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 #include <sys/cdefs.h> 43 __FBSDID("$FreeBSD$"); 44 45 #include <sys/types.h> 46 47 #include <err.h> 48 #include <fts.h> 49 #include <stdio.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(planp) 62 PLAN **planp; /* pointer to top of plan (modified) */ 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(planp) 81 PLAN **planp; /* pointer to top of plan (modified) */ 82 { 83 PLAN *next; /* temp node holding subexpression results */ 84 PLAN *node; /* pointer to returned node or expression */ 85 PLAN *tail; /* pointer to tail of subplan */ 86 PLAN *subplan; /* pointer to head of ( ) expression */ 87 88 /* first pull the top node from the plan */ 89 if ((node = yanknode(planp)) == NULL) 90 return (NULL); 91 92 /* 93 * If the node is an '(' then we recursively slurp up expressions 94 * until we find its associated ')'. If it's a closing paren we 95 * just return it and unwind our recursion; all other nodes are 96 * complete expressions, so just return them. 97 */ 98 if (node->execute == f_openparen) 99 for (tail = subplan = NULL;;) { 100 if ((next = yankexpr(planp)) == NULL) 101 errx(1, "(: missing closing ')'"); 102 /* 103 * If we find a closing ')' we store the collected 104 * subplan in our '(' node and convert the node to 105 * a f_expr. The ')' we found is ignored. Otherwise, 106 * we just continue to add whatever we get to our 107 * subplan. 108 */ 109 if (next->execute == f_closeparen) { 110 if (subplan == NULL) 111 errx(1, "(): empty inner expression"); 112 node->p_data[0] = subplan; 113 node->execute = f_expr; 114 break; 115 } else { 116 if (subplan == NULL) 117 tail = subplan = next; 118 else { 119 tail->next = next; 120 tail = next; 121 } 122 tail->next = NULL; 123 } 124 } 125 return (node); 126 } 127 128 /* 129 * paren_squish -- 130 * replaces "parenthesized" plans in our search plan with "expr" nodes. 131 */ 132 PLAN * 133 paren_squish(plan) 134 PLAN *plan; /* plan with ( ) nodes */ 135 { 136 PLAN *expr; /* pointer to next expression */ 137 PLAN *tail; /* pointer to tail of result plan */ 138 PLAN *result; /* pointer to head of result plan */ 139 140 result = tail = NULL; 141 142 /* 143 * the basic idea is to have yankexpr do all our work and just 144 * collect its results together. 145 */ 146 while ((expr = yankexpr(&plan)) != NULL) { 147 /* 148 * if we find an unclaimed ')' it means there is a missing 149 * '(' someplace. 150 */ 151 if (expr->execute == f_closeparen) 152 errx(1, "): no beginning '('"); 153 154 /* add the expression to our result plan */ 155 if (result == NULL) 156 tail = result = expr; 157 else { 158 tail->next = expr; 159 tail = expr; 160 } 161 tail->next = NULL; 162 } 163 return (result); 164 } 165 166 /* 167 * not_squish -- 168 * compresses "!" expressions in our search plan. 169 */ 170 PLAN * 171 not_squish(plan) 172 PLAN *plan; /* plan to process */ 173 { 174 PLAN *next; /* next node being processed */ 175 PLAN *node; /* temporary node used in f_not processing */ 176 PLAN *tail; /* pointer to tail of result plan */ 177 PLAN *result; /* pointer to head of result plan */ 178 179 tail = result = NULL; 180 181 while ((next = yanknode(&plan))) { 182 /* 183 * if we encounter a ( expression ) then look for nots in 184 * the expr subplan. 185 */ 186 if (next->execute == f_expr) 187 next->p_data[0] = not_squish(next->p_data[0]); 188 189 /* 190 * if we encounter a not, then snag the next node and place 191 * it in the not's subplan. As an optimization we compress 192 * several not's to zero or one not. 193 */ 194 if (next->execute == f_not) { 195 int notlevel = 1; 196 197 node = yanknode(&plan); 198 while (node != NULL && node->execute == f_not) { 199 ++notlevel; 200 node = yanknode(&plan); 201 } 202 if (node == NULL) 203 errx(1, "!: no following expression"); 204 if (node->execute == f_or) 205 errx(1, "!: nothing between ! and -o"); 206 /* 207 * If we encounter ! ( expr ) then look for nots in 208 * the expr subplan. 209 */ 210 if (node->execute == f_expr) 211 node->p_data[0] = not_squish(node->p_data[0]); 212 if (notlevel % 2 != 1) 213 next = node; 214 else 215 next->p_data[0] = node; 216 } 217 218 /* add the node to our result plan */ 219 if (result == NULL) 220 tail = result = next; 221 else { 222 tail->next = next; 223 tail = next; 224 } 225 tail->next = NULL; 226 } 227 return (result); 228 } 229 230 /* 231 * or_squish -- 232 * compresses -o expressions in our search plan. 233 */ 234 PLAN * 235 or_squish(plan) 236 PLAN *plan; /* plan with ors to be squished */ 237 { 238 PLAN *next; /* next node being processed */ 239 PLAN *tail; /* pointer to tail of result plan */ 240 PLAN *result; /* pointer to head of result plan */ 241 242 tail = result = next = NULL; 243 244 while ((next = yanknode(&plan)) != NULL) { 245 /* 246 * if we encounter a ( expression ) then look for or's in 247 * the expr subplan. 248 */ 249 if (next->execute == f_expr) 250 next->p_data[0] = or_squish(next->p_data[0]); 251 252 /* if we encounter a not then look for or's in the subplan */ 253 if (next->execute == f_not) 254 next->p_data[0] = or_squish(next->p_data[0]); 255 256 /* 257 * if we encounter an or, then place our collected plan in the 258 * or's first subplan and then recursively collect the 259 * remaining stuff into the second subplan and return the or. 260 */ 261 if (next->execute == f_or) { 262 if (result == NULL) 263 errx(1, "-o: no expression before -o"); 264 next->p_data[0] = result; 265 next->p_data[1] = or_squish(plan); 266 if (next->p_data[1] == NULL) 267 errx(1, "-o: no expression after -o"); 268 return (next); 269 } 270 271 /* add the node to our result plan */ 272 if (result == NULL) 273 tail = result = next; 274 else { 275 tail->next = next; 276 tail = next; 277 } 278 tail->next = NULL; 279 } 280 return (result); 281 } 282