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json/develop/detail/parsing/binary_reader.hpp

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:hammer: some clean up
2018-01-10 09:18:31 +00:00
#pragma once
add detail/parsing/binary_reader.hpp
2017-08-14 15:50:24 +00:00
add missing includes, put back include comments
2017-08-14 17:28:01 +00:00
#include <algorithm> // generate_n
#include <array> // array
#include <cassert> // assert
#include <cmath> // ldexp
#include <cstddef> // size_t
#include <cstdint> // uint8_t, uint16_t, uint32_t, uint64_t
#include <cstring> // memcpy
#include <iomanip> // setw, setfill
#include <ios> // hex
#include <iterator> // back_inserter
#include <limits> // numeric_limits
#include <sstream> // stringstream
#include <string> // char_traits, string
#include <utility> // make_pair, move
add detail/parsing/binary_reader.hpp
2017-08-14 15:50:24 +00:00
#include "detail/exceptions.hpp"
#include "detail/macro_scope.hpp"
#include "detail/parsing/input_adapters.hpp"
#include "detail/value_t.hpp"
namespace nlohmann
{
namespace detail
{
///////////////////
// binary reader //
///////////////////
/*!
@brief deserialization of CBOR and MessagePack values
*/
template<typename BasicJsonType>
class binary_reader
{
using number_integer_t = typename BasicJsonType::number_integer_t;
using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
public:
/*!
@brief create a binary reader
@param[in] adapter input adapter to read from
*/
explicit binary_reader(input_adapter_t adapter) : ia(std::move(adapter))
{
assert(ia);
}
/*!
@brief create a JSON value from CBOR input
@param[in] strict whether to expect the input to be consumed completed
@return JSON value created from CBOR input
@throw parse_error.110 if input ended unexpectedly or the end of file was
not reached when @a strict was set to true
@throw parse_error.112 if unsupported byte was read
*/
BasicJsonType parse_cbor(const bool strict)
{
const auto res = parse_cbor_internal();
if (strict)
{
get();
check_eof(true);
}
return res;
}
/*!
@brief create a JSON value from MessagePack input
@param[in] strict whether to expect the input to be consumed completed
@return JSON value created from MessagePack input
@throw parse_error.110 if input ended unexpectedly or the end of file was
not reached when @a strict was set to true
@throw parse_error.112 if unsupported byte was read
*/
BasicJsonType parse_msgpack(const bool strict)
{
const auto res = parse_msgpack_internal();
if (strict)
{
get();
check_eof(true);
}
return res;
}
/*!
@brief determine system byte order
@return true if and only if system's byte order is little endian
@note from http://stackoverflow.com/a/1001328/266378
*/
static constexpr bool little_endianess(int num = 1) noexcept
{
return (*reinterpret_cast<char*>(&num) == 1);
}
private:
/*!
@param[in] get_char whether a new character should be retrieved from the
input (true, default) or whether the last read
character should be considered instead
*/
BasicJsonType parse_cbor_internal(const bool get_char = true)
{
switch (get_char ? get() : current)
{
// EOF
case std::char_traits<char>::eof():
JSON_THROW(parse_error::create(110, chars_read, "unexpected end of input"));
// Integer 0x00..0x17 (0..23)
case 0x00:
case 0x01:
case 0x02:
case 0x03:
case 0x04:
case 0x05:
case 0x06:
case 0x07:
case 0x08:
case 0x09:
case 0x0A:
case 0x0B:
case 0x0C:
case 0x0D:
case 0x0E:
case 0x0F:
case 0x10:
case 0x11:
case 0x12:
case 0x13:
case 0x14:
case 0x15:
case 0x16:
case 0x17:
return static_cast<number_unsigned_t>(current);
case 0x18: // Unsigned integer (one-byte uint8_t follows)
return get_number<uint8_t>();
case 0x19: // Unsigned integer (two-byte uint16_t follows)
return get_number<uint16_t>();
case 0x1A: // Unsigned integer (four-byte uint32_t follows)
return get_number<uint32_t>();
case 0x1B: // Unsigned integer (eight-byte uint64_t follows)
return get_number<uint64_t>();
// Negative integer -1-0x00..-1-0x17 (-1..-24)
case 0x20:
case 0x21:
case 0x22:
case 0x23:
case 0x24:
case 0x25:
case 0x26:
case 0x27:
case 0x28:
case 0x29:
case 0x2A:
case 0x2B:
case 0x2C:
case 0x2D:
case 0x2E:
case 0x2F:
case 0x30:
case 0x31:
case 0x32:
case 0x33:
case 0x34:
case 0x35:
case 0x36:
case 0x37:
return static_cast<int8_t>(0x20 - 1 - current);
case 0x38: // Negative integer (one-byte uint8_t follows)
{
// must be uint8_t !
return static_cast<number_integer_t>(-1) - get_number<uint8_t>();
}
case 0x39: // Negative integer -1-n (two-byte uint16_t follows)
{
return static_cast<number_integer_t>(-1) - get_number<uint16_t>();
}
case 0x3A: // Negative integer -1-n (four-byte uint32_t follows)
{
return static_cast<number_integer_t>(-1) - get_number<uint32_t>();
}
case 0x3B: // Negative integer -1-n (eight-byte uint64_t follows)
{
return static_cast<number_integer_t>(-1) -
static_cast<number_integer_t>(get_number<uint64_t>());
}
// UTF-8 string (0x00..0x17 bytes follow)
case 0x60:
case 0x61:
case 0x62:
case 0x63:
case 0x64:
case 0x65:
case 0x66:
case 0x67:
case 0x68:
case 0x69:
case 0x6A:
case 0x6B:
case 0x6C:
case 0x6D:
case 0x6E:
case 0x6F:
case 0x70:
case 0x71:
case 0x72:
case 0x73:
case 0x74:
case 0x75:
case 0x76:
case 0x77:
case 0x78: // UTF-8 string (one-byte uint8_t for n follows)
case 0x79: // UTF-8 string (two-byte uint16_t for n follow)
case 0x7A: // UTF-8 string (four-byte uint32_t for n follow)
case 0x7B: // UTF-8 string (eight-byte uint64_t for n follow)
case 0x7F: // UTF-8 string (indefinite length)
{
return get_cbor_string();
}
// array (0x00..0x17 data items follow)
case 0x80:
case 0x81:
case 0x82:
case 0x83:
case 0x84:
case 0x85:
case 0x86:
case 0x87:
case 0x88:
case 0x89:
case 0x8A:
case 0x8B:
case 0x8C:
case 0x8D:
case 0x8E:
case 0x8F:
case 0x90:
case 0x91:
case 0x92:
case 0x93:
case 0x94:
case 0x95:
case 0x96:
case 0x97:
{
return get_cbor_array(current & 0x1F);
}
case 0x98: // array (one-byte uint8_t for n follows)
{
return get_cbor_array(get_number<uint8_t>());
}
case 0x99: // array (two-byte uint16_t for n follow)
{
return get_cbor_array(get_number<uint16_t>());
}
case 0x9A: // array (four-byte uint32_t for n follow)
{
return get_cbor_array(get_number<uint32_t>());
}
case 0x9B: // array (eight-byte uint64_t for n follow)
{
return get_cbor_array(get_number<uint64_t>());
}
case 0x9F: // array (indefinite length)
{
BasicJsonType result = value_t::array;
while (get() != 0xFF)
{
result.push_back(parse_cbor_internal(false));
}
return result;
}
// map (0x00..0x17 pairs of data items follow)
case 0xA0:
case 0xA1:
case 0xA2:
case 0xA3:
case 0xA4:
case 0xA5:
case 0xA6:
case 0xA7:
case 0xA8:
case 0xA9:
case 0xAA:
case 0xAB:
case 0xAC:
case 0xAD:
case 0xAE:
case 0xAF:
case 0xB0:
case 0xB1:
case 0xB2:
case 0xB3:
case 0xB4:
case 0xB5:
case 0xB6:
case 0xB7:
{
return get_cbor_object(current & 0x1F);
}
case 0xB8: // map (one-byte uint8_t for n follows)
{
return get_cbor_object(get_number<uint8_t>());
}
case 0xB9: // map (two-byte uint16_t for n follow)
{
return get_cbor_object(get_number<uint16_t>());
}
case 0xBA: // map (four-byte uint32_t for n follow)
{
return get_cbor_object(get_number<uint32_t>());
}
case 0xBB: // map (eight-byte uint64_t for n follow)
{
return get_cbor_object(get_number<uint64_t>());
}
case 0xBF: // map (indefinite length)
{
BasicJsonType result = value_t::object;
while (get() != 0xFF)
{
auto key = get_cbor_string();
result[key] = parse_cbor_internal();
}
return result;
}
case 0xF4: // false
{
return false;
}
case 0xF5: // true
{
return true;
}
case 0xF6: // null
{
return value_t::null;
}
case 0xF9: // Half-Precision Float (two-byte IEEE 754)
{
const int byte1 = get();
check_eof();
const int byte2 = get();
check_eof();
// code from RFC 7049, Appendix D, Figure 3:
// As half-precision floating-point numbers were only added
// to IEEE 754 in 2008, today's programming platforms often
// still only have limited support for them. It is very
// easy to include at least decoding support for them even
// without such support. An example of a small decoder for
// half-precision floating-point numbers in the C language
// is shown in Fig. 3.
const int half = (byte1 << 8) + byte2;
const int exp = (half >> 10) & 0x1F;
const int mant = half & 0x3FF;
double val;
if (exp == 0)
{
val = std::ldexp(mant, -24);
}
else if (exp != 31)
{
val = std::ldexp(mant + 1024, exp - 25);
}
else
{
val = (mant == 0) ? std::numeric_limits<double>::infinity()
: std::numeric_limits<double>::quiet_NaN();
}
return (half & 0x8000) != 0 ? -val : val;
}
case 0xFA: // Single-Precision Float (four-byte IEEE 754)
{
return get_number<float>();
}
case 0xFB: // Double-Precision Float (eight-byte IEEE 754)
{
return get_number<double>();
}
default: // anything else (0xFF is handled inside the other types)
{
std::stringstream ss;
ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
JSON_THROW(parse_error::create(112, chars_read, "error reading CBOR; last byte: 0x" + ss.str()));
}
}
}
BasicJsonType parse_msgpack_internal()
{
switch (get())
{
// EOF
case std::char_traits<char>::eof():
JSON_THROW(parse_error::create(110, chars_read, "unexpected end of input"));
// positive fixint
case 0x00:
case 0x01:
case 0x02:
case 0x03:
case 0x04:
case 0x05:
case 0x06:
case 0x07:
case 0x08:
case 0x09:
case 0x0A:
case 0x0B:
case 0x0C:
case 0x0D:
case 0x0E:
case 0x0F:
case 0x10:
case 0x11:
case 0x12:
case 0x13:
case 0x14:
case 0x15:
case 0x16:
case 0x17:
case 0x18:
case 0x19:
case 0x1A:
case 0x1B:
case 0x1C:
case 0x1D:
case 0x1E:
case 0x1F:
case 0x20:
case 0x21:
case 0x22:
case 0x23:
case 0x24:
case 0x25:
case 0x26:
case 0x27:
case 0x28:
case 0x29:
case 0x2A:
case 0x2B:
case 0x2C:
case 0x2D:
case 0x2E:
case 0x2F:
case 0x30:
case 0x31:
case 0x32:
case 0x33:
case 0x34:
case 0x35:
case 0x36:
case 0x37:
case 0x38:
case 0x39:
case 0x3A:
case 0x3B:
case 0x3C:
case 0x3D:
case 0x3E:
case 0x3F:
case 0x40:
case 0x41:
case 0x42:
case 0x43:
case 0x44:
case 0x45:
case 0x46:
case 0x47:
case 0x48:
case 0x49:
case 0x4A:
case 0x4B:
case 0x4C:
case 0x4D:
case 0x4E:
case 0x4F:
case 0x50:
case 0x51:
case 0x52:
case 0x53:
case 0x54:
case 0x55:
case 0x56:
case 0x57:
case 0x58:
case 0x59:
case 0x5A:
case 0x5B:
case 0x5C:
case 0x5D:
case 0x5E:
case 0x5F:
case 0x60:
case 0x61:
case 0x62:
case 0x63:
case 0x64:
case 0x65:
case 0x66:
case 0x67:
case 0x68:
case 0x69:
case 0x6A:
case 0x6B:
case 0x6C:
case 0x6D:
case 0x6E:
case 0x6F:
case 0x70:
case 0x71:
case 0x72:
case 0x73:
case 0x74:
case 0x75:
case 0x76:
case 0x77:
case 0x78:
case 0x79:
case 0x7A:
case 0x7B:
case 0x7C:
case 0x7D:
case 0x7E:
case 0x7F:
return static_cast<number_unsigned_t>(current);
// fixmap
case 0x80:
case 0x81:
case 0x82:
case 0x83:
case 0x84:
case 0x85:
case 0x86:
case 0x87:
case 0x88:
case 0x89:
case 0x8A:
case 0x8B:
case 0x8C:
case 0x8D:
case 0x8E:
case 0x8F:
{
return get_msgpack_object(current & 0x0F);
}
// fixarray
case 0x90:
case 0x91:
case 0x92:
case 0x93:
case 0x94:
case 0x95:
case 0x96:
case 0x97:
case 0x98:
case 0x99:
case 0x9A:
case 0x9B:
case 0x9C:
case 0x9D:
case 0x9E:
case 0x9F:
{
return get_msgpack_array(current & 0x0F);
}
// fixstr
case 0xA0:
case 0xA1:
case 0xA2:
case 0xA3:
case 0xA4:
case 0xA5:
case 0xA6:
case 0xA7:
case 0xA8:
case 0xA9:
case 0xAA:
case 0xAB:
case 0xAC:
case 0xAD:
case 0xAE:
case 0xAF:
case 0xB0:
case 0xB1:
case 0xB2:
case 0xB3:
case 0xB4:
case 0xB5:
case 0xB6:
case 0xB7:
case 0xB8:
case 0xB9:
case 0xBA:
case 0xBB:
case 0xBC:
case 0xBD:
case 0xBE:
case 0xBF:
return get_msgpack_string();
case 0xC0: // nil
return value_t::null;
case 0xC2: // false
return false;
case 0xC3: // true
return true;
case 0xCA: // float 32
return get_number<float>();
case 0xCB: // float 64
return get_number<double>();
case 0xCC: // uint 8
return get_number<uint8_t>();
case 0xCD: // uint 16
return get_number<uint16_t>();
case 0xCE: // uint 32
return get_number<uint32_t>();
case 0xCF: // uint 64
return get_number<uint64_t>();
case 0xD0: // int 8
return get_number<int8_t>();
case 0xD1: // int 16
return get_number<int16_t>();
case 0xD2: // int 32
return get_number<int32_t>();
case 0xD3: // int 64
return get_number<int64_t>();
case 0xD9: // str 8
case 0xDA: // str 16
case 0xDB: // str 32
return get_msgpack_string();
case 0xDC: // array 16
{
return get_msgpack_array(get_number<uint16_t>());
}
case 0xDD: // array 32
{
return get_msgpack_array(get_number<uint32_t>());
}
case 0xDE: // map 16
{
return get_msgpack_object(get_number<uint16_t>());
}
case 0xDF: // map 32
{
return get_msgpack_object(get_number<uint32_t>());
}
// positive fixint
case 0xE0:
case 0xE1:
case 0xE2:
case 0xE3:
case 0xE4:
case 0xE5:
case 0xE6:
case 0xE7:
case 0xE8:
case 0xE9:
case 0xEA:
case 0xEB:
case 0xEC:
case 0xED:
case 0xEE:
case 0xEF:
case 0xF0:
case 0xF1:
case 0xF2:
case 0xF3:
case 0xF4:
case 0xF5:
case 0xF6:
case 0xF7:
case 0xF8:
case 0xF9:
case 0xFA:
case 0xFB:
case 0xFC:
case 0xFD:
case 0xFE:
case 0xFF:
return static_cast<int8_t>(current);
default: // anything else
{
std::stringstream ss;
ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
JSON_THROW(parse_error::create(112, chars_read,
"error reading MessagePack; last byte: 0x" + ss.str()));
}
}
}
/*!
@brief get next character from the input
This function provides the interface to the used input adapter. It does
not throw in case the input reached EOF, but returns a -'ve valued
`std::char_traits<char>::eof()` in that case.
@return character read from the input
*/
int get()
{
++chars_read;
return (current = ia->get_character());
}
/*
@brief read a number from the input
@tparam NumberType the type of the number
@return number of type @a NumberType
@note This function needs to respect the system's endianess, because
bytes in CBOR and MessagePack are stored in network order (big
endian) and therefore need reordering on little endian systems.
@throw parse_error.110 if input has less than `sizeof(NumberType)` bytes
*/
template<typename NumberType> NumberType get_number()
{
// step 1: read input into array with system's byte order
std::array<uint8_t, sizeof(NumberType)> vec;
for (std::size_t i = 0; i < sizeof(NumberType); ++i)
{
get();
check_eof();
// reverse byte order prior to conversion if necessary
if (is_little_endian)
{
vec[sizeof(NumberType) - i - 1] = static_cast<uint8_t>(current);
}
else
{
vec[i] = static_cast<uint8_t>(current); // LCOV_EXCL_LINE
}
}
// step 2: convert array into number of type T and return
NumberType result;
std::memcpy(&result, vec.data(), sizeof(NumberType));
return result;
}
/*!
@brief create a string by reading characters from the input
@param[in] len number of bytes to read
@note We can not reserve @a len bytes for the result, because @a len
may be too large. Usually, @ref check_eof() detects the end of
the input before we run out of string memory.
@return string created by reading @a len bytes
@throw parse_error.110 if input has less than @a len bytes
*/
template<typename NumberType>
std::string get_string(const NumberType len)
{
std::string result;
std::generate_n(std::back_inserter(result), len, [this]()
{
get();
check_eof();
return static_cast<char>(current);
});
return result;
}
/*!
@brief reads a CBOR string
This function first reads starting bytes to determine the expected
string length and then copies this number of bytes into a string.
Additionally, CBOR's strings with indefinite lengths are supported.
@return string
@throw parse_error.110 if input ended
@throw parse_error.113 if an unexpected byte is read
*/
std::string get_cbor_string()
{
check_eof();
switch (current)
{
// UTF-8 string (0x00..0x17 bytes follow)
case 0x60:
case 0x61:
case 0x62:
case 0x63:
case 0x64:
case 0x65:
case 0x66:
case 0x67:
case 0x68:
case 0x69:
case 0x6A:
case 0x6B:
case 0x6C:
case 0x6D:
case 0x6E:
case 0x6F:
case 0x70:
case 0x71:
case 0x72:
case 0x73:
case 0x74:
case 0x75:
case 0x76:
case 0x77:
{
return get_string(current & 0x1F);
}
case 0x78: // UTF-8 string (one-byte uint8_t for n follows)
{
return get_string(get_number<uint8_t>());
}
case 0x79: // UTF-8 string (two-byte uint16_t for n follow)
{
return get_string(get_number<uint16_t>());
}
case 0x7A: // UTF-8 string (four-byte uint32_t for n follow)
{
return get_string(get_number<uint32_t>());
}
case 0x7B: // UTF-8 string (eight-byte uint64_t for n follow)
{
return get_string(get_number<uint64_t>());
}
case 0x7F: // UTF-8 string (indefinite length)
{
std::string result;
while (get() != 0xFF)
{
check_eof();
result.push_back(static_cast<char>(current));
}
return result;
}
default:
{
std::stringstream ss;
ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
JSON_THROW(parse_error::create(113, chars_read, "expected a CBOR string; last byte: 0x" + ss.str()));
}
}
}
template<typename NumberType>
BasicJsonType get_cbor_array(const NumberType len)
{
BasicJsonType result = value_t::array;
std::generate_n(std::back_inserter(*result.m_value.array), len, [this]()
{
return parse_cbor_internal();
});
return result;
}
template<typename NumberType>
BasicJsonType get_cbor_object(const NumberType len)
{
BasicJsonType result = value_t::object;
std::generate_n(std::inserter(*result.m_value.object,
result.m_value.object->end()),
len, [this]()
{
get();
auto key = get_cbor_string();
auto val = parse_cbor_internal();
return std::make_pair(std::move(key), std::move(val));
});
return result;
}
/*!
@brief reads a MessagePack string
This function first reads starting bytes to determine the expected
string length and then copies this number of bytes into a string.
@return string
@throw parse_error.110 if input ended
@throw parse_error.113 if an unexpected byte is read
*/
std::string get_msgpack_string()
{
check_eof();
switch (current)
{
// fixstr
case 0xA0:
case 0xA1:
case 0xA2:
case 0xA3:
case 0xA4:
case 0xA5:
case 0xA6:
case 0xA7:
case 0xA8:
case 0xA9:
case 0xAA:
case 0xAB:
case 0xAC:
case 0xAD:
case 0xAE:
case 0xAF:
case 0xB0:
case 0xB1:
case 0xB2:
case 0xB3:
case 0xB4:
case 0xB5:
case 0xB6:
case 0xB7:
case 0xB8:
case 0xB9:
case 0xBA:
case 0xBB:
case 0xBC:
case 0xBD:
case 0xBE:
case 0xBF:
{
return get_string(current & 0x1F);
}
case 0xD9: // str 8
{
return get_string(get_number<uint8_t>());
}
case 0xDA: // str 16
{
return get_string(get_number<uint16_t>());
}
case 0xDB: // str 32
{
return get_string(get_number<uint32_t>());
}
default:
{
std::stringstream ss;
ss << std::setw(2) << std::uppercase << std::setfill('0') << std::hex << current;
JSON_THROW(parse_error::create(113, chars_read,
"expected a MessagePack string; last byte: 0x" + ss.str()));
}
}
}
template<typename NumberType>
BasicJsonType get_msgpack_array(const NumberType len)
{
BasicJsonType result = value_t::array;
std::generate_n(std::back_inserter(*result.m_value.array), len, [this]()
{
return parse_msgpack_internal();
});
return result;
}
template<typename NumberType>
BasicJsonType get_msgpack_object(const NumberType len)
{
BasicJsonType result = value_t::object;
std::generate_n(std::inserter(*result.m_value.object,
result.m_value.object->end()),
len, [this]()
{
get();
auto key = get_msgpack_string();
auto val = parse_msgpack_internal();
return std::make_pair(std::move(key), std::move(val));
});
return result;
}
/*!
@brief check if input ended
@throw parse_error.110 if input ended
*/
void check_eof(const bool expect_eof = false) const
{
if (expect_eof)
{
if (JSON_UNLIKELY(current != std::char_traits<char>::eof()))
{
JSON_THROW(parse_error::create(110, chars_read, "expected end of input"));
}
}
else
{
if (JSON_UNLIKELY(current == std::char_traits<char>::eof()))
{
JSON_THROW(parse_error::create(110, chars_read, "unexpected end of input"));
}
}
}
private:
/// input adapter
input_adapter_t ia = nullptr;
/// the current character
int current = std::char_traits<char>::eof();
/// the number of characters read
std::size_t chars_read = 0;
/// whether we can assume little endianess
const bool is_little_endian = little_endianess();
};
}
}
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