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 N_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 int f_expr(); 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->type == N_OPENPAREN) 98 for (tail = subplan = NULL;;) { 99 if ((next = yankexpr(planp)) == NULL) 100 err(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 N_EXPR. The ')' we found is ignored. Otherwise, 105 * we just continue to add whatever we get to our 106 * subplan. 107 */ 108 if (next->type == N_CLOSEPAREN) { 109 if (subplan == NULL) 110 errx(1, "(): empty inner expression"); 111 node->p_data[0] = subplan; 112 node->type = N_EXPR; 113 node->eval = 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 "parentheisized" plans in our search plan with "expr" nodes. 131 */ 132 PLAN * 133 paren_squish(plan) 134 PLAN *plan; /* plan with ( ) nodes */ 135 { 136 register PLAN *expr; /* pointer to next expression */ 137 register 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 it's 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->type == N_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 register PLAN *next; /* next node being processed */ 175 register PLAN *node; /* temporary node used in N_NOT processing */ 176 register PLAN *tail; /* pointer to tail of result plan */ 177 PLAN *result; /* pointer to head of result plan */ 178 179 tail = result = next = NULL; 180 181 while ((next = yanknode(&plan)) != NULL) { 182 /* 183 * if we encounter a ( expression ) then look for nots in 184 * the expr subplan. 185 */ 186 if (next->type == N_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->type == N_NOT) { 195 int notlevel = 1; 196 197 node = yanknode(&plan); 198 while (node != NULL && node->type == N_NOT) { 199 ++notlevel; 200 node = yanknode(&plan); 201 } 202 if (node == NULL) 203 errx(1, "!: no following expression"); 204 if (node->type == N_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->type == N_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 register PLAN *next; /* next node being processed */ 239 register 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->type == N_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->type == N_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->type == N_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