License
BSD-3-Clause
ddn.columnar.memory
The memory layer of ddn.df: aligned GC-owned buffers, the single trusted sealing step and the safe typed view (D2, D9, D13; ADR-2026-10-18-07).
All chunk storage goes through allocAligned: zeroed (GC.calloc, fact 5 — GC.malloc hands out stale words, which would corrupt bitmap builders), BlkAttr.NO_SCAN for element types without indirections, over-allocated by BUFFER_ALIGNMENT bytes and returned as the 64-byte aligned interior slice (fact 3 — the collector keeps an interior slice alive across collections and GC.addrOf resolves it). Keeping allocation behind one helper is what allows an allocator parameter later.
Copyright
Copyright (c) 2026, DDN (D Developer Network) Members
Functions 5
fn
T[] allocAligned(T)(size_t count) @trusted pure nothrowAllocates a zeroed, `BUFFER_ALIGNMENT`-aligned, GC-owned buffer of `count` elements of `T`.fn
T[] allocAlignedRaw(T)(size_t count) @trusted pure nothrowThe unzeroed counterpart of `allocAligned`, for value buffers the caller fully overwrites before anyone can read them (the value runs of the primitive and string builders): null slots hold arbitrar...fn
immutable(T)[] seal(T)(ref T[] buffer) @trusted pure nothrowSeals a mutable builder buffer into immutable chunk storage (D3).fn
immutable(ubyte)[] sealBytes(T)(ref T[] buffer) @trusted pure nothrowSeals a builder buffer and returns it as raw immutable bytes, the form `ArrayData` stores. Always seal through this helper instead of writing `cast(immutable(ubyte)[]) seal(buf)`: GDC 16.2 miscompi...fn
immutable(T)[] typedView(T)(immutable(ubyte)[] raw) @safe pure nothrowReinterprets a sealed byte buffer as typed values (D2). A plain cast of `immutable(ubyte)[]` to `immutable(T)[]` is accepted in `@safe` code under dip1000 on all four compilers, and the runtime ins...Variables 1
enumvar
BUFFER_ALIGNMENT = 64Every chunk buffer is aligned to this many bytes, so a later zero-copy Arrow C Data Interface or Parquet bridge (the ddn-data-parquet repository) needs no re-layout (D1).