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 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(planp) 63 PLAN **planp; /* pointer to top of plan (modified) */ 64 { 65 PLAN *node; /* top node removed from the plan */ 66 67 if ((node = (*planp)) == NULL) 68 return (NULL); 69 (*planp) = (*planp)->next; 70 node->next = NULL; 71 return (node); 72 } 73 74 /* 75 * yankexpr -- 76 * Removes one expression from the plan. This is used mainly by 77 * paren_squish. In comments below, an expression is either a 78 * simple node or a f_expr node containing a list of simple nodes. 79 */ 80 static PLAN * 81 yankexpr(planp) 82 PLAN **planp; /* pointer to top of plan (modified) */ 83 { 84 PLAN *next; /* temp node holding subexpression results */ 85 PLAN *node; /* pointer to returned node or expression */ 86 PLAN *tail; /* pointer to tail of subplan */ 87 PLAN *subplan; /* pointer to head of ( ) expression */ 88 89 /* first pull the top node from the plan */ 90 if ((node = yanknode(planp)) == NULL) 91 return (NULL); 92 93 /* 94 * If the node is an '(' then we recursively slurp up expressions 95 * until we find its associated ')'. If it's a closing paren we 96 * just return it and unwind our recursion; all other nodes are 97 * complete expressions, so just return them. 98 */ 99 if (node->execute == f_openparen) 100 for (tail = subplan = NULL;;) { 101 if ((next = yankexpr(planp)) == NULL) 102 err(1, "(: missing closing ')'"); 103 /* 104 * If we find a closing ')' we store the collected 105 * subplan in our '(' node and convert the node to 106 * a f_expr. The ')' we found is ignored. Otherwise, 107 * we just continue to add whatever we get to our 108 * subplan. 109 */ 110 if (next->execute == f_closeparen) { 111 if (subplan == NULL) 112 errx(1, "(): empty inner expression"); 113 node->p_data[0] = subplan; 114 node->execute = f_expr; 115 break; 116 } else { 117 if (subplan == NULL) 118 tail = subplan = next; 119 else { 120 tail->next = next; 121 tail = next; 122 } 123 tail->next = NULL; 124 } 125 } 126 return (node); 127 } 128 129 /* 130 * paren_squish -- 131 * replaces "parentheisized" plans in our search plan with "expr" nodes. 132 */ 133 PLAN * 134 paren_squish(plan) 135 PLAN *plan; /* plan with ( ) nodes */ 136 { 137 PLAN *expr; /* pointer to next expression */ 138 PLAN *tail; /* pointer to tail of result plan */ 139 PLAN *result; /* pointer to head of result plan */ 140 141 result = tail = NULL; 142 143 /* 144 * the basic idea is to have yankexpr do all our work and just 145 * collect its results together. 146 */ 147 while ((expr = yankexpr(&plan)) != NULL) { 148 /* 149 * if we find an unclaimed ')' it means there is a missing 150 * '(' someplace. 151 */ 152 if (expr->execute == f_closeparen) 153 errx(1, "): no beginning '('"); 154 155 /* add the expression to our result plan */ 156 if (result == NULL) 157 tail = result = expr; 158 else { 159 tail->next = expr; 160 tail = expr; 161 } 162 tail->next = NULL; 163 } 164 return (result); 165 } 166 167 /* 168 * not_squish -- 169 * compresses "!" expressions in our search plan. 170 */ 171 PLAN * 172 not_squish(plan) 173 PLAN *plan; /* plan to process */ 174 { 175 PLAN *next; /* next node being processed */ 176 PLAN *node; /* temporary node used in f_not processing */ 177 PLAN *tail; /* pointer to tail of result plan */ 178 PLAN *result; /* pointer to head of result plan */ 179 180 tail = result = NULL; 181 182 while ((next = yanknode(&plan))) { 183 /* 184 * if we encounter a ( expression ) then look for nots in 185 * the expr subplan. 186 */ 187 if (next->execute == f_expr) 188 next->p_data[0] = not_squish(next->p_data[0]); 189 190 /* 191 * if we encounter a not, then snag the next node and place 192 * it in the not's subplan. As an optimization we compress 193 * several not's to zero or one not. 194 */ 195 if (next->execute == f_not) { 196 int notlevel = 1; 197 198 node = yanknode(&plan); 199 while (node != NULL && node->execute == f_not) { 200 ++notlevel; 201 node = yanknode(&plan); 202 } 203 if (node == NULL) 204 errx(1, "!: no following expression"); 205 if (node->execute == f_or) 206 errx(1, "!: nothing between ! and -o"); 207 /* 208 * If we encounter ! ( expr ) then look for nots in 209 * the expr subplan. 210 */ 211 if (node->execute == f_expr) 212 node->p_data[0] = not_squish(node->p_data[0]); 213 if (notlevel % 2 != 1) 214 next = node; 215 else 216 next->p_data[0] = node; 217 } 218 219 /* add the node to our result plan */ 220 if (result == NULL) 221 tail = result = next; 222 else { 223 tail->next = next; 224 tail = next; 225 } 226 tail->next = NULL; 227 } 228 return (result); 229 } 230 231 /* 232 * or_squish -- 233 * compresses -o expressions in our search plan. 234 */ 235 PLAN * 236 or_squish(plan) 237 PLAN *plan; /* plan with ors to be squished */ 238 { 239 PLAN *next; /* next node being processed */ 240 PLAN *tail; /* pointer to tail of result plan */ 241 PLAN *result; /* pointer to head of result plan */ 242 243 tail = result = next = NULL; 244 245 while ((next = yanknode(&plan)) != NULL) { 246 /* 247 * if we encounter a ( expression ) then look for or's in 248 * the expr subplan. 249 */ 250 if (next->execute == f_expr) 251 next->p_data[0] = or_squish(next->p_data[0]); 252 253 /* if we encounter a not then look for or's in the subplan */ 254 if (next->execute == f_not) 255 next->p_data[0] = or_squish(next->p_data[0]); 256 257 /* 258 * if we encounter an or, then place our collected plan in the 259 * or's first subplan and then recursively collect the 260 * remaining stuff into the second subplan and return the or. 261 */ 262 if (next->execute == f_or) { 263 if (result == NULL) 264 errx(1, "-o: no expression before -o"); 265 next->p_data[0] = result; 266 next->p_data[1] = or_squish(plan); 267 if (next->p_data[1] == NULL) 268 errx(1, "-o: no expression after -o"); 269 return (next); 270 } 271 272 /* add the node to our result plan */ 273 if (result == NULL) 274 tail = result = next; 275 else { 276 tail->next = next; 277 tail = next; 278 } 279 tail->next = NULL; 280 } 281 return (result); 282 } 283