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 *bye, const char *msg);
42 extern int yylex(void);
43 extern void yyrestart(FILE *file);
48 struct parser_value_type {
65 %parse-param { long long *result }
66 %parse-param { double *dresult }
67 %parse-param { int *has_error }
68 %parse-param { int *bye }
73 top_level: expression {
76 *has_error = $1.has_error;
83 expression: expression '+' expression {
84 if (!$1.has_dval && !$3.has_dval)
85 $$.ival = $1.ival + $3.ival;
87 $$.ival = (long long) ($1.dval + $3.dval);
88 $$.dval = $1.dval + $3.dval;
89 $$.has_error = $1.has_error || $3.has_error;
91 | expression '-' expression {
92 if (!$1.has_dval && !$3.has_dval)
93 $$.ival = $1.ival - $3.ival;
95 $$.ival = (long long) ($1.dval - $3.dval);
96 $$.dval = $1.dval - $3.dval;
97 $$.has_error = $1.has_error || $3.has_error;
99 | expression '*' expression {
100 if (!$1.has_dval && !$3.has_dval)
101 $$.ival = $1.ival * $3.ival;
103 $$.ival = (long long) ($1.dval * $3.dval);
104 $$.dval = $1.dval * $3.dval;
105 $$.has_error = $1.has_error || $3.has_error;
107 | expression '/' expression {
109 yyerror(0, 0, 0, 0, "divide by zero");
111 $$.ival = $1.ival / $3.ival;
112 if ($3.dval < 1e-20 && $3.dval > -1e-20)
113 yyerror(0, 0, 0, 0, "divide by zero");
115 $$.dval = $1.dval / $3.dval;
116 if ($3.has_dval || $1.has_dval)
117 $$.ival = (long long) $$.dval;
118 $$.has_error = $1.has_error || $3.has_error;
120 | '-' expression %prec UMINUS {
123 $$.has_error = $2.has_error;
125 | '(' expression ')' { $$ = $2; }
126 | expression SUFFIX {
127 if (!$1.has_dval && !$2.has_dval)
128 $$.ival = $1.ival * $2.ival;
130 $$.ival = (long long) $1.dval * $2.dval;
131 if ($1.has_dval || $2.has_dval)
132 $$.dval = $1.dval * $2.dval;
134 $$.dval = $1.ival * $2.ival;
135 $$.has_error = $1.has_error || $2.has_error;
137 | expression '%' expression {
138 if ($1.has_dval || $3.has_dval)
139 yyerror(0, 0, 0, 0, "modulo on floats");
141 yyerror(0, 0, 0, 0, "divide by zero");
143 $$.ival = $1.ival % $3.ival;
146 $$.has_error = $1.has_error || $3.has_error;
148 | expression '^' expression {
149 $$.has_error = $1.has_error || $3.has_error;
150 if (!$1.has_dval && !$3.has_dval) {
155 } else if ($3.ival > 0) {
156 long long tmp = $1.ival;
158 for (i = 0; i < $3.ival; i++)
161 /* integers, 2^-3, ok, we now have doubles */
163 if ($1.ival == 0 && $3.ival == 0) {
167 double x = (double) $1.ival;
168 double y = (double) $3.ival;
171 $$.ival = (long long) tmp;
173 $$.dval = pow($1.dval, $3.dval);
175 $$.dval = pow($1.dval, $3.dval);
176 $$.ival = (long long) $$.dval;
179 | NUMBER { $$ = $1; }
180 | BYE { $$ = $1; *bye = 1; };
184 /* Urgh. yacc and lex are kind of horrible. This is not thread safe, obviously. */
185 static int lexer_read_offset = 0;
186 static char lexer_input_buffer[1000];
188 int lexer_input(char* buffer, int *bytes_read, int bytes_requested)
190 int bytes_left = strlen(lexer_input_buffer) - lexer_read_offset;
192 if (bytes_requested > bytes_left )
193 bytes_requested = bytes_left;
194 memcpy(buffer, &lexer_input_buffer[lexer_read_offset], bytes_requested);
195 *bytes_read = bytes_requested;
196 lexer_read_offset += bytes_requested;
200 static void setup_to_parse_string(const char *string)
204 len = strlen(string);
205 if (len > sizeof(lexer_input_buffer) - 3)
206 len = sizeof(lexer_input_buffer) - 3;
208 strncpy(lexer_input_buffer, string, len);
209 lexer_input_buffer[len] = '\0';
210 lexer_input_buffer[len + 1] = '\0'; /* lex/yacc want string double null terminated! */
211 lexer_read_offset = 0;
214 int evaluate_arithmetic_expression(const char *buffer, long long *ival, double *dval)
216 int rc, bye = 0, has_error = 0;
218 setup_to_parse_string(buffer);
219 rc = yyparse(ival, dval, &has_error, &bye);
221 if (rc || bye || has_error) {
229 int yyerror(__attribute__((unused)) long long *result,
230 __attribute__((unused)) double *dresult,
231 __attribute__((unused)) int *has_error,
232 __attribute__((unused)) int *bye,
233 __attribute__((unused)) const char *msg)
235 /* We do not need to do anything here. */