/* This file (and HTParse.h) taken from w3c-libwww-5.1i/Library/src */

/*
Copyright 1997 World Wide Web Consortium, (Massachusetts Institute of
Technology, Institut National de Recherche en Informatique et en
Automatique, Keio University). All Rights Reserved.

THIS SOFTWARE AND DOCUMENTATION IS PROVIDED "AS IS," AND COPYRIGHT
HOLDERS MAKE NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO, WARRANTIES OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF THE SOFTWARE OR
DOCUMENTATION WILL NOT INFRINGE ANY THIRD PARTY PATENTS, COPYRIGHTS,
TRADEMARKS OR OTHER RIGHTS.

COPYRIGHT HOLDERS WILL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL
OR CONSEQUENTIAL DAMAGES ARISING OUT OF ANY USE OF THE SOFTWARE OR
DOCUMENTATION.
*/


/*								      HTParse.c
**	URI MANAGEMENT
**
**	(c) COPYRIGHT MIT 1995.
**	Please first read the full copyright statement in the file COPYRIGH.
**	@(#) $Id: HTParse.c,v 1.4 1998/07/07 06:23:22 tromey Exp $
**
** history:
**	May 12 94	TAB added as legal char in HTCleanTelnetString
**
*/

#define GHELP
#if defined(GHELP)
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#define PRIVATE static
#define PUBLIC
#define BOOL char
#define URI_TRACE 0
#define YES 1
#define NO 0
#define HTTrace printf
#define HT_MALLOC malloc
#define HT_CALLOC calloc
#define HT_OUTOFMEM perror
#define HT_FREE free
#define TOLOWER tolower
#define TOASCII toascii
#define strcasecomp strcasecmp
#define scan HTScan

#define StrAllocCopy(dest, src) HTSACopy (&(dest), src)

/* From HTString.c */
/*	Allocate a new copy of a string, and returns it
*/
PUBLIC char * HTSACopy (char ** dest, const char * src)
{
  if (*dest) HT_FREE(*dest);
  if (! src)
    *dest = NULL;
  else {
    if ((*dest  = (char  *) HT_MALLOC(strlen(src) + 1)) == NULL)
        HT_OUTOFMEM("HTSACopy");
    strcpy (*dest, src);
  }
  return *dest;
}

#else
/* Library include files */
#include "sysdep.h"
#include "WWWUtil.h"
#endif

#include "HTParse.h"					 /* Implemented here */

#if !defined(GHELP)
typedef struct _HTURI {
    char * access;		/* Now known as "scheme" */
    char * host;
    char * absolute;
    char * relative;
    char * fragment;
} HTURI;
#endif

/*	Scan a filename for its consituents
**	-----------------------------------
**
** On entry,
**	name	points to a document name which may be incomplete.
** On exit,
**      absolute or relative may be nonzero (but not both).
**	host, fragment and access may be nonzero if they were specified.
**	Any which are nonzero point to zero terminated strings.
*/
#if defined(GHELP)
PUBLIC void scan (char * name, HTURI * parts)
#else
PRIVATE void scan (char * name, HTURI * parts)
#endif
{
    char * p;
    char * after_access = name;
    memset(parts, '\0', sizeof(HTURI));

    /* Look for fragment identifier */
    if ((p = strchr(name, '#')) != NULL) {
	*p++ = '\0';
	parts->fragment = p;
    }
    
    /* 
    ** Look for any spaces. This is very bad for pipelining as it
    ** makes the request invalid
    */
    if ((p = strchr(name, ' ')) != NULL) *p++ = '\0';
    
    for(p=name; *p; p++) {
	if (*p=='/' || *p=='#' || *p=='?')
	    break;
	if (*p==':') {
		*p = 0;
		parts->access = after_access; /* Scheme has been specified */

/* The combination of gcc, the "-O" flag and the HP platform is
   unhealthy. The following three lines is a quick & dirty fix, but is
   not recommended. Rather, turn off "-O". */

/*		after_access = p;*/
/*		while (*after_access == 0)*/
/*		    after_access++;*/

		after_access = p+1;

		if (0==strcasecomp("URL", parts->access)) {
		    parts->access = NULL;  /* Ignore IETF's URL: pre-prefix */
		} else break;
	}
    }
    
    p = after_access;
    if (*p=='/'){
	if (p[1]=='/') {
	    parts->host = p+2;		/* host has been specified 	*/
	    *p=0;			/* Terminate access 		*/
	    p=strchr(parts->host,'/');	/* look for end of host name if any */
	    if(p) {
	        *p=0;			/* Terminate host */
	        parts->absolute = p+1;		/* Root has been found */
	    }
	} else {
	    parts->absolute = p+1;		/* Root found but no host */
	}	    
    } else {
        parts->relative = (*after_access) ? after_access : 0; /* zero for "" */
    }
}


/*	Parse a Name relative to another name
**	-------------------------------------
**
**	This returns those parts of a name which are given (and requested)
**	substituting bits from the related name where necessary.
**
** On entry,
**	aName		A filename given
**      relatedName     A name relative to which aName is to be parsed. Give
**                      it an empty string if aName is absolute.
**      wanted          A mask for the bits which are wanted.
**
** On exit,
**	returns		A pointer to a malloc'd string which MUST BE FREED
*/
PUBLIC char * HTParse (const char *aName, const char *relatedName, int wanted)
{
    char * result = 0;
    char * return_value = 0;
    int len;
    char * name = 0;
    char * rel = 0;
    char * p;
    char * access;
    HTURI given, related;
    
    if (!relatedName)        /* HWL 23/8/94: dont dump due to NULL */
        relatedName = "";
    
    /* Make working copies of input strings to cut up: */
    len = strlen(aName)+strlen(relatedName)+10;
    if ((result=(char *) HT_MALLOC(len)) == NULL) /* Lots of space: more than enough */
	HT_OUTOFMEM("parse space");
    StrAllocCopy(name, aName);
    StrAllocCopy(rel, relatedName);
    
    scan(name, &given);
    scan(rel,  &related); 
    result[0]=0;		/* Clear string  */
    access = given.access ? given.access : related.access;
    if (wanted & PARSE_ACCESS)
        if (access) {
	    strcat(result, access);
	    if(wanted & PARSE_PUNCTUATION) strcat(result, ":");
	}
	
    if (given.access && related.access)	/* If different, inherit nothing. */
        if (strcmp(given.access, related.access)!=0) {
	    related.host=0;
	    related.absolute=0;
	    related.relative=0;
	    related.fragment=0;
	}
	
    if (wanted & PARSE_HOST)
        if(given.host || related.host) {
	    if(wanted & PARSE_PUNCTUATION) strcat(result, "//");
	    strcat(result, given.host ? given.host : related.host);
	}
	
    if (given.host && related.host)  /* If different hosts, inherit no path. */
        if (strcmp(given.host, related.host)!=0) {
	    related.absolute=0;
	    related.relative=0;
	    related.fragment=0;
	}
	
    if (wanted & PARSE_PATH) {
        if(given.absolute) {				/* All is given */
	    if(wanted & PARSE_PUNCTUATION) strcat(result, "/");
	    strcat(result, given.absolute);
	} else if(related.absolute) {	/* Adopt path not name */
	    strcat(result, "/");
	    strcat(result, related.absolute);
	    if (given.relative) {
		p = strchr(result, '?');	/* Search part? */
		if (!p) p=result+strlen(result)-1;
		for (; *p!='/'; p--);	/* last / */
		p[1]=0;					/* Remove filename */
		strcat(result, given.relative);		/* Add given one */
#if 0
		result = HTSimplify (&result);
#endif
	    }
	} else if(given.relative) {
	    p = result + strlen(result);
	    if (*p != '/') {
		strcat(result, "/");
	    }
	    strcat(result, given.relative);		/* what we've got */
	} else if(related.relative) {
	    strcat(result, related.relative);
	} else {  /* No inheritance */
	    strcat(result, "/");
	}
    }
		
    if (wanted & PARSE_ANCHOR)
	if(given.fragment || related.fragment) {
	    if(given.absolute && given.fragment) {   /*Fixes for relURLs...*/
		if(wanted & PARSE_PUNCTUATION) strcat(result, "#");
		strcat(result, given.fragment); 
	    } else if (!(given.absolute) && !(given.fragment)) {
		strcat(result, "");
	    } else {
		if(wanted & PARSE_PUNCTUATION) strcat(result, "#");
		strcat(result, given.fragment ? given.fragment : related.fragment); 
	    }
	}
    HT_FREE(rel);
    HT_FREE(name);
    
    StrAllocCopy(return_value, result);
    HT_FREE(result);
    return return_value;		/* exactly the right length */
}


/*
**	Canonicalizes the URL in the following manner starting from the host
**	pointer:
**
**	1) The host name is converted to lowercase
**	2) Chop off port if `:80' (http), `:70' (gopher), or `:21' (ftp)
**
**	Return: OK	The position of the current path part of the URL
**			which might be the old one or a new one.
*/
PRIVATE char * HTCanon (char ** filename, char * host)
{
    char *newname = NULL;
    char *port;
    char *strptr;
    char *path;
    char *access = host-3;

    while (access>*filename && *(access-1)!='/')       /* Find access method */
	access--;
    if ((path = strchr(host, '/')) == NULL)			/* Find path */
	path = host + strlen(host);
    if ((strptr = strchr(host, '@')) != NULL && strptr<path)	   /* UserId */
	host = strptr;
    if ((port = strchr(host, ':')) != NULL && port>path)      /* Port number */
	port = NULL;

    strptr = host;				    /* Convert to lower-case */
    while (strptr<path) {
	*strptr = TOLOWER(*strptr);
	strptr++;
    }
    
    /* Does the URL contain a full domain name? This also works for a
       numerical host name. The domain name is already made lower-case
       and without a trailing dot. */
#if 0
    if (((strptr = strchr(host, '.')) == NULL || strptr >= path) &&
	strncasecomp(host, "localhost", 9)) {
	const char *domain = HTGetDomainName();
	if (domain && *domain) {
	    if ((newname = (char *) HT_CALLOC(1, strlen(*filename) + strlen(domain)+2)) == NULL)
		HT_OUTOFMEM("HTCanon");
	    if (port)
		strncpy(newname, *filename, (int) (port-*filename));
	    else
		strncpy(newname, *filename, (int) (path-*filename));
	    strcat(newname, ".");
	    strcat(newname, domain);
	}
    } else 					  /* Look for a trailing dot */
#endif
    {
	char *dot = port ? port : path;
	if (dot > *filename && *--dot=='.') {
	    char *orig=dot, *dest=dot+1;
	    while((*orig++ = *dest++));
	    if (port) port--;
	    path--;
	}
    }
    /* Chop off port if `:', `:80' (http), `:70' (gopher), or `:21' (ftp) */
    if (port) {
	if (!*(port+1) || *(port+1)=='/') {
	    if (!newname) {
		char *orig=port, *dest=port+1;
		while((*orig++ = *dest++));
	    }
	} else if ((!strncmp(access, "http", 4) &&
	     (*(port+1)=='8'&&*(port+2)=='0'&&(*(port+3)=='/'||!*(port+3)))) ||
	    (!strncmp(access, "gopher", 6) &&
	     (*(port+1)=='7'&&*(port+2)=='0'&&(*(port+3)=='/'||!*(port+3)))) ||
	    (!strncmp(access, "ftp", 3) &&
	     (*(port+1)=='2'&&*(port+2)=='1'&&(*(port+3)=='/'||!*(port+3))))) {
	    if (!newname) {
		char *orig=port, *dest=port+3;
		while((*orig++ = *dest++));
		path -= 3;   	       /* Update path position, Henry Minsky */
	    }
	} else if (newname)
	    strncat(newname, port, (int) (path-port));
    }

    if (newname) {
	char *newpath = newname+strlen(newname);
	strcat(newname, path);
	path = newpath;
	HT_FREE(*filename);				    /* Free old copy */
	*filename = newname;
    }
    return path;
}

/*
**  Search the URL and determine whether it is a relative or absolute URL.
**  We check to see if there is a ":" before any "/", "?", and "#". If this
**  is the case then we say it is absolute. Otherwise it is relative.
*/
PUBLIC BOOL HTURL_isAbsolute (const char * url)
{    
    if (url) {	
	const char * ptr = url;
	while (*ptr) {
	    if (*ptr == ':') return YES;
	    if (*ptr == '/' || *ptr == '?' || *ptr == '#') break;
	    ptr ++;
	}
    }	
    return NO;
}

/*	        Simplify a URI
//		--------------
// A URI is allowed to contain the seqeunce xxx/../ which may be
// replaced by "" , and the seqeunce "/./" which may be replaced by "/".
// Simplification helps us recognize duplicate URIs. 
//
//	Thus, 	/etc/junk/../fred 	becomes	/etc/fred
//		/etc/junk/./fred	becomes	/etc/junk/fred
//
//      but we should NOT change
//		http://fred.xxx.edu/../..
//
//	or	../../albert.html
//
// In order to avoid empty URLs the following URLs become:
//
//		/fred/..		becomes /fred/..
//		/fred/././..		becomes /fred/..
//		/fred/.././junk/.././	becomes /fred/..
//
// If more than one set of `://' is found (several proxies in cascade) then
// only the part after the last `://' is simplified.
//
// Returns: A string which might be the old one or a new one.
*/
PUBLIC char *HTSimplify (char ** url)
{
    char *path;
    char *p;
    if (!url || !*url) {
	if (URI_TRACE) HTTrace("HTSimplify.. Nothing done\n");
	return *url;
    }
    if (URI_TRACE) HTTrace("HTSimplify.. `%s\' ", *url);

    /* Find any scheme name */
    if ((path = strstr(*url, "://")) != NULL) {		   /* Find host name */
	char *newptr;
	char *access = *url;
	while (access<path && (*access=TOLOWER(*access))) access++;
	path += 3;
	while ((newptr = strstr(path, "://")) != NULL)        /* For proxies */
	    path = newptr+3;
	path = HTCanon(url, path);       	      /* We have a host name */
    } else if ((path = strstr(*url, ":/")) != NULL) {
	path += 2;
    } else
	path = *url;
    if (*path == '/' && *(path+1)=='/') {	  /* Some URLs start //<foo> */
	path += 1;
    } else if (!strncmp(path, "news:", 5)) {
	char *ptr = strchr(path+5, '@');
	if (!ptr) ptr = path+5;
	while (*ptr) {			    /* Make group or host lower case */
	    *ptr = TOLOWER(*ptr);
	    ptr++;
	}
	if (URI_TRACE)
	    HTTrace("into\n............ `%s'\n", *url);
	return *url;		      /* Doesn't need to do any more */
    }
    if ((p = path)) {
	char *end;
	if (!((end = strchr(path, ';')) || (end = strchr(path, '?')) ||
	      (end = strchr(path, '#'))))
	    end = path+strlen(path);

	/* Parse string second time to simplify */
	p = path;
	while(p<end) {
	    if (*p=='/') {
		if (p>*url && *(p+1)=='.' && (*(p+2)=='/' || !*(p+2))) {
		    char *orig = p+1;
		    char *dest = (*(p+2)!='/') ? p+2 : p+3;
		    while ((*orig++ = *dest++)); /* Remove a slash and a dot */
		    end = orig-1;
		} else if (*(p+1)=='.' && *(p+2)=='.' && (*(p+3)=='/' || !*(p+3))) {
		    char *q = p;
		    while (q>path && *--q!='/');	       /* prev slash */
		    if (strncmp(q, "/../", 4)) {
			char *orig = q+1;
			char *dest = (*(p+3)!='/') ? p+3 : p+4;
			while ((*orig++ = *dest++));	   /* Remove /xxx/.. */
			end = orig-1;
			p = q;		      /* Start again with prev slash */
		    } else
			p++;
		} else if (*(p+1)=='/') {
		    while (*(p+1)=='/') {
			char *orig=p, *dest=p+1;
			while ((*orig++ = *dest++));  /* Remove multiple /'s */
			end = orig-1;
		    }
		} else
		    p++;
	    } else
		p++;
	}
    }

    /*
    **  Check for host/../.. kind of things
    */
    if (*path=='/' && *(path+1)=='.' && *(path+2)=='.' && (!*(path+3) || *(path+3)=='/'))
	*(path+1) = '\0';
    if (URI_TRACE) HTTrace("into\n............ `%s'\n", *url);
    return *url;
}

/*		Make Relative Name
**		------------------
**
** This function creates and returns a string which gives an expression of
** one address as related to another. Where there is no relation, an absolute
** address is retured.
**
**  On entry,
**	Both names must be absolute, fully qualified names of nodes
**	(no fragment bits)
**
**  On exit,
**	The return result points to a newly allocated name which, if
**	parsed by HTParse relative to relatedName, will yield aName.
**	The caller is responsible for freeing the resulting name later.
**
*/
PUBLIC char * HTRelative (const char * aName, const char * relatedName)
{
    char * result = 0;
    const char *p = aName;
    const char *q = relatedName;
    const char * after_access = 0;
    const char * path = 0;
    const char * last_slash = 0;
    int slashes = 0;
    
    for(;*p; p++, q++) {	/* Find extent of match */
    	if (*p!=*q) break;
	if (*p==':') after_access = p+1;
	if (*p=='/') {
	    last_slash = p;
	    slashes++;
	    if (slashes==3) path=p;
	}
    }
    
    /* q, p point to the first non-matching character or zero */
    
    if (!after_access) {			/* Different access */
        StrAllocCopy(result, aName);
    } else if (slashes<3){			/* Different nodes */
    	StrAllocCopy(result, after_access);
    } else {					/* Some path in common */
        int levels= 0;
        for(; *q && *q!='#' && *q!=';' && *q!='?'; q++) if (*q=='/') levels++;
	if ((result = (char  *) HT_MALLOC(3*levels + strlen(last_slash) + 4)) == NULL)
	    HT_OUTOFMEM("HTRelative");
	*result = '\0';
	for(;levels; levels--)strcat(result, "../");
	strcat(result, last_slash+1);
	if (!*result) strcat(result, "./");
    }
    if (URI_TRACE)
	HTTrace("HTRelative.. `%s' expressed relative to `%s' is `%s'\n",
		aName, relatedName, result);
    return result;
}

/*							HTCleanTelnetString()
 *	Make sure that the given string doesn't contain characters that
 *	could cause security holes, such as newlines in ftp, gopher,
 *	news or telnet URLs; more specifically: allows everything between
 *	ASCII 20-7E, and also A0-FE, inclusive. Also TAB ('\t') allowed!
 *
 * On entry,
 *	str	the string that is *modified* if necessary.  The
 *		string will be truncated at the first illegal
 *		character that is encountered.
 * On exit,
 *	returns	YES, if the string was modified.
 *		NO, otherwise.
 */
PUBLIC BOOL HTCleanTelnetString (char * str)
{
    char * cur = str;

    if (!str) return NO;

    while (*cur) {
	int a = TOASCII((unsigned char) *cur);
	if (a != 0x9 && (a < 0x20 || (a > 0x7E && a < 0xA0) ||  a > 0xFE)) {
	    if (URI_TRACE)
		HTTrace("Illegal..... character in URL: \"%s\"\n",str);
	    *cur = 0;
	    if (URI_TRACE)
		HTTrace("Truncated... \"%s\"\n",str);
	    return YES;
	}
	cur++;
    }
    return NO;
}