Function pbuf_take_at

components/net/lwip/lwip-2.1.2/src/core/pbuf.c:1239–1262

* @ingroup pbuf * Same as pbuf_take() but puts data at an offset * * @param buf pbuf to fill with data * @param dataptr application supplied data buffer * @param len length of the application supplied data buffer * @param offset offset in pbuf where to copy dataptr to * * @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_at(struct pbuf *buf, const void *dataptr, u16_t len, u16_t offset)
{
  u16_t target_offset;
  struct pbuf *q = pbuf_skip(buf, offset, &target_offset);

  /* return requested data if pbuf is OK */
  if ((q != NULL) && (q->tot_len >= target_offset + len)) {
    u16_t remaining_len = len;
    const u8_t *src_ptr = (const u8_t *)dataptr;
    /* copy the part that goes into the first pbuf */
    u16_t first_copy_len;
    LWIP_ASSERT("check pbuf_skip result", target_offset < q->len);
    first_copy_len = (u16_t)LWIP_MIN(q->len - target_offset, len);
    MEMCPY(((u8_t *)q->payload) + target_offset, dataptr, first_copy_len);
    remaining_len = (u16_t)(remaining_len - first_copy_len);
    src_ptr += first_copy_len;
    if (remaining_len > 0) {
      return pbuf_take(q->next, src_ptr, remaining_len);
    }
    return ERR_OK;
  }
  return ERR_MEM;
}

/**
 * @ingroup pbuf