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//
// Copyright (c) 2022 Klemens Morgenstern (klemens.morgenstern@gmx.net)
//
// 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)
//
#ifndef BOOST_SQLITE_COLLATION_HPP
#define BOOST_SQLITE_COLLATION_HPP
#include <boost/sqlite/connection.hpp>
#include <boost/sqlite/detail/exception.hpp>
BOOST_SQLITE_BEGIN_NAMESPACE
///@{
/** Define a custom collation function
@ingroup reference
@param conn A connection to the database in which to install the collation.
@param name The name of the collation.
@param func The function
The function must be callable with two `string_view` and return an int, indicating the comparison results.
@par Example
@code{.cpp}
// a case insensitive string omparison, e.g. from boost.urls
int ci_compare(string_view s0, string_view s1) noexcept;
extern sqlite::connection conn;
// Register the collation
sqlite::create_collation(conn, "iequal", &ci_compare);
// use the collation to get by name, case insensitively
conn.query("select first_name, last_name from people where first_name = 'Klemens' collate iequal;");
// order by names case insensitively
conn.query("select * from people order by last_name collate iequal asc;");
@endcode
*/
template<typename Func>
void create_collation(
connection & conn,
cstring_ref name,
Func && func,
typename std::enable_if<
std::is_convertible<
decltype(func(string_view(), string_view())),
int>::value,
system::error_code>::type & ec)
{
using func_type = typename std::decay<Func>::type;
unique_ptr<func_type> f{new (memory_tag{}) func_type(std::forward<Func>(func))};
if (f == nullptr)
{
BOOST_SQLITE_ASSIGN_EC(ec, SQLITE_NOMEM);
return;
}
auto res = sqlite3_create_collation_v2(
conn.handle(),
name.c_str(),
SQLITE_UTF8,
f.get(),
+[](void * data, int len_l, const void * str_l, int len_r, const void * str_r) -> int
{
string_view l(static_cast<const char*>(str_l), len_l);
string_view r(static_cast<const char*>(str_r), len_r);
auto & impl = (*static_cast<func_type*>(data));
static_assert(noexcept(impl(l, r)),
"Collation function must be noexcept");
return impl(l, r);
},
+[](void * p) { delete_(static_cast<func_type*>(p)); }
);
if (res != SQLITE_OK)
BOOST_SQLITE_ASSIGN_EC(ec, res);
else
f.release();
}
template<typename Func>
auto create_collation(
connection & conn,
cstring_ref name,
Func && func)
#if !defined(BOOST_SQLITE_GENERATING_DOCS)
-> typename std::enable_if<
std::is_convertible<
decltype(func(string_view(), string_view())),
int>::value>::type
#endif
{
system::error_code ec;
create_collation(conn, name, std::forward<Func>(func), ec);
if (ec)
detail::throw_error_code(ec, BOOST_CURRENT_LOCATION);
}
inline void delete_collation(
connection & conn,
cstring_ref name,
system::error_code & ec)
{
auto res = sqlite3_create_collation_v2(
conn.handle(),
name.c_str(),
SQLITE_UTF8,
nullptr, nullptr, nullptr);
if (res != SQLITE_OK)
{
BOOST_SQLITE_ASSIGN_EC(ec, res);
}
}
inline auto delete_collation(
connection & conn,
cstring_ref name)
{
system::error_code ec;
delete_collation(conn, name, ec);
if (ec)
detail::throw_error_code(ec, BOOST_CURRENT_LOCATION);
}
/// @}
BOOST_SQLITE_END_NAMESPACE
#endif //BOOST_SQLITE_COLLATION_HPP
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