/***********************************************************************************      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             : lpc.h*      Purpose          : 2 LP analyses centered at 2nd and 4th subframe*                         for mode 12.2. For all other modes a*                         LP analysis centered at 4th subframe is *                         performed.**********************************************************************************/#ifndef lpc_h#define lpc_h "$Id $"/**********************************************************************************                         INCLUDE FILES*********************************************************************************/#include "typedef.h"#include "levinson.h"#include "mode.h"/**********************************************************************************                         LOCAL VARIABLES AND TABLES*********************************************************************************//**********************************************************************************                         DEFINITION OF DATA TYPES*********************************************************************************/typedef struct {   LevinsonState *levinsonSt;} lpcState;/**********************************************************************************                         DECLARATION OF PROTOTYPES*********************************************************************************/int lpc_init (lpcState **st);/* initialize one instance of the pre processing state.   Stores pointer to filter status struct in *st. This pointer has to   be passed to lpc in each call.   returns 0 on success */ int lpc_reset (lpcState *st);/* reset of pre processing state (i.e. set state memory to zero)   returns 0 on success */void lpc_exit (lpcState **st);/* de-initialize pre processing state (i.e. free status struct)   stores NULL in *st */int lpc(    lpcState *st,     /* i/o: State struct                */    enum Mode mode,   /* i  : coder mode                  */    Word16 x[],       /* i  : Input signal           Q15  */    Word16 x_12k2[],  /* i  : Input signal (EFR)     Q15  */    Word16 a[]        /* o  : predictor coefficients Q12  */);#endif