keytag.c

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#include "keytag.h"

#include <cfg/debug.h>
// Define log settings for cfg/log.h
#define LOG_LEVEL    CONFIG_KEYTAG_LOG_LEVEL
#define LOG_FORMAT   CONFIG_KEYTAG_LOG_FORMAT
#include <cfg/log.h>
#include <cfg/macros.h>

#include <io/kfile.h>

#include <string.h>
#define TAG_STX 0x02

#define TAG_ETX 0x03

static void keytag_clearPkt(struct TagPacket *pkt)
{
    pkt->sync = false;
    pkt->len = 0;
}

void keytag_poll(struct TagPacket *pkt)
{
    uint8_t buf[CONFIG_TAG_MAX_LEN];
    int len;
    if ((len = keytag_recv(pkt, buf, sizeof(buf))) != EOF)
        kfile_write(pkt->host, buf, len);
}

int keytag_recv(struct TagPacket *pkt, uint8_t *tag, size_t len)
{
    int c;

    /* Get all chars from buffer */
    while ((c = kfile_getc(pkt->tag)) != EOF)
    {
        /* Search for STX char in received chars */
        if (c == TAG_STX)
        {
            /* When STX is found a new packet begins */
            if (pkt->sync)
                LOG_WARN("TAG double sync!\n");
            keytag_clearPkt(pkt);
            pkt->sync = true;
        }
        else if (pkt->sync)
        {
            /* Check for end of packet */
            if (c == TAG_ETX)
            {
                /* Terminate the tag string */
                size_t tag_len = MIN(len, pkt->len);

                /* Save read tag */
                memcpy(tag, pkt->buf, tag_len);
                pkt->sync = false;
                return tag_len;
            }
            else
            {
                /* Check for buffer overflow */
                if (pkt->len >= CONFIG_TAG_MAX_LEN)
                {
                    LOG_ERR("TAG buffer overflow\n");
                    pkt->sync = false;
                }
                else
                {
                    /* Add every char after STX to tag reading buffer */
                    if (pkt->sync)
                    {
                        pkt->buf[pkt->len] = c;
                        pkt->len++;
                    }
                }
            }
        }
    }
    if (kfile_error(pkt->tag) != 0)
    {
        LOG_ERR("Error %04x\n", kfile_error(pkt->tag));
        kfile_clearerr(pkt->tag);
    }

    return EOF;
}

void keytag_init(struct TagPacket *pkt, struct KFile *comm, struct KFile *tag)
{
    keytag_clearPkt(pkt);
    pkt->tag = tag;
    pkt->host = comm;
}