Fixed w3c to unix timestamp conversion for FreeBSD

Thanks to Göran Löwkrantz for pointing both to the problem and possible
solution.

Signed-off-by: Michael Krelin <hacker@klever.net>

2 files changed, 19 insertions, 3 deletions

diff --git a/configure.ac b/configure.ac
index 3194718..3484146 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,258 +1,259 @@
 AC_INIT([libopkele], [2.0], [libopkele-bugs@klever.net])
 AC_CONFIG_SRCDIR([include/opkele/opkele-config.h])
 AC_CONFIG_HEADERS([config.h include/opkele/acconfig.h])
 AM_INIT_AUTOMAKE([dist-bzip2])
 
 AC_PROG_INSTALL
 AC_PROG_CXX
 AC_PROG_CC
 AC_PROG_LIBTOOL
 PKG_PROG_PKG_CONFIG
 
 AC_HEADER_STDC
+AC_CHECK_FUNCS([timegm])
 
 AC_PATH_PROG([XSLTPROC],[xsltproc],[true])
 
 AC_MSG_CHECKING([for source tree version])
 if headrev=$(cd $srcdir && git rev-parse --verify HEAD 2>/dev/null) ; then
  PACKAGE_SRC_VERSION="$(cd $srcdir && git describe --tags $headrev)"
  test "$PACKAGE_SRC_VERSION" = "$PACKAGE_VERSION" \
   -o "${PACKAGE_SRC_VERSION#${PACKAGE_VERSION}-}" != "$PACKAGE_SRC_VERSION" || PACKAGE_SRC_VERSION="${PACKAGE_VERSION}:${PACKAGE_SRC_VERSION}"
  ( cd $srcdir && git diff-index $headrev | read dirt ) && PACKAGE_SRC_VERSION="${PACKAGE_SRC_VERSION}-dirty"
 else
  PACKAGE_SRC_VERSION="$PACKAGE_VERSION"
 fi
 AC_MSG_RESULT([$PACKAGE_SRC_VERSION])
 AC_SUBST([PACKAGE_SRC_VERSION])
 AC_DEFINE_UNQUOTED([PACKAGE_SRC_VERSION],["$PACKAGE_SRC_VERSION"],[more or less precise source tree version])
 
 tr1_mem_std="false"
 tr1_mem_boost="false"
 AC_CHECK_SHAREDPTR(std::tr1,tr1/memory,[ tr1_mem_std=true ])
 AC_CHECK_SHAREDPTR(boost,boost/shared_ptr.hpp,[ tr1_mem_boost=true ])
 tr1_mem=""
 AC_ARG_WITH([tr1-memory],
  AC_HELP_STRING([--with-tr1-memory=<boost|std>],[select tr1/memory (shared_ptr<>) implementation to use]),
  [ tr1_mem="$withval" ]
 )
 AC_MSG_CHECKING([for tr1/memory implementation to use])
 test -z "$tr1_mem" && $tr1_mem_std && tr1_mem=std
 test -z "$tr1_mem" && $tr1_mem_boost && tr1_mem=boost
 if test -z "$tr1_mem" ; then
  AC_MSG_RESULT([none found])
 else
  AC_MSG_RESULT([$tr1_mem])
 fi
 case "$tr1_mem" in
  std)
   $tr1_mem_std || AC_MSG_ERROR([std implementation requested, but not found])
   OPKELE_TR1_MEM_NS=std::tr1
   OPKELE_TR1_MEM_HEADER=tr1/memory
   ;;
  boost)
   $tr1_mem_boost || AC_MSG_ERROR([boost implementation requested, but not found])
   OPKELE_TR1_MEM_NS=boost
   OPKELE_TR1_MEM_HEADER=boost/shared_ptr.hpp
   ;;
  *)
   AC_MSG_ERROR([no shared_ptr<> implementation found])
   ;;
 esac
 AC_SUBST([OPKELE_TR1_MEM_NS])
 AC_SUBST([OPKELE_TR1_MEM_HEADER])
 
 AC_MSG_CHECKING([for deprecated attribute support])
 AC_COMPILE_IFELSE([
   int __attribute__((deprecated)) deprecated_function();
  ],[
   AC_MSG_RESULT([yes])
   AC_DEFINE([OPKELE_DEPRECATE],[__attribute__((deprecated))],[deprecated function attribute])
  ],[
   AC_MSG_RESULT([no])
   AC_DEFINE([OPKELE_DEPRECATE],,[deprecated function attribute])
  ]
 )
 
 AC_LANG_PUSH([C++])
 AC_MSG_CHECKING([for abi::__cxa_demangle])
 AC_COMPILE_IFELSE([
   #include <typeinfo>
   using namespace std;
   #include <cxxabi.h>
   int main(int c,char **v) {
    int dstat;
    char *demangled = abi::__cxa_demangle(typeid(dstat).name(),0,0,&dstat);
    return 0;
   }
  ],[
   AC_MSG_RESULT([yes])
   AC_DEFINE([HAVE_DEMANGLE],,[defined if abi::__cxa_demangle is available])
  ],[
   AC_MSG_RESULT([no])
  ]
 )
 AC_LANG_POP([C++])
 
 
 
 
 PKG_CHECK_MODULES([OPENSSL],[openssl],,[
  AC_MSG_ERROR([no openssl library found. get one from http://www.openssl.org/])
 ])
 
 WANT_KONFORKA="yes"
 AC_ARG_ENABLE([konforka],
  AC_HELP_STRING([--disable-konforka],[do not use konforka library (default: use if found)]),
  [
   test "${enableval}" = "no" && WANT_KONFORKA="no"
  ]
 )
 if test "${WANT_KONFORKA}" = "yes" ; then
  PKG_CHECK_MODULES([KONFORKA],[konforka],[
   AC_SUBST([KONFORKA_CFLAGS])
   AC_SUBST([KONFORKA_LIBS])
   AC_DEFINE([HAVE_KONFORKA],,[defined in presence of konforka library])
   AC_DEFINE([OPKELE_HAVE_KONFORKA],,[defined in presence of konforka library])
   AC_SUBST([KONFORKA_KONFORKA],[konforka])
  ],[true])
 fi
 
 WANT_DOXYGEN="yes"
 AC_ARG_ENABLE([doxygen],
  AC_HELP_STRING([--disable-doxygen],[do not generate documentation]),
  [
   test "${enableval}" = "no" && WANT_DOXYGEN="no"
  ]
 )
 if test "${WANT_DOXYGEN}" = "yes" ; then
  AC_WITH_DOXYGEN
  AC_WITH_DOT
 else
  AM_CONDITIONAL([HAVE_DOXYGEN],[false])
  AM_CONDITIONAL([HAVE_DOT],[false])
 fi
 
 LIBCURL_CHECK_CONFIG(,,,[
  AC_MSG_ERROR([no required libcurl library. get one from http://curl.haxx.se/])
 ])
 
 AC_CHECK_HEADER([expat.h],[
  AC_CHECK_LIB([expat],[XML_ParserCreate],[
   EXPAT_LIBS=-lexpat
   EXPAT_CFLAGS=
   AC_SUBST([EXPAT_LIBS])
   AC_SUBST([EXPAT_CFLAGS])
  ],[
   AC_MSG_ERROR([no required expat library. get one from http://expat.sourceforge.net/])
  ])
 ],[
  AC_MSG_ERROR([no required expat library. get one from http://expat.sourceforge.net/])
 ])
 
 AC_CHECK_HEADERS([tidy.h tidy/tidy.h],[
  AC_CHECK_LIB([tidy],[tidyParseBuffer],[
   TIDY_LIBS=-ltidy
   TIDY_CFLAGS=
   AC_SUBST([TIDY_LIBS])
   AC_SUBST([TIDY_CFLAGS])
  ],[
   AC_MSG_ERROR([no required htmltidy library found. get one from http://tidy.sourceforge.net/])
  ])
 ],[
  test "$ac_header" = "tidy/tidy.h" \
  && AC_MSG_ERROR([no required htmltidy library found. get one from http://tidy.sourceforge.net/])
 ])
 
 if test -n "$PCRE_LIBS" -a -n "$PCRE_CFLAGS" ; then
  AC_SUBST([PCRE_CFLAGS])
  AC_SUBST([PCRE_LIBS])
  :
 else
  PKG_CHECK_MODULES([PCRE],[libpcre],,[
   AC_MSG_ERROR([no libpcre found, go get it at http://www.pcre.org/])
  ])
 fi
 
 PKG_CHECK_MODULES([SQLITE3],[sqlite3],[have_sqlite3=true],[have_sqlite3=false])
 AM_CONDITIONAL([HAVE_SQLITE3],[$have_sqlite3])
 PKG_CHECK_MODULES([KINGATE],[kingate-plaincgi],[have_kingate=true],[have_kingate=false])
 AM_CONDITIONAL([HAVE_KINGATE],[$have_kingate])
 PKG_CHECK_MODULES([UUID],[uuid],[have_uuid=true],[have_uuid=false])
 AM_CONDITIONAL([HAVE_UUID],[$have_uuid])
 if $have_uuid ; then
  AC_DEFINE([HAVE_LIBUUID],,[defined in presence of libuuid])
  AC_SUBST([UUID_UUID],[uuid])
 fi
 
 curl_ssl_verify_host="true"
 AC_ARG_ENABLE([ssl-verify-host],
  AC_HELP_STRING([--disable-ssl-verify-host],[disable cURL cert/host relationships verification]),
  [ test "${enableval}" = "no" && curl_ssl_verify_host="false" ]
 )
 ${curl_ssl_verify_host} || AC_DEFINE([DISABLE_CURL_SSL_VERIFYHOST],,[defined if cURL is not to verify cert/host])
 
 curl_ssl_verify_peer="true"
 AC_ARG_ENABLE([ssl-verify-peer],
  AC_HELP_STRING([--disable-ssl-verify-peer],[disable cURL cert validity verification]),
  [ test "${enableval}" = "no" && curl_ssl_verify_peer="false" ]
 )
 ${curl_ssl_verify_peer} || AC_DEFINE([DISABLE_CURL_SSL_VERIFYPEER],,[defined if cURL is not to verify cert validity])
 
 postels_law=true
 AC_ARG_ENABLE([postels-law],
  AC_HELP_STRING([--disable-postels-law],[Be strict, do not adhere to Postel's Law ("be conservative in what you do, be liberal in what you accept from others", RFC 793)]),
  [ test "${enableval}" = "no" && postels_law=false ]
 )
 $postels_law && AC_DEFINE([POSTELS_LAW],,[defined if we want to adhere to Postel's Law])
 
 AC_DEFINE_UNQUOTED([OPKELE_SRC_DIR],["$PWD"],[source directory])
 
 nitpick=false
 AC_ARG_ENABLE([nitpicking],
  AC_HELP_STRING([--enable-nitpicking],[make compiler somewhat overly fastidious about the code it deals with]),
  [ test "$enableval" = "no" || nitpick=true ]
 )
 if $nitpick ; then
  CPP_NITPICK="-pedantic -Wall -Wextra -Wundef -Wshadow \
   -Wunsafe-loop-optimizations -Wconversion -Wmissing-format-attribute \
   -Wredundant-decls -ansi"
  # -Wlogical-op -Wmissing-noreturn 
  C_NITPICK="$CPP_NITPICK"
  CXX_NITPICK="$C_NITPICK"
 
  CPPFLAGS="$CPPFLAGS $CPP_NITPICK"
  CFLAGS="$CFLAGS $C_NITPICK"
  CXXFLAGS="$CXXFLAGS $CXX_NITPICK"
 fi
 
 ndebug=true
 AC_ARG_ENABLE([debug],
  AC_HELP_STRING([--enable-debug],[enable debugging code]),
  [ test "$enableval" = "no" || ndebug=false ]
 )
 if $ndebug ; then
  CPPFLAGS_DEBUG="-DNDEBUG"
 else
  CPPFLAGS_DEBUG=""
 fi
 AC_SUBST([CPPFLAGS_DEBUG])
 
 xri_proxy_url="https://xri.net/"
 AC_MSG_CHECKING([for XRI resolver proxy])
 AC_ARG_ENABLE([xri-proxy],
  AC_HELP_STRING([--with-xri-proxy=url],[set xri proxy for use when resolving xri identities, default is https://xri.net/]),
  [ xri_proxy_url="$withval" ]
 )
 AC_MSG_RESULT([$xri_proxy_url])
 AC_DEFINE_UNQUOTED([XRI_PROXY_URL],["$xri_proxy_url"],[XRI proxy resolver URL])
 
 AC_CONFIG_FILES([
  Makefile
   libopkele.pc
   Doxyfile
  include/Makefile
   include/opkele/tr1-mem.h
  lib/Makefile
  test/Makefile
 ])
 AC_OUTPUT
diff --git a/lib/util.cc b/lib/util.cc
index d979502..a46ba2a 100644
--- a/lib/util.cc
+++ b/lib/util.cc
@@ -1,525 +1,540 @@
 #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 <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;
             }
         }
 
         /*
          * big numerics
          */
 
         BIGNUM *base64_to_bignum(const string& b64) {
             vector<unsigned char> bin;
             decode_base64(b64,bin);
             BIGNUM *rv = BN_bin2bn(&(bin.front()),bin.size(),0);
             if(!rv)
                 throw failed_conversion(OPKELE_CP_ "failed to BN_bin2bn()");
             return rv;
         }
 
         BIGNUM *dec_to_bignum(const string& dec) {
             BIGNUM *rv = 0;
             if(!BN_dec2bn(&rv,dec.c_str()))
                 throw failed_conversion(OPKELE_CP_ "failed to BN_dec2bn()");
             return rv;
         }
 
         string bignum_to_base64(const BIGNUM *bn) {
             vector<unsigned char> bin(BN_num_bytes(bn)+1);
             unsigned char *binptr = &(bin.front())+1;
             int l = BN_bn2bin(bn,binptr);
             if(l && (*binptr)&0x80){
                 (*(--binptr)) = 0; ++l;
             }
             return encode_base64(binptr,l);
         }
 
         /*
          * w3c times
          */
 
         string time_to_w3c(time_t t) {
             struct tm tm_t;
             if(!gmtime_r(&t,&tm_t))
                 throw failed_conversion(OPKELE_CP_ "failed to BN_dec2bn()");
             char rv[25];
             if(!strftime(rv,sizeof(rv)-1,"%Y-%m-%dT%H:%M:%SZ",&tm_t))
                 throw failed_conversion(OPKELE_CP_ "failed to strftime()");
             return rv;
         }
 
+#ifndef HAVE_TIMEGM
+        static time_t timegm(struct tm *t) {
+            char *tz = getenv("TZ");
+            setenv("TZ","",1); tzset();
+            time_t rv = mktime(t);
+            if(tz)
+                setenv("TZ",tz,1);
+            else
+                unsetenv("TZ");
+            tzset();
+            return rv;
+        }
+        #define timegm opkele::util::timegm
+#endif /* HAVE_TIMEGM */
+
         time_t w3c_to_time(const string& w) {
             int fraction;
             struct tm tm_t;
             memset(&tm_t,0,sizeof(tm_t));
             if( (
                         sscanf(
                             w.c_str(),
                             "%04d-%02d-%02dT%02d:%02d:%02dZ",
                             &tm_t.tm_year,&tm_t.tm_mon,&tm_t.tm_mday,
                             &tm_t.tm_hour,&tm_t.tm_min,&tm_t.tm_sec
                             ) != 6
                 ) && (
                     sscanf(
                         w.c_str(),
                         "%04d-%02d-%02dT%02d:%02d:%02d.%03dZ",
                         &tm_t.tm_year,&tm_t.tm_mon,&tm_t.tm_mday,
                         &tm_t.tm_hour,&tm_t.tm_min,&tm_t.tm_sec,
                         &fraction
                         ) != 7
                     ) )
                 throw failed_conversion(OPKELE_CP_ "failed to sscanf()");
             tm_t.tm_mon--;
             tm_t.tm_year-=1900;
-            time_t rv = mktime(&tm_t);
+            time_t rv = timegm(&tm_t);
             if(rv==(time_t)-1)
-                throw failed_conversion(OPKELE_CP_ "failed to mktime()");
-            return rv-timezone;
+                throw failed_conversion(OPKELE_CP_ "failed to gmtime()");
+            return rv;
         }
 
         /*
          *
          */
 
         static inline bool isrfc3986unreserved(int c) {
             if(c<'-') return false;
             if(c<='.') return true;
             if(c<'0') return false; if(c<='9') return true;
             if(c<'A') return false; if(c<='Z') return true;
             if(c<'_') return false;
             if(c=='_') return true;
             if(c<'a') return false; if(c<='z') return true;
             if(c=='~') return true;
             return false;
         }
 
         struct __url_encoder : public unary_function<char,void> {
             public:
                 string& rv;
 
                 __url_encoder(string& r) : rv(r) { }
 
                 result_type operator()(argument_type c) {
                     if(isrfc3986unreserved(c))
                         rv += c;
                     else{
                         char tmp[4];
                         snprintf(tmp,sizeof(tmp),"%%%02X",
                                 (c&0xff));
                         rv += tmp;
                     }
                 }
         };
 
         string url_encode(const string& str) {
             string rv;
             for_each(str.begin(),str.end(),
                     __url_encoder(rv));
             return rv;
         }
 
         string url_decode(const string& str) {
             string rv;
             back_insert_iterator<string> ii(rv);
             for(string::const_iterator i=str.begin(),ie=str.end();
                     i!=ie;++i) {
                 switch(*i) {
                     case '+':
                         *(ii++) = ' '; break;
                     case '%':
                         ++i;
                         static char tmp[3] = {0,0,0};
                         if(i==ie)
                             throw failed_conversion(OPKELE_CP_ "trailing percent in the url-encoded string");
                         tmp[0] = *(i++);
                         if(i==ie)
                             throw failed_conversion(OPKELE_CP_ "not enough hexadecimals after the percent sign in url-encoded string");
                         tmp[1] = *i;
                         if(!(isxdigit(tmp[0]) && isxdigit(tmp[1])))
                             throw failed_conversion(OPKELE_CP_ "non-hex follows percent in url-encoded string");
                         *(ii++) = (char)strtol(tmp,0,16);
                         break;
                     default:
                         *(ii++) = *i; break;
                 }
             }
             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) {
              string rv;
              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(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++];
                      tmp[1] = uri[n++];
                      if(!( isxdigit(tmp[0]) && isxdigit(tmp[1]) ))
                          throw bad_input(OPKELE_CP_ "Invalid percent-encoded character in URI being normalized");
                      int cc = strtol(tmp,0,16);
                      if( isalpha(cc) || isdigit(cc) || strchr("._~-",cc) )
                          pseg += (char)cc;
                      else{
                          pseg += '%';
                          pseg += (char)toupper(tmp[0]); pseg += (char)toupper(tmp[1]);
                      }
                  }else if(qf) {
                      rv += pseg; rv += c;
                      pseg.clear();
                  }else if(n>=ul || strchr("?/#",c)) {
                      if(pseg.empty() || pseg==".") {
                      }else if(pseg=="..") {
                          if(psegs.size()>1) {
                              rv.resize(psegs.top()); psegs.pop();
                          }
                      }else{
                          psegs.push(rv.length());
                          if(c!='/') {
                              pseg += c;
                              qf = true;
                          }
                          rv += '/'; rv += pseg;
                      }
                      if(c=='/' && (n>=ul || strchr("?#",uri[n])) ) {
                          rv += '/';
                          if(n<ul)
                              qf = true;
                      }else if(strchr("?#",c)) {
                          if(psegs.size()==1 && psegs.top()==rv.length())
                              rv += '/';
                          if(pseg.empty())
                              rv += c;
                          qf = true;
                      }
                      pseg.clear();
                  }else{
                      pseg += c;
                  }
              }
              if(!pseg.empty()) {
                  if(!qf) rv += '/';
                  rv += pseg;
              }
              return rv;
          }
 
         string& strip_uri_fragment_part(string& u) {
             string::size_type q = u.find('?'), f = u.find('#');
             if(q==string::npos) {
                 if(f!=string::npos)
                     u.erase(f);
             }else{
                 if(f!=string::npos) {
                     if(f<q)
                         u.erase(f,q-f);
                     else
                         u.erase(f);
                 }
             }
             return u;
         }
 
         bool uri_matches_realm(const string& uri,const string& realm) {
             string nrealm = opkele::util::rfc_3986_normalize_uri(realm);
             string nu = opkele::util::rfc_3986_normalize_uri(uri);
             string::size_type pr = nrealm.find("://");
             string::size_type pu = nu.find("://");
             assert(!(pr==string::npos || pu==string::npos));
             pr += sizeof("://")-1;
             pu += sizeof("://")-1;
             if(!strncmp(nrealm.c_str()+pr,"*.",2)) {
                 pr = nrealm.find('.',pr);
                 pu = nu.find('.',pu);
                 assert(pr!=string::npos);
                 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;
         }
 
     }
 
 }