1 %{ 2 3 /* 4 * (C) Copyright 2014, Stephen M. Cameron. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 18 * 19 */ 20 21 #include <stdio.h> 22 #include <string.h> 23 #include <math.h> 24 25 struct parser_value_type { 26 double dval; 27 long long ival; 28 int has_dval; 29 int has_error; 30 }; 31 32 typedef union valtype { 33 struct parser_value_type v; 34 } PARSER_VALUE_TYPE; 35 36 #define YYSTYPE PARSER_VALUE_TYPE 37 38 int yyerror(__attribute__((unused)) long long *result, 39 __attribute__((unused)) double *dresult, 40 __attribute__((unused)) int *has_error, 41 __attribute__((unused)) int *units_specified, 42 __attribute__((unused)) const char *msg); 43 44 extern int yylex(void); 45 extern void yyrestart(FILE *file); 46 extern int lexer_value_is_time; 47 48 %} 49 50 %union valtype { 51 struct parser_value_type { 52 double dval; 53 long long ival; 54 int has_dval; 55 int has_error; 56 } v; 57 }; 58 59 %token <v> NUMBER 60 %token <v> BYE 61 %token <v> SUFFIX 62 %left '-' '+' 63 %right SUFFIX 64 %left '*' '/' 65 %right '^' 66 %left '%' 67 %nonassoc UMINUS 68 %parse-param { long long *result } 69 %parse-param { double *dresult } 70 %parse-param { int *has_error } 71 %parse-param { int *units_specified } 72 73 %type <v> expression 74 %% 75 76 top_level: expression { 77 *result = $1.ival; 78 *dresult = $1.dval; 79 *has_error = $1.has_error; 80 } 81 | expression error { 82 *result = $1.ival; 83 *dresult = $1.dval; 84 *has_error = 1; 85 } 86 expression: expression '+' expression { 87 if (!$1.has_dval && !$3.has_dval) 88 $$.ival = $1.ival + $3.ival; 89 else 90 $$.ival = (long long) ($1.dval + $3.dval); 91 $$.dval = $1.dval + $3.dval; 92 $$.has_error = $1.has_error || $3.has_error; 93 } 94 | expression '-' expression { 95 if (!$1.has_dval && !$3.has_dval) 96 $$.ival = $1.ival - $3.ival; 97 else 98 $$.ival = (long long) ($1.dval - $3.dval); 99 $$.dval = $1.dval - $3.dval; 100 $$.has_error = $1.has_error || $3.has_error; 101 } 102 | expression '*' expression { 103 if (!$1.has_dval && !$3.has_dval) 104 $$.ival = $1.ival * $3.ival; 105 else 106 $$.ival = (long long) ($1.dval * $3.dval); 107 $$.dval = $1.dval * $3.dval; 108 $$.has_error = $1.has_error || $3.has_error; 109 } 110 | expression '/' expression { 111 if ($3.ival == 0) 112 yyerror(0, 0, 0, 0, "divide by zero"); 113 else 114 $$.ival = $1.ival / $3.ival; 115 if ($3.dval < 1e-20 && $3.dval > -1e-20) 116 yyerror(0, 0, 0, 0, "divide by zero"); 117 else 118 $$.dval = $1.dval / $3.dval; 119 if ($3.has_dval || $1.has_dval) 120 $$.ival = (long long) $$.dval; 121 $$.has_error = $1.has_error || $3.has_error; 122 } 123 | '-' expression %prec UMINUS { 124 $$.ival = -$2.ival; 125 $$.dval = -$2.dval; 126 $$.has_error = $2.has_error; 127 } 128 | '(' expression ')' { $$ = $2; } 129 | expression SUFFIX { 130 if (!$1.has_dval && !$2.has_dval) 131 $$.ival = $1.ival * $2.ival; 132 else 133 $$.ival = (long long) $1.dval * $2.dval; 134 if ($1.has_dval || $2.has_dval) 135 $$.dval = $1.dval * $2.dval; 136 else 137 $$.dval = $1.ival * $2.ival; 138 $$.has_error = $1.has_error || $2.has_error; 139 *units_specified = 1; 140 } 141 | expression '%' expression { 142 if ($1.has_dval || $3.has_dval) 143 yyerror(0, 0, 0, 0, "modulo on floats"); 144 if ($3.ival == 0) 145 yyerror(0, 0, 0, 0, "divide by zero"); 146 else { 147 $$.ival = $1.ival % $3.ival; 148 $$.dval = $$.ival; 149 } 150 $$.has_error = $1.has_error || $3.has_error; 151 } 152 | expression '^' expression { 153 $$.has_error = $1.has_error || $3.has_error; 154 if (!$1.has_dval && !$3.has_dval) { 155 int i; 156 157 if ($3.ival == 0) { 158 $$.ival = 1; 159 } else if ($3.ival > 0) { 160 long long tmp = $1.ival; 161 $$.ival = 1.0; 162 for (i = 0; i < $3.ival; i++) 163 $$.ival *= tmp; 164 } else { 165 /* integers, 2^-3, ok, we now have doubles */ 166 double tmp; 167 if ($1.ival == 0 && $3.ival == 0) { 168 tmp = 1.0; 169 $$.has_error = 1; 170 } else { 171 double x = (double) $1.ival; 172 double y = (double) $3.ival; 173 tmp = pow(x, y); 174 } 175 $$.ival = (long long) tmp; 176 } 177 $$.dval = pow($1.dval, $3.dval); 178 } else { 179 $$.dval = pow($1.dval, $3.dval); 180 $$.ival = (long long) $$.dval; 181 } 182 } 183 | NUMBER { $$ = $1; }; 184 %% 185 #include <stdio.h> 186 187 /* Urgh. yacc and lex are kind of horrible. This is not thread safe, obviously. */ 188 static int lexer_read_offset = 0; 189 static char lexer_input_buffer[1000]; 190 191 int lexer_input(char* buffer, unsigned int *bytes_read, int bytes_requested) 192 { 193 int bytes_left = strlen(lexer_input_buffer) - lexer_read_offset; 194 195 if (bytes_requested > bytes_left ) 196 bytes_requested = bytes_left; 197 memcpy(buffer, &lexer_input_buffer[lexer_read_offset], bytes_requested); 198 *bytes_read = bytes_requested; 199 lexer_read_offset += bytes_requested; 200 return 0; 201 } 202 203 static void setup_to_parse_string(const char *string) 204 { 205 unsigned int len; 206 207 len = strlen(string); 208 if (len > sizeof(lexer_input_buffer) - 3) 209 len = sizeof(lexer_input_buffer) - 3; 210 211 strncpy(lexer_input_buffer, string, len); 212 lexer_input_buffer[len] = '\0'; 213 lexer_input_buffer[len + 1] = '\0'; /* lex/yacc want string double null terminated! */ 214 lexer_read_offset = 0; 215 } 216 217 int evaluate_arithmetic_expression(const char *buffer, long long *ival, double *dval, 218 double implied_units, int is_time) 219 { 220 int rc, units_specified = 0, has_error = 0; 221 222 lexer_value_is_time = is_time; 223 setup_to_parse_string(buffer); 224 rc = yyparse(ival, dval, &has_error, &units_specified); 225 yyrestart(NULL); 226 if (rc || has_error) { 227 *ival = 0; 228 *dval = 0; 229 has_error = 1; 230 } 231 if (!units_specified) { 232 *ival = (int) ((double) *ival * implied_units); 233 *dval = *dval * implied_units; 234 } 235 return has_error; 236 } 237 238 int yyerror(__attribute__((unused)) long long *result, 239 __attribute__((unused)) double *dresult, 240 __attribute__((unused)) int *has_error, 241 __attribute__((unused)) int *units_specified, 242 __attribute__((unused)) const char *msg) 243 { 244 /* We do not need to do anything here. */ 245 return 0; 246 } 247 248
