feat: migration 2

packages/core/src/streams/dids.ts

@@ -0,0 +1,51 @@
+import { times } from 'lodash';
+import { ReadStream, WriteStream } from './buffer';
+
+export class DidsReadStream extends ReadStream {
+  dids() {
+    this.magic();
+    this.header();
+    return this.body();
+  }
+
+  magic() {
+    const magic = this.utf8(4);
+    if (magic !== 'DIDS') {
+      throw new Error(`Invalid DIDS magic number: "${magic}"`);
+    }
+  }
+
+  header() {
+    return {
+      version: this.uint16(),
+    };
+  }
+
+  body() {
+    const count = this.uint32();
+    return times(count, () => this.uint32());
+  }
+}
+
+export class DidsWriteStream extends WriteStream {
+  dids(ids: number[]) {
+    this.magic();
+    this.header();
+    this.body(ids);
+
+    return this;
+  }
+
+  magic() {
+    this.utf8('DIDS');
+  }
+
+  header() {
+    this.uint16(1);
+  }
+
+  body(ids: number[]) {
+    this.uint32(ids.length);
+    ids.forEach((id) => this.uint32(id));
+  }
+}