--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtwamr/g_adapt.h	Mon May 06 03:01:15 2024 +0000
@@ -0,0 +1,73 @@
+/*
+********************************************************************************
+*
+*      GSM AMR-NB speech codec   R98   Version 7.6.0   December 12, 2001
+*                                R99   Version 3.3.0                
+*                                REL-4 Version 4.1.0                
+*
+********************************************************************************
+*
+*      File             : g_adapt.h
+*      Purpose          : gain adaptation for MR795 gain quantization
+*
+********************************************************************************
+*/
+
+/*
+********************************************************************************
+*                         MODULE INCLUDE FILE AND VERSION ID
+********************************************************************************
+*/
+#ifndef g_adapt_h
+#define g_adapt_h "$Id $"
+
+/*
+********************************************************************************
+*                         INCLUDE FILES
+********************************************************************************
+*/
+#include "typedef.h"
+
+#define LTPG_MEM_SIZE 5 /* number of stored past LTP coding gains + 1 */
+
+/*
+********************************************************************************
+*                         DEFINITION OF DATA TYPES
+********************************************************************************
+*/
+typedef struct {
+    Word16 onset;                   /* onset state,                   Q0  */
+    Word16 prev_alpha;              /* previous adaptor output,       Q15 */
+    Word16 prev_gc;                 /* previous code gain,            Q1  */
+
+    Word16 ltpg_mem[LTPG_MEM_SIZE]; /* LTP coding gain history,       Q13 */
+                                    /* (ltpg_mem[0] not used for history) */
+} GainAdaptState;
+ 
+/*
+********************************************************************************
+*                         DECLARATION OF PROTOTYPES
+********************************************************************************
+*/
+ 
+void gain_adapt_reset (GainAdaptState *st);
+/* reset of gain adaptor state (i.e. set state memory to zero)
+   returns 0 on success
+ */
+
+/*************************************************************************
+ *
+ *  Function:   gain_adapt()
+ *  Purpose:    calculate pitch/codebook gain adaptation factor alpha
+ *              (and update the adaptor state)
+ *
+ **************************************************************************
+ */
+void gain_adapt(
+    GainAdaptState *st,  /* i  : state struct                  */
+    Word16 ltpg,         /* i  : ltp coding gain (log2()), Q   */
+    Word16 gain_cod,     /* i  : code gain,                Q13 */
+    Word16 *alpha        /* o  : gain adaptation factor,   Q15 */
+);
+
+#endif