ft8_lib/unpack.cpp
2018-10-26 15:48:27 +03:00

192 lines
4.2 KiB
C++

#include "unpack.h"
#include "text.h"
#include <string.h>
constexpr uint32_t NBASE = 37L*36L*10L*27L*27L*27L;
// convert packed character to ASCII character
// 0..9 a..z space +-./?
char charn(uint8_t c) {
if (c >= 0 && c <= 9)
return '0' + c;
if (c >= 10 && c < 36)
return 'A' + c - 10;
if (c < 42)
return " +-./?" [c - 36];
return ' ';
}
// nc is a 28-bit integer, e.g. nc1 or nc2, containing all the
// call sign bits from a packed message.
void unpackcall(uint32_t nc, char *callsign) {
callsign[5] = charn((nc % 27) + 10); // + 10 b/c only alpha+space
nc /= 27;
callsign[4] = charn((nc % 27) + 10);
nc /= 27;
callsign[3] = charn((nc % 27) + 10);
nc /= 27;
callsign[2] = charn(nc % 10); // digit only
nc /= 10;
callsign[1] = charn(nc % 36); // letter or digit
nc /= 36;
callsign[0] = charn(nc);
callsign[6] = 0;
}
// extract maidenhead locator
void unpackgrid(uint32_t ng, char *grid) {
// start of special grid locators for sig strength &c.
NGBASE = 180*180
if ng == NGBASE+1:
return " "
if ng >= NGBASE+1 and ng < NGBASE+31:
return " -%02d" % (ng - (NGBASE+1)) // sig str, -01 to -30 DB
if ng >= NGBASE+31 and ng < NGBASE+62:
return "R-%02d" % (ng - (NGBASE+31))
if ng == NGBASE+62:
return "RO "
if ng == NGBASE+63:
return "RRR "
if ng == NGBASE+64:
return "73 "
lat = (ng % 180) - 90
ng = int(ng / 180)
lng = (ng * 2) - 180
g = "%c%c%c%c" % (ord('A') + int((179-lng)/20),
ord('A') + int((lat+90)/10),
ord('0') + int(((179-lng)%20)/2),
ord('0') + (lat+90)%10)
if g[0:2] == "KA":
// really + signal strength
sig = int(g[2:4]) - 50
return "+%02d" % (sig)
if g[0:2] == "LA":
// really R+ signal strength
sig = int(g[2:4]) - 50
return "R+%02d" % (sig)
}
void unpacktext(uint32_t nc1, uint32_t nc2, uint16_t ng, char *text) {
uint32_t nc3 = ng & 0x7FFF;
if (nc1 & 1 != 0)
nc3 |= 0x08000;
nc1 >>= 1;
if (nc2 & 1 != 0)
nc3 |= 0x10000;
nc2 >>= 1;
for (int i = 4; i >= 0; --i) {
text[i] = charn(nc1 % 42);
nc1 /= 42;
}
for (int i = 9; i >= 5; --i) {
text[i] = charn(nc2 % 42);
nc2 /= 42;
}
for (int i = 12; i >= 10; --i) {
text[i] = charn(nc3 % 42);
nc3 /= 42;
}
text[13] = 0;
}
int unpack(const uint8_t *a72, char *message) {
uint32_t nc1, nc2;
uint16_t ng;
nc1 = (a72[0] << 20);
nc1 |= (a72[1] << 12);
nc1 |= (a72[2] << 4);
nc1 |= (a72[3] >> 4);
nc2 = (a72[3] << 24);
nc2 |= (a72[4] << 16);
nc2 |= (a72[5] << 8);
nc2 |= (a72[6]);
ng = (a72[7] >> 8);
ng |= (a72[8]);
if (ng & 0x8000) {
unpacktext(nc1, nc2, ng, message);
return 0;
}
char c2[7];
char grid[5];
if (nc1 == NBASE+1) {
// CQ with standard callsign
unpackcall(nc2, c2);
unpackgrid(ng, grid);
strcpy(message, "CQ ");
strcat(message, c2);
strcat(message, " ");
strcat(message, grid);
return 0;
}
if (nc1 >= 267649090L && nc1 <= 267698374L) {
// CQ with suffix (e.g. /QRP)
uint32_t n = nc1 - 267649090L;
char sf[4];
sf[0] = charn(n % 37);
n /= 37;
sf[1] = charn(n % 37);
n /= 37;
sf[2] = charn(n % 37);
unpackcall(nc2, c2);
unpackgrid(ng, grid);
strcpy(message, "CQ ");
strcat(message, c2);
strcat(message, "/");
strcat(message, sf);
strcat(message, " ");
strcat(message, grid);
return 0;
}
char c1[7];
unpackcall(nc1, c1);
if (equals(c1, "CQ9DX ")) {
strcpy(c1, "CQ DX");
}
else if (starts_with(c1, " E9") && is_letter(c1[3]) && is_letter(c1[4]) && is_space(c1[5])) {
strcpy(c1, "CQ ");
c1[5] = 0;
}
unpackcall(nc2, c2);
unpackgrid(ng, grid);
strcpy(message, c1);
strcat(message, " ");
strcat(message, c2);
strcat(message, " ");
strcat(message, grid);
//if "000AAA" in msg:
// return None
return 0;
}