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🎨 clean up binary formats

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This commit is contained in:
Niels Lohmann 2018-10-24 23:39:30 +02:00
parent 4d1eaace8c
commit 1968e5c793
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GPG key ID: 7F3CEA63AE251B69
5 changed files with 1274 additions and 1122 deletions
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312
include/nlohmann/detail/output/binary_writer.hpp
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@ -35,7 +35,34 @@ class binary_writer
}
/*!
@brief[in] j JSON value to serialize
@param[in] j JSON value to serialize
@pre j.type() == value_t::object
*/
void write_bson(const BasicJsonType& j)
{
switch (j.type())
{
case value_t::object:
{
write_bson_object(*j.m_value.object);
break;
}
case value_t::discarded:
{
break;
}
default:
{
JSON_THROW(type_error::create(317, "to serialize to BSON, top-level type must be object, but is " + std::string(j.type_name())));
break;
}
}
}
/*!
@param[in] j JSON value to serialize
*/
void write_cbor(const BasicJsonType& j)
{
@ -279,7 +306,7 @@ class binary_writer
}
/*!
@brief[in] j JSON value to serialize
@param[in] j JSON value to serialize
*/
void write_msgpack(const BasicJsonType& j)
{
@ -678,13 +705,19 @@ class binary_writer
}
}
private:
//////////
// BSON //
//////////
/*!
@return The size of a BSON document entry header, including the id marker and the entry name size (and its null-terminator).
@return The size of a BSON document entry header, including the id marker
and the entry name size (and its null-terminator).
*/
static std::size_t calc_bson_entry_header_size(const typename BasicJsonType::string_t& name)
{
const auto it = name.find(static_cast<typename BasicJsonType::string_t::value_type>(0));
if (it != BasicJsonType::string_t::npos)
if (JSON_UNLIKELY(it != BasicJsonType::string_t::npos))
{
JSON_THROW(out_of_range::create(409,
"BSON key cannot contain code point U+0000 (at byte " + std::to_string(it) + ")"));
@ -696,7 +729,8 @@ class binary_writer
/*!
@brief Writes the given @a element_type and @a name to the output adapter
*/
void write_bson_entry_header(const typename BasicJsonType::string_t& name, std::uint8_t element_type)
void write_bson_entry_header(const typename BasicJsonType::string_t& name,
std::uint8_t element_type)
{
oa->write_character(static_cast<CharType>(element_type)); // boolean
oa->write_characters(
@ -707,7 +741,8 @@ class binary_writer
/*!
@brief Writes a BSON element with key @a name and boolean value @a value
*/
void write_bson_boolean(const typename BasicJsonType::string_t& name, const bool value)
void write_bson_boolean(const typename BasicJsonType::string_t& name,
const bool value)
{
write_bson_entry_header(name, 0x08);
oa->write_character(value ? static_cast<CharType>(0x01) : static_cast<CharType>(0x00));
@ -716,7 +751,8 @@ class binary_writer
/*!
@brief Writes a BSON element with key @a name and double value @a value
*/
void write_bson_double(const typename BasicJsonType::string_t& name, const double value)
void write_bson_double(const typename BasicJsonType::string_t& name,
const double value)
{
write_bson_entry_header(name, 0x01);
write_number<double, true>(value);
@ -733,7 +769,8 @@ class binary_writer
/*!
@brief Writes a BSON element with key @a name and string value @a value
*/
void write_bson_string(const typename BasicJsonType::string_t& name, const typename BasicJsonType::string_t& value)
void write_bson_string(const typename BasicJsonType::string_t& name,
const typename BasicJsonType::string_t& value)
{
write_bson_entry_header(name, 0x02);
@ -769,7 +806,8 @@ class binary_writer
/*!
@brief Writes a BSON element with key @a name and integer @a value
*/
void write_bson_integer(const typename BasicJsonType::string_t& name, const std::int64_t value)
void write_bson_integer(const typename BasicJsonType::string_t& name,
const std::int64_t value)
{
if ((std::numeric_limits<std::int32_t>::min)() <= value and value <= (std::numeric_limits<std::int32_t>::max)())
{
@ -783,7 +821,6 @@ class binary_writer
}
}
/*!
@return The size of the BSON-encoded unsigned integer in @a j
*/
@ -802,7 +839,8 @@ class binary_writer
/*!
@brief Writes a BSON element with key @a name and unsigned @a value
*/
void write_bson_unsigned(const typename BasicJsonType::string_t& name, const std::uint64_t value)
void write_bson_unsigned(const typename BasicJsonType::string_t& name,
const std::uint64_t value)
{
if (value <= static_cast<std::uint64_t>((std::numeric_limits<std::int32_t>::max)()))
{
@ -824,13 +862,13 @@ class binary_writer
/*!
@brief Writes a BSON element with key @a name and object @a value
*/
void write_bson_object_entry(const typename BasicJsonType::string_t& name, const typename BasicJsonType::object_t& value)
void write_bson_object_entry(const typename BasicJsonType::string_t& name,
const typename BasicJsonType::object_t& value)
{
write_bson_entry_header(name, 0x03); // object
write_bson_object(value);
}
/*!
@return The size of the BSON-encoded array @a value
*/
@ -849,10 +887,11 @@ class binary_writer
/*!
@brief Writes a BSON element with key @a name and array @a value
*/
void write_bson_array(const typename BasicJsonType::string_t& name, const typename BasicJsonType::array_t& value)
void write_bson_array(const typename BasicJsonType::string_t& name,
const typename BasicJsonType::array_t& value)
{
write_bson_entry_header(name, 0x04); // array
write_number<std::int32_t, true>(calc_bson_array_size(value));
write_number<std::int32_t, true>(static_cast<std::int32_t>(calc_bson_array_size(value)));
for (const auto& el : value)
{
@ -862,75 +901,95 @@ class binary_writer
oa->write_character(static_cast<CharType>(0x00));
}
/*!
@brief Calculates the size necessary to serialize the JSON value @a j with its @a name
@return The calculated size for the BSON document entry for @a j with the given @a name.
*/
static std::size_t calc_bson_element_size(const typename BasicJsonType::string_t& name, const BasicJsonType& j)
static std::size_t calc_bson_element_size(const typename BasicJsonType::string_t& name,
const BasicJsonType& j)
{
const auto header_size = calc_bson_entry_header_size(name);
switch (j.type())
{
case value_t::discarded:
return 0ul;
case value_t::object:
return header_size + calc_bson_object_size(*j.m_value.object);
case value_t::array:
return header_size + calc_bson_array_size(*j.m_value.array);
case value_t::boolean:
return header_size + 1ul;
case value_t::number_float:
return header_size + 8ul;
case value_t::number_integer:
return header_size + calc_bson_integer_size(j.m_value.number_integer);
case value_t::number_unsigned:
return header_size + calc_bson_unsigned_size(j.m_value.number_unsigned);
case value_t::string:
return header_size + calc_bson_string_size(*j.m_value.string);
case value_t::null:
return header_size + 0ul;
// LCOV_EXCL_START
default:
assert(false);
return 0ul;
// LCOV_EXCL_STOP
case value_t::discarded:
return 0ul;
case value_t::object:
return header_size + calc_bson_object_size(*j.m_value.object);
case value_t::array:
return header_size + calc_bson_array_size(*j.m_value.array);
case value_t::boolean:
return header_size + 1ul;
case value_t::number_float:
return header_size + 8ul;
case value_t::number_integer:
return header_size + calc_bson_integer_size(j.m_value.number_integer);
case value_t::number_unsigned:
return header_size + calc_bson_unsigned_size(j.m_value.number_unsigned);
case value_t::string:
return header_size + calc_bson_string_size(*j.m_value.string);
case value_t::null:
return header_size + 0ul;
// LCOV_EXCL_STOP
};
}
/*!
@brief Serializes the JSON value @a j to BSON and associates it with the key @a name.
@param name The name to associate with the JSON entity @a j within the current BSON document
@return The size of the bson entry
@brief Serializes the JSON value @a j to BSON and associates it with the
key @a name.
@param name The name to associate with the JSON entity @a j within the
current BSON document
@return The size of the BSON entry
*/
void write_bson_element(const typename BasicJsonType::string_t& name, const BasicJsonType& j)
void write_bson_element(const typename BasicJsonType::string_t& name,
const BasicJsonType& j)
{
switch (j.type())
{
case value_t::discarded:
return;
case value_t::object:
return write_bson_object_entry(name, *j.m_value.object);
case value_t::array:
return write_bson_array(name, *j.m_value.array);
case value_t::boolean:
return write_bson_boolean(name, j.m_value.boolean);
case value_t::number_float:
return write_bson_double(name, j.m_value.number_float);
case value_t::number_integer:
return write_bson_integer(name, j.m_value.number_integer);
case value_t::number_unsigned:
return write_bson_unsigned(name, j.m_value.number_unsigned);
case value_t::string:
return write_bson_string(name, *j.m_value.string);
case value_t::null:
return write_bson_null(name);
// LCOV_EXCL_START
default:
assert(false);
return;
// LCOV_EXCL_STOP
case value_t::discarded:
return;
case value_t::object:
return write_bson_object_entry(name, *j.m_value.object);
case value_t::array:
return write_bson_array(name, *j.m_value.array);
case value_t::boolean:
return write_bson_boolean(name, j.m_value.boolean);
case value_t::number_float:
return write_bson_double(name, j.m_value.number_float);
case value_t::number_integer:
return write_bson_integer(name, j.m_value.number_integer);
case value_t::number_unsigned:
return write_bson_unsigned(name, j.m_value.number_unsigned);
case value_t::string:
return write_bson_string(name, *j.m_value.string);
case value_t::null:
return write_bson_null(name);
// LCOV_EXCL_STOP
};
}
@ -958,7 +1017,7 @@ class binary_writer
*/
void write_bson_object(const typename BasicJsonType::object_t& value)
{
write_number<std::int32_t, true>(calc_bson_object_size(value));
write_number<std::int32_t, true>(static_cast<std::int32_t>(calc_bson_object_size(value)));
for (const auto& el : value)
{
@ -968,64 +1027,38 @@ class binary_writer
oa->write_character(static_cast<CharType>(0x00));
}
/*!
@param[in] j JSON value to serialize
@pre j.type() == value_t::object
*/
void write_bson(const BasicJsonType& j)
//////////
// CBOR //
//////////
static constexpr CharType get_cbor_float_prefix(float /*unused*/)
{
switch (j.type())
{
case value_t::object:
{
write_bson_object(*j.m_value.object);
break;
}
case value_t::discarded:
{
break;
}
default:
{
JSON_THROW(type_error::create(317, "to serialize to BSON, top-level type must be object, but is " + std::string(j.type_name())));
break;
}
}
return static_cast<CharType>(0xFA); // Single-Precision Float
}
private:
/*
@brief write a number to output input
@param[in] n number of type @a NumberType
@tparam NumberType the type of the number
@tparam OutputIsLittleEndian Set to true if output data is
required to be little endian
@note This function needs to respect the system's endianess, because bytes
in CBOR, MessagePack, and UBJSON are stored in network order (big
endian) and therefore need reordering on little endian systems.
*/
template<typename NumberType, bool OutputIsLittleEndian = false>
void write_number(const NumberType n)
static constexpr CharType get_cbor_float_prefix(double /*unused*/)
{
// step 1: write number to array of length NumberType
std::array<CharType, sizeof(NumberType)> vec;
std::memcpy(vec.data(), &n, sizeof(NumberType));
// step 2: write array to output (with possible reordering)
if (is_little_endian and not OutputIsLittleEndian)
{
// reverse byte order prior to conversion if necessary
std::reverse(vec.begin(), vec.end());
}
oa->write_characters(vec.data(), sizeof(NumberType));
return static_cast<CharType>(0xFB); // Double-Precision Float
}
/////////////
// MsgPack //
/////////////
static constexpr CharType get_msgpack_float_prefix(float /*unused*/)
{
return static_cast<CharType>(0xCA); // float 32
}
static constexpr CharType get_msgpack_float_prefix(double /*unused*/)
{
return static_cast<CharType>(0xCB); // float 64
}
////////////
// UBJSON //
////////////
// UBJSON: write number (floating point)
template<typename NumberType, typename std::enable_if<
std::is_floating_point<NumberType>::value, int>::type = 0>
@ -1226,26 +1259,6 @@ class binary_writer
}
}
static constexpr CharType get_cbor_float_prefix(float /*unused*/)
{
return static_cast<CharType>(0xFA); // Single-Precision Float
}
static constexpr CharType get_cbor_float_prefix(double /*unused*/)
{
return static_cast<CharType>(0xFB); // Double-Precision Float
}
static constexpr CharType get_msgpack_float_prefix(float /*unused*/)
{
return static_cast<CharType>(0xCA); // float 32
}
static constexpr CharType get_msgpack_float_prefix(double /*unused*/)
{
return static_cast<CharType>(0xCB); // float 64
}
static constexpr CharType get_ubjson_float_prefix(float /*unused*/)
{
return 'd'; // float 32
@ -1256,6 +1269,39 @@ class binary_writer
return 'D'; // float 64
}
///////////////////////
// Utility functions //
///////////////////////
/*
@brief write a number to output input
@param[in] n number of type @a NumberType
@tparam NumberType the type of the number
@tparam OutputIsLittleEndian Set to true if output data is
required to be little endian
@note This function needs to respect the system's endianess, because bytes
in CBOR, MessagePack, and UBJSON are stored in network order (big
endian) and therefore need reordering on little endian systems.
*/
template<typename NumberType, bool OutputIsLittleEndian = false>
void write_number(const NumberType n)
{
// step 1: write number to array of length NumberType
std::array<CharType, sizeof(NumberType)> vec;
std::memcpy(vec.data(), &n, sizeof(NumberType));
// step 2: write array to output (with possible reordering)
if (is_little_endian and not OutputIsLittleEndian)
{
// reverse byte order prior to conversion if necessary
std::reverse(vec.begin(), vec.end());
}
oa->write_characters(vec.data(), sizeof(NumberType));
}
private:
/// whether we can assume little endianess
const bool is_little_endian = binary_reader<BasicJsonType>::little_endianess();