1 /* $OpenBSD: operator.c,v 1.5 1999/12/04 22:42:32 millert Exp $ */ 2 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. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #ifndef lint 40 /*static char sccsid[] = "from: @(#)operator.c 8.1 (Berkeley) 6/6/93";*/ 41 static char rcsid[] = "$OpenBSD: operator.c,v 1.5 1999/12/04 22:42:32 millert Exp $"; 42 #endif /* not lint */ 43 44 #include <sys/types.h> 45 #include <sys/stat.h> 46 47 #include <err.h> 48 #include <fts.h> 49 #include <stdio.h> 50 51 #include "find.h" 52 53 /* 54 * yanknode -- 55 * destructively removes the top from the plan 56 */ 57 static PLAN * 58 yanknode(planp) 59 PLAN **planp; /* pointer to top of plan (modified) */ 60 { 61 PLAN *node; /* top node removed from the plan */ 62 63 if ((node = (*planp)) == NULL) 64 return (NULL); 65 (*planp) = (*planp)->next; 66 node->next = NULL; 67 return (node); 68 } 69 70 /* 71 * yankexpr -- 72 * Removes one expression from the plan. This is used mainly by 73 * paren_squish. In comments below, an expression is either a 74 * simple node or a N_EXPR node containing a list of simple nodes. 75 */ 76 static PLAN * 77 yankexpr(planp) 78 PLAN **planp; /* pointer to top of plan (modified) */ 79 { 80 register PLAN *next; /* temp node holding subexpression results */ 81 PLAN *node; /* pointer to returned node or expression */ 82 PLAN *tail; /* pointer to tail of subplan */ 83 PLAN *subplan; /* pointer to head of ( ) expression */ 84 int f_expr(); 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->type == N_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 N_EXPR. The ')' we found is ignored. Otherwise, 104 * we just continue to add whatever we get to our 105 * subplan. 106 */ 107 if (next->type == N_CLOSEPAREN) { 108 if (subplan == NULL) 109 errx(1, "(): empty inner expression"); 110 node->p_data[0] = subplan; 111 node->type = N_EXPR; 112 node->eval = 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 "parentheisized" plans in our search plan with "expr" nodes. 130 */ 131 PLAN * 132 paren_squish(plan) 133 PLAN *plan; /* plan with ( ) nodes */ 134 { 135 register PLAN *expr; /* pointer to next expression */ 136 register PLAN *tail; /* pointer to tail of result plan */ 137 PLAN *result; /* pointer to head of result plan */ 138 139 result = tail = NULL; 140 141 /* 142 * the basic idea is to have yankexpr do all our work and just 143 * collect it's results together. 144 */ 145 while ((expr = yankexpr(&plan)) != NULL) { 146 /* 147 * if we find an unclaimed ')' it means there is a missing 148 * '(' someplace. 149 */ 150 if (expr->type == N_CLOSEPAREN) 151 errx(1, "): no beginning '('"); 152 153 /* add the expression to our result plan */ 154 if (result == NULL) 155 tail = result = expr; 156 else { 157 tail->next = expr; 158 tail = expr; 159 } 160 tail->next = NULL; 161 } 162 return (result); 163 } 164 165 /* 166 * not_squish -- 167 * compresses "!" expressions in our search plan. 168 */ 169 PLAN * 170 not_squish(plan) 171 PLAN *plan; /* plan to process */ 172 { 173 register PLAN *next; /* next node being processed */ 174 register PLAN *node; /* temporary node used in N_NOT processing */ 175 register PLAN *tail; /* pointer to tail of result plan */ 176 PLAN *result; /* pointer to head of result plan */ 177 178 tail = result = next = NULL; 179 180 while ((next = yanknode(&plan)) != NULL) { 181 /* 182 * if we encounter a ( expression ) then look for nots in 183 * the expr subplan. 184 */ 185 if (next->type == N_EXPR) 186 next->p_data[0] = not_squish(next->p_data[0]); 187 188 /* 189 * if we encounter a not, then snag the next node and place 190 * it in the not's subplan. As an optimization we compress 191 * several not's to zero or one not. 192 */ 193 if (next->type == N_NOT) { 194 int notlevel = 1; 195 196 node = yanknode(&plan); 197 while (node != NULL && node->type == N_NOT) { 198 ++notlevel; 199 node = yanknode(&plan); 200 } 201 if (node == NULL) 202 errx(1, "!: no following expression"); 203 if (node->type == N_OR) 204 errx(1, "!: nothing between ! and -o"); 205 if (node->type == N_EXPR) 206 node = not_squish(node); 207 if (notlevel % 2 != 1) 208 next = node; 209 else 210 next->p_data[0] = node; 211 } 212 213 /* add the node to our result plan */ 214 if (result == NULL) 215 tail = result = next; 216 else { 217 tail->next = next; 218 tail = next; 219 } 220 tail->next = NULL; 221 } 222 return (result); 223 } 224 225 /* 226 * or_squish -- 227 * compresses -o expressions in our search plan. 228 */ 229 PLAN * 230 or_squish(plan) 231 PLAN *plan; /* plan with ors to be squished */ 232 { 233 register PLAN *next; /* next node being processed */ 234 register PLAN *tail; /* pointer to tail of result plan */ 235 PLAN *result; /* pointer to head of result plan */ 236 237 tail = result = next = NULL; 238 239 while ((next = yanknode(&plan)) != NULL) { 240 /* 241 * if we encounter a ( expression ) then look for or's in 242 * the expr subplan. 243 */ 244 if (next->type == N_EXPR) 245 next->p_data[0] = or_squish(next->p_data[0]); 246 247 /* if we encounter a not then look for not's in the subplan */ 248 if (next->type == N_NOT) 249 next->p_data[0] = or_squish(next->p_data[0]); 250 251 /* 252 * if we encounter an or, then place our collected plan in the 253 * or's first subplan and then recursively collect the 254 * remaining stuff into the second subplan and return the or. 255 */ 256 if (next->type == N_OR) { 257 if (result == NULL) 258 errx(1, "-o: no expression before -o"); 259 next->p_data[0] = result; 260 next->p_data[1] = or_squish(plan); 261 if (next->p_data[1] == NULL) 262 errx(1, "-o: no expression after -o"); 263 return (next); 264 } 265 266 /* add the node to our result plan */ 267 if (result == NULL) 268 tail = result = next; 269 else { 270 tail->next = next; 271 tail = next; 272 } 273 tail->next = NULL; 274 } 275 return (result); 276 } 277