Add center filter (#179)

* Add center filter * Add additional test
jinja2cpp · Nov 2, 2019 · 78e0a7c · 78e0a7c
1 parent ebe0bf5
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Showing 5 changed files with 27 additions and 2 deletions.
diff --git a/README.md b/README.md
@@ -96,7 +96,7 @@ More detailed examples and features description can be found in the documentatio
 ## Current Jinja2 support
 Currently, Jinja2C++ supports the limited number of Jinja2 features. By the way, Jinja2C++ is planned to be a full [jinja2 specification](http://jinja.pocoo.org/docs/2.10/templates/)-conformant. The current support is limited to:
 -  expressions. You can use almost every expression style: simple, filtered, conditional, and so on.
--  the big number of filters (**sort, default, first, last, length, max, min, reverse, unique, sum, attr, map, reject, rejectattr, select, selectattr, pprint, dictsort, abs, float, int, list, round, random, trim, title, upper, wordcount, replace, truncate, groupby, urlencode, capitalize, escape, tojson, striptags**)
+-  the big number of filters (**sort, default, first, last, length, max, min, reverse, unique, sum, attr, map, reject, rejectattr, select, selectattr, pprint, dictsort, abs, float, int, list, round, random, trim, title, upper, wordcount, replace, truncate, groupby, urlencode, capitalize, escape, tojson, striptags, center**)
 -  the big number of testers (**eq, defined, ge, gt, iterable, le, lt, mapping, ne, number, sequence, string, undefined, in, even, odd, lower, upper**)
 -  the number of functions (**range**, **loop.cycle**)
 -  'if' statement (with 'elif' and 'else' branches)

diff --git a/src/filters.cpp b/src/filters.cpp
@@ -41,6 +41,7 @@ std::unordered_map<std::string, ExpressionFilter::FilterFactoryFn> s_filters = {
     {"batch", FilterFactory<filters::Slice>::MakeCreator(filters::Slice::BatchMode)},
     {"camelize", FilterFactory<filters::StringConverter>::MakeCreator(filters::StringConverter::CamelMode)},
     {"capitalize", FilterFactory<filters::StringConverter>::MakeCreator(filters::StringConverter::CapitalMode)},
+    {"center", FilterFactory<filters::StringConverter>::MakeCreator(filters::StringConverter::CenterMode)},
     {"default", &FilterFactory<filters::Default>::Create},
     {"d", &FilterFactory<filters::Default>::Create},
     {"dictsort", &FilterFactory<filters::DictSort>::Create},

diff --git a/src/filters.h b/src/filters.h
@@ -190,7 +190,8 @@ class StringConverter : public  FilterBase
         WordCountMode,
         WordWrapMode,
         UnderscoreMode,
-        UrlEncodeMode
+        UrlEncodeMode,
+        CenterMode
     };
 
     StringConverter(FilterParams params, Mode mode);

diff --git a/src/string_converter_filter.cpp b/src/string_converter_filter.cpp
@@ -176,6 +176,9 @@ StringConverter::StringConverter(FilterParams params, StringConverter::Mode mode
     case TruncateMode:
         ParseParams({{"length", false, static_cast<int64_t>(255)}, {"killwords", false, false}, {"end", false, std::string("...")}, {"leeway", false}}, params);
         break;
+    case CenterMode:
+        ParseParams({{"width", false, static_cast<int64_t>(80)}}, params);
+        break;
     default: break;
     }
 }
@@ -368,6 +371,19 @@ InternalValue StringConverter::Filter(const InternalValue& baseVal, RenderContex
             return str;
         });
         break;
+    case CenterMode:
+        result = ApplyStringConverter(baseVal, [this, &context](auto srcStr) -> TargetString {
+            auto width = ConvertToInt(this->GetArgumentValue("width", context));
+            auto str = sv_to_string(srcStr);
+            auto string_length = static_cast<long long int>(str.size());
+            if ( string_length >= width )
+                return str;
+            auto whitespaces = width - string_length;
+            str.insert(0, (whitespaces + 1) / 2, ' ');
+            str.append(whitespaces / 2, ' ');
+            return TargetString(std::move(str));
+        });
+        break;
     default:
         break;
     }

diff --git a/test/filters_test.cpp b/test/filters_test.cpp
@@ -564,3 +564,10 @@ INSTANTIATE_TEST_CASE_P(Striptags, FilterGenericTest, ::testing::Values(
                             InputOutputPair{"'&amp;&apos;&gt;&lt;&quot;&#39;\"&#34;' | striptags | pprint", "'&\'><\"\'\"\"'"},
                             InputOutputPair{"'&#34;&#39;' | striptags | pprint", "'\"\''"}));
 
+
+INSTANTIATE_TEST_CASE_P(Center, FilterGenericTest, ::testing::Values(
+                            InputOutputPair{" 'x' | center | pprint", "'                                        x                                       '"},
+                            InputOutputPair{" 'x' | center(width=5) | pprint", "'  x  '"},
+                            InputOutputPair{" 'x' | center(width=0) | pprint", "'x'"},
+                            InputOutputPair{" '  x' | center(width=5) | pprint", "'   x '"}
+                            ));