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'
48 // ----------------------------------------------------------------------------
49 // forward function definitions
51 static inline void eval_node_free(EVAL_NODE *op);
52 static inline EVAL_NODE *parse_full_expression(const char **string, int *error);
53 static inline EVAL_NODE *parse_one_full_operand(const char **string, int *error);
54 static inline calculated_number eval_node(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error);
55 static inline void print_parsed_as_node(BUFFER *out, EVAL_NODE *op, int *error);
56 static inline void print_parsed_as_constant(BUFFER *out, calculated_number n);
58 // ----------------------------------------------------------------------------
59 // evaluation of expressions
61 static inline calculated_number eval_check_number(calculated_number n, int *error) {
62 if(unlikely(isnan(n))) {
63 *error = EVAL_ERROR_VALUE_IS_NAN;
67 if(unlikely(isinf(n))) {
68 *error = EVAL_ERROR_VALUE_IS_INFINITE;
75 static inline calculated_number eval_variable(EVAL_EXPRESSION *exp, EVAL_VARIABLE *v, int *error) {
76 static uint32_t this_hash = 0;
78 if(unlikely(this_hash == 0))
79 this_hash = simple_hash("this");
81 if(exp->this && v->hash == this_hash && !strcmp(v->name, "this")) {
82 buffer_strcat(exp->error_msg, "[ $this = ");
83 print_parsed_as_constant(exp->error_msg, *exp->this);
84 buffer_strcat(exp->error_msg, " ] ");
89 if(exp->rrdcalc && health_variable_lookup(v->name, v->hash, exp->rrdcalc, &n)) {
90 buffer_sprintf(exp->error_msg, "[ $%s = ", v->name);
91 print_parsed_as_constant(exp->error_msg, n);
92 buffer_strcat(exp->error_msg, " ] ");
96 *error = EVAL_ERROR_UNKNOWN_VARIABLE;
97 buffer_sprintf(exp->error_msg, "unknown variable '%s'", v->name);
101 static inline calculated_number eval_value(EVAL_EXPRESSION *exp, EVAL_VALUE *v, int *error) {
105 case EVAL_VALUE_EXPRESSION:
106 n = eval_node(exp, v->expression, error);
109 case EVAL_VALUE_NUMBER:
113 case EVAL_VALUE_VARIABLE:
114 n = eval_variable(exp, v->variable, error);
118 *error = EVAL_ERROR_INVALID_VALUE;
123 // return eval_check_number(n, error);
127 calculated_number eval_and(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
128 return eval_value(exp, &op->ops[0], error) && eval_value(exp, &op->ops[1], error);
130 calculated_number eval_or(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
131 return eval_value(exp, &op->ops[0], error) || eval_value(exp, &op->ops[1], error);
133 calculated_number eval_greater_than_or_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
134 return eval_value(exp, &op->ops[0], error) >= eval_value(exp, &op->ops[1], error);
136 calculated_number eval_less_than_or_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
137 return eval_value(exp, &op->ops[0], error) <= eval_value(exp, &op->ops[1], error);
139 calculated_number eval_not_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
140 return eval_value(exp, &op->ops[0], error) != eval_value(exp, &op->ops[1], error);
142 calculated_number eval_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
143 return eval_value(exp, &op->ops[0], error) == eval_value(exp, &op->ops[1], error);
145 calculated_number eval_less(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
146 return eval_value(exp, &op->ops[0], error) < eval_value(exp, &op->ops[1], error);
148 calculated_number eval_greater(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
149 return eval_value(exp, &op->ops[0], error) > eval_value(exp, &op->ops[1], error);
151 calculated_number eval_plus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
152 return eval_value(exp, &op->ops[0], error) + eval_value(exp, &op->ops[1], error);
154 calculated_number eval_minus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
155 return eval_value(exp, &op->ops[0], error) - eval_value(exp, &op->ops[1], error);
157 calculated_number eval_multiply(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
158 return eval_value(exp, &op->ops[0], error) * eval_value(exp, &op->ops[1], error);
160 calculated_number eval_divide(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
161 return eval_value(exp, &op->ops[0], error) / eval_value(exp, &op->ops[1], error);
163 calculated_number eval_nop(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
164 return eval_value(exp, &op->ops[0], error);
166 calculated_number eval_not(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
167 return !eval_value(exp, &op->ops[0], error);
169 calculated_number eval_sign_plus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
170 return eval_value(exp, &op->ops[0], error);
172 calculated_number eval_sign_minus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
173 return -eval_value(exp, &op->ops[0], error);
175 calculated_number eval_abs(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
176 calculated_number n = eval_value(exp, &op->ops[0], error);
180 static struct operator {
181 const char *print_as;
185 calculated_number (*eval)(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error);
187 // this is a random access array
188 // we always access it with a known EVAL_OPERATOR_X
190 [EVAL_OPERATOR_AND] = { "&&", 2, 2, 0, eval_and },
191 [EVAL_OPERATOR_OR] = { "||", 2, 2, 0, eval_or },
192 [EVAL_OPERATOR_GREATER_THAN_OR_EQUAL] = { ">=", 3, 2, 0, eval_greater_than_or_equal },
193 [EVAL_OPERATOR_LESS_THAN_OR_EQUAL] = { "<=", 3, 2, 0, eval_less_than_or_equal },
194 [EVAL_OPERATOR_NOT_EQUAL] = { "!=", 3, 2, 0, eval_not_equal },
195 [EVAL_OPERATOR_EQUAL] = { "==", 3, 2, 0, eval_equal },
196 [EVAL_OPERATOR_LESS] = { "<", 3, 2, 0, eval_less },
197 [EVAL_OPERATOR_GREATER] = { ">", 3, 2, 0, eval_greater },
198 [EVAL_OPERATOR_PLUS] = { "+", 4, 2, 0, eval_plus },
199 [EVAL_OPERATOR_MINUS] = { "-", 4, 2, 0, eval_minus },
200 [EVAL_OPERATOR_MULTIPLY] = { "*", 5, 2, 0, eval_multiply },
201 [EVAL_OPERATOR_DIVIDE] = { "/", 5, 2, 0, eval_divide },
202 [EVAL_OPERATOR_NOT] = { "!", 6, 1, 0, eval_not },
203 [EVAL_OPERATOR_SIGN_PLUS] = { "+", 6, 1, 0, eval_sign_plus },
204 [EVAL_OPERATOR_SIGN_MINUS] = { "-", 6, 1, 0, eval_sign_minus },
205 [EVAL_OPERATOR_ABS] = { "abs(",6,1, 1, eval_abs },
206 [EVAL_OPERATOR_NOP] = { NULL, 7, 1, 0, eval_nop },
207 [EVAL_OPERATOR_EXPRESSION_OPEN] = { NULL, 7, 1, 0, eval_nop },
209 // this should exist in our evaluation list
210 [EVAL_OPERATOR_EXPRESSION_CLOSE] = { NULL, 7, 1, 0, eval_nop }
213 #define eval_precedence(operator) (operators[(unsigned char)(operator)].precedence)
215 static inline calculated_number eval_node(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
216 if(unlikely(op->count != operators[op->operator].parameters)) {
217 *error = EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS;
221 calculated_number n = operators[op->operator].eval(exp, op, error);
223 // return eval_check_number(n, error);
227 // ----------------------------------------------------------------------------
228 // parsed-as generation
230 static inline void print_parsed_as_variable(BUFFER *out, EVAL_VARIABLE *v, int *error) {
232 buffer_sprintf(out, "$%s", v->name);
235 static inline void print_parsed_as_constant(BUFFER *out, calculated_number n) {
236 if(unlikely(isnan(n))) {
237 buffer_strcat(out, "nan");
241 if(unlikely(isinf(n))) {
242 buffer_strcat(out, "inf");
247 snprintfz(b, 100, CALCULATED_NUMBER_FORMAT, n);
249 s = &b[strlen(b) - 1];
250 while(s > b && *s == '0') {
255 if(s > b && *s == '.')
258 buffer_strcat(out, b);
261 static inline void print_parsed_as_value(BUFFER *out, EVAL_VALUE *v, int *error) {
263 case EVAL_VALUE_EXPRESSION:
264 print_parsed_as_node(out, v->expression, error);
267 case EVAL_VALUE_NUMBER:
268 print_parsed_as_constant(out, v->number);
271 case EVAL_VALUE_VARIABLE:
272 print_parsed_as_variable(out, v->variable, error);
276 *error = EVAL_ERROR_INVALID_VALUE;
281 static inline void print_parsed_as_node(BUFFER *out, EVAL_NODE *op, int *error) {
282 if(unlikely(op->count != operators[op->operator].parameters)) {
283 *error = EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS;
287 if(operators[op->operator].parameters == 1) {
289 if(operators[op->operator].print_as)
290 buffer_sprintf(out, "%s", operators[op->operator].print_as);
292 //if(op->operator == EVAL_OPERATOR_EXPRESSION_OPEN)
293 // buffer_strcat(out, "(");
295 print_parsed_as_value(out, &op->ops[0], error);
297 //if(op->operator == EVAL_OPERATOR_EXPRESSION_OPEN)
298 // buffer_strcat(out, ")");
301 else if(operators[op->operator].parameters == 2) {
302 buffer_strcat(out, "(");
303 print_parsed_as_value(out, &op->ops[0], error);
305 if(operators[op->operator].print_as)
306 buffer_sprintf(out, " %s ", operators[op->operator].print_as);
308 print_parsed_as_value(out, &op->ops[1], error);
309 buffer_strcat(out, ")");
312 if(operators[op->operator].isfunction)
313 buffer_strcat(out, ")");
316 // ----------------------------------------------------------------------------
317 // parsing expressions
320 static inline void skip_spaces(const char **string) {
321 const char *s = *string;
322 while(isspace(*s)) s++;
326 // what character can appear just after an operator keyword
328 static inline int isoperatorterm_word(const char s) {
329 if(isspace(s) || s == '(' || s == '$' || s == '!' || s == '-' || s == '+' || isdigit(s) || !s)
335 // what character can appear just after an operator symbol?
336 static inline int isoperatorterm_symbol(const char s) {
337 if(isoperatorterm_word(s) || isalpha(s))
343 // return 1 if the character should never appear in a variable
344 static inline int isvariableterm(const char s) {
345 if(isalnum(s) || s == '.' || s == '_')
351 // ----------------------------------------------------------------------------
354 static inline int parse_and(const char **string) {
355 const char *s = *string;
358 if((s[0] == 'A' || s[0] == 'a') && (s[1] == 'N' || s[1] == 'n') && (s[2] == 'D' || s[2] == 'd') && isoperatorterm_word(s[3])) {
364 if(s[0] == '&' && s[1] == '&' && isoperatorterm_symbol(s[2])) {
372 static inline int parse_or(const char **string) {
373 const char *s = *string;
376 if((s[0] == 'O' || s[0] == 'o') && (s[1] == 'R' || s[1] == 'r') && isoperatorterm_word(s[2])) {
382 if(s[0] == '|' && s[1] == '|' && isoperatorterm_symbol(s[2])) {
390 static inline int parse_greater_than_or_equal(const char **string) {
391 const char *s = *string;
394 if(s[0] == '>' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
402 static inline int parse_less_than_or_equal(const char **string) {
403 const char *s = *string;
406 if (s[0] == '<' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
414 static inline int parse_greater(const char **string) {
415 const char *s = *string;
418 if(s[0] == '>' && isoperatorterm_symbol(s[1])) {
426 static inline int parse_less(const char **string) {
427 const char *s = *string;
430 if(s[0] == '<' && isoperatorterm_symbol(s[1])) {
438 static inline int parse_equal(const char **string) {
439 const char *s = *string;
442 if(s[0] == '=' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
448 if(s[0] == '=' && isoperatorterm_symbol(s[1])) {
456 static inline int parse_not_equal(const char **string) {
457 const char *s = *string;
460 if(s[0] == '!' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
466 if(s[0] == '<' && s[1] == '>' && isoperatorterm_symbol(s[2])) {
473 static inline int parse_not(const char **string) {
474 const char *s = *string;
477 if((s[0] == 'N' || s[0] == 'n') && (s[1] == 'O' || s[1] == 'o') && (s[2] == 'T' || s[2] == 't') && isoperatorterm_word(s[3])) {
490 static inline int parse_multiply(const char **string) {
491 const char *s = *string;
494 if(s[0] == '*' && isoperatorterm_symbol(s[1])) {
502 static inline int parse_divide(const char **string) {
503 const char *s = *string;
506 if(s[0] == '/' && isoperatorterm_symbol(s[1])) {
514 static inline int parse_minus(const char **string) {
515 const char *s = *string;
518 if(s[0] == '-' && isoperatorterm_symbol(s[1])) {
526 static inline int parse_plus(const char **string) {
527 const char *s = *string;
530 if(s[0] == '+' && isoperatorterm_symbol(s[1])) {
538 static inline int parse_open_subexpression(const char **string) {
539 const char *s = *string;
550 #define parse_close_function(x) parse_close_subexpression(x)
552 static inline int parse_close_subexpression(const char **string) {
553 const char *s = *string;
564 static inline int parse_variable(const char **string, char *buffer, size_t len) {
565 const char *s = *string;
572 while(*s && !isvariableterm(*s) && i < len)
586 static inline int parse_constant(const char **string, calculated_number *number) {
588 calculated_number n = strtold(*string, &end);
589 if(unlikely(!end || *string == end)) {
598 static inline int parse_abs(const char **string) {
599 const char *s = *string;
602 if((s[0] == 'A' || s[0] == 'a') && (s[1] == 'B' || s[1] == 'b') && (s[2] == 'S' || s[2] == 's') && s[3] == '(') {
610 static struct operator_parser {
612 int (*parse)(const char **);
613 } operator_parsers[] = {
614 // the order in this list is important!
615 // the first matching will be used
616 // so place the longer of overlapping ones
619 { EVAL_OPERATOR_AND, parse_and },
620 { EVAL_OPERATOR_OR, parse_or },
621 { EVAL_OPERATOR_GREATER_THAN_OR_EQUAL, parse_greater_than_or_equal },
622 { EVAL_OPERATOR_LESS_THAN_OR_EQUAL, parse_less_than_or_equal },
623 { EVAL_OPERATOR_NOT_EQUAL, parse_not_equal },
624 { EVAL_OPERATOR_EQUAL, parse_equal },
625 { EVAL_OPERATOR_LESS, parse_less },
626 { EVAL_OPERATOR_GREATER, parse_greater },
627 { EVAL_OPERATOR_PLUS, parse_plus },
628 { EVAL_OPERATOR_MINUS, parse_minus },
629 { EVAL_OPERATOR_MULTIPLY, parse_multiply },
630 { EVAL_OPERATOR_DIVIDE, parse_divide },
632 /* we should not put in this list the following:
638 * these are handled in code
642 { EVAL_OPERATOR_NOP, NULL }
645 static inline unsigned char parse_operator(const char **string, int *precedence) {
649 for(i = 0 ; operator_parsers[i].parse != NULL ; i++)
650 if(operator_parsers[i].parse(string)) {
651 if(precedence) *precedence = eval_precedence(operator_parsers[i].id);
652 return operator_parsers[i].id;
655 return EVAL_OPERATOR_NOP;
658 // ----------------------------------------------------------------------------
661 static inline EVAL_NODE *eval_node_alloc(int count) {
664 EVAL_NODE *op = callocz(1, sizeof(EVAL_NODE) + (sizeof(EVAL_VALUE) * count));
667 op->operator = EVAL_OPERATOR_NOP;
668 op->precedence = eval_precedence(EVAL_OPERATOR_NOP);
673 static inline void eval_node_set_value_to_node(EVAL_NODE *op, int pos, EVAL_NODE *value) {
675 fatal("Invalid request to set position %d of OPERAND that has only %d values", pos + 1, op->count + 1);
677 op->ops[pos].type = EVAL_VALUE_EXPRESSION;
678 op->ops[pos].expression = value;
681 static inline void eval_node_set_value_to_constant(EVAL_NODE *op, int pos, calculated_number value) {
683 fatal("Invalid request to set position %d of OPERAND that has only %d values", pos + 1, op->count + 1);
685 op->ops[pos].type = EVAL_VALUE_NUMBER;
686 op->ops[pos].number = value;
689 static inline void eval_node_set_value_to_variable(EVAL_NODE *op, int pos, const char *variable) {
691 fatal("Invalid request to set position %d of OPERAND that has only %d values", pos + 1, op->count + 1);
693 op->ops[pos].type = EVAL_VALUE_VARIABLE;
694 op->ops[pos].variable = callocz(1, sizeof(EVAL_VARIABLE));
695 op->ops[pos].variable->name = strdupz(variable);
696 op->ops[pos].variable->hash = simple_hash(op->ops[pos].variable->name);
699 static inline void eval_variable_free(EVAL_VARIABLE *v) {
704 static inline void eval_value_free(EVAL_VALUE *v) {
706 case EVAL_VALUE_EXPRESSION:
707 eval_node_free(v->expression);
710 case EVAL_VALUE_VARIABLE:
711 eval_variable_free(v->variable);
719 static inline void eval_node_free(EVAL_NODE *op) {
722 for(i = op->count - 1; i >= 0 ;i--)
723 eval_value_free(&op->ops[i]);
729 // ----------------------------------------------------------------------------
732 // helper function to avoid allocations all over the place
733 static inline EVAL_NODE *parse_next_operand_given_its_operator(const char **string, unsigned char operator_type, int *error) {
734 EVAL_NODE *sub = parse_one_full_operand(string, error);
735 if(!sub) return NULL;
737 EVAL_NODE *op = eval_node_alloc(1);
738 op->operator = operator_type;
739 eval_node_set_value_to_node(op, 0, sub);
743 // parse a full operand, including its sign or other associative operator (e.g. NOT)
744 static inline EVAL_NODE *parse_one_full_operand(const char **string, int *error) {
745 char variable_buffer[EVAL_MAX_VARIABLE_NAME_LENGTH + 1];
746 EVAL_NODE *op1 = NULL;
747 calculated_number number;
749 *error = EVAL_ERROR_OK;
753 *error = EVAL_ERROR_MISSING_OPERAND;
757 if(parse_not(string)) {
758 op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_NOT, error);
759 op1->precedence = eval_precedence(EVAL_OPERATOR_NOT);
761 else if(parse_plus(string)) {
762 op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_SIGN_PLUS, error);
763 op1->precedence = eval_precedence(EVAL_OPERATOR_SIGN_PLUS);
765 else if(parse_minus(string)) {
766 op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_SIGN_MINUS, error);
767 op1->precedence = eval_precedence(EVAL_OPERATOR_SIGN_MINUS);
769 else if(parse_abs(string)) {
770 op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_ABS, error);
771 op1->precedence = eval_precedence(EVAL_OPERATOR_ABS);
773 else if(parse_open_subexpression(string)) {
774 EVAL_NODE *sub = parse_full_expression(string, error);
776 op1 = eval_node_alloc(1);
777 op1->operator = EVAL_OPERATOR_EXPRESSION_OPEN;
778 op1->precedence = eval_precedence(EVAL_OPERATOR_EXPRESSION_OPEN);
779 eval_node_set_value_to_node(op1, 0, sub);
780 if(!parse_close_subexpression(string)) {
781 *error = EVAL_ERROR_MISSING_CLOSE_SUBEXPRESSION;
787 else if(parse_variable(string, variable_buffer, EVAL_MAX_VARIABLE_NAME_LENGTH)) {
788 op1 = eval_node_alloc(1);
789 op1->operator = EVAL_OPERATOR_NOP;
790 eval_node_set_value_to_variable(op1, 0, variable_buffer);
792 else if(parse_constant(string, &number)) {
793 op1 = eval_node_alloc(1);
794 op1->operator = EVAL_OPERATOR_NOP;
795 eval_node_set_value_to_constant(op1, 0, number);
798 *error = EVAL_ERROR_UNKNOWN_OPERAND;
800 *error = EVAL_ERROR_MISSING_OPERAND;
805 // parse an operator and the rest of the expression
806 // precedence processing is handled here
807 static inline EVAL_NODE *parse_rest_of_expression(const char **string, int *error, EVAL_NODE *op1) {
808 EVAL_NODE *op2 = NULL;
809 unsigned char operator;
812 operator = parse_operator(string, &precedence);
815 if(operator != EVAL_OPERATOR_NOP) {
816 op2 = parse_one_full_operand(string, error);
818 // error is already reported
823 EVAL_NODE *op = eval_node_alloc(2);
824 op->operator = operator;
825 op->precedence = precedence;
827 eval_node_set_value_to_node(op, 1, op2);
829 // precedence processing
830 // if this operator has a higher precedence compared to its next
831 // put the next operator on top of us (top = evaluated later)
832 // function recursion does the rest...
833 if(op->precedence > op1->precedence && op1->count == 2 && op1->operator != '(' && op1->ops[1].type == EVAL_VALUE_EXPRESSION) {
834 eval_node_set_value_to_node(op, 0, op1->ops[1].expression);
835 op1->ops[1].expression = op;
839 eval_node_set_value_to_node(op, 0, op1);
841 return parse_rest_of_expression(string, error, op);
843 else if(**string == ')') {
847 if(op1) eval_node_free(op1);
849 *error = EVAL_ERROR_MISSING_OPERATOR;
855 // high level function to parse an expression or a sub-expression
856 static inline EVAL_NODE *parse_full_expression(const char **string, int *error) {
857 EVAL_NODE *op1 = NULL;
859 op1 = parse_one_full_operand(string, error);
861 *error = EVAL_ERROR_MISSING_OPERAND;
865 return parse_rest_of_expression(string, error, op1);
868 // ----------------------------------------------------------------------------
871 int expression_evaluate(EVAL_EXPRESSION *exp) {
872 exp->error = EVAL_ERROR_OK;
874 buffer_reset(exp->error_msg);
875 exp->result = eval_node(exp, (EVAL_NODE *)exp->nodes, &exp->error);
877 if(exp->error == EVAL_ERROR_OK)
878 exp->result = eval_check_number(exp->result, &exp->error);
880 if(exp->error != EVAL_ERROR_OK) {
883 if(buffer_strlen(exp->error_msg))
884 buffer_strcat(exp->error_msg, "; ");
886 buffer_sprintf(exp->error_msg, "failed to evaluate expression with error %d (%s)", exp->error, expression_strerror(exp->error));
893 EVAL_EXPRESSION *expression_parse(const char *string, const char **failed_at, int *error) {
894 const char *s = string;
895 int err = EVAL_ERROR_OK;
896 unsigned long pos = 0;
898 EVAL_NODE *op = parse_full_expression(&s, &err);
905 err = EVAL_ERROR_REMAINING_GARBAGE;
908 if (failed_at) *failed_at = s;
909 if (error) *error = err;
912 pos = s - string + 1;
913 error("failed to parse expression '%s': %s at character %lu (i.e.: '%s').", string, expression_strerror(err), pos, s);
917 BUFFER *out = buffer_create(1024);
918 print_parsed_as_node(out, op, &err);
919 if(err != EVAL_ERROR_OK) {
920 error("failed to re-generate expression '%s' with reason: %s", string, expression_strerror(err));
926 EVAL_EXPRESSION *exp = callocz(1, sizeof(EVAL_EXPRESSION));
928 exp->source = strdupz(string);
929 exp->parsed_as = strdupz(buffer_tostring(out));
932 exp->error_msg = buffer_create(100);
933 exp->nodes = (void *)op;
938 void expression_free(EVAL_EXPRESSION *exp) {
941 if(exp->nodes) eval_node_free((EVAL_NODE *)exp->nodes);
942 freez((void *)exp->source);
943 freez((void *)exp->parsed_as);
944 buffer_free(exp->error_msg);
948 const char *expression_strerror(int error) {
953 case EVAL_ERROR_MISSING_CLOSE_SUBEXPRESSION:
954 return "missing closing parenthesis";
956 case EVAL_ERROR_UNKNOWN_OPERAND:
957 return "unknown operand";
959 case EVAL_ERROR_MISSING_OPERAND:
960 return "expected operand";
962 case EVAL_ERROR_MISSING_OPERATOR:
963 return "expected operator";
965 case EVAL_ERROR_REMAINING_GARBAGE:
966 return "remaining characters after expression";
968 case EVAL_ERROR_INVALID_VALUE:
969 return "invalid value structure - internal error";
971 case EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS:
972 return "wrong number of operands for operation - internal error";
974 case EVAL_ERROR_VALUE_IS_NAN:
975 return "value is unset";
977 case EVAL_ERROR_VALUE_IS_INFINITE:
978 return "computed value is infinite";
980 case EVAL_ERROR_UNKNOWN_VARIABLE:
981 return "undefined variable";
984 return "unknown error";