kevingurney commented on code in PR #38020: URL: https://github.com/apache/arrow/pull/38020#discussion_r1348795130
########## matlab/src/cpp/arrow/matlab/buffer/proxy/buffer.cc: ########## @@ -0,0 +1,97 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + + +#include "arrow/matlab/buffer/proxy/buffer.h" +#include "arrow/matlab/buffer/matlab_buffer.h" +#include "arrow/matlab/error/error.h" +#include "libmexclass/proxy/ProxyManager.h" + +namespace arrow::matlab::buffer::proxy { + + Buffer::Buffer(std::shared_ptr<arrow::Buffer> buffer) : buffer{std::move(buffer)} { + + REGISTER_METHOD(Buffer, getNumBytes); + REGISTER_METHOD(Buffer, isEqual); + REGISTER_METHOD(Buffer, toMATLAB); + } + + libmexclass::proxy::MakeResult Buffer::make(const libmexclass::proxy::FunctionArguments& constructor_arguments) { + namespace mda = ::matlab::data; + using BufferProxy = proxy::Buffer; + using MatlabBuffer = arrow::matlab::buffer::MatlabBuffer; + + mda::StructArray opts = constructor_arguments[0]; + const mda::TypedArray<uint8_t> values_mda = opts[0]["Values"]; + auto buffer = std::make_shared<MatlabBuffer>(values_mda); + return std::make_shared<BufferProxy>(std::move(buffer)); + } + + std::shared_ptr<arrow::Buffer> Buffer::unwrap() { + return buffer; + } + + void Buffer::getNumBytes(libmexclass::proxy::method::Context& context) { + namespace mda = ::matlab::data; + mda::ArrayFactory factory; + auto num_bytes_mda = factory.createScalar(buffer->size()); + context.outputs[0] = num_bytes_mda; + } + + void Buffer::isEqual(libmexclass::proxy::method::Context& context) { + namespace mda = ::matlab::data; + + bool is_equal = true; + const mda::TypedArray<uint64_t> buffer_proxy_ids = context.inputs[0]; + for (const auto& buffer_proxy_id : buffer_proxy_ids) { + // Retrieve the Buffer proxy from the ProxyManager + auto proxy = libmexclass::proxy::ProxyManager::getProxy(buffer_proxy_id); + auto buffer_proxy = std::static_pointer_cast<proxy::Buffer>(proxy); + auto buffer_to_compare = buffer_proxy->unwrap(); + + if (!buffer->Equals(*buffer_to_compare)) { + is_equal = false; + break; + } + } + mda::ArrayFactory factory; + context.outputs[0] = factory.createScalar(is_equal); + } + + void Buffer::toMATLAB(libmexclass::proxy::method::Context& context) { + namespace mda = ::matlab::data; + + // If buffer->is_cpu() returns false, invoking buffer->data() may cause a crash. + // Avoid this potential crash by first invoking ViewOrCopy(buffer, memory_manager_device). + // This function tries to create a no-copy view of the buffer on the given memory + // manager device. If not possible, then ViewOrCopy copies the buffer's contents. + MATLAB_ASSIGN_OR_ERROR_WITH_CONTEXT( + auto cpu_buffer, + arrow::Buffer::ViewOrCopy(buffer, arrow::default_cpu_memory_manager()), + context, error::BUFFER_VIEW_OR_COPY_FAILED + ); + + const auto* data_begin = cpu_buffer->data(); + const auto num_bytes = cpu_buffer->size(); + // data_begin is a uint8_t*, so num_bytes is equal to the number of elements Review Comment: number of elements -> number of bytes -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
