3 // ----------------------------------------------------------------------------
4 // data structures for storing the parsed expression in memory
6 typedef struct eval_value {
10 calculated_number number;
11 EVAL_VARIABLE *variable;
12 struct eval_node *expression;
16 typedef struct eval_node {
18 unsigned char operator;
25 // these are used for EVAL_NODE.operator
26 // they are used as internal IDs to identify an operator
27 // THEY ARE NOT USED FOR PARSING OPERATORS LIKE THAT
28 #define EVAL_OPERATOR_NOP '\0'
29 #define EVAL_OPERATOR_EXPRESSION_OPEN '('
30 #define EVAL_OPERATOR_EXPRESSION_CLOSE ')'
31 #define EVAL_OPERATOR_NOT '!'
32 #define EVAL_OPERATOR_PLUS '+'
33 #define EVAL_OPERATOR_MINUS '-'
34 #define EVAL_OPERATOR_AND '&'
35 #define EVAL_OPERATOR_OR '|'
36 #define EVAL_OPERATOR_GREATER_THAN_OR_EQUAL 'G'
37 #define EVAL_OPERATOR_LESS_THAN_OR_EQUAL 'L'
38 #define EVAL_OPERATOR_NOT_EQUAL '~'
39 #define EVAL_OPERATOR_EQUAL '='
40 #define EVAL_OPERATOR_LESS '<'
41 #define EVAL_OPERATOR_GREATER '>'
42 #define EVAL_OPERATOR_MULTIPLY '*'
43 #define EVAL_OPERATOR_DIVIDE '/'
44 #define EVAL_OPERATOR_SIGN_PLUS 'P'
45 #define EVAL_OPERATOR_SIGN_MINUS 'M'
46 #define EVAL_OPERATOR_ABS 'A'
47 #define EVAL_OPERATOR_IF_THEN_ELSE '?'
49 // ----------------------------------------------------------------------------
50 // forward function definitions
52 static inline void eval_node_free(EVAL_NODE *op);
53 static inline EVAL_NODE *parse_full_expression(const char **string, int *error);
54 static inline EVAL_NODE *parse_one_full_operand(const char **string, int *error);
55 static inline calculated_number eval_node(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error);
56 static inline void print_parsed_as_node(BUFFER *out, EVAL_NODE *op, int *error);
57 static inline void print_parsed_as_constant(BUFFER *out, calculated_number n);
59 // ----------------------------------------------------------------------------
60 // evaluation of expressions
62 static inline calculated_number eval_check_number(calculated_number n, int *error) {
63 if(unlikely(isnan(n))) {
64 *error = EVAL_ERROR_VALUE_IS_NAN;
68 if(unlikely(isinf(n))) {
69 *error = EVAL_ERROR_VALUE_IS_INFINITE;
76 static inline calculated_number eval_variable(EVAL_EXPRESSION *exp, EVAL_VARIABLE *v, int *error) {
77 static uint32_t this_hash = 0, now_hash = 0, after_hash = 0, before_hash = 0;
80 if(unlikely(this_hash == 0)) {
81 this_hash = simple_hash("this");
82 now_hash = simple_hash("now");
83 after_hash = simple_hash("after");
84 before_hash = simple_hash("before");
87 if(v->hash == this_hash && !strcmp(v->name, "this")) {
88 n = (exp->this)?*exp->this:NAN;
89 buffer_strcat(exp->error_msg, "[ $this = ");
90 print_parsed_as_constant(exp->error_msg, n);
91 buffer_strcat(exp->error_msg, " ] ");
95 if(v->hash == after_hash && !strcmp(v->name, "after")) {
96 n = (exp->after && *exp->after)?*exp->after:NAN;
97 buffer_strcat(exp->error_msg, "[ $after = ");
98 print_parsed_as_constant(exp->error_msg, n);
99 buffer_strcat(exp->error_msg, " ] ");
103 if(v->hash == before_hash && !strcmp(v->name, "before")) {
104 n = (exp->before && *exp->before)?*exp->before:NAN;
105 buffer_strcat(exp->error_msg, "[ $before = ");
106 print_parsed_as_constant(exp->error_msg, n);
107 buffer_strcat(exp->error_msg, " ] ");
111 if(v->hash == now_hash && !strcmp(v->name, "now")) {
113 buffer_strcat(exp->error_msg, "[ $now = ");
114 print_parsed_as_constant(exp->error_msg, n);
115 buffer_strcat(exp->error_msg, " ] ");
119 if(exp->rrdcalc && health_variable_lookup(v->name, v->hash, exp->rrdcalc, &n)) {
120 buffer_sprintf(exp->error_msg, "[ $%s = ", v->name);
121 print_parsed_as_constant(exp->error_msg, n);
122 buffer_strcat(exp->error_msg, " ] ");
126 *error = EVAL_ERROR_UNKNOWN_VARIABLE;
127 buffer_sprintf(exp->error_msg, "unknown variable '%s'", v->name);
131 static inline calculated_number eval_value(EVAL_EXPRESSION *exp, EVAL_VALUE *v, int *error) {
135 case EVAL_VALUE_EXPRESSION:
136 n = eval_node(exp, v->expression, error);
139 case EVAL_VALUE_NUMBER:
143 case EVAL_VALUE_VARIABLE:
144 n = eval_variable(exp, v->variable, error);
148 *error = EVAL_ERROR_INVALID_VALUE;
153 // return eval_check_number(n, error);
157 static inline int is_true(calculated_number n) {
158 if(isnan(n)) return 0;
159 if(isinf(n)) return 1;
164 calculated_number eval_and(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
165 return is_true(eval_value(exp, &op->ops[0], error)) && is_true(eval_value(exp, &op->ops[1], error));
167 calculated_number eval_or(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
168 return is_true(eval_value(exp, &op->ops[0], error)) || is_true(eval_value(exp, &op->ops[1], error));
170 calculated_number eval_greater_than_or_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
171 calculated_number n1 = eval_value(exp, &op->ops[0], error);
172 calculated_number n2 = eval_value(exp, &op->ops[1], error);
173 return isgreaterequal(n1, n2);
175 calculated_number eval_less_than_or_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
176 calculated_number n1 = eval_value(exp, &op->ops[0], error);
177 calculated_number n2 = eval_value(exp, &op->ops[1], error);
178 return islessequal(n1, n2);
180 calculated_number eval_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
181 calculated_number n1 = eval_value(exp, &op->ops[0], error);
182 calculated_number n2 = eval_value(exp, &op->ops[1], error);
183 if(isnan(n1) && isnan(n2)) return 1;
184 if(isinf(n1) && isinf(n2)) return 1;
185 if(isnan(n1) || isnan(n2)) return 0;
186 if(isinf(n1) || isinf(n2)) return 0;
189 calculated_number eval_not_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
190 return !eval_equal(exp, op, error);
192 calculated_number eval_less(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
193 calculated_number n1 = eval_value(exp, &op->ops[0], error);
194 calculated_number n2 = eval_value(exp, &op->ops[1], error);
195 return isless(n1, n2);
197 calculated_number eval_greater(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
198 calculated_number n1 = eval_value(exp, &op->ops[0], error);
199 calculated_number n2 = eval_value(exp, &op->ops[1], error);
200 return isgreater(n1, n2);
202 calculated_number eval_plus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
203 calculated_number n1 = eval_value(exp, &op->ops[0], error);
204 calculated_number n2 = eval_value(exp, &op->ops[1], error);
205 if(isnan(n1) || isnan(n2)) return NAN;
206 if(isinf(n1) || isinf(n2)) return INFINITY;
209 calculated_number eval_minus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
210 calculated_number n1 = eval_value(exp, &op->ops[0], error);
211 calculated_number n2 = eval_value(exp, &op->ops[1], error);
212 if(isnan(n1) || isnan(n2)) return NAN;
213 if(isinf(n1) || isinf(n2)) return INFINITY;
216 calculated_number eval_multiply(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
217 calculated_number n1 = eval_value(exp, &op->ops[0], error);
218 calculated_number n2 = eval_value(exp, &op->ops[1], error);
219 if(isnan(n1) || isnan(n2)) return NAN;
220 if(isinf(n1) || isinf(n2)) return INFINITY;
223 calculated_number eval_divide(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
224 calculated_number n1 = eval_value(exp, &op->ops[0], error);
225 calculated_number n2 = eval_value(exp, &op->ops[1], error);
226 if(isnan(n1) || isnan(n2)) return NAN;
227 if(isinf(n1) || isinf(n2)) return INFINITY;
230 calculated_number eval_nop(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
231 return eval_value(exp, &op->ops[0], error);
233 calculated_number eval_not(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
234 return !is_true(eval_value(exp, &op->ops[0], error));
236 calculated_number eval_sign_plus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
237 return eval_value(exp, &op->ops[0], error);
239 calculated_number eval_sign_minus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
240 calculated_number n1 = eval_value(exp, &op->ops[0], error);
241 if(isnan(n1)) return NAN;
242 if(isinf(n1)) return INFINITY;
245 calculated_number eval_abs(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
246 calculated_number n1 = eval_value(exp, &op->ops[0], error);
247 if(isnan(n1)) return NAN;
248 if(isinf(n1)) return INFINITY;
251 calculated_number eval_if_then_else(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
252 if(is_true(eval_value(exp, &op->ops[0], error)))
253 return eval_value(exp, &op->ops[1], error);
255 return eval_value(exp, &op->ops[2], error);
258 static struct operator {
259 const char *print_as;
263 calculated_number (*eval)(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error);
265 // this is a random access array
266 // we always access it with a known EVAL_OPERATOR_X
268 [EVAL_OPERATOR_IF_THEN_ELSE] = { "?", 1, 3, 0, eval_if_then_else },
269 [EVAL_OPERATOR_AND] = { "&&", 2, 2, 0, eval_and },
270 [EVAL_OPERATOR_OR] = { "||", 2, 2, 0, eval_or },
271 [EVAL_OPERATOR_GREATER_THAN_OR_EQUAL] = { ">=", 3, 2, 0, eval_greater_than_or_equal },
272 [EVAL_OPERATOR_LESS_THAN_OR_EQUAL] = { "<=", 3, 2, 0, eval_less_than_or_equal },
273 [EVAL_OPERATOR_NOT_EQUAL] = { "!=", 3, 2, 0, eval_not_equal },
274 [EVAL_OPERATOR_EQUAL] = { "==", 3, 2, 0, eval_equal },
275 [EVAL_OPERATOR_LESS] = { "<", 3, 2, 0, eval_less },
276 [EVAL_OPERATOR_GREATER] = { ">", 3, 2, 0, eval_greater },
277 [EVAL_OPERATOR_PLUS] = { "+", 4, 2, 0, eval_plus },
278 [EVAL_OPERATOR_MINUS] = { "-", 4, 2, 0, eval_minus },
279 [EVAL_OPERATOR_MULTIPLY] = { "*", 5, 2, 0, eval_multiply },
280 [EVAL_OPERATOR_DIVIDE] = { "/", 5, 2, 0, eval_divide },
281 [EVAL_OPERATOR_NOT] = { "!", 6, 1, 0, eval_not },
282 [EVAL_OPERATOR_SIGN_PLUS] = { "+", 6, 1, 0, eval_sign_plus },
283 [EVAL_OPERATOR_SIGN_MINUS] = { "-", 6, 1, 0, eval_sign_minus },
284 [EVAL_OPERATOR_ABS] = { "abs(",6,1, 1, eval_abs },
285 [EVAL_OPERATOR_NOP] = { NULL, 7, 1, 0, eval_nop },
286 [EVAL_OPERATOR_EXPRESSION_OPEN] = { NULL, 7, 1, 0, eval_nop },
288 // this should exist in our evaluation list
289 [EVAL_OPERATOR_EXPRESSION_CLOSE] = { NULL, 99, 1, 0, eval_nop }
292 #define eval_precedence(operator) (operators[(unsigned char)(operator)].precedence)
294 static inline calculated_number eval_node(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
295 if(unlikely(op->count != operators[op->operator].parameters)) {
296 *error = EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS;
300 calculated_number n = operators[op->operator].eval(exp, op, error);
302 // return eval_check_number(n, error);
306 // ----------------------------------------------------------------------------
307 // parsed-as generation
309 static inline void print_parsed_as_variable(BUFFER *out, EVAL_VARIABLE *v, int *error) {
311 buffer_sprintf(out, "$%s", v->name);
314 static inline void print_parsed_as_constant(BUFFER *out, calculated_number n) {
315 if(unlikely(isnan(n))) {
316 buffer_strcat(out, "nan");
320 if(unlikely(isinf(n))) {
321 buffer_strcat(out, "inf");
326 snprintfz(b, 100, CALCULATED_NUMBER_FORMAT, n);
328 s = &b[strlen(b) - 1];
329 while(s > b && *s == '0') {
334 if(s > b && *s == '.')
337 buffer_strcat(out, b);
340 static inline void print_parsed_as_value(BUFFER *out, EVAL_VALUE *v, int *error) {
342 case EVAL_VALUE_EXPRESSION:
343 print_parsed_as_node(out, v->expression, error);
346 case EVAL_VALUE_NUMBER:
347 print_parsed_as_constant(out, v->number);
350 case EVAL_VALUE_VARIABLE:
351 print_parsed_as_variable(out, v->variable, error);
355 *error = EVAL_ERROR_INVALID_VALUE;
360 static inline void print_parsed_as_node(BUFFER *out, EVAL_NODE *op, int *error) {
361 if(unlikely(op->count != operators[op->operator].parameters)) {
362 *error = EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS;
366 if(operators[op->operator].parameters == 1) {
368 if(operators[op->operator].print_as)
369 buffer_sprintf(out, "%s", operators[op->operator].print_as);
371 //if(op->operator == EVAL_OPERATOR_EXPRESSION_OPEN)
372 // buffer_strcat(out, "(");
374 print_parsed_as_value(out, &op->ops[0], error);
376 //if(op->operator == EVAL_OPERATOR_EXPRESSION_OPEN)
377 // buffer_strcat(out, ")");
380 else if(operators[op->operator].parameters == 2) {
381 buffer_strcat(out, "(");
382 print_parsed_as_value(out, &op->ops[0], error);
384 if(operators[op->operator].print_as)
385 buffer_sprintf(out, " %s ", operators[op->operator].print_as);
387 print_parsed_as_value(out, &op->ops[1], error);
388 buffer_strcat(out, ")");
390 else if(op->operator == EVAL_OPERATOR_IF_THEN_ELSE && operators[op->operator].parameters == 3) {
391 buffer_strcat(out, "(");
392 print_parsed_as_value(out, &op->ops[0], error);
394 if(operators[op->operator].print_as)
395 buffer_sprintf(out, " %s ", operators[op->operator].print_as);
397 print_parsed_as_value(out, &op->ops[1], error);
398 buffer_strcat(out, " : ");
399 print_parsed_as_value(out, &op->ops[2], error);
400 buffer_strcat(out, ")");
403 if(operators[op->operator].isfunction)
404 buffer_strcat(out, ")");
407 // ----------------------------------------------------------------------------
408 // parsing expressions
411 static inline void skip_spaces(const char **string) {
412 const char *s = *string;
413 while(isspace(*s)) s++;
417 // what character can appear just after an operator keyword
419 static inline int isoperatorterm_word(const char s) {
420 if(isspace(s) || s == '(' || s == '$' || s == '!' || s == '-' || s == '+' || isdigit(s) || !s)
426 // what character can appear just after an operator symbol?
427 static inline int isoperatorterm_symbol(const char s) {
428 if(isoperatorterm_word(s) || isalpha(s))
434 // return 1 if the character should never appear in a variable
435 static inline int isvariableterm(const char s) {
436 if(isalnum(s) || s == '.' || s == '_')
442 // ----------------------------------------------------------------------------
445 static inline int parse_and(const char **string) {
446 const char *s = *string;
449 if((s[0] == 'A' || s[0] == 'a') && (s[1] == 'N' || s[1] == 'n') && (s[2] == 'D' || s[2] == 'd') && isoperatorterm_word(s[3])) {
455 if(s[0] == '&' && s[1] == '&' && isoperatorterm_symbol(s[2])) {
463 static inline int parse_or(const char **string) {
464 const char *s = *string;
467 if((s[0] == 'O' || s[0] == 'o') && (s[1] == 'R' || s[1] == 'r') && isoperatorterm_word(s[2])) {
473 if(s[0] == '|' && s[1] == '|' && isoperatorterm_symbol(s[2])) {
481 static inline int parse_greater_than_or_equal(const char **string) {
482 const char *s = *string;
485 if(s[0] == '>' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
493 static inline int parse_less_than_or_equal(const char **string) {
494 const char *s = *string;
497 if (s[0] == '<' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
505 static inline int parse_greater(const char **string) {
506 const char *s = *string;
509 if(s[0] == '>' && isoperatorterm_symbol(s[1])) {
517 static inline int parse_less(const char **string) {
518 const char *s = *string;
521 if(s[0] == '<' && isoperatorterm_symbol(s[1])) {
529 static inline int parse_equal(const char **string) {
530 const char *s = *string;
533 if(s[0] == '=' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
539 if(s[0] == '=' && isoperatorterm_symbol(s[1])) {
547 static inline int parse_not_equal(const char **string) {
548 const char *s = *string;
551 if(s[0] == '!' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
557 if(s[0] == '<' && s[1] == '>' && isoperatorterm_symbol(s[2])) {
564 static inline int parse_not(const char **string) {
565 const char *s = *string;
568 if((s[0] == 'N' || s[0] == 'n') && (s[1] == 'O' || s[1] == 'o') && (s[2] == 'T' || s[2] == 't') && isoperatorterm_word(s[3])) {
581 static inline int parse_multiply(const char **string) {
582 const char *s = *string;
585 if(s[0] == '*' && isoperatorterm_symbol(s[1])) {
593 static inline int parse_divide(const char **string) {
594 const char *s = *string;
597 if(s[0] == '/' && isoperatorterm_symbol(s[1])) {
605 static inline int parse_minus(const char **string) {
606 const char *s = *string;
609 if(s[0] == '-' && isoperatorterm_symbol(s[1])) {
617 static inline int parse_plus(const char **string) {
618 const char *s = *string;
621 if(s[0] == '+' && isoperatorterm_symbol(s[1])) {
629 static inline int parse_open_subexpression(const char **string) {
630 const char *s = *string;
641 #define parse_close_function(x) parse_close_subexpression(x)
643 static inline int parse_close_subexpression(const char **string) {
644 const char *s = *string;
655 static inline int parse_variable(const char **string, char *buffer, size_t len) {
656 const char *s = *string;
663 while(*s && !isvariableterm(*s) && i < len)
677 static inline int parse_constant(const char **string, calculated_number *number) {
679 calculated_number n = strtold(*string, &end);
680 if(unlikely(!end || *string == end)) {
689 static inline int parse_abs(const char **string) {
690 const char *s = *string;
693 if((s[0] == 'A' || s[0] == 'a') && (s[1] == 'B' || s[1] == 'b') && (s[2] == 'S' || s[2] == 's') && s[3] == '(') {
701 static inline int parse_if_then_else(const char **string) {
702 const char *s = *string;
713 static struct operator_parser {
715 int (*parse)(const char **);
716 } operator_parsers[] = {
717 // the order in this list is important!
718 // the first matching will be used
719 // so place the longer of overlapping ones
722 { EVAL_OPERATOR_AND, parse_and },
723 { EVAL_OPERATOR_OR, parse_or },
724 { EVAL_OPERATOR_GREATER_THAN_OR_EQUAL, parse_greater_than_or_equal },
725 { EVAL_OPERATOR_LESS_THAN_OR_EQUAL, parse_less_than_or_equal },
726 { EVAL_OPERATOR_NOT_EQUAL, parse_not_equal },
727 { EVAL_OPERATOR_EQUAL, parse_equal },
728 { EVAL_OPERATOR_LESS, parse_less },
729 { EVAL_OPERATOR_GREATER, parse_greater },
730 { EVAL_OPERATOR_PLUS, parse_plus },
731 { EVAL_OPERATOR_MINUS, parse_minus },
732 { EVAL_OPERATOR_MULTIPLY, parse_multiply },
733 { EVAL_OPERATOR_DIVIDE, parse_divide },
734 { EVAL_OPERATOR_IF_THEN_ELSE, parse_if_then_else },
736 /* we should not put in this list the following:
742 * these are handled in code
746 { EVAL_OPERATOR_NOP, NULL }
749 static inline unsigned char parse_operator(const char **string, int *precedence) {
753 for(i = 0 ; operator_parsers[i].parse != NULL ; i++)
754 if(operator_parsers[i].parse(string)) {
755 if(precedence) *precedence = eval_precedence(operator_parsers[i].id);
756 return operator_parsers[i].id;
759 return EVAL_OPERATOR_NOP;
762 // ----------------------------------------------------------------------------
765 static inline EVAL_NODE *eval_node_alloc(int count) {
768 EVAL_NODE *op = callocz(1, sizeof(EVAL_NODE) + (sizeof(EVAL_VALUE) * count));
771 op->operator = EVAL_OPERATOR_NOP;
772 op->precedence = eval_precedence(EVAL_OPERATOR_NOP);
777 static inline void eval_node_set_value_to_node(EVAL_NODE *op, int pos, EVAL_NODE *value) {
779 fatal("Invalid request to set position %d of OPERAND that has only %d values", pos + 1, op->count + 1);
781 op->ops[pos].type = EVAL_VALUE_EXPRESSION;
782 op->ops[pos].expression = value;
785 static inline void eval_node_set_value_to_constant(EVAL_NODE *op, int pos, calculated_number value) {
787 fatal("Invalid request to set position %d of OPERAND that has only %d values", pos + 1, op->count + 1);
789 op->ops[pos].type = EVAL_VALUE_NUMBER;
790 op->ops[pos].number = value;
793 static inline void eval_node_set_value_to_variable(EVAL_NODE *op, int pos, const char *variable) {
795 fatal("Invalid request to set position %d of OPERAND that has only %d values", pos + 1, op->count + 1);
797 op->ops[pos].type = EVAL_VALUE_VARIABLE;
798 op->ops[pos].variable = callocz(1, sizeof(EVAL_VARIABLE));
799 op->ops[pos].variable->name = strdupz(variable);
800 op->ops[pos].variable->hash = simple_hash(op->ops[pos].variable->name);
803 static inline void eval_variable_free(EVAL_VARIABLE *v) {
808 static inline void eval_value_free(EVAL_VALUE *v) {
810 case EVAL_VALUE_EXPRESSION:
811 eval_node_free(v->expression);
814 case EVAL_VALUE_VARIABLE:
815 eval_variable_free(v->variable);
823 static inline void eval_node_free(EVAL_NODE *op) {
826 for(i = op->count - 1; i >= 0 ;i--)
827 eval_value_free(&op->ops[i]);
833 // ----------------------------------------------------------------------------
836 // helper function to avoid allocations all over the place
837 static inline EVAL_NODE *parse_next_operand_given_its_operator(const char **string, unsigned char operator_type, int *error) {
838 EVAL_NODE *sub = parse_one_full_operand(string, error);
839 if(!sub) return NULL;
841 EVAL_NODE *op = eval_node_alloc(1);
842 op->operator = operator_type;
843 eval_node_set_value_to_node(op, 0, sub);
847 // parse a full operand, including its sign or other associative operator (e.g. NOT)
848 static inline EVAL_NODE *parse_one_full_operand(const char **string, int *error) {
849 char variable_buffer[EVAL_MAX_VARIABLE_NAME_LENGTH + 1];
850 EVAL_NODE *op1 = NULL;
851 calculated_number number;
853 *error = EVAL_ERROR_OK;
857 *error = EVAL_ERROR_MISSING_OPERAND;
861 if(parse_not(string)) {
862 op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_NOT, error);
863 op1->precedence = eval_precedence(EVAL_OPERATOR_NOT);
865 else if(parse_plus(string)) {
866 op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_SIGN_PLUS, error);
867 op1->precedence = eval_precedence(EVAL_OPERATOR_SIGN_PLUS);
869 else if(parse_minus(string)) {
870 op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_SIGN_MINUS, error);
871 op1->precedence = eval_precedence(EVAL_OPERATOR_SIGN_MINUS);
873 else if(parse_abs(string)) {
874 op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_ABS, error);
875 op1->precedence = eval_precedence(EVAL_OPERATOR_ABS);
877 else if(parse_open_subexpression(string)) {
878 EVAL_NODE *sub = parse_full_expression(string, error);
880 op1 = eval_node_alloc(1);
881 op1->operator = EVAL_OPERATOR_EXPRESSION_OPEN;
882 op1->precedence = eval_precedence(EVAL_OPERATOR_EXPRESSION_OPEN);
883 eval_node_set_value_to_node(op1, 0, sub);
884 if(!parse_close_subexpression(string)) {
885 *error = EVAL_ERROR_MISSING_CLOSE_SUBEXPRESSION;
891 else if(parse_variable(string, variable_buffer, EVAL_MAX_VARIABLE_NAME_LENGTH)) {
892 op1 = eval_node_alloc(1);
893 op1->operator = EVAL_OPERATOR_NOP;
894 eval_node_set_value_to_variable(op1, 0, variable_buffer);
896 else if(parse_constant(string, &number)) {
897 op1 = eval_node_alloc(1);
898 op1->operator = EVAL_OPERATOR_NOP;
899 eval_node_set_value_to_constant(op1, 0, number);
902 *error = EVAL_ERROR_UNKNOWN_OPERAND;
904 *error = EVAL_ERROR_MISSING_OPERAND;
909 // parse an operator and the rest of the expression
910 // precedence processing is handled here
911 static inline EVAL_NODE *parse_rest_of_expression(const char **string, int *error, EVAL_NODE *op1) {
912 EVAL_NODE *op2 = NULL;
913 unsigned char operator;
916 operator = parse_operator(string, &precedence);
919 if(operator != EVAL_OPERATOR_NOP) {
920 op2 = parse_one_full_operand(string, error);
922 // error is already reported
927 EVAL_NODE *op = eval_node_alloc(operators[operator].parameters);
928 op->operator = operator;
929 op->precedence = precedence;
931 if(operator == EVAL_OPERATOR_IF_THEN_ELSE && op->count == 3) {
934 if(**string != ':') {
938 *error = EVAL_ERROR_IF_THEN_ELSE_MISSING_ELSE;
945 EVAL_NODE *op3 = parse_one_full_operand(string, error);
950 // error is already reported
954 eval_node_set_value_to_node(op, 2, op3);
957 eval_node_set_value_to_node(op, 1, op2);
959 // precedence processing
960 // if this operator has a higher precedence compared to its next
961 // put the next operator on top of us (top = evaluated later)
962 // function recursion does the rest...
963 if(op->precedence > op1->precedence && op1->count == 2 && op1->operator != '(' && op1->ops[1].type == EVAL_VALUE_EXPRESSION) {
964 eval_node_set_value_to_node(op, 0, op1->ops[1].expression);
965 op1->ops[1].expression = op;
969 eval_node_set_value_to_node(op, 0, op1);
971 return parse_rest_of_expression(string, error, op);
973 else if(**string == ')') {
979 *error = EVAL_ERROR_MISSING_OPERATOR;
985 // high level function to parse an expression or a sub-expression
986 static inline EVAL_NODE *parse_full_expression(const char **string, int *error) {
987 EVAL_NODE *op1 = NULL;
989 op1 = parse_one_full_operand(string, error);
991 *error = EVAL_ERROR_MISSING_OPERAND;
995 return parse_rest_of_expression(string, error, op1);
998 // ----------------------------------------------------------------------------
1001 int expression_evaluate(EVAL_EXPRESSION *exp) {
1002 exp->error = EVAL_ERROR_OK;
1004 buffer_reset(exp->error_msg);
1005 exp->result = eval_node(exp, (EVAL_NODE *)exp->nodes, &exp->error);
1007 if(exp->error == EVAL_ERROR_OK)
1008 exp->result = eval_check_number(exp->result, &exp->error);
1010 if(exp->error != EVAL_ERROR_OK) {
1013 if(buffer_strlen(exp->error_msg))
1014 buffer_strcat(exp->error_msg, "; ");
1016 buffer_sprintf(exp->error_msg, "failed to evaluate expression with error %d (%s)", exp->error, expression_strerror(exp->error));
1023 EVAL_EXPRESSION *expression_parse(const char *string, const char **failed_at, int *error) {
1024 const char *s = string;
1025 int err = EVAL_ERROR_OK;
1026 unsigned long pos = 0;
1028 EVAL_NODE *op = parse_full_expression(&s, &err);
1035 err = EVAL_ERROR_REMAINING_GARBAGE;
1038 if (failed_at) *failed_at = s;
1039 if (error) *error = err;
1042 pos = s - string + 1;
1043 error("failed to parse expression '%s': %s at character %lu (i.e.: '%s').", string, expression_strerror(err), pos, s);
1047 BUFFER *out = buffer_create(1024);
1048 print_parsed_as_node(out, op, &err);
1049 if(err != EVAL_ERROR_OK) {
1050 error("failed to re-generate expression '%s' with reason: %s", string, expression_strerror(err));
1056 EVAL_EXPRESSION *exp = callocz(1, sizeof(EVAL_EXPRESSION));
1058 exp->source = strdupz(string);
1059 exp->parsed_as = strdupz(buffer_tostring(out));
1062 exp->error_msg = buffer_create(100);
1063 exp->nodes = (void *)op;
1068 void expression_free(EVAL_EXPRESSION *exp) {
1071 if(exp->nodes) eval_node_free((EVAL_NODE *)exp->nodes);
1072 freez((void *)exp->source);
1073 freez((void *)exp->parsed_as);
1074 buffer_free(exp->error_msg);
1078 const char *expression_strerror(int error) {
1083 case EVAL_ERROR_MISSING_CLOSE_SUBEXPRESSION:
1084 return "missing closing parenthesis";
1086 case EVAL_ERROR_UNKNOWN_OPERAND:
1087 return "unknown operand";
1089 case EVAL_ERROR_MISSING_OPERAND:
1090 return "expected operand";
1092 case EVAL_ERROR_MISSING_OPERATOR:
1093 return "expected operator";
1095 case EVAL_ERROR_REMAINING_GARBAGE:
1096 return "remaining characters after expression";
1098 case EVAL_ERROR_INVALID_VALUE:
1099 return "invalid value structure - internal error";
1101 case EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS:
1102 return "wrong number of operands for operation - internal error";
1104 case EVAL_ERROR_VALUE_IS_NAN:
1105 return "value is unset";
1107 case EVAL_ERROR_VALUE_IS_INFINITE:
1108 return "computed value is infinite";
1110 case EVAL_ERROR_UNKNOWN_VARIABLE:
1111 return "undefined variable";
1113 case EVAL_ERROR_IF_THEN_ELSE_MISSING_ELSE:
1114 return "missing second sub-expression of inline conditional";
1117 return "unknown error";