Add new function QUtil::hex_encode_char

m-holger · Jay Berkenbilt
1 parent 1326ff7f
Showing 2 changed files with 14 additions and 1 deletions
include/qpdf/QUtil.hh
libqpdf/QPDF_Name.cc
@@ -210,6 +210,11 @@ namespace QUtil
     QPDF_DLL
     std::string hex_encode(std::string const&);
  
+    // Returns lower-case hex-encoded version of the char including a leading
+    // "#".
+    QPDF_DLL
+    inline std::string hex_encode_char(char);
+
     // Returns a string that is the result of decoding the input
     // string. The input string may consist of mixed case hexadecimal
     // digits. Any characters that are not hexadecimal digits will be
@@ -583,4 +588,12 @@ QUtil::is_number(char const* p)
     return found_digit;
 }
  
+inline std::string
+QUtil::hex_encode_char(char c)
+{
+    static auto constexpr hexchars = "0123456789abcdef";
+    return {
+        '#', hexchars[static_cast<unsigned char>(c) >> 4], hexchars[c & 0x0f]};
+}
+
 #endif // QUTIL_HH
@@ -38,7 +38,7 @@ QPDF_Name::normalizeName(std::string const&amp; name)
             // invalid #.
             result += "#";
         } else if (strchr("#()<>[]{}/%", ch) || (ch < 33) || (ch > 126)) {
-            result += "#" + QUtil::hex_encode(std::string(&ch, 1));
+            result += QUtil::hex_encode_char(ch);
         } else {
             result += ch;
         }