highperfocused/bitcoin
1
0
Fork 0
mirror of https://github.com/bitcoin/bitcoin.git synced 2026-04-09 07:08:25 +02:00
Code Issues Packages Projects Releases Wiki Activity

Merge bitcoin/bitcoin#34436: refactor: add overflow-safe CeilDiv helper and use it in unsigned callsites

Browse Source 
02d047fd5b refactor: add overflow-safe `CeilDiv` helper (Lőrinc)

Pull request description:

  ### Problem
  The codebase has many open-coded ceiling-division expressions (for example `(x+y-1)/y`) scattered across files.
  These are less readable, duplicate logic, and can be overflow-prone in edge cases.

  ### Fix
  Introduce a small overflow-safe integer helper, `CeilDiv()`, and use it in existing **unsigned** callsites where the conversion is straightforward and noise-free.

  ### What this PR does
  * Adds `CeilDiv()` to `src/util/overflow.h` for unsigned integral inputs.
  * Keeps the precondition check `assert(divisor > 0)`.
  * Replaces selected unsigned ceiling-division expressions with `CeilDiv(...)`.
  * Adds focused unit tests in `src/test/util_tests.cpp` for the migrated patterns.

  ---

  This is a pure refactor with no intended behavioral change.
  Signed arithmetic callsites are intentionally left unchanged in this PR.
  This PR changed a few more things originally but based on feedback reverted to the simplest cases only.

ACKs for top commit:
  rustaceanrob:
    ACK 02d047fd5b
  hodlinator:
    ACK 02d047fd5b
  sedited:
    ACK 02d047fd5b

Tree-SHA512: b09336031f487e6ce289822e0ffeb8cfc8cfe8a2f4f3f49470748dfbd0a6cbab97498674cb8686dd2bd4ab6dd0b79cfdf2da00041fee12d109892e1bc5dde0ff
This commit is contained in:
merge-script
2026-03-11 11:30:42 +01:00
parent 7c21413616 02d047fd5b
commit b62abc7eec
15 changed files with 85 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

37
src/test/util_tests.cpp
View File

@@ -1834,4 +1834,41 @@ BOOST_AUTO_TEST_CASE(mib_string_literal_test)
BOOST_CHECK_EXCEPTION(operator""_MiB(static_cast<unsigned long long>(max_mib) + 1), std::overflow_error, HasReason("MiB value too large for size_t byte conversion"));
}
BOOST_AUTO_TEST_CASE(ceil_div_test)
{
// Type combinations used by current CeilDiv callsites.
BOOST_CHECK((std::is_same_v<decltype(CeilDiv(uint32_t{0}, 8u)), uint32_t>));
BOOST_CHECK((std::is_same_v<decltype(CeilDiv(size_t{0}, 8u)), size_t>));
BOOST_CHECK((std::is_same_v<decltype(CeilDiv(unsigned{0}, size_t{1})), size_t>));
// `common/bloom.cpp` and `cuckoocache.h` patterns.
BOOST_CHECK_EQUAL(CeilDiv(uint32_t{3}, 2u), uint32_t{2});
BOOST_CHECK_EQUAL(CeilDiv(uint32_t{65}, 64u), uint32_t{2});
BOOST_CHECK_EQUAL(CeilDiv(uint32_t{9}, 8u), uint32_t{2});
// `key_io.cpp`, `rest.cpp`, `merkleblock.cpp`, `strencodings.cpp` patterns.
BOOST_CHECK_EQUAL(CeilDiv(size_t{9}, 8u), size_t{2});
BOOST_CHECK_EQUAL(CeilDiv(size_t{10}, 3u), size_t{4});
BOOST_CHECK_EQUAL(CeilDiv(size_t{11}, 5u), size_t{3});
BOOST_CHECK_EQUAL(CeilDiv(size_t{41} * 8, 5u), size_t{66});
// `flatfile.cpp` mixed unsigned/size_t pattern.
BOOST_CHECK_EQUAL(CeilDiv(unsigned{10}, size_t{4}), size_t{3});
// `util/feefrac.h` fast-path rounding-up pattern.
constexpr int64_t fee{12345};
constexpr int32_t at_size{67};
constexpr int32_t size{10};
BOOST_CHECK_EQUAL(CeilDiv(uint64_t(fee) * at_size, uint32_t(size)),
(uint64_t(fee) * at_size + uint32_t(size) - 1) / uint32_t(size));
// `bitset.h` template parameter pattern.
constexpr unsigned bits{129};
constexpr size_t digits{std::numeric_limits<size_t>::digits};
BOOST_CHECK_EQUAL(CeilDiv(bits, digits), (bits + digits - 1) / digits);
// `serialize.h` varint scratch-buffer pattern.
BOOST_CHECK_EQUAL(CeilDiv(sizeof(uint64_t) * 8, 7u), (sizeof(uint64_t) * 8 + 6) / 7);
}
BOOST_AUTO_TEST_SUITE_END()