/*---------------------------------------------------------------------------*\

  FILE........: c2dec.c
  AUTHOR......: David Rowe
  DATE CREATED: 23/8/2010

  Decodes a file of bits to a file of raw speech samples using codec2.

\*---------------------------------------------------------------------------*/

/*
  Copyright (C) 2010 David Rowe

  All rights reserved.

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License version 2.1, as
  published by the Free Software Foundation.  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 Lesser General Public License
  along with this program; if not, see <http://www.gnu.org/licenses/>.
*/

#include "codec2.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#define NONE      0  /* no bit errors         */
#define UNIFORM   1  /* random bit errors     */
#define TWO_STATE 2  /* Two state error model */

int main(int argc, char *argv[])
{
    int            mode;
    void          *codec2;
    FILE          *fin;
    FILE          *fout;
    short         *buf;
    unsigned char *bits;
    int            nsam, nbit, nbyte, i, byte, frames, bit_errors, error_mode;
    int            state, next_state;
    float          ber, r, pstate0, pstate1;

    if (argc < 4) {
	printf("basic usage...............: c2dec 3200|2400|1400|1200 InputBitFile OutputRawSpeechFile\n");
	printf("uniform errors usage.......: c2dec 3200|2400|1400|1200 InputBitFile OutputRawSpeechFile uniformBER\n");
	printf("two state fading usage....: c2dec 3200|2400|1400|1200 InputBitFile OutputRawSpeechFile probGood probBad\n");
	printf("e.g    c2dec 1400 hts1a.c2 hts1a_1400.raw\n");
	printf("e.g    c2dec 1400 hts1a.c2 hts1a_1400.raw 0.9\n");
	printf("e.g    c2dec 1400 hts1a.c2 hts1a_1400.raw 0.99 0.9\n");
	exit(1);
    }

    if (strcmp(argv[1],"3200") == 0)
	mode = CODEC2_MODE_3200;
    else if (strcmp(argv[1],"2400") == 0)
	mode = CODEC2_MODE_2400;
    else if (strcmp(argv[1],"1400") == 0)
	mode = CODEC2_MODE_1400;
    else if (strcmp(argv[1],"1200") == 0)
	mode = CODEC2_MODE_1200;
    else {
	fprintf(stderr, "Error in mode: %s.  Must be 4800, 3200, 2400, 1400 or 1200\n", argv[1]);
	exit(1);
    }
    
    if (strcmp(argv[2], "-")  == 0) fin = stdin;
    else if ( (fin = fopen(argv[2],"rb")) == NULL ) {
	fprintf(stderr, "Error opening input bit file: %s: %s.\n",
         argv[2], strerror(errno));
	exit(1);
    }

    if (strcmp(argv[3], "-") == 0) fout = stdout;
    else if ( (fout = fopen(argv[3],"wb")) == NULL ) {
	fprintf(stderr, "Error opening output speech file: %s: %s.\n",
         argv[3], strerror(errno));
	exit(1);
    }

    error_mode = NONE;
    ber = 0.0;
    pstate0 = pstate1 = 0.0;

    if (argc == 5) {
        error_mode = UNIFORM;
	ber = atof(argv[4]);
    }

    if (argc == 6) {
        error_mode = TWO_STATE;
	pstate0 = atof(argv[4]);
	pstate1 = atof(argv[5]);
        state = 0;
    }

    codec2 = codec2_create(mode);
    nsam = codec2_samples_per_frame(codec2);
    nbit = codec2_bits_per_frame(codec2);
    buf = (short*)malloc(nsam*sizeof(short));
    nbyte = (nbit + 7) / 8;
    bits = (unsigned char*)malloc(nbyte*sizeof(char));
    frames = bit_errors = 0;

    while(fread(bits, sizeof(char), nbyte, fin) == (size_t)nbyte) {
	frames++;
	if (error_mode == UNIFORM) {
	    for(i=0; i<nbit; i++) {
		r = (float)rand()/RAND_MAX;
		if (r < ber) {
		    byte = i/8;
		    //printf("nbyte %d nbit %d i %d byte %d\n", nbyte, nbit, i, byte);
		    bits[byte] ^= 1 << (i - byte*8);
		    bit_errors++;
		}
	    }
	}

	if (error_mode == TWO_STATE) {
            next_state = state;
            switch(state) {
            case 0:

                /* clear channel state - no bit errors */

  		r = (float)rand()/RAND_MAX;
                if (r > pstate0)
                    next_state = 1;
                break;

            case 1:
                
                /* burst error state - 50% bit error rate */

                for(i=0; i<nbit; i++) {
                    r = (float)rand()/RAND_MAX;
                    if (r < 0.5) {
                        byte = i/8;
                        bits[byte] ^= 1 << (i - byte*8);
                        bit_errors++;
                    }
		}

  		r = (float)rand()/RAND_MAX;
                if (r > pstate1)
                    next_state = 0;
                break;

	    }
               
            state = next_state;
        }

	codec2_decode(codec2, buf, bits);
 	fwrite(buf, sizeof(short), nsam, fout);
	//if this is in a pipeline, we probably don't want the usual
        //buffering to occur
        if (fout == stdout) fflush(stdout);
        if (fin == stdin) fflush(stdin);         
    }

    if (ber != 0.0)
	fprintf(stderr, "actual BER: %1.3f\n", (float)bit_errors/(frames*nbit));

    codec2_destroy(codec2);

    free(buf);
    free(bits);
    fclose(fin);
    fclose(fout);

    return 0;
}