Adding in memory support for xyz files (#5866)

For Eigen datatypes

CHANGELOG.md

@@ -26,7 +26,7 @@
 -   Expose Near Clip + Far Clip parameters to setup_camera in OffscreenRenderer (#6520)
 -   Add Doppler ICP in tensor registration pipeline (PR #5237)
 -   Rename master branch to main.
-
+-   Support in memory loading of XYZ files
 
 ## 0.13
 

cpp/open3d/io/PointCloudIO.cpp

@@ -32,6 +32,16 @@ static const std::unordered_map<
                 {"pts", ReadPointCloudFromPTS},
         };
 
+static const std::unordered_map<
+        std::string,
+        std::function<bool(const unsigned char *,
+                           const size_t,
+                           geometry::PointCloud &,
+                           const ReadPointCloudOption &)>>
+        in_memory_to_pointcloud_read_function{
+                {"mem::xyz", ReadPointCloudInMemoryFromXYZ},
+        };
+
 static const std::unordered_map<
         std::string,
         std::function<bool(const std::string &,
@@ -46,6 +56,16 @@ static const std::unordered_map<
                 {"pts", WritePointCloudToPTS},
         };
 
+static const std::unordered_map<
+        std::string,
+        std::function<bool(unsigned char *&,
+                           size_t &,
+                           const geometry::PointCloud &,
+                           const WritePointCloudOption &)>>
+        in_memory_to_pointcloud_write_function{
+                {"mem::xyz", WritePointCloudInMemoryToXYZ},
+        };
+
 std::shared_ptr<geometry::PointCloud> CreatePointCloudFromFile(
         const std::string &filename,
         const std::string &format,
@@ -55,6 +75,17 @@ std::shared_ptr<geometry::PointCloud> CreatePointCloudFromFile(
     return pointcloud;
 }
 
+std::shared_ptr<geometry::PointCloud> CreatePointCloudFromMemory(
+        const unsigned char *buffer,
+        const size_t length,
+        const std::string &format,
+        bool print_progress) {
+    auto pointcloud = std::make_shared<geometry::PointCloud>();
+    ReadPointCloud(buffer, length, *pointcloud,
+                   {format, true, true, print_progress});
+    return pointcloud;
+}
+
 bool ReadPointCloud(const std::string &filename,
                     geometry::PointCloud &pointcloud,
                     const ReadPointCloudOption &params) {
@@ -104,6 +135,38 @@ bool ReadPointCloud(const std::string &filename,
     p.update_progress = progress_updater;
     return ReadPointCloud(filename, pointcloud, p);
 }
+bool ReadPointCloud(const unsigned char *buffer,
+                    const size_t length,
+                    geometry::PointCloud &pointcloud,
+                    const ReadPointCloudOption &params) {
+    std::string format = params.format;
+    if (format == "auto") {
+        utility::LogWarning(
+                "Read geometry::PointCloud failed: unknown format for "
+                "(format: {}).",
+                params.format);
+        return false;
+    }
+
+    utility::LogDebug("Format {}", params.format);
+
+    auto map_itr = in_memory_to_pointcloud_read_function.find(format);
+    if (map_itr == in_memory_to_pointcloud_read_function.end()) {
+        utility::LogWarning(
+                "Read geometry::PointCloud failed: unknown format for "
+                "(format: {}).",
+                params.format);
+        return false;
+    }
+    bool success = map_itr->second(buffer, length, pointcloud, params);
+    utility::LogDebug("Read geometry::PointCloud: {} vertices.",
+                      pointcloud.points_.size());
+    if (params.remove_nan_points || params.remove_infinite_points) {
+        pointcloud.RemoveNonFinitePoints(params.remove_nan_points,
+                                         params.remove_infinite_points);
+    }
+    return success;
+}
 
 bool WritePointCloud(const std::string &filename,
                      const geometry::PointCloud &pointcloud,
@@ -126,14 +189,17 @@ bool WritePointCloud(const std::string &filename,
 }
 bool WritePointCloud(const std::string &filename,
                      const geometry::PointCloud &pointcloud,
+                     const std::string &file_format /* = "auto"*/,
                      bool write_ascii /* = false*/,
                      bool compressed /* = false*/,
                      bool print_progress) {
     WritePointCloudOption p;
     p.write_ascii = WritePointCloudOption::IsAscii(write_ascii);
     p.compressed = WritePointCloudOption::Compressed(compressed);
-    std::string format =
-            utility::filesystem::GetFileExtensionInLowerCase(filename);
+    std::string format = file_format;
+    if (format == "auto") {
+        format = utility::filesystem::GetFileExtensionInLowerCase(filename);
+    }
     utility::ConsoleProgressUpdater progress_updater(
             std::string("Writing ") + utility::ToUpper(format) +
                     " file: " + filename,
@@ -142,5 +208,31 @@ bool WritePointCloud(const std::string &filename,
     return WritePointCloud(filename, pointcloud, p);
 }
 
+bool WritePointCloud(unsigned char *&buffer,
+                     size_t &length,
+                     const geometry::PointCloud &pointcloud,
+                     const WritePointCloudOption &params) {
+    std::string format = params.format;
+    if (format == "auto") {
+        utility::LogWarning(
+                "Write geometry::PointCloud failed: unknown format for "
+                "(format: {}).",
+                params.format);
+        return false;
+    }
+    auto map_itr = in_memory_to_pointcloud_write_function.find(format);
+    if (map_itr == in_memory_to_pointcloud_write_function.end()) {
+        utility::LogWarning(
+                "Write geometry::PointCloud failed: unknown format {}.",
+                format);
+        return false;
+    }
+
+    bool success = map_itr->second(buffer, length, pointcloud, params);
+    utility::LogDebug("Write geometry::PointCloud: {} vertices.",
+                      pointcloud.points_.size());
+    return success;
+}
+
 }  // namespace io
 }  // namespace open3d

cpp/open3d/io/PointCloudIO.h

@@ -21,6 +21,14 @@ std::shared_ptr<geometry::PointCloud> CreatePointCloudFromFile(
         const std::string &format = "auto",
         bool print_progress = false);
 
+/// Factory function to create a pointcloud from memory
+/// Return an empty pointcloud if fail to read from buffer.
+std::shared_ptr<geometry::PointCloud> CreatePointCloudFromMemory(
+        const unsigned char *buffer,
+        const size_t length,
+        const std::string &format,
+        bool print_progress = false);
+
 /// \struct ReadPointCloudOption
 /// \brief Optional parameters to ReadPointCloud
 struct ReadPointCloudOption {
@@ -43,6 +51,7 @@ struct ReadPointCloudOption {
     };
     /// Specifies what format the contents of the file are (and what loader to
     /// use), default "auto" means to go off of file extension.
+    /// Note: "auto" is incompatible when reading directly from memory.
     std::string format;
     /// Whether to remove all points that have nan
     bool remove_nan_points;
@@ -66,6 +75,15 @@ bool ReadPointCloud(const std::string &filename,
                     geometry::PointCloud &pointcloud,
                     const ReadPointCloudOption &params = {});
 
+/// The general entrance for reading a PointCloud from memory
+/// The function calls read functions based on the format.
+/// See \p ReadPointCloudOption for additional options you can pass.
+/// \return return true if the read function is successful, false otherwise.
+bool ReadPointCloud(const unsigned char *buffer,
+                    const size_t length,
+                    geometry::PointCloud &pointcloud,
+                    const ReadPointCloudOption &params = {});
+
 /// \struct WritePointCloudOption
 /// \brief Optional parameters to WritePointCloud
 struct WritePointCloudOption {
@@ -74,11 +92,13 @@ struct WritePointCloudOption {
     WritePointCloudOption(
             // Attention: when you update the defaults, update the docstrings in
             // pybind/io/class_io.cpp
+            std::string format = "auto",
             IsAscii write_ascii = IsAscii::Binary,
             Compressed compressed = Compressed::Uncompressed,
             bool print_progress = false,
             std::function<bool(double)> update_progress = {})
-        : write_ascii(write_ascii),
+        : format(format),
+          write_ascii(write_ascii),
           compressed(compressed),
           print_progress(print_progress),
           update_progress(update_progress){};
@@ -91,10 +111,25 @@ struct WritePointCloudOption {
           compressed(Compressed(compressed)),
           print_progress(print_progress),
           update_progress(update_progress){};
+    // for compatibility
+    WritePointCloudOption(std::string format,
+                          bool write_ascii,
+                          bool compressed = false,
+                          bool print_progress = false,
+                          std::function<bool(double)> update_progress = {})
+        : format(format),
+          write_ascii(IsAscii(write_ascii)),
+          compressed(Compressed(compressed)),
+          print_progress(print_progress),
+          update_progress(update_progress){};
     WritePointCloudOption(std::function<bool(double)> up)
         : WritePointCloudOption() {
         update_progress = up;
     };
+    /// Specifies what format the contents of the file are (and what writer to
+    /// use), default "auto" means to go off of file extension.
+    /// Note: "auto" is incompatible when reading directly from memory.
+    std::string format;
     /// Whether to save in Ascii or Binary.  Some savers are capable of doing
     /// either, other ignore this.
     IsAscii write_ascii;
@@ -120,14 +155,36 @@ bool WritePointCloud(const std::string &filename,
                      const geometry::PointCloud &pointcloud,
                      const WritePointCloudOption &params = {});
 
+/// The general entrance for writing a PointCloud to memory
+/// The function calls write functions based on the format.
+/// WARNING: buffer gets initialized by WritePointCloud, you need to
+/// delete it when finished when ret is true
+/// See \p WritePointCloudOption for additional options you can pass.
+/// \return return true if the write function is
+/// successful, false otherwise.
+bool WritePointCloud(unsigned char *&buffer,
+                     size_t &length,
+                     const geometry::PointCloud &pointcloud,
+                     const WritePointCloudOption &params = {});
+
 bool ReadPointCloudFromXYZ(const std::string &filename,
                            geometry::PointCloud &pointcloud,
                            const ReadPointCloudOption &params);
 
+bool ReadPointCloudInMemoryFromXYZ(const unsigned char *buffer,
+                                   const size_t length,
+                                   geometry::PointCloud &pointcloud,
+                                   const ReadPointCloudOption &params);
+
 bool WritePointCloudToXYZ(const std::string &filename,
                           const geometry::PointCloud &pointcloud,
                           const WritePointCloudOption &params);
 
+bool WritePointCloudInMemoryToXYZ(unsigned char *&buffer,
+                                  size_t &length,
+                                  const geometry::PointCloud &pointcloud,
+                                  const WritePointCloudOption &params);
+
 bool ReadPointCloudFromXYZN(const std::string &filename,
                             geometry::PointCloud &pointcloud,
                             const ReadPointCloudOption &params);

cpp/open3d/io/file_format/FileXYZ.cpp

@@ -6,10 +6,12 @@
 // ----------------------------------------------------------------------------
 
 #include <cstdio>
+#include <sstream>
 
 #include "open3d/io/FileFormatIO.h"
 #include "open3d/io/PointCloudIO.h"
 #include "open3d/utility/FileSystem.h"
+#include "open3d/utility/Helper.h"
 #include "open3d/utility/Logging.h"
 #include "open3d/utility/ProgressReporters.h"
 
@@ -54,6 +56,37 @@ bool ReadPointCloudFromXYZ(const std::string &filename,
     }
 }
 
+bool ReadPointCloudInMemoryFromXYZ(const unsigned char *buffer,
+                                   const size_t length,
+                                   geometry::PointCloud &pointcloud,
+                                   const ReadPointCloudOption &params) {
+    try {
+        utility::CountingProgressReporter reporter(params.update_progress);
+        reporter.SetTotal(static_cast<int64_t>(length));
+
+        std::string content(reinterpret_cast<const char *>(buffer), length);
+        std::istringstream ibs(content);
+        pointcloud.Clear();
+        int i = 0;
+        double x, y, z;
+        std::string line;
+        while (std::getline(ibs, line)) {
+            if (sscanf(line.c_str(), "%lf %lf %lf", &x, &y, &z) == 3) {
+                pointcloud.points_.push_back(Eigen::Vector3d(x, y, z));
+            }
+            if (++i % 1000 == 0) {
+                reporter.Update(ibs.tellg());
+            }
+        }
+        reporter.Finish();
+
+        return true;
+    } catch (const std::exception &e) {
+        utility::LogWarning("Read XYZ failed with exception: {}", e.what());
+        return false;
+    }
+}
+
 bool WritePointCloudToXYZ(const std::string &filename,
                           const geometry::PointCloud &pointcloud,
                           const WritePointCloudOption &params) {
@@ -87,5 +120,40 @@ bool WritePointCloudToXYZ(const std::string &filename,
     }
 }
 
+bool WritePointCloudInMemoryToXYZ(unsigned char *&buffer,
+                                  size_t &length,
+                                  const geometry::PointCloud &pointcloud,
+                                  const WritePointCloudOption &params) {
+    try {
+        utility::CountingProgressReporter reporter(params.update_progress);
+        reporter.SetTotal(pointcloud.points_.size());
+
+        std::string content;
+        for (size_t i = 0; i < pointcloud.points_.size(); i++) {
+            const Eigen::Vector3d &point = pointcloud.points_[i];
+            std::string line = utility::FastFormatString(
+                    "%.10f %.10f %.10f\n", point(0), point(1), point(2));
+            content.append(line);
+            if (i % 1000 == 0) {
+                reporter.Update(i);
+            }
+        }
+        // nothing to report...
+        if (content.length() == 0) {
+            reporter.Finish();
+            return false;
+        }
+        length = content.length();
+        buffer = new unsigned char[length];  // we do this for the caller
+        std::memcpy(buffer, content.c_str(), length);
+
+        reporter.Finish();
+        return true;
+    } catch (const std::exception &e) {
+        utility::LogWarning("Write XYZ failed with exception: {}", e.what());
+        return false;
+    }
+}
+
 }  // namespace io
 }  // namespace open3d

cpp/open3d/utility/Helper.h

@@ -152,6 +152,24 @@ inline std::string FormatString(const std::string& format, Args... args) {
                        buf.get() + size - 1);  // We don't want the '\0' inside
 };
 
+/// Format string fast (Unix / BSD Only)
+template <typename... Args>
+inline std::string FastFormatString(const std::string& format, Args... args) {
+#ifdef _WIN32
+    return FormatString(format, args...);
+#else
+    char* buffer = nullptr;
+    int size_s = asprintf(&buffer, format.c_str(), args...);
+    if (size_s == -1) {
+        throw std::runtime_error("Error during formatting.");
+    }
+    auto ret = std::string(buffer,
+                           buffer + size_s);  // no + 1 since we ignore the \0
+    std::free(buffer);                        // asprintf calls malloc
+    return ret;
+#endif  // _WIN32
+};
+
 void Sleep(int milliseconds);
 
 /// Computes the quotient of x/y with rounding up