Improve logging

Also keep track of whether the user got right or wrong. Optimize the
allocation and modification of the log character buffer.

1 files changed, 42 insertions, 19 deletions

diff --git a/src/calculer.c b/src/calculer.c
index 2d6c973..062fff6 100644
--- a/src/calculer.c
+++ b/src/calculer.c
@@ -30,6 +30,8 @@ static int lower = 0;
 static int upper = 100;
 
 static FILE *logfile;
+static char logbuf[64];
+#define LOGBUF_OFFSET 11
 
 /* Return a random number x such that lower <= x < upper. */
 static int
@@ -38,47 +40,60 @@ calculer_rand(void)
 	return lower + rand()%(upper-lower);
 }
 
+static intptr_t
+tp_ms(struct timespec const *tp)
+{
+	return tp->tv_sec*1000 + tp->tv_nsec/1000000;
+}
+
 static void *
 measure_before(void)
 {
-	/* TODO: measure time in ms */
-	return (void *) time(NULL);
+	struct timespec tp;
+	clock_gettime(CLOCK_REALTIME, &tp);
+	return (void *)tp_ms(&tp);
 }
 
 int
-measure_after(void *data)
+measure_after(void *data, int correct)
 {
 	int t0 = (intptr_t) data;
-	time_t now = time(NULL);
-	int dt = now - t0;
-	char buf[64] = {0};
-	struct tm *tm = localtime(&now);
-	size_t bytes_written = strftime(buf, sizeof(buf), "%F\t", tm);
-	assert(bytes_written);
-	bytes_written += sprintf(buf + bytes_written, "%d\n", dt);
-
-	return bytes_written != fwrite(buf, 1, bytes_written, logfile);
+	struct timespec tp;
+	clock_gettime(CLOCK_REALTIME, &tp);
+	int t1 = tp_ms(&tp);
+	int dt = t1 - t0;
+	size_t bytes_written =
+		LOGBUF_OFFSET + sprintf(logbuf + LOGBUF_OFFSET,
+					"%d\t%d\n", dt, correct);
+
+	return bytes_written != fwrite(logbuf, 1, bytes_written, logfile);
 }
 
 int
 main(void)
 {
-	char prompt[31] = {0};
-	int x, y, res;
-	char *input;
-
 	srand(time(NULL));
 	logfile = fopen("./calculer.log", "a");
 	assert(logfile);
 
+	time_t now = time(NULL);
+	struct tm *tm = localtime(&now);
+	size_t bytes_written = strftime(logbuf, sizeof(logbuf), "%F\t", tm);
+	assert(bytes_written);
+
 	while (1)
 	{
+		char prompt[32] = {0};
+		int x, y, res;
+		char *input;
+		int input_val;
+
 		x = calculer_rand();
 		y = calculer_rand();
-		void *measure_data = measure_before();
 		res = x+y;
-		assert(!measure_after(measure_data));
+
 		sprintf(prompt, "%d + %d = ", x, y);
+		void *measure_data = measure_before();
 		input = linenoise(prompt);
 
 		if ((!input) || (*input == '\0'))
@@ -88,7 +103,15 @@ main(void)
 			exit(0);
 		}
 
-		if (atoi(input) == res)
+		input_val = atoi(input);
+		if (measure_after(measure_data, input_val == res))
+		{
+			free(input);
+			fclose(logfile);
+			exit(1);
+		}
+
+		if (input_val == res)
 			printf("RIGHT\n");
 		else
 			printf("WRONG\n");