Mine

typedef struct{  void*   data;   /* pointer to buffer */  size_t  size;   /* size of buffer */  void*   head;   /* point at which data is added */  void*   tail;   /* point at which data is removed */} cbuf;void cbuf_init(cbuf* buf, void* data, size_t size){  buf->data = data;  buf->size = size;  buf->head = data;  buf->tail = data;}void cbuf_add(cbuf* dst, const void* src, size_t src_size){  size_t dst_remaining = ((char*)dst->data - (char*)dst->head) + dst->size;  if(dst_remaining > src_size)  { /* copy src to buffer, head doesnt wrap */    memcpy(dst->head, src, src_size);    dst->head = (char*)dst->head + src_size;  }  else  { /* head wraps, perform 2 copies */    memcpy(dst->head, src, dst_remaining);    dst->head = dst->data;    if(((char*)dst->head + src_size - dst_remaining) > dst->tail)    {      printf("BUFFER FULL!!!!!!!\r\n");    }    else    {      memcpy(dst->head, (char*)src + dst_remaining, src_size - dst_remaining);    }  }}