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 #ifndef lint 36 #if 0 37 static char sccsid[] = "@(#)operator.c 8.1 (Berkeley) 6/6/93"; 38 #endif 39 #endif /* not lint */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/types.h> 45 46 #include <err.h> 47 #include <fts.h> 48 #include <stdio.h> 49 #include <time.h> 50 51 #include "find.h" 52 53 static PLAN *yanknode(PLAN **); 54 static PLAN *yankexpr(PLAN **); 55 56 /* 57 * yanknode -- 58 * destructively removes the top from the plan 59 */ 60 static PLAN * 61 yanknode(PLAN **planp) 62 { 63 PLAN *node; /* top node removed from the plan */ 64 65 if ((node = (*planp)) == NULL) 66 return (NULL); 67 (*planp) = (*planp)->next; 68 node->next = NULL; 69 return (node); 70 } 71 72 /* 73 * yankexpr -- 74 * Removes one expression from the plan. This is used mainly by 75 * paren_squish. In comments below, an expression is either a 76 * simple node or a f_expr node containing a list of simple nodes. 77 */ 78 static PLAN * 79 yankexpr(PLAN **planp) 80 { 81 PLAN *next; /* temp node holding subexpression results */ 82 PLAN *node; /* pointer to returned node or expression */ 83 PLAN *tail; /* pointer to tail of subplan */ 84 PLAN *subplan; /* pointer to head of ( ) expression */ 85 86 /* first pull the top node from the plan */ 87 if ((node = yanknode(planp)) == NULL) 88 return (NULL); 89 90 /* 91 * If the node is an '(' then we recursively slurp up expressions 92 * until we find its associated ')'. If it's a closing paren we 93 * just return it and unwind our recursion; all other nodes are 94 * complete expressions, so just return them. 95 */ 96 if (node->execute == f_openparen) 97 for (tail = subplan = NULL;;) { 98 if ((next = yankexpr(planp)) == NULL) 99 errx(1, "(: missing closing ')'"); 100 /* 101 * If we find a closing ')' we store the collected 102 * subplan in our '(' node and convert the node to 103 * a f_expr. The ')' we found is ignored. Otherwise, 104 * we just continue to add whatever we get to our 105 * subplan. 106 */ 107 if (next->execute == f_closeparen) { 108 if (subplan == NULL) 109 errx(1, "(): empty inner expression"); 110 node->p_data[0] = subplan; 111 node->execute = f_expr; 112 break; 113 } else { 114 if (subplan == NULL) 115 tail = subplan = next; 116 else { 117 tail->next = next; 118 tail = next; 119 } 120 tail->next = NULL; 121 } 122 } 123 return (node); 124 } 125 126 /* 127 * paren_squish -- 128 * replaces "parenthesized" plans in our search plan with "expr" nodes. 129 */ 130 PLAN * 131 paren_squish(PLAN *plan) 132 { 133 PLAN *expr; /* pointer to next expression */ 134 PLAN *tail; /* pointer to tail of result plan */ 135 PLAN *result; /* pointer to head of result plan */ 136 137 result = tail = NULL; 138 139 /* 140 * the basic idea is to have yankexpr do all our work and just 141 * collect its results together. 142 */ 143 while ((expr = yankexpr(&plan)) != NULL) { 144 /* 145 * if we find an unclaimed ')' it means there is a missing 146 * '(' someplace. 147 */ 148 if (expr->execute == f_closeparen) 149 errx(1, "): no beginning '('"); 150 151 /* add the expression to our result plan */ 152 if (result == NULL) 153 tail = result = expr; 154 else { 155 tail->next = expr; 156 tail = expr; 157 } 158 tail->next = NULL; 159 } 160 return (result); 161 } 162 163 /* 164 * not_squish -- 165 * compresses "!" expressions in our search plan. 166 */ 167 PLAN * 168 not_squish(PLAN *plan) 169 { 170 PLAN *next; /* next node being processed */ 171 PLAN *node; /* temporary node used in f_not processing */ 172 PLAN *tail; /* pointer to tail of result plan */ 173 PLAN *result; /* pointer to head of result plan */ 174 175 tail = result = NULL; 176 177 while ((next = yanknode(&plan))) { 178 /* 179 * if we encounter a ( expression ) then look for nots in 180 * the expr subplan. 181 */ 182 if (next->execute == f_expr) 183 next->p_data[0] = not_squish(next->p_data[0]); 184 185 /* 186 * if we encounter a not, then snag the next node and place 187 * it in the not's subplan. As an optimization we compress 188 * several not's to zero or one not. 189 */ 190 if (next->execute == f_not) { 191 int notlevel = 1; 192 193 node = yanknode(&plan); 194 while (node != NULL && node->execute == f_not) { 195 ++notlevel; 196 node = yanknode(&plan); 197 } 198 if (node == NULL) 199 errx(1, "!: no following expression"); 200 if (node->execute == f_or) 201 errx(1, "!: nothing between ! and -o"); 202 /* 203 * If we encounter ! ( expr ) then look for nots in 204 * the expr subplan. 205 */ 206 if (node->execute == f_expr) 207 node->p_data[0] = not_squish(node->p_data[0]); 208 if (notlevel % 2 != 1) 209 next = node; 210 else 211 next->p_data[0] = node; 212 } 213 214 /* add the node to our result plan */ 215 if (result == NULL) 216 tail = result = next; 217 else { 218 tail->next = next; 219 tail = next; 220 } 221 tail->next = NULL; 222 } 223 return (result); 224 } 225 226 /* 227 * or_squish -- 228 * compresses -o expressions in our search plan. 229 */ 230 PLAN * 231 or_squish(PLAN *plan) 232 { 233 PLAN *next; /* next node being processed */ 234 PLAN *tail; /* pointer to tail of result plan */ 235 PLAN *result; /* pointer to head of result plan */ 236 237 tail = result = next = NULL; 238 239 while ((next = yanknode(&plan)) != NULL) { 240 /* 241 * if we encounter a ( expression ) then look for or's in 242 * the expr subplan. 243 */ 244 if (next->execute == f_expr) 245 next->p_data[0] = or_squish(next->p_data[0]); 246 247 /* if we encounter a not then look for or's in the subplan */ 248 if (next->execute == f_not) 249 next->p_data[0] = or_squish(next->p_data[0]); 250 251 /* 252 * if we encounter an or, then place our collected plan in the 253 * or's first subplan and then recursively collect the 254 * remaining stuff into the second subplan and return the or. 255 */ 256 if (next->execute == f_or) { 257 if (result == NULL) 258 errx(1, "-o: no expression before -o"); 259 next->p_data[0] = result; 260 next->p_data[1] = or_squish(plan); 261 if (next->p_data[1] == NULL) 262 errx(1, "-o: no expression after -o"); 263 return (next); 264 } 265 266 /* add the node to our result plan */ 267 if (result == NULL) 268 tail = result = next; 269 else { 270 tail->next = next; 271 tail = next; 272 } 273 tail->next = NULL; 274 } 275 return (result); 276 } 277