Added utils functions allowing ellipsing strings when too long

The targetted use case is truncation of long log parameters.

common/utils/UtilsTest.cpp

@@ -648,4 +648,14 @@ TEST_F(cta_UtilsTest, testCopyString) {
   ASSERT_EQ(0, strcmp(dst, src));
 }
 
+TEST_F(cta_UtilsTest, ellipses) {
+  using namespace cta::utils;
+  
+  ASSERT_EQ("1234567890", postEllipsis("1234567890", 12));
+  ASSERT_EQ("1234567[...]", postEllipsis("1234567890ABCDEF", 12));
+  ASSERT_EQ("1234567890", midEllipsis("1234567890", 12));
+  ASSERT_EQ("123[...]CDEF", midEllipsis("1234567890ABCDEF", 12));
+  ASSERT_EQ("1[...]ABCDEF", midEllipsis("1234567890ABCDEF", 12, 1));
+}
+
 } // namespace unitTests

common/utils/utils.cpp

@@ -259,6 +259,32 @@ std::string trimString(const std::string &s) throw() {
   return std::string(it1, it2);
 }
 
+//------------------------------------------------------------------------------
+// postEllipsis
+//------------------------------------------------------------------------------
+std::string postEllipsis(const std::string &s, size_t maxSize) {
+  std::string ellipsis = "[...]";
+  if (maxSize < ellipsis.size())
+    throw cta::exception::Exception("In cta::utils::postEllipsis(): maxSize cannot be smaller than ellipsis size");
+  if (s.size() <= maxSize)
+    return s;
+  return s.substr(0, maxSize - ellipsis.size()) + ellipsis;
+}
+
+//------------------------------------------------------------------------------
+// midEllipsis
+//------------------------------------------------------------------------------
+std::string midEllipsis(const std::string &s, size_t maxSize, size_t beginingSize) {
+  std::string ellipsis = "[...]";
+  if (maxSize < ellipsis.size() + beginingSize)
+    throw cta::exception::Exception("In cta::utils::midEllipsis(): maxSize cannot be smaller than ellipsis size + beginingSize");
+  if (s.size() <= maxSize)
+    return s;
+  if (!beginingSize)
+    beginingSize = (maxSize - ellipsis.size()) / 2;
+  return s.substr(0, beginingSize) + ellipsis + s.substr(s.size() - maxSize + ellipsis.size() + beginingSize);
+}
+
 //------------------------------------------------------------------------------
 // singleSpaceString
 //------------------------------------------------------------------------------

common/utils/utils.hpp

@@ -109,8 +109,31 @@ namespace utils {
    * @param s The string to be trimmed.
    * @return The result of trimming the string.
    */
-  std::string trimString(const std::string &s) throw();
+  std::string trimString(const std::string &s) noexcept;
+  
+  /**
+   * Returns a string with an ellipsis in the end if necessary so that the 
+   * string plus ellipsis does not exceed the maxSize. The returned string is 
+   * identical to s if it fits the maximum size.
+   * @param s the string
+   * @param maxSize
+   * @return the ellipsed string
+   */
+  std::string postEllipsis(const std::string &s, size_t maxSize);
 
+  /**
+   * Returns a string with an ellipsis in the middle if necessary so that the 
+   * string plus ellipsis does not exceed the maxSize. The returned string is 
+   * identical to s if it fits the maximum size. The parts before and after the
+   * ellipsis are evenly distributed, unless beginingSize is set to a non zero 
+   * value. 
+   * @param s the string
+   * @param maxSize
+   * @param beginingSize
+   * @return the ellipsed string
+   */
+  
+  std::string midEllipsis(const std::string &s, size_t maxSize, size_t beginingSize = 0);
   /**
    * Returns uuid in the form of a string.
    *