4 #define EVAL_MAX_VARIABLE_NAME_LENGTH 300
6 typedef struct eval_variable {
10 struct eval_variable *next;
13 typedef struct eval_expression {
15 const char *parsed_as;
17 calculated_number *this;
18 calculated_number result;
26 // custom data to be used for looking up variables
27 struct rrdcalc *rrdcalc;
30 #define EVAL_VALUE_INVALID 0
31 #define EVAL_VALUE_NUMBER 1
32 #define EVAL_VALUE_VARIABLE 2
33 #define EVAL_VALUE_EXPRESSION 3
35 // parsing and evaluation
36 #define EVAL_ERROR_OK 0
39 #define EVAL_ERROR_MISSING_CLOSE_SUBEXPRESSION 1
40 #define EVAL_ERROR_UNKNOWN_OPERAND 2
41 #define EVAL_ERROR_MISSING_OPERAND 3
42 #define EVAL_ERROR_MISSING_OPERATOR 4
43 #define EVAL_ERROR_REMAINING_GARBAGE 5
46 #define EVAL_ERROR_INVALID_VALUE 101
47 #define EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS 102
48 #define EVAL_ERROR_VALUE_IS_NAN 103
49 #define EVAL_ERROR_VALUE_IS_INFINITE 104
50 #define EVAL_ERROR_UNKNOWN_VARIABLE 105
52 // parse the given string as an expression and return:
53 // a pointer to an expression if it parsed OK
54 // NULL in which case the pointer to error has the error code
55 extern EVAL_EXPRESSION *expression_parse(const char *string, const char **failed_at, int *error);
57 // free all resources allocated for an expression
58 extern void expression_free(EVAL_EXPRESSION *op);
60 // convert an error code to a message
61 extern const char *expression_strerror(int error);
63 // evaluate an expression and return
64 // 1 = OK, the result is in: expression->result
65 // 2 = FAILED, the error message is in: buffer_tostring(expression->error_msg)
66 extern int expression_evaluate(EVAL_EXPRESSION *expression);
68 #endif //NETDATA_EVAL_H