diff options
Diffstat (limited to 'src/eval.c')
| -rw-r--r-- | src/eval.c | 1188 |
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"; - } -} |