; |
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227 | tE & oldReferent = * (tE*) ORIGIN_TAG_CLEAR( (size_t) & ref_inner ); |
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228 | &ref_inner = oldReferent`inner`inner.prev; |
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229 | return &ref_inner != 0p && |
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230 | ! ORIGIN_TAG_QUERY( (size_t) & ref_inner ); |
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231 | } |
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232 | |
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233 | static inline bool ?`hasNext( diref(tE, tLinks) refx ) { |
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234 | return refx`moveNext; |
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235 | } |
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236 | |
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237 | static inline bool ?`hasPrev( diref(tE, tLinks) refx ) { |
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238 | return refx`movePrev; |
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239 | } |
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240 | |
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241 | static inline diref(tE, tLinks) ?`next( diref(tE, tLinks) refx ) { |
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242 | if( refx`moveNext ) return refx; |
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243 | tE && ref_inner = refx; |
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244 | & ref_inner = 0p; |
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245 | return refx; |
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246 | } |
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247 | |
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248 | static inline diref(tE, tLinks) ?`prev( diref(tE, tLinks) refx ) { |
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249 | if( refx`movePrev ) return refx; |
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250 | tE && ref_inner = refx; |
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251 | & ref_inner = 0p; |
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252 | return refx; |
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253 | } |
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254 | |
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255 | static inline void insert_first( dlist(tE, tLinks) &lst, tE & e ) { |
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256 | insert_after(lst`elems, e); |
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257 | } |
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258 | |
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259 | static inline void insert_last( dlist(tE, tLinks) &lst, tE & e ) { |
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260 | insert_before(lst`elems, e); |
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261 | } |
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262 | |
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263 | static inline tE & try_pop_front( dlist(tE, tLinks) &lst ) { |
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264 | diref(tE, tLinks) first_inlist = lst`first; |
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265 | tE & first_item = first_inlist; |
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266 | if (&first_item) remove(first_inlist); |
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267 | return first_item; |
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268 | } |
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269 | |
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270 | static inline tE & try_pop_back( dlist(tE, tLinks) &lst ) { |
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271 | diref(tE, tLinks) last_inlist = lst`last; |
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272 | tE & last_item = last_inlist; |
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273 | if (&last_item) remove(last_inlist); |
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274 | return last_item; |
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275 | } |
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276 | |
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277 | |
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278 | #if !defined(NDEBUG) && (defined(__CFA_DEBUG__) || defined(__CFA_VERIFY__)) |
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279 | static bool $validate_fwd( dlist(tE, tLinks) & this ) { |
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280 | if ( ! & this`first ) return ( (& this`last) == 0p); |
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281 | |
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282 | tE & lagElem = *0p; |
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283 | |
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284 | while ( diref(tE, tLinks) it = this`elems; it`moveNext ) { |
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285 | if (& lagElem == 0p && &it != & this`first ) return false; |
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286 | & lagElem = & it; |
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287 | } |
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288 | |
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289 | if (& lagElem != & this`last) return false; |
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290 | |
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291 | // TODO: verify that it is back at this`elems; |
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292 | return true; |
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293 | } |
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294 | static bool $validate_rev( dlist(tE, tLinks) & this ) { |
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295 | if ( ! & this`last ) return ( (& this`first) == 0p); |
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296 | |
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297 | tE & lagElem = *0p; |
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298 | |
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299 | while ( diref(tE, tLinks) it = this`elems; it`movePrev ) { |
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300 | if (& lagElem == 0p && &it != & this`last ) return false; |
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301 | & lagElem = & it; |
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302 | } |
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303 | |
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304 | if (& lagElem != & this`first) return false; |
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305 | |
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306 | // TODO: verify that it is back at this`elems; |
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307 | return true; |
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308 | } |
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309 | static bool validate( dlist(tE, tLinks) & this ) { |
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310 | return $validate_fwd(this) && $validate_rev(this); |
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311 | } |
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312 | #endif |
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313 | |
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314 | } |
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315 | |
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316 | forall( tE & | embedded( tE, dlink(tE) ) ) { |
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317 | static inline void insert_after(tE & list_pos, tE &to_insert ) { |
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318 | diref(tE, tE) list_pos_ref = list_pos`from; |
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319 | insert_after( list_pos_ref, to_insert ); |
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320 | } |
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321 | static inline void insert_before(tE & list_pos, tE &to_insert ) { |
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322 | diref(tE, tE) list_pos_ref = list_pos`from; |
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323 | insert_before( list_pos_ref, to_insert ); |
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324 | } |
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325 | static inline tE & remove(tE & list_pos ) { |
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326 | diref(tE, tE) list_pos_ref = list_pos`from; |
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327 | return remove( list_pos_ref ); |
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328 | } |
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329 | static inline bool ?`moveNext( tE && ref ) { |
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330 | diref(tE, tE) & ref_dird = (diref(tE, tE) &) & ref; |
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331 | return ref_dird`moveNext; |
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332 | } |
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333 | static inline bool ?`movePrev( tE && ref ) { |
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334 | diref(tE, tE) & ref_dird = (diref(tE, tE) &) & ref; |
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335 | return ref_dird`movePrev; |
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336 | } |
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337 | static inline bool ?`hasNext( tE & ref ) { |
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338 | diref(tE, tE) ref_dird = { ref }; |
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339 | return ref_dird`hasNext; |
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340 | } |
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341 | static inline bool ?`hasPrev( tE & ref ) { |
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342 | diref(tE, tE) ref_dird = { ref }; |
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343 | return ref_dird`hasPrev; |
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344 | } |
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345 | static inline tE & ?`next( tE & ref ) { |
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346 | diref(tE, tE) ref_dird = { ref }; |
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347 | diref(tE, tE) rslt = ref_dird`next; |
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348 | return rslt; |
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349 | } |
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350 | static inline tE & ?`prev( tE & ref ) { |
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351 | diref(tE, tE) ref_dird = { ref }; |
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352 | diref(tE, tE) rslt = ref_dird`prev; |
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353 | return rslt; |
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354 | } |
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355 | } |
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