Add util module

src/comfortable_swipe/util/autostart_filename.cpp

@@ -0,0 +1,28 @@
+#ifndef __COMFORTABLE_SWIPE__util_conf_filename__
+#define __COMFORTABLE_SWIPE__util_conf_filename__
+
+#include <string> // std::string
+#include <unistd.h> // getenv
+
+namespace comfortable_swipe::util
+{
+    /**
+     * The path where the autostart configuration is located.
+     */
+    const char* autostart_filename()
+    {
+        static std::string filename;
+        if (filename.empty()) {
+            const char* xdg_config = getenv("XDG_CONFIG_HOME");
+            std::string config(
+                xdg_config == NULL
+                    ? std::string(getenv("HOME")) + "/.config"
+                    : xdg_config
+            );
+            filename = config + "/autostart/comfortable-swipe.desktop";
+        }
+        return filename.data();
+    }
+}
+
+#endif /* __COMFORTABLE_SWIPE__util_conf_filename__ */

src/comfortable_swipe/util/conf_filename.cpp

@@ -0,0 +1,17 @@
+#ifndef __COMFORTABLE_SWIPE__util_conf_filename__
+#define __COMFORTABLE_SWIPE__util_conf_filename__
+
+#include "../index.hpp"
+
+namespace comfortable_swipe::util
+{
+    /**
+     * The path where the configuration file is located.
+     */
+    constexpr const char* conf_filename()
+    {
+        return __COMFORTABLE_SWIPE__CONFIG__;
+    }
+}
+
+#endif /* __COMFORTABLE_SWIPE__util_conf_filename__ */

src/comfortable_swipe/util/read_config_file.cpp

@@ -0,0 +1,78 @@
+#include <map> // std::map
+#include <string> // std::string
+#include <fstream> // std::ifstream
+#include <iostream> // std::cerr, std::endl, std::getline
+#include <cstdlib> // exit
+#include <cctype> // std::isspace
+
+namespace comfortable_swipe::util
+{
+    /**
+     * A utility method for reading the config file.
+     * 
+     * @param filename (const char*) the path of the config file.
+     */
+    std::map<std::string, std::string> read_config_file(const char* filename)
+    {
+        
+        std::map<std::string, std::string> conf;
+        std::ifstream fin(filename);
+
+        if (!fin.is_open())
+        {
+            std::cerr << "file \"" << filename << "\" does not exist!" << std::endl;
+            exit(1);
+        }
+
+        static std::string line, token[2];
+        int line_number = 0;
+        
+        while (std::getline(fin, line))
+        {
+            ++line_number;
+            token[0].clear();
+            token[1].clear();
+            int length = line.length();
+            int equal_flag = 0;
+            
+            // tokenize comfig config
+            for (int i = 0; i < length; ++i)
+            {
+                if (line[i] == '#') // skip comments
+                    break;
+                if (line[i] == '=') // flag equal sign
+                {
+                    if (++equal_flag > 1)
+                    {
+                        std::cerr << "error in conf file " << filename << std::endl;
+                        std::cerr << "multiple equal signs in line " << line_number << std::endl;
+                        exit(1);
+                    }
+                }
+                else if (!std::isspace(line[i]))
+                {
+                    // add to buffer
+                    token[equal_flag].push_back(line[i]);
+                }
+            }
+
+            // ignore empty lines
+            if (equal_flag == 0 && token[0].length() == 0)
+                continue;
+
+            // no equal sign found in non-empty line
+            if (equal_flag == 0)
+            {
+                std::cerr << "error in conf file: " << filename << std::endl;
+                std::cerr << "equal sign expected in line " << line_number << std::endl;
+                exit(1);
+            }
+
+            // equal sign found, add to tokens
+            if (token[1].length() > 0)
+                conf[token[0]] = token[1];
+        }
+        
+        return conf;
+    }
+}

src/comfortable_swipe/util/regex.cpp

@@ -0,0 +1,71 @@
+#ifndef __COMFORTABLE_SWIPE__util_regex__
+#define __COMFORTABLE_SWIPE__util_regex__
+
+namespace comfortable_swipe::util
+{
+    /**
+     * Regex pattern for the libinput entry for start of swipe.
+     * Extracts one match for the number of fingers used during the swipe.
+     * 
+     * eg. event15  GESTURE_SWIPE_BEGIN +34.33s 3
+     *                                          ^
+     *                                        fingers
+     */
+    const char* GESTURE_SWIPE_BEGIN_REGEX_PATTERN =
+        "^"                        // start of string
+        "[ -]event\\d+"            // event
+        "\\s+GESTURE_SWIPE_BEGIN"  // gesture
+        "\\s+\\S+"                 // timestamp
+        "\\s+(\\d+)"               // fingers
+        "\\s*$"                        // end of string
+    ;
+
+    /**
+     * Regex pattern for the libinput entry for the end of swipe.
+     * Extracts one match for the number of fingers used during the swipe.
+     * 
+     * eg. event15  GESTURE_SWIPE_END +35.03s   3
+     *                                          ^
+     *                                        fingers
+     */
+    const char* GESTURE_SWIPE_END_REGEX_PATTERN =
+        "^"                        // start of string
+        "[ -]event\\d+"            // event
+        "\\s+GESTURE_SWIPE_END"    // gesture
+        "\\s+\\S+"                 // timestamp
+        "\\s+(\\d+)"               // fingers
+        "\\s*$"                        // end of string
+    ;
+
+    // matches signed decimal numbers (eg. "6.02" "-1.1")
+    #define CF_NUMBER_REGEX "-?\\d+(?:\\.\\d+)"
+
+    // matches and extracts a space-prefixed signed fraction (eg. "-3.00/ 5.12")
+    #define CF_NUMBER_DIVISION "\\s*(" CF_NUMBER_REGEX ")/\\s*(" CF_NUMBER_REGEX ")"
+
+    /**
+     * Regex pattern for the libinput entry for during a swipe.
+     * Extracts number of fingers used and the speed (normal and accelerated) of the swipe.
+     * 
+     * eg. event15  GESTURE_SWIPE_UPDATE +34.70s    3 -0.12/ 4.99 (-0.33/13.50 unaccelerated)
+     *                                              ^    ^    ^      ^     ^
+     *                                          fingers  dx   dy    udx   udy
+     */
+    const char* GESTURE_SWIPE_UPDATE_REGEX_PATTERN =
+        "^"                                                 // start of string
+        "[ -]event\\d+"                                     // event
+        "\\s+GESTURE_SWIPE_UPDATE"                          // gesture
+        "\\s+\\S+"                                          // timestamp
+        "\\s+(\\d+)"                                        // fingers
+        "\\s+" CF_NUMBER_DIVISION                           // speed (dx/dy)
+        "\\s+\\(" CF_NUMBER_DIVISION "\\s+unaccelerated\\)" // unaccelerated speed (udx/udy)
+        "\\s*$"                                                 // end of string
+    ;
+
+    // delete macros
+    #undef CF_NUMBER_DIVISION
+    #undef CF_NUMBER_EXTRACT
+    #undef CF_NUMBER_REGEX
+}
+
+#endif /* __COMFORTABLE_SWIPE__util_regex__ */