BoxDB's SQLite engine

This directory vendors libsqlite3-sys 0.38.2 and SQLite 3.53.2. The upstream amalgamation in sqlite3/sqlite3.c is unchanged. boxdb.rs applies checked source transformations at build time; each anchor must match exactly once. The package is published as boxdb-sqlite-sys, retaining the Rust library name libsqlite3_sys. BoxDB and boxdb-rusqlite depend on it directly; consumers need no Cargo patches. SQLite extensions link to this engine.

native_types.rs is the shared native type registry used by Rust and the build. boxdb_native.inc dispatches casts, operators, comparisons, SQL functions and value views. src/temporal.rs implements calendar arithmetic and exact interval scaling. src/temporal_functions.rs implements extract, make_interval, age and date_trunc. SQLite JSON1/JSONB is omitted at compile time; BoxDB validates opaque JSON in Rust.

Adding a native type

Add a Kind and descriptor to native_types.rs: its SQL name, affinity, wire tag and fixed payload size. The build generates C descriptors, affinity constants and SQLite's declaration/type-check tables from that registry. Affinities occupy 0x47 through 0x4f and 0x60; the 0x6f comparison mask excludes SQLite's JUMPIFNULL and NULLEQ bits. Affinity lookup uses the registry rather than assuming contiguous assignments.

Implement parsing, formatting, casts, operators, comparison keys and hashing in Rust behind native.rs. Comparison and hashing must agree with indexes, grouping and uniqueness. boxdb_native.inc supplies the shared C dispatch at SQLite's value, expression and record boundaries; cross-type comparison domains and special numeric behavior still need explicit rules. DECIMAL has a dedicated variable-length codec and numeric backend.

Expose the type in BoxDB's Rust Type/Value enums, schema translation and client value mappings. Native parameters, results and snapshots use a one-byte BLOB type tag, while the SQLite C API retains its five standard storage classes. Test behavior through Database, including scans versus indexes and both snapshot formats. Public Rust values and serialization form the other integration boundary.

Engine integration

boxdb_decimal.inc integrates decimal affinity, arithmetic, comparison, casts, and value accessors into SQLite. The internal decimal precision checker is a built-in, so saved schemas can be restored directly through this engine. boxdb_aggregate.inc implements exact decimal and interval accumulators. src/decimal.rs provides bounded arbitrary-precision arithmetic using BigDecimal and BigInt. This fork requires Rust's standard library and the bundled build. System SQLite, SQLCipher, Gecko, and loadable-extension builds are rejected instead of silently dropping native decimal support.

The standard SQLite page and record format is preserved. Native values and ordinary BLOBs use single-byte type tags. UINT8/16/32 use INTEGER serial types when a column or index declaration supplies their width; OP_Column restores that width before evaluation. Runtime and untyped values keep their tag, while UINT64 always uses a tagged BLOB. src/unsigned.rs implements checked unsigned arithmetic and logical shifts. The database codec version is stored in __boxdb_codec, and readable headers also record it. Stock SQLite does not have compatible query or index semantics. See the decimal contract.

Normal BLOB bind/result APIs add the BYTEA tag. BoxDB transports already encoded cells through the pointer API with the private type boxdb.wire-blob.v1 and a borrowed C descriptor { const char *data; int length; }. The patched API copies the descriptor's bytes immediately and calls a supplied destructor once. This route is used for typed parameters, native decimal function results, and readable snapshot import. Standard C column and scalar-function value accessors expose logical payloads. sqlite3_boxdb_column_blob and its size accessors expose wire cells; the Rust FFI uses these for column BLOB decoding. Incremental BLOB access skips the BYTEA tag and preserves it on writes.

To upgrade SQLite, update the pinned upstream sources and crate build/bindings, then adapt the checked transformations. Run the complete Rust and TypeScript and Go suites, especially tests/native_decimal.rs and tests/native_types.rs; comparison changes must agree across scans, indexes, materialized records, and temporary-file sorting.

Upstream bindings retain their MIT license. SQLite's amalgamation is in the public domain. BoxDB additions use the repository's MIT license.