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Author SHA1 Message Date
Niels Lohmann b2c20c01b1 Rename the reader parameter to avoid a flawfinder false positive
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-14 17:37:46 +02:00
Niels Lohmann 9cbdcb5ed3 Fuzz the streaming input adapters against the contiguous one
The fast paths for contiguous input (bulk string scanning, multi-byte
loads, lazy position tracking) are taken only when parsing from a
pointer range; streams and non-contiguous iterators still read byte by
byte. The fuzzer drivers parsed only contiguous input, so a difference
between the two would ship unnoticed.

check_input_adapters() in fuzzer_common.hpp reads the input through a
std::istringstream, a std::list iterator range, and (on POSIX) a FILE*
from fmemopen, and asserts the same value, or the same exception id,
message and byte position, as for the pointer range. All seven drivers
call it; the JSON driver checks parse and accept, each with and without
ignore_comments. It replaces the stream check of the BON8 driver.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-14 16:33:08 +02:00
12 changed files with 446 additions and 908 deletions

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+78 -167
View File
@@ -772,33 +772,6 @@ class serializer
break;
}
}
// A byte below 0x60 is a complete code point and needs no
// UTF-8 decoding. The scanner stops only at a control
// character, a quote, or a backslash in that range, so look up
// its escape sequence and write all 8 bytes of the table entry
// straight into the write buffer; only the length stored in the
// last byte of the entry is kept.
if (data[i] < 0x60)
{
// emit any bytes still pending in string_buffer first to
// preserve output order
if (bytes != 0)
{
put_buffer(string_buffer, bytes);
bytes = 0;
}
const auto& escape = ascii_escapes()[data[i]];
if (JSON_HEDLEY_UNLIKELY(write_buffer.size() - write_buffer_pos < escape.size()))
{
flush();
}
std::memcpy(write_buffer.data() + write_buffer_pos, escape.data(), escape.size());
write_buffer_pos += static_cast<std::size_t>(escape[7]);
bytes_after_last_accept = 0;
undumped_chars = 0;
continue;
}
}
const auto byte = static_cast<std::uint8_t>(s[i]);
@@ -807,38 +780,91 @@ class serializer
{
case UTF8_ACCEPT: // decode found a new code point
{
// the code point is at least 0x60 (smaller ones are handled
// above) and is not printable ASCII (which the scanner
// copies): it is DEL (0x7F) under EnsureAscii or a non-ASCII
// character
if (EnsureAscii)
switch (codepoint)
{
JSON_ASSERT(codepoint >= 0x7F);
if (error_handler == error_handler_t::keep)
case 0x08: // backspace
{
// this character was buffered as raw bytes below
// in case it turned out to be part of an
// ill-formed sequence (which is kept as is); now
// that it decoded to a well-formed code point,
// undo that and \u-escape it like any other
// character instead
bytes = bytes_after_last_accept;
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = 'b';
break;
}
if (codepoint <= 0xFFFF)
case 0x09: // horizontal tab
{
write_u_escape(bytes, static_cast<std::uint16_t>(codepoint));
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = 't';
break;
}
else
case 0x0A: // newline
{
write_u_escape(bytes, static_cast<std::uint16_t>(0xD7C0u + (codepoint >> 10u)));
write_u_escape(bytes, static_cast<std::uint16_t>(0xDC00u + (codepoint & 0x3FFu)));
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = 'n';
break;
}
case 0x0C: // formfeed
{
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = 'f';
break;
}
case 0x0D: // carriage return
{
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = 'r';
break;
}
case 0x22: // quotation mark
{
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = '"';
break;
}
case 0x5C: // reverse solidus
{
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = '\\';
break;
}
default:
{
// escape control characters (0x00..0x1F) or, if
// EnsureAscii parameter is used, non-ASCII characters
if ((codepoint <= 0x1F) || (EnsureAscii && (codepoint >= 0x7F)))
{
if (EnsureAscii && error_handler == error_handler_t::keep)
{
// this character was buffered as raw bytes
// below in case it turned out to be part of
// an ill-formed sequence (which is kept as
// is); now that it decoded to a well-formed
// code point, undo that and \u-escape it
// like any other character instead
bytes = bytes_after_last_accept;
}
if (codepoint <= 0xFFFF)
{
write_u_escape(bytes, static_cast<std::uint16_t>(codepoint));
}
else
{
write_u_escape(bytes, static_cast<std::uint16_t>(0xD7C0u + (codepoint >> 10u)));
write_u_escape(bytes, static_cast<std::uint16_t>(0xDC00u + (codepoint & 0x3FFu)));
}
}
else
{
// copy byte to buffer (all previous bytes
// been copied have in default case above)
string_buffer[bytes++] = s[i];
}
break;
}
}
else
{
// copy byte to buffer (all previous bytes of the
// sequence have been copied in the default case below)
string_buffer[bytes++] = s[i];
}
// write buffer and reset index; there must be 13 bytes
@@ -1227,121 +1253,6 @@ class serializer
}
}
/*!
@brief the JSON form of each character below 0x60
Entry c holds the escape sequence of character c - the short form for
\\b, \\t, \\n, \\f, \\r, \\" and \\\\, \\u00xx for the other control characters -
or c itself if it needs no escaping, padded with zeros to 7 bytes. The last
byte is the length of the sequence. The 8 bytes of an entry are copied at
once, so writing an escape needs neither a branch nor a byte-wise loop.
*/
static const std::array<std::array<char, 8>, 0x60>& ascii_escapes() noexcept
{
static const std::array<std::array<char, 8>, 0x60> escapes =
{
{
{{'\\', 'u', '0', '0', '0', '0', 0, 6}}, // 0x00
{{'\\', 'u', '0', '0', '0', '1', 0, 6}}, // 0x01
{{'\\', 'u', '0', '0', '0', '2', 0, 6}}, // 0x02
{{'\\', 'u', '0', '0', '0', '3', 0, 6}}, // 0x03
{{'\\', 'u', '0', '0', '0', '4', 0, 6}}, // 0x04
{{'\\', 'u', '0', '0', '0', '5', 0, 6}}, // 0x05
{{'\\', 'u', '0', '0', '0', '6', 0, 6}}, // 0x06
{{'\\', 'u', '0', '0', '0', '7', 0, 6}}, // 0x07
{{'\\', 'b', 0, 0, 0, 0, 0, 2}}, // 0x08
{{'\\', 't', 0, 0, 0, 0, 0, 2}}, // 0x09
{{'\\', 'n', 0, 0, 0, 0, 0, 2}}, // 0x0A
{{'\\', 'u', '0', '0', '0', 'b', 0, 6}}, // 0x0B
{{'\\', 'f', 0, 0, 0, 0, 0, 2}}, // 0x0C
{{'\\', 'r', 0, 0, 0, 0, 0, 2}}, // 0x0D
{{'\\', 'u', '0', '0', '0', 'e', 0, 6}}, // 0x0E
{{'\\', 'u', '0', '0', '0', 'f', 0, 6}}, // 0x0F
{{'\\', 'u', '0', '0', '1', '0', 0, 6}}, // 0x10
{{'\\', 'u', '0', '0', '1', '1', 0, 6}}, // 0x11
{{'\\', 'u', '0', '0', '1', '2', 0, 6}}, // 0x12
{{'\\', 'u', '0', '0', '1', '3', 0, 6}}, // 0x13
{{'\\', 'u', '0', '0', '1', '4', 0, 6}}, // 0x14
{{'\\', 'u', '0', '0', '1', '5', 0, 6}}, // 0x15
{{'\\', 'u', '0', '0', '1', '6', 0, 6}}, // 0x16
{{'\\', 'u', '0', '0', '1', '7', 0, 6}}, // 0x17
{{'\\', 'u', '0', '0', '1', '8', 0, 6}}, // 0x18
{{'\\', 'u', '0', '0', '1', '9', 0, 6}}, // 0x19
{{'\\', 'u', '0', '0', '1', 'a', 0, 6}}, // 0x1A
{{'\\', 'u', '0', '0', '1', 'b', 0, 6}}, // 0x1B
{{'\\', 'u', '0', '0', '1', 'c', 0, 6}}, // 0x1C
{{'\\', 'u', '0', '0', '1', 'd', 0, 6}}, // 0x1D
{{'\\', 'u', '0', '0', '1', 'e', 0, 6}}, // 0x1E
{{'\\', 'u', '0', '0', '1', 'f', 0, 6}}, // 0x1F
{{' ', 0, 0, 0, 0, 0, 0, 1}}, // 0x20
{{'!', 0, 0, 0, 0, 0, 0, 1}}, // 0x21
{{'\\', '"', 0, 0, 0, 0, 0, 2}}, // 0x22
{{'#', 0, 0, 0, 0, 0, 0, 1}}, // 0x23
{{'$', 0, 0, 0, 0, 0, 0, 1}}, // 0x24
{{'%', 0, 0, 0, 0, 0, 0, 1}}, // 0x25
{{'&', 0, 0, 0, 0, 0, 0, 1}}, // 0x26
{{'\'', 0, 0, 0, 0, 0, 0, 1}}, // 0x27
{{'(', 0, 0, 0, 0, 0, 0, 1}}, // 0x28
{{')', 0, 0, 0, 0, 0, 0, 1}}, // 0x29
{{'*', 0, 0, 0, 0, 0, 0, 1}}, // 0x2A
{{'+', 0, 0, 0, 0, 0, 0, 1}}, // 0x2B
{{',', 0, 0, 0, 0, 0, 0, 1}}, // 0x2C
{{'-', 0, 0, 0, 0, 0, 0, 1}}, // 0x2D
{{'.', 0, 0, 0, 0, 0, 0, 1}}, // 0x2E
{{'/', 0, 0, 0, 0, 0, 0, 1}}, // 0x2F
{{'0', 0, 0, 0, 0, 0, 0, 1}}, // 0x30
{{'1', 0, 0, 0, 0, 0, 0, 1}}, // 0x31
{{'2', 0, 0, 0, 0, 0, 0, 1}}, // 0x32
{{'3', 0, 0, 0, 0, 0, 0, 1}}, // 0x33
{{'4', 0, 0, 0, 0, 0, 0, 1}}, // 0x34
{{'5', 0, 0, 0, 0, 0, 0, 1}}, // 0x35
{{'6', 0, 0, 0, 0, 0, 0, 1}}, // 0x36
{{'7', 0, 0, 0, 0, 0, 0, 1}}, // 0x37
{{'8', 0, 0, 0, 0, 0, 0, 1}}, // 0x38
{{'9', 0, 0, 0, 0, 0, 0, 1}}, // 0x39
{{':', 0, 0, 0, 0, 0, 0, 1}}, // 0x3A
{{';', 0, 0, 0, 0, 0, 0, 1}}, // 0x3B
{{'<', 0, 0, 0, 0, 0, 0, 1}}, // 0x3C
{{'=', 0, 0, 0, 0, 0, 0, 1}}, // 0x3D
{{'>', 0, 0, 0, 0, 0, 0, 1}}, // 0x3E
{{'?', 0, 0, 0, 0, 0, 0, 1}}, // 0x3F
{{'@', 0, 0, 0, 0, 0, 0, 1}}, // 0x40
{{'A', 0, 0, 0, 0, 0, 0, 1}}, // 0x41
{{'B', 0, 0, 0, 0, 0, 0, 1}}, // 0x42
{{'C', 0, 0, 0, 0, 0, 0, 1}}, // 0x43
{{'D', 0, 0, 0, 0, 0, 0, 1}}, // 0x44
{{'E', 0, 0, 0, 0, 0, 0, 1}}, // 0x45
{{'F', 0, 0, 0, 0, 0, 0, 1}}, // 0x46
{{'G', 0, 0, 0, 0, 0, 0, 1}}, // 0x47
{{'H', 0, 0, 0, 0, 0, 0, 1}}, // 0x48
{{'I', 0, 0, 0, 0, 0, 0, 1}}, // 0x49
{{'J', 0, 0, 0, 0, 0, 0, 1}}, // 0x4A
{{'K', 0, 0, 0, 0, 0, 0, 1}}, // 0x4B
{{'L', 0, 0, 0, 0, 0, 0, 1}}, // 0x4C
{{'M', 0, 0, 0, 0, 0, 0, 1}}, // 0x4D
{{'N', 0, 0, 0, 0, 0, 0, 1}}, // 0x4E
{{'O', 0, 0, 0, 0, 0, 0, 1}}, // 0x4F
{{'P', 0, 0, 0, 0, 0, 0, 1}}, // 0x50
{{'Q', 0, 0, 0, 0, 0, 0, 1}}, // 0x51
{{'R', 0, 0, 0, 0, 0, 0, 1}}, // 0x52
{{'S', 0, 0, 0, 0, 0, 0, 1}}, // 0x53
{{'T', 0, 0, 0, 0, 0, 0, 1}}, // 0x54
{{'U', 0, 0, 0, 0, 0, 0, 1}}, // 0x55
{{'V', 0, 0, 0, 0, 0, 0, 1}}, // 0x56
{{'W', 0, 0, 0, 0, 0, 0, 1}}, // 0x57
{{'X', 0, 0, 0, 0, 0, 0, 1}}, // 0x58
{{'Y', 0, 0, 0, 0, 0, 0, 1}}, // 0x59
{{'Z', 0, 0, 0, 0, 0, 0, 1}}, // 0x5A
{{'[', 0, 0, 0, 0, 0, 0, 1}}, // 0x5B
{{'\\', '\\', 0, 0, 0, 0, 0, 2}}, // 0x5C
{{']', 0, 0, 0, 0, 0, 0, 1}}, // 0x5D
{{'^', 0, 0, 0, 0, 0, 0, 1}}, // 0x5E
{{'_', 0, 0, 0, 0, 0, 0, 1}}, // 0x5F
}
};
return escapes;
}
/*!
* @brief write a lowercase "\\uXXXX" escape sequence into @a string_buffer
*
+78 -167
View File
@@ -27087,33 +27087,6 @@ class serializer
break;
}
}
// A byte below 0x60 is a complete code point and needs no
// UTF-8 decoding. The scanner stops only at a control
// character, a quote, or a backslash in that range, so look up
// its escape sequence and write all 8 bytes of the table entry
// straight into the write buffer; only the length stored in the
// last byte of the entry is kept.
if (data[i] < 0x60)
{
// emit any bytes still pending in string_buffer first to
// preserve output order
if (bytes != 0)
{
put_buffer(string_buffer, bytes);
bytes = 0;
}
const auto& escape = ascii_escapes()[data[i]];
if (JSON_HEDLEY_UNLIKELY(write_buffer.size() - write_buffer_pos < escape.size()))
{
flush();
}
std::memcpy(write_buffer.data() + write_buffer_pos, escape.data(), escape.size());
write_buffer_pos += static_cast<std::size_t>(escape[7]);
bytes_after_last_accept = 0;
undumped_chars = 0;
continue;
}
}
const auto byte = static_cast<std::uint8_t>(s[i]);
@@ -27122,38 +27095,91 @@ class serializer
{
case UTF8_ACCEPT: // decode found a new code point
{
// the code point is at least 0x60 (smaller ones are handled
// above) and is not printable ASCII (which the scanner
// copies): it is DEL (0x7F) under EnsureAscii or a non-ASCII
// character
if (EnsureAscii)
switch (codepoint)
{
JSON_ASSERT(codepoint >= 0x7F);
if (error_handler == error_handler_t::keep)
case 0x08: // backspace
{
// this character was buffered as raw bytes below
// in case it turned out to be part of an
// ill-formed sequence (which is kept as is); now
// that it decoded to a well-formed code point,
// undo that and \u-escape it like any other
// character instead
bytes = bytes_after_last_accept;
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = 'b';
break;
}
if (codepoint <= 0xFFFF)
case 0x09: // horizontal tab
{
write_u_escape(bytes, static_cast<std::uint16_t>(codepoint));
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = 't';
break;
}
else
case 0x0A: // newline
{
write_u_escape(bytes, static_cast<std::uint16_t>(0xD7C0u + (codepoint >> 10u)));
write_u_escape(bytes, static_cast<std::uint16_t>(0xDC00u + (codepoint & 0x3FFu)));
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = 'n';
break;
}
case 0x0C: // formfeed
{
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = 'f';
break;
}
case 0x0D: // carriage return
{
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = 'r';
break;
}
case 0x22: // quotation mark
{
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = '"';
break;
}
case 0x5C: // reverse solidus
{
string_buffer[bytes++] = '\\';
string_buffer[bytes++] = '\\';
break;
}
default:
{
// escape control characters (0x00..0x1F) or, if
// EnsureAscii parameter is used, non-ASCII characters
if ((codepoint <= 0x1F) || (EnsureAscii && (codepoint >= 0x7F)))
{
if (EnsureAscii && error_handler == error_handler_t::keep)
{
// this character was buffered as raw bytes
// below in case it turned out to be part of
// an ill-formed sequence (which is kept as
// is); now that it decoded to a well-formed
// code point, undo that and \u-escape it
// like any other character instead
bytes = bytes_after_last_accept;
}
if (codepoint <= 0xFFFF)
{
write_u_escape(bytes, static_cast<std::uint16_t>(codepoint));
}
else
{
write_u_escape(bytes, static_cast<std::uint16_t>(0xD7C0u + (codepoint >> 10u)));
write_u_escape(bytes, static_cast<std::uint16_t>(0xDC00u + (codepoint & 0x3FFu)));
}
}
else
{
// copy byte to buffer (all previous bytes
// been copied have in default case above)
string_buffer[bytes++] = s[i];
}
break;
}
}
else
{
// copy byte to buffer (all previous bytes of the
// sequence have been copied in the default case below)
string_buffer[bytes++] = s[i];
}
// write buffer and reset index; there must be 13 bytes
@@ -27542,121 +27568,6 @@ class serializer
}
}
/*!
@brief the JSON form of each character below 0x60
Entry c holds the escape sequence of character c - the short form for
\\b, \\t, \\n, \\f, \\r, \\" and \\\\, \\u00xx for the other control characters -
or c itself if it needs no escaping, padded with zeros to 7 bytes. The last
byte is the length of the sequence. The 8 bytes of an entry are copied at
once, so writing an escape needs neither a branch nor a byte-wise loop.
*/
static const std::array<std::array<char, 8>, 0x60>& ascii_escapes() noexcept
{
static const std::array<std::array<char, 8>, 0x60> escapes =
{
{
{{'\\', 'u', '0', '0', '0', '0', 0, 6}}, // 0x00
{{'\\', 'u', '0', '0', '0', '1', 0, 6}}, // 0x01
{{'\\', 'u', '0', '0', '0', '2', 0, 6}}, // 0x02
{{'\\', 'u', '0', '0', '0', '3', 0, 6}}, // 0x03
{{'\\', 'u', '0', '0', '0', '4', 0, 6}}, // 0x04
{{'\\', 'u', '0', '0', '0', '5', 0, 6}}, // 0x05
{{'\\', 'u', '0', '0', '0', '6', 0, 6}}, // 0x06
{{'\\', 'u', '0', '0', '0', '7', 0, 6}}, // 0x07
{{'\\', 'b', 0, 0, 0, 0, 0, 2}}, // 0x08
{{'\\', 't', 0, 0, 0, 0, 0, 2}}, // 0x09
{{'\\', 'n', 0, 0, 0, 0, 0, 2}}, // 0x0A
{{'\\', 'u', '0', '0', '0', 'b', 0, 6}}, // 0x0B
{{'\\', 'f', 0, 0, 0, 0, 0, 2}}, // 0x0C
{{'\\', 'r', 0, 0, 0, 0, 0, 2}}, // 0x0D
{{'\\', 'u', '0', '0', '0', 'e', 0, 6}}, // 0x0E
{{'\\', 'u', '0', '0', '0', 'f', 0, 6}}, // 0x0F
{{'\\', 'u', '0', '0', '1', '0', 0, 6}}, // 0x10
{{'\\', 'u', '0', '0', '1', '1', 0, 6}}, // 0x11
{{'\\', 'u', '0', '0', '1', '2', 0, 6}}, // 0x12
{{'\\', 'u', '0', '0', '1', '3', 0, 6}}, // 0x13
{{'\\', 'u', '0', '0', '1', '4', 0, 6}}, // 0x14
{{'\\', 'u', '0', '0', '1', '5', 0, 6}}, // 0x15
{{'\\', 'u', '0', '0', '1', '6', 0, 6}}, // 0x16
{{'\\', 'u', '0', '0', '1', '7', 0, 6}}, // 0x17
{{'\\', 'u', '0', '0', '1', '8', 0, 6}}, // 0x18
{{'\\', 'u', '0', '0', '1', '9', 0, 6}}, // 0x19
{{'\\', 'u', '0', '0', '1', 'a', 0, 6}}, // 0x1A
{{'\\', 'u', '0', '0', '1', 'b', 0, 6}}, // 0x1B
{{'\\', 'u', '0', '0', '1', 'c', 0, 6}}, // 0x1C
{{'\\', 'u', '0', '0', '1', 'd', 0, 6}}, // 0x1D
{{'\\', 'u', '0', '0', '1', 'e', 0, 6}}, // 0x1E
{{'\\', 'u', '0', '0', '1', 'f', 0, 6}}, // 0x1F
{{' ', 0, 0, 0, 0, 0, 0, 1}}, // 0x20
{{'!', 0, 0, 0, 0, 0, 0, 1}}, // 0x21
{{'\\', '"', 0, 0, 0, 0, 0, 2}}, // 0x22
{{'#', 0, 0, 0, 0, 0, 0, 1}}, // 0x23
{{'$', 0, 0, 0, 0, 0, 0, 1}}, // 0x24
{{'%', 0, 0, 0, 0, 0, 0, 1}}, // 0x25
{{'&', 0, 0, 0, 0, 0, 0, 1}}, // 0x26
{{'\'', 0, 0, 0, 0, 0, 0, 1}}, // 0x27
{{'(', 0, 0, 0, 0, 0, 0, 1}}, // 0x28
{{')', 0, 0, 0, 0, 0, 0, 1}}, // 0x29
{{'*', 0, 0, 0, 0, 0, 0, 1}}, // 0x2A
{{'+', 0, 0, 0, 0, 0, 0, 1}}, // 0x2B
{{',', 0, 0, 0, 0, 0, 0, 1}}, // 0x2C
{{'-', 0, 0, 0, 0, 0, 0, 1}}, // 0x2D
{{'.', 0, 0, 0, 0, 0, 0, 1}}, // 0x2E
{{'/', 0, 0, 0, 0, 0, 0, 1}}, // 0x2F
{{'0', 0, 0, 0, 0, 0, 0, 1}}, // 0x30
{{'1', 0, 0, 0, 0, 0, 0, 1}}, // 0x31
{{'2', 0, 0, 0, 0, 0, 0, 1}}, // 0x32
{{'3', 0, 0, 0, 0, 0, 0, 1}}, // 0x33
{{'4', 0, 0, 0, 0, 0, 0, 1}}, // 0x34
{{'5', 0, 0, 0, 0, 0, 0, 1}}, // 0x35
{{'6', 0, 0, 0, 0, 0, 0, 1}}, // 0x36
{{'7', 0, 0, 0, 0, 0, 0, 1}}, // 0x37
{{'8', 0, 0, 0, 0, 0, 0, 1}}, // 0x38
{{'9', 0, 0, 0, 0, 0, 0, 1}}, // 0x39
{{':', 0, 0, 0, 0, 0, 0, 1}}, // 0x3A
{{';', 0, 0, 0, 0, 0, 0, 1}}, // 0x3B
{{'<', 0, 0, 0, 0, 0, 0, 1}}, // 0x3C
{{'=', 0, 0, 0, 0, 0, 0, 1}}, // 0x3D
{{'>', 0, 0, 0, 0, 0, 0, 1}}, // 0x3E
{{'?', 0, 0, 0, 0, 0, 0, 1}}, // 0x3F
{{'@', 0, 0, 0, 0, 0, 0, 1}}, // 0x40
{{'A', 0, 0, 0, 0, 0, 0, 1}}, // 0x41
{{'B', 0, 0, 0, 0, 0, 0, 1}}, // 0x42
{{'C', 0, 0, 0, 0, 0, 0, 1}}, // 0x43
{{'D', 0, 0, 0, 0, 0, 0, 1}}, // 0x44
{{'E', 0, 0, 0, 0, 0, 0, 1}}, // 0x45
{{'F', 0, 0, 0, 0, 0, 0, 1}}, // 0x46
{{'G', 0, 0, 0, 0, 0, 0, 1}}, // 0x47
{{'H', 0, 0, 0, 0, 0, 0, 1}}, // 0x48
{{'I', 0, 0, 0, 0, 0, 0, 1}}, // 0x49
{{'J', 0, 0, 0, 0, 0, 0, 1}}, // 0x4A
{{'K', 0, 0, 0, 0, 0, 0, 1}}, // 0x4B
{{'L', 0, 0, 0, 0, 0, 0, 1}}, // 0x4C
{{'M', 0, 0, 0, 0, 0, 0, 1}}, // 0x4D
{{'N', 0, 0, 0, 0, 0, 0, 1}}, // 0x4E
{{'O', 0, 0, 0, 0, 0, 0, 1}}, // 0x4F
{{'P', 0, 0, 0, 0, 0, 0, 1}}, // 0x50
{{'Q', 0, 0, 0, 0, 0, 0, 1}}, // 0x51
{{'R', 0, 0, 0, 0, 0, 0, 1}}, // 0x52
{{'S', 0, 0, 0, 0, 0, 0, 1}}, // 0x53
{{'T', 0, 0, 0, 0, 0, 0, 1}}, // 0x54
{{'U', 0, 0, 0, 0, 0, 0, 1}}, // 0x55
{{'V', 0, 0, 0, 0, 0, 0, 1}}, // 0x56
{{'W', 0, 0, 0, 0, 0, 0, 1}}, // 0x57
{{'X', 0, 0, 0, 0, 0, 0, 1}}, // 0x58
{{'Y', 0, 0, 0, 0, 0, 0, 1}}, // 0x59
{{'Z', 0, 0, 0, 0, 0, 0, 1}}, // 0x5A
{{'[', 0, 0, 0, 0, 0, 0, 1}}, // 0x5B
{{'\\', '\\', 0, 0, 0, 0, 0, 2}}, // 0x5C
{{']', 0, 0, 0, 0, 0, 0, 1}}, // 0x5D
{{'^', 0, 0, 0, 0, 0, 0, 1}}, // 0x5E
{{'_', 0, 0, 0, 0, 0, 0, 1}}, // 0x5F
}
};
return escapes;
}
/*!
* @brief write a lowercase "\\uXXXX" escape sequence into @a string_buffer
*
+10 -1
View File
@@ -9,7 +9,16 @@ Each fuzzer driver (`tests/src/fuzzer-parse_*.cpp`) parses its input twice: once
once with exceptions. Both calls must agree. Where parsing with exceptions fails, the call without exceptions must
return a discarded value (or throw the same kind of non-parse error), and it must never throw a `parse_error`. Where
parsing succeeds, both calls must return the same value. The drivers then serialize the value, parse the result back,
and check that nothing was lost. The drivers check all of this with `assert`, so they refuse to build with `NDEBUG`.
and check that nothing was lost.
Finally, each driver reads the same input through the other input adapters: a `std::istringstream`, a non-contiguous
iterator range (`std::list<std::uint8_t>`), and, on POSIX systems, a `FILE*` from `fmemopen`. The pointer range takes the
fast paths for contiguous input (bulk string scanning, multi-byte loads, lazy position tracking), while the other
adapters read byte by byte. Every adapter must give the same value, or the same exception with the same id, message,
and byte position. The JSON driver checks this for `parse` and `accept`, each with and without `ignore_comments`. The
shared code is `check_input_adapters()` in `tests/src/fuzzer_common.hpp`.
The drivers check all of this with `assert`, so they refuse to build with `NDEBUG`.
## Corpus creation
+21
View File
@@ -47,12 +47,30 @@ dumps is stable under exactly the same values that break operator==.
The unit tests run the same checks on a fixed corpus (see the "BJData round-trip
invariants" test case), so keep both in sync.
Finally, it reads the data from a stream, a non-contiguous iterator range, and
a FILE*, which read byte by byte, and checks that each gives the same value or
error (id, message, byte position) as the pointer range, which takes the bulk
fast paths (see check_input_adapters()).
The provided function `LLVMFuzzerTestOneInput` can be used in different fuzzer
drivers.
*/
#include "fuzzer_common.hpp"
namespace
{
// json::from_bjdata for check_input_adapters()
struct read_bjdata
{
template<typename... Args>
json operator()(Args&& ... args) const
{
return json::from_bjdata(std::forward<Args>(args)...);
}
};
} // namespace
// value-stable comparison for the round-trip checks below; see the note
// above on why this compares dump()s rather than the json values directly
static bool is_value_stable(const json& lhs, const json& rhs)
@@ -126,6 +144,9 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
assert(parsed || noexcept_threw || j_noexcept.is_discarded());
}
// step 3: the other input adapters must read the data alike
check_input_adapters(data, size, read_bjdata());
// return 0 - non-zero return values are reserved for future use
return 0;
}
+13 -21
View File
@@ -17,44 +17,33 @@ array data, it performs the following steps:
- j2 = from_bon8(vec)
- assert(to_bon8(j2) == vec)
It also checks that reading the data from a stream, which reads strings byte by
byte, gives the same value or error as reading it from contiguous memory, which
copies strings in bulk.
Finally, it reads the data from a stream, a non-contiguous iterator range, and
a FILE*, which read byte by byte, and checks that each gives the same value or
error (id, message, byte position) as the pointer range, which takes the bulk
fast paths (see check_input_adapters()).
The provided function `LLVMFuzzerTestOneInput` can be used in different fuzzer
drivers.
*/
#include <sstream>
#include "fuzzer_common.hpp"
namespace
{
// the serialization of the value read from @a input, or the error message
template<typename InputType>
std::string read_bon8(InputType&& input)
// json::from_bon8 for check_input_adapters()
struct read_bon8
{
try
template<typename... Args>
json operator()(Args&& ... args) const
{
const auto vec = json::to_bon8(json::from_bon8(std::forward<InputType>(input)));
return {vec.begin(), vec.end()};
return json::from_bon8(std::forward<Args>(args)...);
}
catch (const json::exception& e)
{
return e.what();
}
}
};
} // namespace
// see http://llvm.org/docs/LibFuzzer.html
extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
{
// contiguous and stream input must be read alike
{
std::istringstream stream(std::string(reinterpret_cast<const char*>(data), size));
assert(read_bon8(std::vector<uint8_t>(data, data + size)) == read_bon8(stream));
}
std::vector<uint8_t> const vec1(data, data + size);
// step 0: parse input without exceptions
@@ -106,6 +95,9 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
assert(parsed || noexcept_threw || j_noexcept.is_discarded());
}
// step 3: the other input adapters must read the data alike
check_input_adapters(data, size, read_bon8());
// return 0 - non-zero return values are reserved for future use
return 0;
}
+21
View File
@@ -17,12 +17,30 @@ array data, it performs the following steps:
- j2 = from_bson(vec)
- assert(to_bson(j2) == vec)
Finally, it reads the data from a stream, a non-contiguous iterator range, and
a FILE*, which read byte by byte, and checks that each gives the same value or
error (id, message, byte position) as the pointer range, which takes the bulk
fast paths (see check_input_adapters()).
The provided function `LLVMFuzzerTestOneInput` can be used in different fuzzer
drivers.
*/
#include "fuzzer_common.hpp"
namespace
{
// json::from_bson for check_input_adapters()
struct read_bson
{
template<typename... Args>
json operator()(Args&& ... args) const
{
return json::from_bson(std::forward<Args>(args)...);
}
};
} // namespace
// see http://llvm.org/docs/LibFuzzer.html
extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
{
@@ -77,6 +95,9 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
assert(parsed || noexcept_threw || j_noexcept.is_discarded());
}
// step 3: the other input adapters must read the data alike
check_input_adapters(data, size, read_bson());
// return 0 - non-zero return values are reserved for future use
return 0;
}
+21
View File
@@ -17,12 +17,30 @@ array data, it performs the following steps:
- j2 = from_cbor(vec)
- assert(to_cbor(j2) == vec)
Finally, it reads the data from a stream, a non-contiguous iterator range, and
a FILE*, which read byte by byte, and checks that each gives the same value or
error (id, message, byte position) as the pointer range, which takes the bulk
fast paths (see check_input_adapters()).
The provided function `LLVMFuzzerTestOneInput` can be used in different fuzzer
drivers.
*/
#include "fuzzer_common.hpp"
namespace
{
// json::from_cbor for check_input_adapters()
struct read_cbor
{
template<typename... Args>
json operator()(Args&& ... args) const
{
return json::from_cbor(std::forward<Args>(args)...);
}
};
} // namespace
// see http://llvm.org/docs/LibFuzzer.html
extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
{
@@ -77,6 +95,9 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
assert(parsed || noexcept_threw || j_noexcept.is_discarded());
}
// step 3: the other input adapters must read the data alike
check_input_adapters(data, size, read_cbor());
// return 0 - non-zero return values are reserved for future use
return 0;
}
+42
View File
@@ -17,6 +17,12 @@ array data, it performs the following steps:
- j2 = parse(s1)
- s2 = serialize(j2)
- assert(s1 == s2)
- for ignore_comments = false and true: assert(parse(data) and accept(data)
give the same result for a stream, a non-contiguous iterator range, and a
FILE* as for the pointer range)
The pointer range takes the bulk fast paths, the other input adapters read byte
by byte; see check_input_adapters().
The provided function `LLVMFuzzerTestOneInput` can be used in different fuzzer
drivers.
@@ -24,6 +30,32 @@ drivers.
#include "fuzzer_common.hpp"
namespace
{
// json::parse and json::accept for check_input_adapters()
struct parse_json
{
bool ignore_comments;
template<typename... Args>
json operator()(Args&& ... args) const
{
return json::parse(std::forward<Args>(args)..., nullptr, true, ignore_comments);
}
};
struct accept_json
{
bool ignore_comments;
template<typename... Args>
bool operator()(Args&& ... args) const
{
return json::accept(std::forward<Args>(args)..., ignore_comments);
}
};
} // namespace
// see http://llvm.org/docs/LibFuzzer.html
extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
{
@@ -76,6 +108,16 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
assert(parsed || noexcept_threw || j_noexcept.is_discarded());
}
// step 3: the other input adapters must read the data alike
for (const bool ignore_comments :
{
false, true
})
{
check_input_adapters(data, size, parse_json{ignore_comments});
check_input_adapters(data, size, accept_json{ignore_comments});
}
// return 0 - non-zero return values are reserved for future use
return 0;
}
+21
View File
@@ -17,12 +17,30 @@ array data, it performs the following steps:
- j2 = from_msgpack(vec)
- assert(to_msgpack(j2) == vec)
Finally, it reads the data from a stream, a non-contiguous iterator range, and
a FILE*, which read byte by byte, and checks that each gives the same value or
error (id, message, byte position) as the pointer range, which takes the bulk
fast paths (see check_input_adapters()).
The provided function `LLVMFuzzerTestOneInput` can be used in different fuzzer
drivers.
*/
#include "fuzzer_common.hpp"
namespace
{
// json::from_msgpack for check_input_adapters()
struct read_msgpack
{
template<typename... Args>
json operator()(Args&& ... args) const
{
return json::from_msgpack(std::forward<Args>(args)...);
}
};
} // namespace
// see http://llvm.org/docs/LibFuzzer.html
extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
{
@@ -77,6 +95,9 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
assert(parsed || noexcept_threw || j_noexcept.is_discarded());
}
// step 3: the other input adapters must read the data alike
check_input_adapters(data, size, read_msgpack());
// return 0 - non-zero return values are reserved for future use
return 0;
}
+21
View File
@@ -26,12 +26,30 @@ array data, it performs the following steps:
The unit tests run the same checks on a fixed corpus (see the "UBJSON round-trip
invariants" test case), so keep both in sync.
Finally, it reads the data from a stream, a non-contiguous iterator range, and
a FILE*, which read byte by byte, and checks that each gives the same value or
error (id, message, byte position) as the pointer range, which takes the bulk
fast paths (see check_input_adapters()).
The provided function `LLVMFuzzerTestOneInput` can be used in different fuzzer
drivers.
*/
#include "fuzzer_common.hpp"
namespace
{
// json::from_ubjson for check_input_adapters()
struct read_ubjson
{
template<typename... Args>
json operator()(Args&& ... args) const
{
return json::from_ubjson(std::forward<Args>(args)...);
}
};
} // namespace
// see http://llvm.org/docs/LibFuzzer.html
extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
{
@@ -96,6 +114,9 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
assert(parsed || noexcept_threw || j_noexcept.is_discarded());
}
// step 3: the other input adapters must read the data alike
check_input_adapters(data, size, read_ubjson());
// return 0 - non-zero return values are reserved for future use
return 0;
}
+94
View File
@@ -11,6 +11,14 @@
#pragma once
#include <cassert> // assert
#include <cstddef> // size_t
#include <cstdint> // uint8_t
#include <cstdio> // FILE, fmemopen, fclose
#include <list> // list
#include <sstream> // istringstream
#include <string> // string
#include <utility> // forward
#include <vector> // vector
#include <nlohmann/json.hpp>
using nlohmann::json; // NOLINT(google-global-names-in-headers): shared by all fuzzer drivers
@@ -49,3 +57,89 @@ json parse_without_exceptions(Parse parse, bool& threw)
}
return {};
}
// the outcome of reading an input with exceptions: the serialization of the
// value, or the id, message, and (for parse errors) byte of the exception
struct read_outcome
{
std::string value{};
int id = 0;
std::string what{};
std::size_t byte = 0;
bool operator==(const read_outcome& rhs) const
{
return value == rhs.value && id == rhs.id && what == rhs.what && byte == rhs.byte;
}
};
inline std::string outcome_value(const json& j)
{
return j.dump(-1, ' ', false, json::error_handler_t::keep);
}
inline std::string outcome_value(bool b)
{
return b ? "true" : "false";
}
template<typename Read, typename... Args>
read_outcome read_with(const Read& parse, Args&& ... args)
{
read_outcome result;
try
{
result.value = outcome_value(parse(std::forward<Args>(args)...));
}
catch (const json::parse_error& e)
{
result.id = e.id;
result.what = e.what();
result.byte = e.byte;
}
catch (const json::exception& e)
{
result.id = e.id;
result.what = e.what();
}
return result;
}
// The contiguous input (a pointer range) takes the bulk fast paths; the other
// input adapters read byte by byte. Reads @a data through each of them and
// checks that all give the same value, or the same exception with the same
// id, message, and byte position.
//
// @a parse is called with either an iterator range or a single input (stream
// or FILE*) and returns the parsed value (or the result of accept()).
template<typename Read>
void check_input_adapters(const std::uint8_t* data, std::size_t size, const Read& parse)
{
const read_outcome expected = read_with(parse, data, data + size);
// stream adapter
{
std::istringstream stream(std::string(reinterpret_cast<const char*>(data), size));
assert(read_with(parse, stream) == expected);
}
// iterator adapter on a non-contiguous range
{
const std::list<std::uint8_t> list(data, data + size);
assert(read_with(parse, list.begin(), list.end()) == expected);
}
#if defined(__unix__) || defined(__APPLE__)
// FILE* adapter; fmemopen may refuse an empty buffer
{
std::vector<std::uint8_t> buffer(data, data + size);
std::FILE* file = buffer.empty() ? nullptr : fmemopen(buffer.data(), buffer.size(), "rb");
if (file != nullptr)
{
const read_outcome actual = read_with(parse, file);
std::fclose(file);
assert(actual == expected);
}
}
#endif
}
+26 -552
View File
@@ -20,11 +20,8 @@
using nlohmann::json;
#include <array>
#include <cstdint>
#include <sstream>
#include <iomanip>
#include <string>
#include <vector>
#include "test_utils.hpp"
@@ -926,68 +923,66 @@ TEST_CASE("serialization boundary values for the string buffer")
// mid-string once fewer than 13 bytes remain (`string_buffer.size() - bytes
// < 13`), 13 being one more than the most a single code point can ever
// write at once (a surrogate pair: two back-to-back "\uXXXX" escapes, 12
// bytes). Characters below 0x60 (control characters, '"' and '\\') are
// escaped straight into the write buffer and never reach string_buffer, so
// under ensure_ascii it fills in steps of 6 (one "\uXXXX" unit for a
// character below U+10000) or 12 (a surrogate pair). With 2-byte characters
// such as U+00E4, `bytes` takes multiples of 6 at the point the check runs;
// the tightest values reachable are therefore 498 (512 - 498 == 14, after
// 83 characters) and 504 (512 - 504 == 8, after 84 characters, where the
// flush fires immediately and resets bytes to 0).
// bytes). Every write into string_buffer that this check protects happens
// in steps of 2 (a simple "\\x" escape) or 6 (one "\uXXXX" unit), so
// `bytes` only ever takes even values at the point the check runs - the
// tightest values actually reachable are therefore 498 (512 - 498 == 14,
// one simple escape away from the threshold) and 500 (512 - 500 == 12,
// where the flush fires immediately and resets bytes to 0).
SECTION("a run of 6-byte escapes lands bytes on, and one step past, the flush threshold")
SECTION("a run of 2-byte escapes lands bytes on, and one step past, the flush threshold")
{
for (const int count :
{
83, 84, 85
249, 250, 251
})
{
CAPTURE(count)
std::string umlauts;
const json j = std::string(static_cast<std::size_t>(count), '\n');
std::string expected = "\"";
for (int i = 0; i < count; ++i)
{
umlauts += "\xC3\xA4";
expected += "\\u00e4";
expected += "\\n";
}
expected += '"';
CHECK(json(umlauts).dump(-1, ' ', true) == expected);
CHECK(j.dump() == expected);
}
}
SECTION("a prefix leaves the tightest reachable margin before a 12-byte surrogate pair")
SECTION("an ASCII prefix leaves the tightest reachable margin before a 12-byte surrogate pair")
{
// U+1F600 (the "\xF0\x9F\x98\x80" UTF-8 bytes) is dumped under
// ensure_ascii as the 12-byte surrogate pair "\ud83d\ude00"; that
// write happens in a single step with no intermediate flush check, so
// it is the write most exposed by an off-by-one in the "< 13" guard.
// A prefix of 83 U+00E4 characters leaves exactly 14 bytes of headroom
// A prefix of 249 newlines leaves exactly 14 bytes of headroom
// (512 - 498), the smallest margin the guard ever actually allows
// into a new code point; 84 characters instead trigger the guard's own
// into a new code point; 250 newlines instead trigger the guard's own
// flush first, so the emoji starts from a freshly emptied (512-byte)
// buffer, and 85 repeats that with one more escape already past the
// buffer, and 251 repeats that with one more escape already past the
// reset. Together they cover the margin the guard allows landing on,
// one step before, and one step after - all must still produce the
// identical, correct escapes.
for (const int prefix_count :
{
83, 84, 85
249, 250, 251
})
{
CAPTURE(prefix_count)
std::string prefix;
std::string expected_prefix;
for (int i = 0; i < prefix_count; ++i)
{
prefix += "\xC3\xA4";
expected_prefix += "\\u00e4";
}
const std::string prefix(static_cast<std::size_t>(prefix_count), '\n');
const std::string emoji = "\xF0\x9F\x98\x80";
const json j = prefix + emoji;
// without ensure_ascii, the whole string is copied unchanged
std::string expected_prefix;
for (int i = 0; i < prefix_count; ++i)
{
expected_prefix += "\\n";
}
// newline escaping does not depend on ensure_ascii: only the
// emoji differs (raw UTF-8 bytes vs. a \u-escaped surrogate pair)
std::string expected_raw = "\"";
expected_raw += prefix;
expected_raw += expected_prefix;
expected_raw += emoji;
expected_raw += '"';
std::string expected_ascii = "\"";
@@ -1032,524 +1027,3 @@ TEST_CASE("serialization boundary values for the string buffer")
}
}
}
namespace
{
// appends the escaped form of the ASCII character c to out; written
// independently of the table in serializer::ascii_escapes()
void append_escaped_ascii(std::string& out, const char c, const bool ensure_ascii)
{
const auto byte = static_cast<unsigned char>(c);
switch (byte)
{
case '\b':
out += "\\b";
break;
case '\t':
out += "\\t";
break;
case '\n':
out += "\\n";
break;
case '\f':
out += "\\f";
break;
case '\r':
out += "\\r";
break;
case '"':
out += "\\\"";
break;
case '\\':
out += "\\\\";
break;
default:
if (byte < 0x20 || (ensure_ascii && byte == 0x7F))
{
// byte < 0x80, so the first two hex digits are 0
const char* const hex = "0123456789abcdef";
out += "\\u00";
out += hex[byte >> 4U];
out += hex[byte & 0x0FU];
}
else
{
out += c;
}
break;
}
}
// reference escaper for ASCII strings
std::string reference_escape_ascii(const std::string& s, const bool ensure_ascii)
{
std::string result = "\"";
for (const char c : s)
{
append_escaped_ascii(result, c, ensure_ascii);
}
result += '"';
return result;
}
} // namespace
TEST_CASE("characters below 0x60 are escaped from a table straight into the write buffer")
{
SECTION("every ASCII character at every position")
{
// lengths up to 17 cover the 8-byte strides of the bulk scanner on
// both sides of the character, so the scanner stops at it from every
// offset
for (std::size_t length = 1; length <= 17; ++length)
{
for (std::size_t pos = 0; pos < length; ++pos)
{
for (unsigned int c = 0; c < 0x80; ++c)
{
std::string s(length, 'a');
s[pos] = static_cast<char>(c);
CAPTURE(length)
CAPTURE(pos)
CAPTURE(c)
const json j = s;
CHECK(j.dump(-1, ' ', false) == reference_escape_ascii(s, false));
CHECK(j.dump(-1, ' ', true) == reference_escape_ascii(s, true));
}
}
}
}
SECTION("runs of escaped characters")
{
std::string s;
for (unsigned int c = 0; c < 0x20; ++c)
{
s += static_cast<char>(c);
}
s += R"("\"\)";
CHECK(json(s).dump() == reference_escape_ascii(s, false));
CHECK(json(s).dump(-1, ' ', true) == reference_escape_ascii(s, true));
}
SECTION("escapes straddle the end of the write buffer")
{
// the 8-byte store of a table entry needs room for all 8 bytes, even
// when the escape itself is shorter; a prefix of k plain characters
// shifts the 6-byte escapes across every offset of the 1024-byte
// write buffer
for (std::size_t k = 0; k < 8; ++k)
{
CAPTURE(k)
const std::string s = std::string(k, 'a') + std::string(400, '\x01');
CHECK(json(s).dump() == reference_escape_ascii(s, false));
CHECK(json::array({s, s}).dump() == "[" + reference_escape_ascii(s, false) + "," + reference_escape_ascii(s, false) + "]");
}
}
SECTION("pending \\u escapes of non-ASCII characters are written first")
{
// under ensure_ascii, U+00E4 is \u-escaped into the string buffer;
// a following escape from the table must not overtake it
const json j = "\xC3\xA4\n\xC3\xA4\"\xF0\x9F\x98\x80\\";
CHECK(j.dump(-1, ' ', true) == "\"\\u00e4\\n\\u00e4\\\"\\ud83d\\ude00\\\\\"");
CHECK(j.dump(-1, ' ', false) == "\"\xC3\xA4\\n\xC3\xA4\\\"\xF0\x9F\x98\x80\\\\\"");
}
SECTION("escapes after invalid UTF-8 for every error handler")
{
const json j = "a\xFF\n\xC3\"";
CHECK_THROWS_WITH_AS(utils::ignore_return_value(j.dump()), "[json.exception.type_error.316] invalid UTF-8 byte at index 1: 0xFF", json::type_error&);
CHECK(j.dump(-1, ' ', false, json::error_handler_t::ignore) == "\"a\\n\\\"\"");
CHECK(j.dump(-1, ' ', true, json::error_handler_t::ignore) == "\"a\\n\\\"\"");
CHECK(j.dump(-1, ' ', false, json::error_handler_t::replace) == "\"a\xEF\xBF\xBD\\n\xEF\xBF\xBD\\\"\"");
CHECK(j.dump(-1, ' ', true, json::error_handler_t::replace) == "\"a\\ufffd\\n\\ufffd\\\"\"");
CHECK(j.dump(-1, ' ', false, json::error_handler_t::keep) == "\"a\xFF\\n\xC3\\\"\"");
CHECK(j.dump(-1, ' ', true, json::error_handler_t::keep) == "\"a\xFF\\n\xC3\\\"\"");
}
}
namespace
{
// expected result of dumping a string: the output, or (with
// error_handler_t::strict) the message of the type_error.316 exception
struct expected_dump
{
bool throws = false;
std::string text{}; // NOLINT(readability-redundant-member-init)
};
std::string upper_hex_byte(const unsigned char byte)
{
const char* const hex = "0123456789ABCDEF";
return std::string(1, hex[byte >> 4U]) + hex[byte & 0x0FU];
}
void append_u_escape(std::string& out, const std::uint32_t code_unit)
{
const char* const hex = "0123456789abcdef";
out += "\\u";
for (int shift = 12; shift >= 0; shift -= 4)
{
out += hex[(code_unit >> static_cast<unsigned int>(shift)) & 0x0FU];
}
}
void append_replacement_character(std::string& out, const bool ensure_ascii)
{
out += ensure_ascii ? "\\ufffd" : "\xEF\xBF\xBD";
}
// reference serializer for arbitrary byte strings, written from the documented
// behavior of dump() and independently of serializer::dump_escaped(): UTF-8 is
// decoded strictly (well-formed sequences as in Table 3-7 of the Unicode
// Standard), and each ill-formed sequence is handled as the error handler says
expected_dump reference_dump_string(const std::string& s, const bool ensure_ascii, const json::error_handler_t error_handler)
{
expected_dump result;
std::string& out = result.text;
out = "\"";
// handle the ill-formed bytes s[begin, end), of which s[index] is the byte
// that could not be decoded; returns false if an exception is expected
const auto ill_formed = [&](const std::size_t begin, const std::size_t end, const std::size_t index)
{
switch (error_handler)
{
case json::error_handler_t::strict:
result.throws = true;
out = "[json.exception.type_error.316] invalid UTF-8 byte at index " + std::to_string(index) + ": 0x" + upper_hex_byte(static_cast<unsigned char>(s[index]));
return false;
case json::error_handler_t::ignore:
break;
case json::error_handler_t::replace:
append_replacement_character(out, ensure_ascii);
break;
case json::error_handler_t::keep:
default:
// kept as is, even with ensure_ascii
out.append(s, begin, end - begin);
break;
}
return true;
};
std::size_t i = 0;
while (i < s.size())
{
const auto lead = static_cast<unsigned char>(s[i]);
if (lead < 0x80)
{
append_escaped_ascii(out, s[i], ensure_ascii);
++i;
continue;
}
// number of bytes of the sequence and the range of its second byte
std::size_t length = 0;
std::uint32_t code_point = 0;
unsigned char lower = 0x80;
unsigned char upper = 0xBF;
if (lead >= 0xC2 && lead <= 0xDF)
{
length = 2;
code_point = lead & 0x1FU;
}
else if (lead >= 0xE0 && lead <= 0xEF)
{
length = 3;
code_point = lead & 0x0FU;
lower = (lead == 0xE0) ? 0xA0 : 0x80; // no overlong encodings
upper = (lead == 0xED) ? 0x9F : 0xBF; // no surrogates
}
else if (lead >= 0xF0 && lead <= 0xF4)
{
length = 4;
code_point = lead & 0x07U;
lower = (lead == 0xF0) ? 0x90 : 0x80; // no overlong encodings
upper = (lead == 0xF4) ? 0x8F : 0xBF; // nothing above U+10FFFF
}
else
{
// a byte that cannot start a sequence is consumed
if (!ill_formed(i, i + 1, i))
{
return result;
}
++i;
continue;
}
std::size_t j = i + 1;
for (; j < i + length; ++j)
{
if (j == s.size())
{
// the string ends in the middle of the sequence
switch (error_handler)
{
case json::error_handler_t::strict:
result.throws = true;
out = "[json.exception.type_error.316] incomplete UTF-8 string; last byte: 0x" + upper_hex_byte(static_cast<unsigned char>(s.back()));
return result;
case json::error_handler_t::ignore:
break;
case json::error_handler_t::replace:
append_replacement_character(out, ensure_ascii);
break;
case json::error_handler_t::keep:
default:
out.append(s, i, s.size() - i);
break;
}
out += '"';
return result;
}
const auto byte = static_cast<unsigned char>(s[j]);
if (byte < lower || byte > upper)
{
break;
}
code_point = (code_point << 6U) | (byte & 0x3FU);
lower = 0x80;
upper = 0xBF;
}
if (j < i + length)
{
// the sequence was abandoned at s[j]; that byte is read again as
// the start of a new character
if (!ill_formed(i, j, j))
{
return result;
}
i = j;
continue;
}
if (!ensure_ascii)
{
out.append(s, i, length);
}
else if (code_point <= 0xFFFF)
{
append_u_escape(out, code_point);
}
else
{
append_u_escape(out, 0xD800U + ((code_point - 0x10000U) >> 10U));
append_u_escape(out, 0xDC00U + ((code_point - 0x10000U) & 0x3FFU));
}
i = j;
}
out += '"';
return result;
}
std::string hex_dump(const std::string& s)
{
std::string result;
for (const char c : s)
{
result += upper_hex_byte(static_cast<unsigned char>(c));
result += ' ';
}
return result;
}
// compares dump() of s with the reference for every error handler, with
// ensure_ascii on and off; CHECKs only on a mismatch to keep the sweep fast;
// error_handler_t::strict can be skipped where the position of the string
// buffer does not matter, as throwing is slow on some platforms
void check_dump_against_reference(const std::string& s, const bool with_strict = true)
{
const json j = s;
const std::array<json::error_handler_t, 4> error_handlers =
{
{
json::error_handler_t::strict, json::error_handler_t::ignore,
json::error_handler_t::replace, json::error_handler_t::keep
}
};
for (const auto error_handler : error_handlers)
{
if (!with_strict && error_handler == json::error_handler_t::strict)
{
continue;
}
for (const bool ensure_ascii :
{
false, true
})
{
const expected_dump expected = reference_dump_string(s, ensure_ascii, error_handler);
expected_dump actual;
int id = 0;
try
{
actual.text = j.dump(-1, ' ', ensure_ascii, error_handler);
}
catch (const json::exception& e)
{
actual.throws = true;
actual.text = e.what();
id = e.id;
}
if (actual.throws != expected.throws || actual.text != expected.text || (actual.throws && id != 316))
{
const std::string input = hex_dump(s);
CAPTURE(input)
CAPTURE(ensure_ascii)
CAPTURE(static_cast<int>(error_handler))
CHECK(actual.throws == expected.throws);
CHECK(actual.text == expected.text);
CHECK((!actual.throws || id == 316));
}
}
}
}
} // namespace
TEST_CASE("invalid UTF-8 at every position is handled like the reference")
{
// ill-formed byte sequences; those that end in a truncated sequence are
// also cut short by the filler that follows, or by the end of the string
const std::vector<std::string> patterns =
{
// stray continuation bytes
"\x80", "\xBF",
// bytes that cannot start a sequence
"\xC0", "\xC1", "\xF5", "\xF6", "\xF7", "\xF8", "\xF9", "\xFA", "\xFB", "\xFC", "\xFD", "\xFE", "\xFF",
// overlong encodings
"\xC0\xAF", "\xE0\x80\x80", "\xF0\x80\x80\x80",
// UTF-16 surrogates
"\xED\xA0\x80", "\xED\xBF\xBF",
// a code point above U+10FFFF
"\xF4\x90\x80\x80",
// sequences cut short by ASCII, a control character, a quote, a
// backslash, DEL, or the lead byte of a well-formed character
"\xC3" "a", "\xE2\x82" "\n", "\xE2\x82\"", "\xF0\x9F\x98\\", "\xC3\x7F", "\xC3\xC3\xA4", "\xE2\xF0\x9F\x98\x80",
// truncated sequences
"\xC3", "\xE2\x82", "\xF0\x9F\x98"
};
// well-formed characters of 1, 2, 3, and 4 bytes
const std::vector<std::string> fillers = {"a", "\xC3\xA4", "\xE2\x82\xAC", "\xF0\x9F\x98\x80"};
const auto make_string = [](const std::string & filler, const std::size_t before, const std::string & pattern, const std::size_t after)
{
std::string s;
for (std::size_t k = 0; k < before; ++k)
{
s += filler;
}
s += pattern;
for (std::size_t k = 0; k < after; ++k)
{
s += filler;
}
return s;
};
SECTION("the reference")
{
// the reference itself, against hand-written results
const std::string s = "a\xFF\n\xC3\"\xE0\x80\xF0\x9F\x98\x80\xE2\x82";
CHECK(reference_dump_string(s, false, json::error_handler_t::strict).text == "[json.exception.type_error.316] invalid UTF-8 byte at index 1: 0xFF");
CHECK(reference_dump_string(s.substr(2), false, json::error_handler_t::strict).text == "[json.exception.type_error.316] invalid UTF-8 byte at index 2: 0x22");
CHECK(reference_dump_string("\xF0\x9F\x98\x80\xE2\x82", true, json::error_handler_t::strict).text == "[json.exception.type_error.316] incomplete UTF-8 string; last byte: 0x82");
CHECK(reference_dump_string(s, false, json::error_handler_t::ignore).text == "\"a\\n\\\"\xF0\x9F\x98\x80\"");
CHECK(reference_dump_string(s, true, json::error_handler_t::ignore).text == "\"a\\n\\\"\\ud83d\\ude00\"");
CHECK(reference_dump_string(s, false, json::error_handler_t::replace).text == "\"a\xEF\xBF\xBD\\n\xEF\xBF\xBD\\\"\xEF\xBF\xBD\xEF\xBF\xBD\xF0\x9F\x98\x80\xEF\xBF\xBD\"");
CHECK(reference_dump_string(s, true, json::error_handler_t::replace).text == "\"a\\ufffd\\n\\ufffd\\\"\\ufffd\\ufffd\\ud83d\\ude00\\ufffd\"");
CHECK(reference_dump_string(s, false, json::error_handler_t::keep).text == "\"" + std::string("a\xFF\\n\xC3\\\"\xE0\x80\xF0\x9F\x98\x80\xE2\x82") + "\"");
CHECK(reference_dump_string(s, true, json::error_handler_t::keep).text == "\"" + std::string("a\xFF\\n\xC3\\\"\xE0\x80\\ud83d\\ude00\xE2\x82") + "\"");
check_dump_against_reference(s);
}
SECTION("short strings")
{
// strings of up to 17 bytes put the pattern at every offset of an
// 8-byte stride of the bulk scanners, with whole strides on both
// sides; lengths around 24, 32, and 40 bytes cross the 16- and 32-byte
// strides; error_handler_t::strict is checked for up to 17 bytes of
// ASCII and 8 bytes of other characters only, as throwing is slow on
// some platforms
for (const auto& filler : fillers)
{
for (std::size_t length = 0; length * filler.size() <= 40; ++length)
{
const std::size_t bytes = length * filler.size();
if (filler.size() == 1 && bytes > 17 && (bytes + 1) % 8 > 2)
{
continue;
}
for (std::size_t pos = 0; pos <= length; ++pos)
{
for (const auto& pattern : patterns)
{
check_dump_against_reference(make_string(filler, pos, pattern, length - pos), bytes <= (filler.size() == 1 ? 17 : 8));
}
}
}
}
}
SECTION("strings crossing the end of the string buffer")
{
// characters that are not copied in bulk go through a 512-byte string
// buffer that is written out once fewer than 13 bytes are left; with
// ensure_ascii, each 2-byte character takes 6 bytes of it and each
// 4-byte character 12, so the pattern meets the end of the buffer after
// about 84 or 42 characters (3-byte characters behave like 2-byte
// ones); plain ASCII, copied in bulk, is checked around 512 bytes;
// positions further away are sampled; error_handler_t::strict throws
// at the first ill-formed byte, regardless of the string buffer, and is
// covered above
for (const auto& filler : fillers)
{
if (filler.size() == 3)
{
continue;
}
const std::size_t escaped_size = filler.size() == 1 ? 1 : filler.size() * 3;
const std::size_t middle = 506 / escaped_size;
const std::size_t window = filler.size() == 1 ? 8 : 16;
for (std::size_t pos = 0; pos <= middle + window; pos += (pos + window >= middle) ? 1 : 29)
{
for (const std::size_t after :
{
std::size_t{0}, std::size_t{12}
})
{
for (const auto& pattern : patterns)
{
check_dump_against_reference(make_string(filler, pos, pattern, after), false);
}
}
}
}
}
SECTION("repeated invalid sequences at every offset of the string buffer")
{
// ill-formed sequences that are kept or replaced fill the string
// buffer without a bulk copy in between; a prefix of 0 to 12 bytes
// 0xFF (kept as 1 byte, replaced by 3 or 6) shifts them across every
// offset of the end of the buffer
for (const auto& pattern : patterns)
{
for (std::size_t shift = 0; shift <= 12; ++shift)
{
std::string s(shift, '\xFF');
while (s.size() < 600)
{
s += pattern;
}
check_dump_against_reference(s, shift == 0);
check_dump_against_reference(s + "\xF0\x9F\x98\x80", false);
}
}
}
}