5 files changed, 53 insertions, 12 deletions

diff --git a/include/opkele/data.h b/include/opkele/data.h
index d0b0516..904b5ae 100644
--- a/include/opkele/data.h
+++ b/include/opkele/data.h
@@ -1,18 +1,20 @@
 #ifndef __OPKELE_DATA_H
 #define __OPKELE_DATA_H
 
 /**
  * @brief the main opkele namespace
  */
 namespace opkele {
 
     /**
      * @brief internal data opkele namespace
      */
     namespace data {
         extern const char *_default_p;
         extern const char *_default_g;
+        extern const char *_iname_leaders;
+        extern const char *_whitespace_chars;
     }
 }
 
 #endif /* __OPKELE_DATA_H */
diff --git a/include/opkele/util.h b/include/opkele/util.h
index 60955e1..fd974a1 100644
--- a/include/opkele/util.h
+++ b/include/opkele/util.h
@@ -23,92 +23,94 @@ namespace opkele {
          */
         string time_to_w3c(time_t t);
         /**
          * Convert W3C time representation to  internal time_t
          * @param w w3c representation
          * @return converted time
          * @throw failed_conversion in case of error
          */
         time_t w3c_to_time(const string& w);
 
         /**
          * Encode string to the representation suitable for using in URL.
          * @param str string to encode
          * @return encoded string
          * @throw failed_conversion in case of failure
          */
         string url_encode(const string& str);
 
         /**
          * Make string suitable for using as x(ht)ml attribute.
          * @param str string to escape
          * @return escaped string
          */
         string attr_escape(const string& str);
 
         /**
          * Convert number to string
          * @param l number
          * @return string representation
          * @throw failed_conversion in case of failure
          */
         string long_to_string(long l);
         /**
          * Convert string to number
          * @param s string, containing the number
          * @return the number
          * @throw failed_conversion in case of failure
          */
         long string_to_long(const string& s);
 
         /**
          * Encode binary data using base64.
          * @param data pointer to binary data
          * @param length length of data
          * @return encoded data
          */
         string encode_base64(const void *data,size_t length);
         /**
          * Decode binary data from base64 representation.
          * @param data base64-encoded data
          * @param rv container for decoded binary
          */
         void decode_base64(const string& data,vector<unsigned char>& rv);
 
         /**
          * Normalize http(s) URI according to RFC3986, section 6. URI is
          * expected to have scheme: in front of it.
          * @param uri URI
          * @return normalized URI
          * @throw not_implemented in case of non-httpi(s) URI
          * @throw bad_input in case of malformed URI
          */
         string rfc_3986_normalize_uri(const string& uri);
 
+        string normalize_identifier(const string& usi,bool strip_fragment);
+
         /**
          * Match URI against realm
          * @param uri URI to match
          * @param realm realm to match against
          * @return true if URI matches realm
          */
         bool uri_matches_realm(const string& uri,const string& realm);
 
         /**
          * Strip fragment part from URI
          * @param uri input/output parameter containing the URI
          * @return reference to uri
          */
         string& strip_uri_fragment_part(string& uri);
 
         /**
          * Calculate signature and encode it using base64
          * @param assoc association being used for signing
          * @param om openid message
          * @return base64 representation of the signature
          */
         string base64_signature(const assoc_t& assoc,const basic_openid_message& om);
 
     }
 
 }
 
 #endif /* __OPKELE_UTIL_H */
diff --git a/lib/data.cc b/lib/data.cc
index c040430..f71788f 100644
--- a/lib/data.cc
+++ b/lib/data.cc
@@ -1,11 +1,14 @@
 #include <opkele/data.h>
 
 namespace opkele {
 
     namespace data {
 
         const char *_default_p = "155172898181473697471232257763715539915724801966915404479707795314057629378541917580651227423698188993727816152646631438561595825688188889951272158842675419950341258706556549803580104870537681476726513255747040765857479291291572334510643245094715007229621094194349783925984760375594985848253359305585439638443";
         const char *_default_g = "2";
 
+        const char *_iname_leaders = "=@+$!(";
+        const char *_whitespace_chars = " \t\r\n";
+
     }
 }
diff --git a/lib/discovery.cc b/lib/discovery.cc
index b7f2db6..5913ad4 100644
--- a/lib/discovery.cc
+++ b/lib/discovery.cc
@@ -1,206 +1,205 @@
 #include <list>
 #include <opkele/curl.h>
 #include <opkele/expat.h>
 #include <opkele/uris.h>
 #include <opkele/discovery.h>
 #include <opkele/exception.h>
 #include <opkele/util.h>
 #include <opkele/tidy.h>
+#include <opkele/data.h>
 #include <opkele/debug.h>
 
 #include "config.h"
 
 #define XRDS_HEADER "X-XRDS-Location"
 #define CT_HEADER "Content-Type"
 
 namespace opkele {
     using std::list;
     using xrd::XRD_t;
     using xrd::service_t;
 
     /* TODO: the whole discovery thing needs cleanup and optimization due to
      * many changes of concept. */
 
-    static const char *whitespace = " \t\r\n";
-    static const char *i_leaders = "=@+$!(";
     static const size_t max_html = 16384;
 
     static const struct service_type_t {
         const char *uri;
         const char *forceid;
     } op_service_types[] = {
         { STURI_OPENID20_OP, IDURI_SELECT20 },
         { STURI_OPENID20, 0 },
         { STURI_OPENID11, 0 },
         { STURI_OPENID10, 0 }
     };
     enum {
         st_index_1 = 2, st_index_2 = 1
     };
 
 
     static inline bool is_qelement(const XML_Char *n,const char *qen) {
         return !strcasecmp(n,qen);
     }
     static inline bool is_element(const XML_Char *n,const char *en) {
         if(!strcasecmp(n,en)) return true;
         int nl = strlen(n), enl = strlen(en);
         if( (nl>=(enl+1)) && n[nl-enl-1]=='\t'
                 && !strcasecmp(&n[nl-enl],en) )
             return true;
         return false;
     }
 
     static long element_priority(const XML_Char **a) {
         for(;*a;++a)
             if(!strcasecmp(*(a++),"priority")) {
                 long rv;
                 return (sscanf(*a,"%ld",&rv)==1)?rv:-1;
             }
         return -1;
     }
     /* TODO: ideally all attributes should be
      * retrieved in one run */
     static const char *element_attr(const XML_Char **a, const char *at) {
         for(;*a;++a)
             if(!strcasecmp(*(a++),at)) {
                 return *a;
             }
         return 0;
     }
 
     class idigger_t : public util::curl_t, public util::expat_t {
         public:
             string xri_proxy;
 
             enum {
                 xmode_html = 1, xmode_xrd = 2, xmode_cid = 4,
                 xmode_noredirs = 8
             };
             int xmode;
 
             string xrds_location;
             string http_content_type;
             service_t html_openid1;
             service_t html_openid2;
             string cdata_buf;
             long status_code;
             string status_string;
 
             typedef list<string> pt_stack_t;
             pt_stack_t pt_stack;
             int skipping;
             bool parser_choked;
             string save_html;
 
             XRD_t *xrd;
             service_t *xrd_service;
             string* cdata;
 
             idigger_t()
                 : util::curl_t(easy_init()),
                 util::expat_t(0),
                 xri_proxy(XRI_PROXY_URL) {
                     CURLcode r;
                     (r=misc_sets())
                         || (r=set_write())
                         || (r=set_header())
                         ;
                     if(r)
                         throw exception_curl(OPKELE_CP_ "failed to set curly options",r);
                 }
             ~idigger_t() throw() { }
 
             void yadiscover(endpoint_discovery_iterator oi,const string& yurl,const char **types,bool redirs) {
                 idiscovery_t idis;
                 idis.xri_identity = false;
                 discover_at(idis,yurl,xmode_html|xmode_xrd|(redirs?0:xmode_noredirs));
                 if(!xrds_location.empty()) {
                     idis.clear();
                     discover_at(idis,xrds_location,xmode_xrd);
                 }
                 idis.normalized_id = idis.canonicalized_id = yurl;
                 service_type_t st;
                 for(st.uri=*types;*types;st.uri=*(++types))
                     queue_endpoints(oi,idis,&st);
             }
 
             string discover(endpoint_discovery_iterator& oi,const string& identity) {
                 string rv;
                 idiscovery_t idis;
-                string::size_type fsc = identity.find_first_not_of(whitespace);
+                string::size_type fsc = identity.find_first_not_of(data::_whitespace_chars);
                 if(fsc==string::npos)
                     throw bad_input(OPKELE_CP_ "whitespace-only identity");
-                string::size_type lsc = identity.find_last_not_of(whitespace);
+                string::size_type lsc = identity.find_last_not_of(data::_whitespace_chars);
                 assert(lsc!=string::npos);
                 if(!strncasecmp(identity.c_str()+fsc,"xri://",sizeof("xri://")-1))
                     fsc += sizeof("xri://")-1;
                 if((fsc+1)>=lsc)
                     throw bad_input(OPKELE_CP_ "not a character of importance in identity");
                 string id(identity,fsc,lsc-fsc+1);
                 idis.clear();
-                if(strchr(i_leaders,id[0])) {
+                if(strchr(data::_iname_leaders,id[0])) {
                     /* TODO: further normalize xri identity? Like folding case
                      * or whatever... */
                     rv = id;
                     set<string> cids;
                     for(const struct service_type_t *st=op_service_types;
                             st<&op_service_types[sizeof(op_service_types)/sizeof(*op_service_types)];++st) {
                         idis.clear();
                         discover_at( idis,
                                 xri_proxy + util::url_encode(id)+
                                 "?_xrd_t="+util::url_encode(st->uri)+
                                 "&_xrd_r=application/xrd%2Bxml"
                                 ";sep=true;refs=true",
                                 xmode_xrd );
                         if(status_code==241) continue;
                         if(status_code!=100)
                             throw failed_xri_resolution(OPKELE_CP_
                                     "XRI resolution failed with '"+status_string+"' message"
                                     ", while looking for SEP with type '"+st->uri+"'", status_code);
                         if(idis.xrd.canonical_ids.empty())
                             throw opkele::failed_discovery(OPKELE_CP_ "No CanonicalID for XRI identity found");
                         string cid = idis.xrd.canonical_ids.begin()->second;
                         if(cids.find(cid)==cids.end()) {
                             cids.insert(cid);
                             idis.clear();
                             discover_at( idis,
                                     xri_proxy + util::url_encode(id)+
                                     "?_xrd_t="+util::url_encode(st->uri)+
                                     "&_xrd_r=application/xrd%2Bxml"
                                     ";sep=true;refs=true",
                                     xmode_xrd );
                             if(status_code==241) continue;
                             if(status_code!=100)
                                 throw failed_xri_resolution(OPKELE_CP_
                                         "XRI resolution failed with '"+status_string+"' message"
                                         ", while looking for SEP with type '"+st->uri+"'"
                                         " on canonical id", status_code);
                         }
                         idis.canonicalized_id = cid;
                         idis.normalized_id = rv; idis.xri_identity = true;
                         queue_endpoints(oi,idis,st);
                     }
                 }else{
                     idis.xri_identity = false;
                     if(id.find("://")==string::npos)
                         id.insert(0,"http://");
                     string::size_type fp = id.find('#');
                     if(fp!=string::npos) {
                         string::size_type qp = id.find('?');
                         if(qp==string::npos || qp<fp)
                             id.erase(fp);
                         else if(qp>fp)
                             id.erase(fp,qp-fp);
                     }
                     rv = idis.normalized_id = util::rfc_3986_normalize_uri(id);
                     discover_at(idis,id,xmode_html|xmode_xrd);
                     const char * eu = 0;
                     CURLcode r = easy_getinfo(CURLINFO_EFFECTIVE_URL,&eu);
                     if(r)
                         throw exception_curl(OPKELE_CP_ "failed to get CURLINFO_EFFECTIVE_URL",r);
                     string cid = util::strip_uri_fragment_part( idis.canonicalized_id = util::rfc_3986_normalize_uri(eu) );
                     if(xrds_location.empty()) {
                         html2xrd(oi,idis);
                     }else{
                         idis.clear();
@@ -434,135 +433,135 @@ namespace opkele {
                         html_start_element(n,a);
                     }else{
                         skipping = 1;
                     }
                 }
             }
             void end_element(const XML_Char *n) {
                 if(skipping<0) return;
                 if(skipping) {
                     --skipping; return;
                 }
                 if(is_qelement(n,NSURI_XRD "\tType")) {
                     assert(xrd); assert(xrd_service); assert(cdata==&cdata_buf);
                     xrd_service->types.insert(cdata_buf);
                 }else if(is_qelement(n,NSURI_XRD "\tService")) {
                     assert(xrd); assert(xrd_service);
                     assert(!pt_stack.empty());
                     assert(pt_stack.back()==(NSURI_XRD "\tService"));
                     pt_stack.pop_back();
                     xrd_service = 0;
                 }else if(is_qelement(n,NSURI_XRD "\tStatus")) {
                     assert(xrd);
                     if(is_qelement(pt_stack.back().c_str(),n)) {
                         assert(cdata==&status_string);
                         pt_stack.pop_back();
                         if(status_code!=100)
                             skipping = -1;
                     }
                 }else if(is_qelement(n,NSURI_XRD "\tExpires")) {
                     assert(xrd);
                     xrd->expires = util::w3c_to_time(cdata_buf);
                 }else if((xmode&xmode_html) && is_element(n,"head")) {
                     skipping = -1;
                 }
                 cdata = 0;
             }
             void character_data(const XML_Char *s,int l) {
                 if(skipping) return;
                 if(cdata) cdata->append(s,l);
             }
 
             void html_start_element(const XML_Char *n,const XML_Char **a) {
                 if(is_element(n,"meta")) {
                     bool heq = false;
                     string l;
                     for(;*a;a+=2) {
                         if(!( strcasecmp(a[0],"http-equiv")
                                 || strcasecmp(a[1],XRDS_HEADER) ))
                             heq = true;
                         else if(!strcasecmp(a[0],"content"))
                             l.assign(a[1]);
                     }
                     if(heq)
                         xrds_location = l;
                 }else if(is_element(n,"link")) {
                     string rels;
                     string href;
                     for(;*a;a+=2) {
                         if( !strcasecmp(a[0],"rel") ) {
                             rels.assign(a[1]);
                         }else if( !strcasecmp(a[0],"href") ) {
                             const char *ns = a[1];
                             for(;*ns && isspace(*ns);++ns);
                             href.assign(ns);
-                            string::size_type lns=href.find_last_not_of(whitespace);
+                            string::size_type lns=href.find_last_not_of(data::_whitespace_chars);
                             href.erase(lns+1);
                         }
                     }
-                    for(string::size_type ns=rels.find_first_not_of(whitespace);
-                            ns!=string::npos; ns=rels.find_first_not_of(whitespace,ns)) {
-                        string::size_type s = rels.find_first_of(whitespace,ns);
+                    for(string::size_type ns=rels.find_first_not_of(data::_whitespace_chars);
+                            ns!=string::npos; ns=rels.find_first_not_of(data::_whitespace_chars,ns)) {
+                        string::size_type s = rels.find_first_of(data::_whitespace_chars,ns);
                         string rel;
                         if(s==string::npos) {
                             rel.assign(rels,ns,string::npos);
                             ns = string::npos;
                         }else{
                             rel.assign(rels,ns,s-ns);
                             ns = s;
                         }
                         if(rel=="openid.server")
                             html_openid1.uris.add(-1,xrd::uri_t(href));
                         else if(rel=="openid.delegate")
                             html_openid1.local_ids.add(-1,href);
                         else if(rel=="openid2.provider")
                             html_openid2.uris.add(-1,xrd::uri_t(href));
                         else if(rel=="openid2.local_id")
                             html_openid2.local_ids.add(-1,href);
                     }
                 }else if(is_element(n,"body")) {
                     skipping = -1;
                 }
             }
 
             void queue_endpoints(endpoint_discovery_iterator& oi,
                     const idiscovery_t &id,
                     const service_type_t *st) {
                 openid_endpoint_t ep;
                 ep.claimed_id = id.canonicalized_id;
                 for(xrd::services_t::const_iterator isvc=id.xrd.services.begin();
                         isvc!=id.xrd.services.end(); ++isvc) {
                     const xrd::service_t svc = isvc->second;
                     if(svc.types.find(st->uri)==svc.types.end()) continue;
                     for(xrd::uris_t::const_iterator iu=svc.uris.begin();iu!=svc.uris.end();++iu) {
                         ep.uri = iu->second.uri;
                         if(id.xri_identity) {
                             if(iu->second.append=="qxri") {
                                 ep.uri += id.normalized_id;
                             } /* TODO: else handle other append attribute values */
                         }
                         if(st->forceid) {
                             ep.local_id = ep.claimed_id = st->forceid;
                             *(oi++) = ep;
                         }else{
                             if(svc.local_ids.empty()) {
                                 ep.local_id = ep.claimed_id;
                                 *(oi++) = ep;
                             }else{
                                 for(xrd::local_ids_t::const_iterator ilid=svc.local_ids.begin();
                                         ilid!=svc.local_ids.end(); ++ilid) {
                                     ep.local_id = ilid->second;
                                     *(oi++) = ep;
                                 }
                             }
                         }
                     }
                 }
             }
 
     };
 
     string idiscover(endpoint_discovery_iterator oi,const string& identity) {
         idigger_t idigger;
         return idigger.discover(oi,identity);
     }
 
diff --git a/lib/util.cc b/lib/util.cc
index bb8a2e8..29e6738 100644
--- a/lib/util.cc
+++ b/lib/util.cc
@@ -1,79 +1,80 @@
 #include <errno.h>
 #include <cassert>
 #include <cctype>
 #include <cstring>
 #include <vector>
 #include <string>
 #include <stack>
 #include <algorithm>
 #include <openssl/bio.h>
 #include <openssl/evp.h>
 #include <openssl/sha.h>
 #include <openssl/hmac.h>
 #include <curl/curl.h>
 #include <opkele/util.h>
 #include <opkele/exception.h>
+#include <opkele/data.h>
 #include <opkele/debug.h>
 
 #include <config.h>
 #ifdef HAVE_DEMANGLE
 # include <cxxabi.h>
 #endif
 
 namespace opkele {
     using namespace std;
 
     namespace util {
 
         /*
          * base64
          */
         string encode_base64(const void *data,size_t length) {
             BIO *b64 = 0, *bmem = 0;
             try {
                 b64 = BIO_new(BIO_f_base64());
                 if(!b64)
                     throw exception_openssl(OPKELE_CP_ "failed to BIO_new() base64 encoder");
                 BIO_set_flags(b64,BIO_FLAGS_BASE64_NO_NL);
                 bmem = BIO_new(BIO_s_mem());
                 BIO_set_flags(b64,BIO_CLOSE);
                 if(!bmem)
                     throw exception_openssl(OPKELE_CP_ "failed to BIO_new() memory buffer");
                 BIO_push(b64,bmem);
                 if(((size_t)BIO_write(b64,data,length))!=length)
                     throw exception_openssl(OPKELE_CP_ "failed to BIO_write()");
                 if(BIO_flush(b64)!=1)
                     throw exception_openssl(OPKELE_CP_ "failed to BIO_flush()");
                 char *rvd;
                 long rvl = BIO_get_mem_data(bmem,&rvd);
                 string rv(rvd,rvl);
                 BIO_free_all(b64);
                 return rv;
             }catch(...) {
                 if(b64) BIO_free_all(b64);
                 throw;
             }
         }
 
         void decode_base64(const string& data,vector<unsigned char>& rv) {
             BIO *b64 = 0, *bmem = 0;
             rv.clear();
             try {
                 bmem = BIO_new_mem_buf((void*)data.data(),data.size());
                 if(!bmem)
                     throw exception_openssl(OPKELE_CP_ "failed to BIO_new_mem_buf()");
                 b64 = BIO_new(BIO_f_base64());
                 if(!b64)
                     throw exception_openssl(OPKELE_CP_ "failed to BIO_new() base64 decoder");
                 BIO_set_flags(b64,BIO_FLAGS_BASE64_NO_NL);
                 BIO_push(b64,bmem);
                 unsigned char tmp[512];
                 size_t rb = 0;
                 while((rb=BIO_read(b64,tmp,sizeof(tmp)))>0)
                     rv.insert(rv.end(),tmp,&tmp[rb]);
                 BIO_free_all(b64);
             }catch(...) {
                 if(b64) BIO_free_all(b64);
                 throw;
             }
         }
@@ -150,141 +151,140 @@ namespace opkele {
                 throw failed_conversion(OPKELE_CP_ "failed to mktime()");
             return rv-timezone;
         }
 
         /*
          *
          */
 
         string url_encode(const string& str) {
             char * t = curl_escape(str.c_str(),str.length());
             if(!t)
                 throw failed_conversion(OPKELE_CP_ "failed to curl_escape()");
             string rv(t);
             curl_free(t);
             return rv;
         }
 
         string attr_escape(const string& str) {
             static const char *unsafechars = "<>&\n\"'";
             string rv;
             string::size_type p=0;
             while(true) {
                 string::size_type us = str.find_first_of(unsafechars,p);
                 if(us==string::npos) {
                     if(p!=str.length())
                         rv.append(str,p,str.length()-p);
                     return rv;
                 }
                 rv.append(str,p,us-p);
                 rv += "&#";
                 rv += long_to_string((long)str[us]);
                 rv += ';';
                 p = us+1;
             }
         }
 
         string long_to_string(long l) {
             char rv[32];
             int r=snprintf(rv,sizeof(rv),"%ld",l);
             if(r<0 || r>=(int)sizeof(rv))
                 throw failed_conversion(OPKELE_CP_ "failed to snprintf()");
             return rv;
         }
 
         long string_to_long(const string& s) {
             char *endptr = 0;
             long rv = strtol(s.c_str(),&endptr,10);
             if((!endptr) || endptr==s.c_str())
                 throw failed_conversion(OPKELE_CP_ "failed to strtol()");
             return rv;
         }
 
         /*
          * Normalize URL according to the rules, described in rfc 3986, section 6
          *
          * - uppercase hex triplets (e.g. %ab -> %AB)
          * - lowercase scheme and host
          * - decode %-encoded characters, specified as unreserved in rfc 3986, section 2.3,
          *   that is - [:alpha:][:digit:]._~-
          * - remove dot segments
          * - remove empty and default ports
          * - if there's no path component, add '/'
          */
          string rfc_3986_normalize_uri(const string& uri) {
-             static const char *whitespace = " \t\r\n";
              string rv;
-             string::size_type ns = uri.find_first_not_of(whitespace);
+             string::size_type ns = uri.find_first_not_of(data::_whitespace_chars);
              if(ns==string::npos)
                  throw bad_input(OPKELE_CP_ "Can't normalize empty URI");
              string::size_type colon = uri.find(':',ns);
              if(colon==string::npos)
                  throw bad_input(OPKELE_CP_ "No scheme specified in URI");
              transform(
                      uri.begin()+ns, uri.begin()+colon+1,
                      back_inserter(rv), ::tolower );
              bool s;
-             string::size_type ul = uri.find_last_not_of(whitespace)+1;
+             string::size_type ul = uri.find_last_not_of(data::_whitespace_chars)+1;
              if(ul <= (colon+3))
                  throw bad_input(OPKELE_CP_ "Unexpected end of URI being normalized encountered");
              if(uri[colon+1]!='/' || uri[colon+2]!='/')
                  throw bad_input(OPKELE_CP_ "Unexpected input in URI being normalized after scheme component");
              if(rv=="http:")
                  s = false;
              else if(rv=="https:")
                  s = true;
              else{
                  /* TODO: support more schemes.  e.g. xri. How do we normalize
                   * xri?
                   */
                  rv.append(uri,colon+1,ul-colon-1);
                  return rv;
              }
              rv += "//";
              string::size_type interesting = uri.find_first_of(":/#?",colon+3);
              if(interesting==string::npos) {
                  transform(
                          uri.begin()+colon+3,uri.begin()+ul,
                          back_inserter(rv), ::tolower );
                  rv += '/'; return rv;
              }
              transform(
                      uri.begin()+colon+3,uri.begin()+interesting,
                      back_inserter(rv), ::tolower );
              bool qf = false;
              char ic = uri[interesting];
              if(ic==':') {
                  string::size_type ni = uri.find_first_of("/#?%",interesting+1);
                  const char *nptr = uri.data()+interesting+1;
                  char *eptr = 0;
                  long port = strtol(nptr,&eptr,10);
                  if( (port>0) && (port<65535) && port!=(s?443:80) ) {
                      char tmp[8];
                      snprintf(tmp,sizeof(tmp),":%ld",port);
                      rv += tmp;
                  }
                  if(ni==string::npos) {
                      rv += '/'; return rv;
                  }
                  interesting = ni;
              }else if(ic!='/') {
                  rv += '/'; rv += ic;
                  qf = true;
                  ++interesting;
              }
              string::size_type n = interesting;
              char tmp[3] = { 0,0,0 };
              stack<string::size_type> psegs; psegs.push(rv.length());
              string pseg;
              for(;n<ul;) {
                  string::size_type unsafe = uri.find_first_of(qf?"%":"%/?#",n);
                  if(unsafe==string::npos) {
                      pseg.append(uri,n,ul-n-1); n = ul-1;
                  }else{
                      pseg.append(uri,n,unsafe-n);
                      n = unsafe;
                  }
                  char c = uri[n++];
                  if(c=='%') {
                      if((n+1)>=ul)
                          throw bad_input(OPKELE_CP_ "Unexpected end of URI encountered while parsing percent-encoded character");
                      tmp[0] = uri[n++];
@@ -369,67 +369,102 @@ namespace opkele {
                 if(pu==string::npos)
                     return false;
                 // TODO: check for overgeneralized realm
             }
             string::size_type lr = nrealm.length();
             string::size_type lu = nu.length();
             if( (lu-pu) < (lr-pr) )
                 return false;
             pair<const char*,const char*> mp = mismatch(
                     nrealm.c_str()+pr,nrealm.c_str()+lr,
                     nu.c_str()+pu);
             if( (*(mp.first-1))!='/'
                     && !strchr("/?#",*mp.second) )
                 return false;
             return true;
         }
 
         string abi_demangle(const char *mn) {
 #ifndef HAVE_DEMANGLE
             return mn;
 #else /* !HAVE_DEMANGLE */
             int dstat;
             char *demangled = abi::__cxa_demangle(mn,0,0,&dstat);
             if(dstat)
                 return mn;
             string rv = demangled;
             free(demangled);
             return rv;
 #endif /* !HAVE_DEMANGLE */
         }
 
         string base64_signature(const assoc_t& assoc,const basic_openid_message& om) {
             const string& slist = om.get_field("signed");
             string kv;
             string::size_type p=0;
             while(true) {
                 string::size_type co = slist.find(',',p);
                 string f = (co==string::npos)
                     ?slist.substr(p):slist.substr(p,co-p);
                 kv += f;
                 kv += ':';
                 kv += om.get_field(f);
                 kv += '\n';
                 if(co==string::npos) break;
                 p = co+1;
             }
             const secret_t& secret = assoc->secret();
             const EVP_MD *evpmd;
             const string& at = assoc->assoc_type();
             if(at=="HMAC-SHA256")
                 evpmd = EVP_sha256();
             else if(at=="HMAC-SHA1")
                 evpmd = EVP_sha1();
             else
                 throw unsupported(OPKELE_CP_ "unknown association type");
             unsigned int md_len = 0;
             unsigned char md[SHA256_DIGEST_LENGTH];
             HMAC(evpmd,
                     &(secret.front()),secret.size(),
                     (const unsigned char*)kv.data(),kv.length(),
                     md,&md_len);
             return encode_base64(md,md_len);
         }
 
+        string normalize_identifier(const string& usi,bool strip_fragment) {
+            if(usi.empty())
+                return usi;
+            string rv;
+            string::size_type fsc = usi.find_first_not_of(data::_whitespace_chars);
+            if(fsc==string::npos)
+                return rv;
+            string::size_type lsc = usi.find_last_not_of(data::_whitespace_chars);
+            assert(lsc!=string::npos);
+            if(!strncasecmp(usi.c_str()+fsc,"xri://",sizeof("xri://")-1))
+                fsc += sizeof("xri://")-1;
+            if( (fsc+1) >= lsc )
+                return rv;
+            rv.assign(usi,fsc,lsc-fsc+1);
+            if(strchr(data::_iname_leaders,rv[0])) {
+                /* TODO: further normalize xri identity, fold case or
+                 * whatever... */
+            }else{
+                if(rv.find("://")==string::npos)
+                    rv.insert(0,"http://");
+                if(strip_fragment) {
+                    string::size_type fp = rv.find('#');
+                    if(fp!=string::npos) {
+                        string::size_type qp = rv.find('?');
+                        if(qp==string::npos || qp<fp)
+                            rv.erase(fp);
+                        else if(qp>fp)
+                            rv.erase(fp,qp-fp);
+                    }
+                }
+                rv = rfc_3986_normalize_uri(rv);
+            }
+            return rv;
+        }
+
     }
 
 }