cstruct

Quick start ​

Everything public lives on the c namespace: decorators, field helpers, and struct I/O.

ts
import { c } from "@craftycodie/cstruct";

@c.struct()
class Example {
  @c.field("u32")
  value!: number;
}

const bytes = c.write(Example, { value: 42 } as Example, "big");
const instance = c.read(Example, bytes, "big");

console.log(instance.value); // 42
console.log(c.sizeof(Example)); // 4

C equivalent — a plain struct with no padding between members when that is all you declare:

c
typedef struct {
    uint32_t value; /* c.field("u32") — 4 bytes; endian from c.read / c.write */
} Example;
  • c.read(ctor, bytes, endian?) — parse into a new instance (endian: "little" default or "big"). Slice the buffer first if the struct does not start at index 0.
  • c.write(ctor, instance, endian?) — serialize to a new Uint8Array.
  • c.sizeof(ctor) — total packed size in bytes (c.sizeof("u32") → 4 for primitives).
  • c.json(ctor, instance) — struct fields as a JSON-friendly object.

Read from an offset inside a larger buffer (file header + payload, chunk tables, etc.):

ts
const file = new Uint8Array([0, 0, 0, 0, 0, 0, 0, 42]);
const atEnd = c.read(Example, file.subarray(4), "big");

Next: Primitives & padding.