Multiple mostly-stylistic changes, and improved argument checking.

parse_int_arg no checks that -E is given nothing larger than a long.
Simplified conditions in increment_result_counters.
Added braces to conditional blocks without any.
Added conditions to stop if calloc returns NULL.

csim.c

@@ -11,9 +11,10 @@
    With the verbose option (-v), outputs details for each operation.
 
    Exit statuses:
-   0 - success
+    0 - success
-   1 - usage error
+    1 - usage error
    -1 - file error
+    2 - memory error
 */
 
 /**** Headers ****/
@@ -126,16 +127,16 @@ int main(int argc, char* argv[])
 
 	/* FILE READING */
 	FILE* f = fopen(filename, "r");
-	if(!f)
+	if(!f) {
-	{
 		printf("Invalid file name: %s", filename);
 		exit(-1);
 	}
 
 	//char buffer[20];
 	while (fgets(buffer, 20, f)) {
-		if (buffer[0] == 'I')
+		if (buffer[0] == 'I') {
 			continue;
+		}
 
 		char* end;
 		char op = buffer[1];
@@ -257,12 +258,19 @@ long bits_to_size(int bits)
  */
 void increment_result_counters(char result, results* score)
 {
-	score->hits += (result == 'H');
+	if (result == 'H') {
-	score->misses += (result == 'M' || result == 'E');
+		score->hits++;
-	score->evictions += (result == 'E');
+		mprintf(" hit");
-	if (result == 'H') mprintf(" hit");
+	}
-	if (result == 'M') mprintf(" miss");
+	else if (result == 'M') {
-	if (result == 'E') mprintf(" miss eviction");
+		score->misses++;
+		mprintf(" miss");
+	}
+	else if (result == 'E') {
+		score->misses++;
+		score->evictions++;
+		mprintf(" miss eviction");
+	}
 }
 
 
@@ -278,6 +286,10 @@ void increment_result_counters(char result, results* score)
 linked_line** make_cache(long num_sets, long num_lines)
 {
 	linked_line** cache = (linked_line**)calloc(num_sets, sizeof(linked_line*));
+	if (! cache) {
+		printf("Error: calloc failed\n");
+		exit(2);
+	}
 	long ii;
 	for (ii = 0; ii < num_sets; ii++) {
 		cache[ii] = make_set(NULL, num_lines);
@@ -290,9 +302,15 @@ linked_line** make_cache(long num_sets, long num_lines)
    @param newer A pointer to the previously-created element of the set.
    @param num_lines The number of lines remaining to be added.
    @return A pointer to the created line.
+   @bug Large values for num_lines result in a segfault in the call to calloc.
+   @TODO Free already-allocated space in event of allocation failure.
 */
 linked_line* make_set(linked_line* newer, long num_lines) {
 	linked_line* current = (linked_line*)calloc(1, sizeof(linked_line));
+	if (! current) {
+		printf("Error: calloc failed\n");
+		exit(2);
+	}
 	current->newer = newer;
 	num_lines--;
 	if (num_lines) { // If not on the last line
@@ -384,14 +402,21 @@ char cache_access(linked_line** cache, long address,
 	linked_line* set_head = cache[set];
 	linked_line* line = find_line(set_head, tag);
 
-	if (!line->validity)       out = 'M';
+	if (!line->validity) {
-	else if (line->tag == tag) out = 'H';
+		out = 'M';
-	else                       out = 'E';
+	}
+	else if (line->tag == tag) {
+		out = 'H';
+	}
+	else {
+		out = 'E';
+	}
 
 	if(!(line == set_head)) {
 		line->newer->older = line->older;
-		if(line->older)
+		if(line->older) {
 			line->older->newer = line->newer;
+		}
 		line->newer = NULL;
 		line->older = set_head;
 		set_head->newer = line;
@@ -415,10 +440,12 @@ char cache_access(linked_line** cache, long address,
  */
 linked_line* find_line(linked_line* line, long tag)
 {
-	if(line->tag == tag || !line->validity || !line->older)
+	if (line->tag == tag || !line->validity || !line->older) {
 		return line;
-	else
+	}
+	else {
 		return find_line(line->older, tag);
+	}
 }