feat: add RIFF container support

packages/scripts/src/core/blitz/parsePackedSpriteRect.ts

@@ -0,0 +1,53 @@
+const textDecoder = new TextDecoder();
+
+function readFourCC(buffer: Uint8Array, offset: number) {
+  return textDecoder.decode(buffer.subarray(offset, offset + 4));
+}
+
+export function parsePackedSpriteRect(buffer: Uint8Array): number[] | null {
+  if (
+    buffer.length < 12 ||
+    readFourCC(buffer, 0) !== "RIFF" ||
+    readFourCC(buffer, 8) !== "WEBP"
+  ) {
+    return null;
+  }
+
+  const view = new DataView(
+    buffer.buffer,
+    buffer.byteOffset,
+    buffer.byteLength,
+  );
+  let offset = 12;
+
+  while (offset + 8 <= buffer.length) {
+    const chunkId = readFourCC(buffer, offset);
+    const chunkSize = view.getUint32(offset + 4, true);
+    const dataStart = offset + 8;
+    const dataEnd = dataStart + chunkSize;
+
+    if (dataEnd > buffer.length) return null;
+
+    if (chunkId === "extr") {
+      const lines = textDecoder
+        .decode(buffer.subarray(dataStart, dataEnd))
+        .replace(/\0/g, "")
+        .split(/\r?\n/)
+        .map((line) => line.trim().split(/\s+/).map(Number));
+
+      for (const values of lines) {
+        if (values.length < 4) continue;
+        if (!values.slice(0, 4).every(Number.isFinite)) continue;
+        if (values[2] <= 0 || values[3] <= 0) continue;
+
+        return values;
+      }
+
+      return null;
+    }
+
+    offset = dataEnd + (chunkSize % 2);
+  }
+
+  return null;
+}