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/// @file
/// @brief C analog of C++’s `std::optional`
#pragma once
#include <assert.h>
#include <stdbool.h>
#include <stddef.h>
/// a container that may or may not contain a `double` value
typedef struct {
bool has_value; ///< does this have a value?
double value; ///< the value if `has_value` is true
} optional_double_t;
/// set the value of an optional
///
/// This utility function is intended to avoid the easy typo of setting the
/// value while forgetting to set the `has_value` member.
///
/// @param me The optional whose value to set
/// @param value The value to assign
static inline void optional_double_set(optional_double_t *me, double value) {
assert(me != NULL);
me->has_value = true;
me->value = value;
}
/// get the value of an optional or a given value if the optional is empty
///
/// @param me The optional whose value to retrieve
/// @param fallback The value to return if the optional is empty
/// @return Value of the optional or `fallback` if it was empty
static inline double optional_double_value_or(optional_double_t me,
double fallback) {
if (me.has_value) {
return me.value;
}
return fallback;
}
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