Merge numbuf.

numbuf/python/src/pynumbuf/memory.h

@@ -0,0 +1,68 @@
+#ifndef PYNUMBUF_MEMORY_H
+#define PYNUMBUF_MEMORY_H
+
+#include <arrow/io/interfaces.h>
+
+namespace numbuf {
+
+class FixedBufferStream : public arrow::io::OutputStream, public arrow::io::ReadableFileInterface {
+ public:
+  virtual ~FixedBufferStream() {}
+
+  explicit FixedBufferStream(uint8_t* data, int64_t nbytes)
+    : data_(data), position_(0), size_(nbytes) {}
+
+  arrow::Status Read(int64_t nbytes, std::shared_ptr<arrow::Buffer>* out) override {
+    DCHECK(out);
+    DCHECK(position_ + nbytes <= size_) << "position: " << position_ << " nbytes: " << nbytes << "size: " << size_;
+    *out = std::make_shared<arrow::Buffer>(data_ + position_, nbytes);
+    position_ += nbytes;
+    return arrow::Status::OK();
+  }
+
+  arrow::Status Read(int64_t nbytes, int64_t* bytes_read, uint8_t* out) {
+    assert(0);
+    return arrow::Status::OK();
+  }
+
+  arrow::Status Seek(int64_t position) override {
+    position_ = position;
+    return arrow::Status::OK();
+  }
+
+  arrow::Status Close() override {
+    return arrow::Status::OK();
+  }
+
+  arrow::Status Tell(int64_t* position) override {
+    *position = position_;
+    return arrow::Status::OK();
+  }
+
+  arrow::Status Write(const uint8_t* data, int64_t nbytes) override {
+    DCHECK(position_ >= 0 && position_ < size_);
+    DCHECK(position_ + nbytes <= size_) << "position: " << position_ << " nbytes: " << nbytes << "size: " << size_;
+    uint8_t* dst = data_ + position_;
+    memcpy(dst, data, nbytes);
+    position_ += nbytes;
+    return arrow::Status::OK();
+  }
+
+  arrow::Status GetSize(int64_t *size) override {
+    *size = size_;
+    return arrow::Status::OK();
+  }
+
+  bool supports_zero_copy() const override {
+    return true;
+  }
+
+private:
+ uint8_t* data_;
+ int64_t position_;
+ int64_t size_;
+};
+
+} // namespace numbuf
+
+#endif // PYNUMBUF_MEMORY_H