First draft of 77-bit packing

This commit is contained in:
Karlis Goba 2018-10-24 10:35:26 +03:00
parent 95153e6de0
commit 4bf6772c94

192
pack77.cpp Normal file
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#include <string.h>
#include <stdint.h>
#include "text.h"
const char *A0 = " 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ+-./?";
const char *A1 = " 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const char *A2 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const char *A3 = "0123456789";
const char *A4 = " ABCDEFGHIJKLMNOPQRSTUVWXYZ";
int index(const char *string, char c) {
for (int i = 0; *string; ++i, ++string) {
if (c == *string) {
return i;
}
}
return -1; // Not found
}
// Pack a special token, a 22-bit hash code, or a valid base call
// into a 28-bit integer.
int32_t pack28(const char *callsign) {
constexpr int32_t NTOKENS = 2063592L;
constexpr int32_t MAX22 = 4194304L;
int length = strlen(callsign); // We will need it later
if (length > 13) return -1;
// Check for special tokens first
if (equals(callsign, "DE")) return 0;
if (equals(callsign, "QRZ")) return 1;
if (equals(callsign, "CQ")) return 2;
if (starts_with(callsign, "CQ_")) {
int nnum = 0, nlet = 0;
// if(nnum.eq.3 .and. nlet.eq.0) then n28=3+nqsy
// if(nlet.ge.1 .and. nlet.le.4 .and. nnum.eq.0) then n28=3+1000+m
}
// Check for <...> callsign
// if(c13(1:1).eq.'<')then
// call save_hash_call(c13,n10,n12,n22) !Save callsign in hash table
// n28=NTOKENS + n22
char c6[6] = {' ', ' ', ' ', ' ', ' ', ' '};
// Work-around for Swaziland prefix:
if (starts_with(callsign, "3DA0") && length <= 7) {
memcpy(c6, "3D0", 3);
memcpy(c6 + 3, callsign + 4, length - 4);
}
// Work-around for Guinea prefixes:
else if (starts_with(callsign, "3X") && is_letter(callsign[2]) && length <= 7) {
memcpy(c6, "Q", 1);
memcpy(c6 + 1, callsign + 2, length - 2);
}
else {
if (is_digit(callsign[2]) && length <= 6) {
memcpy(c6, callsign, length);
}
else if (is_digit(callsign[1]) && length <= 5) {
memcpy(c6 + 1, callsign, length);
}
}
// Check for standard callsign
int i0, i1, i2, i3, i4, i5;
if ((i0 = index(A1, c6[0])) >= 0 && (i1 = index(A2, c6[1])) >= 0 &&
(i2 = index(A3, c6[2])) >= 0 && (i3 = index(A4, c6[3])) >= 0 &&
(i4 = index(A4, c6[4])) >= 0 && (i5 = index(A4, c6[5])) >= 0)
{
// This is a standard callsign
int32_t n28 = i0;
n28 = n28 * 36 + i1;
n28 = n28 * 10 + i2;
n28 = n28 * 27 + i3;
n28 = n28 * 27 + i4;
n28 = n28 * 27 + i5;
return NTOKENS + MAX22 + n28;
}
//char c13[13];
// Treat this as a nonstandard callsign: compute its 22-bit hash
// call save_hash_call(c13,n10,n12,n22) !Save callsign in hash table
// n28=NTOKENS + n22
// n28=iand(n28,ishft(1,28)-1)
return -1;
}
// Check if a string could be a valid standard callsign or a valid
// compound callsign.
// Return base call "bc" and a logical "cok" indicator.
bool chkcall(const char *call, char *bc) {
int length = strlen(call); // n1=len_trim(w)
if (length > 11) return false;
if (0 != strchr(call, '.')) return false;
if (0 != strchr(call, '+')) return false;
if (0 != strchr(call, '-')) return false;
if (0 != strchr(call, '?')) return false;
if (length > 6 && 0 != strchr(call, '/')) return false;
//bc=w(1:6)
//i0=index(w,'/')
//if(max(i0-1,n1-i0).gt.6) go to 100 !Base call must be < 7 characters
//if(i0.ge.2 .and. i0.le.n1-1) then !Extract base call from compound call
// if(i0-1.le.n1-i0) bc=w(i0+1:n1)//' '
// if(i0-1.gt.n1-i0) bc=w(1:i0-1)//' '
}
// Pack Type 1 (Standard 77-bit message) and Type 2 (ditto, with a "/P" call)
void pack77_1(const char *msg, uint8_t i3, uint8_t *b77) {
// if(index(w(1),'/P').ge.4 .or. index(w(1),'/R').ge.4) ipa=1
// if(index(w(2),'/P').ge.4 .or. index(w(2),'/R').ge.4) ipb=1
uint32_t n28a, n28b;
uint16_t igrid4;
n28a <<= 1; // ipa = 0
n28b <<= 1; // ipb = 0
//igrid4 |= 0x8000; // ir = 1
// write(c77,1000) n28a,ipa,n28b,ipb,ir,igrid4,i3
// 1000 format(2(b28.28,b1),b1,b15.15,b3.3)
// (28 + 1) + (28 + 1) + (1 + 15) + 3
b77[0] = (n28a >> 21);
b77[1] = (n28a >> 13);
b77[2] = (n28a >> 5);
b77[3] = (uint8_t)(n28a << 3) | (uint8_t)(n28b >> 26);
b77[4] = (n28b >> 18);
b77[5] = (n28a >> 10);
b77[6] = (n28a >> 2);
b77[7] = (uint8_t)(n28a << 6) | (uint8_t)(igrid4 >> 10);
b77[8] = (igrid4 >> 2);
b77[9] = (uint8_t)(igrid4 << 6) | (uint8_t)(i3 << 3);
}
void packtext77(const char *c13, uint8_t *b71) {
// TODO: w=adjustr(c13)
for (int i = 0; i < 9; ++i) {
b71[i] = 0;
}
for (int j = 0; j < 13; ++j) {
int q = index(A0, c13[j]);
// Multiply b71 by 42
uint16_t x = 0;
for (int i = 8; i >= 0; --i) {
x += b71[i] * (uint16_t)42;
b71[i] = x;
x >>= 8;
}
// Add index of the current char
x = (q > 0) ? q : 0;
for (int i = 8; i >= 0; --i) {
if (x == 0) break;
x += b71[i];
b71[i] = x;
x >>= 8;
}
}
}
int pack77(const char *msg, uint8_t *c77) {
// Check Type 1 (Standard 77-bit message) or Type 2, with optional "/P"
if (starts_with(msg, "CQ ")) {
pack77_1(nwords,w,i3,n3,c77);
return;
}
// Check 0.5 (telemetry)
// i3=0 n3=5 write(c77,1006) ntel,n3,i3 1006 format(b23.23,2b24.24,2b3.3)
// Check Type 4 (One nonstandard call and one hashed call)
// pack77_4(nwords,w,i3,n3,c77)
// Default to free text
// i3=0 n3=0
// packtext77(msg(1:13),c77(1:71))
// write(c77(72:77),'(2b3.3)') n3,i3
}