tty_enc.c

完整的EVRC压缩解压缩算法源码,通过C-C++编译后可以运行!

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#include <stdio.h>
#include "typedef.h"
/*#include "const.h"*/
#include "tty.h"


Word16   ditbuf[DITBUF_LEN];


/***********************************************************************
*   init_tty_enc()
************************************************************************/
void init_tty_enc(
    Word16   *tty_char,
    Word16   *counter,
    Word16   *tty_baud_rate)
{
    Word16 i;

    init_get_tty_bit();
    init_dit_to_ascii();

    *tty_char = NON_TTY;
    *counter = NON_TTY;
    *tty_baud_rate = DEFAULT_TTY_BAUD_RATE;

    for( i=0 ; i < DITBUF_LEN ; i++ )
    {
        ditbuf[i] = ERASE;
    }
}



/***********************************************************************
*   tty_enc()
************************************************************************/
Word16 tty_enc(
    Word16   *tty_char,      /* (o): tty character                       */
    Word16   *counter,       /* (o): tty character counter               */
    Word16   *tty_baud_rate, /* (i/o): tty baud rate                     */
    Word16   pcm_buf[],      /* (i): input pcm                           */
    Word16   len             /* (i): length of pcm buffer (FRAMESIZE)    */
)
{
    Word16  i;

    tty_header_in( counter );

    /* Save history dits */
    for( i=0 ; i < DITBUF_LEN-DITS_PER_FRAME ; i++ )
    {
        ditbuf[i] = ditbuf[DITS_PER_FRAME+i];       
    }

    baudot_to_dit( ditbuf+DITBUF_LEN-DITS_PER_FRAME,
                   pcm_buf );


    dit_to_ascii( tty_char, counter, tty_baud_rate, ditbuf);

                
    if( *counter == NON_TTY )
    {

        return(0);
    }

    i = *counter;
    tty_header_out( counter );


    return(i);

}