1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 3 * 4 * Copyright (c) 1985 Sun Microsystems, Inc. 5 * Copyright (c) 1980, 1993 6 * The Regents of the University of California. All rights reserved. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)parse.c 8.1 (Berkeley) 6/6/93 34 * $FreeBSD: head/usr.bin/indent/parse.c 337651 2018-08-11 19:20:06Z pstef $ 35 */ 36 37 #include <err.h> 38 #include <stdio.h> 39 #include "indent_globs.h" 40 #include "indent_codes.h" 41 #include "indent.h" 42 43 /* Globals */ 44 int break_comma; 45 float case_ind; 46 47 static void reduce(void); 48 49 void 50 parse(int tk) /* tk: the code for the construct scanned */ 51 { 52 int i; 53 54 #ifdef debug 55 printf("%2d - %s\n", tk, token); 56 #endif 57 58 while (ps.p_stack[ps.tos] == ifhead && tk != elselit) { 59 /* true if we have an if without an else */ 60 ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= stmt 61 * reduction */ 62 reduce(); /* see if this allows any reduction */ 63 } 64 65 66 switch (tk) { /* go on and figure out what to do with the 67 * input */ 68 69 case decl: /* scanned a declaration word */ 70 ps.search_brace = opt.btype_2; 71 /* indicate that following brace should be on same line */ 72 if (ps.p_stack[ps.tos] != decl) { /* only put one declaration 73 * onto stack */ 74 break_comma = true; /* while in declaration, newline should be 75 * forced after comma */ 76 ps.p_stack[++ps.tos] = decl; 77 ps.il[ps.tos] = ps.i_l_follow; 78 79 if (opt.ljust_decl) {/* only do if we want left justified 80 * declarations */ 81 ps.ind_level = 0; 82 for (i = ps.tos - 1; i > 0; --i) 83 if (ps.p_stack[i] == decl) 84 ++ps.ind_level; /* indentation is number of 85 * declaration levels deep we are */ 86 ps.i_l_follow = ps.ind_level; 87 } 88 } 89 break; 90 91 case ifstmt: /* scanned if (...) */ 92 if (ps.p_stack[ps.tos] == elsehead && opt.else_if) /* "else if ..." */ 93 /* 94 * Note that the stack pointer here is decremented, effectively 95 * reducing "else if" to "if". This saves a lot of stack space 96 * in case of a long "if-else-if ... else-if" sequence. 97 */ 98 ps.i_l_follow = ps.il[ps.tos--]; 99 /* the rest is the same as for dolit and forstmt */ 100 /* FALLTHROUGH */ 101 case dolit: /* 'do' */ 102 case forstmt: /* for (...) */ 103 ps.p_stack[++ps.tos] = tk; 104 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 105 ++ps.i_l_follow; /* subsequent statements should be indented 1 */ 106 ps.search_brace = opt.btype_2; 107 break; 108 109 case lbrace: /* scanned { */ 110 break_comma = false; /* don't break comma in an initial list */ 111 if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl 112 || ps.p_stack[ps.tos] == stmtl) 113 ++ps.i_l_follow; /* it is a random, isolated stmt group or a 114 * declaration */ 115 else { 116 if (s_code == e_code) { 117 /* 118 * only do this if there is nothing on the line 119 */ 120 --ps.ind_level; 121 /* 122 * it is a group as part of a while, for, etc. 123 */ 124 if (ps.p_stack[ps.tos] == swstmt && opt.case_indent >= 1) 125 --ps.ind_level; 126 /* 127 * for a switch, brace should be two levels out from the code 128 */ 129 } 130 } 131 132 ps.p_stack[++ps.tos] = lbrace; 133 ps.il[ps.tos] = ps.ind_level; 134 ps.p_stack[++ps.tos] = stmt; 135 /* allow null stmt between braces */ 136 ps.il[ps.tos] = ps.i_l_follow; 137 break; 138 139 case whilestmt: /* scanned while (...) */ 140 if (ps.p_stack[ps.tos] == dohead) { 141 /* it is matched with do stmt */ 142 ps.ind_level = ps.i_l_follow = ps.il[ps.tos]; 143 ps.p_stack[++ps.tos] = whilestmt; 144 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 145 } 146 else { /* it is a while loop */ 147 ps.p_stack[++ps.tos] = whilestmt; 148 ps.il[ps.tos] = ps.i_l_follow; 149 ++ps.i_l_follow; 150 ps.search_brace = opt.btype_2; 151 } 152 153 break; 154 155 case elselit: /* scanned an else */ 156 157 if (ps.p_stack[ps.tos] != ifhead) 158 diag2(1, "Unmatched 'else'"); 159 else { 160 ps.ind_level = ps.il[ps.tos]; /* indentation for else should 161 * be same as for if */ 162 ps.i_l_follow = ps.ind_level + 1; /* everything following should 163 * be in 1 level */ 164 ps.p_stack[ps.tos] = elsehead; 165 /* remember if with else */ 166 ps.search_brace = opt.btype_2 | opt.else_if; 167 } 168 break; 169 170 case rbrace: /* scanned a } */ 171 /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */ 172 if (ps.tos > 0 && ps.p_stack[ps.tos - 1] == lbrace) { 173 ps.ind_level = ps.i_l_follow = ps.il[--ps.tos]; 174 ps.p_stack[ps.tos] = stmt; 175 } 176 else 177 diag2(1, "Statement nesting error"); 178 break; 179 180 case swstmt: /* had switch (...) */ 181 ps.p_stack[++ps.tos] = swstmt; 182 ps.cstk[ps.tos] = case_ind; 183 /* save current case indent level */ 184 ps.il[ps.tos] = ps.i_l_follow; 185 case_ind = ps.i_l_follow + opt.case_indent; /* cases should be one 186 * level down from 187 * switch */ 188 ps.i_l_follow += opt.case_indent + 1; /* statements should be two 189 * levels in */ 190 ps.search_brace = opt.btype_2; 191 break; 192 193 case semicolon: /* this indicates a simple stmt */ 194 break_comma = false; /* turn off flag to break after commas in a 195 * declaration */ 196 ps.p_stack[++ps.tos] = stmt; 197 ps.il[ps.tos] = ps.ind_level; 198 break; 199 200 default: /* this is an error */ 201 diag2(1, "Unknown code to parser"); 202 return; 203 204 205 } /* end of switch */ 206 207 if (ps.tos >= STACKSIZE - 1) 208 errx(1, "Parser stack overflow"); 209 210 reduce(); /* see if any reduction can be done */ 211 212 #ifdef debug 213 for (i = 1; i <= ps.tos; ++i) 214 printf("(%d %d)", ps.p_stack[i], ps.il[i]); 215 printf("\n"); 216 #endif 217 218 return; 219 } 220 221 /* 222 * NAME: reduce 223 * 224 * FUNCTION: Implements the reduce part of the parsing algorithm 225 * 226 * ALGORITHM: The following reductions are done. Reductions are repeated 227 * until no more are possible. 228 * 229 * Old TOS New TOS 230 * <stmt> <stmt> <stmtl> 231 * <stmtl> <stmt> <stmtl> 232 * do <stmt> "dostmt" 233 * if <stmt> "ifstmt" 234 * switch <stmt> <stmt> 235 * decl <stmt> <stmt> 236 * "ifelse" <stmt> <stmt> 237 * for <stmt> <stmt> 238 * while <stmt> <stmt> 239 * "dostmt" while <stmt> 240 * 241 * On each reduction, ps.i_l_follow (the indentation for the following line) 242 * is set to the indentation level associated with the old TOS. 243 * 244 * PARAMETERS: None 245 * 246 * RETURNS: Nothing 247 * 248 * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos = 249 * 250 * CALLS: None 251 * 252 * CALLED BY: parse 253 * 254 * HISTORY: initial coding November 1976 D A Willcox of CAC 255 * 256 */ 257 /*----------------------------------------------*\ 258 | REDUCTION PHASE | 259 \*----------------------------------------------*/ 260 static void 261 reduce(void) 262 { 263 int i; 264 265 for (;;) { /* keep looping until there is nothing left to 266 * reduce */ 267 268 switch (ps.p_stack[ps.tos]) { 269 270 case stmt: 271 switch (ps.p_stack[ps.tos - 1]) { 272 273 case stmt: 274 case stmtl: 275 /* stmtl stmt or stmt stmt */ 276 ps.p_stack[--ps.tos] = stmtl; 277 break; 278 279 case dolit: /* <do> <stmt> */ 280 ps.p_stack[--ps.tos] = dohead; 281 ps.i_l_follow = ps.il[ps.tos]; 282 break; 283 284 case ifstmt: 285 /* <if> <stmt> */ 286 ps.p_stack[--ps.tos] = ifhead; 287 for (i = ps.tos - 1; 288 ( 289 ps.p_stack[i] != stmt 290 && 291 ps.p_stack[i] != stmtl 292 && 293 ps.p_stack[i] != lbrace 294 ); 295 --i); 296 ps.i_l_follow = ps.il[i]; 297 /* 298 * for the time being, we will assume that there is no else on 299 * this if, and set the indentation level accordingly. If an 300 * else is scanned, it will be fixed up later 301 */ 302 break; 303 304 case swstmt: 305 /* <switch> <stmt> */ 306 case_ind = ps.cstk[ps.tos - 1]; 307 /* FALLTHROUGH */ 308 case decl: /* finish of a declaration */ 309 case elsehead: 310 /* <<if> <stmt> else> <stmt> */ 311 case forstmt: 312 /* <for> <stmt> */ 313 case whilestmt: 314 /* <while> <stmt> */ 315 ps.p_stack[--ps.tos] = stmt; 316 ps.i_l_follow = ps.il[ps.tos]; 317 break; 318 319 default: /* <anything else> <stmt> */ 320 return; 321 322 } /* end of section for <stmt> on top of stack */ 323 break; 324 325 case whilestmt: /* while (...) on top */ 326 if (ps.p_stack[ps.tos - 1] == dohead) { 327 /* it is termination of a do while */ 328 ps.tos -= 2; 329 break; 330 } 331 else 332 return; 333 334 default: /* anything else on top */ 335 return; 336 337 } 338 } 339 } 340