/*

 * Copyright (C) 2014  J. Ali Harlow <ali@juiblex.co.uk>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License along

 * with this program; if not, write to the Free Software Foundation, Inc.,

 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

#include "config.h"

#include <stdlib.h>

#include <string.h>

#include "razor.h"

#include "razor-internal.h"

/**

 * razor_path_add_root:

 *

 * Adds a root to a path. path must be an absolute pathname. In POSIX

 * environments this is equivalent to the concationation of root and path.

 * In Microsoft Windows an adjustment may need to be made for a drive letter

 * in path (which will be dropped).

 *

 * Returns: The new pathname.

 **/

RAZOR_EXPORT char *razor_path_add_root(const char *path, const char *root)

{

	if (root && *root)

		return razor_concat(root, SKIP_DRIVE_LETTER(path), NULL);

	else

		return strdup(path);

}

#if 0

/*

 * This should work, but for some reason PathCreateFromUrlW()

 * treats the percent-encoded bytes as being in CP 850 rather

 * than UTF-8 as expected even if we set the codepage.

 */

RAZOR_EXPORT char *razor_path_from_url(const char *url)

{

	UINT saved_cp;

	HRESULT result;

	DWORD len = MAX_PATH;

	wchar_t *url16;

	wchar_t path16[MAX_PATH];

	char *path;

	url16 = razor_utf8_to_utf16(url, -1);

	saved_cp = GetConsoleCP();

	SetConsoleCP(CP_UTF8);

	result = PathCreateFromUrlW(url16, path16, &len, NULL);

	SetConsoleCP(saved_cp);

	if (result == S_OK)

		path = razor_utf16_to_utf8(path16, len);

	else

		path = NULL;

	free(url16);

	return path;

}

#else

#ifdef MSWIN_API

static int is_ascii_letter(char c)

{

	return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');

}

#endif

static int xdigit_value(char c)

{

	if (c >= '0' && c <= '9')

		return c - '0';

	else

		return (c | 0x20) - 'a' + 10;

}

static int valid_unicode(unsigned unicode)

{

	/*

	 * Within the U+0000..U+10FFFF range defined by RFC3629

	 * but not in the U+D800..U+DFFF range prohibited in UTF-8.

	 */

	return unicode < 0xD800 || (unicode >= 0xE000 && unicode < 0x110000);

}

RAZOR_EXPORT char *razor_path_from_url(const char *url)

{

	int continuation_bytes = 0;

	char *path, *p;

	unsigned char c;

	unsigned unicode;

	if (strncmp(url, "file://", 7) == 0)

		url += 7;

	else

		return NULL;

	if (strncmp(url, "localhost/", 10) == 0)

		url += 9;

	else if (strncmp(url, "/", 1) != 0)

		return NULL;

#ifdef MSWIN_API

	/*

	 * Under MS-Windows, file:///c:/xxx maps to c:/xxx

	 * Note that PathCreateFromUrl converts / to \ as well.

	 */

	if (is_ascii_letter(url[1]) && url[2] == ':' && url[3] == '/')

		url++;

#endif

	p = path = malloc(strlen(url) + 1);

	while(*url) {

		if (*url >= 0x7F || *url < 0x20) {

			free(path);

			return NULL;

		} else if (*url != '%') {

			if (continuation_bytes) {

				free(path);

				return NULL;

			} else

				*p++ = *url++;

		} else if (isxdigit(url[1]) && isxdigit(url[2])) {

			c = xdigit_value(url[1]) * 16 + xdigit_value(url[2]);

			if (c == '/') {

				free(path);

				return NULL;

			} else if (!continuation_bytes) {

				if (c >= 0xF5 || c == 0xC0 || c == 0xC1) {

					free(path);

					return NULL;

				} else if (c >= 0xF0) {

					unicode = c & 7;

					continuation_bytes = 3;

				} else if (c >= 0xE0) {

					unicode = c & 3;

					continuation_bytes = 2;

				} else if (c >= 0xC0) {

					unicode = c & 1;

					continuation_bytes = 1;

				}

			} else if ((c & 0xC0) != 0x80) {

				free(path);

				return NULL;

			} else {

				unicode <<= 6;

				unicode |= (c & 0x3F);

				if (!--continuation_bytes &&

				    !valid_unicode(unicode)) {

					free(path);

					return NULL;

				}

			}

			*p++ = c;

			url += 3;

		} else {

			free(path);

			return NULL;

		}

	}

	if (continuation_bytes) {

		free(path);

		return NULL;

	}

	*p++ = '\0';

	return realloc(path, p - path);

}

#endif	/* 0 */