- get_bytes(): replace `len -= static_cast<NumberType>(wanted)` with an
explicit `len = static_cast<NumberType>(len - ...)`. The compound
assignment promoted the operands to int and narrowed back, which GCC
rejects under -Werror=arith-conversion when NumberType is narrower than
int (e.g. UBJSON's int16 length). This also fixes the CodeQL build.
- get_bytes(): add JSON_ASSERT(read == wanted) documenting that
get_elements() never returns more than requested (per review).
- iterator_input_adapter: de-duplicate the iterator_is_contiguous
definition with the #if inside the initializer (per review).
- Add a comment explaining why the memcpy source is &*current (needed for
non-pointer contiguous iterators), and drop the redundant parentheses.
- Run astyle on the new unit test so the amalgamation/format check passes.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The binary reader read CBOR/MessagePack/BSON/UBJSON strings and byte
arrays one byte at a time via get()/push_back(), and the iterator input
adapter's get_elements() fallback was itself a per-byte loop, so even
contiguous inputs never benefited from a block copy.
Two changes:
1. iterator_input_adapter::get_elements() gains a contiguous fast path
that copies the whole requested range with std::memcpy. Contiguity is
detected via std::is_pointer (all standards) and, in C++20,
std::contiguous_iterator (so std::vector/std::string iterators also
qualify). Non-contiguous iterators keep the element-by-element loop.
2. get_string()/get_binary() now share get_bytes(), which reads into the
result in bounded chunks through get_elements() instead of byte by
byte. Capping the chunk size preserves the deliberate "do not
reserve(len) for an untrusted length" DoS protection while turning the
inner loop into block copies. The min(chunk_size, len) computation is
width-safe so narrow length types (e.g. MessagePack ext-8's uint8_t)
cannot truncate chunk_size to zero.
Microbenchmark (2 MiB string + 2 MiB blob + 2000x1 KiB strings, Apple
clang, -O2):
C++20 from_cbor(vector) 20.1 ms -> 1.0 ms (~20x)
from_cbor(pointer) 18.9 ms -> 1.0 ms (~19x)
C++17 from_cbor(pointer) 18.7 ms -> 1.0 ms (~19x, memcpy)
from_cbor(vector) 18.7 ms -> 4.0 ms (~4.6x, tight loop)
Behavior is unchanged: truncated input still throws parse_error.110 at
the same byte offset, and all binary-format unit tests pass.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* fix(cbor): reject negative ints overflowing int64
CBOR encodes negative integers as "-1 - n" where n is uint64_t. When
n > INT64_MAX, casting to int64_t caused undefined behavior and silent
data corruption. Large negative values were incorrectly parsed as
positive integers (e.g., -9223372036854775809 became 9223372036854775807).
Add bounds check for to reject values that exceed int64_t
representable range, returning parse_error instead of silently
corrupting data.
Added regression test cases to verify.
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
* chore: clarify tests
Add test for "n=0" case (result=-1) to cover the smallest magnitude
boundary. Update comments to explain CBOR 0x3B encoding and why
"result=0" is not possible. Clarify that n is an unsigned integer
in the formula "result = -1 - n" to help understanding the tests.
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
* fix(cbor): extend overflow checks for other types
Extend negative integer overflow detection to all CBOR negative
integer cases (0x38, 0x39, 0x3A) for consistency with the existing
0x3B check.
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
---------
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
* Add implementation to retrieve start and end positions of json during parse
* Add more unit tests and add start/stop parsing for arrays
* Add raw value for all types
* Add more tests and fix compiler warning
* Amalgamate
* Fix CLang GCC warnings
* Fix error in build
* Style using astyle 3.1
* Fix whitespace changes
* revert
* more whitespace reverts
* Address PR comments
* Fix failing issues
* More whitespace reverts
* Address remaining PR comments
* Address comments
* Switch to using custom base class instead of default basic_json
* Adding a basic using for a json using the new base class. Also address PR comments and fix CI failures
* Address decltype comments
* Diagnostic positions macro (#4)
Co-authored-by: Sush Shringarputale <sushring@linux.microsoft.com>
* Fix missed include deletion
* Add docs and address other PR comments (#5)
* Add docs and address other PR comments
---------
Co-authored-by: Sush Shringarputale <sushring@linux.microsoft.com>
* Address new PR comments and fix CI tests for documentation
* Update documentation based on feedback (#6)
---------
Co-authored-by: Sush Shringarputale <sushring@linux.microsoft.com>
* Address std::size_t and other comments
* Fix new CI issues
* Fix lcov
* Improve lcov case with update to handle_diagnostic_positions call for discarded values
* Fix indentation of LCOV_EXCL_STOP comments
* fix amalgamation astyle issue
---------
Co-authored-by: Sush Shringarputale <sushring@linux.microsoft.com>
Niels LohmannandClaude Opus 4.8
Ville Vesilehto
Sushrut ShringarputaleandSush Shringarputale
Florian Albrechtskirchinger