/**************************************************************/

/*  tpax: a topological pax implementation                    */

/*  Copyright (C) 2020--2024  SysDeer Technologies, LLC       */

/*  Released under GPLv2 and GPLv3; see COPYING.TPAX.         */

/**************************************************************/

#include <stdint.h>

#include <stdlib.h>

#include <string.h>

#include <errno.h>

#include <sys/stat.h>

#include <tpax/tpax.h>

#include "tpax_driver_impl.h"

int tpax_util_path_copy(

	char *          dstpath,

	const char *    srcpath,

	size_t          bufsize,

	uint32_t        flags,

	size_t *        nwritten)

{

	const char *    src;

	char *          dst;

	char *          cap;

	if (!bufsize) {

		errno = ENOBUFS;

		return -1;

	}

	src = srcpath;

	dst = dstpath;

	cap = &dst[bufsize];

	if ((src[0] == '/') && (src[1] == '/') && (src[2] != '/')) {

		*dst++ = *src++;

		*dst++ = *src++;

	}

	if (flags & TPAX_DRIVER_PURE_PATH_OUTPUT)

		if ((src[0] == '.') && (src[1] == '/'))

			for (++src; *src=='/'; src++)

				(void)0;

	for (; *src; ) {

		if ((src[0] == '.') && (src[1] == '.')) {

			if ((src[2] == '/') || (src[2] == '\0')) {

				if (flags & TPAX_DRIVER_STRICT_PATH_INPUT) {

					errno = EINVAL;

					return -1;

				}

			}

		}

		if (flags & TPAX_DRIVER_PURE_PATH_OUTPUT) {

			if ((src[0] == '.') && (src[1] == '/') && (src[-1] == '/')) {

				for (++src; *src=='/'; src++)

					(void)0;

			} else if ((src[0] == '/')) {

				for (src++; *src=='/'; src++)

					(void)0;

				*dst++ = '/';

			} else {

				*dst++ = *src++;

			}

		} else {

			*dst++ = *src++;

		}

		if (dst == cap) {

			errno = ENOBUFS;

			return -1;

		}

	}

	if (nwritten)

		*nwritten = dst - dstpath;

	*dst = '\0';

	return 0;

}