Merging upstream version 1.11.0+dfsg.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 0 insertions, 1188 deletions

diff --git a/src/eval.c b/src/eval.c
deleted file mode 100644
index 84369f6d4..000000000
--- a/src/eval.c
+++ /dev/null
@@ -1,1188 +0,0 @@
-#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 calculated_number_equal(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;
-}
-
-// 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) || !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;
-
-    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;
-
-    // AND
-    if((s[0] == 'A' || s[0] == 'a') && (s[1] == 'N' || s[1] == 'n') && (s[2] == 'D' || s[2] == 'd') && isoperatorterm_word(s[3])) {
-        *string = &s[4];
-        return 1;
-    }
-
-    // &&
-    if(s[0] == '&' && s[1] == '&' && isoperatorterm_symbol(s[2])) {
-        *string = &s[2];
-        return 1;
-    }
-
-    return 0;
-}
-
-static inline int parse_or(const char **string) {
-    const char *s = *string;
-
-    // OR
-    if((s[0] == 'O' || s[0] == 'o') && (s[1] == 'R' || s[1] == 'r') && isoperatorterm_word(s[2])) {
-        *string = &s[3];
-        return 1;
-    }
-
-    // ||
-    if(s[0] == '|' && s[1] == '|' && isoperatorterm_symbol(s[2])) {
-        *string = &s[2];
-        return 1;
-    }
-
-    return 0;
-}
-
-static inline int parse_greater_than_or_equal(const char **string) {
-    const char *s = *string;
-
-    // >=
-    if(s[0] == '>' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
-        *string = &s[2];
-        return 1;
-    }
-
-    return 0;
-}
-
-static inline int parse_less_than_or_equal(const char **string) {
-    const char *s = *string;
-
-    // <=
-    if (s[0] == '<' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
-        *string = &s[2];
-        return 1;
-    }
-
-    return 0;
-}
-
-static inline int parse_greater(const char **string) {
-    const char *s = *string;
-
-    // >
-    if(s[0] == '>' && isoperatorterm_symbol(s[1])) {
-        *string = &s[1];
-        return 1;
-    }
-
-    return 0;
-}
-
-static inline int parse_less(const char **string) {
-    const char *s = *string;
-
-    // <
-    if(s[0] == '<' && isoperatorterm_symbol(s[1])) {
-        *string = &s[1];
-        return 1;
-    }
-
-    return 0;
-}
-
-static inline int parse_equal(const char **string) {
-    const char *s = *string;
-
-    // ==
-    if(s[0] == '=' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
-        *string = &s[2];
-        return 1;
-    }
-
-    // =
-    if(s[0] == '=' && isoperatorterm_symbol(s[1])) {
-        *string = &s[1];
-        return 1;
-    }
-
-    return 0;
-}
-
-static inline int parse_not_equal(const char **string) {
-    const char *s = *string;
-
-    // !=
-    if(s[0] == '!' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
-        *string = &s[2];
-        return 1;
-    }
-
-    // <>
-    if(s[0] == '<' && s[1] == '>' && isoperatorterm_symbol(s[2])) {
-        *string = &s[2];
-    }
-
-    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;
-
-    // *
-    if(s[0] == '*' && isoperatorterm_symbol(s[1])) {
-        *string = &s[1];
-        return 1;
-    }
-
-    return 0;
-}
-
-static inline int parse_divide(const char **string) {
-    const char *s = *string;
-
-    // /
-    if(s[0] == '/' && isoperatorterm_symbol(s[1])) {
-        *string = &s[1];
-        return 1;
-    }
-
-    return 0;
-}
-
-static inline int parse_minus(const char **string) {
-    const char *s = *string;
-
-    // -
-    if(s[0] == '-' && isoperatorterm_symbol(s[1])) {
-        *string = &s[1];
-        return 1;
-    }
-
-    return 0;
-}
-
-static inline int parse_plus(const char **string) {
-    const char *s = *string;
-
-    // +
-    if(s[0] == '+' && isoperatorterm_symbol(s[1])) {
-        *string = &s[1];
-        return 1;
-    }
-
-    return 0;
-}
-
-static inline int parse_open_subexpression(const char **string) {
-    const char *s = *string;
-
-    // (
-    if(s[0] == '(') {
-        *string = &s[1];
-        return 1;
-    }
-
-    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_variable(const char **string, char *buffer, size_t len) {
-    const char *s = *string;
-
-    // $
-    if(*s == '$') {
-        size_t i = 0;
-        s++;
-
-        if(*s == '{') {
-            // ${variable_name}
-
-            s++;
-            while (*s && *s != '}' && i < len)
-                buffer[i++] = *s++;
-
-            if(*s == '}')
-                s++;
-        }
-        else {
-            // $variable_name
-
-            while (*s && !isvariableterm(*s) && i < len)
-                buffer[i++] = *s++;
-        }
-
-        buffer[i] = '\0';
-
-        if (buffer[0]) {
-            *string = s;
-            return 1;
-        }
-    }
-
-    return 0;
-}
-
-static inline int parse_constant(const char **string, calculated_number *number) {
-    char *end = NULL;
-    calculated_number n = str2ld(*string, &end);
-    if(unlikely(!end || *string == end)) {
-        *number = 0;
-        return 0;
-    }
-    *number = n;
-    *string = end;
-    return 1;
-}
-
-static inline int parse_abs(const char **string) {
-    const char *s = *string;
-
-    // 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;
-    }
-
-    return 0;
-}
-
-static inline int parse_if_then_else(const char **string) {
-    const char *s = *string;
-
-    // ?
-    if(s[0] == '?') {
-        *string = &s[1];
-        return 1;
-    }
-
-    return 0;
-}
-
-static struct operator_parser {
-    unsigned char id;
-    int (*parse)(const char **);
-} operator_parsers[] = {
-        // the order in this list is important!
-        // the first matching will be used
-        // so place the longer of overlapping ones
-        // at the top
-
-        { EVAL_OPERATOR_AND,                   parse_and },
-        { EVAL_OPERATOR_OR,                    parse_or },
-        { EVAL_OPERATOR_GREATER_THAN_OR_EQUAL, parse_greater_than_or_equal },
-        { EVAL_OPERATOR_LESS_THAN_OR_EQUAL,    parse_less_than_or_equal },
-        { EVAL_OPERATOR_NOT_EQUAL,             parse_not_equal },
-        { EVAL_OPERATOR_EQUAL,                 parse_equal },
-        { EVAL_OPERATOR_LESS,                  parse_less },
-        { EVAL_OPERATOR_GREATER,               parse_greater },
-        { EVAL_OPERATOR_PLUS,                  parse_plus },
-        { 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 in this list the following:
-         *
-         *  - NOT
-         *  - (
-         *  - )
-         *
-         * these are handled in code
-         */
-
-        // termination
-        { EVAL_OPERATOR_NOP, NULL }
-};
-
-static inline unsigned char parse_operator(const char **string, int *precedence) {
-    skip_spaces(string);
-
-    int i;
-    for(i = 0 ; operator_parsers[i].parse != NULL ; i++)
-        if(operator_parsers[i].parse(string)) {
-            if(precedence) *precedence = eval_precedence(operator_parsers[i].id);
-            return operator_parsers[i].id;
-        }
-
-    return EVAL_OPERATOR_NOP;
-}
-
-// ----------------------------------------------------------------------------
-// memory management
-
-static inline EVAL_NODE *eval_node_alloc(int count) {
-    static int id = 1;
-
-    EVAL_NODE *op = callocz(1, sizeof(EVAL_NODE) + (sizeof(EVAL_VALUE) * count));
-
-    op->id = id++;
-    op->operator = EVAL_OPERATOR_NOP;
-    op->precedence = eval_precedence(EVAL_OPERATOR_NOP);
-    op->count = count;
-    return op;
-}
-
-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].type = EVAL_VALUE_EXPRESSION;
-    op->ops[pos].expression = 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].type = EVAL_VALUE_NUMBER;
-    op->ops[pos].number = value;
-}
-
-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 eval_variable_free(EVAL_VARIABLE *v) {
-    freez(v->name);
-    freez(v);
-}
-
-static inline void eval_value_free(EVAL_VALUE *v) {
-    switch(v->type) {
-        case EVAL_VALUE_EXPRESSION:
-            eval_node_free(v->expression);
-            break;
-
-        case EVAL_VALUE_VARIABLE:
-            eval_variable_free(v->variable);
-            break;
-
-        default:
-            break;
-    }
-}
-
-static inline void eval_node_free(EVAL_NODE *op) {
-    if(op->count) {
-        int i;
-        for(i = op->count - 1; i >= 0 ;i--)
-            eval_value_free(&op->ops[i]);
-    }
-
-    freez(op);
-}
-
-// ----------------------------------------------------------------------------
-// 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_NODE *op = eval_node_alloc(1);
-    op->operator = operator_type;
-    eval_node_set_value_to_node(op, 0, sub);
-    return op;
-}
-
-// 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;
-
-    skip_spaces(string);
-    if(!(**string)) {
-        *error = EVAL_ERROR_MISSING_OPERAND;
-        return NULL;
-    }
-
-    if(parse_not(string)) {
-        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_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_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_NODE *sub = parse_full_expression(string, error);
-        if(sub) {
-            op1 = eval_node_alloc(1);
-            op1->operator = EVAL_OPERATOR_EXPRESSION_OPEN;
-            op1->precedence = eval_precedence(EVAL_OPERATOR_EXPRESSION_OPEN);
-            eval_node_set_value_to_node(op1, 0, sub);
-            if(!parse_close_subexpression(string)) {
-                *error = EVAL_ERROR_MISSING_CLOSE_SUBEXPRESSION;
-                eval_node_free(op1);
-                return NULL;
-            }
-        }
-    }
-    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)
-        *error = EVAL_ERROR_UNKNOWN_OPERAND;
-    else
-        *error = EVAL_ERROR_MISSING_OPERAND;
-
-    return op1;
-}
-
-// 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_one_full_operand(string, error);
-        if(!op2) {
-            // error is already reported
-            eval_node_free(op1);
-            return NULL;
-        }
-
-        EVAL_NODE *op = eval_node_alloc(operators[operator].parameters);
-        op->operator = operator;
-        op->precedence = precedence;
-
-        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) {
-            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_rest_of_expression(string, error, op);
-    }
-    else if(**string == ')') {
-        ;
-    }
-    else if(**string) {
-        eval_node_free(op1);
-        op1 = NULL;
-        *error = EVAL_ERROR_MISSING_OPERATOR;
-    }
-
-    return op1;
-}
-
-// 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_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 *expression_strerror(int error) {
-    switch(error) {
-        case EVAL_ERROR_OK:
-            return "success";
-
-        case EVAL_ERROR_MISSING_CLOSE_SUBEXPRESSION:
-            return "missing closing parenthesis";
-
-        case EVAL_ERROR_UNKNOWN_OPERAND:
-            return "unknown operand";
-
-        case EVAL_ERROR_MISSING_OPERAND:
-            return "expected operand";
-
-        case EVAL_ERROR_MISSING_OPERATOR:
-            return "expected operator";
-
-        case EVAL_ERROR_REMAINING_GARBAGE:
-            return "remaining characters after expression";
-
-        case EVAL_ERROR_INVALID_VALUE:
-            return "invalid value structure - internal error";
-
-        case EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS:
-            return "wrong number of operands for operation - internal error";
-
-        case EVAL_ERROR_VALUE_IS_NAN:
-            return "value is unset";
-
-        case EVAL_ERROR_VALUE_IS_INFINITE:
-            return "computed value is infinite";
-
-        case EVAL_ERROR_UNKNOWN_VARIABLE:
-            return "undefined variable";
-
-        case EVAL_ERROR_IF_THEN_ELSE_MISSING_ELSE:
-            return "missing second sub-expression of inline conditional";
-
-        default:
-            return "unknown error";
-    }
-}