/*************************************************************************** * Copyright (C) 2025 by Federico Amedeo Izzo IU2NUO, * * Niccolò Izzo IU2KIN * * Frederik Saraci IU2NRO * * Silvano Seva IU2KWO * * * * This program is free software; you can redistribute it and/or modify * * it under the terms of the GNU General Public License as published by * * the Free Software Foundation; either version 3 of the License, or * * (at your option) any later version. * * * * This program is distributed in the hope that it will be useful, * * but WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * * GNU General Public License for more details. * * * * You should have received a copy of the GNU General Public License * * along with this program; if not, see * ***************************************************************************/ #include #include #include #include #include #include #include "nmea_rbuf.h" static inline size_t nmeaRbuf_size(struct nmeaRbuf *rbuf) { if(rbuf->wrPos >= rbuf->rdPos) return rbuf->wrPos - rbuf->rdPos; else return CONFIG_NMEA_RBUF_SIZE + rbuf->wrPos - rbuf->rdPos; } void nmeaRbuf_reset(struct nmeaRbuf *rbuf) { rbuf->wrPos = 0; rbuf->rdPos = 0; rbuf->rdLimit = 0; rbuf->filling = false; } int nmeaRbuf_putChar(struct nmeaRbuf *rbuf, const char c) { if((rbuf->filling == false) && (c == '$')) rbuf->filling = true; if(rbuf->filling) { size_t next = (rbuf->wrPos + 1) % CONFIG_NMEA_RBUF_SIZE; // No more space, drop current sentence and restart if(next == rbuf->rdPos) { rbuf->filling = false; rbuf->wrPos = rbuf->rdLimit; return -1; } // Append the new character rbuf->data[rbuf->wrPos] = c; rbuf->wrPos = next; // Check if a full sentence is present if(c == '\n') { rbuf->filling = false; rbuf->rdLimit = rbuf->wrPos; } } return 0; } int nmeaRbuf_putSentence(struct nmeaRbuf *rbuf, const char *sentence) { size_t len = strlen(sentence); size_t next = (rbuf->wrPos + len) % CONFIG_NMEA_RBUF_SIZE; size_t free = CONFIG_NMEA_RBUF_SIZE - nmeaRbuf_size(rbuf); // Bad-formatted string if((sentence[0] != '$') || (sentence[len - 1] != '\n')) return -1; // Not enough space if(len >= free) return -2; // Handle write pointer wrap-around if((rbuf->wrPos + len) >= CONFIG_NMEA_RBUF_SIZE) { size_t chunkSize = CONFIG_NMEA_RBUF_SIZE - rbuf->wrPos; memcpy(&rbuf->data[rbuf->wrPos], sentence, chunkSize); sentence += chunkSize; len -= chunkSize; rbuf->wrPos = 0; } memcpy(&rbuf->data[rbuf->wrPos], sentence, len); rbuf->wrPos = next; rbuf->rdLimit = next; return 0; } int nmeaRbuf_getSentence(struct nmeaRbuf *rbuf, char *buf, const size_t maxLen) { size_t bufPos = 0; char c; if(rbuf->rdPos == rbuf->rdLimit) return 0; do { // Pop one character from the buffer c = rbuf->data[rbuf->rdPos]; rbuf->rdPos += 1; rbuf->rdPos %= CONFIG_NMEA_RBUF_SIZE; // Store it buf[bufPos] = c; if(bufPos < maxLen) bufPos += 1; } while(c != '\n'); if(bufPos == maxLen) return -1; return (int) bufPos; }