| 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 : Peter A. Buhr
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| 12 | // Last Modified On : Thu Apr 24 18:12:59 2025
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| 13 | // Update Count : 72
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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 | forall( Decorator &, T & )
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| 21 | struct tytagref {
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| 22 | inline T &;
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| 23 | };
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| 24 |
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| 25 | forall( tOuter &, tMid &, tInner & )
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| 26 | trait embedded {
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| 27 | tytagref( tMid, tInner ) ?`inner( tOuter & );
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| 28 | };
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| 29 |
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| 30 | // embedded is reflexive, with no info (void) as the type tag
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| 31 | forall( T & )
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| 32 | static inline tytagref(void, T) ?`inner ( T & this ) { tytagref( void, T ) ret = {this}; return ret; }
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| 33 |
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| 34 |
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| 35 | //
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| 36 | // P9_EMBEDDED: Use on every case of plan-9 inheritance, to make "implements embedded" be a closure of plan-9 inheritance.
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| 37 | //
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| 38 | // struct foo {
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| 39 | // int a, b, c;
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| 40 | // inline (bar);
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| 41 | // };
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| 42 | // P9_EMBEDDED( foo, bar )
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| 43 | //
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| 44 |
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| 45 | // usual version, for structs that are top-level declarations
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| 46 | #define P9_EMBEDDED( derived, immedBase ) P9_EMBEDDED_DECL_( derived, immedBase, static ) P9_EMBEDDED_BDY_( immedBase )
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| 47 |
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| 48 | // special version, for structs that are declared in functions
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| 49 | #define P9_EMBEDDED_INFUNC( derived, immedBase ) P9_EMBEDDED_DECL_( derived, immedBase, ) P9_EMBEDDED_BDY_( immedBase )
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| 50 |
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| 51 | // forward declarations of both the above; generally not needed
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| 52 | // may help you control where the P9_EMBEEDED cruft goes, in case "right after the stuct" isn't where you want it
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| 53 | #define P9_EMBEDDED_FWD( derived, immedBase ) P9_EMBEDDED_DECL_( derived, immedBase, static ) ;
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| 54 | #define P9_EMBEDDED_FWD_INFUNC( derived, immedBase ) auto P9_EMBEDDED_DECL_( derived, immedBase, ) ;
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| 55 |
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| 56 | // private helpers
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| 57 | #define P9_EMBEDDED_DECL_( derived, immedBase, STORAGE ) \
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| 58 | forall( Tbase &, TdiscardPath & | { tytagref( TdiscardPath, Tbase ) ?`inner( immedBase & ); } ) \
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| 59 | STORAGE inline tytagref( immedBase, Tbase ) ?`inner( derived & this )
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| 60 |
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| 61 | #define P9_EMBEDDED_BDY_( immedBase ) { \
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| 62 | immedBase & ib = this; \
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| 63 | Tbase & b = ib`inner; \
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| 64 | tytagref( immedBase, Tbase ) result = { b }; \
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| 65 | return result; \
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| 66 | }
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| 67 |
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| 68 | #define EMBEDDED_VIA( OUTER, MID, INNER ) (struct { tytagref( MID, INNER ) ( * ?`inner ) ( OUTER & ); }){ ?`inner }
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| 69 |
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| 70 | #define DLINK_VIA( TE, TLINK ) EMBEDDED_VIA( TE, TLINK, dlink( TE ) )
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| 71 |
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| 72 |
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| 73 | // The origin is the position encountered at the start of iteration, signifying, "need to advance to the first element,"
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| 74 | // and at the end of iteration, signifying, "no more elements." Normal comsumption of an iterator runs "advance" as
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| 75 | // the first step, and uses the return of "advance" as a guard, before dereferencing the iterator. So normal
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| 76 | // consumption of an iterator does not dereference an iterator in origin position. The value of a pointer (underlying a
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| 77 | // refence) that is exposed publicly as an iteraor, and also a pointer stored internally in a link field, is tagged, to
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| 78 | // indicate "is the origin" (internally, is the list-head sentinel node), or untagged, to indicate "is a regular node."
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| 79 | // Intent is to help a user who dereferences an iterator in origin position (which would be an API-use error on their
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| 80 | // part), by failing fast.
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| 81 |
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| 82 | #if defined( __x86_64 )
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| 83 | // Preferred case: tag in the most-significant bit. Dereference has been shown to segfault consistently.
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| 84 | // Maintenance should list more architectures as "ok" here, to let them use the preferred case, when valid.
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| 85 | #define ORIGIN_TAG_BITNO ( 8 * sizeof( size_t ) - 1 )
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| 86 | #else
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| 87 | // Fallback case: tag in the least-significant bit. Dereference will often give an alignment error, but may not,
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| 88 | // e.g. if accessing a char-typed member. 32-bit x86 uses the most- significant bit for real room on the heap.
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| 89 | #define ORIGIN_TAG_BITNO 0
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| 90 | #endif
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| 91 | #define ORIGIN_TAG_MASK (((size_t)1) << ORIGIN_TAG_BITNO)
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| 92 |
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| 93 | #define ORIGIN_TAG_SET( p ) ((p) | ORIGIN_TAG_MASK)
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| 94 | #define ORIGIN_TAG_CLEAR( p ) ((p) & ~ORIGIN_TAG_MASK)
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| 95 | #define ORIGIN_TAG_QUERY( p ) ((p) & ORIGIN_TAG_MASK)
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| 96 |
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| 97 | forall( tE & ) {
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| 98 | struct dlink{
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| 99 | tE * next;
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| 100 | tE * prev;
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| 101 | };
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| 102 |
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| 103 | static inline void ?{}( dlink( tE ) & this ) {
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| 104 | this.next = this.prev = 0p;
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| 105 | }
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| 106 |
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| 107 | forall( tLinks & = dlink( tE ) )
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| 108 | struct dlist {
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| 109 | inline dlink( tE );
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| 110 | };
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| 111 |
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| 112 | forall( tLinks & | embedded( tE, tLinks, dlink( tE ) ) ) {
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| 113 | static inline tE * $get_list_origin_addr( dlist( tE, tLinks ) & list ) {
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| 114 | dlink( tE ) & link_from_null = (*(tE *)0p)`inner;
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| 115 | ptrdiff_t link_offset = (ptrdiff_t)&link_from_null;
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| 116 | size_t origin_addr = ((size_t)&list) - link_offset;
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| 117 | size_t preResult = ORIGIN_TAG_SET( origin_addr );
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| 118 | return (tE *)preResult;
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| 119 | }
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| 120 |
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| 121 | static inline void ?{}( dlist( tE, tLinks ) & this ) {
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| 122 | tE * listOrigin = $get_list_origin_addr( this );
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| 123 | ((dlink( tE ) &)this){ listOrigin, listOrigin };
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| 124 | }
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| 125 | }
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| 126 | }
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| 127 |
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| 128 |
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| 129 | static inline forall( tE &, tLinks & | embedded( tE, tLinks, dlink( tE ) ) ) {
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| 130 | bool isListed( tE & node ) {
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| 131 | verify( &node != 0p );
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| 132 | dlink( tE ) & node_links = node`inner;
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| 133 | return (node_links.prev != 0p) || (node_links.next != 0p);
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| 134 | }
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| 135 |
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| 136 | bool isEmpty( dlist( tE, tLinks ) & list ) {
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| 137 | tE * firstPtr = list.next;
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| 138 | if ( ORIGIN_TAG_QUERY(( size_t)firstPtr) ) firstPtr = 0p;
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| 139 | return firstPtr == 0p;
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| 140 | }
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| 141 |
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| 142 | tE & first( dlist( tE, tLinks ) & list ) {
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| 143 | tE * firstPtr = list.next;
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| 144 | if ( ORIGIN_TAG_QUERY( (size_t)firstPtr ) ) firstPtr = 0p;
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| 145 | return *firstPtr;
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| 146 | }
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| 147 |
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| 148 | tE & last( dlist( tE, tLinks ) & list ) {
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| 149 | tE * lastPtr = list.prev;
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| 150 | if ( ORIGIN_TAG_QUERY( (size_t)lastPtr) ) lastPtr = 0p;
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| 151 | return *lastPtr;
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| 152 | }
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| 153 |
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| 154 | tE & insert_before( tE & before, tE & node ) {
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| 155 | verify( &before != 0p );
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| 156 | verify( &node != 0p );
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| 157 |
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| 158 | dlink( tE ) & linkToInsert = node`inner;
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| 159 |
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| 160 | verify( linkToInsert.next == 0p );
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| 161 | verify( linkToInsert.prev == 0p );
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| 162 |
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| 163 | tE & list_pos_elem = *(tE *)ORIGIN_TAG_CLEAR( (size_t)&before );
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| 164 | dlink( tE ) & list_pos_links = list_pos_elem`inner;
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| 165 | asm( "" : : : "memory" );
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| 166 | tE & before_raw = *list_pos_links.prev;
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| 167 | tE & before_elem = *(tE *) ORIGIN_TAG_CLEAR( (size_t)&before_raw );
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| 168 | linkToInsert.next = &before;
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| 169 | linkToInsert.prev = &before_raw;
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| 170 | dlink( tE ) & beforeLinks = before_elem`inner;
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| 171 | beforeLinks.next = &node;
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| 172 | list_pos_links.prev = &node;
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| 173 | asm( "" : : : "memory" );
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| 174 | return node;
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| 175 | }
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| 176 |
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| 177 | tE & insert_after( tE & after, tE & node ) {
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| 178 | verify( &after != 0p );
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| 179 | verify( &node != 0p );
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| 180 |
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| 181 | dlink( tE ) & linkToInsert = node`inner;
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| 182 |
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| 183 | verify( linkToInsert.prev == 0p );
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| 184 | verify( linkToInsert.next == 0p );
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| 185 |
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| 186 | tE & list_pos_elem = *(tE *)ORIGIN_TAG_CLEAR( (size_t)&after );
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| 187 | dlink( tE ) & list_pos_links = list_pos_elem`inner;
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| 188 | asm( "" : : : "memory" );
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| 189 | tE & after_raw = *list_pos_links.next;
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| 190 | tE & after_elem = *(tE *)ORIGIN_TAG_CLEAR( (size_t)&after_raw );
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| 191 | linkToInsert.prev = &after;
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| 192 | linkToInsert.next = &after_raw;
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| 193 | dlink( tE ) & afterLinks = after_elem`inner;
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| 194 | afterLinks.prev = &node;
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| 195 | list_pos_links.next = &node;
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| 196 | asm( "" : : : "memory" );
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| 197 | return node;
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| 198 | }
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| 199 |
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| 200 | tE & remove( tE & node ) {
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| 201 | verify( &node != 0p );
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| 202 | verify( ! ORIGIN_TAG_QUERY( (size_t)&node) );
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| 203 |
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| 204 | dlink( tE ) & list_pos_links = node`inner;
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| 205 | tE & before_raw = *list_pos_links.prev;
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| 206 | tE & before_elem = *(tE *)ORIGIN_TAG_CLEAR( (size_t)&before_raw );
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| 207 | dlink( tE ) & before_links = before_elem`inner;
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| 208 | tE & after_raw = *list_pos_links.next;
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| 209 | tE & after_elem = *(tE *)ORIGIN_TAG_CLEAR( (size_t)&after_raw );
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| 210 | dlink( tE ) & after_links = after_elem`inner;
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| 211 | before_links.next = &after_raw;
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| 212 | after_links.prev = &before_raw;
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| 213 | asm( "" : : : "memory" );
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| 214 | list_pos_links.prev = 0p;
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| 215 | list_pos_links.next = 0p;
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| 216 | asm( "" : : : "memory" );
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| 217 | return node;
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| 218 | }
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| 219 |
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| 220 | tE & iter( dlist( tE, tLinks ) & list ) {
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| 221 | tE * origin = $get_list_origin_addr( list );
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| 222 | return *origin;
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| 223 | }
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| 224 |
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| 225 | bool recede( tE && 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.prev;
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| 229 | return &ref_inner != 0p && ! ORIGIN_TAG_QUERY( (size_t)&ref_inner );
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| 230 | }
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| 231 |
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| 232 | bool advance( tE && refx ) {
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| 233 | tE && ref_inner = refx;
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| 234 | tE & oldReferent = *(tE*)ORIGIN_TAG_CLEAR( (size_t)&ref_inner );
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| 235 | &ref_inner = oldReferent`inner.next;
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| 236 | return &ref_inner != 0p && ! ORIGIN_TAG_QUERY( (size_t)&ref_inner );
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| 237 | }
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| 238 |
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| 239 | bool isFirst( tE & node ) {
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| 240 | return recede( node );
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| 241 | }
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| 242 |
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| 243 | bool isLast( tE & node ) {
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| 244 | return advance( node );
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| 245 | }
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| 246 |
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| 247 | tE & prev( tE & node ) {
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| 248 | if ( recede( node ) ) return node;
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| 249 | return *0p;
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| 250 | }
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| 251 |
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| 252 | tE & next( tE & node ) {
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| 253 | if ( advance( node ) ) return node;
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| 254 | return *0p;
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| 255 | }
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| 256 |
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| 257 | tE & insert_first( dlist( tE, tLinks ) & list, tE & node ) {
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| 258 | insert_after( iter( list ), node );
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| 259 | return node;
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| 260 | }
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| 261 |
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| 262 | tE & insert_last( dlist( tE, tLinks ) & list, tE & node ) {
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| 263 | insert_before( iter( list ), node );
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| 264 | return node;
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| 265 | }
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| 266 | tE & insert( dlist( tE, tLinks ) & list, tE & node ) { // synonym for insert_last
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| 267 | insert_last( list, node );
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| 268 | return node;
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| 269 | }
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| 270 |
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| 271 | tE & remove_first( dlist( tE, tLinks ) & list ) {
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| 272 | tE & first_node = first( list );
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| 273 | if ( &first_node ) return remove( first_node );
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| 274 | return first_node;
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| 275 | }
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| 276 |
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| 277 | tE & remove_last( dlist( tE, tLinks ) & list ) {
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| 278 | tE & last_node = last( list );
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| 279 | if ( &last_node ) return remove( last_node );
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| 280 | return last_node;
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| 281 | }
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| 282 |
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| 283 | // Transfer the "from" list to the end of this sequence; the "from" list is empty after the transfer.
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| 284 | // void transfer( dlist( tE, tLinks ) & to, dlist( tE, tLinks ) & from ) {
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| 285 | // if ( isEmpty( from ) ) return; // "from" list empty ?
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| 286 | // if ( isEmpty( to ) ) { // "to" list empty ?
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| 287 | // root = from.root;
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| 288 | // } else { // "to" list not empty
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| 289 | // T * toEnd = (T *)uBack( root );
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| 290 | // T * fromEnd = (T *)from.uBack( from.root );
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| 291 | // uBack( root ) = fromEnd;
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| 292 | // from.uNext( fromEnd ) = root;
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| 293 | // from.uBack( from.root ) = toEnd;
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| 294 | // uNext( toEnd ) = from.root;
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| 295 | // } // if
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| 296 | // from.root = nullptr; // mark "from" list empty
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| 297 | // }
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| 298 |
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| 299 | // Transfer the "from" list up to node "n" to the end of this list; the "from" list becomes the sequence after node "n".
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| 300 | // Node "n" must be in the "from" list.
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| 301 | // void split( dlist( tE, tLinks ) & to, dlist( tE, tLinks ) & from, tE & node ) {
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| 302 | // #ifdef __U_DEBUG__
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| 303 | // if ( ! n->listed() ) abort( "(uSequence &)%p.split( %p ) : Node is not on a list.", this, n );
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| 304 | // #endif // __U_DEBUG__
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| 305 | // uSequence<T> to;
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| 306 | // to.root = from.root; // start of "to" list
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| 307 | // from.root = (T *)uNext( n ); // start of "from" list
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| 308 | // if ( to.root == from.root ) { // last node in list ?
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| 309 | // from.root = nullptr; // mark "from" list empty
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| 310 | // } else {
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| 311 | // uBack( from.root ) = (T *)uBack( to.root ); // fix "from" list
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| 312 | // uNext( uBack( to.root ) ) = from.root;
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| 313 | // uNext( n ) = to.root; // fix "to" list
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| 314 | // uBack( to.root ) = n;
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| 315 | // } // if
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| 316 | // transfer( to );
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| 317 | // }
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| 318 |
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| 319 | #if ! defined(NDEBUG) && (defined(__CFA_DEBUG__) || defined(__CFA_VERIFY__))
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| 320 | bool $validate_fwd( dlist( tE, tLinks ) & this ) {
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| 321 | if ( ! & first( this ) ) return &last( this ) == 0p;
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| 322 |
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| 323 | tE & lagElem = *0p;
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| 324 | while ( tE & it = iter( this ); advance( it ) ) {
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| 325 | if ( & lagElem == 0p && &it != & first( this ) ) return false;
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| 326 | &lagElem = ⁢
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| 327 | }
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| 328 |
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| 329 | if ( &lagElem != &last( this ) ) return false;
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| 330 |
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| 331 | // TODO: verify that it is back at iter( this );
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| 332 | return true;
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| 333 | }
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| 334 |
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| 335 | bool $validate_rev( dlist( tE, tLinks ) & this ) {
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| 336 | if ( ! & last( this ) ) return &first( this ) == 0p;
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| 337 |
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| 338 | tE & lagElem = *0p;
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| 339 | while ( tE & it = iter( this ); recede( it ) ) {
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| 340 | if ( &lagElem == 0p && &it != & last( this ) ) return false;
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| 341 | &lagElem = ⁢
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| 342 | }
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| 343 |
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| 344 | if ( &lagElem != &first( this ) ) return false;
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| 345 |
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| 346 | // TODO: verify that it is back at iter( this );
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| 347 | return true;
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| 348 | }
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| 349 |
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| 350 | bool validate( dlist( tE, tLinks ) & this ) {
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| 351 | return $validate_fwd( this ) && $validate_rev( this );
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| 352 | }
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| 353 | #endif
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| 354 | }
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| 355 |
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| 356 | // TEMPORARY, until foreach statement created.
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| 357 | #define FOREACH( list, index ) for ( typeof(iter( list )) & (index) = iter( list ); advance( index ); )
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| 358 | #define FOREACH_REV( list, index ) for ( typeof(iter( list )) & (index) = iter( list ); recede( index ); )
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| 359 | #define FOREACH_COND( list, index, expr ) for ( typeof(iter( list )) & (index) = iter( list ); advance( index ) && !(expr); )
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| 360 | #define FOREACH_REV_COND( list, index, expr ) for ( typeof(iter( list )) & (index) = iter( list ); recede( index ) && !(expr); )
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