libdbm 0.3.0

A tiny and fast (1000s read/write per second) database with a simple API (`Map`) for Dart using disk-based hashing. No dependencies, batteries included.

0.1.0 Initial version

• Initial release.

0.1.1 Change github repo

• Changed github repo

0.1.2 Cleanups

• Added an example.
• Cleaned up the source code to improve static analysis.
• Added a little more documentation to the README.

0.1.3 Bug Fix, PersistentMap

• Fixed a bug in clear() where counts were not updated.
• Added an implementation of Map that is disk-persistent.

0.1.4 Cleanups

• Tweak pubspec, minor cleanup.

0.1.5 Cleanups

• Tweak pubspec, minor cleanup.

0.1.6 Null safety changes

• Changes to make the library null-safe.

0.1.7 Clean ups and bug fixes

• Fixes to the block size calculation.
• Cleanups

0.1.8 Clean ups and bug fixes

• Fixed README to align with null-safe API.
• Fixed pedantic errors.

0.2.1 Robustness, readonly mode, compaction

• Added readonly mode with shared file locking (readonly parameter on HashDBM and PersistentMap factories).
• Added compact() method to truncate trailing free blocks and reclaim disk space.
• Added header CRC validation with seal()/validate() to detect header corruption.
• Added file locking (exclusive for read-write, shared for readonly) with a Finalizer safety net.
• Fixed put() to correctly return the previous value instead of the new value.
• Fixed putIfAbsent() to check for existing keys before inserting and to not call the callback when a value exists.
• Fixed clear() to reset numBytes to zero.
• Fixed align() to return the input unchanged when already aligned.
• Fixed memory pool _write() to overwrite stale pointers with Pointer.NIL.
• Optimised bucket flush with dirty-tracking to avoid rewriting the entire bucket array on every flush.
• Added PointerBlock.writeAt() for single-entry writes.
• Bumped version format to 0x00010009.
• Bumped minimum SDK constraint to >=2.17.0.
• Removed stale Flutter/transitive dependencies from pubspec.lock.
• Test files now use distinct filenames to avoid collisions.
• Added regression test suite.

0.2.0 Clean up

• Added a LICENSE files.
• Fixed some formatting issues.

0.3.0 Versioned database, merge & flatten

• Added VersionedHashDBM — delta-overlay transactions with point-in-time snapshots.
• Added Transaction interface (begin, commit, rollback) for atomic versioned writes.
• Added merge() — compact all (or a range of) deltas into the base table.
• Added flatten() — merge all deltas and convert back to plain HashDBM format.
• Added DeltaBlock and VersionStore for on-disk delta storage.
• New exports: VersionedDBM, VersionedHashDBM, Transaction.
• Fixed: opening a new (empty) file with readonly: true now throws instead of creating a corrupt file.
• Fixed: modified() timestamp now updates on every flush.
• Fixed: PersistentMap [], containsKey, and remove return null/false for wrong key types instead of throwing TypeError.
• Fixed: crash-consistency risk where old version-list blocks could be freed before the new header pointer was durably committed.
• Improved: merge() now suppresses per-operation flushing, eliminating severe write amplification.
• Improved: put() and putIfAbsent() eliminate redundant key lookups.
• Improved: MemoryPool.free() uses binary-search insertion instead of full re-sort.