Memformat

Memformat is a term used in computer science to describe the conventions and rules for representing in-memory data in a form suitable for persistence, transfer, or inter-process communication. It covers how data structures are laid out in memory, how values are encoded, and how they are converted to byte streams. It is not a single standard but a family of practices, often defined within a project or language runtime.

Purpose and scope: Memformat describes the in-memory layout of objects, including field order, data types, size, alignment, and endianness. It is used for serialization formats, memory-mapped I/O, IPC, and database storage. Some projects use a defined memformat to ensure deterministic cross-platform behavior and to simplify versioning.

Core principles: determinism, explicit endianness, fixed field sizes, padding rules, versioning, and backward compatibility. Documentation typically includes a schema or layout description and may include tools to generate or validate layouts, marshaling code, or adapters.

Typical components: a header with a magic token and version, a sequence of typed fields, optional length prefixes, padding for alignment, and a checksum. In memory, pointers and references may be translated to indices or offsets in the serialized form to avoid pointer invalidation.

Variants and challenges: Different ecosystems implement memformat differently, which can hamper interoperability. Design choices impact performance, portability, and safety. Good memformat practices emphasize clear contracts between producer and consumer and careful handling of endianness and versioning.