| 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 | |
| 24 | struct parser_value_type { |
| 25 | double dval; |
| 26 | long long ival; |
| 27 | int has_dval; |
| 28 | int has_error; |
| 29 | }; |
| 30 | |
| 31 | typedef union valtype { |
| 32 | struct parser_value_type v; |
| 33 | } PARSER_VALUE_TYPE; |
| 34 | |
| 35 | #define YYSTYPE PARSER_VALUE_TYPE |
| 36 | |
| 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); |
| 41 | |
| 42 | extern int yylex(void); |
| 43 | extern void yyrestart(FILE *file); |
| 44 | |
| 45 | %} |
| 46 | |
| 47 | %union valtype { |
| 48 | struct parser_value_type { |
| 49 | double dval; |
| 50 | long long ival; |
| 51 | int has_dval; |
| 52 | int has_error; |
| 53 | } v; |
| 54 | }; |
| 55 | |
| 56 | %token <v> NUMBER |
| 57 | %token <v> BYE |
| 58 | %token <v> SUFFIX |
| 59 | %left '-' '+' |
| 60 | %left '*' '/' |
| 61 | %nonassoc UMINUS |
| 62 | %parse-param { long long *result } |
| 63 | %parse-param { double *dresult } |
| 64 | %parse-param { int *has_error } |
| 65 | %parse-param { int *bye } |
| 66 | |
| 67 | %type <v> expression |
| 68 | %% |
| 69 | |
| 70 | top_level: expression { |
| 71 | *result = $1.ival; |
| 72 | *dresult = $1.dval; |
| 73 | *has_error = $1.has_error; |
| 74 | } |
| 75 | | expression error { |
| 76 | *result = $1.ival; |
| 77 | *dresult = $1.dval; |
| 78 | *has_error = 1; |
| 79 | } |
| 80 | expression: expression '+' expression { |
| 81 | if (!$1.has_dval && !$3.has_dval) |
| 82 | $$.ival = $1.ival + $3.ival; |
| 83 | else |
| 84 | $$.ival = (long long) ($1.dval + $3.dval); |
| 85 | $$.dval = $1.dval + $3.dval; |
| 86 | $$.has_error = $1.has_error || $3.has_error; |
| 87 | } |
| 88 | | expression '-' expression { |
| 89 | if (!$1.has_dval && !$3.has_dval) |
| 90 | $$.ival = $1.ival - $3.ival; |
| 91 | else |
| 92 | $$.ival = (long long) ($1.dval - $3.dval); |
| 93 | $$.dval = $1.dval - $3.dval; |
| 94 | $$.has_error = $1.has_error || $3.has_error; |
| 95 | } |
| 96 | | expression '*' expression { |
| 97 | if (!$1.has_dval && !$3.has_dval) |
| 98 | $$.ival = $1.ival * $3.ival; |
| 99 | else |
| 100 | $$.ival = (long long) ($1.dval * $3.dval); |
| 101 | $$.dval = $1.dval * $3.dval; |
| 102 | $$.has_error = $1.has_error || $3.has_error; |
| 103 | } |
| 104 | | expression '/' expression { |
| 105 | if ($3.ival == 0) |
| 106 | yyerror(0, 0, 0, 0, "divide by zero"); |
| 107 | else |
| 108 | $$.ival = $1.ival / $3.ival; |
| 109 | if ($3.dval < 1e-20 && $3.dval > -1e-20) |
| 110 | yyerror(0, 0, 0, 0, "divide by zero"); |
| 111 | else |
| 112 | $$.dval = $1.dval / $3.dval; |
| 113 | if ($3.has_dval || $1.has_dval) |
| 114 | $$.ival = (long long) $$.dval; |
| 115 | $$.has_error = $1.has_error || $3.has_error; |
| 116 | } |
| 117 | | '-' expression %prec UMINUS { |
| 118 | $$.ival = -$2.ival; |
| 119 | $$.dval = -$2.dval; |
| 120 | $$.has_error = $2.has_error; |
| 121 | } |
| 122 | | '(' expression ')' { $$ = $2; } |
| 123 | | expression SUFFIX { |
| 124 | if (!$1.has_dval && !$2.has_dval) |
| 125 | $$.ival = $1.ival * $2.ival; |
| 126 | else |
| 127 | $$.ival = (long long) $1.dval * $2.dval; |
| 128 | if ($1.has_dval || $2.has_dval) |
| 129 | $$.dval = $1.dval * $2.dval; |
| 130 | else |
| 131 | $$.dval = $1.ival * $2.ival; |
| 132 | $$.has_error = $1.has_error || $2.has_error; |
| 133 | } |
| 134 | | NUMBER { $$ = $1; } |
| 135 | | BYE { $$ = $1; *bye = 1; }; |
| 136 | %% |
| 137 | #include <stdio.h> |
| 138 | |
| 139 | /* Urgh. yacc and lex are kind of horrible. This is not thread safe, obviously. */ |
| 140 | static int lexer_read_offset = 0; |
| 141 | static char lexer_input_buffer[1000]; |
| 142 | |
| 143 | int lexer_input(char* buffer, int *bytes_read, int bytes_requested) |
| 144 | { |
| 145 | int bytes_left = strlen(lexer_input_buffer) - lexer_read_offset; |
| 146 | |
| 147 | if (bytes_requested > bytes_left ) |
| 148 | bytes_requested = bytes_left; |
| 149 | memcpy(buffer, &lexer_input_buffer[lexer_read_offset], bytes_requested); |
| 150 | *bytes_read = bytes_requested; |
| 151 | lexer_read_offset += bytes_requested; |
| 152 | return 0; |
| 153 | } |
| 154 | |
| 155 | static void setup_to_parse_string(const char *string) |
| 156 | { |
| 157 | unsigned int len; |
| 158 | |
| 159 | len = strlen(string); |
| 160 | if (len > sizeof(lexer_input_buffer) - 3) |
| 161 | len = sizeof(lexer_input_buffer) - 3; |
| 162 | |
| 163 | strncpy(lexer_input_buffer, string, len); |
| 164 | lexer_input_buffer[len] = '\0'; |
| 165 | lexer_input_buffer[len + 1] = '\0'; /* lex/yacc want string double null terminated! */ |
| 166 | lexer_read_offset = 0; |
| 167 | } |
| 168 | |
| 169 | int evaluate_arithmetic_expression(const char *buffer, long long *ival, double *dval) |
| 170 | { |
| 171 | int rc, bye = 0, has_error = 0; |
| 172 | |
| 173 | setup_to_parse_string(buffer); |
| 174 | rc = yyparse(ival, dval, &has_error, &bye); |
| 175 | yyrestart(NULL); |
| 176 | if (rc || bye || has_error) { |
| 177 | *ival = 0; |
| 178 | *dval = 0; |
| 179 | has_error = 1; |
| 180 | } |
| 181 | return has_error; |
| 182 | } |
| 183 | |
| 184 | int yyerror(__attribute__((unused)) long long *result, |
| 185 | __attribute__((unused)) double *dresult, |
| 186 | __attribute__((unused)) int *has_error, |
| 187 | __attribute__((unused)) int *bye, const char *msg) |
| 188 | { |
| 189 | fprintf(stderr, "%s\n", msg); |
| 190 | return 0; |
| 191 | } |
| 192 | |