Writing out .trl files on xml export

xml_converter/integration_tests/test_cases/animation_speed/output_xml/xml_file.xml

@@ -3,17 +3,17 @@
 </MarkerCategory>
 
 <POIs>
-<Trail  AnimSpeed="0.000000" Type="mycategory" MapID="50" TrailData="temp_name_of_trail.trl"/>
-<Trail  AnimSpeed="1.000000" Type="mycategory" MapID="50" TrailData="temp_name_of_trail.trl"/>
-<Trail  AnimSpeed="3.140000" Type="mycategory" MapID="50" TrailData="temp_name_of_trail.trl"/>
-<Trail  AnimSpeed="123.456001" Type="mycategory" MapID="50" TrailData="temp_name_of_trail.trl"/>
-<Trail  AnimSpeed="0.000000" Type="mycategory" MapID="50" TrailData="temp_name_of_trail.trl"/>
-<Trail  AnimSpeed="1.000000" Type="mycategory" MapID="50" TrailData="temp_name_of_trail.trl"/>
-<Trail  AnimSpeed="3.140000" Type="mycategory" MapID="50" TrailData="temp_name_of_trail.trl"/>
-<Trail  AnimSpeed="123.456001" Type="mycategory" MapID="50" TrailData="temp_name_of_trail.trl"/>
-<Trail  AnimSpeed="-3.140000" Type="mycategory" MapID="50" TrailData="temp_name_of_trail.trl"/>
-<Trail  AnimSpeed="-123.456001" Type="mycategory" MapID="50" TrailData="temp_name_of_trail.trl"/>
-<Trail  AnimSpeed="-3.140000" Type="mycategory" MapID="50" TrailData="temp_name_of_trail.trl"/>
-<Trail  AnimSpeed="-123.456001" Type="mycategory" MapID="50" TrailData="temp_name_of_trail.trl"/>
+<Trail  AnimSpeed="0.000000" Type="mycategory" MapID="50" TrailData="037aa160e392f1c8.trl"/>
+<Trail  AnimSpeed="1.000000" Type="mycategory" MapID="50" TrailData="037aa160e392f1c8.trl"/>
+<Trail  AnimSpeed="3.140000" Type="mycategory" MapID="50" TrailData="037aa160e392f1c8.trl"/>
+<Trail  AnimSpeed="123.456001" Type="mycategory" MapID="50" TrailData="037aa160e392f1c8.trl"/>
+<Trail  AnimSpeed="0.000000" Type="mycategory" MapID="50" TrailData="037aa160e392f1c8.trl"/>
+<Trail  AnimSpeed="1.000000" Type="mycategory" MapID="50" TrailData="037aa160e392f1c8.trl"/>
+<Trail  AnimSpeed="3.140000" Type="mycategory" MapID="50" TrailData="037aa160e392f1c8.trl"/>
+<Trail  AnimSpeed="123.456001" Type="mycategory" MapID="50" TrailData="037aa160e392f1c8.trl"/>
+<Trail  AnimSpeed="-3.140000" Type="mycategory" MapID="50" TrailData="037aa160e392f1c8.trl"/>
+<Trail  AnimSpeed="-123.456001" Type="mycategory" MapID="50" TrailData="037aa160e392f1c8.trl"/>
+<Trail  AnimSpeed="-3.140000" Type="mycategory" MapID="50" TrailData="037aa160e392f1c8.trl"/>
+<Trail  AnimSpeed="-123.456001" Type="mycategory" MapID="50" TrailData="037aa160e392f1c8.trl"/>
 </POIs>
 </OverlayData>

xml_converter/src/attribute/trail_data.cpp

@@ -3,13 +3,16 @@
 #include <stdint.h>
 
 #include <algorithm>
+#include <cstddef>
+#include <cstring>
 #include <fstream>
 #include <string>
 #include <vector>
 
 #include "../packaging_xml.hpp"
 #include "../rapid_helpers.hpp"
 #include "../rapidxml-1.13/rapidxml.hpp"
+#include "../string_helper.hpp"
 #include "waypoint.pb.h"
 
 using namespace std;
@@ -75,20 +78,72 @@ void xml_attribute_to_trail_data(
     *is_set = true;
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// djb2_hash
+//
+// A simple non cryptographic hash that we use to deterministically generate the
+// filename of the trl files.
+////////////////////////////////////////////////////////////////////////////////
+uint64_t djb2_hash(const unsigned char* str, size_t length) {
+    uint64_t hash = 5381;
+    for (size_t i = 0; i < length; i++) {
+        hash = ((hash << 5) + hash) + str[i]; /* hash * 33 + c */
+    }
+    return hash;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // trail_data_to_xml_attribute
 //
 // Converts a traildata into a fully qualified xml attribute string.
 // TODO: Write ".trl" files from data
 // TOOD: Determine a better trail path name
 ////////////////////////////////////////////////////////////////////////////////
+uint32_t trail_version_number = 0;
 string trail_data_to_xml_attribute(
     const string& attribute_name,
     XMLWriterState* state,
     const TrailData* value,
     const int* map_id_value,
     const bool* is_map_id_set) {
-    return " " + attribute_name + "=\"" + "temp_name_of_trail.trl" + "\"";
+    size_t byte_array_size = sizeof(int) + sizeof(uint32_t) + value->points_x.size() * 3 * sizeof(float);
+    unsigned char* byte_array = new unsigned char[byte_array_size];
+
+    size_t offset = 0;
+    std::memcpy(byte_array + offset, &trail_version_number, sizeof(trail_version_number));
+    offset += sizeof(trail_version_number);
+
+    std::memcpy(byte_array + offset, map_id_value, sizeof(*map_id_value));
+    offset += sizeof(*map_id_value);
+
+    for (size_t i = 0; i < value->points_x.size(); i++) {
+        std::memcpy(byte_array + offset, &value->points_x[i], sizeof(float));
+        offset += sizeof(float);
+        std::memcpy(byte_array + offset, &value->points_y[i], sizeof(float));
+        offset += sizeof(float);
+        std::memcpy(byte_array + offset, &value->points_z[i], sizeof(float));
+        offset += sizeof(float);
+    }
+
+    // Sanity check offset is where we think it should be.
+    if (offset != byte_array_size) {
+        cerr << "Found more data to write then we thought. This might mean there is a programming issue for serializing trl files." << endl;
+        cerr << "Found " << offset << " instead of " << byte_array_size << endl;
+    }
+
+    string trail_file_name = long_to_hex_string(djb2_hash(byte_array, byte_array_size)) + ".trl";
+    string trail_file_path = join_file_paths(state->filedir, trail_file_name);
+
+    ofstream trail_data_file(trail_file_path, ios::binary);
+
+    if (!trail_data_file.good()) {
+        cerr << "Error opening file. " << trail_file_path << endl;
+    }
+    trail_data_file.write(reinterpret_cast<const char*>(byte_array), byte_array_size);
+    trail_data_file.close();
+
+    delete[] byte_array;
+    return " " + attribute_name + "=\"" + trail_file_name + "\"";
 }
 
 ////////////////////////////////////////////////////////////////////////////////

xml_converter/src/packaging_xml.cpp

@@ -166,6 +166,7 @@ void write_xml_file(string xml_filepath, map<string, Category>* marker_categorie
     string tab_string;
 
     XMLWriterState state;
+    state.filedir = get_base_dir(xml_filepath);
 
     outfile.open(xml_filepath, ios::out);
 

xml_converter/src/state_structs/xml_writer_state.hpp

@@ -1,4 +1,7 @@
 #pragma once
 
+#include <string>
+
 struct XMLWriterState {
+    std::string filedir;
 };

xml_converter/src/string_helper.cpp

@@ -295,3 +295,20 @@ string join_file_paths(const string& path_a, const string& path_b) {
     }
     return output + path_b;
 }
+
+////////////////////////////////////////////////////////////////////////////////
+// long_to_hex_string
+//
+// A helper function that converts an 8 byte long into a 16 byte hex string.
+////////////////////////////////////////////////////////////////////////////////
+const char* hex_chars = "0123456789abcdef";
+std::string long_to_hex_string(uint64_t number) {
+    std::string hex_string(16, '0');
+
+    for (int i = 15; i >= 0; --i) {
+        hex_string[i] = hex_chars[number & 0xF];
+        number >>= 4;
+    }
+
+    return hex_string;
+}

xml_converter/src/string_helper.hpp

@@ -22,3 +22,5 @@ std::vector<uint8_t> base64_decode(std::string const&);
 std::string get_base_dir(std::string filepath);
 bool has_suffix(std::string const& fullString, std::string const& ending);
 std::string join_file_paths(const std::string& path_a, const std::string& path_b);
+
+std::string long_to_hex_string(uint64_t number);