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/* CWirc - X-Chat plugin for sending and receiving raw morse code over IRC
(c) Pierre-Philippe Coupard - 18/06/2003
Morse decoder
This program is distributed under the terms of the GNU General Public License
See the COPYING file for details
*/
#include <stdio.h>
#include <string.h>
#include "types.h"
#include "cwdecoder.h"
#include "morsecodes.h"
#include "cwirc.h"
/* Definitions */
#define CW_BUF_MAX_SIZE CW_SEQUENCE_MAX+2 /* Max. dits or dahs we buffer*/
#define DECODER_INERTIA 4 /* How slowly the decoder adapts
to a new keying speed */
/* Global variables */
struct cwcodeset cwirc_cw_table[NB_CW_CODE_SETS]=MORSE_CODES;
/* Prototypes */
static void decode_morse_code(T_BOOL key,double ticklen,int cwcodeset,
T_BOOL reset_decoder);
static void decode_dot_code(T_BOOL key,double ticklen,int cwcodeset,
T_BOOL reset_decoder);
static char *decode_cw_sequence(int cwcodeset,char *cwbuf,char *decoded_char);
static void insert_character_in_decoder_buffer(char *c,T_BOOL delete_spaces);
/* Functions */
void cwirc_decode_cw(T_BOOL key,double ticklen,int cwcodeset)
{
/* Is the decoder disabled ? */
if(cwirc_cw_table[sharedmem->cwcodeset].cwcodetype==NOCODE)
if(sharedmem->decoded_msg_wpm!=WPM_DECODER_DISABLED)
sharedmem->reset_decoder=1;
else
return;
else
if(sharedmem->decoded_msg_wpm==WPM_DECODER_DISABLED)
sharedmem->decoded_msg_wpm=WPM_UNKNOWN_WPM;
/* Have we been asked to reset the decoder ? */
if(sharedmem->reset_decoder)
{
decode_morse_code(key,ticklen,cwcodeset,1);
decode_dot_code(key,ticklen,cwcodeset,1);
sharedmem->decoded_msg_buf[0]=0;
sharedmem->decoded_msg_buf_char_markers[0]=0;
sharedmem->decoded_msg_wpm=cwirc_cw_table[sharedmem->cwcodeset].cwcodetype
==NOCODE?WPM_DECODER_DISABLED:WPM_UNKNOWN_WPM;
sharedmem->decoded_msg_updated=1;
sharedmem->reset_decoder=0;
}
/* Is the chosen code set in Morse code ? */
if(cwirc_cw_table[cwcodeset].cwcodetype==MORSE)
{
decode_morse_code(key,ticklen,cwcodeset,0);
return;
}
/* Is the chosen code set in DOT code ? */
if(cwirc_cw_table[cwcodeset].cwcodetype==DOT)
{
decode_dot_code(key,ticklen,cwcodeset,0);
return;
}
}
/* Decode international Morse code */
void decode_morse_code(T_BOOL key,double ticklen,int cwcodeset,
T_BOOL reset_decoder)
{
static double evtlen=0;
static double beeplenprev=0,lastshortbeeplen=0,lastlongbeeplen=0;
static double lastbeep_too_short_by=0; /* in ms */
static double ditlen=0;
static T_BOOL keyprev=0;
static char cwbuf[CW_BUF_MAX_SIZE]="";
static T_BOOL wait_for_end_of_word=0;
static char newbeep=0;
char decoded_char[CW_SYMBOL_MAX+1]="";
int i;
/* Should we reset the decoder's internal states? */
if(reset_decoder)
{
evtlen=0;
beeplenprev=0;
lastshortbeeplen=0;
lastlongbeeplen=0;
lastbeep_too_short_by=0;
ditlen=0;
keyprev=0;
cwbuf[0]=0;
wait_for_end_of_word=0;
newbeep=0;
decoded_char[0]=0;
return;
}
/* Did the key change state ? */
if(key!=keyprev)
{
wait_for_end_of_word=0;
if(!key) /* Was the key released ? */
{
if(evtlen<beeplenprev/2)
newbeep='.';
else if(evtlen>beeplenprev*2)
newbeep='-';
if((i=strlen(cwbuf))<CW_BUF_MAX_SIZE-1)
{
cwbuf[i]=newbeep;
cwbuf[i+1]=0;
}
if(newbeep=='.')
lastshortbeeplen=evtlen;
else
lastlongbeeplen=evtlen;
/* Progressively deviate the "official" dit length toward the last short
beep length, so the decoder isn't thrown off track immediately when the
operator made a temporary timing mistake */
if(lastlongbeeplen!=0 && lastshortbeeplen!=0)
ditlen=(ditlen*(DECODER_INERTIA-1)+
((3*lastshortbeeplen+lastlongbeeplen)/6))/DECODER_INERTIA;
else
if(lastshortbeeplen!=0)
ditlen=(ditlen*(DECODER_INERTIA-1)+lastshortbeeplen)/DECODER_INERTIA;
else
ditlen=(ditlen*(DECODER_INERTIA-1)+lastlongbeeplen/3)/DECODER_INERTIA;
if(newbeep=='.')
lastbeep_too_short_by=ditlen>evtlen?ditlen-evtlen:0;
else
lastbeep_too_short_by=ditlen*3>evtlen?ditlen*3-evtlen:0;
beeplenprev=evtlen;
}
evtlen=0;
}
/* If the key has been released for over a dit length * 2, decode the
character. Allow for timing imprecision if the last beep was too short */
if(!key && !keyprev && (evtlen-lastbeep_too_short_by)>ditlen*2 && cwbuf[0])
{
/* Decode the cw character */
decode_cw_sequence(cwcodeset,cwbuf,decoded_char);
/* Empty the buffer */
cwbuf[0]=0;
wait_for_end_of_word=1;
}
/* If the key has been released for over a dit length * 4, send a space.
Allow for timing imprecision if the last beep was too short */
if((evtlen-lastbeep_too_short_by)>ditlen*4 && wait_for_end_of_word)
{
strcpy(decoded_char," ");
wait_for_end_of_word=0;
}
/* Is there a new decoded character ? */
if(decoded_char[0])
{
/* Add the character in the buffer, or remove the last character */
insert_character_in_decoder_buffer(decoded_char,1);
decoded_char[0]=0;
/* Report the current decoder's speed */
if(ditlen>0)
sharedmem->decoded_msg_wpm=1200/ditlen;
else
sharedmem->decoded_msg_wpm=WPM_UNKNOWN_WPM;
/* Assert this for the display routine */
sharedmem->decoded_msg_updated=1;
}
keyprev=key;
evtlen+=ticklen;
}
/* Decode DOT code */
void decode_dot_code(T_BOOL key,double ticklen,int cwcodeset,
T_BOOL reset_decoder)
{
static double evtlen=0;
static double ditlen=0;
static T_BOOL keyprev=0;
static int dotcount=0;
static char cwbuf[CW_BUF_MAX_SIZE]="";
char decoded_char[CW_SYMBOL_MAX+1]="";
int i;
/* Should we reset the decoder's internal states? */
if(reset_decoder)
{
evtlen=0;
ditlen=0;
keyprev=0;
dotcount=0;
cwbuf[0]=0;
decoded_char[0]=0;
return;
}
/* Did the key change state ? */
if(key!=keyprev)
{
if(!key) /* Was the key released ? */
{
if(dotcount<9)
dotcount++; /* Count dots in the current character element */
/* Progressively deviate the "official" dit length toward the last short
beep length, so the decoder isn't thrown off track immediately when the
operator made a temporary timing mistake */
ditlen=(ditlen*(DECODER_INERTIA-1)+evtlen)/DECODER_INERTIA;
}
evtlen=0;
}
/* If the key has been released for over a dit length * 2 and there were dots
counted, add the current character element to the buffer. */
if(!key && !keyprev && evtlen>ditlen*2 && dotcount &&
(i=strlen(cwbuf))<CW_BUF_MAX_SIZE-1)
{
cwbuf[i]='0'+dotcount;
cwbuf[i+1]=0;
dotcount=0;
}
/* If the key has been released for over a dit length * 5 and there are
character elements to decode, decode the character */
if(evtlen>ditlen*5 && cwbuf[0])
{
/* Decode the cw character */
decode_cw_sequence(cwcodeset,cwbuf,decoded_char);
/* Empty the buffer */
cwbuf[0]=0;
}
/* Is there a new decoded character ? */
if(decoded_char[0])
{
/* Add the character in the buffer, or remove the last character */
insert_character_in_decoder_buffer(decoded_char,0);
decoded_char[0]=0;
/* Report the current decoder's speed */
if(ditlen>0)
sharedmem->decoded_msg_wpm=600/ditlen; /* Calculated on the basis of
100 dits per PARIS word in
DOT code */
else
sharedmem->decoded_msg_wpm=WPM_UNKNOWN_WPM;
/* Assert this for the display routine */
sharedmem->decoded_msg_updated=1;
}
keyprev=key;
evtlen+=ticklen;
}
/* Find a CW sequence in the right table and return it */
static char *decode_cw_sequence(int cwcodeset,char *cwbuf,char *decoded_char)
{
int i;
/* Look for a matching sequence */
for(i=0;cwirc_cw_table[cwcodeset].cwcode[i].sequence[0] &&
strcmp(cwbuf,cwirc_cw_table[cwcodeset].cwcode[i].sequence);i++);
/* Did we find a sequence ? */
if(cwirc_cw_table[cwcodeset].cwcode[i].sequence[0])
strcpy(decoded_char,cwirc_cw_table[cwcodeset].cwcode[i].symbol);
else
{
/* Is it a continuous stream of dits ? */
if(strchr(cwbuf,'-')==NULL)
strcpy(decoded_char,"\b"); /* It's an "error" morse code */
else
strcpy(decoded_char,UNKNOWN_CHARACTER_SIGN);/* We don't know what it is */
}
return(decoded_char);
}
/* Insert a decoded character in the decoder buffer, or remove the last one
if the character is a backspace */
static void insert_character_in_decoder_buffer(char *c,T_BOOL delete_spaces)
{
int i,j,k;
k=strlen(sharedmem->decoded_msg_buf);
/* Is the character a BACKSPACE ? */
if(c[0]=='\b')
{
if(delete_spaces)
{
/* Zap the last spaces in the decoded message line */
while(k && sharedmem->decoded_msg_buf[k-1]==' ')
{
sharedmem->decoded_msg_buf[--k]=0;
sharedmem->decoded_msg_buf_char_markers[k]=0;
}
}
/* Zap the last character in the decoded message line */
while(k && sharedmem->decoded_msg_buf_char_markers[k-1]==' ')
{
sharedmem->decoded_msg_buf[--k]=0;
sharedmem->decoded_msg_buf_char_markers[k]=0;
}
if(k)
{
sharedmem->decoded_msg_buf[--k]=0;
sharedmem->decoded_msg_buf_char_markers[k]=0;
}
}
else
{
/* Do we need to make room in the decoded message buffer for the new
character ? */
j=strlen(c);
if(j+k>=DECODED_MSG_SIZE)
{
/* Find out the position of the character that'll become the new
leading character of the decoded message buffer */
for(i=j+k+1-DECODED_MSG_SIZE;
sharedmem->decoded_msg_buf_char_markers[i]==' ';i++);
/* Shift the decoded message left accordingly */
for(k=i;sharedmem->decoded_msg_buf[k];k++)
{
sharedmem->decoded_msg_buf[k-i]=sharedmem->decoded_msg_buf[k];
sharedmem->decoded_msg_buf_char_markers[k-i]=
sharedmem->decoded_msg_buf_char_markers[k];
}
sharedmem->decoded_msg_buf[k-i]=0;
sharedmem->decoded_msg_buf_char_markers[k-i]=0;
}
/* Append the new character in the buffer */
strcat(sharedmem->decoded_msg_buf,c);
/* Append the new character's start marker in the markers buffer */
for(i=0;i<j;i++)
strcat(sharedmem->decoded_msg_buf_char_markers,i?" ":"|");
}
}
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