HardFault/Middlewares/elog/elog.c

#include <elog.h>

#include <string.h>

elog_t *elog_init(void *arena, size_t size)
{
    elog_t *ptr = (elog_t *)arena;
    ptr->buflen = size - sizeof(elog_t); // Adjust for the size of the elog_t structure
    ptr->offset = 0;
    return ptr;
}

int elog_put(elog_t *log, const char *const msg, int n, msgparam_t args[])
{
    elog_entry_t *e = (elog_entry_t *)(log->buffer + log->offset); // 计算当前可写的位置e（即log->buffer）
    long esize = n * sizeof(msgparam_t); // 参数占用字节数
    long newoff = log->offset + sizeof(elog_entry_t) + esize; // 计算新的偏移量，开始是elog_entry_t头 + n个msg（id和长度组成）

    if (newoff < log->buflen)
    {
        e->msgid = MSGPTR_MAKE(n, (msgptr_t)msg); // 通过字符串地址和个数生成msgid，并写入e
        memcpy(e->data, args, esize); // 参数列表写入e
        log->offset = newoff;
        return 1;
    }

    return 0;
}

void elog_flush(elog_t *log, elog_flush_func_t func, void *ctx)
{
    long off = 0;

    while (off < log->offset) // 也可以直接发送出去上位机，在上位机端解码
    {
        elog_entry_t *e = ((elog_entry_t *)(log->buffer + off));
        size_t len = MSGPTR_LEN(e->msgid) * sizeof(long);
        size_t incr = sizeof(elog_entry_t) + len;
        off += incr;
        func(e, incr, ctx); // 解出一个e[id + data]
    }

    log->offset = 0;
}