| 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 | static char sccsid[] = "@(#)operator.c 8.1 (Berkeley) 6/6/93"; |
| 39 | #endif /* not lint */ |
| 40 | |
| 41 | #include <sys/types.h> |
| 42 | |
| 43 | #include <err.h> |
| 44 | #include <fts.h> |
| 45 | #include <stdio.h> |
| 46 | |
| 47 | #include "find.h" |
| 48 | |
| 49 | /* |
| 50 | * yanknode -- |
| 51 | * destructively removes the top from the plan |
| 52 | */ |
| 53 | static PLAN * |
| 54 | yanknode(planp) |
| 55 | PLAN **planp; /* pointer to top of plan (modified) */ |
| 56 | { |
| 57 | PLAN *node; /* top node removed from the plan */ |
| 58 | |
| 59 | if ((node = (*planp)) == NULL) |
| 60 | return (NULL); |
| 61 | (*planp) = (*planp)->next; |
| 62 | node->next = NULL; |
| 63 | return (node); |
| 64 | } |
| 65 | |
| 66 | /* |
| 67 | * yankexpr -- |
| 68 | * Removes one expression from the plan. This is used mainly by |
| 69 | * paren_squish. In comments below, an expression is either a |
| 70 | * simple node or a N_EXPR node containing a list of simple nodes. |
| 71 | */ |
| 72 | static PLAN * |
| 73 | yankexpr(planp) |
| 74 | PLAN **planp; /* pointer to top of plan (modified) */ |
| 75 | { |
| 76 | register PLAN *next; /* temp node holding subexpression results */ |
| 77 | PLAN *node; /* pointer to returned node or expression */ |
| 78 | PLAN *tail; /* pointer to tail of subplan */ |
| 79 | PLAN *subplan; /* pointer to head of ( ) expression */ |
| 80 | int f_expr(); |
| 81 | |
| 82 | /* first pull the top node from the plan */ |
| 83 | if ((node = yanknode(planp)) == NULL) |
| 84 | return (NULL); |
| 85 | |
| 86 | /* |
| 87 | * If the node is an '(' then we recursively slurp up expressions |
| 88 | * until we find its associated ')'. If it's a closing paren we |
| 89 | * just return it and unwind our recursion; all other nodes are |
| 90 | * complete expressions, so just return them. |
| 91 | */ |
| 92 | if (node->type == N_OPENPAREN) |
| 93 | for (tail = subplan = NULL;;) { |
| 94 | if ((next = yankexpr(planp)) == NULL) |
| 95 | err(1, "(: missing closing ')'"); |
| 96 | /* |
| 97 | * If we find a closing ')' we store the collected |
| 98 | * subplan in our '(' node and convert the node to |
| 99 | * a N_EXPR. The ')' we found is ignored. Otherwise, |
| 100 | * we just continue to add whatever we get to our |
| 101 | * subplan. |
| 102 | */ |
| 103 | if (next->type == N_CLOSEPAREN) { |
| 104 | if (subplan == NULL) |
| 105 | errx(1, "(): empty inner expression"); |
| 106 | node->p_data[0] = subplan; |
| 107 | node->type = N_EXPR; |
| 108 | node->eval = f_expr; |
| 109 | break; |
| 110 | } else { |
| 111 | if (subplan == NULL) |
| 112 | tail = subplan = next; |
| 113 | else { |
| 114 | tail->next = next; |
| 115 | tail = next; |
| 116 | } |
| 117 | tail->next = NULL; |
| 118 | } |
| 119 | } |
| 120 | return (node); |
| 121 | } |
| 122 | |
| 123 | /* |
| 124 | * paren_squish -- |
| 125 | * replaces "parentheisized" plans in our search plan with "expr" nodes. |
| 126 | */ |
| 127 | PLAN * |
| 128 | paren_squish(plan) |
| 129 | PLAN *plan; /* plan with ( ) nodes */ |
| 130 | { |
| 131 | register PLAN *expr; /* pointer to next expression */ |
| 132 | register PLAN *tail; /* pointer to tail of result plan */ |
| 133 | PLAN *result; /* pointer to head of result plan */ |
| 134 | |
| 135 | result = tail = NULL; |
| 136 | |
| 137 | /* |
| 138 | * the basic idea is to have yankexpr do all our work and just |
| 139 | * collect it's results together. |
| 140 | */ |
| 141 | while ((expr = yankexpr(&plan)) != NULL) { |
| 142 | /* |
| 143 | * if we find an unclaimed ')' it means there is a missing |
| 144 | * '(' someplace. |
| 145 | */ |
| 146 | if (expr->type == N_CLOSEPAREN) |
| 147 | errx(1, "): no beginning '('"); |
| 148 | |
| 149 | /* add the expression to our result plan */ |
| 150 | if (result == NULL) |
| 151 | tail = result = expr; |
| 152 | else { |
| 153 | tail->next = expr; |
| 154 | tail = expr; |
| 155 | } |
| 156 | tail->next = NULL; |
| 157 | } |
| 158 | return (result); |
| 159 | } |
| 160 | |
| 161 | /* |
| 162 | * not_squish -- |
| 163 | * compresses "!" expressions in our search plan. |
| 164 | */ |
| 165 | PLAN * |
| 166 | not_squish(plan) |
| 167 | PLAN *plan; /* plan to process */ |
| 168 | { |
| 169 | register PLAN *next; /* next node being processed */ |
| 170 | register PLAN *node; /* temporary node used in N_NOT processing */ |
| 171 | register PLAN *tail; /* pointer to tail of result plan */ |
| 172 | PLAN *result; /* pointer to head of result plan */ |
| 173 | |
| 174 | tail = result = next = NULL; |
| 175 | |
| 176 | while ((next = yanknode(&plan)) != NULL) { |
| 177 | /* |
| 178 | * if we encounter a ( expression ) then look for nots in |
| 179 | * the expr subplan. |
| 180 | */ |
| 181 | if (next->type == N_EXPR) |
| 182 | next->p_data[0] = not_squish(next->p_data[0]); |
| 183 | |
| 184 | /* |
| 185 | * if we encounter a not, then snag the next node and place |
| 186 | * it in the not's subplan. As an optimization we compress |
| 187 | * several not's to zero or one not. |
| 188 | */ |
| 189 | if (next->type == N_NOT) { |
| 190 | int notlevel = 1; |
| 191 | |
| 192 | node = yanknode(&plan); |
| 193 | while (node->type == N_NOT) { |
| 194 | ++notlevel; |
| 195 | node = yanknode(&plan); |
| 196 | } |
| 197 | if (node == NULL) |
| 198 | errx(1, "!: no following expression"); |
| 199 | if (node->type == N_OR) |
| 200 | errx(1, "!: nothing between ! and -o"); |
| 201 | if (notlevel % 2 != 1) |
| 202 | next = node; |
| 203 | else |
| 204 | next->p_data[0] = node; |
| 205 | } |
| 206 | |
| 207 | /* add the node to our result plan */ |
| 208 | if (result == NULL) |
| 209 | tail = result = next; |
| 210 | else { |
| 211 | tail->next = next; |
| 212 | tail = next; |
| 213 | } |
| 214 | tail->next = NULL; |
| 215 | } |
| 216 | return (result); |
| 217 | } |
| 218 | |
| 219 | /* |
| 220 | * or_squish -- |
| 221 | * compresses -o expressions in our search plan. |
| 222 | */ |
| 223 | PLAN * |
| 224 | or_squish(plan) |
| 225 | PLAN *plan; /* plan with ors to be squished */ |
| 226 | { |
| 227 | register PLAN *next; /* next node being processed */ |
| 228 | register PLAN *tail; /* pointer to tail of result plan */ |
| 229 | PLAN *result; /* pointer to head of result plan */ |
| 230 | |
| 231 | tail = result = next = NULL; |
| 232 | |
| 233 | while ((next = yanknode(&plan)) != NULL) { |
| 234 | /* |
| 235 | * if we encounter a ( expression ) then look for or's in |
| 236 | * the expr subplan. |
| 237 | */ |
| 238 | if (next->type == N_EXPR) |
| 239 | next->p_data[0] = or_squish(next->p_data[0]); |
| 240 | |
| 241 | /* if we encounter a not then look for not's in the subplan */ |
| 242 | if (next->type == N_NOT) |
| 243 | next->p_data[0] = or_squish(next->p_data[0]); |
| 244 | |
| 245 | /* |
| 246 | * if we encounter an or, then place our collected plan in the |
| 247 | * or's first subplan and then recursively collect the |
| 248 | * remaining stuff into the second subplan and return the or. |
| 249 | */ |
| 250 | if (next->type == N_OR) { |
| 251 | if (result == NULL) |
| 252 | errx(1, "-o: no expression before -o"); |
| 253 | next->p_data[0] = result; |
| 254 | next->p_data[1] = or_squish(plan); |
| 255 | if (next->p_data[1] == NULL) |
| 256 | errx(1, "-o: no expression after -o"); |
| 257 | return (next); |
| 258 | } |
| 259 | |
| 260 | /* add the node to our result plan */ |
| 261 | if (result == NULL) |
| 262 | tail = result = next; |
| 263 | else { |
| 264 | tail->next = next; |
| 265 | tail = next; |
| 266 | } |
| 267 | tail->next = NULL; |
| 268 | } |
| 269 | return (result); |
| 270 | } |