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kgoba-ft8_lib/ft8/v1/pack.cpp

368 wiersze
11 KiB
C++
Czysty Wina Historia

#include <string.h>
#include <cstdio>
#include "pack.h"
#include "../text.h"
constexpr int32_t NBASE = 37*36*10*27*27*27L;
constexpr int32_t NGBASE = 180*180L;
// Returns integer encoding of a character (number/digit/space).
// Alphabet: "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ +-./?"
// - Digits are encoded as 0..9
// - Letters a..z are encoded as 10..35 (case insensitive)
// - Space is encoded as 36
uint8_t nchar(char c) {
if (is_digit(c))
return (c - '0');
if (is_letter(c))
return (to_upper(c) - 'A') + 10;
switch (c) {
case ' ': return 36;
case '+': return 37;
case '-': return 38;
case '.': return 39;
case '/': return 40;
case '?': return 41;
default: return 36; // Equal to ' '
}
}
// Pack FT8 source/destination and grid data into 72 bits (stored as 9 bytes)
// [IN] nc1 - first callsign data (28 bits)
// [IN] nc2 - second callsign data (28 bits)
// [IN] ng - grid data (16 bits)
// [OUT] payload - 9 byte array to store the 72 bit payload (MSB first)
void pack3_8bit(uint32_t nc1, uint32_t nc2, uint16_t ng, uint8_t *payload) {
payload[0] = (uint8_t)(nc1 >> 20);
payload[1] = (uint8_t)(nc1 >> 12);
payload[2] = (uint8_t)(nc1 >> 4);
payload[3] = (uint8_t)(nc1 << 4) | (uint8_t)(nc2 >> 24);
payload[4] = (uint8_t)(nc2 >> 16);
payload[5] = (uint8_t)(nc2 >> 8);
payload[6] = (uint8_t)(nc2);
payload[7] = (uint8_t)(ng >> 8);
payload[8] = (uint8_t)(ng);
}
// Pack FT8 source/destination and grid data into 72 bits (stored as 12 bytes of 6-bit values)
// (Unused here, included for compatibility with WSJT-X and testing)
// [IN] nc1 - first callsign data (28 bits)
// [IN] nc2 - second callsign data (28 bits)
// [IN] ng - grid data (16 bits)
// [OUT] payload - 12 byte array to store the 72 bit payload (MSB first)
void pack3_6bit(uint32_t nc1, uint32_t nc2, uint16_t ng, uint8_t *payload) {
payload[0] = (nc1 >> 22) & 0x3f; // 6 bits
payload[1] = (nc1 >> 16) & 0x3f; // 6 bits
payload[2] = (nc1 >> 10) & 0x3f; // 6 bits
payload[3] = (nc1 >> 4) & 0x3f; // 6 bits
payload[4] = ((nc1 & 0xf) << 2) | ((nc2 >> 26) & 0x3); // 4+2 bits
payload[5] = (nc2 >> 20) & 0x3f; // 6 bits
payload[6] = (nc2 >> 14) & 0x3f; // 6 bits
payload[7] = (nc2 >> 8) & 0x3f; // 6 bits
payload[8] = (nc2 >> 2) & 0x3f; // 6 bits
payload[9] = ((nc2 & 0x3) << 4) | ((ng >> 12) & 0xf); // 2+4 bits
payload[10] = (ng >> 6) & 0x3f; // 6 bits
payload[11] = (ng >> 0) & 0x3f; // 6 bits
}
// Pack a valid callsign into a 28-bit integer.
// Note that callsign points to a portion of text and may not be zero-terminated.
int32_t packcall(const char *callsign, int length) {
if (length > 6) {
return -1;
}
if (starts_with(callsign, "CQ ")) {
// TODO: support 'CQ nnn' frequency specification
//if (callsign(4:4).ge.'0' .and. callsign(4:4).le.'9' .and. &
// callsign(5:5).ge.'0' .and. callsign(5:5).le.'9' .and. &
// callsign(6:6).ge.'0' .and. callsign(6:6).le.'9') then
// read(callsign(4:6),*) nfreq
// ncall=NBASE + 3 + nfreq
//endif
return NBASE + 1;
}
if (starts_with(callsign, "QRZ ")) {
return NBASE + 2;
}
if (starts_with(callsign, "DE ")) {
return 267796945;
}
char callsign2[7] = {' ', ' ', ' ', ' ', ' ', ' ', 0}; // 6 spaces with zero terminator
// Work-around for Swaziland prefix (see WSJT-X code):
if (starts_with(callsign, "3DA0")) {
// callsign='3D0'//callsign(5:6)
memcpy(callsign2, "3D0", 3);
if (length > 4) {
memcpy(callsign2 + 3, callsign + 4, length - 4);
}
}
// Work-around for Guinea prefixes (see WSJT-X code):
else if (starts_with(callsign, "3X") && is_letter(callsign[2])) {
//callsign='Q'//callsign(3:6)
memcpy(callsign2, "Q", 1);
if (length > 2) {
memcpy(callsign2 + 1, callsign + 2, length - 2);
}
}
else {
// Just copy, no modifications needed
// Check for callsigns with 1 symbol prefix
if (!is_digit(callsign[2]) && is_digit(callsign[1])) {
if (length > 5) {
return -1;
}
// Leave one space at the beginning as padding
memcpy(callsign2 + 1, callsign, length);
}
else {
memcpy(callsign2, callsign, length);
}
}
// Check if the callsign consists of valid characters
if (!is_digit(callsign2[0]) && !is_letter(callsign2[0]) && !is_space(callsign2[0]))
return -3;
if (!is_digit(callsign2[1]) && !is_letter(callsign2[1]))
return -3;
if (!is_digit(callsign2[2]))
return -3;
if (!is_letter(callsign2[3]) && !is_space(callsign2[3]))
return -3;
if (!is_letter(callsign2[4]) && !is_space(callsign2[4]))
return -3;
if (!is_letter(callsign2[5]) && !is_space(callsign2[5]))
return -3;
// Form a 28 bit integer from callsign parts
int32_t ncall = nchar(callsign2[0]);
ncall = 36*ncall + nchar(callsign2[1]);
ncall = 10*ncall + nchar(callsign2[2]);
ncall = 27*ncall + nchar(callsign2[3]) - 10;
ncall = 27*ncall + nchar(callsign2[4]) - 10;
ncall = 27*ncall + nchar(callsign2[5]) - 10;
return ncall;
}
// Pack a valid grid locator into an integer.
int16_t packgrid(const char *grid) {
printf("Grid = [%s]\n", grid);
int len = strlen(grid);
if (len == 0) {
// Blank grid is OK
return NGBASE + 1;
}
// Check for RO, RRR, or 73 in the message field normally used for grid
if (equals(grid, "RO")) {
return NGBASE + 62;
}
if (equals(grid, "RRR")) {
return NGBASE + 63;
}
if (equals(grid, "73")) {
return NGBASE + 64;
}
// Attempt to parse signal reports (e.g. "-07", "R+20")
char c1 = grid[0];
int n;
if (c1 == 'R') {
n = dd_to_int(grid + 1, 3); // read(grid(2:4),*,err=30,end=30) n
}
else {
n = dd_to_int(grid, 3); // read(grid,*,err=20,end=20) n
}
// First, handle signal reports in the original range, -01 to -30 dB
if (n >= -30 && n <= -1) {
if (c1 == 'R') {
return NGBASE + 31 + (-n);
}
else {
return NGBASE + 1 + (-n);
}
}
char grid4[4];
memcpy(grid4, grid, 4);
// TODO: Check for extended-range signal reports: -50 to -31, and 0 to +49
// if (n >= -50 && n <= 49) {
// if (c1 == 'R') {
// // write(grid,1002) n+50 1002 format('LA',i2.2)
// }
// else {
// // write(grid,1003) n+50 1003 format('KA',i2.2)
// }
// // go to 40
// }
// else {
// // error
// return -1;
// }
// Check if the grid locator is properly formatted
if (len != 4) return -1;
if (grid4[0] < 'A' || grid4[0] > 'R') return -1;
if (grid4[1] < 'A' || grid4[1] > 'R') return -1;
if (grid4[2] < '0' || grid4[2] > '9') return -1;
if (grid4[3] < '0' || grid4[3] > '9') return -1;
// Extract latitude and longitude
int lng = (grid4[0] - 'A') * 20;
lng += (grid4[2] - '0') * 2;
lng = 179 - lng;
int lat = (grid4[1] - 'A') * 10;
lat += (grid4[3] - '0') * 1;
lat -= 90;
// Convert latitude and longitude into single number
int16_t ng = (lng + 180) / 2;
ng *= 180;
ng += lat + 90;
return ng;
}
// Pack a free-text message into 3 integers (28+28+15 bits)
// NOTE: msg MUST contain at least 13 characters!
// No checking is done. Exactly 13 characters will be processed.
void packtext(const char *msg, int32_t &nc1, int32_t &nc2, int16_t &ng) {
int32_t nc3;
nc1 = nc2 = nc3 = 0;
// Pack 5 characters (42^5) into 27 bits
for (int i = 0; i < 5; ++i) { // First 5 characters in nc1
uint8_t j = nchar(msg[i]); // Get character code
nc1 = 42*nc1 + j;
}
// Pack 5 characters (42^5) into 27 bits
for (int i = 5; i < 10; ++i) { // Characters 6-10 in nc2
uint8_t j = nchar(msg[i]); // Get character code
nc2 = 42*nc2 + j;
}
// Pack 3 characters (42^3) into 17 bits
for (int i = 10; i < 13; ++i) { // Characters 11-13 in nc3
uint8_t j = nchar(msg[i]); // Get character code
nc3 = 42*nc3 + j;
}
// We now have used 17 bits in nc3. Must move one each to nc1 and nc2.
nc1 <<= 1;
if (nc3 & 0x08000) nc1 |= 1;
nc2 <<= 1;
if (nc3 & 0x10000) nc2 |= 1;
ng = nc3 & 0x7FFF;
}
int packmsg(const char *msg, uint8_t *dat) { // , itype, bcontest
// TODO: check what is maximum allowed length?
if (strlen(msg) > 22) {
return -1;
}
char msg2[23]; // Including zero terminator!
fmtmsg(msg2, msg);
//LOG("msg2 = [%s]\n", msg2);
// TODO: Change 'CQ n ' type messages to 'CQ 00n '
//if(msg(1:3).eq.'CQ ' .and. msg(4:4).ge.'0' .and. msg(4:4).le.'9' &
// .and. msg(5:5).eq.' ') msg='CQ 00'//msg(4:)
if (starts_with(msg2, "CQ ")) {
if (msg2[3] == 'D' && msg2[4] == 'X' && is_space(msg2[5])) {
// Change 'CQ DX ' to 'CQ9DX '
msg2[2] = '9';
}
else if (is_letter(msg2[3]) && is_letter(msg2[4]) && is_space(msg2[5])) {
// Change 'CQ xy ' type messages to 'E9xy '
msg2[0] = 'E';
msg2[1] = '9';
// Delete the extra space
char *ptr = msg2 + 2;
while (*ptr) {
ptr[0] = ptr[1];
++ptr;
}
}
}
int msg2len = strlen(msg2);
int32_t nc1 = -1;
int32_t nc2 = -1;
int16_t ng = -1;
// Try to split the message into three space-delimited fields
// by locating spaces and changing them to zero terminators
// Locate the first delimiter in the message
const char *s1 = strchr(msg2, ' ');
if (s1 != 0) {
int s1len = s1 - msg2;
int s2len;
++s1; // s1 now points to the second field
// Locate the second delimiter in the message
const char *s2 = strchr(s1 + 1, ' ');
if (s2 == 0) {
// If the second space is not found, point to the end of string
// to allow for blank grid (third field)
s2 = msg2 + msg2len;
s2len = s2 - s1;
}
else {
s2len = s2 - s1;
++s2; // s2 now points to the third field
}
// TODO: process callsign prefixes/suffixes
// Pack message fields into integers
nc1 = packcall(msg2, s1len);
nc2 = packcall(s1, s2len);
ng = packgrid(s2);
}
// Check for success in all three fields
if (nc1 < 0 || nc2 < 0 || ng < 0) {
// Treat as plain text message
// Pad with spaces at the end if necessary
for (int i = msg2len; i < 13; ++i) {
msg2[i] = ' ';
}
msg2[13] = 0;
printf("Treating as free text\n");
packtext(msg2, nc1, nc2, ng);
ng += 0x8000; // Set bit 15 (we abuse signed int here)
}
//LOG("nc1 = %d [%04X], nc2 = %d [%04X], ng = %d\n", nc1, nc1, nc2, nc2, ng);
// Originally the data was packed in bytes of 6 bits.
// This seems to waste memory unnecessary and complicate the code, so we pack it in 8 bit values.
pack3_8bit((uint32_t)nc1, (uint32_t)nc2, (uint16_t)ng, dat);
//pack3_6bit(nc1, nc2, ng, dat);
return 0; // Success!
}
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