Add Buffer::Range

src/core/Buffer.h

@@ -19,6 +19,8 @@ public:
         INVALID_CHANGE_OPERATION_INDEX = 0xFFFFFFFFu,
     };
 
+    struct Range;
+
     class Iterator
     {
     public:
@@ -98,11 +100,51 @@ public:
         size_t offset() const { return m_offset; }
 
     protected:
+        friend struct Range;
+
         const Buffer * m_buffer;
         size_t m_offset;
         size_t m_line;
     };
 
+    struct Range
+    {
+        std::shared_ptr<Iterator> start;
+        std::shared_ptr<Iterator> end;
+
+        Range(std::shared_ptr<Iterator> _start, std::shared_ptr<Iterator> _end)
+            : start(_start), end(_end)
+        {
+        }
+
+        bool valid() const
+        {
+            return start->valid() && (!end->valid() || (*start <= *end));
+        }
+
+        size_t start_offset() const
+        {
+            return start->offset();
+        }
+
+        size_t end_offset() const
+        {
+            if (end->valid())
+            {
+                return end->offset();
+            }
+            else
+            {
+                return start->m_buffer->size();
+            }
+        }
+
+        size_t size() const
+        {
+            return end_offset() - start_offset();
+        }
+    };
+
     Buffer();
     Buffer(const char * filename);
     Buffer(const uint8_t * data, size_t data_length);