/*
 *
 *  (c) COPYRIGHT MIT and INRIA, 1996-2001
 *  Please first read the full copyright statement in file COPYRIGHT.
 *
 */

/*
 * AHTURLTools.c: contains all the functions for testing, manipulating,
 * and normalizing URLs. It also contains a local copy of the libWWW
 * URL parsing functions.
 *
 * Authors: J. Kahan, I. Vatton
 *          R. Guetari: Windows.
 *
 */
 
#define THOT_EXPORT extern
#include "amaya.h"

#include "init_f.h"
#include "AHTURLTools_f.h"
#include "query_f.h"

#define MAX_PRINT_URL_LENGTH 50
typedef struct _HTURI
{
    char *access;		/* Now known as "scheme" */
    char *host;
    char *absolute;
    char *relative;
    char *fragment;
} HTURI;


/*----------------------------------------------------------------------
  ConvertToLowerCase
  Converts a string to lowercase.
  ----------------------------------------------------------------------*/
void         ConvertToLowerCase (char *string)
{
 int i;
 
 if (!string)
   return;

 for (i = 0; string[i] != EOS; i++)
   string[i] = utolower (string[i]);
}

/*----------------------------------------------------------------------
  EscapeChar
  writes the equivalent escape code of a char in a string
  ----------------------------------------------------------------------*/
void EscapeChar (char *string, char c)
{
  unsigned int i;

   i = (unsigned char) c & 0xFF;
   sprintf (string, "%02x", i);
}

/*----------------------------------------------------------------------
  UnEscapeChar
  writes the equivalent hex code to a %xx coded char
  ----------------------------------------------------------------------*/
static char UnEscapeChar (char c)
{
    return  c >= '0' && c <= '9' ?  c - '0'
            : c >= 'A' && c <= 'F' ? c - 'A' + 10
            : c - 'a' + 10;   /* accept small letters just in case */
}

/*----------------------------------------------------------------------
  EscapeURL
  Takes a URL and escapes all protected chars into
  %xx sequences. Also, removes any leading white spaces
  Returns either NULL or a new buffer, which must be freed by the caller
  ----------------------------------------------------------------------*/
char *EscapeURL (const char *url)
{
  char *buffer;
  int   buffer_len;
  int   buffer_free_mem;
  char *ptr;
  int   new_chars;
  void *status;

  if (url && *url)
    {
      buffer_free_mem = strlen (url) + 20;
      buffer = TtaGetMemory (buffer_free_mem + 1);
      ptr = (char *) url;
      buffer_len = 0;

      while (*ptr)
        {
          switch (*ptr)
            {
              /* put here below all the chars that need to
                 be escaped into %xx */
            case 0x27: /* &amp */
            case 0x20: /* space */
              new_chars = 3; 
              break;

            default:
              new_chars = 1; 
              break;
            }

          /* see if we need extra room in the buffer */
          if (new_chars > buffer_free_mem)
            {
              buffer_free_mem = 20;
              status = TtaRealloc (buffer, sizeof (char) 
				   * (buffer_len + buffer_free_mem + 1));
              if (status)
                buffer = (STRING) status;
              else
		{
		  /* @@ maybe we should do some other behavior here, like
		     freeing the buffer and return a void thing */
		  buffer[buffer_len] = EOS;
		  break;
		}
            }
	  /* escape the char */
          if (new_chars == 3)
            {
              buffer[buffer_len] = '%';
              EscapeChar (&buffer[buffer_len+1], *ptr);
            }
          else
            buffer[buffer_len] = *ptr;

          /* update the status */
          buffer_len += new_chars;
          buffer_free_mem -= new_chars;
          /* examine the next char */
          ptr++;
        }
      buffer[buffer_len] = EOS;
    }
  else
    buffer = NULL;

  return (buffer);
}


/*----------------------------------------------------------------------
  ExplodeURL 
  ----------------------------------------------------------------------*/
void ExplodeURL (char *url, char **proto, char **host, char **dir,
		 char **file)
{
   char            *curr, *temp;
   char             used_sep;

   if (url && strchr (url, URL_SEP))
     used_sep = URL_SEP;
   else
     used_sep = DIR_SEP;

   if ((url == NULL) || (proto == NULL) || (host == NULL) ||
       (dir == NULL) || (file == NULL))
      return;

   /* initialize every pointer */
   *proto = *host = *dir = *file = NULL;

   /* skip any leading space */
   while ((*url == SPACE) || (*url == TAB))
      url++;
   curr = url;
   if (*curr == 0)
      goto finished;

   /* go to the end of the URL */
   while ((*curr != EOS) && (*curr != SPACE) && (*curr != BSPACE) &&
	  (*curr != __CR__) && (*curr != EOL))
      curr++;

   /* mark the end of the chain */
   *curr = EOS;
   curr--;
   if (curr <= url)
      goto finished;

   /* search the next DIR_SEP indicating the beginning of the file name */
   do
     curr--;
   while ((curr >= url) && (*curr != used_sep));

   if (curr < url)
      goto finished;
   *file = curr + 1;

   /* mark the end of the dir */
   *curr = EOS;
   curr--;
   if (curr < url)
      goto finished;

   /* search for the DIR_STR indicating the host name start */
   while ((curr > url) && ((*curr != used_sep) || (*(curr + 1) != used_sep)))
      curr--;

   /* if we found it, separate the host name from the directory */
   if ((*curr == used_sep) && (*(curr + 1) == used_sep))
     {
	*host = temp = curr + 2;
	while ((*temp != 0) && (*temp != used_sep))
	   temp++;
	if (*temp == used_sep)
	  {
	     *temp = EOS;
	     *dir = temp + 1;
	  }
     }
   else
     *dir = curr;

   if (curr <= url)
      goto finished;

   /* mark the end of the proto */
   *curr = EOS;
   curr--;
   if (curr < url)
      goto finished;

   if (*curr == ':')
     {
	*curr = EOS;
	curr--;
     }
   else
      goto finished;

   if (curr < url)
      goto finished;
   while ((curr > url) && (isalpha (*curr)))
      curr--;
   *proto = curr;

 finished:;

#ifdef AMAYA_DEBUG
   fprintf (stderr, "ExplodeURL(%s)\n\t", url);
   if (*proto)
      fprintf (stderr, "proto : %s, ", *proto);
   if (*host)
      fprintf (stderr, "host : %s, ", *host);
   if (*dir)
      fprintf (stderr, "dir : %s, ", *dir);
   if (*file)
      fprintf (stderr, "file : %s ", *file);
   fprintf (stderr, "\n");
#endif

}


/*----------------------------------------------------------------------
   ExtractSuffix extract suffix from document nane.                
  ----------------------------------------------------------------------*/
void ExtractSuffix (char *aName, char *aSuffix)
{
   int               lg, i;
   char             *ptr, *oldptr;

   if (!aSuffix || !aName)
     /* bad suffix */
     return;

   aSuffix[0] = EOS;
   lg = strlen (aName);
   if (lg)
     {
	/* the name is not empty */
	oldptr = ptr = &aName[0];
	do
	  {
	     ptr = strrchr (oldptr, '.');
	     if (ptr)
		oldptr = &ptr[1];
	  }
	while (ptr);

	i = (int) (oldptr) - (int) (aName);	/* name length */
	if (i > 1)
	  {
	     aName[i - 1] = EOS;
	     if (i != lg)
		strcpy (aSuffix, oldptr);
	  }
     }
}

/*----------------------------------------------------------------------
  IsHTMLName                                                         
  returns TRUE if path points to an HTML resource.
  ----------------------------------------------------------------------*/
ThotBool IsHTMLName (const char *path)
{
  char              temppath[MAX_LENGTH];
  char              suffix[MAX_LENGTH];
  char              nsuffix[MAX_LENGTH];
  int               i; 

  if (!path)
    return (FALSE);

  strcpy (temppath, path);
  ExtractSuffix (temppath, suffix);
  i = 0;
  while (suffix[i] != EOS)
    {
      /* Normalize the suffix */
      i = 0;
      while (suffix[i] != EOS && i < MAX_LENGTH -1)
	{
	  nsuffix[i] = utolower (suffix[i]);
	  i++;
	}
      nsuffix[i] = EOS;
      if (!strcmp (nsuffix, "html") ||
	  !strcmp (nsuffix, "htm") ||
	  !strcmp (nsuffix, "shtml") ||
	  !strcmp (nsuffix, "jsp") ||
	  !strcmp (nsuffix, "xht") ||
	  !strcmp (nsuffix, "xhtm") ||
	  !strcmp (nsuffix, "xhtml"))
	return (TRUE);
      else if (!strcmp (nsuffix, "gz"))
	{
	  /* take into account compressed files */
	  ExtractSuffix (temppath, suffix);       
	  /* Normalize the suffix */
	  i = 0;
	  while (suffix[i] != EOS && i < MAX_LENGTH -1)
	    {
	      nsuffix[i] = utolower (suffix[i]);
	      i++;
	    }
	  nsuffix[i] = EOS;
	  if (!strcmp (nsuffix, "html") ||
	      !strcmp (nsuffix, "htm") ||
	      !strcmp (nsuffix, "shtml") ||
	      !strcmp (nsuffix, "jsp") ||
	      !strcmp (nsuffix, "xht") ||
	      !strcmp (nsuffix, "xhtm") ||
	      !strcmp (nsuffix, "xhtml"))
	    return (TRUE);
	  else
	    return (FALSE);
	}
      else
	/* check if there is another suffix */
	ExtractSuffix (temppath, suffix);
    }
   return (FALSE);
}

/*----------------------------------------------------------------------
  IsXMLName                                                         
  returns TRUE if path points to an XML resource.
  ----------------------------------------------------------------------*/
ThotBool             IsXMLName (const char *path)
{
   char                temppath[MAX_LENGTH];
   char                suffix[MAX_LENGTH];

   if (!path)
      return (FALSE);

   strcpy (temppath, path);
   ExtractSuffix (temppath, suffix);

   if (!strcasecmp (suffix, "xml") ||
       !strcasecmp (suffix, "xht") ||
       !strcmp (suffix, "xhtm") ||
       !strcmp (suffix, "xhtml"))
     return (TRUE);
   else if (!strcmp (suffix, "gz"))
     {
       /* take into account compressed files */
       ExtractSuffix (temppath, suffix);       
       if (!strcasecmp (suffix, "xml") ||
	   !strcasecmp (suffix, "xht") ||
	   !strcmp (suffix, "xhtm") ||
	   !strcmp (suffix, "xhtml"))
	 return (TRUE);
       else
	 return (FALSE);
     }
   else
     return (FALSE);
}

/*----------------------------------------------------------------------
  IsMathMLName                                                         
  returns TRUE if path points to an MathML resource.
  ----------------------------------------------------------------------*/
ThotBool             IsMathMLName (const char *path)
{
   char                temppath[MAX_LENGTH];
   char                suffix[MAX_LENGTH];

   if (!path)
      return (FALSE);

   strcpy (temppath, path);
   ExtractSuffix (temppath, suffix);

   if (!strcasecmp (suffix, "mml"))
     return (TRUE);
   else if (!strcmp (suffix, "gz"))
     {
       /* take into account compressed files */
       ExtractSuffix (temppath, suffix);       
       if (!strcasecmp (suffix, "mml"))
	 return (TRUE);
       else
	 return (FALSE);
     }
   else
     return (FALSE);
}

/*----------------------------------------------------------------------
  IsSVGName                                                         
  returns TRUE if path points to an MathML resource.
  ----------------------------------------------------------------------*/
ThotBool             IsSVGName (const char *path)
{
   char                temppath[MAX_LENGTH];
   char                suffix[MAX_LENGTH];

   if (!path)
      return (FALSE);

   strcpy (temppath, path);
   ExtractSuffix (temppath, suffix);

   if (!strcasecmp (suffix, "svg"))
     return (TRUE);
   else if (!strcmp (suffix, "gz"))
     {
       /* take into account compressed files */
       ExtractSuffix (temppath, suffix);       
       if (!strcasecmp (suffix, "svg"))
	 return (TRUE);
       else
	 return (FALSE);
     }
   else
     return (FALSE);
}

/*----------------------------------------------------------------------
  IsCSSName                                                         
  returns TRUE if path points to an XML resource.
  ----------------------------------------------------------------------*/
ThotBool             IsCSSName (const char *path)
{
   char                temppath[MAX_LENGTH];
   char                suffix[MAX_LENGTH];

   if (!path)
      return (FALSE);

   strcpy (temppath, path);
   ExtractSuffix (temppath, suffix);

   if (!strcasecmp (suffix, "css"))
     return (TRUE);
   else if (!strcmp (suffix, "gz"))
     {
       /* take into account compressed files */
       ExtractSuffix (temppath, suffix);       
       if (!strcasecmp (suffix, "css"))
	 return (TRUE);
       else
	 return (FALSE);
     }
   else
     return (FALSE);
}

/*----------------------------------------------------------------------
  IsImageName                                
  returns TRUE if path points to an image resource.
  ----------------------------------------------------------------------*/
ThotBool             IsImageName (const char *path)
{
   char                temppath[MAX_LENGTH];
   char                suffix[MAX_LENGTH];
   char                nsuffix[MAX_LENGTH];
   int                 i;

   if (!path)
      return (FALSE);

   strcpy (temppath, path);
   ExtractSuffix (temppath, suffix);

   /* Normalize the suffix */
   i = 0;
   while (suffix[i] != EOS && i < MAX_LENGTH -1)
     {
       nsuffix[i] = utolower (suffix[i]);
       i++;
     }
   nsuffix[i] = EOS;
   if ((!strcmp (nsuffix, "gif")) || (!strcmp (nsuffix, "xbm")) ||
       (!strcmp (nsuffix, "xpm")) || (!strcmp (nsuffix, "jpg")) ||
       (!strcmp (nsuffix, "png")) || (!strcmp (nsuffix, "au")))
      return (TRUE);
   return (FALSE);
}

/*----------------------------------------------------------------------
  IsImageType                                
  returns TRUE if type points to an image resource.
  ----------------------------------------------------------------------*/
ThotBool             IsImageType (const char *type)
{
   char                temptype[MAX_LENGTH];
   int                 i;

   if (!type)
      return (FALSE);

   strcpy (temptype, type);
   /* Normalize the type */
   i = 0;
   while (temptype[i] != EOS)
     {
       temptype[i] = tolower (temptype[i]);
       i++;
     }
   if ((!strcmp (temptype, "gif")) || (!strcmp (temptype, "x-xbitmap")) ||
       (!strcmp (temptype, "x-xpixmap")) || (!strcmp (temptype, "jpeg")) ||
       (!strcmp (temptype, "png")))
      return (TRUE);
   return (FALSE);
}

/*----------------------------------------------------------------------
  IsTextName                                                         
  ----------------------------------------------------------------------*/
ThotBool             IsTextName (const char *path)
{
   char                temppath[MAX_LENGTH];
   char                suffix[MAX_LENGTH];
   char                nsuffix[MAX_LENGTH];
   int                 i;

   if (!path)
     return (FALSE);

   strcpy (temppath, path);
   ExtractSuffix (temppath, suffix);

   /* Normalize the suffix */
   i = 0;
   while (suffix[i] != EOS && i < MAX_LENGTH -1)
     {
	nsuffix[i] = tolower (suffix[i]);
	i++;
     }
   nsuffix[i] = EOS;

   if ((!strcmp (nsuffix, "txt")) || (!strcmp (nsuffix, "dtd")))
      return (TRUE);
   else if (!strcmp (nsuffix, "gz"))
     {
       /* take into account compressed files */
       ExtractSuffix (temppath, suffix);       
       /* Normalize the suffix */
       i = 0;
       while (suffix[i] != EOS && i < MAX_LENGTH -1)
	 {
	   nsuffix[i] = tolower (suffix[i]);
	   i++;
	 }
       nsuffix[i] = EOS;
       if ((!strcmp (nsuffix, "txt")) || (!strcmp (nsuffix, "dtd")))
	 return (TRUE);
       else
	 return (FALSE);
     }
   else
     return (FALSE);
}

/*----------------------------------------------------------------------
  IsHTTPPath                                     
  returns TRUE if path is in fact an http URL.
  ----------------------------------------------------------------------*/
ThotBool             IsHTTPPath (const char *path)
{
   if (!path)
      return FALSE;

   if ((!strncmp (path, "http:", 5) != 0)
       || (AHTFTPURL_flag () && !strncmp (path, "ftp:", 4))
       || !strncmp (path, "internal:", 9))
      return TRUE;
   return FALSE;
}

/*----------------------------------------------------------------------
  IsWithParameters                           
  returns TRUE if url has a concatenated query string.
  ----------------------------------------------------------------------*/
ThotBool            IsWithParameters (const char *url)
{
   int                 i;

   if ((!url) || (url[0] == EOS))
      return FALSE;

   i = strlen (url) - 1;
   while (i > 0 && url[i--] != '?')
      if (i < 0)
	 return FALSE;

   /* There is a parameter */
   return TRUE;
}

/*----------------------------------------------------------------------
  IsW3Path                                           
  returns TRUE if path is in fact a URL.
  ----------------------------------------------------------------------*/
ThotBool             IsW3Path (const char *path)
{
  if (strncmp (path, "http:", 5)   && 
      strncmp (path, "ftp:", 4)    &&
      strncmp (path, "telnet:", 7) && 
      strncmp (path, "wais:", 5)   &&
      strncmp (path, "news:", 5)   && 
      strncmp (path, "gopher:", 7) &&
      strncmp (path, "mailto:", 7) && 
      strncmp (path, "archie:", 7))
    return FALSE;
  return TRUE;
}

/*----------------------------------------------------------------------
  IsFilePath                                           
  returns TRUE if path is in fact a URL.
  ----------------------------------------------------------------------*/
ThotBool             IsFilePath (const char *path)
{
  if (strncmp (path, "file:", 5))
    return FALSE;
  return TRUE;
}

/*----------------------------------------------------------------------
  IsValidProtocol                                                    
  returns true if the url protocol is supported by Amaya.
  ----------------------------------------------------------------------*/
ThotBool             IsValidProtocol (const char *url)
{
   if (!strncmp (url, "http:", 5)
      || !strncmp (url, "internal:", 9)
      || (AHTFTPURL_flag () && !strncmp (url, "ftp:", 4)))
       /* experimental */
     /*** || !strncmp (path, "news:", 5)***/ 
      return (TRUE);
   else
      return (FALSE);
}


/*----------------------------------------------------------------------
   GetBaseURL
   normalizes orgName according to a base associated with doc, and
   following the standard URL format rules.
   The function returns the base used to solve relative URL and SRC:
      - the base of the document,
      - or the document path (without document name).
  ----------------------------------------------------------------------*/
char  *GetBaseURL (Document doc)
{
  Element             el;
  ElementType         elType;
  AttributeType       attrType;
  Attribute           attr;
  char               *ptr, *basename;
  int                 length;

  /* @@@ irene */
  if (!DocumentURLs[doc])
     return NULL;
  basename = TtaGetMemory (MAX_LENGTH);
  strncpy (basename, DocumentURLs[doc], MAX_LENGTH-1);
  basename[MAX_LENGTH-1] = EOS;
  length = MAX_LENGTH -1;
  /* get the document element */
  el = TtaGetMainRoot (doc);
  /* search the BASE element */
  elType.ElSSchema = TtaGetDocumentSSchema (doc);
  elType.ElTypeNum = HTML_EL_HEAD;
  el = TtaSearchTypedElement (elType, SearchForward, el);
  if (el)
    {
      elType.ElTypeNum = HTML_EL_BASE;
      el = TtaSearchTypedElement (elType, SearchInTree, el);
    }
  if (el)
    {
      /*  The document has a BASE element -> Get the HREF attribute */
      attrType.AttrSSchema = elType.ElSSchema;
      attrType.AttrTypeNum = HTML_ATTR_HREF_;
      attr = TtaGetAttribute (el, attrType);
      if (attr)
	{
	  /* Use the base path of the document */
	  TtaGiveTextAttributeValue (attr, basename, &length);
	  /* base and orgName have to be separated by a DIR_SEP */
	  length--;
	  if (basename[0] != EOS && basename[length] != URL_SEP &&
	      basename[length] != DIR_SEP) 
	    /* verify if the base has the form "protocol://server:port" */
	    {
	      ptr = AmayaParseUrl (basename, "", AMAYA_PARSE_ACCESS |
				                 AMAYA_PARSE_HOST |
				                 AMAYA_PARSE_PUNCTUATION);
	      if (ptr && !strcmp (ptr, basename))
		{
		  /* it has this form, we complete it by adding a URL_STR  */
		  if (strchr (basename, DIR_SEP))
		    strcat (basename, DIR_STR);
		  else
		    strcat (basename, URL_STR);
		  length++;
		}
	      if (ptr)
		TtaFreeMemory (ptr);
	    }
	}
      }
  
  /* Remove anything after the last DIR_SEP char. If no such char is found,
   * then search for the first ":" char, hoping that what's before that is a
   * protocol. If found, end the string there. If neither char is found,
   * then discard the whole base element.
   */
  length = strlen (basename) - 1;
  /* search for the last DIR_SEP char */
  while (length >= 0  && basename[length] != URL_SEP && basename[length] != DIR_SEP)
    length--;
  if (length >= 0)
    /* found the last DIR_SEP char, end the string there */
    basename[length + 1] = EOS;		   
  else
    /* search for the first PATH_STR char */
    {
      for (length = 0; basename[length] != ':' && 
	     basename[length] != EOS; length ++);
      if (basename[length] == ':')
	/* found, so end the string there */
	basename[length + 1] = EOS;
      else
	/* not found, discard the base */
	basename[0] = EOS;
    }
  return (basename);
}


/*----------------------------------------------------------------------
   GetLocalPath
   Allocate and return the local document path associated to the url
  ----------------------------------------------------------------------*/
char  *GetLocalPath (Document doc, char  *url)
{
  char     *ptr;
  char     *n;
  char     *documentname;
  char      url_sep;
  int       len;
  ThotBool  noFile;

  if (url != NULL)
    {
      /* check whether the file name exists */
      len = strlen (url) - 1;
      if (IsW3Path (url))
         url_sep = '/';
      else 
          url_sep = DIR_SEP;
      noFile = (url[len] == url_sep);
      if (noFile)
         url[len] = EOS;
      ptr = TtaGetMemory (MAX_LENGTH);
      documentname = TtaGetMemory (MAX_LENGTH);
      TtaExtractName (url, ptr, documentname);
      sprintf (ptr, "%s%s%d%s", TempFileDirectory, DIR_STR, doc, DIR_STR);
      if (!TtaCheckDirectory (ptr))
	/* directory did not exist */
	TtaMakeDirectory (ptr);

      /* don't include the query string within document name */
      n = strrchr (documentname, '?');
      if (n != NULL)
         *n = EOS;
      /* don't include ':' within document name */
      n = strchr (documentname, ':');
      if (n != NULL)
         *n = EOS;
      /* if after all this operations document name
	 is empty, let's use noname.html instead */
      if (documentname[0] == EOS)
         strcat (ptr, "noname.html");
      else
          strcat (ptr, documentname);
      TtaFreeMemory (documentname);
      /* restore the url */
      if (noFile)
	url[len] = url_sep;
      return (ptr);
    }
  else
    return (NULL);
}

/*----------------------------------------------------------------------
   ExtractTarget extract the target name from document nane.        
  ----------------------------------------------------------------------*/
void         ExtractTarget (char *aName, char *target)
{
   int    lg, i;
   char  *ptr;
   char  *oldptr;

   if (!target || !aName)
     /* bad target */
     return;

   target[0] = EOS;
   lg = strlen (aName);
   if (lg)
     {
	/* the name is not empty */
	oldptr = ptr = &aName[0];
	do
	  {
	     ptr = strrchr (oldptr, '#');
	     if (ptr)
		oldptr = &ptr[1];
	  }
	while (ptr);

	i = (int) (oldptr) - (int) (aName);	/* name length */
	if (i > 1)
	  {
	     aName[i - 1] = EOS;
	     if (i != lg)
		strcpy (target, oldptr);
	  }
     }
}

/*----------------------------------------------------------------------
   RemoveNewLines (text)
   Removes any '\n' chars that are found in text. 
   Returns TRUE if it did the operation, FALSE otherwise.
  ----------------------------------------------------------------------*/
ThotBool RemoveNewLines (char *text)
{
  ThotBool   change = FALSE;
  char      *src;
  char      *dest;

  src = text;
  dest = text;
  while (*src)
    {
      switch (*src)
	{
	case '\n':
	  /* don't copy the newline */
	  change = 1;
	  break;
	default:
	  *dest = *src;
	  dest++;
	  break;
	}
      src++;
    }
  /* copy the last EOS char */
  *dest = *src;

  return (change);
}

/*----------------------------------------------------------------------
   CleanCopyFileURL
   Copies a file url from a src string to destination string.
   convertion says which type of convertion (none, %xx, URL_SEP into DIR_SEP
   we want to do).
  ----------------------------------------------------------------------*/
static void CleanCopyFileURL (char *dest, char *src,
			      ConvertionType convertion)
{
  while (*src)
    {
      switch (*src)
	{
#ifdef _WINDOWS
	case URL_SEP:
	  /* make DIR_SEP transformation */
	  if (convertion & AM_CONV_URL_SEP)
	    *dest = DIR_SEP;
	  else
	    *dest = *src;
	  dest++;
	  src++;
	  break;
#endif /* _WINDOWS */

	case '%':
	  if (convertion & AM_CONV_PERCENT)
	    {
	      /* (code adapted from libwww's HTUnEscape function */
	      src++;
	      if (*src != EOS)
		{
		  *dest = UnEscapeChar (*src) * 16;
		  src++;
		}
	      if (*src != EOS)
		{
		  *dest = *dest + UnEscapeChar (*src);
		  src++;
		}
	      dest++;
	    }
	  else
	    {
	      *dest = *src;
	      dest++;
	      src++;
	    }
	  break;

	default:
	  *dest = *src;
	  dest++;
	  src++;
	  break;
	}
    }
  /* copy the EOS char */
  *dest = *src;
}

/*----------------------------------------------------------------------
   NormalizeURL
   normalizes orgName according to a base associated with doc, and
   following the standard URL format rules.
   if doc is 0 and otherPath not NULL, normalizes orgName according to this
   other path.
   The function returns the new complete and normalized URL 
   or file name path (newName) and the name of the document (docName).        
   N.B. If the function can't find out what's the docName, it assigns
   the name "noname.html".
  ----------------------------------------------------------------------*/
void NormalizeURL (char *orgName, Document doc, char *newName,
		   char *docName, char *otherPath)
{
   char          *basename;
   char           tempOrgName[MAX_LENGTH];
   char          *ptr;
   char           used_sep;
   int            length;
   ThotBool       check;

#ifdef _WINDOWS
   int ndx;
#endif /* _WINDOWS */

   if (!newName || !docName)
      return;

   if (doc != 0)
     basename = GetBaseURL (doc);
   else if (otherPath != NULL)
     basename = TtaStrdup (otherPath);
   else
     basename = NULL;

   /*
    * Clean orgName
    * Make sure we have a complete orgName, without any leading or trailing
    * white spaces, or trailinbg new lines
    */
   ptr = orgName;
   /* skip leading white space and new line characters */
   while ((*ptr == SPACE || *ptr == EOL) && *ptr++ != EOS);
   strncpy (tempOrgName, ptr, MAX_LENGTH -1);
   tempOrgName[MAX_LENGTH -1] = EOS;
   /*
    * Make orgName a complete URL
    * If the URL does not include a protocol, then try to calculate
    * one using the doc's base element (if it exists),
    */
   if (tempOrgName[0] == EOS)
     {
       newName[0] = EOS;
       docName[0] = EOS;
       TtaFreeMemory (basename);
       return;
     }

   /* clean trailing white space */
   length = strlen (tempOrgName) - 1;
   while (tempOrgName[length] == SPACE && tempOrgName[length] == EOL)
     {
       tempOrgName[length] = EOS;
       length--;
     }

   /* remove extra dot (which dot???) */
   /* ugly, but faster than a strcmp */
   if (tempOrgName[length] == '.'
       && (length == 0 || tempOrgName[length-1] != '.'))
	 tempOrgName[length] = EOS;

   if (IsW3Path (tempOrgName))
     {
       /* the name is complete, go to the Sixth Step */
       strcpy (newName, tempOrgName);
       SimplifyUrl (&newName);
       /* verify if the URL has the form "protocol://server:port" */
       ptr = AmayaParseUrl (newName, "", AMAYA_PARSE_ACCESS |
			                 AMAYA_PARSE_HOST |
			                 AMAYA_PARSE_PUNCTUATION);
       if (ptr && !strcmp (ptr, newName))
	 /* it has this form, we complete it by adding a DIR_STR  */
         strcat (newName, URL_STR);

       if (ptr)
         TtaFreeMemory (ptr);
     }
   else if ( basename == NULL)
     /* the name is complete, go to the Sixth Step */
     strcpy (newName, tempOrgName);
   else
     {
       /* Calculate the absolute URL, using the base or document URL */
#ifdef _WINDOWS
       if (!IsW3Path (basename))
	 {
	   length = strlen (tempOrgName);
	   for (ndx = 0; ndx < length; ndx++)
	     if (tempOrgName [ndx] == '/')
	       tempOrgName [ndx] = '\\';
	 }
#endif /* _WINDOWS */
       ptr = AmayaParseUrl (tempOrgName, basename, AMAYA_PARSE_ALL);
       if (ptr)
	 {
	   SimplifyUrl (&ptr);
	   strcpy (newName, ptr);
	   TtaFreeMemory (ptr);
	 }
       else
	 newName[0] = EOS;
     }

   TtaFreeMemory (basename);
   /*
    * Prepare the docname that will refer to this ressource in the
    * .amaya directory. If the new URL finishes on DIR_SEP, then use
    * noname.html as a default ressource name
   */
   if (newName[0] != EOS)
     {
       length = strlen (newName) - 1;
       if (newName[length] == URL_SEP || newName[length] == DIR_SEP)
	 {
	   used_sep = newName[length];
	   check = TRUE;
	   while (check)
	     {
               length--;
               while (length >= 0 && newName[length] != used_sep)
		 length--;
               if (!strncmp (&newName[length+1], "..", 2))
		 {
		   newName[length+1] = EOS;
		   /* remove also previous directory */
		   length--;
		   while (length >= 0 && newName[length] != used_sep)
		     length--;
		   if (strncmp (&newName[length+1], "//", 2))
		     /* don't remove server name */
                     newName[length+1] = EOS;
		 }
	       else if (!strncmp (&newName[length+1], ".", 1))
		 newName[length+1] = EOS;
               else
		 check = FALSE;
	     }
	   strcpy (docName, "noname.html");	       
	   /* docname was not comprised inside the URL, so let's */
	   /* assign the default ressource name */
	   strcpy (docName, "noname.html");
	 }
       else
	 { /* docname is comprised inside the URL */
           while (length >= 0 && newName[length] != URL_SEP &&
		  newName[length] != DIR_SEP)
	     length--;
	   if (length < 0)
             strcpy (docName, newName);
	   else
	     strcpy (docName, &newName[length+1]);
	 }
     }
   else
     docName[0] = EOS;
} 

/*----------------------------------------------------------------------
  IsSameHost                                                         
  ----------------------------------------------------------------------*/
ThotBool IsSameHost (const char *url1, const char *url2)
{
  char          *basename_ptr1, *basename_ptr2;
  ThotBool       result;

  basename_ptr1 = AmayaParseUrl (url1, "",
	     AMAYA_PARSE_ACCESS | AMAYA_PARSE_HOST | AMAYA_PARSE_PUNCTUATION);
  basename_ptr2 = AmayaParseUrl (url2, "",
	     AMAYA_PARSE_ACCESS | AMAYA_PARSE_HOST | AMAYA_PARSE_PUNCTUATION);

  if (strcmp (basename_ptr1, basename_ptr2))
    result = FALSE;
  else
    result = TRUE;
  TtaFreeMemory (basename_ptr1);
  TtaFreeMemory (basename_ptr2);
  return (result);
}


/*----------------------------------------------------------------------
  HasKnownFileSuffix
  returns TRUE if path points to a file ending with a suffix.
  ----------------------------------------------------------------------*/
ThotBool             HasKnownFileSuffix (const char *path)
{
   char       *root;
   char        temppath[MAX_LENGTH];
   char        suffix[MAX_LENGTH];

   if (!path || path[0] == EOS || path[strlen(path)] == DIR_SEP)
     return (FALSE);

   root = AmayaParseUrl(path, "", AMAYA_PARSE_PATH | AMAYA_PARSE_PUNCTUATION);

   if (root) 
     {
       strcpy (temppath, root);
       TtaFreeMemory (root);
       /* Get the suffix */
       ExtractSuffix (temppath, suffix); 

       if( suffix[0] == EOS)
	 /* no suffix */
	 return (FALSE);

       /* Normalize the suffix */
       ConvertToLowerCase (suffix);

       if (!strcmp (suffix, "gz"))
	 /* skip the compressed suffix */
	 {
	 ExtractSuffix (temppath, suffix);
	 if(suffix[0] == EOS)
	   /* no suffix */
	   return (FALSE);
         /* Normalize the suffix */
         ConvertToLowerCase (suffix);
	 }

       if (strcmp (suffix, "gif") &&
	   strcmp (suffix, "xbm") &&
	   strcmp (suffix, "xpm") &&
	   strcmp (suffix, "jpg") &&
	   strcmp (suffix, "pdf") &&
	   strcmp (suffix, "png") &&
	   strcmp (suffix, "tgz") &&
	   strcmp (suffix, "xpg") &&
	   strcmp (suffix, "xpd") &&
	   strcmp (suffix, "ps") &&
	   strcmp (suffix, "au") &&
	   strcmp (suffix, "html") &&
	   strcmp (suffix, "htm") &&
	   strcmp (suffix, "shtml") &&
	   strcmp (suffix, "xht") &&
	   strcmp (suffix, "xhtm") &&
	   strcmp (suffix, "xhtml") &&
	   strcmp (suffix, "txt") &&
	   strcmp (suffix, "css") &&
	   strcmp (suffix, "eps"))
	 return (FALSE);
       else
	 return (TRUE);
     }
   else
     return (FALSE);
}


/*----------------------------------------------------------------------
  ChopURL
  Gives back a URL no longer than MAX_PRINT_URL_LENGTH chars (outputURL). 
  If inputURL is  bigger than that size, outputURL receives
  MAX_PRINT_URL_LENGTH / 2 chars from the beginning of inputURL, "...", 
  and MAX_PRINT_URL_LENGTH / 2 chars from the end of inputURL.
  If inputURL is not longer than MAX_PRINT_URL_LENGTH chars, it gets
  copied into outputURL. 
  N.B.: outputURL must point to a memory block of MAX_PRINT_URL_LENGTH
  chars.
  ----------------------------------------------------------------------*/
void ChopURL (char *outputURL, const char *inputURL)
{
  int len;

  len = strlen (inputURL);
  if (len <= MAX_PRINT_URL_LENGTH) 
    strcpy (outputURL, inputURL);
  else
    /* make a truncated urlName on the status window */
    {
      strncpy (outputURL, inputURL, MAX_PRINT_URL_LENGTH / 2);
      outputURL [MAX_PRINT_URL_LENGTH / 2] = EOS;
      strcat (outputURL, "...");
      strcat (outputURL, &(inputURL[len - MAX_PRINT_URL_LENGTH / 2 ]));
    }
}


/*----------------------------------------------------------------------
   scan
  	Scan a filename for its constituents
  	-----------------------------------
  
   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.
  ----------------------------------------------------------------------*/
static void scan (char *name, HTURI *parts)
{
  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;
    }
    
  for (p=name; *p; p++)
    {
      if (*p == URL_SEP || *p == DIR_SEP || *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 (!strcasecmp("URL", parts->access))
	    /* Ignore IETF's URL: pre-prefix */
	    parts->access = NULL;
	  else
	    break;
	}
    }
    
    p = after_access;
    if (*p == URL_SEP || *p == DIR_SEP)
      {
	if (p[1] == URL_SEP)
	  {
	    parts->host = p+2;		/* host has been specified 	*/
	    *p = 0;			/* Terminate access 		*/
	    /* look for end of host name if any */
	    p = strchr (parts->host, URL_SEP);
	    if (p)
	      {
	        *p = EOS;			/* Terminate host */
	        parts->absolute = p+1;		/* Root has been found */
	      }
	  }
	else
	  /* Root found but no host */
	  parts->absolute = p+1;
      }
    else
      {
        parts->relative = (*after_access) ? after_access : 0; /* zero for "" */
      }
}


/*----------------------------------------------------------------------
  AmayaParseUrl: 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
  ----------------------------------------------------------------------*/
char   *AmayaParseUrl (const char *aName, char *relatedName, int wanted)
{
  char      *return_value;
  char       result[MAX_LENGTH];
  char       name[MAX_LENGTH];
  char       rel[MAX_LENGTH];
  char      *p, *access;
  HTURI      given, related;
  int        len;
  char       used_sep;
  char      *used_str;

  if (strchr (aName, DIR_SEP) || strchr (relatedName, DIR_SEP))
    {
      used_str = DIR_STR;
      used_sep = DIR_SEP;
    }
  else
    {
      used_str = URL_STR;
      used_sep = URL_SEP;
    }

  /* Make working copies of input strings to cut up: */
  return_value = NULL;
  result[0] = 0;		/* Clear string  */
  strcpy (name, aName);
  if (relatedName != NULL)  
    strcpy (rel, relatedName);
  else
    relatedName[0] = EOS;
  
  scan (name, &given);
  scan (rel,  &related); 
  access = given.access ? given.access : related.access;
  if (wanted & AMAYA_PARSE_ACCESS)
    if (access)
      {
	strcat (result, access);
	if(wanted & AMAYA_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 & AMAYA_PARSE_HOST)
    if(given.host || related.host)
      {
	if(wanted & AMAYA_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 & AMAYA_PARSE_PATH)
    {
      if (given.absolute)
	{
	  /* All is given */
	  if (wanted & AMAYA_PARSE_PUNCTUATION)
	    strcat (result, used_str);
	  strcat (result, given.absolute);
	}
      else if (related.absolute)
	{
	  /* Adopt path not name */
	  strcat (result, used_str);
	  strcat (result, related.absolute);
	  if (given.relative)
	    {
	      /* Search part? */
	      p = strchr (result, '?');
	      if (!p)
		p=result+strlen(result)-1;
	      for (; *p!=used_sep; p--);	/* last / */
	      /* Remove filename */
	      p[1]=0;
	      /* Add given one */
	      strcat (result, given.relative);
	    }
	}
      else if (given.relative)
	/* what we've got */
	strcat (result, given.relative);
      else if (related.relative)
	strcat (result, related.relative);
      else
	/* No inheritance */
	strcat (result, used_str);
    }
  
  if (wanted & AMAYA_PARSE_ANCHOR)
    if (given.fragment || related.fragment)
      {
	if (given.absolute && given.fragment)
	  {
	    /*Fixes for relURLs...*/
	    if (wanted & AMAYA_PARSE_PUNCTUATION)
	      strcat (result, "#");
	    strcat (result, given.fragment); 
	  }
	else if (!(given.absolute) && !(given.fragment))
	  strcat (result, "");
	else
	  {
	   if (wanted & AMAYA_PARSE_PUNCTUATION)
	      strcat (result, "#");
	   strcat (result, given.fragment ? given.fragment : related.fragment); 
	  }
      }
  len = strlen (result);
  if ((return_value = TtaGetMemory (len + 1)) != NULL)
    strcpy (return_value, result);
  return (return_value);		/* exactly the right length */
}

/*----------------------------------------------------------------------
     HTCanon
  	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.
  
  ----------------------------------------------------------------------*/
static char   *HTCanon (char **filename, char *host)
{
    char   *newname = NULL;
    char    used_sep;
    char   *path;
    char   *strptr;
    char   *port;
    char   *access = host-3;
  
     if (*filename && strchr (*filename, URL_SEP))
	 used_sep = URL_SEP;
     else
	 used_sep = DIR_SEP;
  
    while (access > *filename && *(access - 1) != used_sep) /* Find access method */
	access--;
    if ((path = strchr (host, used_sep)) == 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 = utolower (*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. */
    {
      char  *dot = port ? port : path;
      if (dot > *filename && *--dot == '.')
	{
	  char  *orig = dot;
	  char  *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) == used_sep)
	  {
	    if (!newname)
	      {
		char  *orig = port; 
		char  *dest = port + 1;
		while ((*orig++ = *dest++));
	      }
	  }
	else if ((!strncmp (access, "http", 4)   &&
             (*(port + 1) == '8'                    && 
             *(port+2) == '0'                       && 
             (*(port+3) == used_sep || !*(port + 3))))       ||
             (!strncmp (access, "gopher", 6) &&
             (*(port+1) == '7'                      && 
             *(port+2) == '0'                       && 
             (*(port+3) == used_sep || !*(port+3))))         ||
             (!strncmp (access, "ftp", 3)    &&
             (*(port+1) == '2'                      && 
             *(port + 2) == '1'                     && 
             (*(port+3) == used_sep || !*(port+3))))) {
	  if (!newname)
	    {
	      char  *orig = port; 
	      char  *dest = port + 3;
	      while((*orig++ = *dest++));
	      /* Update path position, Henry Minsky */
	      path -= 3;
	    }
	}
	else if (newname)
	  strncat (newname, port, (int) (path - port));
      }

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


/*----------------------------------------------------------------------
  SimplifyUrl: simplify a URI
  A URI is allowed to contain the sequence xxx/../ which may be
  replaced by "" , and the sequence "/./" which may be replaced by DIR_STR.
  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.
  ----------------------------------------------------------------------*/
void         SimplifyUrl (char **url)
{
  char   *path;
  char   *access;
  char   *newptr; 
  char   *p;
  char   *orig, *dest, *end;

  char      used_sep;
  ThotBool ddot_simplify; /* used to desactivate the double dot simplifcation:
			     something/../ simplification in relative URLs when they start with a ../ */


  if (!url || !*url)
    return;

  if (strchr (*url, URL_SEP))
      used_sep = URL_SEP;
  else
      used_sep = DIR_SEP;

  /* should we simplify double dot? */
  path = *url;
  if (*path == '.' && *(path + 1) == '.')
    ddot_simplify = FALSE;
  else
    ddot_simplify = TRUE;

  /* Find any scheme name */
  if ((path = strstr (*url, "://")) != NULL)
    {
      /* Find host name */
      access = *url;
      while (access < path && (*access = utolower (*access)))
            access++;
      path += 3;
      while ((newptr = strstr (path, "://")) != NULL)
            /* For proxies */
            path = newptr + 3;
     /* We have a host name */
      path = HTCanon (url, path);
    }
  else if ((path = strstr (*url, ":/")) != NULL)
    path += 2;
  else
    path = *url;

  if (*path == used_sep && *(path+1) == used_sep)
    /* Some URLs start //<foo> */
    path += 1;
  else if (IsFilePath (path))
    {
      /* doesn't need to do anything more */
      return;
    }
  else if (!strncmp (path, "news:", 5))
    {
      newptr = strchr (path+5, '@');
      if (!newptr)
	newptr = path + 5;
      while (*newptr)
	{
	  /* Make group or host lower case */
	  *newptr = utolower (*newptr);
	  newptr++;
	}
      /* Doesn't need to do any more */
      return;
    }

  if ((p = path))
    {
      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 we're pointing to a char, it's safe to reactivate the 
	     ../ convertion */
	  if (!ddot_simplify && *p != '.' && *p != used_sep)
	    ddot_simplify = TRUE;

	  if (*p==used_sep)
	    {
	      if (p > *url && *(p+1) == '.' && (*(p+2) == used_sep || !*(p+2)))
		{
		  orig = p + 1;
		  dest = (*(p+2) != used_sep) ? p+2 : p+3;
		  while ((*orig++ = *dest++)); /* Remove a used_sep and a dot*/
		  end = orig - 1;
		}
	      else if (ddot_simplify && *(p+1) == '.' && *(p+2) == '.' 
		       && (*(p+3) == used_sep || !*(p+3)))
		{
		  newptr = p;
		  while (newptr>path && *--newptr!=used_sep); /* prev used_sep */
		  if (*newptr == used_sep)
		    orig = newptr + 1;
		  else
		    orig = newptr;

		  dest = (*(p+3) != used_sep) ? p+3 : p+4;
		  while ((*orig++ = *dest++)); /* Remove /xxx/.. */
		  end = orig-1;
		  /* Start again with prev slash */
		  p = newptr;
		}
	      else if (*(p+1) == used_sep)
		{
		  while (*(p+1) == used_sep)
		    {
		      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 == used_sep && *(path+1) == '.' && *(path+2) == '.' 
	&& (!*(path+3) || *(path+3) == used_sep))
	*(path+1) = EOS;

  return;
}


/*----------------------------------------------------------------------
   NormalizeFile normalizes local names.                             
   Return TRUE if target and src differ.                           
  ----------------------------------------------------------------------*/
ThotBool NormalizeFile (char *src, char *target, ConvertionType convertion)
{
#ifndef _WINDOWS
   char             *s;
   int               i;
#endif /* !_WINDOWS */
   ThotBool          change;
   int               start_index; /* the first char that we'll copy */

   change = FALSE;
   start_index = 0;

   if (!src || src[0] == EOS)
     {
       target[0] = EOS;
       return FALSE;
     }

   /* @@ do I need file: or file:/ here? */
   if (strncmp (src, "file:", 5) == 0)
     {
       /* remove the prefix file: */
       start_index += 5;
   
       /* remove the localhost prefix */
       if (strncmp (&src[start_index], "//localhost/", 12) == 0)
	   start_index += 11;
       
       /* remove the first two slashes in / / /path */
       while (src[start_index] &&
	      src[start_index] == '/' 
	      && src[start_index + 1] == '/')
	 start_index++;

#ifdef _WINDOWS
       /* remove any extra slash before the drive name */
       if (src[start_index] == '/'
	   &&src[start_index+2] == ':')
	 start_index++;
#endif /* _WINDOWS */

       if (src[start_index] == EOS)
       /* if there's nothing afterwards, add a DIR_STR */
	 strcpy (target, DIR_STR);
       else
	 /* as we're inside a file: URL, we'll apply all the convertions
	    we know */
	 CleanCopyFileURL (target, &src[start_index], AM_CONV_ALL);

       change = TRUE;
     }
   else if (convertion != AM_CONV_NONE)
     {
       /* we are following a "local" relative link, we do all the
	  convertions except for the HOME_DIR ~ one */
       CleanCopyFileURL (target, src, convertion);
     }
#ifndef _WINDOWS
   else if (src[0] == '~')
     {
       /* it must be a URL typed in a text input field */
       /* do the HOME_DIR ~ substitution */
	s = TtaGetEnvString ("HOME");
	strcpy (target, s);
#if 0
	/* JK: invalidated this part of the code as it's simpler
	   to add the DIR_SEP whenever we have something to add
	   to the path rather than adding it systematically */
	if (src[1] != DIR_SEP)
	  strcat (target, DIR_STR);
#endif
	i = strlen (target);
	strcpy (&target[i], &src[1]);
	change = TRUE;
     }
#endif /* _WINDOWS */
   else
   /* leave it as it is */
     strcpy (target, src);
   
   /* remove /../ and /./ */
   SimplifyUrl (&target);
   if (!change)
     change = strcmp (src, target);
   return (change);
}


/*----------------------------------------------------------------------
  MakeRelativeURL: 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 AmayaParseUrl relative to relatedName, will yield aName.
  	The caller is responsible for freeing the resulting name later.
  ----------------------------------------------------------------------*/
char      *MakeRelativeURL (char *aName, char *relatedName)
{
  char  *return_value;
  char   result[MAX_LENGTH];
  char  *p;
  char  *q;
  char  *after_access;
  char  *last_slash = NULL;
  int    slashes, levels, len;
#ifdef _WINDOWS
  int ndx;
#endif /* _WINDOWS */

  if (aName == NULL || relatedName == NULL)
    return (NULL);

  slashes = 0;
  after_access = NULL;
  p = aName;
  q = relatedName;
  for (; *p && (*p == *q); p++, q++)
    {
      /* Find extent of match */
      if (*p == ':')
	after_access = p + 1;
      if (*p == DIR_SEP)
	{
	  /* memorize the last slash position and count them */
	  last_slash = p;
	  slashes++;
	}
    }
    
  /* q, p point to the first non-matching character or zero */
  if (*q == EOS)
    {
      /* New name is a subset of the related name */
      /* exactly the right length */
      len = strlen (p);
      if ((return_value = TtaGetMemory (len + 1)) != NULL)
	strcpy (return_value, p);
    }
  else if ((slashes < 2 && after_access == NULL)
      || (slashes < 3 && after_access != NULL))
    {
      /* Two names whitout common path */
      /* exactly the right length */
      len = strlen (aName);
      if ((return_value = TtaGetMemory (len + 1)) != NULL)
	strcpy (return_value, aName);
    }
  else
    {
      /* Some path in common */
      if (slashes == 3 && strncmp (aName, "http:", 5) == 0)
	/* just the same server */
	strcpy (result, last_slash);
      else
	{
	  levels= 0; 
	  for (; *q && *q != '#' && *q != ';' && *q != '?'; q++)
	    if (*q == DIR_SEP)
	      levels++;
	  
	  result[0] = EOS;
	  for (;levels; levels--)
	    strcat (result, "../");
	  strcat (result, last_slash+1);
	} 

      if (!*result)
	strcat (result, "./");

      /* exactly the right length */
      len = strlen (result);
      if ((return_value = TtaGetMemory (len + 1)) != NULL)
	strcpy (return_value, result);

    }
#ifdef _WINDOWS
  len = strlen (return_value);
  for (ndx = 0; ndx < len; ndx ++)
	  if (return_value[ndx] == '\\')
	     return_value[ndx] = '/' ;
#endif /* _WINDOWS */
  return (return_value);
}

/*----------------------------------------------------------------------
  AM_GetFileSize
  Returns TRUE and the filesize in the 2nd parameter.
  Otherwise, in case of a system error, returns FALSE, with a 
  filesize of 0L.
  ---------------------------------------------------------------------*/
ThotBool AM_GetFileSize (char *filename, unsigned long *file_size)
{
  ThotFileHandle   handle = ThotFile_BADHANDLE;
  ThotFileInfo     info;

  *file_size = 0L;
  if (!TtaFileExist (filename))
    return FALSE;

  handle = TtaFileOpen (filename, ThotFile_READWRITE);
  if (handle == ThotFile_BADHANDLE)
    /* ThotFile_BADHANDLE */
    return FALSE;
   if (TtaFileStat (handle, &info) == 0)
     /* bad stat */
     info.size = 0L;
   TtaFileClose (handle);
   *file_size = (unsigned long) info.size;
   return TRUE;
}