anchor/ts/src/coder/spl-token/buffer-layout.ts

147 lines
3.5 KiB
TypeScript

import BN from "bn.js";
import * as BufferLayout from "buffer-layout";
import { Layout } from "buffer-layout";
import { PublicKey } from "@solana/web3.js";
import * as utils from "../../utils";
export function uint64(property?: string): Layout<u64 | null> {
return new WrappedLayout(
BufferLayout.blob(8),
(b: Buffer) => u64.fromBuffer(b),
(n: u64) => n.toBuffer(),
property
);
}
export function bool(property?: string): Layout<boolean> {
return new WrappedLayout(BufferLayout.u8(), decodeBool, encodeBool, property);
}
export function publicKey(property?: string): Layout<PublicKey> {
return new WrappedLayout(
BufferLayout.blob(32),
(b: Buffer) => new PublicKey(b),
(key: PublicKey) => key.toBuffer(),
property
);
}
export function coption<T>(
layout: Layout<T>,
property?: string
): Layout<T | null> {
return new COptionLayout<T>(layout, property);
}
class WrappedLayout<T, U> extends Layout<U> {
layout: Layout<T>;
decoder: (data: T) => U;
encoder: (src: U) => T;
constructor(
layout: Layout<T>,
decoder: (data: T) => U,
encoder: (src: U) => T,
property?: string
) {
super(layout.span, property);
this.layout = layout;
this.decoder = decoder;
this.encoder = encoder;
}
decode(b: Buffer, offset?: number): U {
return this.decoder(this.layout.decode(b, offset));
}
encode(src: U, b: Buffer, offset?: number): number {
return this.layout.encode(this.encoder(src), b, offset);
}
getSpan(b: Buffer, offset?: number): number {
return this.layout.getSpan(b, offset);
}
}
export class COptionLayout<T> extends Layout<T | null> {
layout: Layout<T>;
discriminator: Layout<number>;
constructor(layout: Layout<T>, property?: string) {
super(-1, property);
this.layout = layout;
this.discriminator = BufferLayout.u32();
}
encode(src: T | null, b: Buffer, offset = 0): number {
if (src === null || src === undefined) {
return this.layout.span + this.discriminator.encode(0, b, offset);
}
this.discriminator.encode(1, b, offset);
return this.layout.encode(src, b, offset + 4) + 4;
}
decode(b: Buffer, offset = 0): T | null {
const discriminator = this.discriminator.decode(b, offset);
if (discriminator === 0) {
return null;
} else if (discriminator === 1) {
return this.layout.decode(b, offset + 4);
}
throw new Error("Invalid coption " + this.property);
}
getSpan(b: Buffer, offset = 0): number {
return this.layout.getSpan(b, offset + 4) + 4;
}
}
function decodeBool(value: number): boolean {
if (value === 0) {
return false;
} else if (value === 1) {
return true;
}
throw new Error("Invalid bool: " + value);
}
function encodeBool(value: boolean): number {
return value ? 1 : 0;
}
export class u64 extends BN {
/**
* Convert to Buffer representation
*/
toBuffer(): Buffer {
const a = super.toArray().reverse();
const b = Buffer.from(a);
if (b.length === 8) {
return b;
}
if (b.length >= 8) {
throw new Error("u64 too large");
}
const zeroPad = Buffer.alloc(8);
b.copy(zeroPad);
return zeroPad;
}
/**
* Construct a u64 from Buffer representation
*/
static fromBuffer(buffer: Buffer): u64 {
if (buffer.length !== 8) {
throw new Error(`Invalid buffer length: ${buffer.length}`);
}
return new u64(
[...buffer]
.reverse()
.map((i) => `00${i.toString(16)}`.slice(-2))
.join(""),
16
);
}
}