.. _program_listing_file_src_flamegpu_simulation_detail_DeviceStrings.cu:

Program Listing for File DeviceStrings.cu
=========================================

|exhale_lsh| :ref:`Return to documentation for file <file_src_flamegpu_simulation_detail_DeviceStrings.cu>` (``src/flamegpu/simulation/detail/DeviceStrings.cu``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   #include "flamegpu/simulation/detail/DeviceStrings.h"
   
   #include <string>
   
   #include "flamegpu/detail/cuda.cuh"
   #include "flamegpu/simulation/detail/CUDAErrorChecking.cuh"
   
   namespace flamegpu {
   namespace detail {
   
   DeviceStrings::~DeviceStrings() {
       gpuErrchk(detail::cuda::cudaFree(device_buffer));
   }
   void DeviceStrings::registerDeviceString(const std::string &host_string) {
       if (offsets.find(host_string) == offsets.end()) {
           offsets.emplace(host_string, host_buffer.size());
           host_stream << host_string;
           host_stream << '\0';  // Each string requires a null terminating char
           host_buffer = host_stream.str();
       }
   }
   const char* DeviceStrings::getDeviceString(const std::string &host_string) {
       if (offsets.find(host_string) == offsets.end()) {
           registerDeviceString(host_string);
       }
       const size_t host_buffer_len = host_buffer.size();
       const ptrdiff_t device_string_offset = offsets.at(host_string);
       // Reallocate device buffer if necessary
       if (!device_buffer || device_buffer_len < host_buffer_len) {
           // Double buffer len in size
           device_buffer_len = device_buffer_len == 0 ? 1024 : device_buffer_len * 2;
           gpuErrchk(cudaFree(device_buffer));
           gpuErrchk(cudaMalloc(&device_buffer, device_buffer_len));
           device_buffer_occupied = 0;
       }
       // Update device buffer if necessary
       if (device_buffer_occupied < host_buffer_len) {
           gpuErrchk(cudaMemcpy(device_buffer, host_buffer.c_str(), host_buffer_len, cudaMemcpyHostToDevice));
           device_buffer_occupied = host_buffer_len;
       }
       // Return
       return device_buffer + device_string_offset;
   }
   
   }  // namespace detail
   }  // namespace flamegpu