ObjFW  Artifact [9b57fed9b2]

Artifact 9b57fed9b20cdfe6d967690ddf04a010a855ba6d55f26b80bfc233e4d25f66c8:

• File src/OFString+URLEncoding.m — part of check-in [516517deb3] at 2016-08-21 14:00:20 on branch trunk — OFURL: Do not URL decode and reencode parts

  URL decoding and reencoding is not lossless: For example, if the query
  was foo=bar&qux=foo%25bar, it will be decoded to foo=bar&qux=foo&bar and
  then reencoded to foo=bar%25qux=foo%25bar, which is a different thing.

  The only way to solve this is to let the application handle the URL
  decoding and encoding according to its own rules, as those might be
  different depending on the application. (user: js, size: 3583) [annotate] [blame] [check-ins using]

/*
 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016
 *   Jonathan Schleifer <js@heap.zone>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *
 * Alternatively, it may be distributed under the terms of the GNU General
 * Public License, either version 2 or 3, which can be found in the file
 * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
 * file.
 */

#include "config.h"

#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#import "OFString+URLEncoding.h"

#import "OFInvalidFormatException.h"
#import "OFOutOfMemoryException.h"

/* Reference for static linking */
int _OFString_URLEncoding_reference;

@implementation OFString (URLEncoding)
- (OFString*)stringByURLEncoding
{
	return [self stringByURLEncodingWithAllowedCharacters: "$-_.!*()"];
}

- (OFString*)stringByURLEncodingWithAllowedCharacters: (const char*)allowed
{
	void *pool = objc_autoreleasePoolPush();
	const char *string = [self UTF8String];
	char *retCString;
	size_t i;
	OFString *ret;

	/*
	 * Worst case: 3 times longer than before.
	 * Oh, and we can't use [self allocWithSize:] here as self might be a
	 * @"" literal.
	 */
	if ((retCString = malloc(([self UTF8StringLength] * 3) + 1)) == NULL)
		@throw [OFOutOfMemoryException exceptionWithRequestedSize:
		    ([self UTF8StringLength] * 3) + 1];

	for (i = 0; *string != '\0'; string++) {
		unsigned char c = *string;

		/*
		 * '+' is also listed in RFC 1738, however, '+' is sometimes
		 * interpreted as space in HTTP. Therefore always escape it to
		 * make sure it's always interpreted correctly.
		 */
		if (!(c & 0x80) && (isalnum(c) || strchr(allowed, c) != NULL))
			retCString[i++] = c;
		else {
			unsigned char high, low;

			high = c >> 4;
			low = c & 0x0F;

			retCString[i++] = '%';
			retCString[i++] =
			    (high > 9 ? high - 10 + 'A' : high + '0');
			retCString[i++] =
			    (low  > 9 ? low  - 10 + 'A' : low  + '0');
		}
	}

	objc_autoreleasePoolPop(pool);

	@try {
		ret = [OFString stringWithUTF8String: retCString
					      length: i];
	} @finally {
		free(retCString);
	}

	return ret;
}

- (OFString*)stringByURLDecoding
{
	void *pool = objc_autoreleasePoolPush();
	OFString *ret;
	const char *string = [self UTF8String];
	char *retCString;
	char byte = 0;
	int state = 0;
	size_t i;

	if ((retCString = malloc([self UTF8StringLength] + 1)) == NULL)
		@throw [OFOutOfMemoryException
		    exceptionWithRequestedSize: [self UTF8StringLength] + 1];

	for (i = 0; *string; string++) {
		switch (state) {
		case 0:
			if (*string == '%')
				state = 1;
			else
				retCString[i++] = *string;
			break;
		case 1:
		case 2:;
			uint8_t shift = (state == 1 ? 4 : 0);

			if (*string >= '0' && *string <= '9')
				byte += (*string - '0') << shift;
			else if (*string >= 'A' && *string <= 'F')
				byte += (*string - 'A' + 10) << shift;
			else if (*string >= 'a' && *string <= 'f')
				byte += (*string - 'a' + 10) << shift;
			else {
				free(retCString);
				@throw [OFInvalidFormatException exception];
			}

			if (++state == 3) {
				retCString[i++] = byte;
				state = 0;
				byte = 0;
			}

			break;
		}
	}
	retCString[i] = '\0';

	objc_autoreleasePoolPop(pool);

	if (state != 0) {
		free(retCString);
		@throw [OFInvalidFormatException exception];
	}

	@try {
		ret = [OFString stringWithUTF8String: retCString
					      length: i];
	} @finally {
		free(retCString);
	}
	return ret;
}
@end