1 /* 2 * Mach Operating System 3 * Copyright (c) 1991,1990 Carnegie Mellon University 4 * All Rights Reserved. 5 * 6 * Permission to use, copy, modify and distribute this software and its 7 * documentation is hereby granted, provided that both the copyright 8 * notice and this permission notice appear in all copies of the 9 * software, derivative works or modified versions, and any portions 10 * thereof, and that both notices appear in supporting documentation. 11 * 12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS 13 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR 14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 15 * 16 * Carnegie Mellon requests users of this software to return to 17 * 18 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 19 * School of Computer Science 20 * Carnegie Mellon University 21 * Pittsburgh PA 15213-3890 22 * 23 * any improvements or extensions that they make and grant Carnegie the 24 * rights to redistribute these changes. 25 * 26 * $Id$ 27 */ 28 29 /* 30 * Author: David B. Golub, Carnegie Mellon University 31 * Date: 7/90 32 */ 33 /* 34 * Lexical analyzer. 35 */ 36 #include <ddb/db_lex.h> 37 38 char db_line[120]; 39 char * db_lp, *db_endlp; 40 41 int 42 db_read_line() 43 { 44 int i; 45 46 i = db_readline(db_line, sizeof(db_line)); 47 if (i == 0) 48 return (0); /* EOI */ 49 db_lp = db_line; 50 db_endlp = db_lp + i; 51 return (i); 52 } 53 54 void 55 db_flush_line() 56 { 57 db_lp = db_line; 58 db_endlp = db_line; 59 } 60 61 int db_look_char = 0; 62 63 int 64 db_read_char() 65 { 66 int c; 67 68 if (db_look_char != 0) { 69 c = db_look_char; 70 db_look_char = 0; 71 } 72 else if (db_lp >= db_endlp) 73 c = -1; 74 else 75 c = *db_lp++; 76 return (c); 77 } 78 79 void 80 db_unread_char(c) 81 { 82 db_look_char = c; 83 } 84 85 int db_look_token = 0; 86 87 void 88 db_unread_token(t) 89 int t; 90 { 91 db_look_token = t; 92 } 93 94 int 95 db_read_token() 96 { 97 int t; 98 99 if (db_look_token) { 100 t = db_look_token; 101 db_look_token = 0; 102 } 103 else 104 t = db_lex(); 105 return (t); 106 } 107 108 int db_tok_number; 109 char db_tok_string[TOK_STRING_SIZE]; 110 111 int db_radix = 16; 112 113 void 114 db_flush_lex() 115 { 116 db_flush_line(); 117 db_look_char = 0; 118 db_look_token = 0; 119 } 120 121 int 122 db_lex() 123 { 124 int c; 125 126 c = db_read_char(); 127 while (c <= ' ' || c > '~') { 128 if (c == '\n' || c == -1) 129 return (tEOL); 130 c = db_read_char(); 131 } 132 133 if (c >= '0' && c <= '9') { 134 /* number */ 135 int r, digit; 136 137 if (c > '0') 138 r = db_radix; 139 else { 140 c = db_read_char(); 141 if (c == 'O' || c == 'o') 142 r = 8; 143 else if (c == 'T' || c == 't') 144 r = 10; 145 else if (c == 'X' || c == 'x') 146 r = 16; 147 else { 148 r = db_radix; 149 db_unread_char(c); 150 } 151 c = db_read_char(); 152 } 153 db_tok_number = 0; 154 for (;;) { 155 if (c >= '0' && c <= ((r == 8) ? '7' : '9')) 156 digit = c - '0'; 157 else if (r == 16 && ((c >= 'A' && c <= 'F') || 158 (c >= 'a' && c <= 'f'))) { 159 if (c >= 'a') 160 digit = c - 'a' + 10; 161 else if (c >= 'A') 162 digit = c - 'A' + 10; 163 } 164 else 165 break; 166 db_tok_number = db_tok_number * r + digit; 167 c = db_read_char(); 168 } 169 if ((c >= '0' && c <= '9') || 170 (c >= 'A' && c <= 'Z') || 171 (c >= 'a' && c <= 'z') || 172 (c == '_')) 173 { 174 db_error("Bad character in number\n"); 175 db_flush_lex(); 176 return (tEOF); 177 } 178 db_unread_char(c); 179 return (tNUMBER); 180 } 181 if ((c >= 'A' && c <= 'Z') || 182 (c >= 'a' && c <= 'z') || 183 c == '_' || c == '\\') 184 { 185 /* string */ 186 char *cp; 187 188 cp = db_tok_string; 189 if (c == '\\') { 190 c = db_read_char(); 191 if (c == '\n' || c == -1) 192 db_error("Bad escape\n"); 193 } 194 *cp++ = c; 195 while (1) { 196 c = db_read_char(); 197 if ((c >= 'A' && c <= 'Z') || 198 (c >= 'a' && c <= 'z') || 199 (c >= '0' && c <= '9') || 200 c == '_' || c == '\\' || c == ':') 201 { 202 if (c == '\\') { 203 c = db_read_char(); 204 if (c == '\n' || c == -1) 205 db_error("Bad escape\n"); 206 } 207 *cp++ = c; 208 if (cp == db_tok_string+sizeof(db_tok_string)) { 209 db_error("String too long\n"); 210 db_flush_lex(); 211 return (tEOF); 212 } 213 continue; 214 } 215 else { 216 *cp = '\0'; 217 break; 218 } 219 } 220 db_unread_char(c); 221 return (tIDENT); 222 } 223 224 switch (c) { 225 case '+': 226 return (tPLUS); 227 case '-': 228 return (tMINUS); 229 case '.': 230 c = db_read_char(); 231 if (c == '.') 232 return (tDOTDOT); 233 db_unread_char(c); 234 return (tDOT); 235 case '*': 236 return (tSTAR); 237 case '/': 238 return (tSLASH); 239 case '=': 240 return (tEQ); 241 case '%': 242 return (tPCT); 243 case '#': 244 return (tHASH); 245 case '(': 246 return (tLPAREN); 247 case ')': 248 return (tRPAREN); 249 case ',': 250 return (tCOMMA); 251 case '"': 252 return (tDITTO); 253 case '$': 254 return (tDOLLAR); 255 case '!': 256 return (tEXCL); 257 case '<': 258 c = db_read_char(); 259 if (c == '<') 260 return (tSHIFT_L); 261 db_unread_char(c); 262 break; 263 case '>': 264 c = db_read_char(); 265 if (c == '>') 266 return (tSHIFT_R); 267 db_unread_char(c); 268 break; 269 case -1: 270 return (tEOF); 271 } 272 db_printf("Bad character\n"); 273 db_flush_lex(); 274 return (tEOF); 275 } 276