✨Add list_files function #615

include/pros/misc.h

@@ -723,6 +723,49 @@ double battery_get_capacity(void);
  */
 int32_t usd_is_installed(void);
 
+/**
+ * Lists the files in a directory specified by the path
+ * Puts the list of file names (NOT DIRECTORIES) into the buffer seperated by newlines
+ * 
+ * This function uses the following values of errno when an error state is
+ * reached:
+ * 
+ * EIO - Hard error occured in the low level disk I/O layer
+ * EINVAL - file or directory is invalid, or length is invalid
+ * EBUSY - THe physical drinve cannot work
+ * ENOENT - cannot find the path or file
+ * EINVAL - the path name format is invalid
+ * EACCES - Access denied or directory full
+ * EEXIST - Access denied
+ * EROFS - SD card is write protected 
+ * ENXIO - drive number is invalid or not a FAT32 drive
+ * ENOBUFS - drive has no work area
+ * ENFILE - too many open files
+ * 
+ * 
+ *  
+ * \note use a path of "\" to list the files in the main directory NOT "/usd/"
+ *  DO NOT PREPEND YOUR PATHS WITH "/usd/"
+ * 
+ * \return 1 on success or PROS_ERR on failure setting errno
+ * 
+ * \b Example
+ * \code
+ * void opcontrol() {
+ * 	char* test = (char*) malloc(128);
+ *	pros::c::usd_list_files_raw("/", test, 128);
+ *	pros::delay(200);
+ *	printf("%s\n", test); //Prints the file names in the root directory seperated by newlines
+ *  pros::delay(100);
+ *  pros::c::usd_list_files_raw("/test", test, 128);
+ *	pros::delay(200);
+ *	printf("%s\n", test); //Prints the names of files in the folder named test seperated by newlines
+ *  pros::delay(100);
+ * }
+ * \endcode
+*/
+int32_t usd_list_files_raw(const char* path, char* buffer, int32_t len);
+
 /******************************************************************************/
 /**                              Date and Time                               **/
 /******************************************************************************/

include/pros/misc.hpp

@@ -26,6 +26,7 @@
 
 #include <cstdint>
 #include <string>
+#include <vector>
 
 namespace pros {
 inline namespace v5 {
@@ -525,6 +526,95 @@ namespace usd {
  * \endcode
  */
 std::int32_t is_installed(void);
+
+/**
+Lists the files in a directory specified by the path
+ * Puts the list of file names (NOT DIRECTORIES) into the buffer seperated by newlines
+ * 
+ * This function uses the following values of errno when an error state is
+ * reached:
+ * 
+ * EIO - Hard error occured in the low level disk I/O layer
+ * EINVAL - file or directory is invalid, or length is invalid
+ * EBUSY - THe physical drinve cannot work
+ * ENOENT - cannot find the path or file
+ * EINVAL - the path name format is invalid
+ * EACCES - Access denied or directory full
+ * EEXIST - Access denied
+ * EROFS - SD card is write protected 
+ * ENXIO - drive number is invalid or not a FAT32 drive
+ * ENOBUFS - drive has no work area
+ * ENFILE - too many open files
+ * 
+ * 
+ *  
+ * \note use a path of "\" to list the files in the main directory NOT "/usd/"
+ *  DO NOT PREPEND YOUR PATHS WITH "/usd/"
+ * 
+ * \return 1 on success or PROS_ERR on failure, setting errno
+ * 
+ * \b Example
+ * \code
+ * void opcontrol() {
+ * 	char* test = (char*) malloc(128);
+ *	pros::usd::list_files_raw("/", test, 128);
+ *	pros::delay(200);
+ *	printf("%s\n", test); //Prints the file names in the root directory seperated by newlines
+ *  pros::delay(100);
+ *  pros::list_files_raw("/test", test, 128);
+ *	pros::delay(200);
+ *	printf("%s\n", test); //Prints the names of files in the folder named test seperated by newlines
+ *  pros::delay(100);
+ * }
+ * \endcode
+*/
+std::int32_t list_files_raw(const char* path, char* buffer, int32_t len);
+
+/**
+Lists the files in a directory specified by the path
+ * Puts the list of file names (NOT DIRECTORIES) into the buffer seperated by newlines
+ * 
+ * This function uses the following values of errno when an error state is
+ * reached:
+ * 
+ * EIO - Hard error occured in the low level disk I/O layer
+ * EINVAL - file or directory is invalid, or length is invalid
+ * EBUSY - THe physical drinve cannot work
+ * ENOENT - cannot find the path or file
+ * EINVAL - the path name format is invalid
+ * EACCES - Access denied or directory full
+ * EEXIST - Access denied
+ * EROFS - SD card is write protected 
+ * ENXIO - drive number is invalid or not a FAT32 drive
+ * ENOBUFS - drive has no work area
+ * ENFILE - too many open files
+ * 
+ * 
+ *  
+ * \note use a path of "\" to list the files in the main directory NOT "/usd/"
+ *  DO NOT PREPEND YOUR PATHS WITH "/usd/"
+ * 
+ * \return vector of std::string of file names, if error occurs, returns vector containing
+ * one element specifying the error state
+ * 
+ * \b Example
+ * \code
+ * void opcontrol() {
+ * 	char* test = (char*) malloc(128);
+ *  // Will return vector containing names of files in root directory
+ *	std::vector<std::string> files = pros::usd::list_files("/", test, 128);
+ *	pros::delay(200);
+ *	// Given vector of std::string file names, print each file name
+ *  // Note that if there is an error, the vector will contain one element, which
+ * // is the error state
+ *  // Print each file name
+ *	for (std::string file : files) {
+ *		std::cout << file << std::endl;
+ *	}
+ * }
+ * \endcode
+*/
+std::vector<std::string> list_files(const char* path, char* buffer, int32_t len);
 }  // namespace usd
 
 }  // namespace pros

src/devices/vdml_usd.c

@@ -17,3 +17,15 @@
 int32_t usd_is_installed(void) {
 	return vexFileDriveStatus(0);
 }
+static const int FRESULTMAP[] = {0,       EIO,    EINVAL, EBUSY, ENOENT,  ENOENT, EINVAL, EACCES,  // FR_DENIED
+                                 EEXIST,  EINVAL, EROFS,  ENXIO, ENOBUFS, ENXIO,  EIO,    EACCES,  // FR_LOCKED
+                                 ENOBUFS, ENFILE, EINVAL};
+
+int32_t usd_list_files_raw(const char* path, char* buffer, int32_t len) {
+	FRESULT result =  vexFileDirectoryGet(path, buffer, len);
+	if (result != F_OK) {
+		errno = FRESULTMAP[result];
+		return PROS_ERR;
+	}
+	return PROS_SUCCESS;
+}

src/devices/vdml_usd.cpp

@@ -21,5 +21,80 @@ std::int32_t is_installed(void) {
 	return usd_is_installed();
 }
 
+std::int32_t list_files_raw(const char* path, char* buffer, int32_t len) {
+	return usd_list_files_raw(path, buffer, len);
+}
+
+std::vector<std::string> list_files(const char* path, char* buffer, int32_t len) {
+	std::vector<std::string> files = {};
+	// Call the C function
+	int32_t success = usd_list_files_raw(path, buffer, len);
+	// Check if call successful, if error return vector containing error state
+	if (success == PROS_ERR) {
+		// Check errno to see which error state occurred
+		// push back error state to files vector as std::string
+		switch (errno) {
+			case EIO:
+				files.push_back("EIO");
+				break;
+			case EINVAL:
+				files.push_back("EINVAL");
+				break;
+			case EBUSY:
+				files.push_back("EBUSY");
+				break;
+			case ENOENT:
+				files.push_back("ENOENT");
+				break;
+			case EACCES:
+				files.push_back("EACCES");
+				break;
+			case EEXIST:
+				files.push_back("EEXIST");
+				break;
+			case EROFS:
+				files.push_back("EROFS");
+				break;
+			case ENXIO:
+				files.push_back("ENXIO");
+				break;
+			case ENOBUFS:
+				files.push_back("ENOBUFS");
+				break;
+			case ENFILE:
+				files.push_back("ENFILE");
+				break;
+			default:
+				// If none of the above, will be FILE IO error
+				files.push_back("FILE I/O ERROR");
+				break;
+		}
+		return files;
+	}
+	// Parse buffer given call successful, split by '/n'
+	// Store char * buffer as std::string in str
+	// Store delimiter in std::string, '\n'
+	std::string str(buffer);
+	std::string delimiter = "\n";
+
+	// position to keep track of position in str
+	// file_name used to store each file name
+	size_t position = 0;
+	std::string file_name;
+
+	// Loop until delimiter '\n' can not be found anymore
+	while ((position = str.find(delimiter)) != std::string::npos) {
+		// file_name is the string from the beginning of str to the first '\n', excluding '\n'
+		file_name = str.substr(0, position);
+		// Add token to files vector
+		files.push_back(file_name);
+		// Erase file_name from str, would be pos + 1 if we wanted to include '\n'
+		str.erase(0, position + 1);
+	}
+
+	// return vector of file names
+	return files;
+}
+
 }  // namespace usd
 }  // namespace pros