import { Codec, createCodec, metadata } from "../common/mod.ts"
export const u8 = createCodec<number>({ _metadata: intMetadata(false, 8), _staticSize: 1, _encode(buffer, value) { buffer.array[buffer.index++] = value }, _decode(buffer) { return buffer.array[buffer.index++]! }, _assert(assert) { assert.integer(this, 0, 255) },})
function _intNumber(signed: boolean, size: 8 | 16 | 32): Codec<number> { const byteSize = size / 8 const key = `${(signed ? "Int" : "Uint")}${size}` as const const getMethod = DataView.prototype[`get${key}`] const setMethod = DataView.prototype[`set${key}`] const min = signed ? -(2 ** (size - 1)) : 0 const max = (2 ** (size - +signed)) - 1 return createCodec({ _metadata: intMetadata(signed, size), _staticSize: byteSize, _encode(buffer, value) { setMethod.call(buffer.view, buffer.index, value, true) buffer.index += byteSize }, _decode(buffer) { const value = getMethod.call(buffer.view, buffer.index, true) buffer.index += byteSize return value }, _assert(assert) { assert.typeof(this, "number") assert.integer(this, min, max) }, })}
export const i8 = _intNumber(true, 8)export const u16 = _intNumber(false, 16)export const i16 = _intNumber(true, 16)export const u32 = _intNumber(false, 32)export const i32 = _intNumber(true, 32)
function _intBigInt(signed: boolean, size: 64 | 128 | 256): Codec<bigint> { const byteSize = size / 8 const chunks = size / 64 const getMethod = DataView.prototype[signed ? "getBigInt64" : "getBigUint64"] const min = signed ? -(1n << BigInt(size - 1)) : 0n const max = (1n << BigInt(size - +signed)) - 1n return createCodec({ _metadata: intMetadata(signed, size), _staticSize: byteSize, _encode(buffer, value) { for (let i = 0; i < chunks; i++) { buffer.view.setBigInt64(buffer.index, value, true) value >>= 64n buffer.index += 8 } }, _decode(buffer) { let value = getMethod.call(buffer.view, buffer.index + (byteSize - 8), true) for (let i = chunks - 2; i >= 0; i--) { value <<= 64n value |= buffer.view.getBigUint64(buffer.index + (i * 8), true) } buffer.index += byteSize return value }, _assert(assert) { assert.bigint(this, min, max) }, })}
export const u64 = _intBigInt(false, 64)export const i64 = _intBigInt(true, 64)export const u128 = _intBigInt(false, 128)export const i128 = _intBigInt(true, 128)export const u256 = _intBigInt(false, 256)export const i256 = _intBigInt(true, 256)
const intLookup = { u8, i8, u16, i16, u32, i32, u64, i64, u128, i128, u256, i256 }
export function int(signed: boolean, size: 8 | 16 | 32): Codec<number>export function int(signed: boolean, size: 64 | 128 | 256): Codec<bigint>export function int(signed: boolean, size: 8 | 16 | 32 | 64 | 128 | 256): Codec<number> | Codec<bigint>export function int(signed: boolean, size: 8 | 16 | 32 | 64 | 128 | 256): Codec<number | bigint>export function int(signed: boolean, size: 8 | 16 | 32 | 64 | 128 | 256): Codec<any> { const key = `${signed ? "i" : "u"}${size}` as const return intLookup[key]}
function intMetadata<T extends number | bigint>(signed: boolean, size: number) { return metadata<T, T>( metadata(`$.${signed ? "i" : "u"}${size}`), metadata("$.int", int as any, signed, size), )}