Move "to_hex()" function from mkvinfo.cpp to the string formatting library

src/common/strings/formatting.cpp

@@ -240,3 +240,15 @@ format_paragraph(const std::string &text_to_wrap,
                  const char *break_chars) {
   return to_utf8(format_paragraph(to_wide(text_to_wrap), indent_column, to_wide(indent_first_line), to_wide(indent_following_lines), wrap_column, to_wide(break_chars)));
 }
+
+std::string
+to_hex(const unsigned char *buf,
+       size_t size) {
+  static boost::format s_bf_to_hex("%|1$02x| ");
+
+  std::string hex("0x");
+  for (size_t idx = 0; idx < size; ++idx)
+    hex += (s_bf_to_hex % static_cast<unsigned int>(buf[idx])).str();
+
+  return hex;
+}

src/common/strings/formatting.h

@@ -60,4 +60,10 @@ std::string to_string(uint64_t value);
 std::string to_string(double value, unsigned int precision);
 std::string to_string(int64_t numerator, int64_t denominator, unsigned int precision);
 
+std::string to_hex(const unsigned char *buf, size_t size);
+inline std::string
+to_hex(const std::string &buf) {
+  return to_hex(reinterpret_cast<const unsigned char *>(buf.c_str()), buf.length());
+}
+
 #endif  // __MTX_COMMON_STRING_FORMATTING_H

src/info/mkvinfo.cpp

@@ -321,19 +321,6 @@ create_hexdump(const unsigned char *buf,
   return hex;
 }
 
-static std::string
-to_hex(const unsigned char *buf,
-       int size) {
-  static boost::format s_bf_to_hex(" 0x%|1$02x|");
-
-  std::string hex;
-  int b;
-  for (b = 0; b < size; ++b)
-    hex += (s_bf_to_hex % (int)buf[b]).str();
-
-  return hex;
-}
-
 std::string
 create_codec_dependent_private_info(KaxCodecPrivate &c_priv,
                                     char track_type,