Function PAG_add_header_entry

src/jrd/pag.cpp:338–403

bool PAG_add_header_entry(thread_db* tdbb, header_page* header,
						 USHORT type, USHORT len, const UCHAR* entry)
{
/***********************************************
 *
 *	P A G _ a d d _ h e a d e r _ e n t r y
 *
 ***********************************************
 *
 * Functional description
 *	Add an entry to header page.
 *	This will be used mainly for the shadow header page and adding
 *	secondary files.
 *	Will not follow to hdr_next_page
 *	Will not journal changes made to page. => obsolete
 *	RETURNS
 *		true - modified page
 *		false - nothing done
 * CVC: Nobody checks the result of this function!
 *
 **************************************/
	SET_TDBB(tdbb);
	Database* dbb = tdbb->getDatabase();
	CHECK_DBB(dbb);

	err_post_if_database_is_readonly(dbb);

	UCHAR* p = header->hdr_data;
	while (*p != HDR_end && *p != type)
		p += 2u + p[1];

	if (*p != HDR_end)
		return false;

	// We are at HDR_end, add the entry

	const int free_space = dbb->dbb_page_size - header->hdr_end;

	if (free_space > (2 + len))
	{
		fb_assert(type <= MAX_UCHAR);
		fb_assert(len <= MAX_UCHAR);
		*p++ = static_cast<UCHAR>(type);
		*p++ = static_cast<UCHAR>(len);

		if (len)
		{
			if (entry) {
				memcpy(p, entry, len);
			}
			else {
				memset(p, 0, len);
			}
			p += len;
		}

		*p = HDR_end;