--- joko/Uni/BSArch/01/prime.c	2006/05/12 19:53:48	1.4
+++ joko/Uni/BSArch/01/prime.c	2006/05/13 18:53:54	1.13
@@ -1,51 +1,142 @@
+/* $Id: prime.c,v 1.13 2006/05/13 18:53:54 joko Exp $ */
+
 #include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <errno.h>
+
+#ifdef _MSC_VER
+#define snprintf _snprintf
+#endif
+
+#define BOOL int
+#define TRUE 1
+#define FALSE 0
+
+#define PRINTPRIME(x) if (is_prime(x)) printf("%i\n", x)
+#define PRINTERROR(message) fprintf(stderr, "ERROR: %s\n", message)
+#define PRINTWARNING(message) fprintf(stderr, "WARNING: %s\n", message)
+
+#define MAX_LINE_LENGTH 80
 
-#define PRINTPRIME(x) if(is_prime(x)) printf("%i\n", x)
-#define PRINTERROR(message) printf("ERROR: %s\n", message)
 
-// check for prime number
-int is_prime(int number)
+/* check for prime number */
+BOOL is_prime(long int number)
 {
 	int i;
+	
+	/* negative values, 0 and 1 are never prime numbers */
+	if (number < 2) return FALSE;
+	
+	/* check all numbers 2..sqrt(number) for being a prime number */
 	for (i=2; i*i <= number; i++) {
 		if ((number % i) == 0)
-			return 0;
+			return FALSE;
 	}
-	return 1;
+	return TRUE;
+}
+
+/* convert from string to long int, with error checking */
+long int convert_number(const char *nptr) {
+	
+	char * endptr;
+	long int number = strtol(nptr, &endptr, 10);
+
+	errno = 0;
+	
+	/* invalid characters? */
+	if (*endptr != '\0') {
+		char message[254];
+		snprintf(message, 256, "Could not convert '%s' to a valid (integer) number.", nptr);
+		PRINTERROR(message);
+		exit(EXIT_FAILURE);
+	}
+	
+	/* invalid range? */
+	/* if (number == LONG_MAX || number == LONG_MIN) { */
+	if (errno == ERANGE) {
+		char message[254];
+		snprintf(message, 256, "Number is not in range of 'long int': %s", nptr);
+		PRINTERROR(message);
+		exit(EXIT_FAILURE);
+	}
+	
+	return number;
+	
 }
 
 int main(int argc, char * argv[])
 {
 	
-	// TODO: segfaults if zero arguments given
-	// switch/case???
 	if (argc == 1) {
-		PRINTERROR("No arguments given, will segfault under cygwin. :-)");
+		PRINTERROR("No arguments given.");
+		exit(EXIT_FAILURE);
 	}
 	
-	// (3) range mode
+	/* (3) range mode */
 	if (argc > 2) {
-		int i, j;
-		j = atoi(argv[2]);
-		for (i = atoi(argv[1]); i< j; i++) {
+		long int i, j;
+		i = convert_number(argv[1]);
+		j = convert_number(argv[2]);
+		for (i; i< j; i++) {
 			PRINTPRIME(i);
 		}
 	
-	// other modes
+	/* other modes */
 	} else {
 
-		// try to open file for reading
+		/* try to open file for reading */
 		FILE * fp = fopen(argv[1], "r");
 		
-		// (1) test-single-number mode: first argument is not a filename
+		/* (1) test-single-number mode: first argument is not a filename */
 		if (fp == NULL) {
-			PRINTPRIME(atoi(argv[1]));
+			long int number = convert_number(argv[1]);
+			PRINTPRIME(number);
 		
-		// (2) file mode: read numbers from file
+		/* (2) file mode: read numbers from file */
 		} else {
-			char num[11];
-			while (fgets(num, 11, fp))
-				PRINTPRIME(atoi(num));
+			char line[MAX_LINE_LENGTH + 1];
+			long int number;
+			int line_length;
+			long int line_no = 0;
+			while (fgets(line, MAX_LINE_LENGTH + 1, fp)) {
+				
+				/* count line number (for warnings) */
+				line_no++;
+
+				line_length = strlen(line);
+				
+				/* skip empty lines */
+				if (strlen(line) < 2) continue;
+
+				/* line handling: policy = skip exceeding lines */
+				
+				/* line exceeds max length */
+				if (line_length == MAX_LINE_LENGTH && line[line_length-1] != '\n') {
+					char message[254];
+					snprintf(message, 256, "Line too long (max %i chars) in line number: %i", MAX_LINE_LENGTH, line_no);
+					PRINTWARNING(message);
+					
+					/* eat all characters until newline or EOF */
+					while (1) {
+						int charcode = fgetc(fp);
+						if (charcode == 10 || charcode == EOF) break;
+					}
+					
+					/* skip this line from prime calculation */
+					continue;
+				}
+				
+				/* if last char is newline, strip it */
+				if (line[line_length-1] == '\n') {
+					line[line_length-1] = '\0';
+				}
+				
+				/* finally: prime number calculation and output */
+				number = convert_number(line);
+				PRINTPRIME(number);
+				
+			}
 			fclose(fp);
 		}
 	}