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Jakob Widauer
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feat: adds front and back methods to Value type (open-source-parsers#1458)
Value::front and Value::back
1 parent 8190e06 commit 3d9bf8e

2 files changed

Lines changed: 38 additions & 0 deletions

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‎include/json/value.h‎

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@@ -585,6 +585,22 @@ class JSON_API Value {
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iterator begin();
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iterator end();
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/// \brief Returns a reference to the first element in the `Value`.
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/// Requires that this value holds an array or json object, with at least one element.
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const Value& front() const;
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/// \brief Returns a reference to the first element in the `Value`.
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/// Requires that this value holds an array or json object, with at least one element.
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Value& front();
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/// \brief Returns a reference to the last element in the `Value`.
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/// Requires that value holds an array or json object, with at least one element.
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const Value& back() const;
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/// \brief Returns a reference to the last element in the `Value`.
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/// Requires that this value holds an array or json object, with at least one element.
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Value& back();
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// Accessors for the [start, limit) range of bytes within the JSON text from
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// which this value was parsed, if any.
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void setOffsetStart(ptrdiff_t start);
@@ -925,6 +941,14 @@ class JSON_API ValueIterator : public ValueIteratorBase {
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inline void swap(Value& a, Value& b) { a.swap(b); }
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inline const Value& Value::front() const { return *begin(); }
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inline Value& Value::front() { return *begin(); }
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inline const Value& Value::back() const { return *(--end()); }
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inline Value& Value::back() { return *(--end()); }
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} // namespace Json
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#pragma pack(pop)

‎src/test_lib_json/main.cpp‎

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@@ -310,10 +310,14 @@ JSONTEST_FIXTURE_LOCAL(ValueTest, arrays) {
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const Json::Value& constArray = array1_;
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JSONTEST_ASSERT_EQUAL(Json::Value(1234), constArray[index0]);
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JSONTEST_ASSERT_EQUAL(Json::Value(1234), constArray[0]);
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JSONTEST_ASSERT_EQUAL(Json::Value(1234), constArray.front());
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JSONTEST_ASSERT_EQUAL(Json::Value(1234), constArray.back());
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// Access through non-const reference
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JSONTEST_ASSERT_EQUAL(Json::Value(1234), array1_[index0]);
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JSONTEST_ASSERT_EQUAL(Json::Value(1234), array1_[0]);
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JSONTEST_ASSERT_EQUAL(Json::Value(1234), array1_.front());
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JSONTEST_ASSERT_EQUAL(Json::Value(1234), array1_.back());
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array1_[2] = Json::Value(17);
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JSONTEST_ASSERT_EQUAL(Json::Value(), array1_[1]);
@@ -356,6 +360,8 @@ JSONTEST_FIXTURE_LOCAL(ValueTest, resizePopulatesAllMissingElements) {
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v.resize(n);
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JSONTEST_ASSERT_EQUAL(n, v.size());
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JSONTEST_ASSERT_EQUAL(n, std::distance(v.begin(), v.end()));
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JSONTEST_ASSERT_EQUAL(v.front(), Json::Value{});
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JSONTEST_ASSERT_EQUAL(v.back(), Json::Value{});
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for (const Json::Value& e : v)
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JSONTEST_ASSERT_EQUAL(e, Json::Value{});
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}
@@ -406,13 +412,17 @@ JSONTEST_FIXTURE_LOCAL(ValueTest, arrayInsertAtRandomIndex) {
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JSONTEST_ASSERT_EQUAL(Json::Value("index0"), array[0]); // check append
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JSONTEST_ASSERT_EQUAL(Json::Value("index1"), array[1]);
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JSONTEST_ASSERT_EQUAL(Json::Value("index2"), array[2]);
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JSONTEST_ASSERT_EQUAL(Json::Value("index0"), array.front());
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JSONTEST_ASSERT_EQUAL(Json::Value("index2"), array.back());
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// insert lvalue at the head
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JSONTEST_ASSERT(array.insert(0, str1));
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JSONTEST_ASSERT_EQUAL(Json::Value("index3"), array[0]);
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JSONTEST_ASSERT_EQUAL(Json::Value("index0"), array[1]);
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JSONTEST_ASSERT_EQUAL(Json::Value("index1"), array[2]);
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JSONTEST_ASSERT_EQUAL(Json::Value("index2"), array[3]);
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JSONTEST_ASSERT_EQUAL(Json::Value("index3"), array.front());
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JSONTEST_ASSERT_EQUAL(Json::Value("index2"), array.back());
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// checking address
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for (Json::ArrayIndex i = 0; i < 3; i++) {
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JSONTEST_ASSERT_EQUAL(vec[i], &array[i]);
@@ -425,6 +435,8 @@ JSONTEST_FIXTURE_LOCAL(ValueTest, arrayInsertAtRandomIndex) {
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JSONTEST_ASSERT_EQUAL(Json::Value("index4"), array[2]);
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JSONTEST_ASSERT_EQUAL(Json::Value("index1"), array[3]);
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JSONTEST_ASSERT_EQUAL(Json::Value("index2"), array[4]);
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JSONTEST_ASSERT_EQUAL(Json::Value("index3"), array.front());
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JSONTEST_ASSERT_EQUAL(Json::Value("index2"), array.back());
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// checking address
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for (Json::ArrayIndex i = 0; i < 4; i++) {
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JSONTEST_ASSERT_EQUAL(vec[i], &array[i]);
@@ -438,6 +450,8 @@ JSONTEST_FIXTURE_LOCAL(ValueTest, arrayInsertAtRandomIndex) {
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JSONTEST_ASSERT_EQUAL(Json::Value("index1"), array[3]);
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JSONTEST_ASSERT_EQUAL(Json::Value("index2"), array[4]);
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JSONTEST_ASSERT_EQUAL(Json::Value("index5"), array[5]);
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JSONTEST_ASSERT_EQUAL(Json::Value("index3"), array.front());
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JSONTEST_ASSERT_EQUAL(Json::Value("index5"), array.back());
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// checking address
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for (Json::ArrayIndex i = 0; i < 5; i++) {
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JSONTEST_ASSERT_EQUAL(vec[i], &array[i]);

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