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PSON decoder example using namespaced imports
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‎README.md‎

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[![Build Status](https://travis-ci.org/AssemblyScript/assemblyscript.svg?branch=master)](https://travis-ci.org/AssemblyScript/assemblyscript)
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**AssemblyScript** compiles strictly typed [TypeScript](http://www.typescriptlang.org) to [WebAssembly](http://webassembly.org) using [Binaryen](https://github.com/WebAssembly/binaryen). Unlike more complex toolchains, `asc` generates minimal WebAssembly modules while being just an `npm install` away.
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**AssemblyScript** compiles strictly typed [TypeScript](http://www.typescriptlang.org) to [WebAssembly](http://webassembly.org) using [Binaryen](https://github.com/WebAssembly/binaryen). Unlike other toolchains, `asc` generates minimal WebAssembly modules while being just an `npm install` away.
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Examples
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--------
@@ -16,6 +16,9 @@ A few early examples to get an idea:
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* **[i64 polyfill](./examples/i64-polyfill)**<br />
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Exposes WebAssembly's i64 operations to JavaScript using 32-bit integers (low and high bits).
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* **[PSON decoder](./examples/pson)**<br />
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A PSON decoder implemented in AssemblyScript.
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Or browse the [compiler tests](./tests/compiler) for a more in-depth overview of what's supported already.
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Getting started

‎examples/.gitignore‎

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*.wast
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*.wasm
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node_modules/
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npm-debug.log
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package-lock.json

‎examples/game-of-life/assembly/game-of-life.ts‎

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// A simplified version of the game of life as seen on http://dcode.io
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var w: u32; // width
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var h: u32; // height
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var s: u32; // total size
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var w: u32, // width
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h: u32, // height
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s: u32; // total size
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/** Initializes width and height. */
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export function init(w_: u32, h_: u32): void {
@@ -13,21 +13,18 @@ export function init(w_: u32, h_: u32): void {
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/** Performs one step. */
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export function step(): void {
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var y: u32, ym1: u32, yp1: u32; // y, y-1 and y+1
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var x: u32, xm1: u32, xp1: u32; // x, x-1 and x+1
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var hm1: u32 = h - 1, wm1: u32 = w - 1;
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var n: u32, v: u8, c: u32 = 0;
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for (y = 0; y < h; ++y) {
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ym1 = select<u32>(hm1, y - 1, y == 0);
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yp1 = select<u32>(0, y + 1, y == hm1);
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for (x = 0; x < w; ++x) {
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xm1 = select<u32>(wm1, x - 1, x == 0);
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xp1 = select<u32>(0, x + 1, x == wm1);
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n = load<u8>(ym1 * w + xm1) + load<u8>(ym1 * w + x) + load<u8>(ym1 * w + xp1)
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+ load<u8>(y * w + xm1) + load<u8>(y * w + xp1)
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+ load<u8>(yp1 * w + xm1) + load<u8>(yp1 * w + x) + load<u8>(yp1 * w + xp1);
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v = load<u8>(y * w + x);
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if (v) {
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var hm1 = h - 1,
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wm1 = w - 1;
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for (var y: u32 = 0; y < h; ++y) {
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var ym1 = select<u32>(hm1, y - 1, y == 0),
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yp1 = select<u32>(0, y + 1, y == hm1);
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for (var x: u32 = 0; x < w; ++x) {
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var xm1 = select<u32>(wm1, x - 1, x == 0),
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xp1 = select<u32>(0, x + 1, x == wm1);
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var n = load<u8>(ym1 * w + xm1) + load<u8>(ym1 * w + x) + load<u8>(ym1 * w + xp1)
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+ load<u8>(y * w + xm1) + load<u8>(y * w + xp1)
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+ load<u8>(yp1 * w + xm1) + load<u8>(yp1 * w + x) + load<u8>(yp1 * w + xp1);
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if (load<u8>(y * w + x)) {
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if (n < 2 || n > 3)
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store<u8>(s + y * w + x, 0);
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} else if (n == 3)

‎examples/i64-polyfill/assembly/i64.ts‎

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let lo: u32;
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let hi: u32;
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var lo: u32,
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hi: u32;
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export function getLo(): u32 {
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return lo;

‎examples/pson/README.md‎

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PSON decoder in WebAssembly
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===========================
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An [AssemblyScript](http://assemblyscript.org) example. Decodes a [PSON](https://github.com/dcodeIO/PSON) encoded buffer.
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Instructions
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------------
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To build [assembly/pson.ts](./assembly/pson.ts) to an untouched and an optimized `.wasm` including their respective `.wast` representations, run:
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```
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$> npm run build
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```
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Afterwards, to run the included test, do:
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```
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$> npm test
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```

‎examples/pson/assembly/pson.ts‎

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const enum Token {
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ZERO = 0x00,
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MAX = 0xEF,
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NULL = 0xf0,
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TRUE = 0xf1,
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FALSE = 0xf2,
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EOBJECT = 0xf3,
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EARRAY = 0xf4,
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ESTRING = 0xf5,
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OBJECT = 0xf6,
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ARRAY = 0xf7,
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INTEGER = 0xf8,
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LONG = 0xf9,
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FLOAT = 0xfa,
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DOUBLE = 0xfb,
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STRING = 0xfc,
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STRING_ADD = 0xfd,
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STRING_GET = 0xfe,
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BINARY = 0xff
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}
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namespace pson {
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export declare function onNull(): void;
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export declare function onTrue(): void;
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export declare function onFalse(): void;
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export declare function onEObject(): void;
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export declare function onEArray(): void;
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export declare function onEString(): void;
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export declare function onObject(size: u32): void;
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export declare function onArray(size: u32): void;
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export declare function onInteger(value: i32): void;
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export declare function onLong(valueLow: i32, valueHigh: i32): void;
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export declare function onFloat(value: f32): void;
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export declare function onDouble(value: f64): void;
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export declare function onString(offset: usize, length: u32): void;
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export declare function onBinary(offset: usize, length: u32): void;
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export declare function onTruncated(): void;
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}
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var offset: usize = 0;
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export function decode(length: usize): void {
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offset = 0;
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while (offset < length)
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decodeValue();
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if (offset != length)
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pson.onTruncated();
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}
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function decodeValue(): void {
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var token: u32 = load<u8>(offset++);
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var size: u32;
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var long: u64;
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switch (token) {
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case Token.NULL:
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pson.onNull();
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break;
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case Token.TRUE:
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pson.onTrue();
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break;
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case Token.FALSE:
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pson.onFalse();
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break;
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case Token.EOBJECT:
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pson.onEObject();
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break;
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case Token.EARRAY:
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pson.onEArray();
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break;
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case Token.ESTRING:
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pson.onEString();
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break;
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case Token.OBJECT:
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pson.onObject(size = readVarint32());
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while (size--) {
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decodeValue();
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decodeValue();
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}
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break;
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case Token.ARRAY:
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pson.onArray(size = readVarint32());
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while (size--)
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decodeValue();
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break;
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case Token.INTEGER:
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pson.onInteger(((size = readVarint32()) >> 1) ^ -(size & 1));
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break;
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case Token.LONG:
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long = ((long = readVarint64()) >> 1) ^ -(long & 1);
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pson.onLong(<i32>long, <i32>(long >>> 32));
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break;
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case Token.FLOAT:
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pson.onFloat(load<f32>(offset));
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offset += 4;
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break;
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case Token.DOUBLE:
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pson.onDouble(load<f64>(offset));
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offset += 8;
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break;
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case Token.STRING:
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size = readVarint32();
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pson.onString(offset, size);
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offset += size;
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break;
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case Token.STRING_ADD:
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case Token.STRING_GET:
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// could be implemented via imports as well, but isn't necessary for this example
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throw new Error("not implemented");
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case Token.BINARY:
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size = readVarint32();
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pson.onBinary(offset, size);
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offset += size;
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break;
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default: // small integer?
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if (token > Token.MAX)
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throw new Error("unexpected token");
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pson.onInteger((token >> 1) ^ -(token & 1));
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break;
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}
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}
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function readVarint32(): u32 {
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var value: u32 = 0;
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var shift: u32 = 0;
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do {
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var b = load<u8>(offset++);
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value |= <u32>(b & 0x7f) << (7 * shift++);
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} while (b & 0x80);
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return value;
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}
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function readVarint64(): u64 {
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var value: u64 = 0;
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var shift: u64 = 0;
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do {
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var b = load<u8>(offset++);
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value |= <u64>(b & 0x7f) << (7 * shift++);
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} while (b & 0x80);
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return value;
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}

‎examples/pson/assembly/tsconfig.json‎

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{
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"extends": "../../../std/assembly.json",
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"include": [
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"./**/*.ts"
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]
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}

‎examples/pson/index.js‎

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var fs = require("fs");
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// Define imports. Just logs to console for the sake of this example.
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var pson = {
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onNull: function() {
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console.log("null");
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},
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onTrue: function() {
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console.log("true");
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},
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onFalse: function() {
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console.log("false");
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},
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onEObject: function() {
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console.log("{}");
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},
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onEArray: function() {
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console.log("[]");
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},
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onEString: function() {
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console.log("\"\"");
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},
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onObject: function(size) {
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console.log("{" + size + "}")
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},
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onArray: function(size) {
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console.log("[" + size + "]");
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},
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onInteger: function(value) {
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console.log("integer: " + value);
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},
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onLong: function(valueLow, valueHigh) {
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console.log("long: " + valueLow + ", " + valueHigh);
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},
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onFloat: function(value) {
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console.log("float: " + value);
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},
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onDouble: function(value) {
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console.log("double: " + value);
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},
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onString: function(offset, length) {
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console.log("string(length=" + length + "): " + new Buffer(mem.slice(offset, offset + length)).toString());
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},
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onBinary: function(offset, length) {
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console.log("binary(length=" + length + "): " + mem.slice(offset, offset + length));
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},
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onTruncated: function() {
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console.log("buffer is truncated :-(");
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}
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};
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// Instantiate the module
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var mod = new WebAssembly.Module(fs.readFileSync(__dirname + "/pson.optimized.wasm"));
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var ins = new WebAssembly.Instance(mod, { pson: pson });
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var mem = new Uint8Array(ins.exports.memory.buffer);
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// Export API
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exports.decode = function(buffer) {
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// grow memory if necessary
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if (mem.length < buffer.length) {
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ins.exports.memory.grow(Math.ceil((buffer.length - mem.length) / 65536));
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mem = new Uint8Array(ins.exports.memory.buffer);
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}
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// copy buffer to memory
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mem.set(buffer);
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// start decoding (calls the imports defined above)
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ins.exports.decode(buffer.length);
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}

‎examples/pson/package.json‎

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{
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"name": "@assemblyscript/pson-example",
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"version": "1.0.0",
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"private": true,
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"scripts": {
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"build": "npm run build:untouched && npm run build:optimized",
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"build:untouched": "asc assembly/pson.ts -b pson.untouched.wasm -t pson.untouched.wast --validate",
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"build:optimized": "asc -O assembly/pson.ts -b pson.optimized.wasm -t pson.optimized.wast --validate",
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"test": "node tests"
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},
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"devDependencies": {
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"pson": "^2.0.0"
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}
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}

‎examples/pson/tests/index.js‎

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var Long = require("long");
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var psonJS = require("pson");
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var psonWASM = require("..");
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// encode in JS
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var buf = new psonJS.Encoder().encode({
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emptyObject: {},
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emptyArray: [],
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emptyString: "",
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object: {
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aSmallInt: 42,
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anInt: 9000,
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aLong: Long.MIN_VALUE.add(1)
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},
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array: [
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0.25, // fits into float
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0.1 // always a double
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],
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binary: Buffer.from([1, 2, 3])
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}).toBuffer();
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// decode in WASM
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psonWASM.decode(buf);

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