feat: new sharing system

feat: support legacy layout import

src/lib/share/action-array.ts

@@ -0,0 +1,52 @@
+import {compressActions, decompressActions} from "$lib/serialization/actions"
+import {CHARA_FILE_TYPES} from "$lib/share/share-url"
+
+export type ActionArray = number[] | ActionArray[]
+export function serializeActionArray(array: ActionArray): Uint8Array {
+  let out = new Uint8Array(5)
+  const writer = new DataView(out.buffer)
+  writer.setUint32(0, array.length)
+
+  if (array.length === 0) {
+    return out
+  } else if (typeof array[0] === "number") {
+    writer.setUint8(4, CHARA_FILE_TYPES.indexOf("number"))
+    return concatUint8Arrays(out, compressActions(array as number[]))
+  } else if (Array.isArray(array[0])) {
+    writer.setUint8(4, CHARA_FILE_TYPES.indexOf("array"))
+    return concatUint8Arrays(out, ...(array as ActionArray[]).map(serializeActionArray))
+  } else {
+    throw new Error("Not implemented")
+  }
+}
+
+export function deserializeActionArray(raw: Uint8Array): ActionArray {
+  const reader = new DataView(raw.buffer)
+  const length = reader.getUint32(0)
+  const type = CHARA_FILE_TYPES[reader.getUint8(4)]
+
+  if (type === "number") {
+    return decompressActions(raw.slice(5, 5 + length))
+  } else if (type === "array") {
+    const innerLength = reader.getUint32(5)
+    const out = []
+    let cursor = 5
+    for (let i = 0; i < length; i++) {
+      out.push(deserializeActionArray(raw.slice(cursor, cursor + innerLength)))
+      cursor += innerLength
+    }
+    return out
+  } else {
+    throw new Error("Not implemented")
+  }
+}
+
+export function concatUint8Arrays(...arrays: Uint8Array[]): Uint8Array {
+  const out = new Uint8Array(arrays.reduce((a, b) => a + b.length, 0))
+  let offset = 0
+  for (const array of arrays) {
+    out.set(array, offset)
+    offset += array.length
+  }
+  return out
+}