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Merge branch claude/perf-contiguous-parser into claude/perf-swar-reduced-form

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Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann committed 2026-11-07 10:20:22 +01:00
2 parents a612dd8141 c1104d20b8
commit 56463e7a3a
12 files changed
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docs/mkdocs/docs/api/macros/json_diagnostic_positions.md
+3
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@@ -34,6 +34,9 @@ or quotes.
Note that enabling this macro increases the size of every JSON value by two `std::size_t` fields and adds slight runtime
overhead to parsing, copying JSON value objects, and the generation of error messages for exceptions. It also causes
these values to be reported in those error messages.
In addition, `parse()`, `accept()`, and `sax_parse()` no longer use the
[faster path for input in one block of memory](../../features/parsing/index.md#input-sources-and-performance), so
parsing a string or a buffer is slower than without the macro.
If [`JSON_DIAGNOSTICS`](json_diagnostics.md) is also set, the message contains the path and the byte range, such as
`(/1) (bytes 4-8)`. An exception about the root value has no path and only the range, such as `(bytes 0-4)`.
docs/mkdocs/docs/api/macros/json_disable_unlocked_file_io.md
+14 -4
View File
@@ -5,7 +5,9 @@
```
When defined to `1`, parsing from a `#!cpp FILE*` reads every character with `std::fgetc`, as in version 3.12.0 and
earlier, instead of locking the file once and reading it with the unlocked stdio functions.
earlier, instead of locking the file once and reading it with the unlocked stdio functions. This also turns off the
scan of the `FILE`'s buffer in bulk (see below), which [`JSON_DISABLE_STREAM_BULK_SCAN`](json_disable_stream_bulk_scan.md)
does not affect.
It does not change any result: values, exceptions, and the position of the file after parsing are the same either way.
Only the speed and the locking of the file differ (see the notes on locking below).
@@ -37,9 +39,17 @@ The default value is `0`: the file is locked once and read with the unlocked std
| Microsoft (MSVC, clang-cl) | `_lock_file`, `_fgetc_nolock`, `_unlock_file` |
| others (e.g., musl, MinGW, newlib) | `std::fgetc`, as before |
This makes parsing from a `FILE*` 3 to 4 times as fast with the Apple C library and 1.1 to 1.3 times as fast with
glibc, whose locking is cheaper. The binary formats ([`from_cbor`](../basic_json/from_cbor.md),
[`from_msgpack`](../basic_json/from_msgpack.md), ...) read from a `FILE*` the same way.
With glibc and the Apple C library, the parser also scans the characters that the `FILE` already holds in its
buffer in bulk, as it scans the get area of a stream (see
[`JSON_DISABLE_STREAM_BULK_SCAN`](json_disable_stream_bulk_scan.md)): it reads the same fields of the `FILE` that
the C library's own `getc_unlocked` reads, and it consumes exactly the characters that `getc_unlocked` would have
returned, so the file is left where it was left before.
Locking the file once makes parsing from a `FILE*` 3 to 4 times as fast with the Apple C library and 1.1 to 1.3
times as fast with glibc, whose locking is cheaper. Scanning the buffer in bulk makes `parse()` another 1.7 to 2.6
times as fast (and `accept()` 2.9 to 4.4 times), about as fast as parsing from a `std::ifstream`. The binary
formats ([`from_cbor`](../basic_json/from_cbor.md), [`from_msgpack`](../basic_json/from_msgpack.md), ...) read
from a `FILE*` the same way.
!!! note "Locking"
docs/mkdocs/docs/features/parsing/index.md
+4 -1
View File
@@ -77,13 +77,16 @@ them faster than others:
|--------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------|
| strings, string views, string literals, contiguous containers, pointer or iterator ranges over contiguous memory | the whole input is scanned in bulk: runs of string characters, numbers, and indentation are recognized several bytes at a time |
| `#!cpp std::istream` (`#!cpp std::ifstream`, `#!cpp std::istringstream`, ...) | the characters the stream buffer holds are scanned in bulk like a string; the stream buffer is asked for more when they are used up |
| `#!cpp FILE*` | one character at a time, with the file locked once for the whole parse |
| `#!cpp FILE*` | with glibc and the Apple C library, the characters the `FILE` holds in its buffer are scanned in bulk like a stream's; elsewhere one character at a time; the file is locked once for the whole parse |
| other iterator ranges (e.g., `#!cpp std::list<char>`, `#!cpp std::istreambuf_iterator<char>`), wide strings | one character at a time |
Input in one block of memory is read even faster with the default options (no
[parser callback](../../api/basic_json/parser_callback_t.md), no comments, no trailing commas, and for `sax_parse()`
`strict = true`): `parse()`, `accept()`, and `sax_parse()` then read the grammar and the tokens in one loop over the
memory. Only after an error do `parse()` and `sax_parse()` read the input again, to report the error exactly as before.
This faster path is not used when [`JSON_DIAGNOSTIC_POSITIONS`](../../api/macros/json_diagnostic_positions.md) is
enabled, because the positions are recorded by the default parser: the input is then parsed as before, at the same speed
as before.
Parsing a file from a `#!cpp std::ifstream` therefore takes about 1.15 to 1.45 times as long as reading the whole file
into a `#!cpp std::string` first and parsing that, but it needs no memory for a copy of the file. The stream is never read
docs/mkdocs/docs/features/performance.md
+2 -2
View File
@@ -27,8 +27,8 @@ A `#!cpp std::istream` (including `#!cpp std::ifstream`) gets the same bulk scan
characters its stream buffer already holds (the *get area*) and asks the stream buffer for more only when they are used
up. Nothing is read ahead, so the stream is left exactly where it would be after reading one character at a time, and
[`operator>>`](../api/operator_gtgt.md) can still read several values from one stream. A stream buffer without a get
area is read one character at a time. A `#!cpp FILE*` is still read one character at a time, but `file_input_adapter`
locks the file once per parse instead of once per character. See
area is read one character at a time. A `#!cpp FILE*` is locked once per parse instead of once per character, and with
glibc and the Apple C library, the characters in its buffer are scanned in bulk as a stream's get area is. See
[input sources and performance](parsing/index.md#input-sources-and-performance) for the full table. Parsing from a
stream takes about 1.15 to 1.45 times as long as parsing an equivalent `#!cpp std::string`, which `parse()` reads with
a parser of its own (see there).
include/nlohmann/detail/input/binary_reader.hpp
+38
View File
@@ -4887,6 +4887,14 @@ class binary_reader
const char* context,
ContainerType& result)
{
// a string that is in the block of input as a whole is appended from
// it, without the zero-filling resize() below
constexpr bool from_block = bulk_scan && std::is_same<ContainerType, string_t>::value;
if (append_from_block(len, result, std::integral_constant<bool, from_block> {}))
{
return true;
}
// upper bound on the number of bytes read (and allocated) per chunk
constexpr std::size_t chunk_size = 4096;
@@ -4923,6 +4931,36 @@ class binary_reader
return true;
}
/// append the @a len bytes at the current position to @a result, if the
/// input holds them in one block; false (with nothing read) otherwise
template<typename NumberType>
bool append_from_block(const NumberType len, string_t& result, std::true_type /*block*/)
{
if (len <= 0)
{
return false;
}
// (len > 0, so the unsigned type holds it; casting a signed char
// straight to std::size_t would trip bugprone-signed-char-misuse)
const auto ulen = static_cast<typename std::make_unsigned<NumberType>::type>(len);
const std::size_t remaining = ia.bulk_remaining();
if (static_cast<std::uintmax_t>(ulen) > static_cast<std::uintmax_t>(remaining))
{
return false; // (the loop reports the premature end)
}
const auto n = static_cast<std::size_t>(ulen);
result.append(reinterpret_cast<const typename string_t::value_type*>(ia.bulk_data()), n);
ia.bulk_skip(n);
chars_read += n;
return true;
}
template<typename NumberType, typename ContainerType>
static bool append_from_block(const NumberType /*len*/, ContainerType& /*result*/, std::false_type /*block*/) noexcept
{
return false;
}
/*!
@param[in] context further context information (for diagnostics)
@return whether the last read character is not EOF
include/nlohmann/detail/input/contiguous_parser.hpp
+137 -131
View File
@@ -37,8 +37,8 @@ namespace detail
@brief a parser for JSON text in one contiguous block, for parse(), accept(),
and sax_parse()
The parser and the lexer exchange one token at a time, and the lexer keeps its
state (the current character, a pending unget, where the token starts) in
The default parser and lexer exchange one token at a time, and the lexer keeps
its state (the current character, a pending unget, where the token starts) in
members, which every character pays for. This parser reads the block through a
local pointer instead, and the grammar, the whitespace and the tokens are one
loop, after yyjson's reader: the state stays in registers, and the expected
@@ -46,13 +46,13 @@ next token is tested where it is expected instead of being dispatched on.
It reports what it reads to a SAX handler: the one parse() uses to build the
value, the one accept() uses, or the user's handler of sax_parse(). On a byte
the library parser would reject, it stops before reporting the token, and
returns false: the events up to there are those the library parser reports.
The caller then runs the library parser on the same input to report the error
the default parser would reject, it stops before reporting the token, and
returns false: the events up to there are those the default parser reports.
The caller then runs the default parser on the same input to report the error
with its exact message and position (report_contiguous_error(),
json_sax_error_forwarder), and parse() builds no value from what was read.
What is accepted, and the values reported, are those of the library parser
What is accepted, and the values reported, are those of the default parser
with default options: the same number grammar and conversions, the same UTF-8
and escape rules, a UTF-8 byte order mark at the start, and, without
JSON_STRICT_NUL_HANDLING, a NUL byte as the end of the input.
@@ -106,28 +106,28 @@ class contiguous_parser
std::vector<std::uint64_t> outer;
// the current byte, or 0 at the end (no JSON token starts with 0)
#define JSON_CONTIGUOUS_CUR() (p != e ? *p : 0)
#define JSON_CONTIGUOUS_CUR() current(p, e)
// skip whitespace; most tokens have none before them
#define JSON_CONTIGUOUS_WS() \
do \
{ \
if (JSON_HEDLEY_UNLIKELY(JSON_CONTIGUOUS_CUR() <= ' ')) \
{ \
p = skip_whitespace(p, e); \
} \
} \
#define JSON_CONTIGUOUS_WS() \
do \
{ \
if (JSON_HEDLEY_UNLIKELY(JSON_CONTIGUOUS_CUR() <= ' ')) \
{ \
p = skip_whitespace(p, e); \
} \
} \
while (false)
#define JSON_CONTIGUOUS_OPEN(is_object) \
do \
{ \
#define JSON_CONTIGUOUS_OPEN(is_object) \
do \
{ \
if (JSON_HEDLEY_UNLIKELY(depth != 0 && (depth % 64) == 0)) /* NOLINT(readability/braces) */ \
{ \
outer.push_back(kinds); \
kinds = 0; \
} \
kinds = (kinds << 1u) | static_cast<std::uint64_t>(is_object); \
++depth; \
} \
{ \
outer.push_back(kinds); \
kinds = 0; \
} \
kinds = (kinds << 1u) | static_cast<std::uint64_t>(is_object); \
++depth; \
} \
while (false)
JSON_CONTIGUOUS_WS();
@@ -160,107 +160,107 @@ class contiguous_parser
// a value in an array or an object: expanded once for each, so that
// each dispatch has its own branch history (arrays tend to hold values
// of one kind) and the code after a scalar knows where it is
#define JSON_CONTIGUOUS_VALUE \
switch (JSON_CONTIGUOUS_CUR()) \
{ \
case '"': \
if (JSON_HEDLEY_UNLIKELY(!string(p, false))) \
{ \
return false; \
} \
break; \
case '{': \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->start_object(detail::unknown_size())))) \
{ \
return false; \
} \
JSON_CONTIGUOUS_OPEN(1u); \
goto object_first; \
case '[': \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->start_array(detail::unknown_size())))) \
{ \
return false; \
} \
JSON_CONTIGUOUS_OPEN(0u); \
goto array_first; \
case '-': \
case '0': \
case '1': \
case '2': \
case '3': \
case '4': \
case '5': \
case '6': \
case '7': \
case '8': \
case '9': \
if (JSON_HEDLEY_UNLIKELY(!number(p))) \
{ \
return false; \
} \
break; \
case 't': \
if (JSON_HEDLEY_UNLIKELY(!literal(p, "true") || !report(sax->boolean(true)))) \
{ \
return false; \
} \
break; \
case 'f': \
if (JSON_HEDLEY_UNLIKELY(!literal(p, "false") || !report(sax->boolean(false)))) \
{ \
return false; \
} \
break; \
case 'n': \
if (JSON_HEDLEY_UNLIKELY(!literal(p, "null") || !report(sax->null()))) \
{ \
return false; \
} \
break; \
default: \
return false; \
#define JSON_CONTIGUOUS_VALUE \
switch (JSON_CONTIGUOUS_CUR()) \
{ \
case '"': \
if (JSON_HEDLEY_UNLIKELY(!string(p, false))) \
{ \
return false; \
} \
break; \
case '{': \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->start_object(detail::unknown_size())))) \
{ \
return false; \
} \
JSON_CONTIGUOUS_OPEN(1u); \
goto object_first; \
case '[': \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->start_array(detail::unknown_size())))) \
{ \
return false; \
} \
JSON_CONTIGUOUS_OPEN(0u); \
goto array_first; \
case '-': \
case '0': \
case '1': \
case '2': \
case '3': \
case '4': \
case '5': \
case '6': \
case '7': \
case '8': \
case '9': \
if (JSON_HEDLEY_UNLIKELY(!number(p))) \
{ \
return false; \
} \
break; \
case 't': \
if (JSON_HEDLEY_UNLIKELY(!literal(p, "true") || !report(sax->boolean(true)))) \
{ \
return false; \
} \
break; \
case 'f': \
if (JSON_HEDLEY_UNLIKELY(!literal(p, "false") || !report(sax->boolean(false)))) \
{ \
return false; \
} \
break; \
case 'n': \
if (JSON_HEDLEY_UNLIKELY(!literal(p, "null") || !report(sax->null()))) \
{ \
return false; \
} \
break; \
default: \
return false; \
}
// what may follow a value in an array: a comma and the next value, or the end
#define JSON_CONTIGUOUS_AFTER_ELEMENT \
JSON_CONTIGUOUS_WS(); \
#define JSON_CONTIGUOUS_AFTER_ELEMENT \
JSON_CONTIGUOUS_WS(); \
if (JSON_HEDLEY_LIKELY(JSON_CONTIGUOUS_CUR() == ',')) /* NOLINT(readability/braces) */ \
{ \
++p; \
JSON_CONTIGUOUS_WS(); \
goto array_value; \
} \
{ \
++p; \
JSON_CONTIGUOUS_WS(); \
goto array_value; \
} \
if (JSON_HEDLEY_LIKELY(JSON_CONTIGUOUS_CUR() == ']')) /* NOLINT(readability/braces) */ \
{ \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->end_array()))) \
{ \
return false; \
} \
goto close; \
} \
{ \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->end_array()))) \
{ \
return false; \
} \
goto close; \
} \
return false;
// what may follow a value in an object: a comma and the next member, or the end
#define JSON_CONTIGUOUS_AFTER_MEMBER \
JSON_CONTIGUOUS_WS(); \
#define JSON_CONTIGUOUS_AFTER_MEMBER \
JSON_CONTIGUOUS_WS(); \
if (JSON_HEDLEY_LIKELY(JSON_CONTIGUOUS_CUR() == ',')) /* NOLINT(readability/braces) */ \
{ \
++p; \
JSON_CONTIGUOUS_WS(); \
goto object_key; \
} \
{ \
++p; \
JSON_CONTIGUOUS_WS(); \
goto object_key; \
} \
if (JSON_HEDLEY_LIKELY(JSON_CONTIGUOUS_CUR() == '}')) /* NOLINT(readability/braces) */ \
{ \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->end_object()))) \
{ \
return false; \
} \
goto close; \
} \
{ \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->end_object()))) \
{ \
return false; \
} \
goto close; \
} \
return false;
array_first:
@@ -387,6 +387,12 @@ done:
return KeepValues;
}
/// the byte at @a p, or 0 at the end @a e (no JSON token starts with 0)
static JSON_HEDLEY_ALWAYS_INLINE uchar current(const uchar* p, const uchar* e) noexcept
{
return p != e ? *p : 0;
}
/// the first byte at or after p that is not whitespace, or e
static JSON_HEDLEY_NEVER_INLINE const uchar* skip_whitespace(const uchar* p, const uchar* e) noexcept
{
@@ -436,7 +442,7 @@ done:
/// a JSON text that is a single scalar
bool scalar(const uchar*& p)
{
switch (p != end ? *p : 0)
switch (current(p, end))
{
case '"':
return string(p, false);
@@ -624,7 +630,7 @@ done:
contiguous path (lexer::scan_number_bulk_contiguous())
Integers that do not fit their type become floats; floats that overflow
are an error, which the library parser reports.
are an error, which the default parser reports.
*/
JSON_HEDLEY_ALWAYS_INLINE bool number(const uchar*& pos)
{
@@ -773,7 +779,7 @@ done:
}
if (JSON_HEDLEY_UNLIKELY(!std::isfinite(value)))
{
return false; // the library parser reports the overflow
return false; // the default parser reports the overflow
}
return report(sax->number_float(value, number_text(data, data + i)));
}
@@ -811,7 +817,7 @@ struct can_parse_contiguous
@brief report the input behind @a adapter, one block of memory, to @a sax
@return whether the input is valid and was reported completely; if not,
nothing was consumed from @a adapter, and the caller has the library
nothing was consumed from @a adapter, and the caller has the default
parser report the error
*/
template<typename BasicJsonType, bool KeepValues, typename SAX, typename InputAdapterType>
@@ -820,7 +826,7 @@ bool parse_contiguous(InputAdapterType& adapter, SAX& sax, std::true_type /*cont
const std::size_t size = adapter.bulk_remaining();
if (size == 0)
{
return false; // the library parser reports the empty input
return false; // the default parser reports the empty input
}
const auto* const first = reinterpret_cast<const unsigned char*>(adapter.bulk_data());
contiguous_parser<BasicJsonType, SAX, KeepValues> p(first, first + size, &sax);
@@ -831,7 +837,7 @@ bool parse_contiguous(InputAdapterType& adapter, SAX& sax, std::true_type /*cont
@brief a SAX handler that only reports a parse error, as the handler of parse()
does: it throws the exception, unless exceptions are not allowed
After contiguous_parser has rejected an input, the library parser is run again
After contiguous_parser has rejected an input, the default parser is run again
with this handler to report the error: the error, its message and its position
are those of parse(), without building the values read up to it.
*/
@@ -868,7 +874,7 @@ struct sax_ignores_number_text<json_sax_error_reporter<BasicJsonType>> : std::tr
rejected, as parse() reports it: throw its exception, or, without
exceptions, return true
@return false if the library parser accepts the input after all (which would
@return false if the default parser accepts the input after all (which would
be a disagreement of the two parsers): the caller then parses it
*/
template<typename BasicJsonType, typename InputAdapterType>
@@ -922,7 +928,7 @@ bool parse_contiguous(InputAdapterType& /*adapter*/, BasicJsonType& /*result*/,
@return whether @a accepted is the result of accept(); false if the input is
not one block of memory, in which case the caller checks it.
contiguous_parser accepts exactly what the library parser accepts.
contiguous_parser accepts exactly what the default parser accepts.
*/
template<typename BasicJsonType, typename InputAdapterType>
bool accept_contiguous(InputAdapterType& adapter, bool& accepted, std::true_type /*contiguous*/)
@@ -943,9 +949,9 @@ bool accept_contiguous(InputAdapterType& /*adapter*/, bool& /*accepted*/, std::f
handler of the user
After contiguous_parser has delivered the events of the input to the user's
handler and rejected it, the library parser is run again with this handler:
handler and rejected it, the default parser is run again with this handler:
the user's handler gets the error, its message and its position from the
library parser, as before, but no event twice.
default parser, as before, but no event twice.
*/
template<typename BasicJsonType, typename SAX>
class json_sax_error_forwarder : public json_sax_acceptor<BasicJsonType>
@@ -962,7 +968,7 @@ class json_sax_error_forwarder : public json_sax_acceptor<BasicJsonType>
return user->parse_error(position, last_token, ex);
}
/// whether the library parser reported an error
/// whether the default parser reported an error
bool reported() const noexcept
{
return forwarded;
@@ -981,8 +987,8 @@ struct sax_ignores_number_text<json_sax_error_forwarder<BasicJsonType, SAX>> : s
a user's handler @a sax
contiguous_parser reports to @a sax what it reads, and stops at the token that
the library parser would reject, before reporting it: the events up to an error
are the same. The error itself is then reported by the library parser (see
the default parser would reject, before reporting it: the events up to an error
are the same. The error itself is then reported by the default parser (see
json_sax_error_forwarder).
@return whether @a result is the result of sax_parse(); false if the input is
@@ -1003,14 +1009,14 @@ bool sax_parse_contiguous(InputAdapterType& adapter, SAX* sax, bool& result, std
}
if (p.aborted())
{
// the handler returned false, as with the library parser
// the handler returned false, as with the default parser
result = false;
return true;
}
}
json_sax_error_forwarder<BasicJsonType, SAX> forwarder(sax);
result = parser<BasicJsonType, InputAdapterType>(InputAdapterType(adapter), nullptr, true, false, false).sax_parse(&forwarder, true);
// the library parser must reject the input as well (the events after the
// the default parser must reject the input as well (the events after the
// byte contiguous_parser stopped at cannot be delivered any more)
JSON_ASSERT(forwarder.reported());
return true;
include/nlohmann/detail/input/input_adapters.hpp
+177 -2
View File
@@ -58,6 +58,19 @@
#define JSON_UNLOCKED_FILE_IO 0
#endif
#undef JSON_UNLOCKED_FILE_IO_MSAN
// Whether file_input_adapter scans the buffer of the FILE directly, as
// getc_unlocked() reads it: the fields it uses are those that the C
// library's own getc_unlocked() macro uses (glibc: _IO_read_ptr and
// _IO_read_end; Apple: _p and _r). It needs the file locked for the whole
// parse, as JSON_UNLOCKED_FILE_IO == 1 has it (so JSON_DISABLE_UNLOCKED_FILE_IO
// and MemorySanitizer builds turn it off).
// (uClibc defines __GLIBC__ as well, but its FILE has other fields)
#if JSON_UNLOCKED_FILE_IO == 1 && ((defined(__GLIBC__) && !defined(__UCLIBC__)) || defined(__APPLE__))
#define JSON_FILE_WINDOW 1
#else
#define JSON_FILE_WINDOW 0
#endif
#endif // JSON_NO_IO
NLOHMANN_JSON_NAMESPACE_BEGIN
@@ -179,8 +192,12 @@ class token_carry_buffer
char* m_capacity_end = nullptr;
};
/*!
Input adapter for stdio file access. This adapter read only 1 byte and do not use any
buffer. This adapter is a very low level adapter.
Input adapter for stdio file access. The file is locked for the lifetime of the
adapter and read with the unlocked stdio functions (see
JSON_DISABLE_UNLOCKED_FILE_IO). With glibc and the Apple C library, the
characters in the buffer of the FILE are also scanned in bulk, as the get area
of a stream is (see input_stream_adapter): exactly the characters getc_unlocked()
would return are consumed, so the file is left where it was left before.
*/
class file_input_adapter
{
@@ -199,6 +216,12 @@ class file_input_adapter
file_input_adapter(const file_input_adapter&) = delete;
file_input_adapter(file_input_adapter&& rhs) noexcept
: m_file(rhs.m_file)
#if JSON_FILE_WINDOW
, token_carry(std::move(rhs.token_carry))
, token_segment(rhs.token_segment)
, current_in_buffer(rhs.current_in_buffer)
, tracking_token(rhs.tracking_token)
#endif
{
// the lock is owned by the thread, not the adapter: hand it over
rhs.m_file = nullptr;
@@ -210,6 +233,20 @@ class file_input_adapter
unlock();
}
#if JSON_FILE_WINDOW
std::char_traits<char>::int_type get_character()
{
// what getc_unlocked() does, while the buffer has characters
const char* const next = buffer_ptr();
if (JSON_HEDLEY_LIKELY(next != buffer_end()))
{
current_in_buffer = true;
buffer_bump(1);
return std::char_traits<char>::to_int_type(*next);
}
return get_character_slow();
}
#else
std::char_traits<char>::int_type get_character() noexcept
{
// the file is locked for the lifetime of the adapter, so the
@@ -222,6 +259,7 @@ class file_input_adapter
return std::fgetc(m_file);
#endif
}
#endif
// returns the number of characters successfully read
template<class T>
@@ -230,7 +268,134 @@ class file_input_adapter
return fread(dest, 1, sizeof(T) * count, m_file);
}
#if JSON_FILE_WINDOW
// The lexer may scan the buffer of the FILE directly, as the window of
// input_stream_adapter: the buffer ends wherever the C library's buffer
// ends, and is refilled by the next get_character().
static constexpr bool supports_bulk_scan = true;
static constexpr bool bulk_window = true;
// Pointer to the next unread character; only valid when bulk_remaining() > 0.
const char* bulk_data() const
{
return buffer_ptr();
}
// Number of unread characters in the buffer.
std::size_t bulk_remaining() const
{
if (!current_in_buffer)
{
return 0;
}
return static_cast<std::size_t>(buffer_end() - buffer_ptr());
}
// Consume @a n characters previously inspected via bulk_data().
void bulk_skip(std::size_t n)
{
JSON_ASSERT(n <= bulk_remaining());
buffer_bump(n);
}
// The adapter keeps the current token for the lexer's error messages, as
// input_stream_adapter does.
static constexpr bool supports_token_tracking = true;
void begin_token() noexcept
{
tracking_token = true;
token_carry.clear();
token_segment = buffer_ptr();
}
void mark_token_start(std::char_traits<char>::int_type c)
{
tracking_token = true;
token_carry.clear();
if (current_in_buffer)
{
token_segment = buffer_ptr() - 1;
}
else
{
token_segment = nullptr;
token_carry.push_back(std::char_traits<char>::to_char_type(c));
}
}
void copy_token(std::vector<char>& out, bool drop_last) const
{
token_carry.copy_to(out);
if (token_segment != nullptr)
{
out.insert(out.end(), token_segment, buffer_ptr());
}
if (drop_last && !out.empty())
{
out.pop_back();
}
}
#endif
private:
#if JSON_FILE_WINDOW
// the buffer of the FILE: [buffer_ptr(), buffer_end()) are the characters
// getc_unlocked() would return next
#if defined(__GLIBC__)
const char* buffer_ptr() const noexcept
{
return m_file->_IO_read_ptr;
}
const char* buffer_end() const noexcept
{
return m_file->_IO_read_end;
}
void buffer_bump(std::size_t n) noexcept
{
m_file->_IO_read_ptr += n;
}
#else
const char* buffer_ptr() const noexcept
{
return reinterpret_cast<const char*>(m_file->_p);
}
const char* buffer_end() const noexcept
{
return m_file->_r > 0 ? reinterpret_cast<const char*>(m_file->_p) + m_file->_r : reinterpret_cast<const char*>(m_file->_p);
}
void buffer_bump(std::size_t n) noexcept
{
m_file->_p += n;
m_file->_r -= static_cast<int>(n);
}
#endif
// the buffer is exhausted: getc_unlocked() refills it
JSON_HEDLEY_NEVER_INLINE std::char_traits<char>::int_type get_character_slow()
{
if (token_segment != nullptr)
{
token_carry.append(token_segment, buffer_end());
token_segment = nullptr;
}
const auto res = getc_unlocked(m_file);
if (res == EOF)
{
current_in_buffer = false;
return std::char_traits<char>::eof();
}
// the character was taken from the refilled buffer, at buffer_ptr() - 1
current_in_buffer = true;
if (tracking_token)
{
token_segment = buffer_ptr() - 1;
}
return res;
}
#endif
// Lock the file once for the whole parse instead of once per character.
// The lock is recursive, so fread() and the user's own stdio calls on the
// same thread keep working.
@@ -259,6 +424,16 @@ class file_input_adapter
/// the file pointer to read from
std::FILE* m_file;
#if JSON_FILE_WINDOW
/// the part of the current token that was in earlier buffers
token_carry_buffer token_carry{}; // NOLINT(readability-redundant-member-init)
/// start of the current token's part in the buffer, or nullptr
const char* token_segment = nullptr;
/// whether the character last returned by get_character() is in the buffer
bool current_in_buffer = false;
/// whether a token is tracked at all; the binary readers never start one
bool tracking_token = false;
#endif
};
/*!
include/nlohmann/detail/macro_unscope.hpp
+1
View File
@@ -22,6 +22,7 @@
#undef JSON_DISABLE_ENUM_SERIALIZATION
#undef JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
#undef JSON_UNLOCKED_FILE_IO
#undef JSON_FILE_WINDOW
#undef JSON_DTOA_SSE2
#undef JSON_DTOA_NEON
#undef JSON_LITTLE_ENDIAN_TARGET
include/nlohmann/json.hpp
+6 -5
View File
@@ -3111,7 +3111,7 @@ public:
{
basic_json result;
// JSON in one block of memory, with the default options, is read by
// the faster contiguous_parser; on an error, the library parser reads
// the faster contiguous_parser; on an error, the default parser reads
// it again to report it (see contiguous_parser)
using contiguous = std::integral_constant<bool, detail::can_parse_contiguous<basic_json, typename std::decay<InputAdapterType>::type>::value>;
if (cb == nullptr && !ignore_comments && !ignore_trailing_commas
@@ -3129,8 +3129,8 @@ public:
const bool ignore_comments,
const bool ignore_trailing_commas)
{
// JSON in one block of memory is checked by the faster
// contiguous_parser (see parse_impl())
// JSON in one block of memory, with the default options, is checked by
// the faster contiguous_parser (see parse_impl())
using adapter_t = typename std::decay<InputAdapterType>::type;
bool accepted = false;
if (!ignore_comments && !ignore_trailing_commas
@@ -3154,8 +3154,9 @@ public:
{
if (format == input_format_t::json)
{
// JSON in one block of memory is read by the faster
// contiguous_parser, with the default options (see parse_impl())
// JSON in one block of memory, with the default options, is read by
// the faster contiguous_parser; on an error, the default parser
// reads it again to report it (see parse_impl())
bool result = false;
if (strict && !ignore_comments && !ignore_trailing_commas
&& detail::sax_parse_contiguous<basic_json>(ia, sax, result, std::integral_constant<bool, detail::can_parse_contiguous<basic_json, InputAdapterType>::value> {}))
single_include/nlohmann/json.hpp
Generated
+359 -138
View File
@@ -9167,6 +9167,19 @@ NLOHMANN_JSON_NAMESPACE_END
#define JSON_UNLOCKED_FILE_IO 0
#endif
#undef JSON_UNLOCKED_FILE_IO_MSAN
// Whether file_input_adapter scans the buffer of the FILE directly, as
// getc_unlocked() reads it: the fields it uses are those that the C
// library's own getc_unlocked() macro uses (glibc: _IO_read_ptr and
// _IO_read_end; Apple: _p and _r). It needs the file locked for the whole
// parse, as JSON_UNLOCKED_FILE_IO == 1 has it (so JSON_DISABLE_UNLOCKED_FILE_IO
// and MemorySanitizer builds turn it off).
// (uClibc defines __GLIBC__ as well, but its FILE has other fields)
#if JSON_UNLOCKED_FILE_IO == 1 && ((defined(__GLIBC__) && !defined(__UCLIBC__)) || defined(__APPLE__))
#define JSON_FILE_WINDOW 1
#else
#define JSON_FILE_WINDOW 0
#endif
#endif // JSON_NO_IO
NLOHMANN_JSON_NAMESPACE_BEGIN
@@ -9288,8 +9301,12 @@ class token_carry_buffer
char* m_capacity_end = nullptr;
};
/*!
Input adapter for stdio file access. This adapter read only 1 byte and do not use any
buffer. This adapter is a very low level adapter.
Input adapter for stdio file access. The file is locked for the lifetime of the
adapter and read with the unlocked stdio functions (see
JSON_DISABLE_UNLOCKED_FILE_IO). With glibc and the Apple C library, the
characters in the buffer of the FILE are also scanned in bulk, as the get area
of a stream is (see input_stream_adapter): exactly the characters getc_unlocked()
would return are consumed, so the file is left where it was left before.
*/
class file_input_adapter
{
@@ -9308,6 +9325,12 @@ class file_input_adapter
file_input_adapter(const file_input_adapter&) = delete;
file_input_adapter(file_input_adapter&& rhs) noexcept
: m_file(rhs.m_file)
#if JSON_FILE_WINDOW
, token_carry(std::move(rhs.token_carry))
, token_segment(rhs.token_segment)
, current_in_buffer(rhs.current_in_buffer)
, tracking_token(rhs.tracking_token)
#endif
{
// the lock is owned by the thread, not the adapter: hand it over
rhs.m_file = nullptr;
@@ -9319,6 +9342,20 @@ class file_input_adapter
unlock();
}
#if JSON_FILE_WINDOW
std::char_traits<char>::int_type get_character()
{
// what getc_unlocked() does, while the buffer has characters
const char* const next = buffer_ptr();
if (JSON_HEDLEY_LIKELY(next != buffer_end()))
{
current_in_buffer = true;
buffer_bump(1);
return std::char_traits<char>::to_int_type(*next);
}
return get_character_slow();
}
#else
std::char_traits<char>::int_type get_character() noexcept
{
// the file is locked for the lifetime of the adapter, so the
@@ -9331,6 +9368,7 @@ class file_input_adapter
return std::fgetc(m_file);
#endif
}
#endif
// returns the number of characters successfully read
template<class T>
@@ -9339,7 +9377,134 @@ class file_input_adapter
return fread(dest, 1, sizeof(T) * count, m_file);
}
#if JSON_FILE_WINDOW
// The lexer may scan the buffer of the FILE directly, as the window of
// input_stream_adapter: the buffer ends wherever the C library's buffer
// ends, and is refilled by the next get_character().
static constexpr bool supports_bulk_scan = true;
static constexpr bool bulk_window = true;
// Pointer to the next unread character; only valid when bulk_remaining() > 0.
const char* bulk_data() const
{
return buffer_ptr();
}
// Number of unread characters in the buffer.
std::size_t bulk_remaining() const
{
if (!current_in_buffer)
{
return 0;
}
return static_cast<std::size_t>(buffer_end() - buffer_ptr());
}
// Consume @a n characters previously inspected via bulk_data().
void bulk_skip(std::size_t n)
{
JSON_ASSERT(n <= bulk_remaining());
buffer_bump(n);
}
// The adapter keeps the current token for the lexer's error messages, as
// input_stream_adapter does.
static constexpr bool supports_token_tracking = true;
void begin_token() noexcept
{
tracking_token = true;
token_carry.clear();
token_segment = buffer_ptr();
}
void mark_token_start(std::char_traits<char>::int_type c)
{
tracking_token = true;
token_carry.clear();
if (current_in_buffer)
{
token_segment = buffer_ptr() - 1;
}
else
{
token_segment = nullptr;
token_carry.push_back(std::char_traits<char>::to_char_type(c));
}
}
void copy_token(std::vector<char>& out, bool drop_last) const
{
token_carry.copy_to(out);
if (token_segment != nullptr)
{
out.insert(out.end(), token_segment, buffer_ptr());
}
if (drop_last && !out.empty())
{
out.pop_back();
}
}
#endif
private:
#if JSON_FILE_WINDOW
// the buffer of the FILE: [buffer_ptr(), buffer_end()) are the characters
// getc_unlocked() would return next
#if defined(__GLIBC__)
const char* buffer_ptr() const noexcept
{
return m_file->_IO_read_ptr;
}
const char* buffer_end() const noexcept
{
return m_file->_IO_read_end;
}
void buffer_bump(std::size_t n) noexcept
{
m_file->_IO_read_ptr += n;
}
#else
const char* buffer_ptr() const noexcept
{
return reinterpret_cast<const char*>(m_file->_p);
}
const char* buffer_end() const noexcept
{
return m_file->_r > 0 ? reinterpret_cast<const char*>(m_file->_p) + m_file->_r : reinterpret_cast<const char*>(m_file->_p);
}
void buffer_bump(std::size_t n) noexcept
{
m_file->_p += n;
m_file->_r -= static_cast<int>(n);
}
#endif
// the buffer is exhausted: getc_unlocked() refills it
JSON_HEDLEY_NEVER_INLINE std::char_traits<char>::int_type get_character_slow()
{
if (token_segment != nullptr)
{
token_carry.append(token_segment, buffer_end());
token_segment = nullptr;
}
const auto res = getc_unlocked(m_file);
if (res == EOF)
{
current_in_buffer = false;
return std::char_traits<char>::eof();
}
// the character was taken from the refilled buffer, at buffer_ptr() - 1
current_in_buffer = true;
if (tracking_token)
{
token_segment = buffer_ptr() - 1;
}
return res;
}
#endif
// Lock the file once for the whole parse instead of once per character.
// The lock is recursive, so fread() and the user's own stdio calls on the
// same thread keep working.
@@ -9368,6 +9533,16 @@ class file_input_adapter
/// the file pointer to read from
std::FILE* m_file;
#if JSON_FILE_WINDOW
/// the part of the current token that was in earlier buffers
token_carry_buffer token_carry{}; // NOLINT(readability-redundant-member-init)
/// start of the current token's part in the buffer, or nullptr
const char* token_segment = nullptr;
/// whether the character last returned by get_character() is in the buffer
bool current_in_buffer = false;
/// whether a token is tracked at all; the binary readers never start one
bool tracking_token = false;
#endif
};
/*!
@@ -22933,6 +23108,14 @@ class binary_reader
const char* context,
ContainerType& result)
{
// a string that is in the block of input as a whole is appended from
// it, without the zero-filling resize() below
constexpr bool from_block = bulk_scan && std::is_same<ContainerType, string_t>::value;
if (append_from_block(len, result, std::integral_constant<bool, from_block> {}))
{
return true;
}
// upper bound on the number of bytes read (and allocated) per chunk
constexpr std::size_t chunk_size = 4096;
@@ -22969,6 +23152,36 @@ class binary_reader
return true;
}
/// append the @a len bytes at the current position to @a result, if the
/// input holds them in one block; false (with nothing read) otherwise
template<typename NumberType>
bool append_from_block(const NumberType len, string_t& result, std::true_type /*block*/)
{
if (len <= 0)
{
return false;
}
// (len > 0, so the unsigned type holds it; casting a signed char
// straight to std::size_t would trip bugprone-signed-char-misuse)
const auto ulen = static_cast<typename std::make_unsigned<NumberType>::type>(len);
const std::size_t remaining = ia.bulk_remaining();
if (static_cast<std::uintmax_t>(ulen) > static_cast<std::uintmax_t>(remaining))
{
return false; // (the loop reports the premature end)
}
const auto n = static_cast<std::size_t>(ulen);
result.append(reinterpret_cast<const typename string_t::value_type*>(ia.bulk_data()), n);
ia.bulk_skip(n);
chars_read += n;
return true;
}
template<typename NumberType, typename ContainerType>
static bool append_from_block(const NumberType /*len*/, ContainerType& /*result*/, std::false_type /*block*/) noexcept
{
return false;
}
/*!
@param[in] context further context information (for diagnostics)
@return whether the last read character is not EOF
@@ -23906,8 +24119,8 @@ namespace detail
@brief a parser for JSON text in one contiguous block, for parse(), accept(),
and sax_parse()
The parser and the lexer exchange one token at a time, and the lexer keeps its
state (the current character, a pending unget, where the token starts) in
The default parser and lexer exchange one token at a time, and the lexer keeps
its state (the current character, a pending unget, where the token starts) in
members, which every character pays for. This parser reads the block through a
local pointer instead, and the grammar, the whitespace and the tokens are one
loop, after yyjson's reader: the state stays in registers, and the expected
@@ -23915,13 +24128,13 @@ next token is tested where it is expected instead of being dispatched on.
It reports what it reads to a SAX handler: the one parse() uses to build the
value, the one accept() uses, or the user's handler of sax_parse(). On a byte
the library parser would reject, it stops before reporting the token, and
returns false: the events up to there are those the library parser reports.
The caller then runs the library parser on the same input to report the error
the default parser would reject, it stops before reporting the token, and
returns false: the events up to there are those the default parser reports.
The caller then runs the default parser on the same input to report the error
with its exact message and position (report_contiguous_error(),
json_sax_error_forwarder), and parse() builds no value from what was read.
What is accepted, and the values reported, are those of the library parser
What is accepted, and the values reported, are those of the default parser
with default options: the same number grammar and conversions, the same UTF-8
and escape rules, a UTF-8 byte order mark at the start, and, without
JSON_STRICT_NUL_HANDLING, a NUL byte as the end of the input.
@@ -23975,28 +24188,28 @@ class contiguous_parser
std::vector<std::uint64_t> outer;
// the current byte, or 0 at the end (no JSON token starts with 0)
#define JSON_CONTIGUOUS_CUR() (p != e ? *p : 0)
#define JSON_CONTIGUOUS_CUR() current(p, e)
// skip whitespace; most tokens have none before them
#define JSON_CONTIGUOUS_WS() \
do \
{ \
if (JSON_HEDLEY_UNLIKELY(JSON_CONTIGUOUS_CUR() <= ' ')) \
{ \
p = skip_whitespace(p, e); \
} \
} \
#define JSON_CONTIGUOUS_WS() \
do \
{ \
if (JSON_HEDLEY_UNLIKELY(JSON_CONTIGUOUS_CUR() <= ' ')) \
{ \
p = skip_whitespace(p, e); \
} \
} \
while (false)
#define JSON_CONTIGUOUS_OPEN(is_object) \
do \
{ \
#define JSON_CONTIGUOUS_OPEN(is_object) \
do \
{ \
if (JSON_HEDLEY_UNLIKELY(depth != 0 && (depth % 64) == 0)) /* NOLINT(readability/braces) */ \
{ \
outer.push_back(kinds); \
kinds = 0; \
} \
kinds = (kinds << 1u) | static_cast<std::uint64_t>(is_object); \
++depth; \
} \
{ \
outer.push_back(kinds); \
kinds = 0; \
} \
kinds = (kinds << 1u) | static_cast<std::uint64_t>(is_object); \
++depth; \
} \
while (false)
JSON_CONTIGUOUS_WS();
@@ -24029,107 +24242,107 @@ class contiguous_parser
// a value in an array or an object: expanded once for each, so that
// each dispatch has its own branch history (arrays tend to hold values
// of one kind) and the code after a scalar knows where it is
#define JSON_CONTIGUOUS_VALUE \
switch (JSON_CONTIGUOUS_CUR()) \
{ \
case '"': \
if (JSON_HEDLEY_UNLIKELY(!string(p, false))) \
{ \
return false; \
} \
break; \
case '{': \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->start_object(detail::unknown_size())))) \
{ \
return false; \
} \
JSON_CONTIGUOUS_OPEN(1u); \
goto object_first; \
case '[': \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->start_array(detail::unknown_size())))) \
{ \
return false; \
} \
JSON_CONTIGUOUS_OPEN(0u); \
goto array_first; \
case '-': \
case '0': \
case '1': \
case '2': \
case '3': \
case '4': \
case '5': \
case '6': \
case '7': \
case '8': \
case '9': \
if (JSON_HEDLEY_UNLIKELY(!number(p))) \
{ \
return false; \
} \
break; \
case 't': \
if (JSON_HEDLEY_UNLIKELY(!literal(p, "true") || !report(sax->boolean(true)))) \
{ \
return false; \
} \
break; \
case 'f': \
if (JSON_HEDLEY_UNLIKELY(!literal(p, "false") || !report(sax->boolean(false)))) \
{ \
return false; \
} \
break; \
case 'n': \
if (JSON_HEDLEY_UNLIKELY(!literal(p, "null") || !report(sax->null()))) \
{ \
return false; \
} \
break; \
default: \
return false; \
#define JSON_CONTIGUOUS_VALUE \
switch (JSON_CONTIGUOUS_CUR()) \
{ \
case '"': \
if (JSON_HEDLEY_UNLIKELY(!string(p, false))) \
{ \
return false; \
} \
break; \
case '{': \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->start_object(detail::unknown_size())))) \
{ \
return false; \
} \
JSON_CONTIGUOUS_OPEN(1u); \
goto object_first; \
case '[': \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->start_array(detail::unknown_size())))) \
{ \
return false; \
} \
JSON_CONTIGUOUS_OPEN(0u); \
goto array_first; \
case '-': \
case '0': \
case '1': \
case '2': \
case '3': \
case '4': \
case '5': \
case '6': \
case '7': \
case '8': \
case '9': \
if (JSON_HEDLEY_UNLIKELY(!number(p))) \
{ \
return false; \
} \
break; \
case 't': \
if (JSON_HEDLEY_UNLIKELY(!literal(p, "true") || !report(sax->boolean(true)))) \
{ \
return false; \
} \
break; \
case 'f': \
if (JSON_HEDLEY_UNLIKELY(!literal(p, "false") || !report(sax->boolean(false)))) \
{ \
return false; \
} \
break; \
case 'n': \
if (JSON_HEDLEY_UNLIKELY(!literal(p, "null") || !report(sax->null()))) \
{ \
return false; \
} \
break; \
default: \
return false; \
}
// what may follow a value in an array: a comma and the next value, or the end
#define JSON_CONTIGUOUS_AFTER_ELEMENT \
JSON_CONTIGUOUS_WS(); \
#define JSON_CONTIGUOUS_AFTER_ELEMENT \
JSON_CONTIGUOUS_WS(); \
if (JSON_HEDLEY_LIKELY(JSON_CONTIGUOUS_CUR() == ',')) /* NOLINT(readability/braces) */ \
{ \
++p; \
JSON_CONTIGUOUS_WS(); \
goto array_value; \
} \
{ \
++p; \
JSON_CONTIGUOUS_WS(); \
goto array_value; \
} \
if (JSON_HEDLEY_LIKELY(JSON_CONTIGUOUS_CUR() == ']')) /* NOLINT(readability/braces) */ \
{ \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->end_array()))) \
{ \
return false; \
} \
goto close; \
} \
{ \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->end_array()))) \
{ \
return false; \
} \
goto close; \
} \
return false;
// what may follow a value in an object: a comma and the next member, or the end
#define JSON_CONTIGUOUS_AFTER_MEMBER \
JSON_CONTIGUOUS_WS(); \
#define JSON_CONTIGUOUS_AFTER_MEMBER \
JSON_CONTIGUOUS_WS(); \
if (JSON_HEDLEY_LIKELY(JSON_CONTIGUOUS_CUR() == ',')) /* NOLINT(readability/braces) */ \
{ \
++p; \
JSON_CONTIGUOUS_WS(); \
goto object_key; \
} \
{ \
++p; \
JSON_CONTIGUOUS_WS(); \
goto object_key; \
} \
if (JSON_HEDLEY_LIKELY(JSON_CONTIGUOUS_CUR() == '}')) /* NOLINT(readability/braces) */ \
{ \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->end_object()))) \
{ \
return false; \
} \
goto close; \
} \
{ \
++p; \
if (JSON_HEDLEY_UNLIKELY(!report(sax->end_object()))) \
{ \
return false; \
} \
goto close; \
} \
return false;
array_first:
@@ -24256,6 +24469,12 @@ done:
return KeepValues;
}
/// the byte at @a p, or 0 at the end @a e (no JSON token starts with 0)
static JSON_HEDLEY_ALWAYS_INLINE uchar current(const uchar* p, const uchar* e) noexcept
{
return p != e ? *p : 0;
}
/// the first byte at or after p that is not whitespace, or e
static JSON_HEDLEY_NEVER_INLINE const uchar* skip_whitespace(const uchar* p, const uchar* e) noexcept
{
@@ -24305,7 +24524,7 @@ done:
/// a JSON text that is a single scalar
bool scalar(const uchar*& p)
{
switch (p != end ? *p : 0)
switch (current(p, end))
{
case '"':
return string(p, false);
@@ -24493,7 +24712,7 @@ done:
contiguous path (lexer::scan_number_bulk_contiguous())
Integers that do not fit their type become floats; floats that overflow
are an error, which the library parser reports.
are an error, which the default parser reports.
*/
JSON_HEDLEY_ALWAYS_INLINE bool number(const uchar*& pos)
{
@@ -24642,7 +24861,7 @@ done:
}
if (JSON_HEDLEY_UNLIKELY(!std::isfinite(value)))
{
return false; // the library parser reports the overflow
return false; // the default parser reports the overflow
}
return report(sax->number_float(value, number_text(data, data + i)));
}
@@ -24680,7 +24899,7 @@ struct can_parse_contiguous
@brief report the input behind @a adapter, one block of memory, to @a sax
@return whether the input is valid and was reported completely; if not,
nothing was consumed from @a adapter, and the caller has the library
nothing was consumed from @a adapter, and the caller has the default
parser report the error
*/
template<typename BasicJsonType, bool KeepValues, typename SAX, typename InputAdapterType>
@@ -24689,7 +24908,7 @@ bool parse_contiguous(InputAdapterType& adapter, SAX& sax, std::true_type /*cont
const std::size_t size = adapter.bulk_remaining();
if (size == 0)
{
return false; // the library parser reports the empty input
return false; // the default parser reports the empty input
}
const auto* const first = reinterpret_cast<const unsigned char*>(adapter.bulk_data());
contiguous_parser<BasicJsonType, SAX, KeepValues> p(first, first + size, &sax);
@@ -24700,7 +24919,7 @@ bool parse_contiguous(InputAdapterType& adapter, SAX& sax, std::true_type /*cont
@brief a SAX handler that only reports a parse error, as the handler of parse()
does: it throws the exception, unless exceptions are not allowed
After contiguous_parser has rejected an input, the library parser is run again
After contiguous_parser has rejected an input, the default parser is run again
with this handler to report the error: the error, its message and its position
are those of parse(), without building the values read up to it.
*/
@@ -24737,7 +24956,7 @@ struct sax_ignores_number_text<json_sax_error_reporter<BasicJsonType>> : std::tr
rejected, as parse() reports it: throw its exception, or, without
exceptions, return true
@return false if the library parser accepts the input after all (which would
@return false if the default parser accepts the input after all (which would
be a disagreement of the two parsers): the caller then parses it
*/
template<typename BasicJsonType, typename InputAdapterType>
@@ -24791,7 +25010,7 @@ bool parse_contiguous(InputAdapterType& /*adapter*/, BasicJsonType& /*result*/,
@return whether @a accepted is the result of accept(); false if the input is
not one block of memory, in which case the caller checks it.
contiguous_parser accepts exactly what the library parser accepts.
contiguous_parser accepts exactly what the default parser accepts.
*/
template<typename BasicJsonType, typename InputAdapterType>
bool accept_contiguous(InputAdapterType& adapter, bool& accepted, std::true_type /*contiguous*/)
@@ -24812,9 +25031,9 @@ bool accept_contiguous(InputAdapterType& /*adapter*/, bool& /*accepted*/, std::f
handler of the user
After contiguous_parser has delivered the events of the input to the user's
handler and rejected it, the library parser is run again with this handler:
handler and rejected it, the default parser is run again with this handler:
the user's handler gets the error, its message and its position from the
library parser, as before, but no event twice.
default parser, as before, but no event twice.
*/
template<typename BasicJsonType, typename SAX>
class json_sax_error_forwarder : public json_sax_acceptor<BasicJsonType>
@@ -24831,7 +25050,7 @@ class json_sax_error_forwarder : public json_sax_acceptor<BasicJsonType>
return user->parse_error(position, last_token, ex);
}
/// whether the library parser reported an error
/// whether the default parser reported an error
bool reported() const noexcept
{
return forwarded;
@@ -24850,8 +25069,8 @@ struct sax_ignores_number_text<json_sax_error_forwarder<BasicJsonType, SAX>> : s
a user's handler @a sax
contiguous_parser reports to @a sax what it reads, and stops at the token that
the library parser would reject, before reporting it: the events up to an error
are the same. The error itself is then reported by the library parser (see
the default parser would reject, before reporting it: the events up to an error
are the same. The error itself is then reported by the default parser (see
json_sax_error_forwarder).
@return whether @a result is the result of sax_parse(); false if the input is
@@ -24872,14 +25091,14 @@ bool sax_parse_contiguous(InputAdapterType& adapter, SAX* sax, bool& result, std
}
if (p.aborted())
{
// the handler returned false, as with the library parser
// the handler returned false, as with the default parser
result = false;
return true;
}
}
json_sax_error_forwarder<BasicJsonType, SAX> forwarder(sax);
result = parser<BasicJsonType, InputAdapterType>(InputAdapterType(adapter), nullptr, true, false, false).sax_parse(&forwarder, true);
// the library parser must reject the input as well (the events after the
// the default parser must reject the input as well (the events after the
// byte contiguous_parser stopped at cannot be delivered any more)
JSON_ASSERT(forwarder.reported());
return true;
@@ -41980,7 +42199,7 @@ public:
{
basic_json result;
// JSON in one block of memory, with the default options, is read by
// the faster contiguous_parser; on an error, the library parser reads
// the faster contiguous_parser; on an error, the default parser reads
// it again to report it (see contiguous_parser)
using contiguous = std::integral_constant<bool, detail::can_parse_contiguous<basic_json, typename std::decay<InputAdapterType>::type>::value>;
if (cb == nullptr && !ignore_comments && !ignore_trailing_commas
@@ -41998,8 +42217,8 @@ public:
const bool ignore_comments,
const bool ignore_trailing_commas)
{
// JSON in one block of memory is checked by the faster
// contiguous_parser (see parse_impl())
// JSON in one block of memory, with the default options, is checked by
// the faster contiguous_parser (see parse_impl())
using adapter_t = typename std::decay<InputAdapterType>::type;
bool accepted = false;
if (!ignore_comments && !ignore_trailing_commas
@@ -42023,8 +42242,9 @@ public:
{
if (format == input_format_t::json)
{
// JSON in one block of memory is read by the faster
// contiguous_parser, with the default options (see parse_impl())
// JSON in one block of memory, with the default options, is read by
// the faster contiguous_parser; on an error, the default parser
// reads it again to report it (see parse_impl())
bool result = false;
if (strict && !ignore_comments && !ignore_trailing_commas
&& detail::sax_parse_contiguous<basic_json>(ia, sax, result, std::integral_constant<bool, detail::can_parse_contiguous<basic_json, InputAdapterType>::value> {}))
@@ -47446,6 +47666,7 @@ struct formatter<nlohmann::NLOHMANN_BASIC_JSON_TPL, char> // NOLINT(cert-dcl58-c
#undef JSON_DISABLE_ENUM_SERIALIZATION
#undef JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
#undef JSON_UNLOCKED_FILE_IO
#undef JSON_FILE_WINDOW
#undef JSON_DTOA_SSE2
#undef JSON_DTOA_NEON
#undef JSON_LITTLE_ENDIAN_TARGET
tests/src/unit-contiguous_parser.cpp
+2 -2
View File
@@ -201,7 +201,7 @@ void check_same_events(const std::string& text, const std::list<char>& bytes)
CHECK(r1 == r2);
CHECK(contiguous.log() == byte_path.log());
}
// a handler that asks to go on after an error (the library parser then
// a handler that asks to go on after an error (the default parser then
// reports what follows, e.g., the missing end of the input)
event_log contiguous(static_cast<std::size_t>(-1), true);
event_log byte_path(static_cast<std::size_t>(-1), true);
@@ -545,7 +545,7 @@ TEST_CASE("contiguous parser")
CHECK_FALSE(narrow_json::accept("34028236e31"));
}
SECTION("callbacks, comments and trailing commas take the library parser")
SECTION("callbacks, comments and trailing commas take the default parser")
{
// (the results are those of the options; the contiguous parser does not support them)
CHECK(json::parse("[1,]", nullptr, true, false, true) == json({1}));
tests/src/unit-file_input.cpp
+133
View File
@@ -49,6 +49,14 @@ file_ptr open_with(const char* name, const std::string& content)
return {std::fopen(name, "rb"), &std::fclose};
}
// the smallest size setvbuf() accepts for _IOFBF: the Microsoft C runtime
// rejects sizes below 2 as an invalid parameter, which ends the process
#if defined(_WIN32)
constexpr int min_full_buffer = 2;
#else
constexpr int min_full_buffer = 1;
#endif
// The stdio lock is recursive, so whether parsing released it can only be
// seen from another thread: ftrylockfile() fails there while this thread
// holds the lock. ftrylockfile() is POSIX; elsewhere, the check is skipped.
@@ -225,6 +233,131 @@ TEST_CASE("parsing from a FILE*")
check_unlocked(f.get());
}
#if !defined(JSON_NOEXCEPTION)
SECTION("tokens across the edges of the file's buffer")
{
// the adapter reads the buffer of the FILE directly where it can (see
// JSON_FILE_WINDOW): with buffers of 1 to 70 bytes and none, every
// token crosses an edge somewhere; the results, the error messages
// and their positions must be those of the string
const std::vector<std::string> documents =
{
input,
R"({"long": "a string that is longer than the buffer of the file, with \"escapes\" and \u00e4", "n": [123456789012345678901, -0.000123e-45, 1.5E+300, 0, -0]})",
"[\n \"indented\",\n \"caf\xc3\xa9 \xe2\x82\xac \xf0\x9f\x98\x80\",\n {\n \"key\": 1\n }\n]",
R"({"a": [1, 2, 3], "b": "unterminated)",
R"([1, 2, 3, 1e999])",
R"({"a": "invalid escape \x"})",
"[\"invalid UTF-8 \xc3\x28\"]",
"[1, 2, 3] trailing",
R"([truex])",
};
for (const auto& document : documents)
{
std::string expected;
try
{
expected = json::parse(document).dump();
}
catch (const json::exception& e)
{
expected = e.what();
}
const bool expected_accept = json::accept(document);
for (int size = 0; size <= 70; ++size)
{
if (size != 0 && size < min_full_buffer)
{
continue;
}
CAPTURE(document)
CAPTURE(size)
std::vector<char> buffer(static_cast<std::size_t>(size) + 1);
for (int pass = 0; pass < 2; ++pass)
{
const file_ptr f = open_with(name, document);
REQUIRE(f != nullptr);
// size 0: unbuffered
REQUIRE(std::setvbuf(f.get(), size == 0 ? nullptr : buffer.data(), size == 0 ? _IONBF : _IOFBF, static_cast<std::size_t>(size)) == 0);
if (pass == 0)
{
std::string actual;
try
{
actual = json::parse(f.get()).dump();
}
catch (const json::exception& e)
{
actual = e.what();
}
CHECK(actual == expected);
}
else
{
CHECK(json::accept(f.get()) == expected_accept);
}
check_unlocked(f.get());
}
}
}
}
#endif
// the C standard guarantees only one pushed-back character (and the
// Windows C runtime fails further calls to ungetc()), so this is limited
// to the C libraries that keep them in a separate buffer
#if !defined(JSON_NOEXCEPTION) && ((defined(__GLIBC__) && !defined(__UCLIBC__)) || defined(__APPLE__))
SECTION("characters pushed back with ungetc() before parsing")
{
const file_ptr f = open_with(name, "2, 3]");
REQUIRE(f != nullptr);
REQUIRE(std::ungetc(',', f.get()) == ',');
REQUIRE(std::ungetc('1', f.get()) == '1');
REQUIRE(std::ungetc('[', f.get()) == '[');
CHECK(json::parse(f.get()) == json({1, 2, 3}));
}
#endif
SECTION("SAX events across the edges of the file's buffer")
{
const std::string document = R"({"key": "a value that is longer than the buffer", "n": [1, -2.5e3, true, null]})";
std::vector<long> expected;
{
const file_ptr f = open_with(name, document);
REQUIRE(f != nullptr);
position_reading_sax sax(f.get());
CHECK(json::sax_parse(f.get(), &sax));
expected = sax.positions();
}
for (int size = min_full_buffer; size <= 20; ++size)
{
CAPTURE(size)
std::vector<char> buffer(static_cast<std::size_t>(size));
const file_ptr f = open_with(name, document);
REQUIRE(f != nullptr);
REQUIRE(std::setvbuf(f.get(), buffer.data(), _IOFBF, buffer.size()) == 0);
position_reading_sax sax(f.get());
CHECK(json::sax_parse(f.get(), &sax));
// the events happen at the same positions of the file
CHECK(sax.positions() == expected);
}
}
SECTION("binary strings across the edges of the file's buffer")
{
const json value = {{"a string that is longer than the buffer of the file", "and a value that is longer, too"}, {"n", {1, 2}}};
const std::vector<std::uint8_t> cbor = json::to_cbor(value);
for (int size = min_full_buffer; size <= 20; ++size)
{
CAPTURE(size)
std::vector<char> buffer(static_cast<std::size_t>(size));
const file_ptr f = open_with(name, std::string(cbor.begin(), cbor.end()));
REQUIRE(f != nullptr);
REQUIRE(std::setvbuf(f.get(), buffer.data(), _IOFBF, buffer.size()) == 0);
CHECK(json::from_cbor(f.get()) == value);
}
}
SECTION("binary formats read from a FILE*")
{
const json j = {{"string", std::string(300, 'x')}, {"array", {1, 2, 3}}, {"number", 1.5}};