aded util::url_decode()

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

1 files changed, 28 insertions, 0 deletions

diff --git a/lib/util.cc b/lib/util.cc
index a6e08e2..3e7f3aa 100644
--- a/lib/util.cc
+++ b/lib/util.cc
@@ -147,96 +147,124 @@ namespace opkele {
             tm_t.tm_year-=1900;
             time_t rv = mktime(&tm_t);
             if(rv==(time_t)-1)
                 throw failed_conversion(OPKELE_CP_ "failed to mktime()");
             return rv-timezone;
         }
 
         /*
          *
          */
 
         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++) = 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;