| /* |
| * Copyright © 2013,2021 Ran Benita <ran234@gmail.com> |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the "Software"), |
| * to deal in the Software without restriction, including without limitation |
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| * and/or sell copies of the Software, and to permit persons to whom the |
| * Software is furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice (including the next |
| * paragraph) shall be included in all copies or substantial portions of the |
| * Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
| * DEALINGS IN THE SOFTWARE. |
| */ |
| |
| #ifndef COMPOSE_COMPOSE_H |
| #define COMPOSE_COMPOSE_H |
| |
| #include "xkbcommon/xkbcommon-compose.h" |
| #include "utils.h" |
| #include "context.h" |
| |
| /* |
| * The compose table data structure is a ternary search tree. |
| * |
| * Reference: https://www.drdobbs.com/database/ternary-search-trees/184410528 |
| * Visualization: https://www.cs.usfca.edu/~galles/visualization/TST.html |
| * |
| * Short example. Given these sequences: |
| * |
| * <B> <C> : "first" dead_a |
| * <B> <D> <E> : "second" dead_b |
| * <A> <F> : "third" dead_c |
| * |
| * the tree would look like: |
| * |
| * -------- [<B>]--------- |
| * | | # |
| * v V |
| * -- [<A>] -- [<C>] -------- |
| * # | # | | |
| * v # -- [<D>] -- |
| * -- [<F>] -- # | # |
| * # | # v |
| * # -- [<E>] -- |
| * # | # |
| * # |
| * |
| * where: |
| * - [<X>] is a node for a sequence keysym <X>. |
| * - right arrows are `hikid` pointers. |
| * - left arrows are `lokid` pointers. |
| * - down arrows are `eqkid` pointers. |
| * - # is a nil pointer. |
| * |
| * The nodes are all kept in a contiguous array. Pointers are represented |
| * as integer offsets into this array. A nil pointer is represented as 0 |
| * (which, helpfully, is the offset of an empty dummy node). |
| * |
| * Nodes without an eqkid are leaf nodes. Since a sequence cannot be a |
| * prefix of another, these are exactly the nodes which terminate the |
| * sequences (in a bijective manner). |
| * |
| * A leaf contains the result data of its sequence. The result keysym is |
| * contained in the node struct itself; the result UTF-8 string is a byte |
| * offset into an array of the form "\0first\0second\0third" (the initial |
| * \0 is so offset 0 points to an empty string). |
| */ |
| |
| /* Fits in uint16_t, also a good idea to have some limit. */ |
| #define MAX_COMPOSE_NODES 65535 |
| |
| struct compose_node { |
| xkb_keysym_t keysym; |
| |
| /* Offset into xkb_compose_table::nodes or 0. */ |
| uint16_t lokid; |
| /* Offset into xkb_compose_table::nodes or 0. */ |
| uint16_t hikid; |
| |
| union { |
| struct { |
| uint32_t _pad:31; |
| bool is_leaf:1; |
| }; |
| struct { |
| uint32_t _pad:31; |
| bool is_leaf:1; |
| /* Offset into xkb_compose_table::nodes or 0. */ |
| uint16_t eqkid; |
| } internal; |
| struct { |
| /* Offset into xkb_compose_table::utf8. */ |
| uint32_t utf8:31; |
| bool is_leaf:1; |
| xkb_keysym_t keysym; |
| } leaf; |
| }; |
| }; |
| |
| struct xkb_compose_table { |
| int refcnt; |
| enum xkb_compose_format format; |
| enum xkb_compose_compile_flags flags; |
| struct xkb_context *ctx; |
| |
| char *locale; |
| |
| darray_char utf8; |
| darray(struct compose_node) nodes; |
| }; |
| |
| #endif |