Edit

kc3-lang/libxml2/uri.c

Branch :

  • Show log

    Commit

  • Author : Daniel Veillard
    Date : 2000-11-06 16:43:11
    Hash : 9e8bfae5
    Message : XInclude and other stuff while travelling. Contributed patches: - tree.[ch] xinclude.[ch] xmllint.c configure.in valid.c debugXML.c xmlversion.h.in: Started adding XInclude support, this is a new xmllint option - tree.c xpath.c: applied TOM patches for XPath - xpointer.c: fixed a couple of errors. - uri.c: added an escaping function needed for xinclude - testXPath.c hash.c HTMLtree.c: minor cleanups raised by new warning from RH70 gcc's version Daniel

  • uri.c
  • /**
     * uri.c: set of generic URI related routines 
     *
     * Reference: RFC 2396
     *
     * See Copyright for the status of this software.
     *
     * Daniel.Veillard@w3.org
     */
    
    #ifdef WIN32
    #define INCLUDE_WINSOCK
    #include "win32config.h"
    #else
    #include "config.h"
    #endif
    
    #include <stdio.h>
    #include <string.h>
    
    #include <libxml/xmlmemory.h>
    #include <libxml/uri.h>
    #include <libxml/xmlerror.h>
    
    /************************************************************************
     *									*
     *		Macros to differenciate various character type		*
     *			directly extracted from RFC 2396		*
     *									*
     ************************************************************************/
    
    /*
     * alpha    = lowalpha | upalpha
     */
    #define IS_ALPHA(x) (IS_LOWALPHA(x) || IS_UPALPHA(x))
    
    
    /*
     * lowalpha = "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" | "i" | "j" |
     *            "k" | "l" | "m" | "n" | "o" | "p" | "q" | "r" | "s" | "t" |
     *            "u" | "v" | "w" | "x" | "y" | "z"
     */
    
    #define IS_LOWALPHA(x) (((x) >= 'a') && ((x) <= 'z'))
    
    /*
     * upalpha = "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" | "J" |
     *           "K" | "L" | "M" | "N" | "O" | "P" | "Q" | "R" | "S" | "T" |
     *           "U" | "V" | "W" | "X" | "Y" | "Z"
     */
    #define IS_UPALPHA(x) (((x) >= 'A') && ((x) <= 'Z'))
    
    /*
     * digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
     */
    
    #define IS_DIGIT(x) (((x) >= '0') && ((x) <= '9'))
    
    /*
     * alphanum = alpha | digit
     */
    
    #define IS_ALPHANUM(x) (IS_ALPHA(x) || IS_DIGIT(x))
    
    /*
     * hex = digit | "A" | "B" | "C" | "D" | "E" | "F" |
     *               "a" | "b" | "c" | "d" | "e" | "f"
     */
    
    #define IS_HEX(x) ((IS_DIGIT(x)) || (((x) >= 'a') && ((x) <= 'f')) || \
    	    (((x) >= 'A') && ((x) <= 'F')))
    
    /*
     * mark = "-" | "_" | "." | "!" | "~" | "*" | "'" | "(" | ")"
     */
    
    #define IS_MARK(x) (((x) == '-') || ((x) == '_') || ((x) == '.') ||	\
        ((x) == '!') || ((x) == '~') || ((x) == '*') || ((x) == '\'') ||	\
        ((x) == '(') || ((x) == ')'))
    
    
    /*
     * reserved = ";" | "/" | "?" | ":" | "@" | "&" | "=" | "+" | "$" | ","
     */
    
    #define IS_RESERVED(x) (((x) == ';') || ((x) == '/') || ((x) == '?') ||	\
            ((x) == ':') || ((x) == '@') || ((x) == '&') || ((x) == '=') ||	\
    	((x) == '+') || ((x) == '$') || ((x) == ','))
    
    /*
     * unreserved = alphanum | mark
     */
    
    #define IS_UNRESERVED(x) (IS_ALPHANUM(x) || IS_MARK(x))
    
    /*
     * escaped = "%" hex hex
     */
    
    #define IS_ESCAPED(p) ((*(p) == '%') && (IS_HEX((p)[1])) &&		\
    	    (IS_HEX((p)[2])))
    
    /*
     * uric_no_slash = unreserved | escaped | ";" | "?" | ":" | "@" |
     *                        "&" | "=" | "+" | "$" | ","
     */
    #define IS_URIC_NO_SLASH(p) ((IS_UNRESERVED(*(p))) || (IS_ESCAPED(p)) ||\
    	        ((*(p) == ';')) || ((*(p) == '?')) || ((*(p) == ':')) ||\
    	        ((*(p) == '@')) || ((*(p) == '&')) || ((*(p) == '=')) ||\
    	        ((*(p) == '+')) || ((*(p) == '$')) || ((*(p) == ',')))
    
    /*
     * pchar = unreserved | escaped | ":" | "@" | "&" | "=" | "+" | "$" | ","
     */
    #define IS_PCHAR(p) ((IS_UNRESERVED(*(p))) || (IS_ESCAPED(p)) ||	\
    	        ((*(p) == ':')) || ((*(p) == '@')) || ((*(p) == '&')) ||\
    	        ((*(p) == '=')) || ((*(p) == '+')) || ((*(p) == '$')) ||\
    	        ((*(p) == ',')))
    
    /*
     * rel_segment   = 1*( unreserved | escaped |
     *                 ";" | "@" | "&" | "=" | "+" | "$" | "," )
     */
    
    #define IS_SEGMENT(p) ((IS_UNRESERVED(*(p))) || (IS_ESCAPED(p)) ||	\
              ((*(p) == ';')) || ((*(p) == '@')) || ((*(p) == '&')) ||	\
    	  ((*(p) == '=')) || ((*(p) == '+')) || ((*(p) == '$')) ||	\
    	  ((*(p) == ',')))
    
    /*
     * scheme = alpha *( alpha | digit | "+" | "-" | "." )
     */
    
    #define IS_SCHEME(x) ((IS_ALPHA(x)) || (IS_DIGIT(x)) ||			\
    	              ((x) == '+') || ((x) == '-') || ((x) == '.'))
    
    /*
     * reg_name = 1*( unreserved | escaped | "$" | "," |
     *                ";" | ":" | "@" | "&" | "=" | "+" )
     */
    
    #define IS_REG_NAME(p) ((IS_UNRESERVED(*(p))) || (IS_ESCAPED(p)) ||	\
           ((*(p) == '$')) || ((*(p) == ',')) || ((*(p) == ';')) ||		\
           ((*(p) == ':')) || ((*(p) == '@')) || ((*(p) == '&')) ||		\
           ((*(p) == '=')) || ((*(p) == '+')))
    
    /*
     * userinfo = *( unreserved | escaped | ";" | ":" | "&" | "=" |
     *                      "+" | "$" | "," )
     */
    #define IS_USERINFO(p) ((IS_UNRESERVED(*(p))) || (IS_ESCAPED(p)) ||	\
           ((*(p) == ';')) || ((*(p) == ':')) || ((*(p) == '&')) ||		\
           ((*(p) == '=')) || ((*(p) == '+')) || ((*(p) == '$')) ||		\
           ((*(p) == ',')))
    
    /*
     * uric = reserved | unreserved | escaped
     */
    
    #define IS_URIC(p) ((IS_UNRESERVED(*(p))) || (IS_ESCAPED(p)) ||		\
    	            (IS_RESERVED(*(p))))
    
    /*
     * Skip to next pointer char, handle escaped sequences
     */
    
    #define NEXT(p) ((*p == '%')? p += 3 : p++)
    
    /*
     * Productions from the spec.
     *
     *    authority     = server | reg_name
     *    reg_name      = 1*( unreserved | escaped | "$" | "," |
     *                        ";" | ":" | "@" | "&" | "=" | "+" )
     *
     * path          = [ abs_path | opaque_part ]
     */
    
    /************************************************************************
     *									*
     *			Generic URI structure functions			*
     *									*
     ************************************************************************/
    
    /**
     * xmlCreateURI:
     *
     * Simply creates an empty xmlURI
     *
     * Returns the new structure or NULL in case of error
     */
    xmlURIPtr
    xmlCreateURI(void) {
        xmlURIPtr ret;
    
        ret = (xmlURIPtr) xmlMalloc(sizeof(xmlURI));
        if (ret == NULL) {
    	xmlGenericError(xmlGenericErrorContext,
    		"xmlCreateURI: out of memory\n");
    	return(NULL);
        }
        memset(ret, 0, sizeof(xmlURI));
        return(ret);
    }
    
    /**
     * xmlSaveUri:
     * @uri:  pointer to an xmlURI
     *
     * Save the URI as an escaped string
     *
     * Returns a new string (to be deallocated by caller)
     */
    xmlChar *
    xmlSaveUri(xmlURIPtr uri) {
        xmlChar *ret = NULL;
        const char *p;
        int len;
        int max;
    
        if (uri == NULL) return(NULL);
    
    
        max = 80;
        ret = (xmlChar *) xmlMalloc((max + 1) * sizeof(xmlChar));
        if (ret == NULL) {
    	xmlGenericError(xmlGenericErrorContext,
    		"xmlSaveUri: out of memory\n");
    	return(NULL);
        }
        len = 0;
    
        if (uri->scheme != NULL) {
    	p = uri->scheme;
    	while (*p != 0) {
    	    if (len >= max) {
    		max *= 2;
    		ret = (xmlChar *) xmlRealloc(ret, (max + 1) * sizeof(xmlChar));
    		if (ret == NULL) {
    		    xmlGenericError(xmlGenericErrorContext,
    			    "xmlSaveUri: out of memory\n");
    		    return(NULL);
    		}
    	    }
    	    ret[len++] = *p++;
    	}
    	if (len >= max) {
    	    max *= 2;
    	    ret = (xmlChar *) xmlRealloc(ret, (max + 1) * sizeof(xmlChar));
    	    if (ret == NULL) {
    		xmlGenericError(xmlGenericErrorContext,
    			"xmlSaveUri: out of memory\n");
    		return(NULL);
    	    }
    	}
    	ret[len++] = ':';
        }
        if (uri->opaque != NULL) {
    	p = uri->opaque;
    	while (*p != 0) {
    	    if (len + 3 >= max) {
    		max *= 2;
    		ret = (xmlChar *) xmlRealloc(ret, (max + 1) * sizeof(xmlChar));
    		if (ret == NULL) {
    		    xmlGenericError(xmlGenericErrorContext,
    			    "xmlSaveUri: out of memory\n");
    		    return(NULL);
    		}
    	    }
    	    if ((IS_UNRESERVED(*(p))) ||
    	        ((*(p) == ';')) || ((*(p) == '?')) || ((*(p) == ':')) ||
    	        ((*(p) == '@')) || ((*(p) == '&')) || ((*(p) == '=')) ||
    	        ((*(p) == '+')) || ((*(p) == '$')) || ((*(p) == ',')))
    		ret[len++] = *p++;
    	    else {
    		int val = *(unsigned char *)p++;
    		int hi = val / 0x10, lo = val % 0x10;
    		ret[len++] = '%';
    		ret[len++] = hi + (hi > 9? 'A'-10 : '0');
    		ret[len++] = lo + (lo > 9? 'A'-10 : '0');
    	    }
    	}
    	if (len >= max) {
    	    max *= 2;
    	    ret = (xmlChar *) xmlRealloc(ret, (max + 1) * sizeof(xmlChar));
    	    if (ret == NULL) {
    		xmlGenericError(xmlGenericErrorContext,
    			"xmlSaveUri: out of memory\n");
    		return(NULL);
    	    }
    	}
    	ret[len++] = 0;
        } else {
    	if (uri->server != NULL) {
    	    if (len + 3 >= max) {
    		max *= 2;
    		ret = (xmlChar *) xmlRealloc(ret, (max + 1) * sizeof(xmlChar));
    		if (ret == NULL) {
    		    xmlGenericError(xmlGenericErrorContext,
    			    "xmlSaveUri: out of memory\n");
    		    return(NULL);
    		}
    	    }
    	    ret[len++] = '/';
    	    ret[len++] = '/';
    	    if (uri->user != NULL) {
    		p = uri->user;
    		while (*p != 0) {
    		    if (len + 3 >= max) {
    			max *= 2;
    			ret = (xmlChar *) xmlRealloc(ret,
    				(max + 1) * sizeof(xmlChar));
    			if (ret == NULL) {
    			    xmlGenericError(xmlGenericErrorContext,
    				    "xmlSaveUri: out of memory\n");
    			    return(NULL);
    			}
    		    }
    		    if ((IS_UNRESERVED(*(p))) ||
    			((*(p) == ';')) || ((*(p) == ':')) ||
    			((*(p) == '&')) || ((*(p) == '=')) ||
    			((*(p) == '+')) || ((*(p) == '$')) ||
    			((*(p) == ',')))
    			ret[len++] = *p++;
    		    else {
    			int val = *(unsigned char *)p++;
    			int hi = val / 0x10, lo = val % 0x10;
    			ret[len++] = '%';
    			ret[len++] = hi + (hi > 9? 'A'-10 : '0');
    			ret[len++] = lo + (lo > 9? 'A'-10 : '0');
    		    }
    		}
    		if (len + 3 >= max) {
    		    max *= 2;
    		    ret = (xmlChar *) xmlRealloc(ret,
    			    (max + 1) * sizeof(xmlChar));
    		    if (ret == NULL) {
    			xmlGenericError(xmlGenericErrorContext,
    				"xmlSaveUri: out of memory\n");
    			return(NULL);
    		    }
    		}
    		ret[len++] = '@';
    	    }
    	    p = uri->server;
    	    while (*p != 0) {
    		if (len >= max) {
    		    max *= 2;
    		    ret = (xmlChar *) xmlRealloc(ret,
    			    (max + 1) * sizeof(xmlChar));
    		    if (ret == NULL) {
    			xmlGenericError(xmlGenericErrorContext,
    				"xmlSaveUri: out of memory\n");
    			return(NULL);
    		    }
    		}
    		ret[len++] = *p++;
    	    }
    	    if (uri->port > 0) {
    		if (len + 10 >= max) {
    		    max *= 2;
    		    ret = (xmlChar *) xmlRealloc(ret,
    			    (max + 1) * sizeof(xmlChar));
    		    if (ret == NULL) {
    			xmlGenericError(xmlGenericErrorContext,
    				"xmlSaveUri: out of memory\n");
    			return(NULL);
    		    }
    		}
    		len += sprintf((char *) &ret[len], ":%d", uri->port);
    	    }
    	} else if (uri->authority != NULL) {
    	    if (len + 3 >= max) {
    		max *= 2;
    		ret = (xmlChar *) xmlRealloc(ret,
    			(max + 1) * sizeof(xmlChar));
    		if (ret == NULL) {
    		    xmlGenericError(xmlGenericErrorContext,
    			    "xmlSaveUri: out of memory\n");
    		    return(NULL);
    		}
    	    }
    	    ret[len++] = '/';
    	    ret[len++] = '/';
    	    p = uri->authority;
    	    while (*p != 0) {
    		if (len + 3 >= max) {
    		    max *= 2;
    		    ret = (xmlChar *) xmlRealloc(ret,
    			    (max + 1) * sizeof(xmlChar));
    		    if (ret == NULL) {
    			xmlGenericError(xmlGenericErrorContext,
    				"xmlSaveUri: out of memory\n");
    			return(NULL);
    		    }
    		}
    		if ((IS_UNRESERVED(*(p))) ||
                        ((*(p) == '$')) || ((*(p) == ',')) || ((*(p) == ';')) ||
                        ((*(p) == ':')) || ((*(p) == '@')) || ((*(p) == '&')) ||
                        ((*(p) == '=')) || ((*(p) == '+')))
    		    ret[len++] = *p++;
    		else {
    		    int val = *(unsigned char *)p++;
    		    int hi = val / 0x10, lo = val % 0x10;
    		    ret[len++] = '%';
    		    ret[len++] = hi + (hi > 9? 'A'-10 : '0');
    		    ret[len++] = lo + (lo > 9? 'A'-10 : '0');
    		}
    	    }
    	} else if (uri->scheme != NULL) {
    	    if (len + 3 >= max) {
    		max *= 2;
    		ret = (xmlChar *) xmlRealloc(ret,
    			(max + 1) * sizeof(xmlChar));
    		if (ret == NULL) {
    		    xmlGenericError(xmlGenericErrorContext,
    			    "xmlSaveUri: out of memory\n");
    		    return(NULL);
    		}
    	    }
    	    ret[len++] = '/';
    	    ret[len++] = '/';
    	}
    	if (uri->path != NULL) {
    	    p = uri->path;
    	    while (*p != 0) {
    		if (len + 3 >= max) {
    		    max *= 2;
    		    ret = (xmlChar *) xmlRealloc(ret,
    			    (max + 1) * sizeof(xmlChar));
    		    if (ret == NULL) {
    			xmlGenericError(xmlGenericErrorContext,
    				"xmlSaveUri: out of memory\n");
    			return(NULL);
    		    }
    		}
    		if ((IS_UNRESERVED(*(p))) || ((*(p) == '/')) ||
                        ((*(p) == ';')) || ((*(p) == '@')) || ((*(p) == '&')) ||
    	            ((*(p) == '=')) || ((*(p) == '+')) || ((*(p) == '$')) ||
    	            ((*(p) == ',')))
    		    ret[len++] = *p++;
    		else {
    		    int val = *(unsigned char *)p++;
    		    int hi = val / 0x10, lo = val % 0x10;
    		    ret[len++] = '%';
    		    ret[len++] = hi + (hi > 9? 'A'-10 : '0');
    		    ret[len++] = lo + (lo > 9? 'A'-10 : '0');
    		}
    	    }
    	}
    	if (uri->query != NULL) {
    	    if (len + 3 >= max) {
    		max *= 2;
    		ret = (xmlChar *) xmlRealloc(ret,
    			(max + 1) * sizeof(xmlChar));
    		if (ret == NULL) {
    		    xmlGenericError(xmlGenericErrorContext,
    			    "xmlSaveUri: out of memory\n");
    		    return(NULL);
    		}
    	    }
    	    ret[len++] = '?';
    	    p = uri->query;
    	    while (*p != 0) {
    		if (len + 3 >= max) {
    		    max *= 2;
    		    ret = (xmlChar *) xmlRealloc(ret,
    			    (max + 1) * sizeof(xmlChar));
    		    if (ret == NULL) {
    			xmlGenericError(xmlGenericErrorContext,
    				"xmlSaveUri: out of memory\n");
    			return(NULL);
    		    }
    		}
    		if ((IS_UNRESERVED(*(p))) || (IS_RESERVED(*(p)))) 
    		    ret[len++] = *p++;
    		else {
    		    int val = *(unsigned char *)p++;
    		    int hi = val / 0x10, lo = val % 0x10;
    		    ret[len++] = '%';
    		    ret[len++] = hi + (hi > 9? 'A'-10 : '0');
    		    ret[len++] = lo + (lo > 9? 'A'-10 : '0');
    		}
    	    }
    	}
    	if (uri->fragment != NULL) {
    	    if (len + 3 >= max) {
    		max *= 2;
    		ret = (xmlChar *) xmlRealloc(ret,
    			(max + 1) * sizeof(xmlChar));
    		if (ret == NULL) {
    		    xmlGenericError(xmlGenericErrorContext,
    			    "xmlSaveUri: out of memory\n");
    		    return(NULL);
    		}
    	    }
    	    ret[len++] = '#';
    	    p = uri->fragment;
    	    while (*p != 0) {
    		if (len + 3 >= max) {
    		    max *= 2;
    		    ret = (xmlChar *) xmlRealloc(ret,
    			    (max + 1) * sizeof(xmlChar));
    		    if (ret == NULL) {
    			xmlGenericError(xmlGenericErrorContext,
    				"xmlSaveUri: out of memory\n");
    			return(NULL);
    		    }
    		}
    		if ((IS_UNRESERVED(*(p))) || (IS_RESERVED(*(p)))) 
    		    ret[len++] = *p++;
    		else {
    		    int val = *(unsigned char *)p++;
    		    int hi = val / 0x10, lo = val % 0x10;
    		    ret[len++] = '%';
    		    ret[len++] = hi + (hi > 9? 'A'-10 : '0');
    		    ret[len++] = lo + (lo > 9? 'A'-10 : '0');
    		}
    	    }
    	}
    	if (len >= max) {
    	    max *= 2;
    	    ret = (xmlChar *) xmlRealloc(ret, (max + 1) * sizeof(xmlChar));
    	    if (ret == NULL) {
    		xmlGenericError(xmlGenericErrorContext,
    			"xmlSaveUri: out of memory\n");
    		return(NULL);
    	    }
    	}
    	ret[len++] = 0;
        }
        return(ret);
    }
    
    /**
     * xmlPrintURI:
     * @stream:  a FILE* for the output
     * @uri:  pointer to an xmlURI
     *
     * Prints the URI in the stream @steam.
     */
    void
    xmlPrintURI(FILE *stream, xmlURIPtr uri) {
        xmlChar *out;
    
        out = xmlSaveUri(uri);
        if (out != NULL) {
    	fprintf(stream, "%s", out);
    	xmlFree(out);
        }
    }
    
    /**
     * xmlCleanURI:
     * @uri:  pointer to an xmlURI
     *
     * Make sure the xmlURI struct is free of content
     */
    void
    xmlCleanURI(xmlURIPtr uri) {
        if (uri == NULL) return;
    
        if (uri->scheme != NULL) xmlFree(uri->scheme);
        uri->scheme = NULL;
        if (uri->server != NULL) xmlFree(uri->server);
        uri->server = NULL;
        if (uri->user != NULL) xmlFree(uri->user);
        uri->user = NULL;
        if (uri->path != NULL) xmlFree(uri->path);
        uri->path = NULL;
        if (uri->fragment != NULL) xmlFree(uri->fragment);
        uri->fragment = NULL;
        if (uri->opaque != NULL) xmlFree(uri->opaque);
        uri->opaque = NULL;
        if (uri->authority != NULL) xmlFree(uri->authority);
        uri->authority = NULL;
        if (uri->query != NULL) xmlFree(uri->query);
        uri->query = NULL;
    }
    
    /**
     * xmlFreeURI:
     * @uri:  pointer to an xmlURI
     *
     * Free up the xmlURI struct
     */
    void
    xmlFreeURI(xmlURIPtr uri) {
        if (uri == NULL) return;
    
        if (uri->scheme != NULL) xmlFree(uri->scheme);
        if (uri->server != NULL) xmlFree(uri->server);
        if (uri->user != NULL) xmlFree(uri->user);
        if (uri->path != NULL) xmlFree(uri->path);
        if (uri->fragment != NULL) xmlFree(uri->fragment);
        if (uri->opaque != NULL) xmlFree(uri->opaque);
        if (uri->authority != NULL) xmlFree(uri->authority);
        if (uri->query != NULL) xmlFree(uri->query);
        memset(uri, -1, sizeof(xmlURI));
        xmlFree(uri);
    }
    
    /************************************************************************
     *									*
     *			Helper functions				*
     *									*
     ************************************************************************/
    
    /**
     * xmlNormalizeURIPath:
     * @path:  pointer to the path string
     *
     * applies the 5 normalization steps to a path string
     * Normalization occurs directly on the string, no new allocation is done
     *
     * Returns 0 or an error code
     */
    int
    xmlNormalizeURIPath(char *path) {
        int cur, out;
    
        if (path == NULL)
    	return(-1);
        cur = 0;
        out = 0;
        while ((path[cur] != 0) && (path[cur] != '/')) cur++;
        if (path[cur] == 0)
    	return(0);
    
        /* we are positionned at the beginning of the first segment */
        cur++;
        out = cur;
    
        /*
         * Analyze each segment in sequence.
         */
        while (path[cur] != 0) {
    	/*
    	 * c) All occurrences of "./", where "." is a complete path segment,
    	 *    are removed from the buffer string.
    	 */
    	if ((path[cur] == '.') && (path[cur + 1] == '/')) {
    	    cur += 2;
    	    continue;
    	}
    
    	/*
    	 * d) If the buffer string ends with "." as a complete path segment,
    	 *    that "." is removed.
    	 */
    	if ((path[cur] == '.') && (path[cur + 1] == 0)) {
    	    path[out] = 0;
    	    break;
    	}
    
    	/* read the segment */
    	while ((path[cur] != 0) && (path[cur] != '/')) {
    	    path[out++] = path[cur++];
    	}
    	path[out++] = path[cur];
    	if (path[cur] != 0) {
    	    cur++;
    	}
        }
    
        cur = 0;
        out = 0;
        while ((path[cur] != 0) && (path[cur] != '/')) cur++;
        if (path[cur] == 0)
    	return(0);
        /* we are positionned at the beginning of the first segment */
        cur++;
        out = cur;
        /*
         * Analyze each segment in sequence.
         */
        while (path[cur] != 0) {
    	/*
    	 * e) All occurrences of "<segment>/../", where <segment> is a
    	 *    complete path segment not equal to "..", are removed from the
    	 *    buffer string.  Removal of these path segments is performed
    	 *    iteratively, removing the leftmost matching pattern on each
    	 *    iteration, until no matching pattern remains.
    	 */
    	if ((cur > 1) && (out > 1) &&
    	    (path[cur] == '/') && (path[cur + 1] == '.') &&
    	    (path[cur + 2] == '.') && (path[cur + 3] == '/') &&
    	    ((path[out] != '.') || (path[out - 1] != '.') ||
    	     (path[out - 2] != '/'))) {
    	    cur += 3;
    	    out --;
    	    while ((out > 0) && (path[out] != '/')) { out --; }
    	    path[out] = 0;
                continue;
    	}
    
    	/*
    	 * f) If the buffer string ends with "<segment>/..", where <segment>
    	 *    is a complete path segment not equal to "..", that
    	 *    "<segment>/.." is removed.
    	 */
    	if ((path[cur] == '/') && (path[cur + 1] == '.') &&
    	    (path[cur + 2] == '.') && (path[cur + 3] == 0) &&
    	    ((path[out] != '.') || (path[out - 1] != '.') ||
    	     (path[out - 2] != '/'))) {
    	    cur += 4;
    	    out --;
    	    while ((out > 0) && (path[out - 1] != '/')) { out --; }
    	    path[out] = 0;
                continue;
    	}
            
    	path[out++] = path[cur++]; /* / or 0 */
        }
        path[out] = 0;
    
        /*
         * g) If the resulting buffer string still begins with one or more
         *    complete path segments of "..", then the reference is 
         *    considered to be in error. Implementations may handle this
         *    error by retaining these components in the resolved path (i.e.,
         *    treating them as part of the final URI), by removing them from
         *    the resolved path (i.e., discarding relative levels above the
         *    root), or by avoiding traversal of the reference.
         *
         * We discard them from the final path.
         */
        cur = 0;
        while ((path[cur] == '/') && (path[cur + 1] == '.') &&
    	   (path[cur + 2] == '.'))
    	cur += 3;
        if (cur != 0) {
    	out = 0;
    	while (path[cur] != 0) path[out++] = path[cur++];
    	path[out] = 0;
        }
        return(0);
    }
    
    /**
     * xmlURIUnescapeString:
     * @str:  the string to unescape
     * @len:   the lenght in bytes to unescape (or <= 0 to indicate full string)
     * @target:  optionnal destination buffer
     *
     * Unescaping routine, does not do validity checks !
     * Output is direct unsigned char translation of %XX values (no encoding)
     *
     * Returns an copy of the string, but unescaped
     */
    char *
    xmlURIUnescapeString(const char *str, int len, char *target) {
        char *ret, *out;
        const char *in;
    
        if (str == NULL)
    	return(NULL);
        if (len <= 0) len = strlen(str);
        if (len <= 0) return(NULL);
    
        if (target == NULL) {
    	ret = (char *) xmlMalloc(len + 1);
    	if (ret == NULL) {
    	    xmlGenericError(xmlGenericErrorContext,
    		    "xmlURIUnescapeString: out of memory\n");
    	    return(NULL);
    	}
        } else
    	ret = target;
        in = str;
        out = ret;
        while(len > 0) {
    	if (*in == '%') {
    	    in++;
    	    if ((*in >= '0') && (*in <= '9')) 
    	        *out = (*in - '0');
    	    else if ((*in >= 'a') && (*in <= 'f'))
    	        *out = (*in - 'a') + 10;
    	    else if ((*in >= 'A') && (*in <= 'F'))
    	        *out = (*in - 'A') + 10;
    	    in++;
    	    if ((*in >= '0') && (*in <= '9')) 
    	        *out = *out * 16 + (*in - '0');
    	    else if ((*in >= 'a') && (*in <= 'f'))
    	        *out = *out * 16 + (*in - 'a') + 10;
    	    else if ((*in >= 'A') && (*in <= 'F'))
    	        *out = *out * 16 + (*in - 'A') + 10;
    	    in++;
    	    len -= 3;
    	    out++;
    	} else {
    	    *out++ = *in++;
    	    len--;
    	}
        }
        *out = 0;
        return(ret);
    }
    
    /**
     * xmlURIEscape:
     * @str:  the string of the URI to escape
     *
     * Escaping routine, does not do validity checks !
     * It will try to escape the chars needing this, but this is heuristic
     * based it's impossible to be sure.
     *
     * Returns an copy of the string, but escaped
     */
    xmlChar *
    xmlURIEscape(const xmlChar *str) {
        xmlChar *ret;
        const xmlChar *in;
        unsigned int len, out;
    
        if (str == NULL)
    	return(NULL);
        len = xmlStrlen(str);
        if (len <= 0) return(NULL);
    
        len += 20;
        ret = (xmlChar *) xmlMalloc(len);
        if (ret == NULL) {
    	xmlGenericError(xmlGenericErrorContext,
    		"xmlURIEscape: out of memory\n");
    	return(NULL);
        }
        in = (const xmlChar *) str;
        out = 0;
        while(*in != 0) {
    	if (len - out <= 3) {
    	    len += 20;
    	    ret = (xmlChar *) xmlRealloc(ret, len);
    	    if (ret == NULL) {
    		xmlGenericError(xmlGenericErrorContext,
    			"xmlURIEscape: out of memory\n");
    		return(NULL);
    	    }
    	}
    	if ((!IS_UNRESERVED(*in)) && (*in != ':') && (*in != '/') &&
    	    (*in != '?') && (*in != '#')) {
    	    unsigned char val;
    	    ret[out++] = '%';
    	    val = *in >> 4;
    	    if (val <= 9)
    		ret[out++] = '0' + val;
    	    else
    		ret[out++] = 'A' + val - 0xA;
    	    val = *in & 0xF;
    	    if (val <= 9)
    		ret[out++] = '0' + val;
    	    else
    		ret[out++] = 'A' + val - 0xA;
    	    in++;
    	} else {
    	    ret[out++] = *in++;
    	}
        }
        ret[out] = 0;
        return(ret);
    }
    
    /************************************************************************
     *									*
     *			Escaped URI parsing				*
     *									*
     ************************************************************************/
    
    /**
     * xmlParseURIFragment:
     * @uri:  pointer to an URI structure
     * @str:  pointer to the string to analyze
     *
     * Parse an URI fragment string and fills in the appropriate fields
     * of the @uri structure.
     * 
     * fragment = *uric
     *
     * Returns 0 or the error code
     */
    int
    xmlParseURIFragment(xmlURIPtr uri, const char **str) {
        const char *cur = *str;
    
        if (str == NULL) return(-1);
    
        while (IS_URIC(cur)) NEXT(cur);
        if (uri != NULL) {
    	if (uri->fragment != NULL) xmlFree(uri->fragment);
    	uri->fragment = xmlURIUnescapeString(*str, cur - *str, NULL);
        }
        *str = cur;
        return(0);
    }
    
    /**
     * xmlParseURIQuery:
     * @uri:  pointer to an URI structure
     * @str:  pointer to the string to analyze
     *
     * Parse the query part of an URI
     * 
     * query = *uric
     *
     * Returns 0 or the error code
     */
    int
    xmlParseURIQuery(xmlURIPtr uri, const char **str) {
        const char *cur = *str;
    
        if (str == NULL) return(-1);
    
        while (IS_URIC(cur)) NEXT(cur);
        if (uri != NULL) {
    	if (uri->query != NULL) xmlFree(uri->query);
    	uri->query = xmlURIUnescapeString(*str, cur - *str, NULL);
        }
        *str = cur;
        return(0);
    }
    
    /**
     * xmlParseURIScheme:
     * @uri:  pointer to an URI structure
     * @str:  pointer to the string to analyze
     *
     * Parse an URI scheme
     * 
     * scheme = alpha *( alpha | digit | "+" | "-" | "." )
     *
     * Returns 0 or the error code
     */
    int
    xmlParseURIScheme(xmlURIPtr uri, const char **str) {
        const char *cur;
    
        if (str == NULL)
    	return(-1);
        
        cur = *str;
        if (!IS_ALPHA(*cur))
    	return(2);
        cur++;
        while (IS_SCHEME(*cur)) cur++;
        if (uri != NULL) {
    	if (uri->scheme != NULL) xmlFree(uri->scheme);
    	/* !!! strndup */
    	uri->scheme = xmlURIUnescapeString(*str, cur - *str, NULL);
        }
        *str = cur;
        return(0);
    }
    
    /**
     * xmlParseURIOpaquePart:
     * @uri:  pointer to an URI structure
     * @str:  pointer to the string to analyze
     *
     * Parse an URI opaque part
     * 
     * opaque_part = uric_no_slash *uric
     *
     * Returns 0 or the error code
     */
    int
    xmlParseURIOpaquePart(xmlURIPtr uri, const char **str) {
        const char *cur;
    
        if (str == NULL)
    	return(-1);
        
        cur = *str;
        if (!IS_URIC_NO_SLASH(cur)) {
    	return(3);
        }
        NEXT(cur);
        while (IS_URIC(cur)) NEXT(cur);
        if (uri != NULL) {
    	if (uri->opaque != NULL) xmlFree(uri->opaque);
    	uri->opaque = xmlURIUnescapeString(*str, cur - *str, NULL);
        }
        *str = cur;
        return(0);
    }
    
    /**
     * xmlParseURIServer:
     * @uri:  pointer to an URI structure
     * @str:  pointer to the string to analyze
     *
     * Parse a server subpart of an URI, it's a finer grain analysis
     * of the authority part.
     * 
     * server        = [ [ userinfo "@" ] hostport ]
     * userinfo      = *( unreserved | escaped |
     *                       ";" | ":" | "&" | "=" | "+" | "$" | "," )
     * hostport      = host [ ":" port ]
     * host          = hostname | IPv4address
     * hostname      = *( domainlabel "." ) toplabel [ "." ]
     * domainlabel   = alphanum | alphanum *( alphanum | "-" ) alphanum
     * toplabel      = alpha | alpha *( alphanum | "-" ) alphanum
     * IPv4address   = 1*digit "." 1*digit "." 1*digit "." 1*digit
     * port          = *digit
     *
     * Returns 0 or the error code
     */
    int
    xmlParseURIServer(xmlURIPtr uri, const char **str) {
        const char *cur;
        const char *host, *tmp;
    
        if (str == NULL)
    	return(-1);
        
        cur = *str;
    
        /*
         * is there an userinfo ?
         */
        while (IS_USERINFO(cur)) NEXT(cur);
        if (*cur == '@') {
    	if (uri != NULL) {
    	    if (uri->user != NULL) xmlFree(uri->user);
    	    uri->user = xmlURIUnescapeString(*str, cur - *str, NULL);
    	}
    	cur++;
        } else {
    	if (uri != NULL) {
    	    if (uri->user != NULL) xmlFree(uri->user);
    	    uri->user = NULL;
    	}
            cur = *str;
        }
        /*
         * This can be empty in the case where there is no server
         */
        host = cur;
        if (*cur == '/') {
    	if (uri != NULL) {
    	    if (uri->authority != NULL) xmlFree(uri->authority);
    	    uri->authority = NULL;
    	    if (uri->server != NULL) xmlFree(uri->server);
    	    uri->server = NULL;
    	    uri->port = 0;
    	}
    	return(0);
        }
        /*
         * host part of hostport can derive either an IPV4 address
         * or an unresolved name. Check the IP first, it easier to detect
         * errors if wrong one
         */
        if (IS_DIGIT(*cur)) {
            while(IS_DIGIT(*cur)) cur++;
    	if (*cur != '.')
    	    goto host_name;
    	cur++;
    	if (!IS_DIGIT(*cur))
    	    goto host_name;
            while(IS_DIGIT(*cur)) cur++;
    	if (*cur != '.')
    	    goto host_name;
    	cur++;
    	if (!IS_DIGIT(*cur))
    	    goto host_name;
            while(IS_DIGIT(*cur)) cur++;
    	if (*cur != '.')
    	    goto host_name;
    	cur++;
    	if (!IS_DIGIT(*cur))
    	    goto host_name;
            while(IS_DIGIT(*cur)) cur++;
    	if (uri != NULL) {
    	    if (uri->authority != NULL) xmlFree(uri->authority);
    	    uri->authority = NULL;
    	    if (uri->server != NULL) xmlFree(uri->server);
    	    uri->server = xmlURIUnescapeString(host, cur - host, NULL);
    	}
    	goto host_done;
        }
    host_name:
        /*
         * the hostname production as-is is a parser nightmare.
         * simplify it to 
         * hostname = *( domainlabel "." ) domainlabel [ "." ]
         * and just make sure the last label starts with a non numeric char.
         */
        if (!IS_ALPHANUM(*cur))
            return(6);
        while (IS_ALPHANUM(*cur)) {
            while ((IS_ALPHANUM(*cur)) || (*cur == '-')) cur++;
    	if (*cur == '.')
    	    cur++;
        }
        tmp = cur;
        tmp--;
        while (IS_ALPHANUM(*tmp) && (*tmp != '.') && (tmp >= host)) tmp--;
        tmp++;
        if (!IS_ALPHA(*tmp))
            return(7);
        if (uri != NULL) {
    	if (uri->authority != NULL) xmlFree(uri->authority);
    	uri->authority = NULL;
    	if (uri->server != NULL) xmlFree(uri->server);
    	uri->server = xmlURIUnescapeString(host, cur - host, NULL);
        }
    
    host_done:
    
        /*
         * finish by checking for a port presence.
         */
        if (*cur == ':') {
            cur++;
    	if (IS_DIGIT(*cur)) {
    	    if (uri != NULL)
    	        uri->port = 0;
    	    while (IS_DIGIT(*cur)) {
    	        if (uri != NULL)
    		    uri->port = uri->port * 10 + (*cur - '0');
    		cur++;
    	    }
    	}
        }
        *str = cur;
        return(0);
    }	
    
    /**
     * xmlParseURIRelSegment:
     * @uri:  pointer to an URI structure
     * @str:  pointer to the string to analyze
     *
     * Parse an URI relative segment
     * 
     * rel_segment = 1*( unreserved | escaped | ";" | "@" | "&" | "=" |
     *                          "+" | "$" | "," )
     *
     * Returns 0 or the error code
     */
    int
    xmlParseURIRelSegment(xmlURIPtr uri, const char **str) {
        const char *cur;
    
        if (str == NULL)
    	return(-1);
        
        cur = *str;
        if (!IS_SEGMENT(cur)) {
    	return(3);
        }
        NEXT(cur);
        while (IS_SEGMENT(cur)) NEXT(cur);
        if (uri != NULL) {
    	if (uri->path != NULL) xmlFree(uri->path);
    	uri->path = xmlURIUnescapeString(*str, cur - *str, NULL);
        }
        *str = cur;
        return(0);
    }
    
    /**
     * xmlParseURIPathSegments:
     * @uri:  pointer to an URI structure
     * @str:  pointer to the string to analyze
     * @slash:  should we add a leading slash
     *
     * Parse an URI set of path segments
     * 
     * path_segments = segment *( "/" segment )
     * segment       = *pchar *( ";" param )
     * param         = *pchar
     *
     * Returns 0 or the error code
     */
    int
    xmlParseURIPathSegments(xmlURIPtr uri, const char **str, int slash) {
        const char *cur;
    
        if (str == NULL)
    	return(-1);
        
        cur = *str;
    
        do {
    	while (IS_PCHAR(cur)) NEXT(cur);
    	if (*cur == ';') {
    	    cur++;
    	    while (IS_PCHAR(cur)) NEXT(cur);
    	}
    	if (*cur != '/') break;
    	cur++;
        } while (1);
        if (uri != NULL) {
    	int len, len2 = 0;
    	char *path;
    
    	/*
    	 * Concat the set of path segments to the current path
    	 */
    	len = cur - *str;
    	if (slash)
    	    len++;
    
    	if (uri->path != NULL) {
    	    len2 = strlen(uri->path);
    	    len += len2;
    	}
            path = (char *) xmlMalloc(len + 1);
    	if (path == NULL) {
    	    xmlGenericError(xmlGenericErrorContext,
    		    "xmlParseURIPathSegments: out of memory\n");
    	    *str = cur;
    	    return(-1);
    	}
    	if (uri->path != NULL)
    	    memcpy(path, uri->path, len2);
    	if (slash) {
    	    path[len2] = '/';
    	    len2++;
    	}
    	path[len2] = 0;
    	if (cur - *str > 0)
    	    xmlURIUnescapeString(*str, cur - *str, &path[len2]);
    	if (uri->path != NULL)
    	    xmlFree(uri->path);
    	uri->path = path;
        }
        *str = cur;
        return(0);
    }
    
    /**
     * xmlParseURIAuthority:
     * @uri:  pointer to an URI structure
     * @str:  pointer to the string to analyze
     *
     * Parse the authority part of an URI.
     * 
     * authority = server | reg_name
     * server    = [ [ userinfo "@" ] hostport ]
     * reg_name  = 1*( unreserved | escaped | "$" | "," | ";" | ":" |
     *                        "@" | "&" | "=" | "+" )
     *
     * Note : this is completely ambiguous since reg_name is allowed to
     *        use the full set of chars in use by server:
     *
     *        3.2.1. Registry-based Naming Authority
     *
     *        The structure of a registry-based naming authority is specific
     *        to the URI scheme, but constrained to the allowed characters
     *        for an authority component.
     *
     * Returns 0 or the error code
     */
    int
    xmlParseURIAuthority(xmlURIPtr uri, const char **str) {
        const char *cur;
        int ret;
    
        if (str == NULL)
    	return(-1);
        
        cur = *str;
    
        /*
         * try first to parse it as a server string.
         */
        ret = xmlParseURIServer(uri, str);
        if (ret == 0)
            return(0);
    
        /*
         * failed, fallback to reg_name
         */
        if (!IS_REG_NAME(cur)) {
    	return(5);
        }
        NEXT(cur);
        while (IS_REG_NAME(cur)) NEXT(cur);
        if (uri != NULL) {
    	if (uri->server != NULL) xmlFree(uri->server);
    	uri->server = NULL;
    	if (uri->user != NULL) xmlFree(uri->user);
    	uri->user = NULL;
    	if (uri->authority != NULL) xmlFree(uri->authority);
    	uri->authority = xmlURIUnescapeString(*str, cur - *str, NULL);
        }
        *str = cur;
        return(0);
    }
    
    /**
     * xmlParseURIHierPart:
     * @uri:  pointer to an URI structure
     * @str:  pointer to the string to analyze
     *
     * Parse an URI hirarchical part
     * 
     * hier_part = ( net_path | abs_path ) [ "?" query ]
     * abs_path = "/"  path_segments
     * net_path = "//" authority [ abs_path ]
     *
     * Returns 0 or the error code
     */
    int
    xmlParseURIHierPart(xmlURIPtr uri, const char **str) {
        int ret;
        const char *cur;
    
        if (str == NULL)
    	return(-1);
        
        cur = *str;
    
        if ((cur[0] == '/') && (cur[1] == '/')) {
    	cur += 2;
    	ret = xmlParseURIAuthority(uri, &cur);
    	if (ret != 0)
    	    return(ret);
    	if (cur[0] == '/') {
    	    cur++;
    	    ret = xmlParseURIPathSegments(uri, &cur, 1);
    	}
        } else if (cur[0] == '/') {
    	cur++;
    	ret = xmlParseURIPathSegments(uri, &cur, 1);
        } else {
    	return(4);
        }
        if (ret != 0)
    	return(ret);
        if (*cur == '?') {
    	cur++;
    	ret = xmlParseURIQuery(uri, &cur);
    	if (ret != 0)
    	    return(ret);
        }
        *str = cur;
        return(0);
    }
    
    /**
     * xmlParseAbsoluteURI:
     * @uri:  pointer to an URI structure
     * @str:  pointer to the string to analyze
     *
     * Parse an URI reference string and fills in the appropriate fields
     * of the @uri structure
     * 
     * absoluteURI   = scheme ":" ( hier_part | opaque_part )
     *
     * Returns 0 or the error code
     */
    int
    xmlParseAbsoluteURI(xmlURIPtr uri, const char **str) {
        int ret;
    
        if (str == NULL)
    	return(-1);
        
        ret = xmlParseURIScheme(uri, str);
        if (ret != 0) return(ret);
        if (**str != ':')
    	return(1);
        (*str)++;
        if (**str == '/')
    	return(xmlParseURIHierPart(uri, str));
        return(xmlParseURIOpaquePart(uri, str));
    }
    
    /**
     * xmlParseRelativeURI:
     * @uri:  pointer to an URI structure
     * @str:  pointer to the string to analyze
     *
     * Parse an relative URI string and fills in the appropriate fields
     * of the @uri structure
     * 
     * relativeURI = ( net_path | abs_path | rel_path ) [ "?" query ]
     * abs_path = "/"  path_segments
     * net_path = "//" authority [ abs_path ]
     * rel_path = rel_segment [ abs_path ]
     *
     * Returns 0 or the error code
     */
    int
    xmlParseRelativeURI(xmlURIPtr uri, const char **str) {
        int ret = 0;
        const char *cur;
    
        if (str == NULL)
    	return(-1);
        
        cur = *str;
        if ((cur[0] == '/') && (cur[1] == '/')) {
    	cur += 2;
    	ret = xmlParseURIAuthority(uri, &cur);
    	if (ret != 0)
    	    return(ret);
    	if (cur[0] == '/') {
    	    cur++;
    	    ret = xmlParseURIPathSegments(uri, &cur, 1);
    	}
        } else if (cur[0] == '/') {
    	cur++;
    	ret = xmlParseURIPathSegments(uri, &cur, 1);
        } else if (cur[0] != '#' && cur[0] != '?') {
    	ret = xmlParseURIRelSegment(uri, &cur);
    	if (ret != 0)
    	    return(ret);
    	if (cur[0] == '/') {
    	    cur++;
    	    ret = xmlParseURIPathSegments(uri, &cur, 1);
    	}
        }
        if (ret != 0)
    	return(ret);
        if (*cur == '?') {
    	cur++;
    	ret = xmlParseURIQuery(uri, &cur);
    	if (ret != 0)
    	    return(ret);
        }
        *str = cur;
        return(ret);
    }
    
    /**
     * xmlParseURIReference:
     * @uri:  pointer to an URI structure
     * @str:  the string to analyze
     *
     * Parse an URI reference string and fills in the appropriate fields
     * of the @uri structure
     * 
     * URI-reference = [ absoluteURI | relativeURI ] [ "#" fragment ]
     *
     * Returns 0 or the error code
     */
    int
    xmlParseURIReference(xmlURIPtr uri, const char *str) {
        int ret;
        const char *tmp = str;
    
        if (str == NULL)
    	return(-1);
        xmlCleanURI(uri);
    
        /*
         * Try first to parse aboslute refs, then fallback to relative if
         * it fails.
         */
        ret = xmlParseAbsoluteURI(uri, &str);
        if (ret != 0) {
    	xmlCleanURI(uri);
    	str = tmp;
            ret = xmlParseRelativeURI(uri, &str);
        }
        if (ret != 0) {
    	xmlCleanURI(uri);
    	return(ret);
        }
    
        if (*str == '#') {
    	str++;
    	ret = xmlParseURIFragment(uri, &str);
    	if (ret != 0) return(ret);
        }
        if (*str != 0) {
    	xmlCleanURI(uri);
    	return(1);
        }
        return(0);
    }
    
    /**
     * xmlParseURI:
     * @str:  the URI string to analyze
     *
     * Parse an URI 
     * 
     * URI-reference = [ absoluteURI | relativeURI ] [ "#" fragment ]
     *
     * Returns a newly build xmlURIPtr or NULL in case of error
     */
    xmlURIPtr
    xmlParseURI(const char *str) {
        xmlURIPtr uri;
        int ret;
    
        if (str == NULL)
    	return(NULL);
        uri = xmlCreateURI();
        if (uri != NULL) {
    	ret = xmlParseURIReference(uri, str);
            if (ret) {
    	    xmlFreeURI(uri);
    	    return(NULL);
    	}
        }
        return(uri);
    }
    
    /************************************************************************
     *									*
     *			Public functions				*
     *									*
     ************************************************************************/
    
    /**
     * xmlBuildURI:
     * @URI:  the URI instance found in the document
     * @base:  the base value
     *
     * Computes he final URI of the reference done by checking that
     * the given URI is valid, and building the final URI using the
     * base URI. This is processed according to section 5.2 of the 
     * RFC 2396
     *
     * 5.2. Resolving Relative References to Absolute Form
     *
     * Returns a new URI string (to be freed by the caller) or NULL in case
     *         of error.
     */
    xmlChar *
    xmlBuildURI(const xmlChar *URI, const xmlChar *base) {
        xmlChar *val = NULL;
        int ret, len, index, cur, out;
        xmlURIPtr ref = NULL;
        xmlURIPtr bas = NULL;
        xmlURIPtr res = NULL;
    
        /*
         * 1) The URI reference is parsed into the potential four components and
         *    fragment identifier, as described in Section 4.3.
         *
         *    NOTE that a completely empty URI is treated by modern browsers
         *    as a reference to "." rather than as a synonym for the current
         *    URI.  Should we do that here?
         */
        if (URI == NULL) 
    	ret = -1;
        else {
    	if (*URI) {
    	    ref = xmlCreateURI();
    	    if (ref == NULL)
    		goto done;
    	    ret = xmlParseURIReference(ref, (const char *) URI);
    	}
    	else
    	    ret = 0;
        }
        if (ret != 0)
    	goto done;
        if (base == NULL)
    	ret = -1;
        else {
    	bas = xmlCreateURI();
    	if (bas == NULL)
    	    goto done;
    	ret = xmlParseURIReference(bas, (const char *) base);
        }
        if (ret != 0) {
    	if (ref)
    	    val = xmlSaveUri(ref);
    	goto done;
        }
        if (ref == NULL) {
    	/*
    	 * the base fragment must be ignored
    	 */
    	if (bas->fragment != NULL) {
    	    xmlFree(bas->fragment);
    	    bas->fragment = NULL;
    	}
    	val = xmlSaveUri(bas);
    	goto done;
        }
    
        /*
         * 2) If the path component is empty and the scheme, authority, and
         *    query components are undefined, then it is a reference to the
         *    current document and we are done.  Otherwise, the reference URI's
         *    query and fragment components are defined as found (or not found)
         *    within the URI reference and not inherited from the base URI.
         *
         *    NOTE that in modern browsers, the parsing differs from the above
         *    in the following aspect:  the query component is allowed to be
         *    defined while still treating this as a reference to the current
         *    document.
         */
        res = xmlCreateURI();
        if (res == NULL)
    	goto done;
        if ((ref->scheme == NULL) && (ref->path == NULL) &&
    	((ref->authority == NULL) && (ref->server == NULL))) {
    	if (bas->scheme != NULL)
    	    res->scheme = xmlMemStrdup(bas->scheme);
    	if (bas->authority != NULL)
    	    res->authority = xmlMemStrdup(bas->authority);
    	else if (bas->server != NULL) {
    	    res->server = xmlMemStrdup(bas->server);
    	    if (bas->user != NULL)
    		res->user = xmlMemStrdup(bas->user);
    	    res->port = bas->port;		
    	}
    	if (bas->path != NULL)
    	    res->path = xmlMemStrdup(bas->path);
    	if (ref->query != NULL)
    	    res->query = xmlMemStrdup(ref->query);
    	else if (bas->query != NULL)
    	    res->query = xmlMemStrdup(bas->query);
    	if (ref->fragment != NULL)
    	    res->fragment = xmlMemStrdup(ref->fragment);
    	goto step_7;
        }
     
        if (ref->query != NULL)
    	res->query = xmlMemStrdup(ref->query);
        if (ref->fragment != NULL)
    	res->fragment = xmlMemStrdup(ref->fragment);
    
        /*
         * 3) If the scheme component is defined, indicating that the reference
         *    starts with a scheme name, then the reference is interpreted as an
         *    absolute URI and we are done.  Otherwise, the reference URI's
         *    scheme is inherited from the base URI's scheme component.
         */
        if (ref->scheme != NULL) {
    	val = xmlSaveUri(ref);
    	goto done;
        }
        if (bas->scheme != NULL)
    	res->scheme = xmlMemStrdup(bas->scheme);
    
        /*
         * 4) If the authority component is defined, then the reference is a
         *    network-path and we skip to step 7.  Otherwise, the reference
         *    URI's authority is inherited from the base URI's authority
         *    component, which will also be undefined if the URI scheme does not
         *    use an authority component.
         */
        if ((ref->authority != NULL) || (ref->server != NULL)) {
    	if (ref->authority != NULL)
    	    res->authority = xmlMemStrdup(ref->authority);
    	else {
    	    res->server = xmlMemStrdup(ref->server);
    	    if (ref->user != NULL)
    		res->user = xmlMemStrdup(ref->user);
                res->port = ref->port;		
    	}
    	if (ref->path != NULL)
    	    res->path = xmlMemStrdup(ref->path);
    	goto step_7;
        }
        if (bas->authority != NULL)
    	res->authority = xmlMemStrdup(bas->authority);
        else if (bas->server != NULL) {
    	res->server = xmlMemStrdup(bas->server);
    	if (bas->user != NULL)
    	    res->user = xmlMemStrdup(bas->user);
    	res->port = bas->port;		
        }
    
        /*
         * 5) If the path component begins with a slash character ("/"), then
         *    the reference is an absolute-path and we skip to step 7.
         */
        if ((ref->path != NULL) && (ref->path[0] == '/')) {
    	res->path = xmlMemStrdup(ref->path);
    	goto step_7;
        }
    
    
        /*
         * 6) If this step is reached, then we are resolving a relative-path
         *    reference.  The relative path needs to be merged with the base
         *    URI's path.  Although there are many ways to do this, we will
         *    describe a simple method using a separate string buffer.
         *
         * Allocate a buffer large enough for the result string.
         */
        len = 2; /* extra / and 0 */
        if (ref->path != NULL)
    	len += strlen(ref->path);
        if (bas->path != NULL)
    	len += strlen(bas->path);
        res->path = (char *) xmlMalloc(len);
        if (res->path == NULL) {
    	xmlGenericError(xmlGenericErrorContext,
    		"xmlBuildURI: out of memory\n");
    	goto done;
        }
        res->path[0] = 0;
    
        /*
         * a) All but the last segment of the base URI's path component is
         *    copied to the buffer.  In other words, any characters after the
         *    last (right-most) slash character, if any, are excluded.
         */
        cur = 0;
        out = 0;
        if (bas->path != NULL) {
    	while (bas->path[cur] != 0) {
    	    while ((bas->path[cur] != 0) && (bas->path[cur] != '/'))
    		cur++;
    	    if (bas->path[cur] == 0)
    		break;
    
    	    cur++;
    	    while (out < cur) {
    		res->path[out] = bas->path[out];
    		out++;
    	    }
    	}
        }
        res->path[out] = 0;
    
        /*
         * b) The reference's path component is appended to the buffer
         *    string.
         */
        if (ref->path != NULL && ref->path[0] != 0) {
    	index = 0;
    	/*
    	 * Ensure the path includes a '/'
    	 */
    	if ((out == 0) && (bas->server != NULL))
    	    res->path[out++] = '/';
    	while (ref->path[index] != 0) {
    	    res->path[out++] = ref->path[index++];
    	}
        }
        res->path[out] = 0;
    
        /*
         * Steps c) to h) are really path normalization steps
         */
        xmlNormalizeURIPath(res->path);
    
    step_7:
    
        /*
         * 7) The resulting URI components, including any inherited from the
         *    base URI, are recombined to give the absolute form of the URI
         *    reference.
         */
        val = xmlSaveUri(res);
    
    done:
        if (ref != NULL)
    	xmlFreeURI(ref);
        if (bas != NULL)
    	xmlFreeURI(bas);
        if (res != NULL)
    	xmlFreeURI(res);
        return(val);
    }