mirror of
https://github.com/nlohmann/json.git
synced 2026-10-01 06:25:17 +00:00
34f1bff147
The public classes of the zero-copy view (#5295), in the new header <nlohmann/json_view.hpp>: - basic_json_document<BasicJsonType>: parse (borrowing contiguous byte inputs, owning rvalue strings, streams, and other inputs), parse_copy, accept, read, root, is_discarded, source, owns_source, node_count, memory_usage, shrink_to_fit - basic_json_view<BasicJsonType>: type and the is_* queries, size, empty, materialize (the value parse() would produce, built by the same SAX handler), source_offset - the aliases json_document, json_view, ordered_json_document, and ordered_json_view A parse error throws the exception basic_json::parse would throw for the same input: the library parser is run on the failing input, so messages, positions, and exception ids are the same. Inputs of 4 GiB or more are rejected with out_of_range.416. The single header single_include/nlohmann/json_view.hpp keeps including json.hpp; make amalgamate, check-amalgamation, include.zip, and release handle it. Signed-off-by: Niels Lohmann <mail@nlohmann.me>
87 lines
2.8 KiB
C++
87 lines
2.8 KiB
C++
// __ _____ _____ _____
|
|
// __| | __| | | | JSON for Modern C++
|
|
// | | |__ | | | | | | version 3.12.0
|
|
// |_____|_____|_____|_|___| https://github.com/nlohmann/json
|
|
//
|
|
// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
|
|
// SPDX-License-Identifier: MIT
|
|
|
|
#pragma once
|
|
|
|
#include <string> // basic_string, char_traits, string
|
|
#include <type_traits> // decay, integral_constant, is_array, is_lvalue_reference, is_pointer, is_same, remove_reference
|
|
#include <utility> // forward
|
|
|
|
#include <nlohmann/json.hpp>
|
|
#include <nlohmann/detail/view/macro_scope.hpp>
|
|
|
|
#if NLOHMANN_VIEW_HAS_CPP_17
|
|
#include <string_view> // string_view
|
|
#endif
|
|
|
|
NLOHMANN_JSON_NAMESPACE_BEGIN
|
|
namespace detail
|
|
{
|
|
namespace view
|
|
{
|
|
|
|
/// how a document takes its input
|
|
enum class input_kind
|
|
{
|
|
move_string, ///< rvalue std::string: owned without a copy
|
|
c_string, ///< const char* (NUL-terminated): borrowed
|
|
char_array, ///< char array (e.g. a string literal): borrowed
|
|
borrow_range, ///< lvalue contiguous byte container, or std::string_view: borrowed
|
|
copy_range, ///< rvalue contiguous byte container: copied
|
|
adapter, ///< anything else parse() accepts (streams, wide strings, ...): read into a buffer
|
|
};
|
|
|
|
template<typename InputType>
|
|
struct classify_input
|
|
{
|
|
using R = typename std::remove_reference<InputType>::type;
|
|
using D = typename std::decay<InputType>::type;
|
|
static constexpr bool is_rvalue = !std::is_lvalue_reference<InputType>::value;
|
|
static constexpr bool is_bytes = is_contiguous_byte_container<D>::value;
|
|
#if NLOHMANN_VIEW_HAS_CPP_17
|
|
static constexpr bool is_string_view = std::is_same<D, std::string_view>::value;
|
|
#else
|
|
static constexpr bool is_string_view = false;
|
|
#endif
|
|
static constexpr input_kind value =
|
|
std::is_array<R>::value ? input_kind::char_array
|
|
: std::is_pointer<D>::value ? input_kind::c_string
|
|
: (is_rvalue && std::is_same<D, std::string>::value) ? input_kind::move_string
|
|
: (is_bytes && (!is_rvalue || is_string_view)) ? input_kind::borrow_range
|
|
: is_bytes ? input_kind::copy_range
|
|
: input_kind::adapter;
|
|
};
|
|
|
|
/// std::basic_string guarantees a NUL at data()[size()] (the parser's sentinel)
|
|
template<typename T>
|
|
struct is_std_string : std::false_type {};
|
|
|
|
template<typename Traits, typename Alloc>
|
|
struct is_std_string<std::basic_string<char, Traits, Alloc>> : std::true_type {};
|
|
|
|
/// drain a json input adapter (UTF-16/32 inputs arrive as UTF-8)
|
|
template<typename Adapter>
|
|
std::string collect_adapter(Adapter&& ia)
|
|
{
|
|
std::string buf;
|
|
for (;;)
|
|
{
|
|
const auto ch = ia.get_character();
|
|
if (ch == std::char_traits<char>::eof())
|
|
{
|
|
break;
|
|
}
|
|
buf.push_back(static_cast<char>(ch));
|
|
}
|
|
return buf;
|
|
}
|
|
|
|
} // namespace view
|
|
} // namespace detail
|
|
NLOHMANN_JSON_NAMESPACE_END
|