+
−/*
+
− * This C module is the top level entity for our stateful decoder engine.
+
− */
+
−
+
−#include <stdint.h>
+
−#include <stdlib.h>
+
−#include <string.h>
+
−#include "tw_amr.h"
+
−#include "namespace.h"
+
−#include "typedef.h"
+
−#include "cnst.h"
+
−#include "dec_amr.h"
+
−#include "pstfilt.h"
+
−#include "post_pro.h"
+
−#include "bitno.h"
+
−
+
−struct amr_decoder_state {
+
−	Decoder_amrState	dec;
+
−	Post_FilterState	pstfilt;
+
−	Post_ProcessState	posthp;
+
−	enum Mode		prev_mode;
+
−	Flag			is_homed;
+
−};
+
−
+
−struct amr_decoder_state *amr_decoder_create(void)
+
−{
+
−	struct amr_decoder_state *st;
+
−
+
−	st = malloc(sizeof(struct amr_decoder_state));
+
−	if (st)
+
−		amr_decoder_reset(st);
+
−	return st;
+
−}
+
−
+
−void amr_decoder_reset(struct amr_decoder_state *st)
+
−{
+
−	Decoder_amr_reset(&st->dec, 0);
+
−	Post_Filter_reset(&st->pstfilt);
+
−	Post_Process_reset(&st->posthp);
+
−	st->prev_mode = (enum Mode) 0;
+
−	st->is_homed = 1;
+
−}
+
−
+
−void amr_decode_frame(struct amr_decoder_state *st,
+
−			const struct amr_param_frame *frame, int16_t *pcm)
+
−{
+
−	enum Mode mode;
+
−	Word16 parm[MAX_PRM_SIZE];
+
−	Word16 Az_dec[AZ_SIZE];
+
−	Word16 i;
+
−
+
−	/* fast home state handling needs to be first */
+
−	if (st->is_homed && amr_check_dhf(frame, 1)) {
+
−		for (i = 0; i < L_FRAME; i++)
+
−			pcm[i] = EHF_MASK;
+
−		return;
+
−	}
+
−	/* "unpack" into internal form */
+
−	if (frame->type == RX_NO_DATA)
+
−		mode = st->prev_mode;
+
−	else {
+
−		mode = frame->mode & 7;
+
−		st->prev_mode = mode;
+
−	}
+
−	memcpy(parm, frame->param, prmno[mode] * sizeof(int16_t));
+
−	/* now we can call the guts of the decoder */
+
−	Decoder_amr(&st->dec, mode, parm, frame->type, pcm, Az_dec);
+
−	Post_Filter(&st->pstfilt, mode, pcm, Az_dec);
+
−	Post_Process(&st->posthp, pcm, L_FRAME);
+
−	/*
+
−	 * The 3 lsbs of each speech sample typically won't be all 0
+
−	 * out of Post_Process(), hence we have to clear them explicitly
+
−	 * to maintain overall bit-exact operation.
+
−	 */
+
−	for (i = 0; i < L_FRAME; i++)
+
−		pcm[i] &= 0xFFF8;
+
−	/* final check for full DHF */
+
−	if (amr_check_dhf(frame, 0))
+
−		amr_decoder_reset(st);
+
−	else
+
−		st->is_homed = 0;
+
−}