make stringifyHexLine() simply work on std::string stringifyhexline

Trying to construct a string using sprintf() and std::stringstream
is unnecessarily complicated for something as simple as this,
and it shows up in my profiling. This commit makes the hex values
change to uppercase because that's what hexFromByte() returns,
but I don't think it matters.

Signed-off-by: Luboš Luňák <l.lunak@collabora.com>
Change-Id: I31c7b8e7cf4c2a495eca0bf03ae4cab53b26a04b

1 files changed, 14 insertions, 11 deletions

diff --git a/common/Util.hpp b/common/Util.hpp
index 5974a8bf20..ee68e66651 100644
--- a/common/Util.hpp
+++ b/common/Util.hpp
@@ -307,31 +307,34 @@ namespace Util
     inline std::string stringifyHexLine(const T& buffer, std::size_t offset,
                                         const std::size_t width = 32)
     {
-        char scratch[64];
-        std::stringstream os;
+        std::string str;
+        str.reserve(width * 4 + width / 8 + 3 + 1);
 
         for (unsigned int i = 0; i < width; i++)
         {
             if (i && (i % 8) == 0)
-                os << ' ';
+                str.push_back(' ');
             if ((offset + i) < buffer.size())
-                sprintf (scratch, "%.2x ", (unsigned char)buffer[offset+i]);
+            {
+                const unsigned short hex = hexFromByte(buffer[offset+i]);
+                str.push_back(hex >> 8);
+                str.push_back(hex & 0xff);
+                str.push_back(' ');
+            }
             else
-                sprintf (scratch, "   ");
-            os << scratch;
+                str.append(3, ' ');
         }
-        os << " | ";
+        str.append(" | ");
 
         for (unsigned int i = 0; i < width; i++)
         {
             if ((offset + i) < buffer.size())
-                sprintf(scratch, "%c", ::isprint(buffer[offset + i]) ? buffer[offset + i] : '.');
+                str.push_back(::isprint(buffer[offset + i]) ? buffer[offset + i] : '.');
             else
-                sprintf(scratch, " "); // Leave blank if we are out of data.
-            os << scratch;
+                str.push_back(' '); // Leave blank if we are out of data.
         }
 
-        return os.str();
+        return str;
     }
 
     /// Dump data as hex and chars to stream.