Function parseCommandHeaders

packages/core/src/__tests__/drawlistDecode.ts:91–130

(bytes: Uint8Array)

}

export function parseCommandHeaders(bytes: Uint8Array): readonly DrawlistCommandHeader[] {
  const { cmdOffset, cmdEnd } = readCommandBounds(bytes);
  const out: DrawlistCommandHeader[] = [];

  let off = cmdOffset;
  while (off < cmdEnd) {
    const opcode = u16(bytes, off);
    const size = u32(bytes, off + 4);
    if (size < MIN_CMD_SIZE) {
      throw new Error(`command size below minimum at offset ${String(off)} (size=${String(size)})`);
    }
    if ((size & 3) !== 0) {
      throw new Error(
        `command size not 4-byte aligned at offset ${String(off)} (size=${String(size)})`,
      );
    }
    const next = off + size;
    if (next > cmdEnd) {
      throw new Error(
        `command overruns cmd section at offset ${String(off)} (size=${String(size)}, cmdEnd=${String(cmdEnd)})`,
      );
    }
    out.push({
      opcode,
      size,
      offset: off,
      payloadOffset: off + MIN_CMD_SIZE,
      payloadSize: size - MIN_CMD_SIZE,
    });
    off = next;
  }

  if (off !== cmdEnd) {
    throw new Error(
      `command parse did not end exactly at cmdEnd (off=${String(off)}, cmdEnd=${String(cmdEnd)})`,
    );
  }

  return Object.freeze(out);
}

function parseResourceState(bytes: Uint8Array): ResourceState {
  const headers = parseCommandHeaders(bytes);