Function pbuf_take

components/net/lwip/lwip-2.1.2/src/core/pbuf.c:1195–1226

* @ingroup pbuf * Copy application supplied data into a pbuf. * This function can only be used to copy the equivalent of buf->tot_len data. * * @param buf pbuf to fill with data * @param dataptr application supplied data buffer * @param len length of the application supplied data buffer * * @return ERR_OK if successful, ERR_MEM if the pbuf is not big enough */

 * @return ERR_OK if successful, ERR_MEM if the pbuf is not big enough
 */
err_t
pbuf_take(struct pbuf *buf, const void *dataptr, u16_t len)
{
  struct pbuf *p;
  size_t buf_copy_len;
  size_t total_copy_len = len;
  size_t copied_total = 0;

  LWIP_ERROR("pbuf_take: invalid buf", (buf != NULL), return ERR_ARG;);
  LWIP_ERROR("pbuf_take: invalid dataptr", (dataptr != NULL), return ERR_ARG;);
  LWIP_ERROR("pbuf_take: buf not large enough", (buf->tot_len >= len), return ERR_MEM;);

  if ((buf == NULL) || (dataptr == NULL) || (buf->tot_len < len)) {
    return ERR_ARG;
  }

  /* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */
  for (p = buf; total_copy_len != 0; p = p->next) {
    LWIP_ASSERT("pbuf_take: invalid pbuf", p != NULL);
    buf_copy_len = total_copy_len;
    if (buf_copy_len > p->len) {
      /* this pbuf cannot hold all remaining data */
      buf_copy_len = p->len;
    }
    /* copy the necessary parts of the buffer */
    MEMCPY(p->payload, &((const char *)dataptr)[copied_total], buf_copy_len);
    total_copy_len -= buf_copy_len;
    copied_total += buf_copy_len;
  }
  LWIP_ASSERT("did not copy all data", total_copy_len == 0 && copied_total == len);
  return ERR_OK;
}

/**
 * @ingroup pbuf