join_split.h

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#ifndef GUL14_JOIN_SPLIT_H_
#define GUL14_JOIN_SPLIT_H_
 
#include <iterator>
#include <regex>
#include <string>
#include <type_traits>
#include <vector>
#include "gul14/internal.h"
#include "gul14/string_util.h"
#include "gul14/string_view.h"
 
namespace gul14 {
 
template <typename StringContainer = std::vector<std::string>,
          typename ContainerInsertFct = void (*)(StringContainer&, string_view)>
inline StringContainer
split(string_view text, string_view delimiter,
      ContainerInsertFct insert_fct = detail::emplace_back<StringContainer>)
{
    using StringType = typename StringContainer::value_type;
    using SizeType = typename StringType::size_type;
 
    auto result = StringContainer{ };
    auto search_start = SizeType{ 0 };
    auto push_start = search_start;
 
    for (;;) {
        const auto hit = text.find(delimiter.data(), search_start, delimiter.size());
        if (hit == StringType::npos)
            break;
        const auto hit_len = hit - push_start;
        insert_fct(result, text.substr(push_start, hit_len));
        search_start += std::max(delimiter.size() + hit_len, SizeType{ 1 });
        push_start += delimiter.size() + hit_len;
    }
    insert_fct(result, text.substr(push_start));
    return result;
}
 
template <typename StringContainer = std::vector<std::string>,
          typename ContainerInsertFct = void (*)(StringContainer&, string_view)>
inline StringContainer
split(string_view text, const std::regex& delimiter,
      ContainerInsertFct insert_fct = detail::emplace_back<StringContainer>)
{
    auto const end = std::cregex_iterator{ };
    auto result = StringContainer{ };
 
    auto parts = std::cregex_iterator(text.begin(), text.end(), delimiter);
    if (parts == end)
    {
        insert_fct(result, text);
    }
    else
    {
        auto previous = std::cregex_iterator{ };
        for (; parts != end; ++parts) {
            if (parts == previous and not parts->length())
                break;
            auto const& match = parts->prefix();
            insert_fct(result, string_view(match.first, match.length()));
            previous = parts;
        }
 
        auto const& match = previous->suffix();
        insert_fct(result, string_view(match.first, match.length()));
    }
 
    return result;
}
 
template <typename StringContainer = std::vector<string_view>,
          typename ContainerInsertFct = void (*)(StringContainer&, string_view)>
inline StringContainer
split_sv(string_view text, string_view delimiter,
      ContainerInsertFct insert_fct = detail::emplace_back<StringContainer>)
{
    return split<StringContainer>(text, delimiter, insert_fct);
}
 
template <typename StringContainer>
inline std::string
join(const StringContainer& parts, string_view glue)
{
    return join(parts.begin(), parts.end(), glue);
}
 
template <typename Iterator>
inline std::string
join(Iterator begin, Iterator end, string_view glue)
{
    std::string result;
 
    if (begin == end)
        return result; // Return an empty string
 
    std::size_t num_strings = 0;
    std::size_t len = 0;
 
    for (auto it = begin; it != end; ++it)
    {
        ++num_strings;
        len += it->size();
    }
    len += (num_strings - 1) * glue.size();
 
    result.reserve(len);
 
    result += *begin;
 
    // Iterate over all but the last string
    for (auto it = std::next(begin); it != end; ++it)
    {
        result.append(glue.data(), glue.size());
        result += *it;
    }
 
    return result;
}
 
 
} // namespace gul14
 
#endif
 
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