1/*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Cimarron D. Taylor of the University of California, Berkeley. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35#if 0 36static char sccsid[] = "@(#)operator.c 8.1 (Berkeley) 6/6/93"; 37#endif 38 39#include <sys/cdefs.h> 40__FBSDID("$FreeBSD$"); 41 42#include <sys/types.h> 43 44#include <err.h> 45#include <fts.h> 46#include <stdio.h> 47#include <time.h> 48 49#include "find.h" 50 51static PLAN *yanknode(PLAN **); 52static PLAN *yankexpr(PLAN **); 53 54/* 55 * yanknode -- 56 * destructively removes the top from the plan 57 */ 58static PLAN * 59yanknode(PLAN **planp) 60{ 61 PLAN *node; /* top node removed from the plan */ 62 63 if ((node = (*planp)) == NULL) 64 return (NULL); 65 (*planp) = (*planp)->next; 66 node->next = NULL; 67 return (node); 68} 69 70/* 71 * yankexpr -- 72 * Removes one expression from the plan. This is used mainly by 73 * paren_squish. In comments below, an expression is either a 74 * simple node or a f_expr node containing a list of simple nodes. 75 */ 76static PLAN * 77yankexpr(PLAN **planp) 78{ 79 PLAN *next; /* temp node holding subexpression results */ 80 PLAN *node; /* pointer to returned node or expression */ 81 PLAN *tail; /* pointer to tail of subplan */ 82 PLAN *subplan; /* pointer to head of ( ) expression */ 83 84 /* first pull the top node from the plan */ 85 if ((node = yanknode(planp)) == NULL) 86 return (NULL); 87 88 /* 89 * If the node is an '(' then we recursively slurp up expressions 90 * until we find its associated ')'. If it's a closing paren we 91 * just return it and unwind our recursion; all other nodes are 92 * complete expressions, so just return them. 93 */ 94 if (node->execute == f_openparen) 95 for (tail = subplan = NULL;;) { 96 if ((next = yankexpr(planp)) == NULL) 97 errx(1, "(: missing closing ')'"); 98 /* 99 * If we find a closing ')' we store the collected 100 * subplan in our '(' node and convert the node to 101 * a f_expr. The ')' we found is ignored. Otherwise, 102 * we just continue to add whatever we get to our 103 * subplan. 104 */ 105 if (next->execute == f_closeparen) { 106 if (subplan == NULL) 107 errx(1, "(): empty inner expression"); 108 node->p_data[0] = subplan; 109 node->execute = f_expr; 110 break; 111 } else { 112 if (subplan == NULL) 113 tail = subplan = next; 114 else { 115 tail->next = next; 116 tail = next; 117 } 118 tail->next = NULL; 119 } 120 } 121 return (node); 122} 123 124/* 125 * paren_squish -- 126 * replaces "parenthesized" plans in our search plan with "expr" nodes. 127 */ 128PLAN * 129paren_squish(PLAN *plan) 130{ 131 PLAN *expr; /* pointer to next expression */ 132 PLAN *tail; /* pointer to tail of result plan */ 133 PLAN *result; /* pointer to head of result plan */ 134 135 result = tail = NULL; 136 137 /* 138 * the basic idea is to have yankexpr do all our work and just 139 * collect its results together. 140 */ 141 while ((expr = yankexpr(&plan)) != NULL) { 142 /* 143 * if we find an unclaimed ')' it means there is a missing 144 * '(' someplace. 145 */ 146 if (expr->execute == f_closeparen) 147 errx(1, "): no beginning '('"); 148 149 /* add the expression to our result plan */ 150 if (result == NULL) 151 tail = result = expr; 152 else { 153 tail->next = expr; 154 tail = expr; 155 } 156 tail->next = NULL; 157 } 158 return (result); 159} 160 161/* 162 * not_squish -- 163 * compresses "!" expressions in our search plan. 164 */ 165PLAN * 166not_squish(PLAN *plan) 167{ 168 PLAN *next; /* next node being processed */ 169 PLAN *node; /* temporary node used in f_not processing */ 170 PLAN *tail; /* pointer to tail of result plan */ 171 PLAN *result; /* pointer to head of result plan */ 172 173 tail = result = NULL; 174 175 while ((next = yanknode(&plan))) { 176 /* 177 * if we encounter a ( expression ) then look for nots in 178 * the expr subplan. 179 */ 180 if (next->execute == f_expr) 181 next->p_data[0] = not_squish(next->p_data[0]); 182 183 /* 184 * if we encounter a not, then snag the next node and place 185 * it in the not's subplan. As an optimization we compress 186 * several not's to zero or one not. 187 */ 188 if (next->execute == f_not) { 189 int notlevel = 1; 190 191 node = yanknode(&plan); 192 while (node != NULL && node->execute == f_not) { 193 ++notlevel; 194 node = yanknode(&plan); 195 } 196 if (node == NULL) 197 errx(1, "!: no following expression"); 198 if (node->execute == f_or) 199 errx(1, "!: nothing between ! and -o"); 200 /* 201 * If we encounter ! ( expr ) then look for nots in 202 * the expr subplan. 203 */ 204 if (node->execute == f_expr) 205 node->p_data[0] = not_squish(node->p_data[0]); 206 if (notlevel % 2 != 1) 207 next = node; 208 else 209 next->p_data[0] = node; 210 } 211 212 /* add the node to our result plan */ 213 if (result == NULL) 214 tail = result = next; 215 else { 216 tail->next = next; 217 tail = next; 218 } 219 tail->next = NULL; 220 } 221 return (result); 222} 223 224/* 225 * or_squish -- 226 * compresses -o expressions in our search plan. 227 */ 228PLAN * 229or_squish(PLAN *plan) 230{ 231 PLAN *next; /* next node being processed */ 232 PLAN *tail; /* pointer to tail of result plan */ 233 PLAN *result; /* pointer to head of result plan */ 234 235 tail = result = next = NULL; 236 237 while ((next = yanknode(&plan)) != NULL) { 238 /* 239 * if we encounter a ( expression ) then look for or's in 240 * the expr subplan. 241 */ 242 if (next->execute == f_expr) 243 next->p_data[0] = or_squish(next->p_data[0]); 244 245 /* if we encounter a not then look for or's in the subplan */ 246 if (next->execute == f_not) 247 next->p_data[0] = or_squish(next->p_data[0]); 248 249 /* 250 * if we encounter an or, then place our collected plan in the 251 * or's first subplan and then recursively collect the 252 * remaining stuff into the second subplan and return the or. 253 */ 254 if (next->execute == f_or) { 255 if (result == NULL) 256 errx(1, "-o: no expression before -o"); 257 next->p_data[0] = result; 258 next->p_data[1] = or_squish(plan); 259 if (next->p_data[1] == NULL) 260 errx(1, "-o: no expression after -o"); 261 return (next); 262 } 263 264 /* add the node to our result plan */ 265 if (result == NULL) 266 tail = result = next; 267 else { 268 tail->next = next; 269 tail = next; 270 } 271 tail->next = NULL; 272 } 273 return (result); 274} 275