Split libacm files to third_party/libacm and AudioEncode

Logically adecode/aencode belongs to AudioEncode.

AudioEncode/adecode.h

@@ -0,0 +1,51 @@
+/*
+ * Descent 3
+ * Copyright (C) 2024 Parallax Software
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef AUDIODECODE_H_
+#define AUDIODECODE_H_
+
+#include <cstdint>
+
+namespace AudioDecoder {
+
+class IAudioDecoder {
+public:
+  virtual ~IAudioDecoder() {}
+
+  // Read data from the audio decoder.
+  //   pBuffer: The buffer to receive the data from
+  //    amount: How much data to read
+  // Returns the number of bytes read - zero when we're at the end of the file
+  virtual uint32_t Read(void *pBuffer, uint32_t amount) = 0;
+};
+
+// Create an audio decoder
+// You supply a function for reading bytes from the compressed data via a
+// void* pData handle, and the handle itself (typically a FILE *).
+// Create_AudioDecoder returns a new AudioDecoder which can be used to
+// read uncompressed decoded data from the compressed stream,
+// and also returns the number of channels (1 or 2), the sample rate
+// (e.g. 22050), and the number of samples contained in the compressed file
+// (in case you want to pre-allocate a buffer to load them all into memory).
+typedef int32_t (*ReadDataFunction)(void *pData, void *pBuffer, uint32_t amount);
+IAudioDecoder *CreateDecoder(ReadDataFunction reader, void *pData, uint32_t &numChannels, uint32_t &sampleRate,
+                             uint32_t &sampleCount);
+
+} // namespace AudioDecoder
+
+#endif