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
lexer_input(char * buffer,unsigned int * bytes_read,int bytes_requested)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
setup_to_parse_string(const char * string)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
evaluate_arithmetic_expression(const char * buffer,long long * ival,double * dval,double implied_units,int is_time)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
yyerror(long long * result,double * dresult,int * has_error,int * units_specified,const char * msg)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