More improvements to the XMA decoder (and included some forgotten files)

src/xenia/apu/xma_helpers.h

@@ -0,0 +1,43 @@
+/**
+******************************************************************************
+* Xenia : Xbox 360 Emulator Research Project                                 *
+******************************************************************************
+* Copyright 2015 Ben Vanik. All rights reserved.                             *
+* Released under the BSD license - see LICENSE in the root for more details. *
+******************************************************************************
+*/
+
+// This file contains some functions used to help parse XMA data.
+
+#ifndef XENIA_APU_XMA_HELPERS_H_
+#define XENIA_APU_XMA_HELPERS_H_
+
+#include <stdint.h>
+
+namespace xe {
+namespace apu {
+namespace xma {
+
+// Get number of frames that /begin/ in this packet.
+uint32_t GetPacketFrameCount(uint8_t* packet) {
+  return (uint8_t)(packet[0] >> 2);
+}
+
+// Get the first frame offset in bits
+uint32_t GetPacketFrameOffset(uint8_t* packet) {
+  return (uint16_t)((packet[0] << 13) | (packet[1] << 5) | (packet[2] >> 3)) + 32;
+}
+
+uint32_t GetPacketMetadata(uint8_t* packet) {
+  return (uint8_t)(packet[2] & 0x7);
+}
+
+uint32_t GetPacketSkipCount(uint8_t* packet) {
+  return (uint8_t)(packet[3]);
+}
+
+} // namespace xma
+} // namespace apu
+} // namespace xe
+
+#endif  // XENIA_APU_XMA_HELPERS_H_