2 * Copyright © 2013 Ran Benita <ran234@gmail.com>
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24 #ifndef COMPOSE_COMPOSE_H
25 #define COMPOSE_COMPOSE_H
27 #include "xkbcommon/xkbcommon-compose.h"
32 * The compose table data structure is a simple trie. An example will
33 * help. Given these sequences:
35 * <A> <B> : "first" dead_a
36 * <A> <C> <D> : "second" dead_b
37 * <E> <F> : "third" dead_c
39 * the trie would look like:
41 * [root] ---> [<A>] -----------------> [<E>] -#
44 * [<B>] ---> [<C>] -# [<F>] -#
51 * - [root] is a special empty root node.
52 * - [<X>] is a node for a sequence keysym <X>.
53 * - right arrows are `next` pointers.
54 * - down arrows are `successor` pointers.
55 * - # is a nil pointer.
57 * The nodes are all kept in a contiguous array. Pointers are represented
58 * as integer offsets into this array. A nil pointer is represented as 0
59 * (which, helpfully, is the offset of the empty root node).
61 * Nodes without a successor are leaf nodes. Since a sequence cannot be a
62 * prefix of another, these are exactly the nodes which terminate the
63 * sequences (in a bijective manner).
65 * A leaf contains the result data of its sequence. The result keysym is
66 * contained in the node struct itself; the result UTF-8 string is a byte
67 * offset into an array of the form "\0first\0second\0third" (the initial
68 * \0 is so offset 0 points to an empty string).
71 /* Fits in uint16_t, also a good idea to have some limit. */
72 #define MAX_COMPOSE_NODES 65535
76 /* Offset into xkb_compose_table::nodes. */
81 /* Offset into xkb_compose_table::nodes. */
84 /* Offset into xkb_compose_table::utf8. */
91 struct xkb_compose_table {
93 enum xkb_compose_format format;
94 enum xkb_compose_compile_flags flags;
95 struct xkb_context *ctx;
100 darray(struct compose_node) nodes;