updated readme

only test one function per unit test file.

.gitignore

@@ -1,2 +1,5 @@
-a.out
+icscli
 .gitconfig
+*.o
+*.out
+tags

README.md

@@ -1,29 +1,57 @@
-Show upcoming events of an .ics file.
+## ics_cli
+
+#### use case
+
+- show upcoming events of an .ics file
+- insert events in your calendar
 
-```
-make run
-```
 
 #### installation
 
 ```
-make
+cd src/builddir
 ``` 
 
 ```
-sudo make install
+meson compile
 ```
 
+```
+meson install
+```
+
+#### usage
+
+the default path is for evolution ics files at `~/.local/share/evolution/calendar/system/calendar.ics`
+```
+icscli
+```
+
+for a custom path
+```
+icscli -f path/to/ics/file.ics
+```
+
+```
+icscli -h
+```
+
+
 #### uninstall
 
 ```
-sudo make uninstall
+sudo rm -f /usr/local/bin/icscli
 ```
 
+#### git-hooks for ctags pre-commit
+
+The developer has to actively enable git hooks:
+```
+git config --local core.hooksPath git-hooks
+```
+This will run `ctags` on every commit.
+
 #### TODO
 
-- change member date to start_date
+- improve and automate unit testing
-- include member end_date
+- add cli argument that will not show ongoing events, only upcoming events
-- use strftime function in pretty_print_date_time function?
-- improve makefile
-- tests

docs/ics_format.txt

@@ -0,0 +1,79 @@
+RFC5545
+-------
+https://www.rfc-editor.org/rfc/rfc5545
+
+The iCalendar object is organized into individual lines of text,
+called content lines. Content lines are delimited by a line break,
+which is a CRLF sequence (CR character followed by LF character).
+
+Lines of text SHOULD NOT be longer than 75 octets, excluding the line
+break.  Long content lines SHOULD be split into a multiple line
+representations using a line "folding" technique.  That is, a long
+line can be split between any two characters by inserting a CRLF
+immediately followed by a single linear white-space character (i.e.,
+SPACE or HTAB).  Any sequence of CRLF followed immediately by a
+single linear white-space character is ignored (i.e., removed) when
+processing the content type.
+
+For example, the line:
+
+ DESCRIPTION:This is a long description that exists on a long line.
+
+Can be represented as:
+
+ DESCRIPTION:This is a lo
+  ng description
+   that exists on a long line.
+
+The process of moving from this folded multiple-line representation
+to its single-line representation is called "unfolding".  Unfolding
+is accomplished by removing the CRLF and the linear white-space
+character that immediately follows.
+
+When parsing a content line, folded lines MUST first be unfolded
+according to the unfolding procedure described above.
+
+--------------------------------------------------------------------------------
+
+Colons seem to be allowed in the "value" so you can't split by colon.
+You have to split by "\r\n" but unfold the lines before.
+
+Observation of different ics files from different sources
+---------------------------------------------------------
+
+ICS files from Microsoft Outlook differ from those that were created by Gnome Evolution.
+The order of "fields" seems not be standardized and differs between every application.
+
+
+Evolution
+---------
+all line endings are \r\n
+
+all day event:
+DTSTART;VALUE=DATE:20230908
+DTEND;VALUE=DATE:20230909
+
+an all day event can span over multiple days and look like this:
+DTSTART;VALUE=DATE:20230911^M$
+DTEND;VALUE=DATE:20230916^M$
+
+The DTEND of an all day event is exclusively, it is not an all day event anymore!
+
+appointment:
+DTSTART;TZID=/freeassociation.sourceforge.net/Continent/City:
+ 20230909T090000
+DTEND;TZID=/freeassociation.sourceforge.net/Continent/City:
+ 20230909T093000
+
+appointments can also span over multiple days:
+DTSTART;TZID=/freeassociation.sourceforge.net/Europe/Berlin:
+ 20230913T230000
+DTEND;TZID=/freeassociation.sourceforge.net/Europe/Berlin:
+ 20230914T040000
+
+SEQUENCE is the number of times the event was modified.
+Evolution sets this to 2 after it has been generated.
+
+Appointments include the continent and city of the used time zone.
+
+"DESCRIPTION:" is an optional field.

git-hooks/pre-commit

@@ -0,0 +1,29 @@
+#!/bin/bash
+
+# make a dir called git-hooks in the top level of your repo
+# put the following line in a Readme.md:
+# git config --local core.hooksPath git-hooks
+# the user has to actively enable git hooks
+# this script has to be named "pre-commit" and should be placed
+# in the core.hooksPath
+
+if type ctags &>> /dev/null; then
+        ctags_installed=1
+else
+        ctags_installed=0
+fi
+
+if ! (( ${ctags_installed} )); then
+	printf "Ctags is not installed! Git hooks are enabled and can only be executed if it is installed.\n"
+	printf "Commit was aborted.\n"
+	exit 1
+fi
+
+if ! ctags -R src/.; then
+	printf "Ctags failed.\n\n"
+	exit 1
+else
+	printf "Ctags was successfully executed.\n"
+fi
+
+exit 0

makefile

@@ -1,32 +0,0 @@
-all:
-	gcc -Wall ./src/*.c
-
-.PHONY: debug
-debug:
-	gcc -Wall -g ./src/*.c
-	gdb a.out
-
-.PHONY: run
-run:
-	gcc -Wall ./src/*.c
-	./a.out
-
-.PHONY: install
-install: a.out
-	cp a.out /usr/local/bin/ics_analyzer
-
-.PHONY: clean
-clean:
-	rm a.out
-
-.PHONY: uninstall
-uninstall:
-	rm /usr/local/bin/ics_analyzer
-
-.PHONY: test
-test:
-	./a.out
-	@echo
-	./a.out -h
-	@echo
-	./a.out -f tests/calendar.ics

src/cli_arg_parsing.c

@@ -1,3 +1,4 @@
+#include "insert_event.h"
 #include "cli_arg_parsing.h"
 #include <stdio.h>
 #include <stdlib.h>
@@ -5,37 +6,42 @@
 #include <string.h>
 
 void usage() {
-  printf ("-h\tprint this help\n");
+	printf ("-a\t\t\tshow all upcoming events (default is 5 events)\n");
-  printf ("-f\tspecify ics file path\n");
+	printf ("-f [FILE PATH]\t\tspecify ics file path\n");
-  exit(0);
+	printf ("-h\t\t\tprint this help\n");
+	printf ("-i\t\t\tinsert an event\n");
+	exit(0);
 }
 
-void get_cli_args(int argc, char **argv, char **file_name) {
+void get_cli_args(int argc, char **argv, char **file_name, int *show_all_events) {
-  int opt = 0;
+	int opt = 0;
 
-  memset(file_name, '\0', strlen(*file_name));
+	memset(file_name, '\0', strlen(*file_name));
 
-  if (argc < 2) {
+	char *home = getenv("HOME");
-    char *home = getenv("HOME");
+	*file_name = home;
-    *file_name = home;
 
-    if (home != NULL) {
+	if (home != NULL) {
-      strcat(*file_name, "/.local/share/evolution/calendar/system/calendar.ics");
+	  strcat(*file_name, "/.local/share/evolution/calendar/system/calendar.ics");
-    } else {
+	} else {
-      printf ("Environment variable HOME is not set.\n");
+	  printf ("Environment variable HOME is not set.\n");
-      exit(1);
+	  exit(1);
-    }
+	}
-    return;
-  }
 
-  while ((opt = getopt(argc, argv, "f:h")) != -1) {
+	while ((opt = getopt(argc, argv, "f:ahi")) != -1) {
-    switch(opt) {
+    	switch(opt) {
-      case 'f':
+			case 'a':
-      *file_name = optarg;
+			*show_all_events = 1;
-      break;
+			break;
-      case 'h':
+			case 'f':
-      usage();
+			*file_name = optarg;
-    }
+			break;
-  }
+			case 'h':
+			usage();
+			break;
+			case 'i':
+			insert_event(*file_name);
+			break;
+    	}
+	}
 }
-

src/cli_arg_parsing.h

@@ -2,4 +2,4 @@
 
 void usage();
 
-void get_cli_args(int argc, char **argv, char **file_name);
+void get_cli_args(int argc, char **argv, char **file_name, int *show_all_events);

src/cut_string.c

@@ -1,41 +0,0 @@
-// cut a string into two parts by the first occurence of delimiter
-// and choose the first part (side 0) or the second part (side 1)
-// the chosen part will overwrite the original string
-
-// cut a string into two parts by delimiter
-// and choose the first part (side 0) or the second part (side 1)
-// the chosen part will overwrite the original string
-
-#include <string.h>
-
-void cut_string(char my_string[], char delimiter, int side) {
-	char part1[256] = "";
-	char part2[256] = "";
-
-	int split = 0;
-
-	int j = 0;
-	for (int i = 0; i < strlen(my_string); i++) {
-		if (my_string[i] == delimiter) {
-			if (split == 0) {
-				split = 1;
-				continue;
-			}
-		}
-
-		if (split == 0) {
-			part1[i] = my_string[i];
-		} else {
-			part2[j] = my_string[i];
-			j++;
-		}
-	}
-
-	memset(my_string, '\0', strlen(my_string));
-	if (side == 0) {
-		strcpy(my_string, part1);
-	} else {
-		strcpy(my_string, part2);
-	}
-}
-

src/cut_string.h

@@ -1,5 +0,0 @@
-#pragma once
-
-// cut string into two parts and choose one part
-// side is 0 or 1
-void cut_string(char my_string[], char delimiter, int side);

src/date_time_handling.c

@@ -1,26 +1,182 @@
 #include "date_time_handling.h"
+#include "string_handling.h"
 #include <stdio.h>
-#include <time.h>
+#include <stdlib.h>
 #include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <assert.h>
 
-void get_date(char buffer[]) {
+// buffer needs to contain a string with a strlen of 15 (format: "xxxxxxxxTxxxxxx")
+// or a strlen of 16 (format: "YYYYmmddTHHMMSSZ")
+void get_date (char buffer[]) {
 	// add 1 because strlen does not include the null character
-	size_t buffer_size = strlen(buffer) + 1;
+	size_t buffer_size = strlen (buffer) + 1;
-	time_t my_unix_ts = time(NULL);
+	time_t my_unix_ts = time (NULL);
-	struct tm* my_tm_local = localtime(&my_unix_ts);
+	struct tm* my_tm_local = localtime (&my_unix_ts);
-	strftime(buffer, buffer_size, "%Y%m%dT%H%M%S", my_tm_local);
+	if (strlen (buffer) == 15) {
+		strftime (buffer, buffer_size, "%Y%m%dT%H%M%S", my_tm_local);
+	}
+	else if (strlen (buffer) == 16) {
+		strftime (buffer, buffer_size, "%Y%m%dT%H%M%SZ", my_tm_local);
+	}
 }
 
 // 20230823T194138 -> 2023-08-23 19:41:38
-void pretty_print_date_time(char date_time[]) {
+// 20230823T194138Z -> 2023-08-23 19:41:38
-	char *date = strtok(date_time, "T");
+// 20241209 -> 2024-12-09
-	char *time = strtok(NULL, "T");
+// caller has to free() the returned char array
-	printf ("%c%c%c%c-", date[0], date[1], date[2], date[3]);
+char* pretty_date_time (char date_time[]) {
-	printf ("%c%c-", date[4], date[5]);
+	// need one more char in the char pointer for null-termination
-	printf ("%c%c", date[6], date[7]);
+	int pdt_len = 20;
-	if (time != NULL) {
+	if (!strchr (date_time, 'T')) {
-		printf (" %c%c:", time[0], time[1]);
+		pdt_len = 11;
-		printf ("%c%c:", time[2], time[3]);
+	}
-		printf ("%c%c", time[4], time[5]);
+
+	char* pretty_dt = malloc (pdt_len);
+	memset(pretty_dt, '\0', pdt_len);
+	int dt_counter = 0;
+
+	if (!strcmp(date_time, "")) {
+		return pretty_dt;
+	}
+
+	for (int i = 0; i < (pdt_len-1); i++) {
+		if (i == 4 || i == 7) {
+			pretty_dt[i] = '-';
+			continue;
+		}
+		if (i == 13 || i == 16) {
+			pretty_dt[i] = ':';
+			continue;
+		}
+
+		if (date_time[dt_counter] == 'T') {
+			pretty_dt[i] = ' ';
+		} else {
+			pretty_dt[i] = date_time[dt_counter];
+		}
+		dt_counter++;
+	}
+
+	// null-terminate string
+	pretty_dt[strlen(pretty_dt)] = '\0';
+
+	return pretty_dt;
+}
+
+void pretty_print_date_time (char date_time[]) {
+	char* pdt = pretty_date_time(date_time);
+
+	printf("%s", pdt);
+
+	free(pdt);
+}
+
+void marshall_date_time (char date_time[]) {
+	char transformed_string[strlen (date_time)];
+	int j = 0;
+	remove_nl_and_cr (date_time);
+	for (int i = 0; i <= strlen (date_time); i++) {
+		if (date_time[i] != ':' && date_time[i] != '-') {
+			if (date_time[i] == ' ') {
+				transformed_string[j] = 'T';
+			}
+			else {
+				transformed_string[j] = date_time[i];
+			}
+
+			j++;
+		}
+
+	}
+	memset (date_time, '\0', strlen (date_time));
+	strcpy (date_time, transformed_string);
+}
+
+void print_end_date (char end_date[], char start_date[]) {
+	time_t start_uts = transform_date_to_unix_ts (start_date);
+	time_t end_uts = transform_date_to_unix_ts (end_date);
+	double time_difference = difftime (end_uts, start_uts);
+
+	// end_date is all day event
+	if (strlen (end_date) == 8) {
+		if (time_difference == 86400) {
+			return;
+		}
+		else {
+			printf (" - ");
+			end_uts -= 86400;
+			char* end_date_minus_one =
+				transform_unix_ts_to_date (end_uts);
+			pretty_print_date_time (end_date_minus_one);
+			free (end_date_minus_one);
+			return;
+		}
+	}
+	else {
+		// end_date is not an all day event
+
+		char* end_date_chunk = strtok (end_date, "T");
+		char* end_time_chunk = strtok (NULL, "T");
+		char* start_date_chunk = strtok (start_date, "T");
+
+		printf (" - ");
+
+		// only print the end date if it is not the same as the start date
+		if (strcmp (start_date_chunk, end_date_chunk) != 0) {
+			printf ("%c%c%c%c-", end_date_chunk[0],
+				end_date_chunk[1], end_date_chunk[2],
+				end_date_chunk[3]);
+			printf ("%c%c-", end_date_chunk[4],
+				end_date_chunk[5]);
+			printf ("%c%c ", end_date_chunk[6],
+				end_date_chunk[7]);
+		}
+
+		printf ("%c%c:", end_time_chunk[0], end_time_chunk[1]);
+		printf ("%c%c:", end_time_chunk[2], end_time_chunk[3]);
+		printf ("%c%c", end_time_chunk[4], end_time_chunk[5]);
 	}
 }
+
+// YYYYmmdd -> unix timestamp
+time_t transform_date_to_unix_ts (char date_str[]) {
+	time_t unix_stamp = 0;
+	int date_only = atoi (date_str);
+	struct tm my_tm = { 0 };
+	my_tm.tm_year = date_only / 10000 - 1900;
+	my_tm.tm_mon = (date_only % 10000) / 100 - 1;
+	my_tm.tm_mday = date_only % 100;
+
+	unix_stamp = mktime (&my_tm);
+
+	return unix_stamp;
+}
+
+// unix timestamp -> YYYYmmdd
+// make sure to free the returned buffer
+char* transform_unix_ts_to_date (time_t unix_ts) {
+	char* date_buffer = malloc (9);
+	struct tm* my_tm;
+	my_tm = localtime (&unix_ts);
+	strftime (date_buffer, 9, "%Y%m%d", my_tm);
+
+	return date_buffer;
+}
+
+char* get_tz () {
+	char* timezone_path = malloc (256);
+	ssize_t bytes_read = readlink ("/etc/localtime", timezone_path, 255);
+
+	if (bytes_read != -1) {
+		// Null-terminate the string
+		timezone_path[bytes_read] = '\0';
+	}
+	else {
+		perror ("readlink");
+		exit (1);
+	}
+
+	return timezone_path;
+}

src/date_time_handling.h

@@ -1,5 +1,13 @@
+#pragma once
+
 #include <time.h>
 #include <string.h>
 
 void get_date(char buffer[]);
+char *get_tz();
+char* pretty_date_time(char date_time[]);
 void pretty_print_date_time(char date_time[]);
+void marshall_date_time(char date_time[]);
+void print_end_date(char end_date[], char start_date[]);
+time_t transform_date_to_unix_ts(char date_str[]);
+char *transform_unix_ts_to_date(time_t unix_ts);

src/insert_event.c

@@ -0,0 +1,187 @@
+#include "insert_event.h"
+#include "string_handling.h"
+#include "date_time_handling.h"
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <uuid/uuid.h>
+
+void insert_event(char *file_name) {
+	int myfd = open(file_name, O_RDWR);
+	int all_day_event = 0;
+	char summary_buf[256] = "SUMMARY:";
+	char *input_buffer = &summary_buf[8];
+	uuid_t uuid;
+	char uuid_str[37] = "";
+	char dtstamp[] = "YYYYmmddTHHMMSSZ";
+	char *time_zone = get_tz();
+	char *dtstart_buffer = malloc(128);
+	char *dtend_buffer = malloc(128);
+
+	remove_until_delim(time_zone, '/', 4);
+
+	printf("Insert a new event\n");
+
+	printf("Is this an all day event? [y/n] ");
+	all_day_event = binary_user_choice();
+
+	printf("SUMMARY: ");
+	fgets (input_buffer, (sizeof(summary_buf)-strlen(summary_buf)), stdin);
+
+	if (strchr(input_buffer, '\n') == NULL)
+		printf ("The input has been truncated to:\n%s\n", input_buffer);
+
+	// modify the string to have \r\n line ending
+	summary_buf[strlen(summary_buf)+1] = '\0';
+	summary_buf[strlen(summary_buf)-1] = '\r';
+	summary_buf[strlen(summary_buf)] = '\n';
+
+	uuid_generate(uuid);
+	// parse uuid to a string
+	uuid_unparse(uuid, uuid_str);
+
+	get_date(dtstamp);
+
+	get_dtstart_dtend(dtstart_buffer, all_day_event, "start");
+	marshall_date_time(dtstart_buffer);
+	form_dtstart_string(dtstart_buffer, time_zone);
+
+	get_dtstart_dtend(dtend_buffer, all_day_event, "end");
+	marshall_date_time(dtend_buffer);
+	form_dtend_string(dtend_buffer, time_zone);
+
+	seek_cal_end(myfd);
+	write(myfd, "BEGIN:VEVENT\r\n", strlen("BEGIN:VEVENT\r\n"));
+	write(myfd, "UID:", strlen("UID:"));
+	write(myfd, uuid_str, strlen(uuid_str));
+	write(myfd, "\r\n", strlen("\r\n"));
+	write(myfd, "DTSTAMP:", strlen("DTSTAMP:"));
+	write(myfd, dtstamp, strlen(dtstamp));
+	write(myfd, "\r\n", strlen("\r\n"));
+	write(myfd, dtstart_buffer, strlen(dtstart_buffer));
+	write(myfd, dtend_buffer, strlen(dtend_buffer));
+	write(myfd, "SEQUENCE:2\r\n", strlen("SEQUENCE:2\r\n"));
+	write(myfd, summary_buf, strlen(summary_buf));
+	write(myfd, "TRANSP:OPAQUE\r\n", strlen("TRANSP:OPAQUE\r\n"));
+	write(myfd, "CLASS:PUBLIC\r\n", strlen("CLASS:PUBLIC\r\n"));
+	write(myfd, "CREATED:", strlen("CREATED:"));
+	write(myfd, dtstamp, strlen(dtstamp));
+	write(myfd, "\r\n", strlen("\r\n"));
+	write(myfd, "LAST-MODIFIED:", strlen("LAST-MODIFIED:"));
+	write(myfd, dtstamp, strlen(dtstamp));
+	write(myfd, "\r\n", strlen("\r\n"));
+	write(myfd, "END:VEVENT\r\n", strlen("END:VEVENT\r\n"));
+	
+	write(myfd, "END:VCALENDAR\r\n", strlen("END:VCALENDAR\r\n"));
+
+	close(myfd);
+	free(time_zone);
+	free(dtstart_buffer);
+	free(dtend_buffer);
+
+	exit(0);
+}
+
+void seek_cal_end(int fd) {
+	char search_string[] = "END:VCALENDAR";
+	int j = 0;
+	char char_reader = '\0';
+
+	lseek(fd, -1, SEEK_END);
+
+	while(read(fd, &char_reader, 1)) {
+		// no need to compare to the null terminator of the search_string
+		if (char_reader == search_string[strlen(search_string)-j-1]) {
+			j++;
+		} else {
+			j = 0;
+		}
+		if (j == (strlen(search_string))) {
+			lseek(fd, -1, SEEK_CUR);
+			break;
+		}
+		lseek(fd, -2, SEEK_CUR);
+	}
+}
+
+int binary_user_choice() {
+	char input_buffer[64] = "";
+	if (fgets (input_buffer, sizeof(input_buffer), stdin) == NULL) {
+		printf ("an fgets error occured\n");
+	}
+	if (! strchr(input_buffer, '\n')) {
+		printf ("Input buffer overflow!\n");
+		exit(1);
+	}
+	if (input_buffer[0] == 'n' || input_buffer[0] == 'N') {
+		return 0;
+	} else if (input_buffer[0] == 'y' || input_buffer[0] == 'Y') {
+		return 1;
+	} else {
+		printf ("Please enter a N/n or Y/y character!\n");
+		exit(1);
+	}
+}
+
+// char *start_or_end should contain "start" or "end"
+void get_dtstart_dtend(char input_buffer[], int all_day_event, char *start_or_end) {
+	if (all_day_event) {
+		printf("Enter the %s date in YYYY-mm-dd format!\n", start_or_end);
+		if (fgets(input_buffer, 128, stdin) == NULL) {
+			perror ("fgets");
+			exit(1);
+		}
+		if (strlen(input_buffer) != 11) {
+			printf ("Wrong format!\n");
+			exit(1);
+		}
+	} else {
+		printf("Enter the %s date in YYYY-mm-dd HH:MM:SS format!\n", start_or_end);
+		if (fgets(input_buffer, 128, stdin) == NULL) {
+			perror ("fgets");
+			exit(1);
+		}
+		if (strlen(input_buffer) != 20) {
+			printf ("Wrong format!\n");
+			exit(1);
+		}
+	}
+}
+
+void form_dtstart_string(char dtstart_buffer[], char time_zone[]) {
+	char dtstart_copy[strlen(dtstart_buffer)];
+	strcpy(dtstart_copy, dtstart_buffer);
+
+	// not all day event
+	if (strlen(dtstart_buffer) == 15) {
+		strcpy(dtstart_buffer, "DTSTART;TZID=/freeassociation.sourceforge.net");
+		strcat(dtstart_buffer, time_zone);
+		strcat(dtstart_buffer, ":\r\n ");
+		strcat(dtstart_buffer, dtstart_copy);
+	} else {
+		// all day event
+		strcpy(dtstart_buffer, "DTSTART;VALUE=DATE:");
+		strcat(dtstart_buffer, dtstart_copy);
+	}
+	strcat(dtstart_buffer, "\r\n");
+}
+
+void form_dtend_string(char dtend_buffer[], char time_zone[]) {
+	char dtend_copy[strlen(dtend_buffer)];
+	strcpy(dtend_copy, dtend_buffer);
+
+	// not all day event
+	if (strlen(dtend_buffer) == 15) {
+		strcpy(dtend_buffer, "DTEND;TZID=/freeassociation.sourceforge.net");
+		strcat(dtend_buffer, time_zone);
+		strcat(dtend_buffer, ":\r\n ");
+		strcat(dtend_buffer, dtend_copy);
+	} else {
+		// all day event
+		strcpy(dtend_buffer, "DTEND;VALUE=DATE:");
+		strcat(dtend_buffer, dtend_copy);
+	}
+	strcat(dtend_buffer, "\r\n");
+}

src/insert_event.h

@@ -0,0 +1,8 @@
+#pragma once
+
+void insert_event(char *file_name);
+void seek_cal_end(int fd);
+int binary_user_choice();
+void get_dtstart_dtend(char input_buffer[], int all_day_event, char *start_or_end);
+void form_dtstart_string(char dtstart_buffer[], char time_zone[]);
+void form_dtend_string(char dtend_buffer[], char time_zone[]);

src/list_handling.c

@@ -6,27 +6,29 @@
 
 void print_list(struct event *head) {
   while (head != NULL) {
-    printf("%s\n", head->date);
+    printf("%s\n", head->start_date);
+    printf("%s\n", head->end_date);
     printf("%s\n", head->summary);
     head = head->next;
   }
 }
 
-void sorted_insert(struct event** head, char date[], char summary[]) {
+void sorted_insert(struct event** head, char start_date[], char end_date[], char summary[]) {
 	struct event *new_node = malloc(sizeof(struct event));
-	strcpy((*new_node).date, date);
+	strcpy((*new_node).start_date, start_date);
+	strcpy((*new_node).end_date, end_date);
 	strcpy((*new_node).summary, summary);
 
-	if (*head == NULL || strcmp((*head)->date, new_node->date) >= 0) {
+	if (*head == NULL || strcmp((*head)->start_date, new_node->start_date) >= 0) {
 		new_node->next = *head;
 		*head = new_node;
 	}
 	else {
 		// Locate the node before the point of insertion
 		struct event* current = *head;
-		while (current->next!=NULL && strcmp(current->next->date, new_node->date) < 0) {
+		while (current->next!=NULL && strcmp(current->next->start_date, new_node->start_date) < 0)
-		current = current->next;
+			current = current->next;
-	}
+	
 		new_node->next = current->next;
 		current->next = new_node;
 	}
@@ -44,12 +46,26 @@ void free_list(struct event *head)
     }
 }
 
-void print_upcoming(struct event *head, char current_date[]) {
+// print_upcoming() also prints ongoing events
+// because you usually also want to see those
+void print_upcoming(struct event *head, char current_date[], int show_all_events) {
+	int i = 0;
 	while (head != NULL) {
-		if (strcmp(head->date, current_date) >= 0) {
+		if (strcmp(head->end_date, current_date) >= 0) {
-			pretty_print_date_time(head->date);
+			pretty_print_date_time(head->start_date);
-			printf("\n%s\n", head->summary);
+			print_end_date(head->end_date, head->start_date);
+			printf("\nSUMMARY: %s\n", head->summary);
+
+			if (!show_all_events) {
+				i++;
+				if (i > 4)
+					break;
+			}
+
+			if (head->next != NULL)
+				printf("\n");
 		}
-	head = head->next;
+
+		head = head->next;
 	}
 }

src/list_handling.h

@@ -2,11 +2,12 @@
 
 struct event {
   char summary[256];
-  char date[256];
+  char start_date[256];
+  char end_date[256];
   struct event *next;
 };
 
 void print_list(struct event *head);
-void sorted_insert(struct event **head, char date[], char summary[]);
+void sorted_insert(struct event **head, char start_date[], char end_date[], char summary[]);
 void free_list(struct event *head);
-void print_upcoming(struct event *head, char current_date[]);
+void print_upcoming(struct event *head, char current_date[], int show_all_events);

src/main.c

@@ -1,68 +1,27 @@
+#include "list_handling.h"
+#include "parse_ics.h"
 #include "cli_arg_parsing.h"
 #include "date_time_handling.h"
-#include "list_handling.h"
-#include "cut_string.h"
-#include "move_lines.h"
-#include "read_until_nl.h"
-#include "read_until_string.h"
-#include "seek_string_a.h"
-#include "remove_whitespace.h"
 #include <stdio.h>
-#include <stdlib.h>
-#include <fcntl.h>
-#include <string.h>
-#include <limits.h>
 
 int main(int argc, char **argv) {
-  char *ics_path = "";
+	char *ics_path = "";
-  get_cli_args(argc, argv, &ics_path);
+	int show_all_events = 0;
 
-	char my_line[4096] = "";
+	get_cli_args(argc, argv, &ics_path, &show_all_events);
-
-	int myfd = open(ics_path, O_RDONLY);
-	if (myfd == -1) {
-		perror ("Error opening file");
-		return 1;
-	}
-
-	// initialize linked list
-	struct event *head = NULL;
 
 	static char current_date[] = "xxxxxxxxTxxxxxx";
 	get_date(current_date);
 	printf ("Current date and time: ");
 	pretty_print_date_time(current_date);
-	printf ("\n");
+	printf ("\n\n");
 
-	char date[256] = "";
+	// initialize linked list
-	char summary[256] = "";
+	struct event *head = NULL;
 
-	while(read_until_nl(myfd, my_line)) {
+	parse_ics_file(ics_path, &head);
-		if (strncmp(my_line, "BEGIN:VEVENT", 12) == 0) {
-			memset(my_line, '\0', sizeof(my_line));
-			// go to DTSTART, but dont write to a variable
-			seek_string_a(myfd, "DTSTART");
-			read_until_string(myfd, my_line, "DTEND");
-			remove_whitespace(my_line);
-			cut_string(my_line, ':', 1);
-			strcpy(date, my_line);
 
-			memset(my_line, '\0', sizeof(my_line));
+	print_upcoming(head, current_date, show_all_events);
-
-			seek_string_a(myfd, "SUMMARY:");
-			read_until_string(myfd, my_line, "TRANSP:");
-			remove_nl_and_cr(my_line);
-			strcpy(summary, my_line);
-			memset(my_line, '\0', sizeof(my_line));
-
-			sorted_insert(&head, date, summary);
-			memset(date, '\0', sizeof(date));
-			memset(summary, '\0', sizeof(summary));
-		}
-		memset(my_line, '\0', sizeof(my_line));
-	}
-
-	print_upcoming(head, current_date);
 
 	free_list(head);
 

src/meson.build

@@ -0,0 +1,5 @@
+project('ics_cli', 'c')
+
+executable('icscli', 'main.c', 'cli_arg_parsing.c', 'date_time_handling.c', 'insert_event.c', \
+'list_handling.c', 'parse_ics.c', 'read_until_nl.c', 'read_until_string.c', 'seek_string_a.c', \
+'string_handling.c', link_args : '-luuid', install: true, install_dir: '/usr/local/bin')

src/move_lines.c

@@ -1,59 +0,0 @@
-// functions that can move the file position conveniently
-// remember that the last line of a file is usually empty and goes from '\n' to EOF
-
-#include "move_lines.h"
-#include <unistd.h>
-
-// function to move back/up
-void go_back_x_lines(int fd, int lines) {
-  for (int i = 0; i < lines; i++) {
-    seek_previous_line(fd);
-  }
-}
-
-void seek_previous_line(int fd) {
-  seek_line_start(fd);
-  lseek(fd, -1, SEEK_CUR);
-  seek_line_start(fd);
-}
-
-// set file position to the beginning of the line
-void seek_line_start(int fd) {
-  char cur_char = '\0';
-
-  while (cur_char != '\n') {
-    int ret_lseek = lseek(fd, -1, SEEK_CUR);
-    if (ret_lseek == -1)
-      break;
-    
-    read(fd, &cur_char, 1);
-    if (cur_char != '\n')
-      lseek(fd, -1, SEEK_CUR);
-  }
-}
-
-// function to move forward/down
-void go_forward_x_lines(int fd, int lines) {
-  for (int i = 0; i < lines; i++) {
-    seek_next_line(fd);
-  }
-}
-
-void seek_next_line(int fd) {
-  seek_line_end(fd);
-  lseek(fd, 1, SEEK_CUR);
-}
-
-// set file position to the end of the line
-void seek_line_end(int fd) {
-  char cur_char = '\0';
-
-  while (cur_char != '\n') {
-    // return code 0 of read indicates EOF
-    if (read(fd, &cur_char, 1) == 0)
-      break;
-  }
-  
-  lseek(fd, -1, SEEK_CUR);
-}
-

src/move_lines.h

@@ -1,20 +0,0 @@
-// functions that can move the file position conveniently
-// remember that the last line of a file is usually empty and goes from '\n' to EOF
-
-#pragma once
-
-// function to move back/up
-void go_back_x_lines(int fd, int lines);
-
-void seek_previous_line(int fd);
-
-// set file position to the beginning of the line
-void seek_line_start(int fd);
-
-// function to move forward/down
-void go_forward_x_lines(int fd, int lines);
-
-void seek_next_line(int fd);
-
-// set file position to the end of the line
-void seek_line_end(int fd);

src/parse_ics.c

@@ -0,0 +1,102 @@
+#include "list_handling.h"
+#include "parse_ics.h"
+#include "read_until_nl.h"
+#include "read_until_string.h"
+#include "string_handling.h"
+#include <assert.h>
+#include <ctype.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+void parse_event(char event_string[], struct event **head) {
+	char *start_date = strstr(event_string, "\nDTSTART");
+	char *end_date = strstr(event_string, "\nDTEND");
+	char *summary = strstr(event_string, "\nSUMMARY");
+	summary = strchr(summary, ':') + 1;
+
+	char *start_date_str = malloc(256);
+	char *end_date_str = malloc(256);
+	char *summary_str = malloc(512);
+
+	memset(start_date_str, '\0', 256);
+	memset(end_date_str, '\0', 256);
+	memset(summary_str, '\0', 512);
+
+	assert(start_date != NULL);
+	assert(end_date != NULL);
+	assert(summary != NULL);
+
+	strncpy(start_date_str, start_date,
+		strchr(start_date + 1, '\n') - start_date);
+
+	strncpy(end_date_str, end_date, strchr(end_date + 1, '\n') - end_date);
+
+	strncpy(summary_str, summary, strchr(summary + 1, '\n') - summary);
+
+	// parse dates
+	remove_whitespace(start_date_str);
+	cut_string(start_date_str, ':', 1);
+
+	remove_whitespace(end_date_str);
+	cut_string(end_date_str, ':', 1);
+
+	sorted_insert(head, start_date_str, end_date_str, summary_str);
+
+	free(start_date_str);
+	free(end_date_str);
+	free(summary_str);
+}
+
+// the unfolded string has a space
+// as a separator between what where previously separate lines
+void unfolding_string(char *folded_string, char *unfolded_string) {
+	int j = 0;
+	for (int i = 0; i < strlen(folded_string); i++) {
+		if (folded_string[i] == '\r' && folded_string[i + 1] == '\n'
+		    && isblank(folded_string[i + 2])) {
+			i += 3;
+			while (isblank(folded_string[i])) {
+				i++;
+			}
+			unfolded_string[j] = ' ';
+			j++;
+			unfolded_string[j] = folded_string[i];
+			j++;
+		} else {
+			unfolded_string[j] = folded_string[i];
+			j++;
+		}
+	}
+}
+
+/* this function takes the head of an empty initialized event list
+ * and the path to the ics file
+ * it will "fill" the list
+*/
+void parse_ics_file(char *file_path, struct event **head) {
+	char my_event[8192] = "";
+	char unfolded_event[8192] = "";
+
+	int myfd = open(file_path, O_RDONLY);
+	if (myfd == -1) {
+		perror ("Error opening file");
+		exit(1);
+	}
+
+	while(read_until_nl(myfd, my_event)) {
+		if (strncmp(my_event, "BEGIN:VEVENT", 12) == 0) {
+			// include the BEGIN:EVENT to not loose the new line of first field
+			lseek(myfd, -1, SEEK_CUR);
+			memset(my_event, '\0', sizeof(my_event));
+			read_until_string(myfd, my_event, "END:VEVENT");
+			unfolding_string(my_event, unfolded_event);
+			parse_event(unfolded_event, head);
+		}
+		memset(my_event, '\0', sizeof(my_event));
+	}
+
+	close(myfd);
+}

src/parse_ics.h

@@ -0,0 +1,5 @@
+#pragma once
+
+void parse_event(char event_string[], struct event **head);
+void unfolding_string(char* folded_string, char* unfolded_string);
+void parse_ics_file(char *file_path, struct event **head);

src/remove_whitespace.c

@@ -1,45 +0,0 @@
-// this function removes all new lines and carriage returns from a string
-// you might want to write a new function that replaces '\r' and '\n'
-// with a delimiter of user's choice
-
-#include <string.h>
-
-void remove_nl_and_cr(char raw_string[]) {
-  char processed_string[strlen(raw_string)];
-
-  // counter for num of elements of processed_string
-  int j = 0;
-  for (int i = 0; i<strlen(raw_string); i++) {
-    if (raw_string[i] == '\n' || raw_string[i] == '\r') {
-      continue;
-    } else {
-      processed_string[j] = raw_string[i];
-      j++;
-    }
-  }
-  processed_string[j] = '\0';
-
-  memset(raw_string, '\0', strlen(raw_string));
-  strcpy(raw_string, processed_string);
-}
-
-// remove new lines, carriage returns and spaces
-void remove_whitespace(char raw_string[]) {
-  char processed_string[strlen(raw_string)];
-
-  // counter for num of elements of processed_string
-  int j = 0;
-  for (int i = 0; i<strlen(raw_string); i++) {
-    if (raw_string[i] == '\n' || raw_string[i] == '\r' \
-			|| raw_string[i] == ' ') {
-      continue;
-    } else {
-      processed_string[j] = raw_string[i];
-      j++;
-    }
-  }
-  processed_string[j] = '\0';
-
-  memset(raw_string, '\0', strlen(raw_string));
-  strcpy(raw_string, processed_string);
-}

src/remove_whitespace.h

@@ -1,8 +0,0 @@
-// this function removes all new lines and carriage returns from a string
-// you might want to write a new function that replaces '\r' and '\n'
-// with a delimiter of user's choice
-
-#pragma once
-
-void remove_nl_and_cr(char raw_string[]);
-void remove_whitespace(char raw_string[]);

src/string_handling.c

@@ -0,0 +1,103 @@
+// cut a string into two parts by the first occurence of delimiter
+// and choose the first part (side 0) or the second part (side 1)
+// the chosen part will overwrite the original string
+
+// cut a string into two parts by delimiter
+// and choose the first part (side 0) or the second part (side 1)
+// the chosen part will overwrite the original string
+
+#include <string.h>
+#include <stdlib.h>
+
+void cut_string(char my_string[], char delimiter, int side) {
+	char part1[256] = "";
+	char part2[256] = "";
+
+	int split = 0;
+
+	int j = 0;
+	for (int i = 0; i < strlen(my_string); i++) {
+		if (my_string[i] == delimiter) {
+			if (split == 0) {
+				split = 1;
+				continue;
+			}
+		}
+
+		if (split == 0) {
+			part1[i] = my_string[i];
+		} else {
+			part2[j] = my_string[i];
+			j++;
+		}
+	}
+
+	memset(my_string, '\0', strlen(my_string));
+	if (side == 0) {
+		strcpy(my_string, part1);
+	} else {
+		strcpy(my_string, part2);
+	}
+}
+
+// this function removes all new lines and carriage returns from a string
+// you might want to write a new function that replaces '\r' and '\n'
+// with a delimiter of user's choice
+void remove_nl_and_cr(char raw_string[]) {
+  char processed_string[strlen(raw_string)];
+
+  // counter for num of elements of processed_string
+  int j = 0;
+  for (int i = 0; i<strlen(raw_string); i++) {
+    if (raw_string[i] == '\n' || raw_string[i] == '\r') {
+      continue;
+    } else {
+      processed_string[j] = raw_string[i];
+      j++;
+    }
+  }
+  processed_string[j] = '\0';
+
+  memset(raw_string, '\0', strlen(raw_string));
+  strcpy(raw_string, processed_string);
+}
+
+// remove new lines, carriage returns and spaces
+void remove_whitespace(char raw_string[]) {
+  char processed_string[strlen(raw_string)];
+
+  // counter for num of elements of processed_string
+  int j = 0;
+  for (int i = 0; i<strlen(raw_string); i++) {
+    if (raw_string[i] == '\n' || raw_string[i] == '\r' \
+			|| raw_string[i] == ' ') {
+      continue;
+    } else {
+      processed_string[j] = raw_string[i];
+      j++;
+    }
+  }
+  processed_string[j] = '\0';
+
+  memset(raw_string, '\0', strlen(raw_string));
+  strcpy(raw_string, processed_string);
+}
+
+void remove_until_delim(char raw_string[], char delimiter, int occurence) {
+	int chunk = 0;
+	int j = 0;
+	char *tmp_string = malloc(strlen(raw_string));
+	memset(tmp_string, '\0', strlen(raw_string));
+
+	for (int i = 0; i < strlen(raw_string); i++) {
+		if (raw_string[i] == delimiter) {
+			chunk++;
+		}
+		if (chunk >= occurence) {
+			tmp_string[j] = raw_string[i];
+			j++;
+		}
+	}
+	strcpy(raw_string, tmp_string);
+	free(tmp_string);
+}

src/string_handling.h

@@ -0,0 +1,8 @@
+#pragma once
+
+// cut string into two parts and choose one part
+// side is 0 or 1
+void cut_string(char my_string[], char delimiter, int side);
+void remove_nl_and_cr(char raw_string[]);
+void remove_whitespace(char raw_string[]);
+void remove_until_delim(char raw_string[], char delimiter, int occurence);

tests/calendar.ics

@@ -301,9 +301,9 @@ BEGIN:VEVENT
 UID:ce6cc0e3ca1bb6a22783ace61034b12c57325b4e
 DTSTAMP:20230719T152822Z
 DTSTART;TZID=/freeassociation.sourceforge.net/Europe/Berlin:
- 20230831T180000
+ 20241005T140000
 DTEND;TZID=/freeassociation.sourceforge.net/Europe/Berlin:
- 20230831T220000
+ 20241005T220000
 SEQUENCE:3
 SUMMARY:dentist
 TRANSP:OPAQUE
@@ -315,9 +315,9 @@ BEGIN:VEVENT
 UID:be6dd0e3ca1bb6a44783ade61056b12c57325b5f
 DTSTAMP:20230819T152822Z
 DTSTART;TZID=/freeassociation.sourceforge.net/Europe/Berlin:
- 20240131T080000
+ 20250131T080000
 DTEND;TZID=/freeassociation.sourceforge.net/Europe/Berlin:
- 20240131T100000
+ 20250131T100000
 SEQUENCE:3
 SUMMARY:do laundry
 TRANSP:OPAQUE
@@ -325,4 +325,16 @@ CLASS:PUBLIC
 CREATED:20230819T153023Z
 LAST-MODIFIED:20230819T153034Z
 END:VEVENT
+BEGIN:VEVENT
+UID:ba584c4a-5369-4d9e-9b6f-157a3abda095
+DTSTAMP:20230917T103047Z
+DTSTART;VALUE=DATE:20250301
+DTEND;VALUE=DATE:20250308
+SEQUENCE:2
+SUMMARY:vacation
+TRANSP:OPAQUE
+CLASS:PUBLIC
+CREATED:20230917T103047Z
+LAST-MODIFIED:20230917T103047Z
+END:VEVENT
 END:VCALENDAR

tests/failed_cal.ics

@@ -0,0 +1,297 @@
+BEGIN:VCALENDAR
+CALSCALE:GREGORIAN
+PRODID:-//Ximian//NONSGML Evolution Calendar//EN
+VERSION:2.0
+X-EVOLUTION-DATA-REVISION:2024-11-06T05:14:31.539689Z(0)
+BEGIN:VTIMEZONE
+TZID:UTC
+BEGIN:STANDARD
+DTSTART;VALUE=DATE:16010101
+TZOFFSETFROM:+0000
+TZOFFSETTO:+0000
+END:STANDARD
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:Europe/Berlin
+TZURL:http://tzurl.org/zoneinfo/Europe/Berlin
+X-LIC-LOCATION:Europe/Berlin
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+TZNAME:CEST
+DTSTART:19810329T020000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+TZNAME:CET
+DTSTART:19961027T030000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+BEGIN:STANDARD
+TZOFFSETFROM:+005328
+TZOFFSETTO:+0100
+TZNAME:CET
+DTSTART:18930401T000000
+RDATE:18930401T000000
+END:STANDARD
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+TZNAME:CEST
+DTSTART:19160430T230000
+RDATE:19160430T230000
+RDATE:19170416T020000
+RDATE:19180415T020000
+RDATE:19400401T020000
+RDATE:19430329T020000
+RDATE:19440403T020000
+RDATE:19450402T020000
+RDATE:19460414T020000
+RDATE:19470406T030000
+RDATE:19480418T020000
+RDATE:19490410T020000
+RDATE:19800406T020000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+TZNAME:CET
+DTSTART:19161001T010000
+RDATE:19161001T010000
+RDATE:19170917T030000
+RDATE:19180916T030000
+RDATE:19421102T030000
+RDATE:19431004T030000
+RDATE:19441002T030000
+RDATE:19451118T030000
+RDATE:19461007T030000
+RDATE:19471005T030000
+RDATE:19481003T030000
+RDATE:19491002T030000
+RDATE:19800928T030000
+RDATE:19810927T030000
+RDATE:19820926T030000
+RDATE:19830925T030000
+RDATE:19840930T030000
+RDATE:19850929T030000
+RDATE:19860928T030000
+RDATE:19870927T030000
+RDATE:19880925T030000
+RDATE:19890924T030000
+RDATE:19900930T030000
+RDATE:19910929T030000
+RDATE:19920927T030000
+RDATE:19930926T030000
+RDATE:19940925T030000
+RDATE:19950924T030000
+END:STANDARD
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0300
+TZNAME:CEMT
+DTSTART:19450524T020000
+RDATE:19450524T020000
+RDATE:19470511T030000
+END:DAYLIGHT
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0300
+TZOFFSETTO:+0200
+TZNAME:CEST
+DTSTART:19450924T030000
+RDATE:19450924T030000
+RDATE:19470629T030000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0100
+TZNAME:CET
+DTSTART:19460101T000000
+RDATE:19460101T000000
+RDATE:19800101T000000
+END:STANDARD
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:W. Europe Standard Time
+BEGIN:STANDARD
+DTSTART:16010101T030000
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T020000
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:/freeassociation.sourceforge.net/Europe/Berlin
+X-LIC-LOCATION:Europe/Berlin
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+005328
+TZOFFSETTO:+0100
+DTSTART:18930401T000000
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19160430T230000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19161001T010000
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19170416T020000
+RRULE:FREQ=YEARLY;UNTIL=19180415T010000Z;BYDAY=3MO;BYMONTH=4
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19170917T030000
+RRULE:FREQ=YEARLY;UNTIL=19180916T010000Z;BYDAY=3MO;BYMONTH=9
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19400401T020000
+RDATE:19430329T020000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19421102T030000
+END:STANDARD
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19431004T030000
+RRULE:FREQ=YEARLY;UNTIL=19441002T010000Z;BYDAY=1MO;BYMONTH=10
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19440403T020000
+RRULE:FREQ=YEARLY;UNTIL=19450402T010000Z;BYDAY=1MO;BYMONTH=4
+END:DAYLIGHT
+BEGIN:DAYLIGHT
+TZNAME:CEMT
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0300
+DTSTART:19450524T020000
+END:DAYLIGHT
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0300
+TZOFFSETTO:+0200
+DTSTART:19450924T030000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19451118T030000
+RDATE:19461007T030000
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19460414T020000
+END:DAYLIGHT
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19470406T030000
+END:DAYLIGHT
+BEGIN:DAYLIGHT
+TZNAME:CEMT
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0300
+DTSTART:19470511T030000
+END:DAYLIGHT
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0300
+TZOFFSETTO:+0200
+DTSTART:19470629T030000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19471005T030000
+RRULE:FREQ=YEARLY;UNTIL=19491002T010000Z;BYDAY=1SU;BYMONTH=10
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19480418T020000
+RDATE:19490410T020000
+RDATE:19800406T020000
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19800928T030000
+RRULE:FREQ=YEARLY;UNTIL=19950924T010000Z;BYDAY=-1SU;BYMONTH=9
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:19810329T020000
+RRULE:FREQ=YEARLY;UNTIL=20370329T010000Z;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:19961027T030000
+RRULE:FREQ=YEARLY;UNTIL=20361026T010000Z;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+BEGIN:STANDARD
+TZNAME:CET
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+DTSTART:20371025T030000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+BEGIN:DAYLIGHT
+TZNAME:CEST
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+DTSTART:20380328T020000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VEVENT
+DTSTAMP:20251106T051352Z
+DTSTART:20251215T080000Z
+DTEND:20251215T083000Z
+SUMMARY:Interview with John Doe
+DESCRIPTION:foo
+LOCATION:teams meeting
+UID:35a4a000-dc20-47c6-b2b0-b4cbbfbb114e
+CREATED:20241106T051431Z
+LAST-MODIFIED:20241106T051431Z
+END:VEVENT
+END:VCALENDAR

tests/folded_with_spaces.ics

@@ -0,0 +1,27 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//www.example.com//iCal 4.0.3//EN
+METHOD:PUBLISH
+CALSCALE:GREGORIAN
+BEGIN:VEVENT
+CREATED:20240102T105004
+UID:ical-19709628-example-com
+DTSTART;VALUE=DATE:20250622T000000
+DTEND;VALUE=DATE:20250711T000000
+TRANSP:TRANSPARENT
+SUMMARY:vacation
+ (approved)
+  (again)
+DESCRIPTION:vacation\n\n
+ status: approved\n
+  workdays: 13,0\n\n
+   entered by: John Doe\n
+    entry date: Tue, 2024-01-02, 10:09 AM\n
+     approved on: -\n\n\n\n
+      Powered by example.com\n
+DTSTAMP:20240102T105004
+CATEGORIES:example.com
+X-MICROSOFT-CDO-BUSYSTATUS:OOF
+SEQUENCE:8
+END:VEVENT
+END:VCALENDAR

tests/folded_with_tabs.ics

@@ -0,0 +1,27 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//www.example.com//iCal 4.0.3//EN
+METHOD:PUBLISH
+CALSCALE:GREGORIAN
+BEGIN:VEVENT
+CREATED:20240102T105004
+UID:ical-19709628-example-com
+DTSTART;VALUE=DATE:20250622T000000
+DTEND;VALUE=DATE:20250711T000000
+TRANSP:TRANSPARENT
+SUMMARY:vacation
+	(approved)
+		(again)
+DESCRIPTION:vacation\n\n
+	status: approved\n
+		workdays: 13,0\n\n
+			entered by: John Doe\n
+				entry date: Tue, 2024-01-02, 10:09 AM\n
+					approved on: -\n\n\n\n
+						Powered by example.com\n
+DTSTAMP:20240102T105004
+CATEGORIES:example.com
+X-MICROSOFT-CDO-BUSYSTATUS:OOF
+SEQUENCE:8
+END:VEVENT
+END:VCALENDAR

tests/received_ical.ics

@@ -0,0 +1,19 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//www.example.com//iCal 4.0.3//EN
+METHOD:PUBLISH
+CALSCALE:GREGORIAN
+BEGIN:VEVENT
+CREATED:20240102T105004
+UID:ical-19709628-example-com
+DTSTART;VALUE=DATE:20240622T000000
+DTEND;VALUE=DATE:20240711T000000
+TRANSP:TRANSPARENT
+SUMMARY:vacation (approved)
+DESCRIPTION:vacation\n\nstatus: approved\nworkdays: 13,0\n\nentered by: John Doe\nentry date: Tue, 2024-01-02, 10:09 AM\napproved on: -\n\n\n\nPowered by example.com\n
+DTSTAMP:20240102T105004
+CATEGORIES:example.com
+X-MICROSOFT-CDO-BUSYSTATUS:OOF
+SEQUENCE:8
+END:VEVENT
+END:VCALENDAR

tests/run_tests.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+mapfile -t files < <(find ../tests/. -name "*.ics")
+
+i=1
+for file in ${files[@]}; do
+	echo "TEST ${i}: ${file}"
+	echo "===================================================="
+	../src/icscli -f "${file}"
+	echo "===================================================="
+	echo
+	((i++))
+done
+
+exit 0

tests/start_date_is_first_field.ics

@@ -0,0 +1,12 @@
+BEGIN:VCALENDAR
+BEGIN:VEVENT
+DTSTART:20240413T070000Z
+DTEND:20240413T083000Z
+DTSTAMP:20240229T171200Z
+SUMMARY:XYZ Exam (XYZ)
+DESCRIPTION:XYZ Exam (XYZ)
+UID:61792
+CREATED:20240229T171308Z
+LAST-MODIFIED:20240229T171308Z
+END:VEVENT
+END:VCALENDAR

unit-tests/meson.build

@@ -0,0 +1,16 @@
+project('ics_cli', 'c')
+
+t1e = executable('test_print_upcoming', 'test_print_upcoming.c', '../src/parse_ics.c', '../src/string_handling.c', \
+'../src/list_handling.c', '../src/date_time_handling.c', '../src/read_until_string.c', '../src/read_until_nl.c')
+
+test('test print_upcoming', t1e)
+
+t2e = executable('test_pretty_print_date_time', 'test_pretty_print_date_time.c', '../src/string_handling.c', \
+'../src/date_time_handling.c', '../src/read_until_string.c', '../src/read_until_nl.c')
+
+test('test pretty_print_date_time', t2e)
+
+t3e = executable('test_parse_ics_file', 'test_parse_ics_file.c', '../src/parse_ics.c', '../src/string_handling.c', '../src/list_handling.c', \
+'../src/date_time_handling.c', '../src/read_until_string.c', '../src/read_until_nl.c')
+
+test('test parse_ics_file', t3e)

unit-tests/test_parse_ics_file.c

@@ -0,0 +1,14 @@
+#include "../src/list_handling.h"
+#include "../src/parse_ics.h"
+#include <stdio.h>
+
+int main() {
+	// initialize empty list
+	struct event *head = NULL;
+
+	parse_ics_file("../../tests/calendar.ics", &head);
+
+	parse_ics_file("../../tests/failed_cal.ics", &head);
+
+	return 0;
+}

unit-tests/test_pretty_print_date_time.c

@@ -0,0 +1,50 @@
+#include "../src/date_time_handling.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+int main() {
+	// 1
+	char* pdt = pretty_date_time("20251215T080000Z");
+
+	assert(!strcmp(pdt, "2025-12-15 08:00:00"));
+
+	free(pdt);
+
+	// 2
+	char* pdt2 = pretty_date_time("20251215T080000");
+
+	assert(!strcmp(pdt2, "2025-12-15 08:00:00"));
+
+	free(pdt2);
+
+	// 3
+	char* pdt3 = pretty_date_time("");
+
+	assert(!strcmp(pdt3, ""));
+
+	free(pdt3);
+
+	// 4
+	char* pdt4 = pretty_date_time("20251215");
+
+	assert(!strcmp(pdt4, "2025-12-15"));
+
+	free(pdt4);
+
+	// 5
+	char current_date[] = "20240710T103000";
+
+	printf("current_date: %s\n", current_date);
+	printf("strlen(current_date): %ld\n\n", strlen(current_date));
+
+	pretty_print_date_time(current_date);
+
+	printf("\n\ncurrent_date: %s\n", current_date);
+	printf("strlen(current_date): %ld\n", strlen(current_date));
+
+	pretty_print_date_time("20251215T080000Z");
+	printf("\n");
+
+	return 0;
+}

unit-tests/test_print_upcoming.c

@@ -0,0 +1,24 @@
+#include "../src/list_handling.h"
+#include "../src/parse_ics.h"
+#include <stdio.h>
+
+int main() {
+	// initialize empty list
+	struct event *head = NULL;
+
+	// 1
+	printf("\nTesting tests/failed_cal.ics:\n\n");
+	char *current_date = "20240710T113000";
+
+	printf("DEBUG - current_date: %s\n\n", current_date);
+
+	parse_ics_file("../../tests/failed_cal.ics", &head);
+
+	print_upcoming(head, current_date, 0);
+
+	// 2
+	printf("\nTesting tests/calendar.ics:\n\n");
+	parse_ics_file("../../tests/calendar.ics", &head);
+
+	print_upcoming(head, current_date, 0);
+}