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 #else 41 static const char rcsid[] = 42 "$FreeBSD$"; 43 #endif 44 #endif /* not lint */ 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 /* 55 * yanknode -- 56 * destructively removes the top from the plan 57 */ 58 static PLAN * 59 yanknode(planp) 60 PLAN **planp; /* pointer to top of plan (modified) */ 61 { 62 PLAN *node; /* top node removed from the plan */ 63 64 if ((node = (*planp)) == NULL) 65 return (NULL); 66 (*planp) = (*planp)->next; 67 node->next = NULL; 68 return (node); 69 } 70 71 /* 72 * yankexpr -- 73 * Removes one expression from the plan. This is used mainly by 74 * paren_squish. In comments below, an expression is either a 75 * simple node or a f_expr node containing a list of simple nodes. 76 */ 77 static PLAN * 78 yankexpr(planp) 79 PLAN **planp; /* pointer to top of plan (modified) */ 80 { 81 register 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 err(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 "parentheisized" plans in our search plan with "expr" nodes. 129 */ 130 PLAN * 131 paren_squish(plan) 132 PLAN *plan; /* plan with ( ) nodes */ 133 { 134 register PLAN *expr; /* pointer to next expression */ 135 register 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) 170 PLAN *plan; /* plan to process */ 171 { 172 register PLAN *next; /* next node being processed */ 173 register PLAN *node; /* temporary node used in f_not processing */ 174 register PLAN *tail; /* pointer to tail of result plan */ 175 PLAN *result; /* pointer to head of result plan */ 176 177 tail = result = NULL; 178 179 while (next = yanknode(&plan)) { 180 /* 181 * if we encounter a ( expression ) then look for nots in 182 * the expr subplan. 183 */ 184 if (next->execute == f_expr) 185 next->p_data[0] = not_squish(next->p_data[0]); 186 187 /* 188 * if we encounter a not, then snag the next node and place 189 * it in the not's subplan. As an optimization we compress 190 * several not's to zero or one not. 191 */ 192 if (next->execute == f_not) { 193 int notlevel = 1; 194 195 node = yanknode(&plan); 196 while (node != NULL && node->execute == f_not) { 197 ++notlevel; 198 node = yanknode(&plan); 199 } 200 if (node == NULL) 201 errx(1, "!: no following expression"); 202 if (node->execute == f_or) 203 errx(1, "!: nothing between ! and -o"); 204 /* 205 * If we encounter ! ( expr ) then look for nots in 206 * the expr subplan. 207 */ 208 if (node->execute == f_expr) 209 node->p_data[0] = not_squish(node->p_data[0]); 210 if (notlevel % 2 != 1) 211 next = node; 212 else 213 next->p_data[0] = node; 214 } 215 216 /* add the node to our result plan */ 217 if (result == NULL) 218 tail = result = next; 219 else { 220 tail->next = next; 221 tail = next; 222 } 223 tail->next = NULL; 224 } 225 return (result); 226 } 227 228 /* 229 * or_squish -- 230 * compresses -o expressions in our search plan. 231 */ 232 PLAN * 233 or_squish(plan) 234 PLAN *plan; /* plan with ors to be squished */ 235 { 236 register PLAN *next; /* next node being processed */ 237 register PLAN *tail; /* pointer to tail of result plan */ 238 PLAN *result; /* pointer to head of result plan */ 239 240 tail = result = next = NULL; 241 242 while ((next = yanknode(&plan)) != NULL) { 243 /* 244 * if we encounter a ( expression ) then look for or's in 245 * the expr subplan. 246 */ 247 if (next->execute == f_expr) 248 next->p_data[0] = or_squish(next->p_data[0]); 249 250 /* if we encounter a not then look for or's in the subplan */ 251 if (next->execute == f_not) 252 next->p_data[0] = or_squish(next->p_data[0]); 253 254 /* 255 * if we encounter an or, then place our collected plan in the 256 * or's first subplan and then recursively collect the 257 * remaining stuff into the second subplan and return the or. 258 */ 259 if (next->execute == f_or) { 260 if (result == NULL) 261 errx(1, "-o: no expression before -o"); 262 next->p_data[0] = result; 263 next->p_data[1] = or_squish(plan); 264 if (next->p_data[1] == NULL) 265 errx(1, "-o: no expression after -o"); 266 return (next); 267 } 268 269 /* add the node to our result plan */ 270 if (result == NULL) 271 tail = result = next; 272 else { 273 tail->next = next; 274 tail = next; 275 } 276 tail->next = NULL; 277 } 278 return (result); 279 } 280