Arrays
Repeat a field a fixed number of times with the [N] suffix on a type string.
Primitive arrays
Append [N] to any integer or float type for a fixed inline array of N elements.
import { Struct } from '@remotex-labs/xstruct';
const s = new Struct<{ values: number[] }>({ values: 'u16le[4]' });
s.size; // 8, which is 4 elements of 2 bytes
s.toObject(s.toBuffer({ values: [ 1, 2, 3, 4 ] })).values; // [ 1, 2, 3, 4 ]A numeric type takes a single [N] dimension. The array passed to toBuffer should contain N elements.
String arrays
A fixed string takes two dimensions: encoding[byteCapacity][count]. The first bracket is the byte width of each element, the second is how many elements there are.
const codes = new Struct<{ list: string[] }>({ list: 'ascii[4][2]' });
// ^^^^ ^^^
// 4 bytes each, 2 elements
codes.toObject(codes.toBuffer({ list: [ 'ABCD', 'EFGH' ] })).list;
// [ 'ABCD', 'EFGH' ]See Strings.
Pointer arrays
Prefix with * for an array of pointers. Each slot addresses its own variable-length payload on the heap, so the elements need not be the same length.
const tags = new Struct<{ tags: string[] }>({ tags: '*utf8[3]' });
tags.toObject(tags.toBuffer({ tags: [ 'aa', 'bbbb', 'c' ] })).tags;
// [ 'aa', 'bbbb', 'c' ]The same form works for numeric pointers, for example '*u32le[4]' for four pointers, each to one heap u32le. See Heap & Pointers.
Sizing
A fixed array contributes N * elementSize to size. A pointer array contributes N * pointerSize to size; the payloads it references live in the heap region appended after the struct, so the buffer is larger than size.