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#include <sys/types.h> 36 37#include <err.h> 38#include <fts.h> 39#include <stdio.h> 40#include <time.h> 41 42#include "find.h" 43 44static PLAN *yanknode(PLAN **); 45static PLAN *yankexpr(PLAN **); 46 47/* 48 * yanknode -- 49 * destructively removes the top from the plan 50 */ 51static PLAN * 52yanknode(PLAN **planp) 53{ 54 PLAN *node; /* top node removed from the plan */ 55 56 if ((node = (*planp)) == NULL) 57 return (NULL); 58 (*planp) = (*planp)->next; 59 node->next = NULL; 60 return (node); 61} 62 63/* 64 * yankexpr -- 65 * Removes one expression from the plan. This is used mainly by 66 * paren_squish. In comments below, an expression is either a 67 * simple node or a f_expr node containing a list of simple nodes. 68 */ 69static PLAN * 70yankexpr(PLAN **planp) 71{ 72 PLAN *next; /* temp node holding subexpression results */ 73 PLAN *node; /* pointer to returned node or expression */ 74 PLAN *tail; /* pointer to tail of subplan */ 75 PLAN *subplan; /* pointer to head of ( ) expression */ 76 77 /* first pull the top node from the plan */ 78 if ((node = yanknode(planp)) == NULL) 79 return (NULL); 80 81 /* 82 * If the node is an '(' then we recursively slurp up expressions 83 * until we find its associated ')'. If it's a closing paren we 84 * just return it and unwind our recursion; all other nodes are 85 * complete expressions, so just return them. 86 */ 87 if (node->execute == f_openparen) 88 for (tail = subplan = NULL;;) { 89 if ((next = yankexpr(planp)) == NULL) 90 errx(1, "(: missing closing ')'"); 91 /* 92 * If we find a closing ')' we store the collected 93 * subplan in our '(' node and convert the node to 94 * a f_expr. The ')' we found is ignored. Otherwise, 95 * we just continue to add whatever we get to our 96 * subplan. 97 */ 98 if (next->execute == f_closeparen) { 99 if (subplan == NULL) 100 errx(1, "(): empty inner expression"); 101 node->p_data[0] = subplan; 102 node->execute = f_expr; 103 break; 104 } else { 105 if (subplan == NULL) 106 tail = subplan = next; 107 else { 108 tail->next = next; 109 tail = next; 110 } 111 tail->next = NULL; 112 } 113 } 114 return (node); 115} 116 117/* 118 * paren_squish -- 119 * replaces "parenthesized" plans in our search plan with "expr" nodes. 120 */ 121PLAN * 122paren_squish(PLAN *plan) 123{ 124 PLAN *expr; /* pointer to next expression */ 125 PLAN *tail; /* pointer to tail of result plan */ 126 PLAN *result; /* pointer to head of result plan */ 127 128 result = tail = NULL; 129 130 /* 131 * the basic idea is to have yankexpr do all our work and just 132 * collect its results together. 133 */ 134 while ((expr = yankexpr(&plan)) != NULL) { 135 /* 136 * if we find an unclaimed ')' it means there is a missing 137 * '(' someplace. 138 */ 139 if (expr->execute == f_closeparen) 140 errx(1, "): no beginning '('"); 141 142 /* add the expression to our result plan */ 143 if (result == NULL) 144 tail = result = expr; 145 else { 146 tail->next = expr; 147 tail = expr; 148 } 149 tail->next = NULL; 150 } 151 return (result); 152} 153 154/* 155 * not_squish -- 156 * compresses "!" expressions in our search plan. 157 */ 158PLAN * 159not_squish(PLAN *plan) 160{ 161 PLAN *next; /* next node being processed */ 162 PLAN *node; /* temporary node used in f_not processing */ 163 PLAN *tail; /* pointer to tail of result plan */ 164 PLAN *result; /* pointer to head of result plan */ 165 166 tail = result = NULL; 167 168 while ((next = yanknode(&plan))) { 169 /* 170 * if we encounter a ( expression ) then look for nots in 171 * the expr subplan. 172 */ 173 if (next->execute == f_expr) 174 next->p_data[0] = not_squish(next->p_data[0]); 175 176 /* 177 * if we encounter a not, then snag the next node and place 178 * it in the not's subplan. As an optimization we compress 179 * several not's to zero or one not. 180 */ 181 if (next->execute == f_not) { 182 int notlevel = 1; 183 184 node = yanknode(&plan); 185 while (node != NULL && node->execute == f_not) { 186 ++notlevel; 187 node = yanknode(&plan); 188 } 189 if (node == NULL) 190 errx(1, "!: no following expression"); 191 if (node->execute == f_or) 192 errx(1, "!: nothing between ! and -o"); 193 /* 194 * If we encounter ! ( expr ) then look for nots in 195 * the expr subplan. 196 */ 197 if (node->execute == f_expr) 198 node->p_data[0] = not_squish(node->p_data[0]); 199 if (notlevel % 2 != 1) 200 next = node; 201 else 202 next->p_data[0] = node; 203 } 204 205 /* add the node to our result plan */ 206 if (result == NULL) 207 tail = result = next; 208 else { 209 tail->next = next; 210 tail = next; 211 } 212 tail->next = NULL; 213 } 214 return (result); 215} 216 217/* 218 * or_squish -- 219 * compresses -o expressions in our search plan. 220 */ 221PLAN * 222or_squish(PLAN *plan) 223{ 224 PLAN *next; /* next node being processed */ 225 PLAN *tail; /* pointer to tail of result plan */ 226 PLAN *result; /* pointer to head of result plan */ 227 228 tail = result = next = NULL; 229 230 while ((next = yanknode(&plan)) != NULL) { 231 /* 232 * if we encounter a ( expression ) then look for or's in 233 * the expr subplan. 234 */ 235 if (next->execute == f_expr) 236 next->p_data[0] = or_squish(next->p_data[0]); 237 238 /* if we encounter a not then look for or's in the subplan */ 239 if (next->execute == f_not) 240 next->p_data[0] = or_squish(next->p_data[0]); 241 242 /* 243 * if we encounter an or, then place our collected plan in the 244 * or's first subplan and then recursively collect the 245 * remaining stuff into the second subplan and return the or. 246 */ 247 if (next->execute == f_or) { 248 if (result == NULL) 249 errx(1, "-o: no expression before -o"); 250 next->p_data[0] = result; 251 next->p_data[1] = or_squish(plan); 252 if (next->p_data[1] == NULL) 253 errx(1, "-o: no expression after -o"); 254 return (next); 255 } 256 257 /* add the node to our result plan */ 258 if (result == NULL) 259 tail = result = next; 260 else { 261 tail->next = next; 262 tail = next; 263 } 264 tail->next = NULL; 265 } 266 return (result); 267} 268