GC19038/Component/NodeLink/NodeLinkCommon.c

#include "NodeLinkCommon.h"
#include "MathHelper.h"


/**
 * 数据编码
 * 
 * @author lxz (041820 14:21:27)
 * 
 * @param slave 
 * @param dst 
 * @param src 
 * @param len 
 * 
 * @return int 
 */
int nodelink_decode(unsigned char *id, unsigned char *dst, unsigned char *src, int len) { 
    int res = 0;
    if (len >= 4) {
        *id = src[0] & 0xf0;
        while (len > 1) {
            dst[res] = ((src[res * 2] & 0x0f) << 4) + ((src[res * 2 + 1] & 0x0f));
            res++;
            len -= 2;
        }
        if (mh_crc8_calc(dst, res) == 0) {
            return res - 1;
        }
    }
    return 0;
}
/**
 * 数据解码
 * 
 * @author lxz (041820 14:22:05)
 * 
 * @param id 
 * @param dst 
 * @param src 
 * @param len 
 * 
 * @return int 
 */
int nodelink_encode(char id, unsigned char *dst, unsigned char *src, int len) {
    int res = 0;
    unsigned char crc = 0;
    crc = mh_crc8_calc(src, len);
    res = (len + 1) * 2;
    dst[len * 2] = ((crc >> 4) & 0x0f) | id;
    dst[len * 2 + 1] = (crc & 0x0f) | id;
    while (len--) {
        dst[len * 2 + 1] = (src[len] & 0x0f) | id;
        dst[len * 2] = ((src[len] >> 4) & 0x0f) | id;
    }
    return res;
}