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wesm pushed a commit to branch master
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The following commit(s) were added to refs/heads/master by this push:
new 08142bf ARROW-3250: [C++] Buffer implementation which owns memory
from a std::string
08142bf is described below
commit 08142bfcfbb485a1400deed093117b87afa45725
Author: Wes McKinney <[email protected]>
AuthorDate: Mon Oct 1 04:09:10 2018 -0400
ARROW-3250: [C++] Buffer implementation which owns memory from a std::string
Author: Wes McKinney <[email protected]>
Author: Atri Sharma <[email protected]>
Closes #2660 from atris/stlstring_buffer and squashes the following commits:
60a10d553 <Wes McKinney> Initiative differently to avoid SSO issues
dafb078ef <Wes McKinney> Move implementation to Buffer::FromString with
rvalue-reference
ea342b8da <Atri Sharma> ARROW-3250: Buffer implementation to own memory
from a std::string
---
cpp/src/arrow/buffer-test.cc | 15 +++++++++++++++
cpp/src/arrow/buffer.cc | 16 ++++++++++++++++
cpp/src/arrow/buffer.h | 6 ++++++
3 files changed, 37 insertions(+)
diff --git a/cpp/src/arrow/buffer-test.cc b/cpp/src/arrow/buffer-test.cc
index b664250..6ee6076 100644
--- a/cpp/src/arrow/buffer-test.cc
+++ b/cpp/src/arrow/buffer-test.cc
@@ -141,6 +141,21 @@ TEST(TestMutableBuffer, Wrap) {
ASSERT_EQ(4, values[1]);
}
+TEST(TestBuffer, FromStringRvalue) {
+ std::string expected = "input data";
+
+ std::shared_ptr<Buffer> buffer;
+ {
+ std::string data_str = "input data";
+ buffer = Buffer::FromString(std::move(data_str));
+ }
+
+ ASSERT_FALSE(buffer->is_mutable());
+
+ ASSERT_EQ(0, memcmp(buffer->data(), expected.c_str(), expected.size()));
+ ASSERT_EQ(static_cast<int64_t>(expected.size()), buffer->size());
+}
+
TEST(TestBuffer, SliceMutableBuffer) {
std::string data_str = "some data to slice";
auto data = reinterpret_cast<const uint8_t*>(data_str.c_str());
diff --git a/cpp/src/arrow/buffer.cc b/cpp/src/arrow/buffer.cc
index 006fe0f..01bb0c3 100644
--- a/cpp/src/arrow/buffer.cc
+++ b/cpp/src/arrow/buffer.cc
@@ -71,6 +71,22 @@ Status Buffer::FromString(const std::string& data,
std::shared_ptr<Buffer>* out)
return FromString(data, default_memory_pool(), out);
}
+class StlStringBuffer : public Buffer {
+ public:
+ explicit StlStringBuffer(std::string&& data) : Buffer(nullptr, 0),
input_(data) {
+ data_ = reinterpret_cast<const uint8_t*>(input_.c_str());
+ size_ = static_cast<int64_t>(input_.size());
+ capacity_ = size_;
+ }
+
+ private:
+ std::string input_;
+};
+
+std::shared_ptr<Buffer> Buffer::FromString(std::string&& data) {
+ return std::make_shared<StlStringBuffer>(std::move(data));
+}
+
std::string Buffer::ToString() const {
return std::string(reinterpret_cast<const char*>(data_),
static_cast<size_t>(size_));
}
diff --git a/cpp/src/arrow/buffer.h b/cpp/src/arrow/buffer.h
index 75d0c21..d37a336 100644
--- a/cpp/src/arrow/buffer.h
+++ b/cpp/src/arrow/buffer.h
@@ -124,6 +124,12 @@ class ARROW_EXPORT Buffer {
/// using the default memory pool
static Status FromString(const std::string& data, std::shared_ptr<Buffer>*
out);
+ /// \brief Construct an immutable buffer that takes ownership of the contents
+ /// of an std::string
+ /// \param[in] data an rvalue-reference of a string
+ /// \return a new Buffer instance
+ static std::shared_ptr<Buffer> FromString(std::string&& data);
+
/// \brief Create buffer referencing typed memory with some length without
/// copying
/// \param[in] data the typed memory as C array
