Query_ID

clickhouse/block.cpp

@@ -10,6 +10,11 @@ Block::Iterator::Iterator(const Block& block)
 {
 }
 
+Block::Iterator::Iterator(const Block& block, Block::Iterator::ConstructAtEndTag /*at_end*/)
+    : block_(block)
+    , idx_(block.GetColumnCount())
+{}
+
 const std::string& Block::Iterator::Name() const {
     return block_.columns_[idx_].name;
 }
@@ -22,8 +27,9 @@ ColumnRef Block::Iterator::Column() const {
     return block_.columns_[idx_].column;
 }
 
-void Block::Iterator::Next() {
+bool Block::Iterator::Next() {
     ++idx_;
+    return IsValid();
 }
 
 bool Block::Iterator::IsValid() const {
@@ -95,4 +101,12 @@ ColumnRef Block::operator [] (size_t idx) const {
     throw std::out_of_range("column index is out of range. Index: ["+std::to_string(idx)+"], columns: [" + std::to_string(columns_.size())+"]");
 }
 
+Block::Iterator Block::begin() const {
+    return Iterator(*this);
+}
+
+Block::Iterator Block::end() const {
+    return Iterator(*this, Iterator::ConstructAtEndTag{});
+}
+
 }

clickhouse/block.h

@@ -25,13 +25,35 @@ class Block {
         /// Reference to column object.
         ColumnRef Column() const;
 
-        /// Move to next column.
-        void Next();
+        /// Move to next column, returns false if next call to IsValid() would return false;
+        bool Next();
 
         /// Is the iterator still valid.
         bool IsValid() const;
 
+        size_t ColumnIndex() const {
+            return idx_;
+        }
+
+        Iterator& operator*() { return *this; }
+        const Iterator& operator*() const { return *this; }
+
+        bool operator==(const Iterator & other) const {
+            return &block_ == &other.block_ && idx_ == other.idx_;
+        }
+        bool operator!=(const Iterator & other) const {
+            return !(*this == other);
+        }
+
+        Iterator& operator++() {
+            this->Next();
+            return *this;
+        }
+
     private:
+        friend class Block;
+        struct ConstructAtEndTag {};
+        Iterator(const Block& block, ConstructAtEndTag at_end);
         Iterator() = delete;
 
         const Block& block_;
@@ -63,6 +85,11 @@ class Block {
     /// Reference to column by index in the block.
     ColumnRef operator [] (size_t idx) const;
 
+    Iterator begin() const;
+    Iterator end() const;
+    Iterator cbegin() const { return begin(); }
+    Iterator cend() const { return end(); }
+
 private:
     struct ColumnItem {
         std::string name;