H5ReadWrite_misc.hpp

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/*
 *  Copyright (c) 2020 Blue Brain Project
 *
 *  Distributed under the Boost Software License, Version 1.0.
 *    (See accompanying file LICENSE_1_0.txt or copy at
 *          http://www.boost.org/LICENSE_1_0.txt)
 *
 */
#pragma once
 
#include "H5Utils.hpp"
 
namespace HighFive {
 
namespace details {
 
template <typename T>
struct BufferInfo {
    using type_no_const = typename std::remove_const<T>::type;
    using elem_type = typename details::type_of_array<type_no_const>::type;
    using char_array_t = typename details::type_char_array<type_no_const>::type;
    static constexpr bool is_char_array = ! std::is_same<char_array_t, void>::value;
 
    BufferInfo(const DataType& dtype);
 
    // member data for info depending on the destination dataset type
    const bool is_fixed_len_string;
    const size_t n_dimensions;
    const DataType data_type;
};
 
// details implementation
template <typename SrcStrT>
struct string_type_checker {
    static DataType getDataType(const DataType&, bool);
};
 
template <>
struct string_type_checker<void> {
inline static DataType getDataType(const DataType& element_type, bool) {
    return element_type;
}};
 
template <std::size_t FixedLen>
struct string_type_checker<char[FixedLen]> {
inline static DataType getDataType(const DataType& element_type, bool ds_fixed_str) {
    return ds_fixed_str ? AtomicType<char[FixedLen]>() : element_type;
}};
 
template <>
struct string_type_checker<char*> {
inline static DataType getDataType(const DataType&, bool ds_fixed_str) {
    if (ds_fixed_str)
        throw DataSetException("Can't output variable-length to fixed-length strings");
    return AtomicType<std::string>();
}};
 
template <typename T>
BufferInfo<T>::BufferInfo(const DataType& dtype)
    : is_fixed_len_string(dtype.isFixedLenStr())
    // In case we are using Fixed-len strings we need to subtract one dimension
    , n_dimensions(details::array_dims<type_no_const>::value -
                   ((is_fixed_len_string && is_char_array) ? 1 : 0))
    , data_type(string_type_checker<char_array_t>::getDataType(
            create_datatype<elem_type>(), is_fixed_len_string)) {
    if (is_fixed_len_string && std::is_same<elem_type, std::string>::value) {
        throw DataSetException("Can't output std::string as fixed-length. "
                               "Use raw arrays or FixedLenStringArray");
    }
    // We warn. In case they are really not convertible an exception will rise on read/write
    if (dtype.getClass() != data_type.getClass()) {
        std::cerr << "HighFive WARNING: data and hdf5 dataset have different types: "
                  << data_type.string() << " -> " << dtype.string() << std::endl;
    }
}
 
}  // namespace details
 
}  // namespace HighFive