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821df508e8
needed.
213 lines
4.9 KiB
C
213 lines
4.9 KiB
C
/*-
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* Copyright (c) 2004 Tim J. Robbins.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* "Character map" ADT. Stores mappings between pairs of characters in a
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* splay tree, with a lookup table cache to simplify looking up the first
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* bunch of characters (which are presumably more common than others).
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <assert.h>
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#include <limits.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <wchar.h>
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#include "cmap.h"
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static struct cmapnode *cmap_splay(struct cmapnode *, wint_t);
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/*
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* cmap_alloc --
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* Allocate a character map.
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*/
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struct cmap *
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cmap_alloc(void)
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{
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struct cmap *cm;
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cm = malloc(sizeof(*cm));
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if (cm == NULL)
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return (NULL);
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cm->cm_root = NULL;
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cm->cm_def = CM_DEF_SELF;
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cm->cm_havecache = false;
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cm->cm_min = cm->cm_max = 0;
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return (cm);
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}
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/*
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* cmap_add --
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* Add a mapping from "from" to "to" to the map.
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*/
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bool
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cmap_add(struct cmap *cm, wint_t from, wint_t to)
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{
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struct cmapnode *cmn, *ncmn;
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cm->cm_havecache = false;
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if (cm->cm_root == NULL) {
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cmn = malloc(sizeof(*cmn));
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if (cmn == NULL)
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return (false);
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cmn->cmn_from = from;
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cmn->cmn_to = to;
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cmn->cmn_left = cmn->cmn_right = NULL;
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cm->cm_root = cmn;
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cm->cm_min = cm->cm_max = from;
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return (true);
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}
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cmn = cm->cm_root = cmap_splay(cm->cm_root, from);
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if (cmn->cmn_from == from) {
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cmn->cmn_to = to;
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return (true);
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}
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ncmn = malloc(sizeof(*ncmn));
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if (ncmn == NULL)
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return (false);
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ncmn->cmn_from = from;
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ncmn->cmn_to = to;
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if (from < cmn->cmn_from) {
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ncmn->cmn_left = cmn->cmn_left;
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ncmn->cmn_right = cmn;
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cmn->cmn_left = NULL;
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} else {
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ncmn->cmn_right = cmn->cmn_right;
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ncmn->cmn_left = cmn;
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cmn->cmn_right = NULL;
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}
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if (from < cm->cm_min)
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cm->cm_min = from;
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if (from > cm->cm_max)
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cm->cm_max = from;
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cm->cm_root = ncmn;
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return (true);
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}
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/*
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* cmap_lookup_hard --
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* Look up the mapping for a character without using the cache.
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*/
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wint_t
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cmap_lookup_hard(struct cmap *cm, wint_t ch)
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{
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if (cm->cm_root != NULL) {
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cm->cm_root = cmap_splay(cm->cm_root, ch);
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if (cm->cm_root->cmn_from == ch)
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return (cm->cm_root->cmn_to);
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}
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return (cm->cm_def == CM_DEF_SELF ? ch : cm->cm_def);
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}
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/*
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* cmap_cache --
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* Update the cache.
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*/
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void
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cmap_cache(struct cmap *cm)
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{
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wint_t ch;
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for (ch = 0; ch < CM_CACHE_SIZE; ch++)
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cm->cm_cache[ch] = cmap_lookup_hard(cm, ch);
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cm->cm_havecache = true;
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}
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/*
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* cmap_default --
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* Change the value that characters without mappings map to, and
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* return the old value. The special character value CM_MAP_SELF
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* means characters map to themselves.
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*/
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wint_t
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cmap_default(struct cmap *cm, wint_t def)
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{
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wint_t old;
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old = cm->cm_def;
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cm->cm_def = def;
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cm->cm_havecache = false;
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return (old);
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}
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static struct cmapnode *
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cmap_splay(struct cmapnode *t, wint_t ch)
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{
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struct cmapnode N, *l, *r, *y;
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/*
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* Based on public domain code from Sleator.
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*/
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assert(t != NULL);
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N.cmn_left = N.cmn_right = NULL;
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l = r = &N;
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for (;;) {
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if (ch < t->cmn_from) {
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if (t->cmn_left != NULL &&
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ch < t->cmn_left->cmn_from) {
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y = t->cmn_left;
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t->cmn_left = y->cmn_right;
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y->cmn_right = t;
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t = y;
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}
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if (t->cmn_left == NULL)
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break;
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r->cmn_left = t;
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r = t;
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t = t->cmn_left;
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} else if (ch > t->cmn_from) {
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if (t->cmn_right != NULL &&
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ch > t->cmn_right->cmn_from) {
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y = t->cmn_right;
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t->cmn_right = y->cmn_left;
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y->cmn_left = t;
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t = y;
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}
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if (t->cmn_right == NULL)
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break;
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l->cmn_right = t;
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l = t;
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t = t->cmn_right;
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} else
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break;
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}
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l->cmn_right = t->cmn_left;
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r->cmn_left = t->cmn_right;
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t->cmn_left = N.cmn_right;
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t->cmn_right = N.cmn_left;
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return (t);
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}
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