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#ifndef COMSERVATORY_CREATOR_HPP
#define COMSERVATORY_CREATOR_HPP
#include <stdexcept>
#include "Field.hpp"
/**
* @file Creator.hpp
*
* @brief Defines the `FieldCreator` class and defaults.
*/
namespace comservatory {
/**
* @brief Virtual base class for a `Field` creator.
*
* Applications may define concrete subclasses to control how `Field`s are created during parsing of the CSV.
* This involves specializing the `create()` method, possibly with custom `Field` subclasses backed by a different memory mechanism.
* In this manner, developers can directly stream the CSV into their memory layout rather than going through a `FilledField` intermediate.
*/
struct FieldCreator {
/**
* @param t Type of the field.
* @param n Number of existing (missing) records in the field.
* This should be used to specify that the first `n` values of the field's contents are missing.
* @param dummy Whether to create a dummy field.
* This is used to create placeholders for fields that are not of interest when `ReadOptions::keep_subset` is set,
* i.e., not in `ReadOptions::keep_subset_names` or `ReadOptions::keep_subset_indices`.
*
* @return An appropriate instance of a `Field` subclass.
*/
virtual Field* create(Type t, size_t n, bool dummy) const = 0;
/**
* @cond
*/
virtual ~FieldCreator() {}
/**
* @endcond
*/
};
/**
* @cond
*/
template<bool validate_only>
struct DefaultFieldCreator : public FieldCreator {
Field* create(Type observed, size_t n, bool dummy) const {
Field* ptr;
switch (observed) {
case STRING:
if (dummy || validate_only) {
ptr = new DummyStringField(n);
} else {
ptr = new FilledStringField(n);
}
break;
case NUMBER:
if (dummy || validate_only) {
ptr = new DummyNumberField(n);
} else {
ptr = new FilledNumberField(n);
}
break;
case BOOLEAN:
if (dummy || validate_only) {
ptr = new DummyBooleanField(n);
} else {
ptr = new FilledBooleanField(n);
}
break;
case COMPLEX:
if (dummy || validate_only) {
ptr = new DummyComplexField(n);
} else {
ptr = new FilledComplexField(n);
}
break;
default:
throw std::runtime_error("unrecognized type during field creation");
}
return ptr;
}
};
/**
* @endcond
*/
}
#endif
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