add fromUpdateDeckPayload

README.md

@@ -23,6 +23,10 @@ const ygomobileDeckUrl = deck.toYGOMobileDeckURL(); // YGOMobile Deck URL
 const yetAnotherDeck3 = YGOProDeck.fromYGOMobileDeckURL(ygomobileDeckUrl); // decode it back
 
 const updateDeckPayload = deck.toUpdateDeckPayload(); // payload for MSG_UPDATE_DECK
+// decode it back, but a callback is needed for check if it's extra deck
+// use SQLite3 is recommended
+// by default, it would assume everything is main deck
+const yetAnotherDeck4 = YGOProDeck.fromUpdateDeckPayload(updateDeckPayload, (code, i, mainc) => i >= mainc - 15);
 ```
 
 

index.ts

 import { fromBase64Url, toBase64Url } from './src/base64';
-import { BufferWriter, countItems } from './src/utils';
+import { BufferReader, BufferWriter, countItems } from './src/utils';
 import { fromYdkeURL, toYdkeURL } from './src/ydke';
 import { fromYGOMobileDeckURL, toYGOMobileDeckURL } from './src/ygom';
 
@@ -105,6 +105,32 @@ export default class YGOProDeck {
     return new YGOProDeck().fromYdkString(str);
   }
 
+  fromUpdateDeckPayload(buf: Uint8Array, isExtraDeckCard: (code: number, i: number, mainc: number) => boolean = () => false) {
+    const reader = new BufferReader(buf);
+    const mainc = reader.readUint32LE();
+    const sidec = reader.readUint32LE();
+    this.main = [];
+    this.extra = [];
+    this.side = [];
+    for(let i = 0; i < mainc; i++) {
+      const id = reader.readUint32LE();
+      if (isExtraDeckCard(id, i, mainc)) {
+        this.extra.push(id);
+      } else {
+        this.main.push(id);
+      }
+    }
+    for(let i = 0; i < sidec; i++) {
+      const id = reader.readUint32LE();
+      this.side.push(id);
+    }
+    return this;
+  }
+
+  static fromUpdateDeckPayload(buf: Uint8Array, isExtraDeckCard: (code: number) => boolean = () => false) { 
+    return new YGOProDeck().fromUpdateDeckPayload(buf, isExtraDeckCard);
+  }
+
   toUpdateDeckPayload() {
     const cards = [...this.main, ...this.extra, ...this.side];
     const writer = new BufferWriter(cards.length * 4 + 8)

src/utils.ts

@@ -5,50 +5,146 @@ export function countItems<T>(arr: T[]) {
   }
   return map;
 }
-
-export class BufferWriter {
+abstract class BufferCursor {
   buffer: Uint8Array;
   pointer = 0;
+
+  constructor(bufOrLength: Uint8Array | number) {
+    if (typeof bufOrLength === 'number') {
+      this.buffer = new Uint8Array(bufOrLength);
+    } else {
+      this.buffer = bufOrLength;
+    }
+  }
+
+  /**
+   * 安全地将 pointer 向前移动指定字节数。
+   * @param bytes 要移动的字节数
+   * @returns 原来 pointer 的值
+   * @throws RangeError 如果越界
+   */
+  protected increasePointer(bytes: number): number {
+    const old = this.pointer;
+    const next = old + bytes;
+    if (next > this.buffer.length) {
+      throw new RangeError(
+        `Pointer overflow: tried to move to ${next}, but buffer length is ${this.buffer.length}`
+      );
+    }
+    this.pointer = next;
+    return old;
+  }
+}
+
+export class BufferWriter extends BufferCursor {
   constructor(length: number) {
-    this.buffer = new Uint8Array(length);
+    super(length);
   }
+
   writeUint32LE(value: number) {
-    this.buffer[this.pointer++] = value & 0xff;
-    this.buffer[this.pointer++] = (value >>> 8) & 0xff;
-    this.buffer[this.pointer++] = (value >>> 16) & 0xff;
-    this.buffer[this.pointer++] = (value >>> 24) & 0xff;
+    const idx = this.increasePointer(4);
+    this.buffer[idx    ] =  value         & 0xff;
+    this.buffer[idx + 1] = (value >>> 8)  & 0xff;
+    this.buffer[idx + 2] = (value >>> 16) & 0xff;
+    this.buffer[idx + 3] = (value >>> 24) & 0xff;
     return this;
   }
 
   writeUint32BE(value: number) {
-    this.buffer[this.pointer++] = (value >>> 24) & 0xff;
-    this.buffer[this.pointer++] = (value >>> 16) & 0xff;
-    this.buffer[this.pointer++] = (value >>> 8) & 0xff;
-    this.buffer[this.pointer++] = value & 0xff;
+    const idx = this.increasePointer(4);
+    this.buffer[idx    ] = (value >>> 24) & 0xff;
+    this.buffer[idx + 1] = (value >>> 16) & 0xff;
+    this.buffer[idx + 2] = (value >>> 8)  & 0xff;
+    this.buffer[idx + 3] =  value         & 0xff;
     return this;
   }
 
   writeUint16LE(value: number) {
-    this.buffer[this.pointer++] = value & 0xff;
-    this.buffer[this.pointer++] = (value >>> 8) & 0xff;
+    const idx = this.increasePointer(2);
+    this.buffer[idx    ] =  value        & 0xff;
+    this.buffer[idx + 1] = (value >>> 8) & 0xff;
     return this;
   }
 
   writeUint16BE(value: number) {
-    this.buffer[this.pointer++] = (value >>> 8) & 0xff;
-    this.buffer[this.pointer++] = value & 0xff;
+    const idx = this.increasePointer(2);
+    this.buffer[idx    ] = (value >>> 8) & 0xff;
+    this.buffer[idx + 1] =  value        & 0xff;
     return this;
   }
 
   writeUint8(value: number) {
-    this.buffer[this.pointer++] = value & 0xff;
+    const idx = this.increasePointer(1);
+    this.buffer[idx] = value & 0xff;
     return this;
   }
 
   writeString(str: string) {
     for (let i = 0; i < str.length; i++) {
-      this.buffer[this.pointer++] = str.charCodeAt(i);
+      const idx = this.increasePointer(1);
+      this.buffer[idx] = str.charCodeAt(i);
     }
     return this;
   }
 }
+
+export class BufferReader extends BufferCursor {
+  constructor(buf: Uint8Array) {
+    super(buf);
+  }
+
+  readUint32LE(): number {
+    const idx = this.increasePointer(4);
+    const b = this.buffer;
+    // >>>0 保证无符号输出
+    return (
+      (b[idx    ]      ) |
+      (b[idx + 1] <<  8) |
+      (b[idx + 2] << 16) |
+      (b[idx + 3] << 24)
+    ) >>> 0;
+  }
+
+  readUint32BE(): number {
+    const idx = this.increasePointer(4);
+    const b = this.buffer;
+    return (
+      (b[idx    ] << 24) |
+      (b[idx + 1] << 16) |
+      (b[idx + 2] <<  8) |
+      (b[idx + 3]      )
+    ) >>> 0;
+  }
+
+  readUint16LE(): number {
+    const idx = this.increasePointer(2);
+    const b = this.buffer;
+    return (b[idx] | (b[idx + 1] << 8));
+  }
+
+  readUint16BE(): number {
+    const idx = this.increasePointer(2);
+    const b = this.buffer;
+    return ((b[idx] << 8) | b[idx + 1]);
+  }
+
+  readUint8(): number {
+    const idx = this.increasePointer(1);
+    return this.buffer[idx];
+  }
+
+  readString(length: number): string {
+    let s = '';
+    for (let i = 0; i < length; i++) {
+      const idx = this.increasePointer(1);
+      s += String.fromCharCode(this.buffer[idx]);
+    }
+    return s;
+  }
+
+  readRemaining(): Uint8Array {
+    const remaining = this.buffer.length - this.pointer;
+    const idx = this.increasePointer(remaining);
+    return this.buffer.subarray(idx, this.buffer.length);
+  }
+}

tests/sample.spec.ts

 import YGOProDeck from '..';
+import { BufferReader } from '../src/utils';
 
 const deck = new YGOProDeck();
 deck.main.push(123);
@@ -86,4 +87,22 @@ describe('Sample test.', () => {
     expect(decoded.extra).toStrictEqual(deck.extra);
     expect(decoded.side).toStrictEqual(deck.side);
   });
+
+  it('should encode and decode update deck payload', () => {
+    const uri = 'http://deck.ourygo.top?name=%E7%99%BD%E9%93%B6%E5%9F%8E%E7%A0%81&ygotype=deck&v=1&d=J-xK4Mka02AuEAMf2dV6mj7aRemuJNQJK8BwrcEYh0MqOJqBJSgYqUwxPEVhOG8R18WWVKmzkT-xEdwxbmGVkkOdrVIpufaYI3Hs8oOrcya8Bi40h9G79iFW80rq-o6P-AHsusPY5nmvHLol0DIqEykESVlf6VSbxVJp-j7XZtTE0XvmJW80rqH28R4rgyRovOusVJzbutenYFBA_cyK6d3UWcQkJQlLjaroWavH-INFA56k5DQNWOQ1gpvxrKVBLgEk1olpolKmSgriramLlgtBK1EQ6C6oi94ZyHe7N6T7mqE6peds7mahrORP6A';
+    const deck = new YGOProDeck().fromYGOMobileDeckURL(uri);
+    const updateDeckPayload = deck.toUpdateDeckPayload();
+    const bufferReader = new BufferReader(updateDeckPayload);
+    const mainc = bufferReader.readUint32LE();
+    const sidec = bufferReader.readUint32LE();
+    expect(mainc).toBe(58 + 15);
+    expect(sidec).toBe(15);
+    const deckAgain = new YGOProDeck().fromUpdateDeckPayload(updateDeckPayload, (id, i, mainc) => i >= 58);
+    expect(deckAgain.main).toHaveLength(58);
+    expect(deckAgain.extra).toHaveLength(15);
+    expect(deckAgain.side).toHaveLength(15);
+    expect(deckAgain.main).toStrictEqual(deck.main);
+    expect(deckAgain.extra).toStrictEqual(deck.extra);
+    expect(deckAgain.side).toStrictEqual(deck.side);
+  })
 });