tests/benchmarks/json_view/ holds a comparison with other
libraries, answering the question users ask when they pick one.
It is not built by CMake and not run by CI.
- bench_view.cpp: parse, traverse, select and dump of twitter,
citm_catalog, canada, jeopardy, a tweet and an RPC request,
against json_view, yyjson, simdjson, Boost.JSON and json::parse,
all agreeing and run interleaved.
- bench_corpus.cpp: parse, traverse and dump of any file list.
- bench_edit.cpp: parses, edits through each library's own API,
and serializes; all outputs must describe the same value.
- compare.py: builds both programs with system or pinned,
SHA-256-checked downloads, and writes results with the commit,
CPU, OS, compiler and library versions.
- README.md and a workflow that runs on demand or via a PR label.
Fairness fixes folded in: each engine runs once untimed before
each timed round, so the next one no longer pays for the
previous one's cleanup; dump is also compared with source numbers
against yyjson's raw-number mode; a "simdjson DOM (fresh)" column
and a reused-document column for json_view were added;
compare.py's paths are absolute; downloads use a .part file and a
failed checksum removes the archive.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
- dtoa_impl::powers_of_ten() (10^0 to 10^19, one entry per line)
replaces powers_of_ten_16() and the table of int_pow10()
- put_literal() takes the length of a string literal from its type
- small_stack holds the heap vector by reference
- the growth step of the output buffer is written in hex
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
The dump and comparison tests moved to their own file in the dump pull
request; the tests of the fast dump() join them there.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
The MinGW linker of the Windows clang jobs cannot link object files with more
than 32767 sections ("relocation truncated to fit: IMAGE_REL_AMD64_REL32
against `.rdata'"). unit-json_view_edit.cpp has 35409 sections since the fast
dump instantiates more code for editable documents, so its test cases "views
and values", "deeply nested values", "pointers below a null value", and
"strings of other documents are checked" move into
unit-json_view_edit_values.cpp. The helper exception_of_call() that both
files use moves into json_view_test_helpers.hpp.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
A float node of an image loaded with image_check::bounds can hold a
token whose bytes are not digits, so its value need not have the digit
count recorded in the node. write_double_at() passed that count to
write_short_decimal(), which indexes its table of powers of ten by it:
an assertion failure in debug builds, an out-of-bounds read in release
builds. Use the counted overload only if the value has exactly that many
digits, otherwise count them.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
The default dump() (no indentation, no ensure_ascii) gets its own
writer that makes the same walk and produces the same output:
- the write position stays in a local variable instead of a
member, so the compiler keeps it in a register across stores
through aliasing char pointers;
- strings and number tokens are copied with fixed-size 32-byte
moves wherever enough source bytes remain, instead of one
memcpy call per token;
- the innermost open container lives in local variables; a stack
that starts as a local array of 32 entries holds the rest;
- unedited documents are walked through the node array in order,
and integer tokens are read from the source directly.
On top of that, float tokens of at most 15 significant digits are
written straight from their digits via zmij::to_shortest() and
write_shortest(), without converting to a double and back: such
decimals are farther apart than a double's rounding interval, so
the token's digits are the double's shortest digits. Tokens of
16+ digits, or edited values, still go through decimal_to_float().
The view's own NEON write_decimal() is removed in favor of the
shared writer, and the dump output now grows in 64 KiB steps
instead of being resized to its estimate at once.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Qt defines emit as an empty macro, so a Qt header included before
json_view.hpp broke the lambda's declaration (see #5865). The slots
variables in the image tests are renamed as well.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
load_result() exists only with exceptions; with JSON_NOEXCEPTION the test
loads the image with the check directly (a failed check aborts).
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
bugprone-suspicious-stringview-data-usage flags data() of the source view
under C++17, although the length is passed and checked by the REQUIRE
before it.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
The full check scanned the contents of every string node and every float token over its own range, so many nodes pointing to one large range made load() quadratic. The structural walk now only collects the ranges; after it, each kind is sorted and checked once per distinct range. Ranges of one kind that overlap without being identical are rejected, as save() never writes them (nodes that share a value share the whole range). The cost is linear in the size of the image plus sorting the ranges.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Move the raw string literal out of the CHECK macro (MSVC preprocessor),
cast 64-bit header fields to std::size_t (C4244 on 32-bit), and give the
image_check section in load.md a real anchor for the mkdocs strict build.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
An image is a document stored so that loading it needs no
parsing: save() writes the node index, the text and the decoded
strings; the static load() reads an image written by save().
load() takes a pointer and size, a borrowed vector, or an owned
rvalue vector; the nodes are copied so they are aligned and can
be edited, while the text and decoded strings stay in the image.
image_check controls how much load() trusts the input: full
checks structure, bounds, strings and numbers, the parser's own
guarantees; bounds checks structure and bounds only; none skips
all checks, for images from a trusted source.
Layout is little-endian only ("NJVI" header, nodes, text, decoded
strings), following the idea of zero-copy formats such as
FlatBuffers and YaFF; the check follows FlatBuffers' Verifier.
New errors: parse_error.116 for a malformed image or a failed
check, type_error.320 for a discarded document or a big-endian
target.
A dedicated fuzzer and 6,000 seeded corruptions, checked under
ASan/UBSan, found and fixed two gaps: unchecked reserved header
fields, and unbounded null/boolean offsets that could make
dump() throw std::length_error.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
The operands of == are unsequenced, and MSVC evaluated
d->edits->chunks.back() before alloc_nodes() added the new chunk, so the
check compared the result with the previous chunk and failed on
msvc-arm64 (Debug and Release).
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
From gregmarr's review of #5630:
- alloc_nodes() gives a request of half of the next chunk or more a chunk
of its own, so that the rest of the current chunk stays available for
smaller requests instead of being abandoned.
- The comments on edit_state, append_text(), and reserve_moved() say that
views stay valid across every edit (not just the first), that n is 0 for
empty strings, and why both capacities are checked.
- The architecture page names flag bits 3, 4, and 5 (linked) separately
and says that a discarded view has no node; erase.md rewords overload 3
and says why it never throws invalid_iterator.202.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Like in the access test, adding the int result of the conditional to a
std::size_t fails -Werror=sign-conversion with GCC.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Since #5622, count() counts every member with the key, so documents
with duplicate keys no longer give 1.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
The review of #5620 renamed document_data's tape/tape_size/tape_cap to
nodes/node_count/node_capacity and made the decode arena a
std::vector<char>; adapt the code of this change to it.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Lookups find the first member of a repeated key again, so set(object, key,
value) assigns that member (keeping the key where it is) and drops the
others, as documented before, and a view taken from object[key] shows the
new value. This undoes the code and documentation changes of 5cbb8e6d6.
Lookups in edited objects (navigation of editable documents) stop at the
first match, like those of parsed objects.
The tests that commit added expect the first member from lookups now. In the
seeded differential test, the documents with repeated keys repeat them after
the real members; the reference holds the first members, which the edits
address and the lookups are compared with, while materialize() is compared
with what parse() makes of the document's dump.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
An editable document reads the last member of a repeated key (as the
read-only document does), but set(object, key, value) assigned the first
one: a view taken from object[key] before the call did not show the new
value. It now assigns the last member's value, keeps the key at the
position of its first occurrence (where materialize() puts it), and drops
the other members.
The seeded differential test now also edits documents whose objects
repeat keys and compares every lookup (operator[], at, find, value,
contains, count, and JSON pointers) with the parsed basic_json value.
A targeted test covers duplicates before and after edits that move the
object, in large objects with an index, in moved arrays, and in values
copied from other documents.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Replacing an array or object that spans several nodes by a scalar looks
up its parent from the root (find_parent), which is linear in the size
of the document: setting every element of a 20,000 element array took
more than half a second. The parent only has to switch to links once;
afterward the extent of the replaced value no longer matters. Nodes that
an entry of a moved sequence links to are now marked (node_flags::linked),
and assign() skips the lookup for them.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
set(json_pointer, value) turned a null parent into an object for every
last reference token, so "/a/0" and "/a/-" below {"a":null} made
{"a":{"0":1}}, where basic_json's operator[](json_pointer) makes an
array. A null parent now becomes an array for "-" and for digit tokens
(filled with nulls up to the index) and an object otherwise. An invalid
index is reported before the parent changes.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
append_text() doubled the capacity of the arena and rejected the result
if it exceeded 4 GiB, so that an arena of more than 2 GiB could not grow
even though the 32-bit offsets of nodes address 4 GiB - 1 bytes. The
capacity is now clamped to that limit (text_capacity()), and an append
is rejected only if the bytes themselves do not fit.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
An editable document only holds valid UTF-8, but copy_scalar() copied the
strings and keys of a view of another document unchecked. A document of
a weaker check (or a borrowed text that changed after parsing) could
therefore bring ill-formed UTF-8 into it. The copy is checked now, with
the error that dump() reports for the string; copies within the same
document stay unchecked.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Counting and copying the nodes of a view or a basic_json value into an
editable document recursed once per nesting level, so that a deeply
nested value overflowed the stack. The four functions now walk the value
with an explicit stack, as materialize() does.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
basic_json_document gets a second template parameter, Editable
(false by default), plus the aliases json_editable_document,
json_editable_view, ordered_json_editable_document and
ordered_json_editable_view.
Editable documents can change values and structure without
rewriting the source text: set()/push_back() on values, keys,
array indices and JSON pointers; insert() before an array
element; erase() of an object key, array index or JSON pointer.
New values and element sequences go into edit storage that the
document owns and never moves, so views keep referring to their
value across edits and a parsed node never moves. Read-only
documents walk the plain node array and are unaffected.
Strings are checked for UTF-8 on entry, so dump() of an editable
document never throws type_error.316. Binary values cannot be
stored (type_error.319).
A seeded differential test applies random edits to an editable
document and to the equivalent ordered_json and compares both
after every step.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Both macros select between definitions of the same inline functions, so
translation units that disagree on them violated the ODR. Like the other
ABI-affecting macros, they now add a tag to the inline namespace (_vns and
_vssse3), and the docs replace the "Define consistently" warning with the
usual ABI compatibility note. From gregmarr's review of #5628.
nlohmann_json.natvis covers twice as many tags now, so it lists four times
as many namespaces (14.7 MB instead of 3.4 MB).
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
From gregmarr's review of #5628:
- Docs and comments say that the hash index is one of the object's keys.
- object_index.hpp: conditional_static_cast for the hash, "slot" for the
table position, no flag for a degenerate table, and a static_assert
that the smallest indexed object is larger than the probe window.
- scan.hpp unrolls with NLOHMANN_VIEW_REPEAT_FIRST_8/SECOND_8.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Qt defines slots as a macro, so a Qt header included before
json_view.hpp broke the declarations of the local variable (see #5865).
The test variable is renamed as well.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
The dump and comparison tests moved to their own file in the dump pull
request; the hash index tests of this branch join them there.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Lookups in objects with 128 members or more return the first member of a
repeated key again, like the linear search of smaller objects. This undoes
the code change of a69542046; its test now expects the first member from
lookups (with and without a table) and the last value from materialize()
and basic_json::parse().
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Lookups in objects with 128 members or more now return the last member of
a repeated key, like the linear search of smaller objects and like
materialize() and basic_json::parse(). build_object_index let the first
occurrence win, so the same text gave different results depending on the
size of the object.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
shrink_to_fit() now trims the tables of large objects like the node array and the decoded strings, and the list of large objects is released as soon as the tables are built.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Niels Lohmann