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