4 * (C) Copyright 2014, Stephen M. Cameron.
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.
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.
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
25 struct parser_value_type {
32 typedef union valtype {
33 struct parser_value_type v;
36 #define YYSTYPE PARSER_VALUE_TYPE
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);
44 extern int yylex(void);
45 extern void yyrestart(FILE *file);
50 struct parser_value_type {
67 %parse-param { long long *result }
68 %parse-param { double *dresult }
69 %parse-param { int *has_error }
70 %parse-param { int *units_specified }
75 top_level: expression {
78 *has_error = $1.has_error;
85 expression: expression '+' expression {
86 if (!$1.has_dval && !$3.has_dval)
87 $$.ival = $1.ival + $3.ival;
89 $$.ival = (long long) ($1.dval + $3.dval);
90 $$.dval = $1.dval + $3.dval;
91 $$.has_error = $1.has_error || $3.has_error;
93 | expression '-' expression {
94 if (!$1.has_dval && !$3.has_dval)
95 $$.ival = $1.ival - $3.ival;
97 $$.ival = (long long) ($1.dval - $3.dval);
98 $$.dval = $1.dval - $3.dval;
99 $$.has_error = $1.has_error || $3.has_error;
101 | expression '*' expression {
102 if (!$1.has_dval && !$3.has_dval)
103 $$.ival = $1.ival * $3.ival;
105 $$.ival = (long long) ($1.dval * $3.dval);
106 $$.dval = $1.dval * $3.dval;
107 $$.has_error = $1.has_error || $3.has_error;
109 | expression '/' expression {
111 yyerror(0, 0, 0, 0, "divide by zero");
113 $$.ival = $1.ival / $3.ival;
114 if ($3.dval < 1e-20 && $3.dval > -1e-20)
115 yyerror(0, 0, 0, 0, "divide by zero");
117 $$.dval = $1.dval / $3.dval;
118 if ($3.has_dval || $1.has_dval)
119 $$.ival = (long long) $$.dval;
120 $$.has_error = $1.has_error || $3.has_error;
122 | '-' expression %prec UMINUS {
125 $$.has_error = $2.has_error;
127 | '(' expression ')' { $$ = $2; }
128 | expression SUFFIX {
129 if (!$1.has_dval && !$2.has_dval)
130 $$.ival = $1.ival * $2.ival;
132 $$.ival = (long long) $1.dval * $2.dval;
133 if ($1.has_dval || $2.has_dval)
134 $$.dval = $1.dval * $2.dval;
136 $$.dval = $1.ival * $2.ival;
137 $$.has_error = $1.has_error || $2.has_error;
138 *units_specified = 1;
140 | expression '%' expression {
141 if ($1.has_dval || $3.has_dval)
142 yyerror(0, 0, 0, 0, "modulo on floats");
144 yyerror(0, 0, 0, 0, "divide by zero");
146 $$.ival = $1.ival % $3.ival;
149 $$.has_error = $1.has_error || $3.has_error;
151 | expression '^' expression {
152 $$.has_error = $1.has_error || $3.has_error;
153 if (!$1.has_dval && !$3.has_dval) {
158 } else if ($3.ival > 0) {
159 long long tmp = $1.ival;
161 for (i = 0; i < $3.ival; i++)
164 /* integers, 2^-3, ok, we now have doubles */
166 if ($1.ival == 0 && $3.ival == 0) {
170 double x = (double) $1.ival;
171 double y = (double) $3.ival;
174 $$.ival = (long long) tmp;
176 $$.dval = pow($1.dval, $3.dval);
178 $$.dval = pow($1.dval, $3.dval);
179 $$.ival = (long long) $$.dval;
182 | NUMBER { $$ = $1; };
186 /* Urgh. yacc and lex are kind of horrible. This is not thread safe, obviously. */
187 static int lexer_read_offset = 0;
188 static char lexer_input_buffer[1000];
190 int lexer_input(char* buffer, unsigned int *bytes_read, int bytes_requested)
192 int bytes_left = strlen(lexer_input_buffer) - lexer_read_offset;
194 if (bytes_requested > bytes_left )
195 bytes_requested = bytes_left;
196 memcpy(buffer, &lexer_input_buffer[lexer_read_offset], bytes_requested);
197 *bytes_read = bytes_requested;
198 lexer_read_offset += bytes_requested;
202 static void setup_to_parse_string(const char *string)
206 len = strlen(string);
207 if (len > sizeof(lexer_input_buffer) - 3)
208 len = sizeof(lexer_input_buffer) - 3;
210 strncpy(lexer_input_buffer, string, len);
211 lexer_input_buffer[len] = '\0';
212 lexer_input_buffer[len + 1] = '\0'; /* lex/yacc want string double null terminated! */
213 lexer_read_offset = 0;
216 int evaluate_arithmetic_expression(const char *buffer, long long *ival, double *dval,
217 double implied_units)
219 int rc, units_specified = 0, has_error = 0;
221 setup_to_parse_string(buffer);
222 rc = yyparse(ival, dval, &has_error, &units_specified);
224 if (rc || has_error) {
229 if (!units_specified) {
230 *ival = (int) ((double) *ival * implied_units);
231 *dval = *dval * implied_units;
236 int yyerror(__attribute__((unused)) long long *result,
237 __attribute__((unused)) double *dresult,
238 __attribute__((unused)) int *has_error,
239 __attribute__((unused)) int *units_specified,
240 __attribute__((unused)) const char *msg)
242 /* We do not need to do anything here. */