1 files changed, 106 insertions, 0 deletions
diff --git a/malloclab-handout/ftimer.c b/malloclab-handout/ftimer.c
new file mode 100644
index 0000000..ea08560
--- /dev/null
+++ b/malloclab-handout/ftimer.c
@@ -0,0 +1,106 @@
+/*
+ * ftimer.c - Estimate the time (in seconds) used by a function f 
+ * 
+ * Copyright (c) 2002, R. Bryant and D. O'Hallaron, All rights reserved.
+ * May not be used, modified, or copied without permission.
+ *
+ * Function timers that estimate the running time (in seconds) of a function f.
+ *    ftimer_itimer: version that uses the interval timer
+ *    ftimer_gettod: version that uses gettimeofday
+ */
+#include <stdio.h>
+#include <sys/time.h>
+#include "ftimer.h"
+
+/* function prototypes */
+static void init_etime(void);
+static double get_etime(void);
+
+/* 
+ * ftimer_itimer - Use the interval timer to estimate the running time
+ * of f(argp). Return the average of n runs.  
+ */
+double ftimer_itimer(ftimer_test_funct f, void *argp, int n)
+{
+    double start, tmeas;
+    int i;
+
+    init_etime();
+    start = get_etime();
+    for (i = 0; i < n; i++) 
+	f(argp);
+    tmeas = get_etime() - start;
+    return tmeas / n;
+}
+
+/* 
+ * ftimer_gettod - Use gettimeofday to estimate the running time of
+ * f(argp). Return the average of n runs.  
+ */
+double ftimer_gettod(ftimer_test_funct f, void *argp, int n)
+{
+    int i;
+    struct timeval stv, etv;
+    double diff;
+
+    gettimeofday(&stv, NULL);
+    for (i = 0; i < n; i++) 
+	f(argp);
+    gettimeofday(&etv,NULL);
+    diff = 1E3*(etv.tv_sec - stv.tv_sec) + 1E-3*(etv.tv_usec-stv.tv_usec);
+    diff /= n;
+    return (1E-3*diff);
+}
+
+
+/*
+ * Routines for manipulating the Unix interval timer
+ */
+
+/* The initial value of the interval timer */
+#define MAX_ETIME 86400   
+
+/* static variables that hold the initial value of the interval timer */
+static struct itimerval first_u; /* user time */
+static struct itimerval first_r; /* real time */
+static struct itimerval first_p; /* prof time*/
+
+/* init the timer */
+static void init_etime(void)
+{
+    first_u.it_interval.tv_sec = 0;
+    first_u.it_interval.tv_usec = 0;
+    first_u.it_value.tv_sec = MAX_ETIME;
+    first_u.it_value.tv_usec = 0;
+    setitimer(ITIMER_VIRTUAL, &first_u, NULL);
+
+    first_r.it_interval.tv_sec = 0;
+    first_r.it_interval.tv_usec = 0;
+    first_r.it_value.tv_sec = MAX_ETIME;
+    first_r.it_value.tv_usec = 0;
+    setitimer(ITIMER_REAL, &first_r, NULL);
+   
+    first_p.it_interval.tv_sec = 0;
+    first_p.it_interval.tv_usec = 0;
+    first_p.it_value.tv_sec = MAX_ETIME;
+    first_p.it_value.tv_usec = 0;
+    setitimer(ITIMER_PROF, &first_p, NULL);
+}
+
+/* return elapsed real seconds since call to init_etime */
+static double get_etime(void) {
+    struct itimerval v_curr;
+    struct itimerval r_curr;
+    struct itimerval p_curr;
+
+    getitimer(ITIMER_VIRTUAL, &v_curr);
+    getitimer(ITIMER_REAL,&r_curr);
+    getitimer(ITIMER_PROF,&p_curr);
+
+    return (double) ((first_p.it_value.tv_sec - r_curr.it_value.tv_sec) +
+		     (first_p.it_value.tv_usec - r_curr.it_value.tv_usec)*1e-6);
+}
+
+
+
+