kopia lustrzana https://github.com/M17-Project/M17_Implementations
114 wiersze
2.2 KiB
C
114 wiersze
2.2 KiB
C
//--------------------------------------------------------------------
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// M17 C library - m17call.c
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//
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// This file contains:
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// - callsign encoder and decoders
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//
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// Wojciech Kaczmarski, SP5WWP
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// M17 Project, 29 December 2023
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//--------------------------------------------------------------------
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#include <stdio.h>
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#include <string.h>
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#include "m17call.h"
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//decodes a 6-byte long array to a callsign
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void decode_callsign_bytes(uint8_t *outp, const uint8_t *inp)
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{
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uint64_t encoded=0;
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//repack the data to a uint64_t
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for(uint8_t i=0; i<6; i++)
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encoded|=(uint64_t)inp[5-i]<<(8*i);
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//check if the value is reserved (not a callsign)
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if(encoded>=262144000000000ULL)
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{
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if(encoded==0xFFFFFFFFFFFF) //broadcast
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{
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sprintf((char*)outp, "#BCAST");
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}
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else
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{
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outp[0]=0;
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}
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return;
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}
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//decode the callsign
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uint8_t i=0;
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while(encoded>0)
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{
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outp[i]=" ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-/."[encoded%40];
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encoded/=40;
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i++;
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}
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outp[i]=0;
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}
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//decodes a 48-bit value to a callsign
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void decode_callsign_value(uint8_t *outp, const uint64_t inp)
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{
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uint64_t encoded=inp;
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//check if the value is reserved (not a callsign)
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if(encoded>=262144000000000ULL)
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{
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if(encoded==0xFFFFFFFFFFFF) //broadcast
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{
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sprintf((char*)outp, "#BCAST");
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}
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else
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{
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outp[0]=0;
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}
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return;
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}
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//decode the callsign
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uint8_t i=0;
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while(encoded>0)
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{
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outp[i]=" ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-/."[encoded%40];
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encoded/=40;
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i++;
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}
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outp[i]=0;
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}
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//encode callsign into a 48-bit value
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uint8_t encode_callsign(uint64_t* out, const uint8_t* inp)
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{
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//assert inp length
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if(strlen((const char*)inp)>9)
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{
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return -1;
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}
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const uint8_t charMap[40]=" ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-/.";
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uint64_t tmp=0;
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if(strcmp((const char*)inp, "ALL")==0)
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{
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*out=0xFFFFFFFFFFFF;
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return 0;
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}
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for(int8_t i=strlen((const char*)inp)-1; i>=0; i--)
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{
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for(uint8_t j=0; j<40; j++)
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{
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if(inp[i]==charMap[j])
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{
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tmp=tmp*40+j;
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break;
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}
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}
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}
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*out=tmp;
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return 0;
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}
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