pjs/xpcom/io/nsEscape.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Netscape Public License
 * Version 1.0 (the "NPL"); you may not use this file except in
 * compliance with the NPL.  You may obtain a copy of the NPL at
 * http://www.mozilla.org/NPL/
 *
 * Software distributed under the NPL is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
 * for the specific language governing rights and limitations under the
 * NPL.
 *
 * The Initial Developer of this code under the NPL is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
 * Reserved.
 */
 
//	First checked in on 98/12/03 by John R. McMullen, derived from net.h/mkparse.c.

#include "nsEscape.h"

#include "plstr.h"

const int netCharType[256] =
/*	Bit 0		xalpha		-- the alphas
**	Bit 1		xpalpha		-- as xalpha but 
**                             converts spaces to plus and plus to %20
**	Bit 3 ...	path		-- as xalphas but doesn't escape '/'
*/
    /*   0 1 2 3 4 5 6 7 8 9 A B C D E F */
    {    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,	/* 0x */
		 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,	/* 1x */
		 0,0,0,0,0,0,0,0,0,0,7,4,0,7,7,4,	/* 2x   !"#$%&'()*+,-./	 */
         7,7,7,7,7,7,7,7,7,7,0,0,0,0,0,0,	/* 3x  0123456789:;<=>?	 */
	     0,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,	/* 4x  @ABCDEFGHIJKLMNO  */
	     /* bits for '@' changed from 7 to 0 so '@' can be escaped   */
	     /* in usernames and passwords in publishing.                */
	     7,7,7,7,7,7,7,7,7,7,7,0,0,0,0,7,	/* 5X  PQRSTUVWXYZ[\]^_	 */
	     0,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,	/* 6x  `abcdefghijklmno	 */
	     7,7,7,7,7,7,7,7,7,7,7,0,0,0,0,0,	/* 7X  pqrstuvwxyz{\}~	DEL */
		 0, };

/* decode % escaped hex codes into character values
 */
#define UNHEX(C) \
    ((C >= '0' && C <= '9') ? C - '0' : \
     ((C >= 'A' && C <= 'F') ? C - 'A' + 10 : \
     ((C >= 'a' && C <= 'f') ? C - 'a' + 10 : 0)))


#define IS_OK(C) (netCharType[((unsigned int) (C))] & (mask))
#define HEX_ESCAPE '%'

//----------------------------------------------------------------------------------------
char* nsEscape(const char * str, nsEscapeMask mask)
//----------------------------------------------------------------------------------------
{
    if(!str)
        return NULL;
    return nsEscapeCount(str, (PRInt32)PL_strlen(str), mask, NULL);
}

//----------------------------------------------------------------------------------------
char* nsEscapeCount(const char * str, PRInt32 len, nsEscapeMask mask, PRInt32 * out_len)
//----------------------------------------------------------------------------------------
{
    int32       i, extra = 0;
    char        *hexChars = "0123456789ABCDEF";

	if(!str)
		return(0);

	register const unsigned char* src = (unsigned char *) str;
    for (i = 0; i < len; i++)
	  {
        if (!IS_OK(src[i]))
            extra+=2; /* the escape, plus an extra byte for each nibble */
	  }

	char* result = new char[len + extra + 1];
    if (!result)
        return(0);

    register unsigned char* dst = (unsigned char *) result;
    for (i = 0; i < len; i++)
	  {
		unsigned char c = src[i];
		if (IS_OK(c))
		  {
			*dst++ = c;
		  }
		else if (mask == url_XPAlphas && c == ' ')
		  {
			*dst++ = '+'; /* convert spaces to pluses */
		  }
		else 
		  {
			*dst++ = HEX_ESCAPE;
			*dst++ = hexChars[c >> 4];		/* high nibble */
			*dst++ = hexChars[c & 0x0f];	/* low nibble */
		  }
	  }

    *dst = '\0';     /* tack on eos */
	if(out_len)
		*out_len = dst - (unsigned char *) result;
    return result;
}

//----------------------------------------------------------------------------------------
char* nsUnescape(char * str)
//----------------------------------------------------------------------------------------
{
	nsUnescapeCount(str);
	return str;
}

//----------------------------------------------------------------------------------------
PRInt32 nsUnescapeCount(char * str)
//----------------------------------------------------------------------------------------
{
    register char *src = str;
    register char *dst = str;

    while (*src)
        if (*src != HEX_ESCAPE)
		  {
        	*dst++ = *src++;
		  }
        else 	
		  {
        	src++; /* walk over escape */
        	if (*src)
              {
            	*dst = UNHEX(*src) << 4;
            	src++;
              }
        	if (*src)
              {
            	*dst = (*dst + UNHEX(*src));
            	src++;
              }
        	dst++;
          }

    *dst = 0;

    return (int)(dst - str);

} /* NET_UnEscapeCnt */