text_cmds/tr/cset.c

   1 /*-
   2  * Copyright (c) 2004 Tim J. Robbins.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26 /*
  27  * "Set of characters" ADT implemented as a splay tree of extents, with
  28  * a lookup table cache to simplify looking up the first bunch of
  29  * characters (which are presumably more common than others).
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __FBSDID("$FreeBSD: src/usr.bin/tr/cset.c,v 1.3 2004/07/14 08:33:14 tjr Exp $");
  34
  35 #include <assert.h>
  36 #include <stdbool.h>
  37 #include <stdlib.h>
  38 #include <wchar.h>
  39 #include <wctype.h>
  40 #include "cset.h"
  41
  42 static struct csnode *  cset_delete(struct csnode *, wchar_t);
  43 static __inline int     cset_rangecmp(struct csnode *, wchar_t);
  44 static struct csnode *  cset_splay(struct csnode *, wchar_t);
  45
  46 /*
  47  * cset_alloc --
  48  *      Allocate a set of characters.
  49  */
  50 struct cset *
  51 cset_alloc(void)
  52 {
  53         struct cset *cs;
  54
  55         if ((cs = malloc(sizeof(*cs))) == NULL)
  56                 return (NULL);
  57         cs->cs_root = NULL;
  58         cs->cs_classes = NULL;
  59         cs->cs_havecache = false;
  60         cs->cs_invert = false;
  61         return (cs);
  62 }
  63
  64 /*
  65  * cset_add --
  66  *      Add a character to the set.
  67  */
  68 bool
  69 cset_add(struct cset *cs, wchar_t ch)
  70 {
  71         struct csnode *csn, *ncsn;
  72         wchar_t oval;
  73
  74         cs->cs_havecache = false;
  75
  76         /*
  77          * Inserting into empty tree; new item becomes the root.
  78          */
  79         if (cs->cs_root == NULL) {
  80                 csn = malloc(sizeof(*cs->cs_root));
  81                 if (csn == NULL)
  82                         return (false);
  83                 csn->csn_left = csn->csn_right = NULL;
  84                 csn->csn_min = csn->csn_max = ch;
  85                 cs->cs_root = csn;
  86                 return (true);
  87         }
  88
  89         /*
  90          * Splay to check whether the item already exists, and otherwise,
  91          * where we should put it.
  92          */
  93         csn = cs->cs_root = cset_splay(cs->cs_root, ch);
  94
  95         /*
  96          * Avoid adding duplicate nodes.
  97          */
  98         if (cset_rangecmp(csn, ch) == 0)
  99                 return (true);
 100
 101         /*
 102          * Allocate a new node and make it the new root.
 103          */
 104         ncsn = malloc(sizeof(*ncsn));
 105         if (ncsn == NULL)
 106                 return (false);
 107         ncsn->csn_min = ncsn->csn_max = ch;
 108         if (cset_rangecmp(csn, ch) < 0) {
 109                 ncsn->csn_left = csn->csn_left;
 110                 ncsn->csn_right = csn;
 111                 csn->csn_left = NULL;
 112         } else {
 113                 ncsn->csn_right = csn->csn_right;
 114                 ncsn->csn_left = csn;
 115                 csn->csn_right = NULL;
 116         }
 117         cs->cs_root = ncsn;
 118
 119         /*
 120          * Coalesce with left and right neighbours if possible.
 121          */
 122         if (ncsn->csn_left != NULL) {
 123                 ncsn->csn_left = cset_splay(ncsn->csn_left, ncsn->csn_min - 1);
 124                 if (ncsn->csn_left->csn_max == ncsn->csn_min - 1) {
 125                         oval = ncsn->csn_left->csn_min;
 126                         ncsn->csn_left = cset_delete(ncsn->csn_left,
 127                             ncsn->csn_left->csn_min);
 128                         ncsn->csn_min = oval;
 129                 }
 130         }
 131         if (ncsn->csn_right != NULL) {
 132                 ncsn->csn_right = cset_splay(ncsn->csn_right,
 133                     ncsn->csn_max + 1);
 134                 if (ncsn->csn_right->csn_min == ncsn->csn_max + 1) {
 135                         oval = ncsn->csn_right->csn_max;
 136                         ncsn->csn_right = cset_delete(ncsn->csn_right,
 137                             ncsn->csn_right->csn_min);
 138                         ncsn->csn_max = oval;
 139                 }
 140         }
 141
 142         return (true);
 143 }
 144
 145 /*
 146  * cset_in_hard --
 147  *      Determine whether a character is in the set without using
 148  *      the cache.
 149  */
 150 bool
 151 cset_in_hard(struct cset *cs, wchar_t ch)
 152 {
 153         struct csclass *csc;
 154
 155         for (csc = cs->cs_classes; csc != NULL; csc = csc->csc_next)
 156                 if (csc->csc_invert ^ iswctype(ch, csc->csc_type) != 0)
 157                         return (cs->cs_invert ^ true);
 158         if (cs->cs_root != NULL) {
 159                 cs->cs_root = cset_splay(cs->cs_root, ch);
 160                 return (cs->cs_invert ^ cset_rangecmp(cs->cs_root, ch) == 0);
 161         }
 162         return (cs->cs_invert ^ false);
 163 }
 164
 165 /*
 166  * cset_cache --
 167  *      Update the cache.
 168  */
 169 void
 170 cset_cache(struct cset *cs)
 171 {
 172         wchar_t i;
 173
 174         for (i = 0; i < CS_CACHE_SIZE; i++)
 175                 cs->cs_cache[i] = cset_in_hard(cs, i);
 176
 177         cs->cs_havecache = true;
 178 }
 179
 180 /*
 181  * cset_invert --
 182  *      Invert the character set.
 183  */
 184 void
 185 cset_invert(struct cset *cs)
 186 {
 187
 188         cs->cs_invert ^= true;
 189         cs->cs_havecache = false;
 190 }
 191
 192 /*
 193  * cset_addclass --
 194  *      Add a wctype()-style character class to the set, optionally
 195  *      inverting it.
 196  */
 197 bool
 198 cset_addclass(struct cset *cs, wctype_t type, bool invert)
 199 {
 200         struct csclass *csc;
 201
 202         csc = malloc(sizeof(*csc));
 203         if (csc == NULL)
 204                 return (false);
 205         csc->csc_type = type;
 206         csc->csc_invert = invert;
 207         csc->csc_next = cs->cs_classes;
 208         cs->cs_classes = csc;
 209         cs->cs_havecache = false;
 210         return (true);
 211 }
 212
 213 static __inline int
 214 cset_rangecmp(struct csnode *t, wchar_t ch)
 215 {
 216
 217         if (ch < t->csn_min)
 218                 return (-1);
 219         if (ch > t->csn_max)
 220                 return (1);
 221         return (0);
 222 }
 223
 224 static struct csnode *
 225 cset_splay(struct csnode *t, wchar_t ch)
 226 {
 227         struct csnode N, *l, *r, *y;
 228
 229         /*
 230          * Based on public domain code from Sleator.
 231          */
 232
 233         assert(t != NULL);
 234
 235         N.csn_left = N.csn_right = NULL;
 236         l = r = &N;
 237         for (;;) {
 238                 if (cset_rangecmp(t, ch) < 0) {
 239                         if (t->csn_left != NULL &&
 240                             cset_rangecmp(t->csn_left, ch) < 0) {
 241                                 y = t->csn_left;
 242                                 t->csn_left = y->csn_right;
 243                                 y->csn_right = t;
 244                                 t = y;
 245                         }
 246                         if (t->csn_left == NULL)
 247                                 break;
 248                         r->csn_left = t;
 249                         r = t;
 250                         t = t->csn_left;
 251                 } else if (cset_rangecmp(t, ch) > 0) {
 252                         if (t->csn_right != NULL &&
 253                             cset_rangecmp(t->csn_right, ch) > 0) {
 254                                 y = t->csn_right;
 255                                 t->csn_right = y->csn_left;
 256                                 y->csn_left = t;
 257                                 t = y;
 258                         }
 259                         if (t->csn_right == NULL)
 260                                 break;
 261                         l->csn_right = t;
 262                         l = t;
 263                         t = t->csn_right;
 264                 } else
 265                         break;
 266         }
 267         l->csn_right = t->csn_left;
 268         r->csn_left = t->csn_right;
 269         t->csn_left = N.csn_right;
 270         t->csn_right = N.csn_left;
 271         return (t);
 272 }
 273
 274 static struct csnode *
 275 cset_delete(struct csnode *t, wchar_t ch)
 276 {
 277         struct csnode *x;
 278
 279         assert(t != NULL);
 280         t = cset_splay(t, ch);
 281         assert(cset_rangecmp(t, ch) == 0);
 282         if (t->csn_left == NULL)
 283                 x = t->csn_right;
 284         else {
 285                 x = cset_splay(t->csn_left, ch);
 286                 x->csn_right = t->csn_right;
 287         }
 288         free(t);
 289         return x;
 290 }