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
24 struct parser_value_type {
31 typedef union valtype {
32 struct parser_value_type v;
35 #define YYSTYPE PARSER_VALUE_TYPE
37 int yyerror(__attribute__((unused)) long long *result,
38 __attribute__((unused)) double *dresult,
39 __attribute__((unused)) int *has_error,
40 __attribute__((unused)) int *units_specified,
41 __attribute__((unused)) const char *msg);
43 extern int yylex(void);
44 extern void yyrestart(FILE *file);
49 struct parser_value_type {
66 %parse-param { long long *result }
67 %parse-param { double *dresult }
68 %parse-param { int *has_error }
69 %parse-param { int *units_specified }
74 top_level: expression {
77 *has_error = $1.has_error;
84 expression: expression '+' expression {
85 if (!$1.has_dval && !$3.has_dval)
86 $$.ival = $1.ival + $3.ival;
88 $$.ival = (long long) ($1.dval + $3.dval);
89 $$.dval = $1.dval + $3.dval;
90 $$.has_error = $1.has_error || $3.has_error;
92 | expression '-' expression {
93 if (!$1.has_dval && !$3.has_dval)
94 $$.ival = $1.ival - $3.ival;
96 $$.ival = (long long) ($1.dval - $3.dval);
97 $$.dval = $1.dval - $3.dval;
98 $$.has_error = $1.has_error || $3.has_error;
100 | expression '*' expression {
101 if (!$1.has_dval && !$3.has_dval)
102 $$.ival = $1.ival * $3.ival;
104 $$.ival = (long long) ($1.dval * $3.dval);
105 $$.dval = $1.dval * $3.dval;
106 $$.has_error = $1.has_error || $3.has_error;
108 | expression '/' expression {
110 yyerror(0, 0, 0, 0, "divide by zero");
112 $$.ival = $1.ival / $3.ival;
113 if ($3.dval < 1e-20 && $3.dval > -1e-20)
114 yyerror(0, 0, 0, 0, "divide by zero");
116 $$.dval = $1.dval / $3.dval;
117 if ($3.has_dval || $1.has_dval)
118 $$.ival = (long long) $$.dval;
119 $$.has_error = $1.has_error || $3.has_error;
121 | '-' expression %prec UMINUS {
124 $$.has_error = $2.has_error;
126 | '(' expression ')' { $$ = $2; }
127 | expression SUFFIX {
128 if (!$1.has_dval && !$2.has_dval)
129 $$.ival = $1.ival * $2.ival;
131 $$.ival = (long long) $1.dval * $2.dval;
132 if ($1.has_dval || $2.has_dval)
133 $$.dval = $1.dval * $2.dval;
135 $$.dval = $1.ival * $2.ival;
136 $$.has_error = $1.has_error || $2.has_error;
137 *units_specified = 1;
139 | expression '%' expression {
140 if ($1.has_dval || $3.has_dval)
141 yyerror(0, 0, 0, 0, "modulo on floats");
143 yyerror(0, 0, 0, 0, "divide by zero");
145 $$.ival = $1.ival % $3.ival;
148 $$.has_error = $1.has_error || $3.has_error;
150 | expression '^' expression {
151 $$.has_error = $1.has_error || $3.has_error;
152 if (!$1.has_dval && !$3.has_dval) {
157 } else if ($3.ival > 0) {
158 long long tmp = $1.ival;
160 for (i = 0; i < $3.ival; i++)
163 /* integers, 2^-3, ok, we now have doubles */
165 if ($1.ival == 0 && $3.ival == 0) {
169 double x = (double) $1.ival;
170 double y = (double) $3.ival;
173 $$.ival = (long long) tmp;
175 $$.dval = pow($1.dval, $3.dval);
177 $$.dval = pow($1.dval, $3.dval);
178 $$.ival = (long long) $$.dval;
181 | NUMBER { $$ = $1; };
185 /* Urgh. yacc and lex are kind of horrible. This is not thread safe, obviously. */
186 static int lexer_read_offset = 0;
187 static char lexer_input_buffer[1000];
189 int lexer_input(char* buffer, int *bytes_read, int bytes_requested)
191 int bytes_left = strlen(lexer_input_buffer) - lexer_read_offset;
193 if (bytes_requested > bytes_left )
194 bytes_requested = bytes_left;
195 memcpy(buffer, &lexer_input_buffer[lexer_read_offset], bytes_requested);
196 *bytes_read = bytes_requested;
197 lexer_read_offset += bytes_requested;
201 static void setup_to_parse_string(const char *string)
205 len = strlen(string);
206 if (len > sizeof(lexer_input_buffer) - 3)
207 len = sizeof(lexer_input_buffer) - 3;
209 strncpy(lexer_input_buffer, string, len);
210 lexer_input_buffer[len] = '\0';
211 lexer_input_buffer[len + 1] = '\0'; /* lex/yacc want string double null terminated! */
212 lexer_read_offset = 0;
215 int evaluate_arithmetic_expression(const char *buffer, long long *ival, double *dval,
216 double implied_units)
218 int rc, units_specified = 0, has_error = 0;
220 setup_to_parse_string(buffer);
221 rc = yyparse(ival, dval, &has_error, &units_specified);
223 if (rc || has_error) {
228 if (!units_specified) {
229 *ival = (int) ((double) *ival * implied_units);
230 *dval = *dval * implied_units;
235 int yyerror(__attribute__((unused)) long long *result,
236 __attribute__((unused)) double *dresult,
237 __attribute__((unused)) int *has_error,
238 __attribute__((unused)) int *units_specified,
239 __attribute__((unused)) const char *msg)
241 /* We do not need to do anything here. */