/**************************************************************/
/*  tpax: a topological pax implementation                    */
/*  Copyright (C) 2020--2024  SysDeer Technologies, LLC       */
/*  Released under GPLv2 and GPLv3; see COPYING.TPAX.         */
/**************************************************************/

#include <tpax/tpax.h>
#include "tpax_driver_impl.h"
#include "tpax_errinfo_impl.h"
#include "tpax_visibility_impl.h"

static int tpax_archive_append_memory_data(
	int                             fdout,
	void *                          buf,
	ssize_t                         nbytes)
{
	ssize_t ret;
	char  * ch;

	for (ch=buf; nbytes; ch+=ret) {
		ret = write(fdout,ch,nbytes);

		while ((ret < 0) && (errno == EINTR))
			ret = write(fdout,ch,nbytes);

		if (ret < 0)
			return ret;

		nbytes -= ret;
	}

	return 0;
}

static int tpax_archive_append_pad(
	const struct tpax_driver_ctx *  dctx,
	int                             fdout,
	const struct stat *             st)
{
	int     ret;
	off_t   cpos;
	ssize_t nbytes;
	char    buf[512];

	nbytes  = st->st_size;
	nbytes += 0x1ff;
	nbytes |= 0x1ff;
	nbytes ^= 0x1ff;
	nbytes -= st->st_size;

	memset(buf,0,nbytes);

	cpos  = tpax_get_driver_cpos(dctx);
	cpos += st->st_size + nbytes;

	if (!(ret = tpax_archive_append_memory_data(fdout,buf,nbytes)))
		tpax_set_driver_cpos(dctx,cpos);

	return ret;
}

int tpax_archive_seal(const struct tpax_driver_ctx * dctx)
{
	int     fdout;
	off_t   cpos;
	ssize_t nbytes;
	ssize_t nwritten;
	ssize_t blksize;
	char    buf[512];

	blksize = tpax_get_archive_block_size(dctx);
	cpos    = tpax_get_driver_cpos(dctx);

	if (cpos % 512)
		return TPAX_CUSTOM_ERROR(dctx,TPAX_ERR_FLOW_ERROR);

	fdout = tpax_driver_fdout(dctx);
	memset(buf,0,sizeof(buf));

	switch (cpos % blksize) {
		case 0:
			nbytes = cpos + blksize;
			break;

		default:
			nbytes  = cpos / blksize;
			nbytes *= blksize;
			nbytes += blksize;

			if (nbytes-cpos == 512)
				nbytes += blksize;
	}

	for (nwritten=cpos; nwritten<nbytes; nwritten+=512) {
		if (tpax_archive_append_memory_data(fdout,buf,512) < 0)
			return TPAX_SYSTEM_ERROR(dctx);

		tpax_set_driver_cpos(dctx,nwritten);
	}

	(void)tpax_archive_append_pad;

	return 0;
}