Replace many calls to sprintf with QUtil::hex_encode

Add QUtil::hex_encode to encode binary data has a hexadecimal string,
and use it in place of sprintf where possible.

1 files changed, 16 insertions, 0 deletions

diff --git a/libqpdf/QUtil.cc b/libqpdf/QUtil.cc
index 3cdfdc49..faccaee7 100644
--- a/libqpdf/QUtil.cc
+++ b/libqpdf/QUtil.cc
@@ -2,6 +2,7 @@
 #include <qpdf/qpdf-config.h>
 
 #include <qpdf/QUtil.hh>
+#include <qpdf/PointerHolder.hh>
 
 #include <stdio.h>
 #include <errno.h>
@@ -163,6 +164,21 @@ QUtil::copy_string(std::string const& str)
     return result;
 }
 
+std::string
+QUtil::hex_encode(std::string const& input)
+{
+    size_t input_size = input.length();
+    size_t hex_size = 1 + (2 * input_size);
+    PointerHolder<char> bufp(true, new char[hex_size]);
+    char* buf = bufp.getPointer();
+    buf[hex_size - 1] = '\0';
+    for (unsigned int i = 0; i < input_size; ++i)
+    {
+        sprintf(buf + i * 2, "%02x", (unsigned char)input[i]);
+    }
+    return buf;
+}
+
 void
 QUtil::binary_stdout()
 {