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| -rw-r--r-- | lib/tlists.h | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/lib/tlists.h b/lib/tlists.h new file mode 100644 index 00000000..e1ed79ea --- /dev/null +++ b/lib/tlists.h @@ -0,0 +1,172 @@ +/* + * BIRD Library -- Typed Linked Lists + * + * (c) 2022 Maria Matejka <mq@jmq.cz> + * + * Can be freely distributed and used under the terms of the GNU GPL. + * + * + * This implementation of linked lists forces its members to be + * typed. On the other hand, it needs to be implemented as ugly macros to + * keep the needed genericity. + * + * Usage: + * 1. Include this file + * 2. Define the node structure + * 3. For every list type you need to define: + * A. #define TLIST_PREFIX and other macros + * B. Include this file once again + * + * Macros to define: + * TLIST_PREFIX: prefix to prepend to everything generated + * TLIST_TYPE: the actual node type + * TLIST_ITEM: where the tlist structure is + * TLIST_WANT_WALK: if defined, generates a helper functions for list walking macros + * TLIST_WANT_ADD_HEAD: if defined, TLIST_PREFIX_add_head() is generated to + * add an item to the beginning of the list + * TLIST_WANT_ADD_TAIL: if defined, TLIST_PREFIX_add_tail() is generated to + * add an item to the end of the list + * + * TLIST_PREFIX_rem_node() is generated always. + * + * All these macros are #undef-ed by including this file. + * + * Example: + * + * #include "lib/tlists.h" + * + * struct foo { + * ... + * TLIST_NODE(bar, struct foo) baz; + * ... + * }; + * + * #define TLIST_PREFIX bar + * #define TLIST_TYPE struct foo + * #define TLIST_ITEM baz + * + * #define TLIST_WANT_WALK + * #define TLIST_WANT_ADD_HEAD + * + * #include "lib/tlists.h" + * + * ... + * (end of example) + * + */ + +#ifdef _BIRD_LIB_TLISTS_H_ +# ifdef TLIST_PREFIX + +/* Check for mandatory arguments */ +#ifndef TLIST_TYPE +#error "TLIST_TYPE must be defined" +#endif +#ifndef TLIST_ITEM +#error "TLIST_ITEM must be defined" +#endif +#ifndef TLIST_PREFIX +#error "TLIST_PREFIX must be defined" +#endif + +#define TLIST_NAME(x) MACRO_CONCAT_AFTER(TLIST_PREFIX,_##x) +#ifndef TLIST_LIST_STRUCT +#define TLIST_LIST_STRUCT TLIST_NAME(list) +#endif + +typedef struct TLIST_LIST_STRUCT { + TLIST_TYPE *first; + TLIST_TYPE *last; +} TLIST_LIST_STRUCT; + +#ifdef TLIST_WANT_WALK +static inline struct TLIST_NAME(node) * TLIST_NAME(node_get)(TLIST_TYPE *node) +{ return &(node->TLIST_ITEM); } +#endif + +#ifdef TLIST_WANT_ADD_HEAD +static inline void TLIST_NAME(add_head)(TLIST_LIST_STRUCT *list, TLIST_TYPE *node) +{ + ASSERT_DIE(!node->TLIST_ITEM.prev && !node->TLIST_ITEM.next); + if (node->TLIST_ITEM.next = list->first) + list->first->TLIST_ITEM.prev = node; + else + list->last = node; + list->first = node; +} +#endif + +#ifdef TLIST_WANT_ADD_TAIL +static inline void TLIST_NAME(add_tail)(TLIST_LIST_STRUCT *list, TLIST_TYPE *node) +{ + ASSERT_DIE(!node->TLIST_ITEM.prev && !node->TLIST_ITEM.next); + if (node->TLIST_ITEM.prev = list->last) + list->last->TLIST_ITEM.next = node; + else + list->first = node; + list->last = node; +} +#endif + +static inline void TLIST_NAME(rem_node)(TLIST_LIST_STRUCT *list, TLIST_TYPE *node) +{ + if (node->TLIST_ITEM.prev) + node->TLIST_ITEM.prev->TLIST_ITEM.next = node->TLIST_ITEM.next; + else + { + ASSERT_DIE(list->first == node); + list->first = node->TLIST_ITEM.next; + } + + if (node->TLIST_ITEM.next) + node->TLIST_ITEM.next->TLIST_ITEM.prev = node->TLIST_ITEM.prev; + else + { + ASSERT_DIE(list->last == node); + list->last = node->TLIST_ITEM.prev; + } + + node->TLIST_ITEM.next = node->TLIST_ITEM.prev = NULL; +} + +#undef TLIST_PREFIX +#undef TLIST_NAME +#undef TLIST_LIST_STRUCT +#undef TLIST_TYPE +#undef TLIST_ITEM +#undef TLIST_WANT_ADD_HEAD +#undef TLIST_WANT_ADD_TAIL + +# endif +#else +#define _BIRD_LIB_TLISTS_H_ + +#include "lib/macro.h" + +#if defined(TLIST_NAME) || defined(TLIST_PREFIX) +#error "You should first include lib/tlists.h without requesting a TLIST" +#endif + +#define TLIST_NODE(_name, _type) struct _name##_node { _type *next; _type *prev; } +#define TLIST_LIST(_name) struct _name##_list + +/* Use ->first and ->last to access HEAD and TAIL */ +#define THEAD(_name, _list) (_list)->first +#define TTAIL(_name, _list) (_list)->last + +/* Walkaround macros: simple and resilient to node removal */ +#define WALK_TLIST(_name, _node, _list) \ + for (typeof((_list)->first) _node = (_list)->first; \ + _node; _node = _name##_node_get((_node))->next) + +#define WALK_TLIST_DELSAFE(_name, _node, _list) \ + for (typeof((_list)->first) _node = (_list)->first, \ + _helper = _node ? _name##_node_get((_list)->first)->next : NULL; \ + _node; \ + (_node = _helper) ? (_helper = _name##_node_get(_helper)->next) : 0) + +/* Empty check */ +#define EMPTY_TLIST(_name, _list) (!(_list)->first) + +#endif + |