#include "common.h"
+// ----------------------------------------------------------------------------
+// data structures for storing the parsed expression in memory
+
+typedef struct eval_value {
+ int type;
+
+ union {
+ calculated_number number;
+ EVAL_VARIABLE *variable;
+ struct eval_node *expression;
+ };
+} EVAL_VALUE;
+
+typedef struct eval_node {
+ int id;
+ unsigned char operator;
+ int precedence;
+
+ int count;
+ EVAL_VALUE ops[];
+} EVAL_NODE;
+
+// these are used for EVAL_NODE.operator
+// they are used as internal IDs to identify an operator
+// THEY ARE NOT USED FOR PARSING OPERATORS LIKE THAT
+#define EVAL_OPERATOR_NOP '\0'
+#define EVAL_OPERATOR_EXPRESSION_OPEN '('
+#define EVAL_OPERATOR_EXPRESSION_CLOSE ')'
+#define EVAL_OPERATOR_NOT '!'
+#define EVAL_OPERATOR_PLUS '+'
+#define EVAL_OPERATOR_MINUS '-'
+#define EVAL_OPERATOR_AND '&'
+#define EVAL_OPERATOR_OR '|'
+#define EVAL_OPERATOR_GREATER_THAN_OR_EQUAL 'G'
+#define EVAL_OPERATOR_LESS_THAN_OR_EQUAL 'L'
+#define EVAL_OPERATOR_NOT_EQUAL '~'
+#define EVAL_OPERATOR_EQUAL '='
+#define EVAL_OPERATOR_LESS '<'
+#define EVAL_OPERATOR_GREATER '>'
+#define EVAL_OPERATOR_MULTIPLY '*'
+#define EVAL_OPERATOR_DIVIDE '/'
+#define EVAL_OPERATOR_SIGN_PLUS 'P'
+#define EVAL_OPERATOR_SIGN_MINUS 'M'
+#define EVAL_OPERATOR_ABS 'A'
+#define EVAL_OPERATOR_IF_THEN_ELSE '?'
+
+// ----------------------------------------------------------------------------
+// forward function definitions
+
+static inline void eval_node_free(EVAL_NODE *op);
+static inline EVAL_NODE *parse_full_expression(const char **string, int *error);
+static inline EVAL_NODE *parse_one_full_operand(const char **string, int *error);
+static inline calculated_number eval_node(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error);
+static inline void print_parsed_as_node(BUFFER *out, EVAL_NODE *op, int *error);
+static inline void print_parsed_as_constant(BUFFER *out, calculated_number n);
+
+// ----------------------------------------------------------------------------
+// evaluation of expressions
+
+static inline calculated_number eval_variable(EVAL_EXPRESSION *exp, EVAL_VARIABLE *v, int *error) {
+ static uint32_t this_hash = 0, now_hash = 0, after_hash = 0, before_hash = 0, status_hash = 0, removed_hash = 0, uninitialized_hash = 0, undefined_hash = 0, clear_hash = 0, warning_hash = 0, critical_hash = 0;
+ calculated_number n;
+
+ if(unlikely(this_hash == 0)) {
+ this_hash = simple_hash("this");
+ now_hash = simple_hash("now");
+ after_hash = simple_hash("after");
+ before_hash = simple_hash("before");
+ status_hash = simple_hash("status");
+ removed_hash = simple_hash("REMOVED");
+ uninitialized_hash = simple_hash("UNINITIALIZED");
+ undefined_hash = simple_hash("UNDEFINED");
+ clear_hash = simple_hash("CLEAR");
+ warning_hash = simple_hash("WARNING");
+ critical_hash = simple_hash("CRITICAL");
+ }
+
+ if(unlikely(v->hash == this_hash && !strcmp(v->name, "this"))) {
+ n = (exp->this)?*exp->this:NAN;
+ buffer_strcat(exp->error_msg, "[ $this = ");
+ print_parsed_as_constant(exp->error_msg, n);
+ buffer_strcat(exp->error_msg, " ] ");
+ return n;
+ }
+
+ if(unlikely(v->hash == after_hash && !strcmp(v->name, "after"))) {
+ n = (exp->after && *exp->after)?*exp->after:NAN;
+ buffer_strcat(exp->error_msg, "[ $after = ");
+ print_parsed_as_constant(exp->error_msg, n);
+ buffer_strcat(exp->error_msg, " ] ");
+ return n;
+ }
+
+ if(unlikely(v->hash == before_hash && !strcmp(v->name, "before"))) {
+ n = (exp->before && *exp->before)?*exp->before:NAN;
+ buffer_strcat(exp->error_msg, "[ $before = ");
+ print_parsed_as_constant(exp->error_msg, n);
+ buffer_strcat(exp->error_msg, " ] ");
+ return n;
+ }
+
+ if(unlikely(v->hash == now_hash && !strcmp(v->name, "now"))) {
+ n = now_realtime_sec();
+ buffer_strcat(exp->error_msg, "[ $now = ");
+ print_parsed_as_constant(exp->error_msg, n);
+ buffer_strcat(exp->error_msg, " ] ");
+ return n;
+ }
+
+ if(unlikely(v->hash == status_hash && !strcmp(v->name, "status"))) {
+ n = (exp->status)?*exp->status:RRDCALC_STATUS_UNINITIALIZED;
+ buffer_strcat(exp->error_msg, "[ $status = ");
+ print_parsed_as_constant(exp->error_msg, n);
+ buffer_strcat(exp->error_msg, " ] ");
+ return n;
+ }
+
+ if(unlikely(v->hash == removed_hash && !strcmp(v->name, "REMOVED"))) {
+ n = RRDCALC_STATUS_REMOVED;
+ buffer_strcat(exp->error_msg, "[ $REMOVED = ");
+ print_parsed_as_constant(exp->error_msg, n);
+ buffer_strcat(exp->error_msg, " ] ");
+ return n;
+ }
+
+ if(unlikely(v->hash == uninitialized_hash && !strcmp(v->name, "UNINITIALIZED"))) {
+ n = RRDCALC_STATUS_UNINITIALIZED;
+ buffer_strcat(exp->error_msg, "[ $UNINITIALIZED = ");
+ print_parsed_as_constant(exp->error_msg, n);
+ buffer_strcat(exp->error_msg, " ] ");
+ return n;
+ }
+
+ if(unlikely(v->hash == undefined_hash && !strcmp(v->name, "UNDEFINED"))) {
+ n = RRDCALC_STATUS_UNDEFINED;
+ buffer_strcat(exp->error_msg, "[ $UNDEFINED = ");
+ print_parsed_as_constant(exp->error_msg, n);
+ buffer_strcat(exp->error_msg, " ] ");
+ return n;
+ }
+
+ if(unlikely(v->hash == clear_hash && !strcmp(v->name, "CLEAR"))) {
+ n = RRDCALC_STATUS_CLEAR;
+ buffer_strcat(exp->error_msg, "[ $CLEAR = ");
+ print_parsed_as_constant(exp->error_msg, n);
+ buffer_strcat(exp->error_msg, " ] ");
+ return n;
+ }
+
+ if(unlikely(v->hash == warning_hash && !strcmp(v->name, "WARNING"))) {
+ n = RRDCALC_STATUS_WARNING;
+ buffer_strcat(exp->error_msg, "[ $WARNING = ");
+ print_parsed_as_constant(exp->error_msg, n);
+ buffer_strcat(exp->error_msg, " ] ");
+ return n;
+ }
+
+ if(unlikely(v->hash == critical_hash && !strcmp(v->name, "CRITICAL"))) {
+ n = RRDCALC_STATUS_CRITICAL;
+ buffer_strcat(exp->error_msg, "[ $CRITICAL = ");
+ print_parsed_as_constant(exp->error_msg, n);
+ buffer_strcat(exp->error_msg, " ] ");
+ return n;
+ }
+
+ if(exp->rrdcalc && health_variable_lookup(v->name, v->hash, exp->rrdcalc, &n)) {
+ buffer_sprintf(exp->error_msg, "[ $%s = ", v->name);
+ print_parsed_as_constant(exp->error_msg, n);
+ buffer_strcat(exp->error_msg, " ] ");
+ return n;
+ }
+
+ *error = EVAL_ERROR_UNKNOWN_VARIABLE;
+ buffer_sprintf(exp->error_msg, "[ undefined variable '%s' ] ", v->name);
+ return 0;
+}
+
+static inline calculated_number eval_value(EVAL_EXPRESSION *exp, EVAL_VALUE *v, int *error) {
+ calculated_number n;
+
+ switch(v->type) {
+ case EVAL_VALUE_EXPRESSION:
+ n = eval_node(exp, v->expression, error);
+ break;
+
+ case EVAL_VALUE_NUMBER:
+ n = v->number;
+ break;
+
+ case EVAL_VALUE_VARIABLE:
+ n = eval_variable(exp, v->variable, error);
+ break;
+
+ default:
+ *error = EVAL_ERROR_INVALID_VALUE;
+ n = 0;
+ break;
+ }
+
+ return n;
+}
+
+static inline int is_true(calculated_number n) {
+ if(isnan(n)) return 0;
+ if(isinf(n)) return 1;
+ if(n == 0) return 0;
+ return 1;
+}
+
+calculated_number eval_and(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ return is_true(eval_value(exp, &op->ops[0], error)) && is_true(eval_value(exp, &op->ops[1], error));
+}
+calculated_number eval_or(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ return is_true(eval_value(exp, &op->ops[0], error)) || is_true(eval_value(exp, &op->ops[1], error));
+}
+calculated_number eval_greater_than_or_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ calculated_number n1 = eval_value(exp, &op->ops[0], error);
+ calculated_number n2 = eval_value(exp, &op->ops[1], error);
+ return isgreaterequal(n1, n2);
+}
+calculated_number eval_less_than_or_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ calculated_number n1 = eval_value(exp, &op->ops[0], error);
+ calculated_number n2 = eval_value(exp, &op->ops[1], error);
+ return islessequal(n1, n2);
+}
+calculated_number eval_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ calculated_number n1 = eval_value(exp, &op->ops[0], error);
+ calculated_number n2 = eval_value(exp, &op->ops[1], error);
+ if(isnan(n1) && isnan(n2)) return 1;
+ if(isinf(n1) && isinf(n2)) return 1;
+ if(isnan(n1) || isnan(n2)) return 0;
+ if(isinf(n1) || isinf(n2)) return 0;
+ return n1 == n2;
+}
+calculated_number eval_not_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ return !eval_equal(exp, op, error);
+}
+calculated_number eval_less(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ calculated_number n1 = eval_value(exp, &op->ops[0], error);
+ calculated_number n2 = eval_value(exp, &op->ops[1], error);
+ return isless(n1, n2);
+}
+calculated_number eval_greater(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ calculated_number n1 = eval_value(exp, &op->ops[0], error);
+ calculated_number n2 = eval_value(exp, &op->ops[1], error);
+ return isgreater(n1, n2);
+}
+calculated_number eval_plus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ calculated_number n1 = eval_value(exp, &op->ops[0], error);
+ calculated_number n2 = eval_value(exp, &op->ops[1], error);
+ if(isnan(n1) || isnan(n2)) return NAN;
+ if(isinf(n1) || isinf(n2)) return INFINITY;
+ return n1 + n2;
+}
+calculated_number eval_minus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ calculated_number n1 = eval_value(exp, &op->ops[0], error);
+ calculated_number n2 = eval_value(exp, &op->ops[1], error);
+ if(isnan(n1) || isnan(n2)) return NAN;
+ if(isinf(n1) || isinf(n2)) return INFINITY;
+ return n1 - n2;
+}
+calculated_number eval_multiply(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ calculated_number n1 = eval_value(exp, &op->ops[0], error);
+ calculated_number n2 = eval_value(exp, &op->ops[1], error);
+ if(isnan(n1) || isnan(n2)) return NAN;
+ if(isinf(n1) || isinf(n2)) return INFINITY;
+ return n1 * n2;
+}
+calculated_number eval_divide(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ calculated_number n1 = eval_value(exp, &op->ops[0], error);
+ calculated_number n2 = eval_value(exp, &op->ops[1], error);
+ if(isnan(n1) || isnan(n2)) return NAN;
+ if(isinf(n1) || isinf(n2)) return INFINITY;
+ return n1 / n2;
+}
+calculated_number eval_nop(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ return eval_value(exp, &op->ops[0], error);
+}
+calculated_number eval_not(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ return !is_true(eval_value(exp, &op->ops[0], error));
+}
+calculated_number eval_sign_plus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ return eval_value(exp, &op->ops[0], error);
+}
+calculated_number eval_sign_minus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ calculated_number n1 = eval_value(exp, &op->ops[0], error);
+ if(isnan(n1)) return NAN;
+ if(isinf(n1)) return INFINITY;
+ return -n1;
+}
+calculated_number eval_abs(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ calculated_number n1 = eval_value(exp, &op->ops[0], error);
+ if(isnan(n1)) return NAN;
+ if(isinf(n1)) return INFINITY;
+ return abs(n1);
+}
+calculated_number eval_if_then_else(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ if(is_true(eval_value(exp, &op->ops[0], error)))
+ return eval_value(exp, &op->ops[1], error);
+ else
+ return eval_value(exp, &op->ops[2], error);
+}
+
+static struct operator {
+ const char *print_as;
+ char precedence;
+ char parameters;
+ char isfunction;
+ calculated_number (*eval)(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error);
+} operators[256] = {
+ // this is a random access array
+ // we always access it with a known EVAL_OPERATOR_X
+
+ [EVAL_OPERATOR_AND] = { "&&", 2, 2, 0, eval_and },
+ [EVAL_OPERATOR_OR] = { "||", 2, 2, 0, eval_or },
+ [EVAL_OPERATOR_GREATER_THAN_OR_EQUAL] = { ">=", 3, 2, 0, eval_greater_than_or_equal },
+ [EVAL_OPERATOR_LESS_THAN_OR_EQUAL] = { "<=", 3, 2, 0, eval_less_than_or_equal },
+ [EVAL_OPERATOR_NOT_EQUAL] = { "!=", 3, 2, 0, eval_not_equal },
+ [EVAL_OPERATOR_EQUAL] = { "==", 3, 2, 0, eval_equal },
+ [EVAL_OPERATOR_LESS] = { "<", 3, 2, 0, eval_less },
+ [EVAL_OPERATOR_GREATER] = { ">", 3, 2, 0, eval_greater },
+ [EVAL_OPERATOR_PLUS] = { "+", 4, 2, 0, eval_plus },
+ [EVAL_OPERATOR_MINUS] = { "-", 4, 2, 0, eval_minus },
+ [EVAL_OPERATOR_MULTIPLY] = { "*", 5, 2, 0, eval_multiply },
+ [EVAL_OPERATOR_DIVIDE] = { "/", 5, 2, 0, eval_divide },
+ [EVAL_OPERATOR_NOT] = { "!", 6, 1, 0, eval_not },
+ [EVAL_OPERATOR_SIGN_PLUS] = { "+", 6, 1, 0, eval_sign_plus },
+ [EVAL_OPERATOR_SIGN_MINUS] = { "-", 6, 1, 0, eval_sign_minus },
+ [EVAL_OPERATOR_ABS] = { "abs(",6,1, 1, eval_abs },
+ [EVAL_OPERATOR_IF_THEN_ELSE] = { "?", 7, 3, 0, eval_if_then_else },
+ [EVAL_OPERATOR_NOP] = { NULL, 8, 1, 0, eval_nop },
+ [EVAL_OPERATOR_EXPRESSION_OPEN] = { NULL, 8, 1, 0, eval_nop },
+
+ // this should exist in our evaluation list
+ [EVAL_OPERATOR_EXPRESSION_CLOSE] = { NULL, 99, 1, 0, eval_nop }
+};
+
+#define eval_precedence(operator) (operators[(unsigned char)(operator)].precedence)
+
+static inline calculated_number eval_node(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
+ if(unlikely(op->count != operators[op->operator].parameters)) {
+ *error = EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS;
+ return 0;
+ }
+
+ calculated_number n = operators[op->operator].eval(exp, op, error);
+
+ return n;
+}
+
+// ----------------------------------------------------------------------------
+// parsed-as generation
+
+static inline void print_parsed_as_variable(BUFFER *out, EVAL_VARIABLE *v, int *error) {
+ (void)error;
+ buffer_sprintf(out, "$%s", v->name);
+}
+
+static inline void print_parsed_as_constant(BUFFER *out, calculated_number n) {
+ if(unlikely(isnan(n))) {
+ buffer_strcat(out, "nan");
+ return;
+ }
+
+ if(unlikely(isinf(n))) {
+ buffer_strcat(out, "inf");
+ return;
+ }
+
+ char b[100+1], *s;
+ snprintfz(b, 100, CALCULATED_NUMBER_FORMAT, n);
+
+ s = &b[strlen(b) - 1];
+ while(s > b && *s == '0') {
+ *s ='\0';
+ s--;
+ }
+
+ if(s > b && *s == '.')
+ *s = '\0';
+
+ buffer_strcat(out, b);
+}
+
+static inline void print_parsed_as_value(BUFFER *out, EVAL_VALUE *v, int *error) {
+ switch(v->type) {
+ case EVAL_VALUE_EXPRESSION:
+ print_parsed_as_node(out, v->expression, error);
+ break;
+
+ case EVAL_VALUE_NUMBER:
+ print_parsed_as_constant(out, v->number);
+ break;
+
+ case EVAL_VALUE_VARIABLE:
+ print_parsed_as_variable(out, v->variable, error);
+ break;
+
+ default:
+ *error = EVAL_ERROR_INVALID_VALUE;
+ break;
+ }
+}
+
+static inline void print_parsed_as_node(BUFFER *out, EVAL_NODE *op, int *error) {
+ if(unlikely(op->count != operators[op->operator].parameters)) {
+ *error = EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS;
+ return;
+ }
+
+ if(operators[op->operator].parameters == 1) {
+
+ if(operators[op->operator].print_as)
+ buffer_sprintf(out, "%s", operators[op->operator].print_as);
+
+ //if(op->operator == EVAL_OPERATOR_EXPRESSION_OPEN)
+ // buffer_strcat(out, "(");
+
+ print_parsed_as_value(out, &op->ops[0], error);
+
+ //if(op->operator == EVAL_OPERATOR_EXPRESSION_OPEN)
+ // buffer_strcat(out, ")");
+ }
+
+ else if(operators[op->operator].parameters == 2) {
+ buffer_strcat(out, "(");
+ print_parsed_as_value(out, &op->ops[0], error);
+
+ if(operators[op->operator].print_as)
+ buffer_sprintf(out, " %s ", operators[op->operator].print_as);
+
+ print_parsed_as_value(out, &op->ops[1], error);
+ buffer_strcat(out, ")");
+ }
+ else if(op->operator == EVAL_OPERATOR_IF_THEN_ELSE && operators[op->operator].parameters == 3) {
+ buffer_strcat(out, "(");
+ print_parsed_as_value(out, &op->ops[0], error);
+
+ if(operators[op->operator].print_as)
+ buffer_sprintf(out, " %s ", operators[op->operator].print_as);
+
+ print_parsed_as_value(out, &op->ops[1], error);
+ buffer_strcat(out, " : ");
+ print_parsed_as_value(out, &op->ops[2], error);
+ buffer_strcat(out, ")");
+ }
+
+ if(operators[op->operator].isfunction)
+ buffer_strcat(out, ")");
+}
+
+// ----------------------------------------------------------------------------
+// parsing expressions
+
+// skip spaces
static inline void skip_spaces(const char **string) {
const char *s = *string;
while(isspace(*s)) s++;
*string = s;
}
-// ----------------------------------------------------------------------------
-// operators that work on 2 operands
-
+// what character can appear just after an operator keyword
+// like NOT AND OR ?
static inline int isoperatorterm_word(const char s) {
- if(isspace(s) || s == '(' || s == '$' || s == '!' || s == '-' || s == '+' || isdigit(s)) return 1;
+ if(isspace(s) || s == '(' || s == '$' || s == '!' || s == '-' || s == '+' || isdigit(s) || !s)
+ return 1;
+
return 0;
}
+// what character can appear just after an operator symbol?
static inline int isoperatorterm_symbol(const char s) {
- if(isoperatorterm_word(s) || isalpha(s)) return 1;
+ if(isoperatorterm_word(s) || isalpha(s))
+ return 1;
+
return 0;
}
+// return 1 if the character should never appear in a variable
+static inline int isvariableterm(const char s) {
+ if(isalnum(s) || s == '.' || s == '_')
+ return 0;
+
+ return 1;
+}
+
+// ----------------------------------------------------------------------------
+// parse operators
+
static inline int parse_and(const char **string) {
const char *s = *string;
return 0;
}
+static inline int parse_not(const char **string) {
+ const char *s = *string;
+
+ // NOT
+ if((s[0] == 'N' || s[0] == 'n') && (s[1] == 'O' || s[1] == 'o') && (s[2] == 'T' || s[2] == 't') && isoperatorterm_word(s[3])) {
+ *string = &s[3];
+ return 1;
+ }
+
+ if(s[0] == '!') {
+ *string = &s[1];
+ return 1;
+ }
+
+ return 0;
+}
+
static inline int parse_multiply(const char **string) {
const char *s = *string;
return 0;
}
+#define parse_close_function(x) parse_close_subexpression(x)
+
static inline int parse_close_subexpression(const char **string) {
const char *s = *string;
- // (
+ // )
if(s[0] == ')') {
*string = &s[1];
return 1;
return 0;
}
-static inline int parse_literal(const char **string, calculated_number *number) {
- char *end = NULL;
- *number = strtold(*string, &end);
- if(!end || *string == end) return 0;
+static inline int parse_variable(const char **string, char *buffer, size_t len) {
+ const char *s = *string;
+
+ // $
+ if(s[0] == '$') {
+ size_t i = 0;
+ s++;
+
+ while(*s && !isvariableterm(*s) && i < len)
+ buffer[i++] = *s++;
+
+ buffer[i] = '\0';
+
+ if(buffer[0]) {
+ *string = &s[0];
+ return 1;
+ }
+ }
+ return 0;
+}
+
+static inline int parse_constant(const char **string, calculated_number *number) {
+ char *end = NULL;
+ calculated_number n = strtold(*string, &end);
+ if(unlikely(!end || *string == end)) {
+ *number = 0;
+ return 0;
+ }
+ *number = n;
*string = end;
return 1;
}
-// ----------------------------------------------------------------------------
-// operators that affect a single operand
-
-static inline int parse_not(const char **string) {
+static inline int parse_abs(const char **string) {
const char *s = *string;
- // NOT
- if((s[0] == 'N' || s[0] == 'n') && (s[1] == 'O' || s[1] == 'o') && (s[2] == 'T' || s[2] == 't') && isoperatorterm_word(s[3])) {
+ // ABS
+ if((s[0] == 'A' || s[0] == 'a') && (s[1] == 'B' || s[1] == 'b') && (s[2] == 'S' || s[2] == 's') && s[3] == '(') {
*string = &s[3];
return 1;
}
- if(s[0] == EVAL_OPERATOR_NOT) {
+ return 0;
+}
+
+static inline int parse_if_then_else(const char **string) {
+ const char *s = *string;
+
+ // ?
+ if(s[0] == '?') {
*string = &s[1];
return 1;
}
}
static struct operator_parser {
- char id;
+ unsigned char id;
int (*parse)(const char **);
} operator_parsers[] = {
// the order in this list is important!
{ EVAL_OPERATOR_MINUS, parse_minus },
{ EVAL_OPERATOR_MULTIPLY, parse_multiply },
{ EVAL_OPERATOR_DIVIDE, parse_divide },
+ { EVAL_OPERATOR_IF_THEN_ELSE, parse_if_then_else },
- /* we should not put
+ /* we should not put in this list the following:
*
* - NOT
* - (
* - )
*
- * in this list
+ * these are handled in code
*/
+ // termination
{ EVAL_OPERATOR_NOP, NULL }
};
-// ----------------------------------------------------------------------------
-// evaluation of operations
-
-calculated_number eval_and(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_or(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_greater_than_or_equal(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_less_than_or_equal(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_not_equal(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_equal(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_less(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_greater(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_plus(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_minus(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_multiply(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_divide(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_nop(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_not(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_sign_plus(EVAL_OPERAND *op) {
- return 0;
-}
-calculated_number eval_sign_minus(EVAL_OPERAND *op) {
- return 0;
-}
-
-static struct operator {
- const char *print_as;
- char precedence;
- calculated_number (*eval)(EVAL_OPERAND *op);
-} operators[256] = {
- // this is a random access array
- // we always access it with a known EVAL_OPERATOR_X
-
- [EVAL_OPERATOR_AND] = { "&&", 2, eval_and },
- [EVAL_OPERATOR_OR] = { "||", 2, eval_or },
- [EVAL_OPERATOR_GREATER_THAN_OR_EQUAL] = { ">=", 3, eval_greater_than_or_equal },
- [EVAL_OPERATOR_LESS_THAN_OR_EQUAL] = { "<=", 3, eval_less_than_or_equal },
- [EVAL_OPERATOR_NOT_EQUAL] = { "!=", 3, eval_not_equal },
- [EVAL_OPERATOR_EQUAL] = { "==", 3, eval_equal },
- [EVAL_OPERATOR_LESS] = { "<", 3, eval_less },
- [EVAL_OPERATOR_GREATER] = { ">", 3, eval_greater },
- [EVAL_OPERATOR_PLUS] = { "+", 4, eval_plus },
- [EVAL_OPERATOR_MINUS] = { "-", 4, eval_minus },
- [EVAL_OPERATOR_MULTIPLY] = { "*", 5, eval_multiply },
- [EVAL_OPERATOR_DIVIDE] = { "/", 5, eval_divide },
- [EVAL_OPERATOR_NOT] = { "!", 6, eval_not },
- [EVAL_OPERATOR_SIGN_PLUS] = { "+", 6, eval_sign_plus },
- [EVAL_OPERATOR_SIGN_MINUS] = { "-", 6, eval_sign_minus },
- [EVAL_OPERATOR_NOP] = { NULL, 7, eval_nop },
- [EVAL_OPERATOR_VALUE] = { NULL, 7, eval_nop },
- [EVAL_OPERATOR_EXPRESSION_OPEN] = { "(", 7, eval_nop },
-
- // this should exist in our evaluation list
- [EVAL_OPERATOR_EXPRESSION_CLOSE] = { ")", 7, eval_nop }
-};
-
-#define eval_precedence(operator) (operators[(unsigned char)(operator)].precedence)
-
-// ----------------------------------------------------------------------------
-
-static inline char parse_operator(const char **string, int *precedence) {
+static inline unsigned char parse_operator(const char **string, int *precedence) {
skip_spaces(string);
int i;
return EVAL_OPERATOR_NOP;
}
+// ----------------------------------------------------------------------------
+// memory management
-static inline EVAL_OPERAND *operand_alloc(int count) {
+static inline EVAL_NODE *eval_node_alloc(int count) {
static int id = 1;
- EVAL_OPERAND *op = calloc(1, sizeof(EVAL_OPERAND) + (sizeof(EVAL_VALUE) * count));
- if(!op) fatal("Cannot allocate memory for OPERAND with %d slots", count);
+ EVAL_NODE *op = callocz(1, sizeof(EVAL_NODE) + (sizeof(EVAL_VALUE) * count));
op->id = id++;
op->operator = EVAL_OPERATOR_NOP;
return op;
}
-static inline void operand_set_value_operand(EVAL_OPERAND *op, int pos, EVAL_OPERAND *value) {
+static inline void eval_node_set_value_to_node(EVAL_NODE *op, int pos, EVAL_NODE *value) {
if(pos >= op->count)
fatal("Invalid request to set position %d of OPERAND that has only %d values", pos + 1, op->count + 1);
op->ops[pos].expression = value;
}
-static inline void operand_set_value_literal(EVAL_OPERAND *op, int pos, calculated_number value) {
+static inline void eval_node_set_value_to_constant(EVAL_NODE *op, int pos, calculated_number value) {
if(pos >= op->count)
fatal("Invalid request to set position %d of OPERAND that has only %d values", pos + 1, op->count + 1);
op->ops[pos].number = value;
}
-// forward definitions
-static inline void operand_free(EVAL_OPERAND *op);
-static inline EVAL_OPERAND *parse_operand(const char **string, int *error);
-static inline EVAL_OPERAND *parse_operand1(const char **string, int *error);
+static inline void eval_node_set_value_to_variable(EVAL_NODE *op, int pos, const char *variable) {
+ if(pos >= op->count)
+ fatal("Invalid request to set position %d of OPERAND that has only %d values", pos + 1, op->count + 1);
+
+ op->ops[pos].type = EVAL_VALUE_VARIABLE;
+ op->ops[pos].variable = callocz(1, sizeof(EVAL_VARIABLE));
+ op->ops[pos].variable->name = strdupz(variable);
+ op->ops[pos].variable->hash = simple_hash(op->ops[pos].variable->name);
+}
-static inline void variable_free(VARIABLE *v) {
- free(v);
+static inline void eval_variable_free(EVAL_VARIABLE *v) {
+ freez(v->name);
+ freez(v);
}
-static inline void value_free(EVAL_VALUE *v) {
+static inline void eval_value_free(EVAL_VALUE *v) {
switch(v->type) {
case EVAL_VALUE_EXPRESSION:
- operand_free(v->expression);
+ eval_node_free(v->expression);
break;
case EVAL_VALUE_VARIABLE:
- variable_free(v->variable);
+ eval_variable_free(v->variable);
break;
default:
}
}
-static inline void operand_free(EVAL_OPERAND *op) {
+static inline void eval_node_free(EVAL_NODE *op) {
if(op->count) {
int i;
for(i = op->count - 1; i >= 0 ;i--)
- value_free(&op->ops[i]);
+ eval_value_free(&op->ops[i]);
}
- free(op);
+ freez(op);
}
-static inline EVAL_OPERAND *parse_operand_with_operator(const char **string, char type, int *error) {
- EVAL_OPERAND *sub = parse_operand1(string, error);
+// ----------------------------------------------------------------------------
+// the parsing logic
+
+// helper function to avoid allocations all over the place
+static inline EVAL_NODE *parse_next_operand_given_its_operator(const char **string, unsigned char operator_type, int *error) {
+ EVAL_NODE *sub = parse_one_full_operand(string, error);
if(!sub) return NULL;
- EVAL_OPERAND *op = operand_alloc(1);
- op->operator = type;
- operand_set_value_operand(op, 0, sub);
+ EVAL_NODE *op = eval_node_alloc(1);
+ op->operator = operator_type;
+ eval_node_set_value_to_node(op, 0, sub);
return op;
}
-static inline EVAL_OPERAND *parse_operand1(const char **string, int *error) {
- EVAL_OPERAND *op1 = NULL;
+// parse a full operand, including its sign or other associative operator (e.g. NOT)
+static inline EVAL_NODE *parse_one_full_operand(const char **string, int *error) {
+ char variable_buffer[EVAL_MAX_VARIABLE_NAME_LENGTH + 1];
+ EVAL_NODE *op1 = NULL;
calculated_number number;
*error = EVAL_ERROR_OK;
}
if(parse_not(string)) {
- op1 = parse_operand_with_operator(string, EVAL_OPERATOR_NOT, error);
+ op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_NOT, error);
op1->precedence = eval_precedence(EVAL_OPERATOR_NOT);
}
else if(parse_plus(string)) {
- op1 = parse_operand_with_operator(string, EVAL_OPERATOR_SIGN_PLUS, error);
+ op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_SIGN_PLUS, error);
op1->precedence = eval_precedence(EVAL_OPERATOR_SIGN_PLUS);
}
else if(parse_minus(string)) {
- op1 = parse_operand_with_operator(string, EVAL_OPERATOR_SIGN_MINUS, error);
+ op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_SIGN_MINUS, error);
op1->precedence = eval_precedence(EVAL_OPERATOR_SIGN_MINUS);
}
+ else if(parse_abs(string)) {
+ op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_ABS, error);
+ op1->precedence = eval_precedence(EVAL_OPERATOR_ABS);
+ }
else if(parse_open_subexpression(string)) {
- EVAL_OPERAND *sub = parse_operand(string, error);
+ EVAL_NODE *sub = parse_full_expression(string, error);
if(sub) {
- op1 = operand_alloc(1);
+ op1 = eval_node_alloc(1);
op1->operator = EVAL_OPERATOR_EXPRESSION_OPEN;
op1->precedence = eval_precedence(EVAL_OPERATOR_EXPRESSION_OPEN);
- operand_set_value_operand(op1, 0, sub);
+ eval_node_set_value_to_node(op1, 0, sub);
if(!parse_close_subexpression(string)) {
*error = EVAL_ERROR_MISSING_CLOSE_SUBEXPRESSION;
- operand_free(op1);
+ eval_node_free(op1);
return NULL;
}
}
}
-// else if(parse_variable(string)) {
-//
-// }
- else if(parse_literal(string, &number)) {
- op1 = operand_alloc(1);
- op1->operator = EVAL_OPERATOR_VALUE;
- operand_set_value_literal(op1, 0, number);
+ else if(parse_variable(string, variable_buffer, EVAL_MAX_VARIABLE_NAME_LENGTH)) {
+ op1 = eval_node_alloc(1);
+ op1->operator = EVAL_OPERATOR_NOP;
+ eval_node_set_value_to_variable(op1, 0, variable_buffer);
+ }
+ else if(parse_constant(string, &number)) {
+ op1 = eval_node_alloc(1);
+ op1->operator = EVAL_OPERATOR_NOP;
+ eval_node_set_value_to_constant(op1, 0, number);
}
- else if(*string)
+ else if(**string)
*error = EVAL_ERROR_UNKNOWN_OPERAND;
else
*error = EVAL_ERROR_MISSING_OPERAND;
return op1;
}
-static inline EVAL_OPERAND *parse_operand_rest(const char **string, int *error, EVAL_OPERAND *op1) {
- EVAL_OPERAND *op2 = NULL;
- char operator;
+// parse an operator and the rest of the expression
+// precedence processing is handled here
+static inline EVAL_NODE *parse_rest_of_expression(const char **string, int *error, EVAL_NODE *op1) {
+ EVAL_NODE *op2 = NULL;
+ unsigned char operator;
int precedence;
operator = parse_operator(string, &precedence);
skip_spaces(string);
if(operator != EVAL_OPERATOR_NOP) {
- op2 = parse_operand1(string, error);
+ op2 = parse_one_full_operand(string, error);
if(!op2) {
- operand_free(op1);
+ // error is already reported
+ eval_node_free(op1);
return NULL;
}
- EVAL_OPERAND *op = operand_alloc(2);
+ EVAL_NODE *op = eval_node_alloc(operators[operator].parameters);
op->operator = operator;
op->precedence = precedence;
- operand_set_value_operand(op, 0, op1);
- operand_set_value_operand(op, 1, op2);
+ if(operator == EVAL_OPERATOR_IF_THEN_ELSE && op->count == 3) {
+ skip_spaces(string);
+
+ if(**string != ':') {
+ eval_node_free(op);
+ eval_node_free(op1);
+ eval_node_free(op2);
+ *error = EVAL_ERROR_IF_THEN_ELSE_MISSING_ELSE;
+ return NULL;
+ }
+ (*string)++;
+
+ skip_spaces(string);
+
+ EVAL_NODE *op3 = parse_one_full_operand(string, error);
+ if(!op3) {
+ eval_node_free(op);
+ eval_node_free(op1);
+ eval_node_free(op2);
+ // error is already reported
+ return NULL;
+ }
+
+ eval_node_set_value_to_node(op, 2, op3);
+ }
+
+ eval_node_set_value_to_node(op, 1, op2);
+ // precedence processing
+ // if this operator has a higher precedence compared to its next
+ // put the next operator on top of us (top = evaluated later)
+ // function recursion does the rest...
if(op->precedence > op1->precedence && op1->count == 2 && op1->operator != '(' && op1->ops[1].type == EVAL_VALUE_EXPRESSION) {
- operand_set_value_operand(op, 0, op1->ops[1].expression);
+ eval_node_set_value_to_node(op, 0, op1->ops[1].expression);
op1->ops[1].expression = op;
op = op1;
}
+ else
+ eval_node_set_value_to_node(op, 0, op1);
- return parse_operand_rest(string, error, op);
+ return parse_rest_of_expression(string, error, op);
}
- else if(**string == EVAL_OPERATOR_EXPRESSION_CLOSE) {
+ else if(**string == ')') {
;
}
else if(**string) {
- if(op1) operand_free(op1);
+ eval_node_free(op1);
op1 = NULL;
*error = EVAL_ERROR_MISSING_OPERATOR;
}
return op1;
}
-static inline EVAL_OPERAND *parse_operand(const char **string, int *error) {
- EVAL_OPERAND *op1 = NULL;
-
- op1 = parse_operand1(string, error);
+// high level function to parse an expression or a sub-expression
+static inline EVAL_NODE *parse_full_expression(const char **string, int *error) {
+ EVAL_NODE *op1 = parse_one_full_operand(string, error);
if(!op1) {
*error = EVAL_ERROR_MISSING_OPERAND;
return NULL;
}
- return parse_operand_rest(string, error, op1);
+ return parse_rest_of_expression(string, error, op1);
+}
+
+// ----------------------------------------------------------------------------
+// public API
+
+int expression_evaluate(EVAL_EXPRESSION *exp) {
+ exp->error = EVAL_ERROR_OK;
+
+ buffer_reset(exp->error_msg);
+ exp->result = eval_node(exp, (EVAL_NODE *)exp->nodes, &exp->error);
+
+ if(unlikely(isnan(exp->result))) {
+ if(exp->error == EVAL_ERROR_OK)
+ exp->error = EVAL_ERROR_VALUE_IS_NAN;
+ }
+ else if(unlikely(isinf(exp->result))) {
+ if(exp->error == EVAL_ERROR_OK)
+ exp->error = EVAL_ERROR_VALUE_IS_INFINITE;
+ }
+ else if(unlikely(exp->error == EVAL_ERROR_UNKNOWN_VARIABLE)) {
+ // although there is an unknown variable
+ // the expression was evaluated successfully
+ exp->error = EVAL_ERROR_OK;
+ }
+
+ if(exp->error != EVAL_ERROR_OK) {
+ exp->result = NAN;
+
+ if(buffer_strlen(exp->error_msg))
+ buffer_strcat(exp->error_msg, "; ");
+
+ buffer_sprintf(exp->error_msg, "failed to evaluate expression with error %d (%s)", exp->error, expression_strerror(exp->error));
+ return 0;
+ }
+
+ return 1;
+}
+
+EVAL_EXPRESSION *expression_parse(const char *string, const char **failed_at, int *error) {
+ const char *s = string;
+ int err = EVAL_ERROR_OK;
+
+ EVAL_NODE *op = parse_full_expression(&s, &err);
+
+ if(*s) {
+ if(op) {
+ eval_node_free(op);
+ op = NULL;
+ }
+ err = EVAL_ERROR_REMAINING_GARBAGE;
+ }
+
+ if (failed_at) *failed_at = s;
+ if (error) *error = err;
+
+ if(!op) {
+ unsigned long pos = s - string + 1;
+ error("failed to parse expression '%s': %s at character %lu (i.e.: '%s').", string, expression_strerror(err), pos, s);
+ return NULL;
+ }
+
+ BUFFER *out = buffer_create(1024);
+ print_parsed_as_node(out, op, &err);
+ if(err != EVAL_ERROR_OK) {
+ error("failed to re-generate expression '%s' with reason: %s", string, expression_strerror(err));
+ eval_node_free(op);
+ buffer_free(out);
+ return NULL;
+ }
+
+ EVAL_EXPRESSION *exp = callocz(1, sizeof(EVAL_EXPRESSION));
+
+ exp->source = strdupz(string);
+ exp->parsed_as = strdupz(buffer_tostring(out));
+ buffer_free(out);
+
+ exp->error_msg = buffer_create(100);
+ exp->nodes = (void *)op;
+
+ return exp;
+}
+
+void expression_free(EVAL_EXPRESSION *exp) {
+ if(!exp) return;
+
+ if(exp->nodes) eval_node_free((EVAL_NODE *)exp->nodes);
+ freez((void *)exp->source);
+ freez((void *)exp->parsed_as);
+ buffer_free(exp->error_msg);
+ freez(exp);
}
-const char *eval_error(int error) {
+const char *expression_strerror(int error) {
switch(error) {
case EVAL_ERROR_OK:
return "success";
case EVAL_ERROR_MISSING_OPERATOR:
return "expected operator";
- default:
- return "unknown error";
- }
-}
+ case EVAL_ERROR_REMAINING_GARBAGE:
+ return "remaining characters after expression";
-EVAL_OPERAND *parse_expression(const char *string, const char **failed_at, int *error) {
- const char *s;
- int err = EVAL_ERROR_OK;
- unsigned long pos = 0;
+ case EVAL_ERROR_INVALID_VALUE:
+ return "invalid value structure - internal error";
- s = string;
- EVAL_OPERAND *op = parse_operand(&s, &err);
+ case EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS:
+ return "wrong number of operands for operation - internal error";
- if (failed_at) *failed_at = s;
- if (error) *error = err;
+ case EVAL_ERROR_VALUE_IS_NAN:
+ return "value is unset";
- if(!op) {
- pos = s - string + 1;
- error("failed to parse expression '%s': %s at character %lu (i.e.: '%s').", string, eval_error(err), pos, s);
- }
+ case EVAL_ERROR_VALUE_IS_INFINITE:
+ return "computed value is infinite";
- return op;
-}
+ case EVAL_ERROR_UNKNOWN_VARIABLE:
+ return "undefined variable";
+
+ case EVAL_ERROR_IF_THEN_ELSE_MISSING_ELSE:
+ return "missing second sub-expression of inline conditional";
-void free_expression(EVAL_OPERAND *op) {
- if(op) operand_free(op);
+ default:
+ return "unknown error";
+ }
}
projects / netdata.git / blobdiff