git.distorted.org.uk Git - u/mdw/putty/blob - tree234.h

   1 /*
   2  * tree234.h: header defining functions in tree234.c.
   3  */
   4
   5 #ifndef TREE234_H
   6 #define TREE234_H
   7
   8 /*
   9  * These typedefs are notionally opaque outside tree234.c itself.
  10  */
  11 typedef struct node234_Tag node234;
  12 typedef struct tree234_Tag tree234;
  13 typedef struct enum234_Tag enum234;
  14
  15 /*
  16  * enum234 must be declared here because client code needs to be
  17  * able to create automatic instances of it. This declaration does
  18  * not constitute licence to use its internals outside tree234.c.
  19  * The contents of this structure may change without notice. YOU
  20  * HAVE BEEN WARNED.
  21  */
  22 struct enum234_Tag {
  23     node234 *node;
  24     int posn;
  25 };
  26
  27 typedef int (*cmpfn234)(void *, void *);
  28
  29 /*
  30  * Create a 2-3-4 tree.
  31  */
  32 tree234 *newtree234(cmpfn234 cmp);
  33
  34 /*
  35  * Free a 2-3-4 tree (not including freeing the elements).
  36  */
  37 void freetree234(tree234 *t);
  38
  39 /*
  40  * Add an element e to a 2-3-4 tree t. Returns e on success, or if
  41  * an existing element compares equal, returns that.
  42  */
  43 void *add234(tree234 *t, void *e);
  44
  45 /*
  46  * Find an element e in a 2-3-4 tree t. Returns NULL if not found.
  47  * e is always passed as the first argument to cmp, so cmp can be
  48  * an asymmetric function if desired. cmp can also be passed as
  49  * NULL, in which case the compare function from the tree proper
  50  * will be used.
  51  */
  52 void *find234(tree234 *t, void *e, cmpfn234 cmp);
  53
  54 /*
  55  * Delete an element e in a 2-3-4 tree. Does not free the element,
  56  * merely removes all links to it from the tree nodes.
  57  */
  58 void *del234(tree234 *t, void *e);
  59
  60 /*
  61  * Iterate over the elements of a tree234, in order.
  62  *
  63  *   enum234 e;
  64  *   for (p = first234(tree, &e); p; p = next234(&e)) consume(p);
  65  */
  66 void *first234(tree234 *t, enum234 *e);
  67 void *next234(enum234 *e);
  68
  69 #endif /* TREE234_H */