Add BON8 support (#2998)

* Add BON8 support

Add to_bon8/from_bon8 and input_format_t::bon8 for BON8, a binary format
that uses the byte values that cannot begin a UTF-8 character as type
markers, so strings need no length prefix. It is the most compact of the
supported binary formats on the benchmark files.

The reader is non-recursive like the other binary readers. A string ends
at the first byte that cannot continue it, so the reader hands the one or
two bytes it reads past a string back to the value that follows. The
writer produces the canonical representation of the specification, except
for NFC normalization; its output is identical to that of the reference
implementation (HikoGUI) on all files of the test data.

The round-trip tests need the .bon8 files of json_test_data 3.2.0.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address review comments

- Reuse detail::validate_one_utf8 to check strings in to_bon8; the error
  now names the first byte of the invalid sequence.
- Document that to_bon8 leaves bytes in the output adapter on an
  exception, and that string_open is only an output of write_bon8_marker.
- Explain why the pushback buffer of the BON8 reader cannot overflow.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Select the BON8 float prefix by type

get_bon8_float_prefix only depends on the type of its argument, so make
the type a template parameter instead of passing an unused value.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Rename a test variable that Flawfinder mistakes for read()

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix the BON8 CI failures

- compare the float in write_bon8_float with number_float_t constants,
  so GCC does not warn about a float-to-double conversion
- mark check_bon8_utf8's context as used when exceptions are disabled
- choose the compact float prefix in a helper rather than with nested
  conditional operators (clang-tidy)
- use auto for the cast in the BON8 integer reader (clang-tidy)
- write the int32 minimum test values as long long literals (MSVC C4146)

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Amalgamate

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Read BON8 strings in bulk from contiguous input

- copy the valid UTF-8 of a string in one step when the input is
  contiguous (twitter.json is read in 1.68 instead of 2.52 ms,
  jeopardy.json in 196 instead of 297 ms, close to CBOR and MessagePack)
- share the new valid_utf8_prefix() with the writer's UTF-8 check, which
  now skips ASCII 8 bytes at a time
- let the fuzzer check that contiguous and stream input give the same
  value or error, and test both paths in the unit tests
- clarify that a second 0xFF after a string is an empty string

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Link the BON8 functions from the other binary format pages

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Name the bulk scan flag after the input, not BON8

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Read BSON keys in bulk from contiguous input

BSON keys (and array indices) are C-style strings, which were read byte
by byte. For contiguous input they are now read up to their \x00-byte in
one step, using the same bulk_scan flag as BON8 strings: twitter.json is
read in 1.46 instead of 2.01 ms, citm_catalog.json in 2.93 instead of
3.33 ms, jeopardy.json in 182 instead of 207 ms. canada.json, whose keys
are almost all one-digit array indices, takes 2 % longer.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix the BON8 CI failures of the bulk-read tests

- skip the contiguous-versus-stream tests of BON8 strings and BSON keys
  when exceptions are disabled: they catch the parse errors of invalid
  input, and without exceptions the library aborts instead
- use static_cast for the int64 test value (google-readability-casting)

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Move the explicit basic_json instantiation into its own test file

Linking test-regression3_cpp20 with clang and MinGW failed with
"relocation truncated to fit: IMAGE_REL_AMD64_REL32 against `.rdata'",
as test-regression2 did before #5511. The explicit instantiation of
basic_json<> for #4825 compiles every member function, including the
BON8 reader and writer, into that object, and it was already close to
the limit (2,226,104 bytes on develop, 2,234,960 with BON8; clang -O1,
C++20).

Give the instantiation a file of its own: unit-regression3 is now
1,594,736 bytes and unit-explicit_instantiation 1,095,064. The new file
mentions JSON_HAS_CPP_17 and JSON_HAS_CPP_20 so it keeps being built
for the C++17 standard the regression was about.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Convert the bytes of the BON8 test strings explicitly

The str() helper constructed a std::string from a byte range, which
converts each unsigned char implicitly; -fsanitize=integer reports that
for bytes of 0x80 and above (ci_test_clang_sanitizer).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann
2026-09-27 16:56:21 +02:00
committed by GitHub
parent f682cd2ef1
commit 1e101ecac1
58 changed files with 3950 additions and 53 deletions
+614 -1
View File
@@ -28,6 +28,7 @@
#include <nlohmann/detail/input/input_adapters.hpp>
#include <nlohmann/detail/input/json_sax.hpp>
#include <nlohmann/detail/input/lexer.hpp>
#include <nlohmann/detail/input/string_scan.hpp>
#include <nlohmann/detail/macro_scope.hpp>
#include <nlohmann/detail/meta/is_sax.hpp>
#include <nlohmann/detail/meta/type_traits.hpp>
@@ -84,7 +85,7 @@ JSON_INLINE_VARIABLE constexpr std::size_t max_valueless_container_size = 1 << 2
///////////////////
/*!
@brief deserialization of CBOR, MessagePack, and UBJSON values
@brief deserialization of BJData, BON8, BSON, CBOR, MessagePack, and UBJSON values
*/
template<typename BasicJsonType, typename InputAdapterType, typename SAX = json_sax_dom_parser<BasicJsonType, InputAdapterType>>
class binary_reader
@@ -98,6 +99,11 @@ class binary_reader
using char_type = typename InputAdapterType::char_type;
using char_int_type = typename char_traits<char_type>::int_type;
/// whether the input is a contiguous block of bytes that can be inspected
/// and consumed in bulk (as in the lexer); used by @ref get_bon8_string_bulk
static constexpr bool bulk_scan =
input_adapter_supports_bulk_scan<InputAdapterType>(is_detected<detect_supports_bulk_scan, InputAdapterType> {});
public:
/*!
@brief create a binary reader
@@ -132,6 +138,7 @@ class binary_reader
{
sax = sax_;
container_stack.clear();
bon8_pushback_size = 0;
bool result = false;
switch (format)
@@ -153,6 +160,10 @@ class binary_reader
result = parse_ubjson_internal();
break;
case input_format_t::bon8:
result = parse_bon8_internal();
break;
case input_format_t::json: // LCOV_EXCL_LINE
default: // LCOV_EXCL_LINE
JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
@@ -165,6 +176,11 @@ class binary_reader
{
get_ignore_noop();
}
else if (input_format == input_format_t::bon8)
{
// a string that ends a container hands back the byte after it
get_bon8();
}
else
{
get();
@@ -396,6 +412,11 @@ class binary_reader
*/
bool get_bson_cstr(string_t& result)
{
if (get_bson_cstr_bulk(result, std::integral_constant<bool, bulk_scan> {}))
{
return true;
}
auto out = std::back_inserter(result);
while (true)
{
@@ -412,6 +433,46 @@ class binary_reader
}
}
/*!
@brief read a C-style string from contiguous input in one step
@param[in,out] result the string to append to
@return whether the string was read; if the input has no \x00-byte, nothing
is read, and @ref get_bson_cstr reports the end of the input
*/
bool get_bson_cstr_bulk(string_t& result, std::true_type /*bulk*/)
{
const std::size_t remaining = ia.bulk_remaining();
if (remaining == 0)
{
return false;
}
const auto* const data = reinterpret_cast<const unsigned char*>(ia.bulk_data());
// a plain loop rather than std::memchr: most keys are short (array
// indices are keys, too), and the call would cost more than it saves
std::size_t length = 0;
while (length < remaining && data[length] != 0x00)
{
++length;
}
if (length == remaining)
{
return false;
}
result.append(reinterpret_cast<const typename string_t::value_type*>(data), length);
// consume the string and its \x00-byte, as the byte-wise path does
ia.bulk_skip(length + 1);
chars_read += length + 1;
current = 0x00;
return true;
}
/// input that is not contiguous: C-style strings are read byte by byte
bool get_bson_cstr_bulk(string_t& /*result*/, std::false_type /*bulk*/) const noexcept
{
return false;
}
/*!
@brief Parses a zero-terminated string of length @a len from the BSON
input.
@@ -3199,6 +3260,549 @@ class binary_reader
}
}
//////////
// BON8 //
//////////
/*!
@brief get the next byte of a BON8 value
A BON8 string has no length prefix and no mandatory terminator: it ends at
the first byte that cannot continue it, which is already the first byte (or,
for an integer that begins with a UTF-8 lead byte, the first two bytes) of
whatever follows. The string reader hands those bytes back with
@ref unget_bon8, and every BON8 read goes through this function so that
they are seen again.
@return character read from the input
*/
char_int_type get_bon8()
{
if (bon8_pushback_size != 0)
{
++chars_read;
return current = bon8_pushback[--bon8_pushback_size];
}
return get();
}
/*!
@brief hand a byte back so that the next @ref get_bon8 returns it again
@param[in] c the byte to hand back; bytes handed back are returned in
reverse order
*/
void unget_bon8(const char_int_type c)
{
// At most two bytes are ever handed back: a byte is only handed back
// right after it was read with get_bon8(), and the only place that
// hands back two bytes (a lead byte and the byte after it) read both
// of them in a row, which emptied the buffer first. This is an
// invariant of the reader rather than a property of the input, so
// an assertion suffices (the fuzzers are built with assertions).
JSON_ASSERT(bon8_pushback_size < bon8_pushback.size());
bon8_pushback[bon8_pushback_size++] = c;
--chars_read;
}
/*!
@param[in] c a byte
@return whether @a c is a UTF-8 continuation byte (0x80..0xBF)
*/
static constexpr bool is_bon8_continuation(const char_int_type c) noexcept
{
return 0x80 <= c && c <= 0xBF;
}
/*!
@brief report a parse error at the last read byte
@param[in] detail a detailed error message
@param[in] context further context information
@return false
*/
bool bon8_error(const std::string& detail, const char* context)
{
auto last_token = get_token_string();
return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read,
exception_message(input_format_t::bon8, concat(detail, ": 0x", last_token), context), nullptr));
}
/*!
@brief read a BON8 value and everything nested inside it
Reads values until the one that was begun here is complete, resuming the
enclosing container after each element, so that the nesting depth of the
input costs heap rather than native stack (see #5104).
@return whether reading the value succeeded
*/
bool parse_bon8_internal()
{
// the key currently being read; hoisted out of the loop so that its
// capacity is reused across elements and across nesting levels
string_t key;
while (true)
{
if (!container_stack.empty())
{
// a copy, not a reference: it must stay valid across the
// pop_back() below, which destroys the container_stack element
// it would otherwise alias
const container_frame top = container_stack.back();
bool at_end = false;
if (top.remaining != npos)
{
// counted container (0x80..0x84, 0x86..0x8A): it ends once
// its elements have been read
at_end = (top.remaining == 0);
if (!at_end)
{
// claim the element about to be read
--container_stack.back().remaining;
}
}
else
{
// container 0x85 or 0x8B: it ends at an end-of-container
// marker (0xFE); any other byte begins the next element
at_end = (get_bon8() == 0xFE);
if (!at_end)
{
unget_bon8(current);
}
}
if (at_end)
{
container_stack.pop_back();
if (JSON_HEDLEY_UNLIKELY(top.is_object ? !sax->end_object() : !sax->end_array()))
{
return false;
}
// the value begun here is complete once its container is
if (container_stack.empty())
{
return true;
}
continue;
}
if (top.is_object)
{
key.clear();
if (JSON_HEDLEY_UNLIKELY(!get_bon8_key(key) || !sax->key(key)))
{
return false;
}
}
}
if (JSON_HEDLEY_UNLIKELY(!parse_bon8_value()))
{
return false;
}
// a value that opened a container left it on the stack; one that
// did not, and that was not inside a container, was the whole value
if (container_stack.empty())
{
return true;
}
}
}
/*!
@brief read one BON8 value
Reads a single value and passes it to the SAX parser. A value that begins
a container is not read to its end: the container is opened with
@ref enter_container and its elements are read by
@ref parse_bon8_internal, so that nesting does not consume native stack.
@return whether reading the value succeeded
*/
bool parse_bon8_value()
{
const auto byte = get_bon8();
if (byte == char_traits<char_type>::eof())
{
return unexpect_eof(input_format_t::bon8, "value");
}
// string: ASCII character
if (byte <= 0x7F)
{
string_t s;
unget_bon8(byte);
return get_bon8_string(s) && sax->string(s);
}
// array with 0..4 elements
if (byte <= 0x84)
{
return enter_array(static_cast<std::size_t>(byte - 0x80));
}
// array terminated by 0xFE
if (byte == 0x85)
{
return enter_array(npos);
}
// object with 0..4 members
if (byte <= 0x8A)
{
return enter_object(static_cast<std::size_t>(byte - 0x86));
}
switch (byte)
{
case 0x8B: // object terminated by 0xFE
return enter_object(npos);
case 0x8C: // int32
{
std::int32_t number{};
return get_number(input_format_t::bon8, number) && emit_bon8_integer(number);
}
case 0x8D: // int64
{
std::int64_t number{};
return get_number(input_format_t::bon8, number) && emit_bon8_integer(number);
}
case 0x8E: // binary32
{
float number{};
return get_number(input_format_t::bon8, number) && sax->number_float(static_cast<number_float_t>(number), "");
}
case 0x8F: // binary64
{
double number{};
return get_number(input_format_t::bon8, number) && sax->number_float(static_cast<number_float_t>(number), "");
}
case 0xF8:
return sax->boolean(false);
case 0xF9:
return sax->boolean(true);
case 0xFA:
return sax->null();
case 0xFB:
return sax->number_float(static_cast<number_float_t>(-1.0), "");
case 0xFC:
return sax->number_float(static_cast<number_float_t>(0.0), "");
case 0xFD:
return sax->number_float(static_cast<number_float_t>(1.0), "");
case 0xFF: // empty string
{
string_t s;
return sax->string(s);
}
default:
break;
}
// integer 0..39
if (byte <= 0xB7)
{
return sax->number_unsigned(static_cast<number_unsigned_t>(byte - 0x90));
}
// integer -1..-10
if (byte <= 0xC1)
{
return sax->number_integer(-1 - static_cast<number_integer_t>(byte - 0xB8));
}
// 0xC2..0xF7: a UTF-8 lead byte begins a string if a continuation
// byte follows and an integer otherwise
if (byte <= 0xF7)
{
const auto second = get_bon8();
if (is_bon8_continuation(second))
{
string_t s;
unget_bon8(second);
unget_bon8(byte);
return get_bon8_string(s) && sax->string(s);
}
return get_bon8_integer(byte, second);
}
// 0xFE: end of container where a value is expected
return bon8_error("invalid byte", "value");
}
/*!
@brief pass an integer to the SAX parser
Non-negative integers are passed as unsigned, negative integers as signed
numbers, like the other binary formats do.
@param[in] number the integer
@return whether the SAX parser accepted the value
*/
bool emit_bon8_integer(const std::int64_t number)
{
if (number >= 0)
{
return sax->number_unsigned(static_cast<number_unsigned_t>(number));
}
return sax->number_integer(static_cast<number_integer_t>(number));
}
/*!
@brief read an integer encoded in 2..4 bytes
The first byte is a UTF-8 lead byte (0xC2..0xF7) that is followed by a
byte that is not a continuation byte: 0x00..0x7F for positive and
0xC0..0xFF for negative integers. The lead byte's low bits and the second
byte's low 7 (positive) or 6 (negative) bits are the most significant bits
of the value; 3- and 4-byte integers add one or two full bytes. Each range
starts where the shorter one ends, so no value has two encodings of the
same length.
@param[in] lead the first byte (0xC2..0xF7)
@param[in] second the second byte
@return whether reading the integer succeeded
*/
bool get_bon8_integer(const char_int_type lead, const char_int_type second)
{
if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::bon8, "number")))
{
return false;
}
const bool negative = second >= 0xC0;
auto value = static_cast<std::int64_t>(negative ? (second & 0x3F) : second);
std::int64_t offset = 0;
int extra_bytes = 0;
if (lead <= 0xDF)
{
value |= static_cast<std::int64_t>(lead - 0xC2) << (negative ? 6 : 7);
offset = negative ? 11 : 40;
}
else if (lead <= 0xEF)
{
value |= static_cast<std::int64_t>(lead & 0x0F) << (negative ? 6 : 7);
offset = negative ? 1931 : 3880;
extra_bytes = 1;
}
else
{
value |= static_cast<std::int64_t>(lead & 0x07) << (negative ? 6 : 7);
offset = negative ? 264075 : 528168;
extra_bytes = 2;
}
for (int i = 0; i < extra_bytes; ++i)
{
if (JSON_HEDLEY_UNLIKELY(get_bon8() == char_traits<char_type>::eof()))
{
return unexpect_eof(input_format_t::bon8, "number");
}
value = (value << 8) | static_cast<std::int64_t>(current);
}
return negative ? sax->number_integer(static_cast<number_integer_t>(-(value + offset)))
: sax->number_unsigned(static_cast<number_unsigned_t>(value + offset));
}
/*!
@brief read an object key
A key must be a string, so its first byte must be an ASCII character, a
UTF-8 lead byte followed by a continuation byte, or 0xFF (empty string).
@param[out] result the key
@return whether reading the key succeeded
*/
bool get_bon8_key(string_t& result)
{
const auto byte = get_bon8();
if (byte == char_traits<char_type>::eof())
{
return unexpect_eof(input_format_t::bon8, "key");
}
if (byte == 0xFF)
{
return true;
}
if (byte <= 0x7F)
{
unget_bon8(byte);
return get_bon8_string(result);
}
if (0xC2 <= byte && byte <= 0xF7)
{
const auto second = get_bon8();
unget_bon8(second);
if (is_bon8_continuation(second))
{
unget_bon8(byte);
return get_bon8_string(result);
}
// an integer: report its first byte rather than the one after it
current = byte;
}
return bon8_error("expected a string; last byte", "key");
}
/*!
@brief append the run of valid UTF-8 at the read position to a string
For contiguous input, the ASCII characters and complete well-formed UTF-8
sequences at the read position are appended to @a result in one step. The
byte that stops the run (an end-of-string marker, the first byte of the
next value, or an ill-formed byte) is left for @ref get_bon8_string, so
that strings end and errors are reported exactly as without this step.
@param[in,out] result the string to append to
*/
void get_bon8_string_bulk(string_t& result, std::true_type /*bulk*/)
{
// bytes handed back must be read through get_bon8() first
if (bon8_pushback_size != 0)
{
return;
}
const std::size_t remaining = ia.bulk_remaining();
if (remaining == 0)
{
return;
}
const auto* const data = reinterpret_cast<const unsigned char*>(ia.bulk_data());
const std::size_t length = valid_utf8_prefix(data, remaining);
if (length != 0)
{
result.append(reinterpret_cast<const typename string_t::value_type*>(data), length);
ia.bulk_skip(length);
chars_read += length;
}
}
/// input that is not contiguous: strings are read byte by byte
void get_bon8_string_bulk(string_t& /*result*/, std::false_type /*bulk*/) const noexcept {}
/*!
@brief read a string
Reads UTF-8 characters until an end-of-string marker (0xFF), which is
consumed, or a byte that cannot continue the string, which is handed back
to be read as the start of the next value. The string must be valid UTF-8,
and it must not end at the end of the input: the last string of a message
is always terminated by 0xFF.
@param[out] result the string
@return whether reading the string succeeded
*/
bool get_bon8_string(string_t& result)
{
while (true)
{
get_bon8_string_bulk(result, std::integral_constant<bool, bulk_scan> {});
const auto byte = get_bon8();
if (byte == char_traits<char_type>::eof())
{
return unexpect_eof(input_format_t::bon8, "string");
}
// end of string
if (byte == 0xFF)
{
return true;
}
// ASCII character
if (byte <= 0x7F)
{
result.push_back(static_cast<typename string_t::value_type>(byte));
continue;
}
// a byte that cannot begin a character ends the string and begins
// the next value
if (byte < 0xC2 || byte > 0xF7)
{
unget_bon8(byte);
return true;
}
// a lead byte ends the string if no continuation byte follows: it
// is then the first byte of an integer
const auto second = get_bon8();
if (!is_bon8_continuation(second))
{
unget_bon8(second);
unget_bon8(byte);
return true;
}
// the valid range of the second byte excludes overlong forms,
// surrogates, and code points above U+10FFFF
// (RFC 3629, section 4)
int continuation_bytes = 0;
bool valid_second = true;
if (byte <= 0xDF)
{
continuation_bytes = 1;
}
else if (byte <= 0xEF)
{
continuation_bytes = 2;
valid_second = (byte != 0xE0 || second >= 0xA0) && (byte != 0xED || second <= 0x9F);
}
else
{
continuation_bytes = 3;
valid_second = byte <= 0xF4 && (byte != 0xF0 || second >= 0x90) && (byte != 0xF4 || second <= 0x8F);
}
if (JSON_HEDLEY_UNLIKELY(!valid_second))
{
return bon8_error("invalid UTF-8 byte", "string");
}
result.push_back(static_cast<typename string_t::value_type>(byte));
result.push_back(static_cast<typename string_t::value_type>(second));
for (int i = 1; i < continuation_bytes; ++i)
{
if (JSON_HEDLEY_UNLIKELY(get_bon8() == char_traits<char_type>::eof()))
{
return unexpect_eof(input_format_t::bon8, "string");
}
if (JSON_HEDLEY_UNLIKELY(!is_bon8_continuation(current)))
{
return bon8_error("invalid UTF-8 byte", "string");
}
result.push_back(static_cast<typename string_t::value_type>(current));
}
}
}
///////////////////////
// Utility functions //
///////////////////////
@@ -3497,6 +4101,10 @@ class binary_reader
error_msg += "BJData";
break;
case input_format_t::bon8:
error_msg += "BON8";
break;
case input_format_t::json: // LCOV_EXCL_LINE
default: // LCOV_EXCL_LINE
JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
@@ -3529,6 +4137,11 @@ class binary_reader
/// the containers that have been opened and not closed yet; see @ref container_frame
std::vector<container_frame> container_stack{};
/// BON8: bytes read past the end of a string, returned again by @ref get_bon8
std::array<char_int_type, 2> bon8_pushback{{}};
/// BON8: number of bytes in @ref bon8_pushback
std::size_t bon8_pushback_size = 0;
// excluded markers in bjdata optimized type
#define JSON_BINARY_READER_MAKE_BJD_OPTIMIZED_TYPE_MARKERS_ \
make_array<char_int_type>('F', 'H', 'N', 'S', 'T', 'Z', '[', '{')
@@ -34,7 +34,7 @@ namespace detail
{
/// the supported input formats
enum class input_format_t { json, cbor, msgpack, ubjson, bson, bjdata };
enum class input_format_t { json, cbor, msgpack, ubjson, bson, bjdata, bon8 };
////////////////////
// input adapters //
@@ -201,6 +201,43 @@ inline std::size_t validate_one_utf8(const unsigned char* data, std::size_t avai
return 0; // invalid, incomplete, or must be diagnosed by the byte path
}
// Return the length of the longest prefix of [data, data+n) that consists of
// ASCII characters and complete well-formed UTF-8 sequences; n if all of it is
// valid UTF-8. Unlike scalar_string_bulk_run(), quotes, escapes, and control
// characters are ordinary characters here. ASCII is skipped 8 bytes at a time.
inline std::size_t valid_utf8_prefix(const unsigned char* data, std::size_t n) noexcept
{
constexpr std::uint64_t high = 0x8080808080808080ull;
std::size_t pos = 0;
while (pos < n)
{
if (pos + 8 <= n)
{
std::uint64_t word = 0;
std::memcpy(&word, data + pos, sizeof(word));
if ((word & high) == 0)
{
pos += 8;
continue;
}
}
if (data[pos] < 0x80u)
{
++pos;
continue;
}
const std::size_t seq = validate_one_utf8(data + pos, n - pos);
if (seq == 0)
{
break; // ill-formed or truncated
}
pos += seq;
}
return pos;
}
// Scalar (C++11) computation of the bulk run length: the number of leading
// bytes in [data, data+n) that are ordinary ASCII or complete well-formed UTF-8
// sequences, stopping before the first byte that needs individual handling (the
@@ -25,6 +25,7 @@
#endif
#include <nlohmann/detail/input/binary_reader.hpp>
#include <nlohmann/detail/input/string_scan.hpp>
#include <nlohmann/detail/macro_scope.hpp>
#include <nlohmann/detail/output/output_adapters.hpp>
#include <nlohmann/detail/string_concat.hpp>
@@ -76,7 +77,7 @@ std::size_t binary_reserve_hint(const BasicJsonType& j)
}
/*!
@brief serialization to CBOR and MessagePack values
@brief serialization to BJData, BON8, BSON, CBOR, MessagePack, and UBJSON values
*/
template<typename BasicJsonType, typename CharType, typename OutputSinkType = output_adapter_sink<CharType>>
class binary_writer
@@ -873,6 +874,21 @@ class binary_writer
}
}
/*!
@param[in] j JSON value to serialize
*/
void write_bon8(const BasicJsonType& j)
{
bool string_open = false;
write_bon8_value(j, string_open);
// the last string of a message must be terminated
if (string_open)
{
oa.write_character(to_char_type(0xFF));
}
}
private:
//////////
// BSON //
@@ -1431,6 +1447,28 @@ class binary_writer
return to_char_type(0xCB); // float 64
}
/// @return the BON8 type marker for binary32 (float) or binary64 (double)
template<typename FloatType>
static constexpr CharType get_bon8_float_prefix()
{
return to_char_type(std::is_same<FloatType, float>::value ? 0x8E : 0x8F);
}
/// @return the type marker for a FloatType value in @a format (CBOR, MessagePack, or BON8)
template<typename FloatType>
static CharType get_compact_float_prefix(const detail::input_format_t format)
{
if (format == detail::input_format_t::cbor)
{
return get_cbor_float_prefix(FloatType{});
}
if (format == detail::input_format_t::bon8)
{
return get_bon8_float_prefix<FloatType>();
}
return get_msgpack_float_prefix(FloatType{});
}
////////////
// UBJSON //
////////////
@@ -2050,6 +2088,322 @@ class binary_writer
return false;
}
//////////
// BON8 //
//////////
/*!
@brief write a BON8 value
A string is written without length or terminator: it ends at the first
byte that cannot continue it, which is the first byte of any non-string
value and of the end-of-container marker 0xFE. It only needs an explicit
end-of-string marker (0xFF) when it is empty, when another string follows,
or when it is the last thing in the message.
@param[in] j JSON value to serialize
@param[in,out] string_open whether the output ends with a non-empty
string that has not been terminated with 0xFF
*/
void write_bon8_value(const BasicJsonType& j, bool& string_open)
{
switch (j.type())
{
case value_t::null:
{
write_bon8_marker(0xFA, string_open);
break;
}
case value_t::boolean:
{
write_bon8_marker(j.m_data.m_value.boolean ? 0xF9 : 0xF8, string_open);
break;
}
case value_t::number_unsigned:
{
if (j.m_data.m_value.number_unsigned > static_cast<typename BasicJsonType::number_unsigned_t>((std::numeric_limits<std::int64_t>::max)()))
{
JSON_THROW(out_of_range::create(407, concat("integer number ", std::to_string(j.m_data.m_value.number_unsigned), " cannot be represented by BON8 as it does not fit int64"), &j));
}
write_bon8_integer(static_cast<std::int64_t>(j.m_data.m_value.number_unsigned));
string_open = false;
break;
}
case value_t::number_integer:
{
write_bon8_integer(static_cast<std::int64_t>(j.m_data.m_value.number_integer));
string_open = false;
break;
}
case value_t::number_float:
{
write_bon8_float(j.m_data.m_value.number_float);
string_open = false;
break;
}
case value_t::string:
{
write_bon8_string(*j.m_data.m_value.string, string_open, j);
break;
}
case value_t::array:
{
const auto N = j.m_data.m_value.array->size();
// 0x80..0x84: array with 0..4 elements; 0x85: array ended by 0xFE
write_bon8_marker(static_cast<std::uint8_t>(N <= 4 ? 0x80 + N : 0x85), string_open);
for (const auto& el : *j.m_data.m_value.array)
{
write_bon8_value(el, string_open);
}
if (N > 4)
{
write_bon8_marker(0xFE, string_open);
}
break;
}
case value_t::object:
{
const auto N = j.m_data.m_value.object->size();
// 0x86..0x8A: object with 0..4 members; 0x8B: object ended by 0xFE
write_bon8_marker(static_cast<std::uint8_t>(N <= 4 ? 0x86 + N : 0x8B), string_open);
for (const auto& el : *j.m_data.m_value.object)
{
write_bon8_string(el.first, string_open, j);
write_bon8_value(el.second, string_open);
}
if (N > 4)
{
write_bon8_marker(0xFE, string_open);
}
break;
}
case value_t::binary:
{
// BON8 has no binary type: write the bytes as an array of
// integers, like UBJSON and BJData do
const auto N = j.m_data.m_value.binary->size();
write_bon8_marker(static_cast<std::uint8_t>(N <= 4 ? 0x80 + N : 0x85), string_open);
for (std::size_t i = 0; i < N; ++i)
{
// the cast is needed for binary types whose value type
// is not an integer (e.g., std::byte)
write_bon8_integer(static_cast<std::uint8_t>(j.m_data.m_value.binary->data()[i]));
}
if (N > 4)
{
write_bon8_marker(0xFE, string_open);
}
break;
}
case value_t::discarded:
default:
break;
}
}
/*!
@brief write a single byte that is not part of a string
@param[in] marker the byte to write
@param[out] string_open set to false, because the output no longer ends
with a string; see @ref write_bon8_value
*/
void write_bon8_marker(const std::uint8_t marker, bool& string_open)
{
oa.write_character(to_char_type(marker));
string_open = false;
}
/*!
@brief write a string
@param[in] s the string to write
@param[in,out] string_open see @ref write_bon8_value
@param[in] context the value the string belongs to (for diagnostics)
@throw type_error.316 if @a s is not valid UTF-8, because the end of a
string is determined from its encoding
*/
void write_bon8_string(const string_t& s, bool& string_open, const BasicJsonType& context)
{
check_bon8_utf8(s, context);
// a string that follows another string terminates it
if (string_open)
{
oa.write_character(to_char_type(0xFF));
}
if (s.empty())
{
// the empty string is just the end-of-string marker
oa.write_character(to_char_type(0xFF));
string_open = false;
}
else
{
oa.write_characters(reinterpret_cast<const CharType*>(s.data()), s.size());
string_open = true;
}
}
/*!
@brief check that a string is valid UTF-8 (RFC 3629)
@param[in] s the string to check
@param[in] context the value the string belongs to (for diagnostics)
@throw type_error.316 if @a s is not valid UTF-8; the message names the
first byte of the first invalid or incomplete sequence
*/
static void check_bon8_utf8(const string_t& s, const BasicJsonType& context)
{
static_cast<void>(context); // only used when exceptions are enabled
const auto* data = reinterpret_cast<const unsigned char*>(s.data());
const std::size_t valid = valid_utf8_prefix(data, s.size());
if (JSON_HEDLEY_UNLIKELY(valid != s.size()))
{
JSON_THROW(type_error::create(316, concat("invalid UTF-8 byte at index ", std::to_string(valid), ": 0x", hex_byte(data[valid])), &context));
}
}
/// @return a byte as two uppercase hexadecimal digits
static std::string hex_byte(const std::uint8_t byte)
{
std::string result = "00";
constexpr const char* nibble_to_hex = "0123456789ABCDEF";
result[0] = nibble_to_hex[byte / 16];
result[1] = nibble_to_hex[byte % 16];
return result;
}
/*!
@brief write an integer in the shortest encoding
Integers from -10 to 39 take one byte. Up to -33818506 and 67637031, an
integer takes 2 to 4 bytes that begin with a UTF-8 lead byte (0xC2..0xF7)
followed by a byte that is not a continuation byte: 0x00..0x7F for
positive and 0xC0..0xFF for negative integers. Each range starts where the
shorter one ends. Larger integers are written as int32 (0x8C) or int64
(0x8D) in big-endian byte order.
@param[in] value the integer to write
*/
void write_bon8_integer(std::int64_t value)
{
if (value < (std::numeric_limits<std::int32_t>::min)() || value > (std::numeric_limits<std::int32_t>::max)())
{
oa.write_character(to_char_type(0x8D));
write_number(value);
}
else if (value < -33818506 || value > 67637031)
{
oa.write_character(to_char_type(0x8C));
write_number(static_cast<std::int32_t>(value));
}
else if (value <= -264075)
{
value = -(value + 264075);
write_bon8_bytes(0xF0 + ((value >> 22) & 0x07), 0xC0 + ((value >> 16) & 0x3F), value >> 8, value);
}
else if (value <= -1931)
{
value = -(value + 1931);
write_bon8_bytes(0xE0 + ((value >> 14) & 0x0F), 0xC0 + ((value >> 8) & 0x3F), value);
}
else if (value <= -11)
{
value = -(value + 11);
write_bon8_bytes(0xC2 + ((value >> 6) & 0x1F), 0xC0 + (value & 0x3F));
}
else if (value <= -1)
{
write_bon8_bytes(0xB8 - (value + 1));
}
else if (value <= 39)
{
write_bon8_bytes(0x90 + value);
}
else if (value <= 3879)
{
value -= 40;
write_bon8_bytes(0xC2 + ((value >> 7) & 0x1F), value & 0x7F);
}
else if (value <= 528167)
{
value -= 3880;
write_bon8_bytes(0xE0 + ((value >> 15) & 0x0F), (value >> 8) & 0x7F, value);
}
else
{
value -= 528168;
write_bon8_bytes(0xF0 + ((value >> 23) & 0x07), (value >> 16) & 0x7F, value >> 8, value);
}
}
/// write the low byte of each argument
template<typename... Bytes>
void write_bon8_bytes(const Bytes... bytes)
{
const std::array<CharType, sizeof...(Bytes)> buffer{{to_char_type(static_cast<std::uint8_t>(bytes & 0xFF))...}};
oa.write_characters(buffer.data(), buffer.size());
}
/*!
@brief write a floating-point number
-1.0, +0.0, and 1.0 take one byte. Other numbers are written as binary32
(0x8E) if that loses no precision, and as binary64 (0x8F) otherwise; -0.0,
infinities, and NaN are always written as binary32, NaN as 0x7F800001.
@param[in] n the number to write
*/
void write_bon8_float(const number_float_t n)
{
#ifdef __GNUC__
JSON_HEDLEY_DIAGNOSTIC_PUSH
JSON_HEDLEY_PRAGMA(GCC diagnostic ignored "-Wfloat-equal")
#endif
if (n == static_cast<number_float_t>(-1))
{
oa.write_character(to_char_type(0xFB));
}
else if (n == static_cast<number_float_t>(0) && !std::signbit(n))
{
oa.write_character(to_char_type(0xFC));
}
else if (n == static_cast<number_float_t>(1))
{
oa.write_character(to_char_type(0xFD));
}
else if (std::isnan(n))
{
write_bon8_bytes(0x8E, 0x7F, 0x80, 0x00, 0x01);
}
else
{
write_compact_float(n, detail::input_format_t::bon8);
}
#ifdef __GNUC__
JSON_HEDLEY_DIAGNOSTIC_POP
#endif
}
///////////////////////
// Utility functions //
///////////////////////
@@ -2184,16 +2538,12 @@ class binary_writer
static_cast<double>(n) <= static_cast<double>((std::numeric_limits<float>::max)()) &&
static_cast<double>(static_cast<float>(n)) == static_cast<double>(n))))
{
oa.write_character(format == detail::input_format_t::cbor
? get_cbor_float_prefix(static_cast<float>(n))
: get_msgpack_float_prefix(static_cast<float>(n)));
oa.write_character(get_compact_float_prefix<float>(format));
write_number(static_cast<float>(n));
}
else
{
oa.write_character(format == detail::input_format_t::cbor
? get_cbor_float_prefix(n)
: get_msgpack_float_prefix(n));
oa.write_character(get_compact_float_prefix<number_float_t>(format));
write_number(n);
}
#ifdef __GNUC__
+61
View File
@@ -5290,6 +5290,30 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
binary_writer<char>(o).write_bson(j);
}
/// @brief create a BON8 serialization of a given JSON value
/// @sa https://json.nlohmann.me/api/basic_json/to_bon8/
static std::vector<std::uint8_t> to_bon8(const basic_json& j)
{
std::vector<std::uint8_t> result;
result.reserve(detail::binary_reserve_hint(j));
vector_writer(result).write_bon8(j);
return result;
}
/// @brief create a BON8 serialization of a given JSON value
/// @sa https://json.nlohmann.me/api/basic_json/to_bon8/
static void to_bon8(const basic_json& j, detail::output_adapter<std::uint8_t> o)
{
binary_writer<std::uint8_t>(o).write_bon8(j);
}
/// @brief create a BON8 serialization of a given JSON value
/// @sa https://json.nlohmann.me/api/basic_json/to_bon8/
static void to_bon8(const basic_json& j, detail::output_adapter<char> o)
{
binary_writer<char>(o).write_bon8(j);
}
/// @brief create a JSON value from an input in CBOR format
/// @sa https://json.nlohmann.me/api/basic_json/from_cbor/
template<typename InputType>
@@ -5523,6 +5547,43 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
return result;
}
/// @brief create a JSON value from an input in BON8 format
/// @sa https://json.nlohmann.me/api/basic_json/from_bon8/
template<typename InputType>
JSON_HEDLEY_WARN_UNUSED_RESULT
static basic_json from_bon8(InputType&& i,
const bool strict = true,
const bool allow_exceptions = true)
{
basic_json result;
auto ia = detail::input_adapter(std::forward<InputType>(i));
detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::bon8).sax_parse(input_format_t::bon8, &sdp, strict)) // cppcheck-suppress[accessMoved]
{
result = value_t::discarded;
}
return result;
}
/// @brief create a JSON value from an input in BON8 format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
/// @sa https://json.nlohmann.me/api/basic_json/from_bon8/
template<typename IteratorType, typename SentinelType = IteratorType,
detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
JSON_HEDLEY_WARN_UNUSED_RESULT
static basic_json from_bon8(IteratorType first, SentinelType last,
const bool strict = true,
const bool allow_exceptions = true)
{
basic_json result;
auto ia = detail::input_adapter(std::move(first), std::move(last));
detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::bon8).sax_parse(input_format_t::bon8, &sdp, strict)) // cppcheck-suppress[accessMoved]
{
result = value_t::discarded;
}
return result;
}
/// @brief create a JSON value from an input in BSON format
/// @sa https://json.nlohmann.me/api/basic_json/from_bson/
template<typename InputType>