added util::attr_escape

escaping string for inclusion into x(ht)ml attributes

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

2 files changed, 26 insertions, 0 deletions

diff --git a/include/opkele/util.h b/include/opkele/util.h
index 6f3ddf6..719f951 100644
--- a/include/opkele/util.h
+++ b/include/opkele/util.h
@@ -97,12 +97,19 @@ namespace opkele {
 	 * @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);
diff --git a/lib/util.cc b/lib/util.cc
index 54d6535..b7bc437 100644
--- a/lib/util.cc
+++ b/lib/util.cc
@@ -158,12 +158,31 @@ namespace opkele {
 		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;