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1e101ecac1
* Add BON8 support Add to_bon8/from_bon8 and input_format_t::bon8 for BON8, a binary format that uses the byte values that cannot begin a UTF-8 character as type markers, so strings need no length prefix. It is the most compact of the supported binary formats on the benchmark files. The reader is non-recursive like the other binary readers. A string ends at the first byte that cannot continue it, so the reader hands the one or two bytes it reads past a string back to the value that follows. The writer produces the canonical representation of the specification, except for NFC normalization; its output is identical to that of the reference implementation (HikoGUI) on all files of the test data. The round-trip tests need the .bon8 files of json_test_data 3.2.0. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Address review comments - Reuse detail::validate_one_utf8 to check strings in to_bon8; the error now names the first byte of the invalid sequence. - Document that to_bon8 leaves bytes in the output adapter on an exception, and that string_open is only an output of write_bon8_marker. - Explain why the pushback buffer of the BON8 reader cannot overflow. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Select the BON8 float prefix by type get_bon8_float_prefix only depends on the type of its argument, so make the type a template parameter instead of passing an unused value. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Rename a test variable that Flawfinder mistakes for read() Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Fix the BON8 CI failures - compare the float in write_bon8_float with number_float_t constants, so GCC does not warn about a float-to-double conversion - mark check_bon8_utf8's context as used when exceptions are disabled - choose the compact float prefix in a helper rather than with nested conditional operators (clang-tidy) - use auto for the cast in the BON8 integer reader (clang-tidy) - write the int32 minimum test values as long long literals (MSVC C4146) Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Amalgamate Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Read BON8 strings in bulk from contiguous input - copy the valid UTF-8 of a string in one step when the input is contiguous (twitter.json is read in 1.68 instead of 2.52 ms, jeopardy.json in 196 instead of 297 ms, close to CBOR and MessagePack) - share the new valid_utf8_prefix() with the writer's UTF-8 check, which now skips ASCII 8 bytes at a time - let the fuzzer check that contiguous and stream input give the same value or error, and test both paths in the unit tests - clarify that a second 0xFF after a string is an empty string Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Link the BON8 functions from the other binary format pages Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Name the bulk scan flag after the input, not BON8 Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Read BSON keys in bulk from contiguous input BSON keys (and array indices) are C-style strings, which were read byte by byte. For contiguous input they are now read up to their \x00-byte in one step, using the same bulk_scan flag as BON8 strings: twitter.json is read in 1.46 instead of 2.01 ms, citm_catalog.json in 2.93 instead of 3.33 ms, jeopardy.json in 182 instead of 207 ms. canada.json, whose keys are almost all one-digit array indices, takes 2 % longer. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Fix the BON8 CI failures of the bulk-read tests - skip the contiguous-versus-stream tests of BON8 strings and BSON keys when exceptions are disabled: they catch the parse errors of invalid input, and without exceptions the library aborts instead - use static_cast for the int64 test value (google-readability-casting) Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Move the explicit basic_json instantiation into its own test file Linking test-regression3_cpp20 with clang and MinGW failed with "relocation truncated to fit: IMAGE_REL_AMD64_REL32 against `.rdata'", as test-regression2 did before #5511. The explicit instantiation of basic_json<> for #4825 compiles every member function, including the BON8 reader and writer, into that object, and it was already close to the limit (2,226,104 bytes on develop, 2,234,960 with BON8; clang -O1, C++20). Give the instantiation a file of its own: unit-regression3 is now 1,594,736 bytes and unit-explicit_instantiation 1,095,064. The new file mentions JSON_HAS_CPP_17 and JSON_HAS_CPP_20 so it keeps being built for the C++17 standard the regression was about. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Convert the bytes of the BON8 test strings explicitly The str() helper constructed a std::string from a byte range, which converts each unsigned char implicitly; -fsanitize=integer reports that for bytes of 0x80 and above (ci_test_clang_sanitizer). Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
104 lines
2.8 KiB
C++
104 lines
2.8 KiB
C++
// __ _____ _____ _____
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// __| | __| | | | JSON for Modern C++ (supporting code)
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// | | |__ | | | | | | version 3.12.0
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// |_____|_____|_____|_|___| https://github.com/nlohmann/json
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//
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// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
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// SPDX-License-Identifier: MIT
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/*
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This file implements a parser test suitable for fuzz testing. Given a byte
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array data, it performs the following steps:
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- j1 = from_bon8(data)
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- vec = to_bon8(j1)
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- j2 = from_bon8(vec)
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- assert(j1 == j2)
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It also checks that reading the data from a stream, which reads strings byte by
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byte, gives the same value or error as reading it from contiguous memory, which
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copies strings in bulk.
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The provided function `LLVMFuzzerTestOneInput` can be used in different fuzzer
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drivers.
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*/
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#include <cassert>
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#include <iostream>
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#include <sstream>
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#include <nlohmann/json.hpp>
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// the round-trip checks below are assertions; NDEBUG would compile them away
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#ifdef NDEBUG
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#error "the fuzzer drivers must be built without NDEBUG"
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#endif
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using json = nlohmann::json;
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namespace
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{
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// the serialization of the value read from @a input, or the error message
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template<typename InputType>
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std::string read_bon8(InputType&& input)
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{
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try
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{
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const auto vec = json::to_bon8(json::from_bon8(std::forward<InputType>(input)));
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return {vec.begin(), vec.end()};
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}
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catch (const json::exception& e)
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{
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return e.what();
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}
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}
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} // namespace
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// see http://llvm.org/docs/LibFuzzer.html
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extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
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{
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// contiguous and stream input must be read alike
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{
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std::istringstream stream(std::string(reinterpret_cast<const char*>(data), size));
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assert(read_bon8(std::vector<uint8_t>(data, data + size)) == read_bon8(stream));
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}
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try
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{
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// step 1: parse input
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std::vector<uint8_t> const vec1(data, data + size);
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json const j1 = json::from_bon8(vec1);
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try
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{
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// step 2: round trip
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std::vector<uint8_t> const vec2 = json::to_bon8(j1);
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// parse serialization
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json const j2 = json::from_bon8(vec2);
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// serializations must match
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assert(json::to_bon8(j2) == vec2);
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}
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catch (const json::parse_error&)
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{
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// parsing a BON8 serialization must not fail
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assert(false);
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}
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}
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catch (const json::parse_error&)
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{
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// parse errors are ok, because input may be random bytes
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}
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catch (const json::type_error&)
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{
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// type errors can occur during parsing, too
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}
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catch (const json::out_of_range&)
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{
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// out of range errors may happen if provided sizes are excessive
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}
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// return 0 - non-zero return values are reserved for future use
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return 0;
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}
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