kc3-lang/libxkbcommon/src/compose/table.h

Branch : - branch - android master - tag -

• Show log

  Commit

• Author : Ran Benita
  Date : 2014-09-12 18:44:30
  Hash : edc98b54
  Message : compose: add xkbcommon-compose - implementation Signed-off-by: Ran Benita <ran234@gmail.com>

• src/compose/table.h

• /*
   * Copyright © 2013 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 simple trie.  An example will
   * help.  Given these sequences:
   *
   *      <A> <B>        : "first"  dead_a
   *      <A> <C> <D>    : "second" dead_b
   *      <E> <F>        : "third"  dead_c
   *
   * the trie would look like:
   *
   * [root] ---> [<A>] -----------------> [<E>] -#
   *   |           |                        |
   *   #           v                        v
   *             [<B>] ---> [<C>] -#      [<F>] -#
   *               |          |             -
   *               #          v             #
   *                        [<D>] -#
   *                          |
   *                          #
   * where:
   * - [root] is a special empty root node.
   * - [<X>] is a node for a sequence keysym <X>.
   * - right arrows are `next` pointers.
   * - down arrows are `successor` 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 the empty root node).
   *
   * Nodes without a successor 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).
   */
  
  struct compose_node {
      xkb_keysym_t keysym;
      /* Offset into xkb_compose_table::nodes. */
      unsigned int next:31;
      bool is_leaf:1;
  
      union {
          /* Offset into xkb_compose_table::nodes. */
          uint32_t successor;
          struct {
              /* Offset into xkb_compose_table::utf8. */
              uint32_t utf8;
              xkb_keysym_t keysym;
          } leaf;
      } u;
  };
  
  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