Add code, Minor fixes

LICENSE.md

@@ -1,7 +1,7 @@
 "THE BEER-WARE LICENSE"
 
-Copyright (c) 2018 Apostolof, charaldp, tsakonag
+Copyright (c) 2019 Apostolof
 
 As long as you retain this notice you can do whatever you want with this stuff.
-If we meet some day, and you think this stuff is worth it, you can buy us a
+If we meet some day, and you think this stuff is worth it, you can buy me a
 beer in return.

Makefile

@@ -0,0 +1,38 @@
+SHELL := /bin/bash
+
+# ============================================
+# COMMANDS
+
+CC = gcc -std=gnu99
+RM = rm -f
+CFLAGS_DEBUG=-O2 -ggdb3 -Wall -Werror -pedantic -D_FORTIFY_SOURCE=2 -fasynchronous-unwind-tables -grecord-gcc-switches -Werror=implicit-function-declaration -I.
+CFLAGS=-O2 -Wall -Werror -pedantic -I.
+
+OBJ=test_sample.o test_sample_functions.o
+DEPS=test_sample_functions.h
+
+# ==========================================
+# TARGETS
+
+EXECUTABLES = test_sample.out
+
+.PHONY: all clean
+
+all: $(EXECUTABLES)
+
+# ==========================================
+# DEPENDENCIES (HEADERS)
+
+%.o: %.c $(DEPS)
+	$(CC) -c -o $@ $< $(CFLAGS)
+
+.PRECIOUS: $(EXECUTABLES) $(OBJ)
+
+# ==========================================
+# EXECUTABLE (MAIN)
+
+$(EXECUTABLES): $(OBJ)
+	$(CC) -o $@ $^ $(CFLAGS)
+
+clean:
+	$(RM) *.o *~ $(EXECUTABLES)

README.md

@@ -15,7 +15,7 @@ make
 ```
 and then run using:
 ```sh
-./testSample [-t time] [-d delta] [-o output]
+./test_sample [-t time] [-d delta] [-o output]
 ```
 where:
 

test_sample.c

@@ -0,0 +1,43 @@
+#include "test_sample_functions.h"
+
+int main(int argc, char **argv) {
+	Parameters parameters;
+	parseArguments(argc, argv, &parameters);
+	//parameters.numberOfSamples = (parameters.time + parameters.delta - 1) / parameters.delta;
+	parameters.numberOfSamples = 1 + ((parameters.time - 1) / parameters.delta);
+
+	// Initialize a matrix to store the sample values
+	double **samplesMatrix = (double **) malloc(parameters.numberOfSamples * sizeof(double *));
+	for (int i=0; i<parameters.numberOfSamples; ++i) {
+		samplesMatrix[i] = (double *) malloc(3 * sizeof(double));
+	}
+
+	// Saves information about the experiment to the output file
+	{
+		FILE *outputFile;
+		outputFile = fopen(parameters.outputFilename, "w");
+
+		if (outputFile == NULL) {
+			printf("Error while opening the output file.\n");
+			exit(EXIT_FAILURE);
+		}
+
+		fprintf(outputFile, "Sampling experiment will run for %f seconds\n"\
+			"Sampling period is set to %f seconds.\n"\
+			"Number of samples should be %d.\n\n",
+			parameters.time, parameters.delta, parameters.numberOfSamples);
+
+		fclose(outputFile);
+	}
+
+	printf(ANSI_COLOR_BLUE "\n----- STARTING EXPERIMENT -----\n" ANSI_COLOR_RESET);
+
+	testSampling(&samplesMatrix, parameters);
+
+	printf(ANSI_COLOR_YELLOW "\n----- WRITING RESULTS TO OUTPUT FILE -----\n" ANSI_COLOR_RESET);
+
+	// Saves results to the output file
+	saveSamplesToFile(parameters.outputFilename, samplesMatrix, parameters.numberOfSamples);
+
+	printf(ANSI_COLOR_GREEN "\n----- DONE -----\n" ANSI_COLOR_RESET);
+}

test_sample_functions.c

@@ -0,0 +1,187 @@
+/* ===== INCLUDES ===== */
+
+#include "test_sample_functions.h"
+
+/* ===== CONSTANTS ===== */
+
+const char *ARGUMENT_TIME = "-t";
+const char *ARGUMENT_DELTA = "-d";
+const char *ARGUMENT_OUTPUT_FILENAME = "-o";
+
+char *DEFAULT_OUTPUT_FILENAME = "sample_test_output";
+
+/* ===== STRUCTURES ===== */
+
+struct timeval startwtime, endwtime;
+
+/* ===== OTHER ===== */
+
+volatile sig_atomic_t sample_flag = false;
+
+/* ===== FUNCTIONS ===== */
+
+/*
+ * testSampling implements the sampling experiment. Three different ways of sampling are
+ * implemented. On the first one sleep is used. On the second sleep is used and the sleep times are
+ * corrected based on the previous error. On the third alarms are used.
+*/
+void testSampling(double ***samplesMatrix, Parameters parameters) {
+	printf(ANSI_COLOR_CYAN "\n----- RUNNING FIRST EXPERIMENT -----\n" ANSI_COLOR_RESET);
+	for (int i = 0; i < parameters.numberOfSamples; ++i) {
+		gettimeofday (&startwtime, NULL);
+
+		usleep(parameters.delta * 1000000);
+
+		gettimeofday (&endwtime, NULL);
+		(*samplesMatrix)[i][0] = (double)((endwtime.tv_usec - startwtime.tv_usec)/1.0e6 +
+			endwtime.tv_sec - startwtime.tv_sec);
+	}
+
+	printf(ANSI_COLOR_CYAN "\n----- RUNNING SECOND EXPERIMENT -----\n" ANSI_COLOR_RESET);
+	double totalError = 0;
+	for (int i = 0; i < parameters.numberOfSamples; ++i) {
+		gettimeofday (&startwtime, NULL);
+
+		usleep((parameters.delta - (totalError / (i + 1))) * 1000000);
+
+		gettimeofday (&endwtime, NULL);
+		(*samplesMatrix)[i][1] = (double)((endwtime.tv_usec - startwtime.tv_usec)/1.0e6 +
+			endwtime.tv_sec - startwtime.tv_sec);
+
+		totalError += (*samplesMatrix)[i][1] - parameters.delta;
+	}
+
+	printf(ANSI_COLOR_CYAN "\n----- RUNNING THIRD EXPERIMENT -----\n" ANSI_COLOR_RESET);
+	signal(SIGALRM, handle_alarm);
+
+	struct itimerval new;
+
+	new.it_interval.tv_usec = (int) ((parameters.delta - ((int) parameters.delta)) * 1000000);
+	new.it_interval.tv_sec = ((int) parameters.delta);
+	new.it_value.tv_usec = (int) ((parameters.delta - ((int) parameters.delta)) * 1000000);
+	new.it_value.tv_sec = ((int) parameters.delta);
+
+	if (setitimer (ITIMER_REAL, &new, NULL) == -1) {
+		perror("setitimer");
+		exit(EXIT_FAILURE);
+	}
+
+	gettimeofday (&startwtime, NULL);
+
+	int i = 0 ;
+	while(i < parameters.numberOfSamples) {
+		if (sample_flag) {
+			sample_flag = false;
+			gettimeofday (&endwtime, NULL);
+			(*samplesMatrix)[i][2] = (double)((endwtime.tv_usec - startwtime.tv_usec)/1.0e6 +
+				endwtime.tv_sec - startwtime.tv_sec);
+
+			++i;
+			gettimeofday (&startwtime, NULL);
+		}
+	}
+	//alarm(0); Is this needed?
+}
+
+void handle_alarm(int sig) {
+	sample_flag = true;
+}
+
+
+// ==================== PROGRAM INPUT AND OUTPUT UTILS ====================
+
+/*
+ * parseArguments parses the command line arguments given by the user.
+*/
+void parseArguments(int argumentCount, char **argumentVector, Parameters *parameters) {
+	if (argumentCount > 7) {
+		validUsage(argumentVector[0]);
+	}
+
+	(*parameters).time = 7200;
+	(*parameters).delta = 0.1;
+	(*parameters).outputFilename = DEFAULT_OUTPUT_FILENAME;
+
+	char *endPointer;
+	int argumentIndex = 1;
+
+	while (argumentIndex < argumentCount) {
+		if (!strcmp(argumentVector[argumentIndex], ARGUMENT_TIME)) {
+			argumentIndex = checkIncrement(argumentIndex, argumentCount, argumentVector[0]);
+
+			double timeInput = strtod(argumentVector[argumentIndex], &endPointer);
+			if ((timeInput <= 0) && endPointer) {
+				printf("Invalid time argument\n");
+				exit(EXIT_FAILURE);
+			}
+			(*parameters).time = timeInput;
+		} else if (!strcmp(argumentVector[argumentIndex], ARGUMENT_DELTA)) {
+			argumentIndex = checkIncrement(argumentIndex, argumentCount, argumentVector[0]);
+
+			double deltaInput = strtod(argumentVector[argumentIndex], &endPointer);
+			if ((deltaInput <= 0) && endPointer) {
+				printf("Invalid time argument\n");
+				exit(EXIT_FAILURE);
+			}
+			(*parameters).delta = deltaInput;
+		} else if (!strcmp(argumentVector[argumentIndex], ARGUMENT_OUTPUT_FILENAME)) {
+			argumentIndex = checkIncrement(argumentIndex, argumentCount, argumentVector[0]);
+
+			if (fopen(argumentVector[argumentIndex], "w") == NULL) {
+				printf("Invalid output filename. Reverting to default.\n");
+				continue;
+			}
+			(*parameters).outputFilename = argumentVector[argumentIndex];
+		} else {
+			validUsage(argumentVector[0]);
+			exit(EXIT_FAILURE);
+		}
+		++argumentIndex;
+	}
+}
+
+/*
+ * validUsage outputs a message to the console that informs the user of the
+ * correct (valid) way to use the program.
+*/
+void validUsage(char *programName) {
+	printf("%s [-t time] [-d delta] [-o output]" \
+		"\n-t time" \
+		"\n\ttotal duration of the sampling in seconds" \
+		"\n-d delta" \
+		"\n\tsampling period in seconds" \
+		"\n-o output" \
+		"\n\tfilename and path for the output" \
+		"\n", programName);
+	exit(EXIT_FAILURE);
+}
+
+/*
+ * checkIncrement is a helper function for parseArguments function.
+*/
+int checkIncrement(int previousIndex, int maxIndex, char *programName) {
+	if (previousIndex == maxIndex) {
+		validUsage(programName);
+		exit(EXIT_FAILURE);
+	}
+	return ++previousIndex;
+}
+
+void saveSamplesToFile(char *filename, double **samplesMatrix, int matrixRows) {
+	FILE *outputFile;
+
+	outputFile = fopen(filename, "a");
+
+	if (outputFile == NULL) {
+		printf("Error while opening the output file.\n");
+		return;
+	}
+
+	// Saves the samples matrix
+	for (int i=0; i<matrixRows; ++i) {
+		fprintf(outputFile, "%.10g\t%.10g\t%.10g\n",
+			samplesMatrix[i][0], samplesMatrix[i][1], samplesMatrix[i][2]);
+	}
+
+	fclose(outputFile);
+}

test_sample_functions.h

@@ -0,0 +1,65 @@
+#ifndef TEST_SAMPLE_FUNCTIONS_H	/* Include guard */
+#define TEST_SAMPLE_FUNCTIONS_H
+
+/* ===== INCLUDES ===== */
+
+#include <sys/time.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+#include <stdbool.h>
+
+/* ===== DEFINITIONS ===== */
+
+//Colors used for better console output formating.
+#define ANSI_COLOR_RED     "\x1B[31m"
+#define ANSI_COLOR_GREEN   "\x1B[32m"
+#define ANSI_COLOR_YELLOW  "\x1B[33m"
+#define ANSI_COLOR_BLUE    "\x1B[34m"
+#define ANSI_COLOR_CYAN    "\x1B[36m"
+#define ANSI_COLOR_RESET   "\x1B[0m"
+
+/* ===== CONSTANTS DEFINITION ===== */
+
+// Constant strings that store the command line options available.
+extern const char *ARGUMENT_TIME;
+extern const char *ARGUMENT_DELTA;
+extern const char *ARGUMENT_OUTPUT_FILENAME;
+// Default filename used for the output.
+extern char *DEFAULT_OUTPUT_FILENAME;
+
+/* ===== STRUCTURES ===== */
+
+// Structures used in gettimeofday
+extern struct timeval startwtime, endwtime;
+
+// A data structure to conveniently hold the algorithm's parameters.
+typedef struct parameters {
+	double time, delta;
+	char *outputFilename;
+	int numberOfSamples;
+} Parameters;
+
+/* ===== FUNCTION DEFINITIONS ===== */
+
+// Function that implements the sampling experiment.
+void testSampling(double ***samplesMatrix, Parameters parameters);
+
+void handle_alarm(int sig);
+
+// Function validUsage outputs the correct way to use the program with command line arguments.
+void validUsage(char *programName);
+
+// Function checkIncrement is a helper function used in parseArguments (see bellow).
+int checkIncrement(int previousIndex, int maxIndex, char *programName);
+
+// Function parseArguments parses command line arguments.
+void parseArguments(int argumentCount, char **argumentVector, Parameters *parameters);
+
+// Function saveSamplesToFile appends the sample matrix "samplesMatrix" to the file with the
+// filename supplied in the arguments.
+void saveSamplesToFile(char *filename, double **samplesMatrix, int matrixRows);
+
+#endif	// TEST_SAMPLE_FUNCTIONS_H