1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Cimarron D. Taylor of the University of California, Berkeley. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)operator.c 8.1 (Berkeley) 6/6/93"; 40 #endif 41 #endif /* not lint */ 42 43 #include <sys/cdefs.h> 44 __FBSDID("$FreeBSD$"); 45 46 #include <sys/types.h> 47 48 #include <err.h> 49 #include <fts.h> 50 #include <stdio.h> 51 52 #include "find.h" 53 54 static PLAN *yanknode(PLAN **); 55 static PLAN *yankexpr(PLAN **); 56 57 /* 58 * yanknode -- 59 * destructively removes the top from the plan 60 */ 61 static PLAN * 62 yanknode(PLAN **planp) 63 { 64 PLAN *node; /* top node removed from the plan */ 65 66 if ((node = (*planp)) == NULL) 67 return (NULL); 68 (*planp) = (*planp)->next; 69 node->next = NULL; 70 return (node); 71 } 72 73 /* 74 * yankexpr -- 75 * Removes one expression from the plan. This is used mainly by 76 * paren_squish. In comments below, an expression is either a 77 * simple node or a f_expr node containing a list of simple nodes. 78 */ 79 static PLAN * 80 yankexpr(PLAN **planp) 81 { 82 PLAN *next; /* temp node holding subexpression results */ 83 PLAN *node; /* pointer to returned node or expression */ 84 PLAN *tail; /* pointer to tail of subplan */ 85 PLAN *subplan; /* pointer to head of ( ) expression */ 86 87 /* first pull the top node from the plan */ 88 if ((node = yanknode(planp)) == NULL) 89 return (NULL); 90 91 /* 92 * If the node is an '(' then we recursively slurp up expressions 93 * until we find its associated ')'. If it's a closing paren we 94 * just return it and unwind our recursion; all other nodes are 95 * complete expressions, so just return them. 96 */ 97 if (node->execute == f_openparen) 98 for (tail = subplan = NULL;;) { 99 if ((next = yankexpr(planp)) == NULL) 100 errx(1, "(: missing closing ')'"); 101 /* 102 * If we find a closing ')' we store the collected 103 * subplan in our '(' node and convert the node to 104 * a f_expr. The ')' we found is ignored. Otherwise, 105 * we just continue to add whatever we get to our 106 * subplan. 107 */ 108 if (next->execute == f_closeparen) { 109 if (subplan == NULL) 110 errx(1, "(): empty inner expression"); 111 node->p_data[0] = subplan; 112 node->execute = f_expr; 113 break; 114 } else { 115 if (subplan == NULL) 116 tail = subplan = next; 117 else { 118 tail->next = next; 119 tail = next; 120 } 121 tail->next = NULL; 122 } 123 } 124 return (node); 125 } 126 127 /* 128 * paren_squish -- 129 * replaces "parenthesized" plans in our search plan with "expr" nodes. 130 */ 131 PLAN * 132 paren_squish(PLAN *plan) 133 { 134 PLAN *expr; /* pointer to next expression */ 135 PLAN *tail; /* pointer to tail of result plan */ 136 PLAN *result; /* pointer to head of result plan */ 137 138 result = tail = NULL; 139 140 /* 141 * the basic idea is to have yankexpr do all our work and just 142 * collect its results together. 143 */ 144 while ((expr = yankexpr(&plan)) != NULL) { 145 /* 146 * if we find an unclaimed ')' it means there is a missing 147 * '(' someplace. 148 */ 149 if (expr->execute == f_closeparen) 150 errx(1, "): no beginning '('"); 151 152 /* add the expression to our result plan */ 153 if (result == NULL) 154 tail = result = expr; 155 else { 156 tail->next = expr; 157 tail = expr; 158 } 159 tail->next = NULL; 160 } 161 return (result); 162 } 163 164 /* 165 * not_squish -- 166 * compresses "!" expressions in our search plan. 167 */ 168 PLAN * 169 not_squish(PLAN *plan) 170 { 171 PLAN *next; /* next node being processed */ 172 PLAN *node; /* temporary node used in f_not processing */ 173 PLAN *tail; /* pointer to tail of result plan */ 174 PLAN *result; /* pointer to head of result plan */ 175 176 tail = result = NULL; 177 178 while ((next = yanknode(&plan))) { 179 /* 180 * if we encounter a ( expression ) then look for nots in 181 * the expr subplan. 182 */ 183 if (next->execute == f_expr) 184 next->p_data[0] = not_squish(next->p_data[0]); 185 186 /* 187 * if we encounter a not, then snag the next node and place 188 * it in the not's subplan. As an optimization we compress 189 * several not's to zero or one not. 190 */ 191 if (next->execute == f_not) { 192 int notlevel = 1; 193 194 node = yanknode(&plan); 195 while (node != NULL && node->execute == f_not) { 196 ++notlevel; 197 node = yanknode(&plan); 198 } 199 if (node == NULL) 200 errx(1, "!: no following expression"); 201 if (node->execute == f_or) 202 errx(1, "!: nothing between ! and -o"); 203 /* 204 * If we encounter ! ( expr ) then look for nots in 205 * the expr subplan. 206 */ 207 if (node->execute == f_expr) 208 node->p_data[0] = not_squish(node->p_data[0]); 209 if (notlevel % 2 != 1) 210 next = node; 211 else 212 next->p_data[0] = node; 213 } 214 215 /* add the node to our result plan */ 216 if (result == NULL) 217 tail = result = next; 218 else { 219 tail->next = next; 220 tail = next; 221 } 222 tail->next = NULL; 223 } 224 return (result); 225 } 226 227 /* 228 * or_squish -- 229 * compresses -o expressions in our search plan. 230 */ 231 PLAN * 232 or_squish(PLAN *plan) 233 { 234 PLAN *next; /* next node being processed */ 235 PLAN *tail; /* pointer to tail of result plan */ 236 PLAN *result; /* pointer to head of result plan */ 237 238 tail = result = next = NULL; 239 240 while ((next = yanknode(&plan)) != NULL) { 241 /* 242 * if we encounter a ( expression ) then look for or's in 243 * the expr subplan. 244 */ 245 if (next->execute == f_expr) 246 next->p_data[0] = or_squish(next->p_data[0]); 247 248 /* if we encounter a not then look for or's in the subplan */ 249 if (next->execute == f_not) 250 next->p_data[0] = or_squish(next->p_data[0]); 251 252 /* 253 * if we encounter an or, then place our collected plan in the 254 * or's first subplan and then recursively collect the 255 * remaining stuff into the second subplan and return the or. 256 */ 257 if (next->execute == f_or) { 258 if (result == NULL) 259 errx(1, "-o: no expression before -o"); 260 next->p_data[0] = result; 261 next->p_data[1] = or_squish(plan); 262 if (next->p_data[1] == NULL) 263 errx(1, "-o: no expression after -o"); 264 return (next); 265 } 266 267 /* add the node to our result plan */ 268 if (result == NULL) 269 tail = result = next; 270 else { 271 tail->next = next; 272 tail = next; 273 } 274 tail->next = NULL; 275 } 276 return (result); 277 } 278