From 0b078955eeb18e8b039c51bb25850f63b947b3cd Mon Sep 17 00:00:00 2001
From: Panchen Xue <pan.panchen.xue@gmail.com>
Date: Thu, 18 Jan 2018 18:04:23 -0500
Subject: [PATCH] ARROW-1945: [C++] Add data_capacity_ to track capacity of
 value data

---
 cpp/src/arrow/builder.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/cpp/src/arrow/builder.h b/cpp/src/arrow/builder.h
index 59293bff4b8c2..a708122c2930b 100644
--- a/cpp/src/arrow/builder.h
+++ b/cpp/src/arrow/builder.h
@@ -688,7 +688,7 @@ class ARROW_EXPORT BinaryBuilder : public ArrayBuilder {
   /// \return size of values buffer so far
   int64_t value_data_length() const { return value_data_builder_.length(); }
   /// \return capacity of values buffer
-  int64_t value_data_capacity() const { return value_data_builder_.capacity(); }
+  int64_t value_data_capacity() const { return data_capacity_; }
 
   /// Temporary access to a value.
   ///
@@ -699,6 +699,7 @@ class ARROW_EXPORT BinaryBuilder : public ArrayBuilder {
   TypedBufferBuilder<int32_t> offsets_builder_;
   TypedBufferBuilder<uint8_t> value_data_builder_;
 
+  int64_t data_capacity_;
   static constexpr int64_t kMaximumCapacity = std::numeric_limits<int32_t>::max() - 1;
 
   Status AppendNextOffset();