added trim operand function.

ZString.cpp

@@ -362,6 +362,12 @@ namespace coreutils {
       return cursor >= data + length;
    }
 
+   int ZString::goeod() {
+      char *temp = cursor;
+      cursor = data + length;
+      return cursor - temp;
+   }
+   
    bool ZString::startsWith(const char *value) {
       return strncmp(cursor, value, strlen(value)) == 0;
    }
@@ -455,6 +461,19 @@ namespace coreutils {
       return len;
    }
 
+   int ZString::trimTrailingWhitespace() {
+      goeod();
+      int len = 0;
+      --cursor;
+      while((cursor > data) && ((*cursor == ' ') || (*cursor == '\n') || (*cursor == '\t'))) {
+	 --cursor;
+	 --length;
+	 ++len;
+      }      
+      ++cursor;
+      return len;
+   }
+   
    bool ZString::lineIsWhitespace() {
       char *end = data + length;
       char *temp = cursor;
@@ -496,6 +515,8 @@ namespace coreutils {
    }
 
    ZString ZString::trim() {
+      trimTrailingWhitespace();
+      reset();
       skipWhitespace();
       return unparsed();
    }