--- joko/Uni/BSArch/01/prime.c	2006/05/12 18:41:34	1.1
+++ joko/Uni/BSArch/01/prime.c	2006/05/15 11:25:40	1.15
@@ -1,32 +1,156 @@
+/* $Id: prime.c,v 1.15 2006/05/15 11:25:40 franky Exp $ */
+
 #include <stdio.h>
+#include <stdlib.h>
 #include <math.h>
-#define PRINTPRIME(x) if(prime(x)) printf("%i\n", x)
-int prime(int number)
+#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
+
+
+/* check for prime number */
+BOOL is_prime(long int number)
 {
-  int i;
-  for(i=2;i*i<=number;i++){
-  	if((number%i) == 0)
-	  return 0;
-  }
-  return 1;
+	int i,sq;
+	/* negative values, 0 and 1 are never prime numbers */
+	if (number < 2) return FALSE;
+	sq=sqrt(number);
+	
+	/* check all numbers 2..sqrt(number) for being a prime number */
+	for (i=2; i <= sq; i++) {
+		if ((number % i) == 0)
+			return FALSE;
+	}
+	return TRUE;
 }
+
+/* convert from string to long int, with error checking */
+long int convert_number(const char *nptr, BOOL warn) {
+	
+	char * endptr;
+	errno = 0;
+	long int number;
+
+	number = strtol(nptr, &endptr, 10);
+	
+	/* invalid characters? */
+	if (*endptr != '\0') {
+		char message[256];
+		snprintf(message, 255, "Could not convert '%s' to a valid (integer) number.", nptr);
+		if(warn) 
+			PRINTWARNING(message);
+		else{
+			PRINTERROR(message);
+		 	exit(EXIT_FAILURE);
+		}
+	}
+	
+	/* invalid range? */
+	/* if (number == LONG_MAX || number == LONG_MIN) { */
+	if (errno == ERANGE) {
+		char message[256];
+		snprintf(message, 255, "Number is not in range of 'long int': %s", nptr);
+		if(warn)
+			PRINTWARNING(message);
+		else{			
+			PRINTERROR(message);
+			exit(EXIT_FAILURE);
+		}
+	}
+	
+	return number;
+	
+}
+
 int main(int argc, char * argv[])
 {
-	int i, j;
-	FILE * fp;
-	char num[11];
-	if(argc > 2 ){
-		j=atoi(argv[2]);
-		for(i=atoi(argv[1]) ; i< j; i++){
+	
+	if (argc == 1) {
+		PRINTERROR("No arguments given.");
+		exit(EXIT_FAILURE);
+	}
+	
+	/* (3) range mode */
+	if (argc > 2) {
+		long int i, j;
+		i = convert_number(argv[1],FALSE);
+		j = convert_number(argv[2],FALSE);
+		for (i; i< j; i++) {
 			PRINTPRIME(i);
 		}
-	}else {
-		fp=fopen(argv[1], "r");
-		if(fp==NULL){
-			PRINTPRIME(atoi(argv[1]));
-		}else{
-			while(fgets(num, 11, fp))
-				PRINTPRIME(atoi(num));
+	
+	/* other modes */
+	} else {
+		int err;
+		/* try to open file for reading */
+		FILE * fp = fopen(argv[1], "r");
+		err=errno;
+		/* (1) test-single-number mode: first argument is not a filename */
+		if (fp == NULL) {
+			long int number = convert_number(argv[1],TRUE);
+			if(err){
+				fprintf(stderr, "%s: %s\n", argv[1], strerror(err));
+				return -1;
+			}
+			PRINTPRIME(number);
+		
+		/* (2) file mode: read numbers from file */
+		} else {
+			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,FALSE);
+				PRINTPRIME(number);
+				
+			}
 			fclose(fp);
 		}
 	}