X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftally%2Ftally.c;h=0d0190795557b60ccfe8d73138dfda2baf99477d;hp=1433a3aa2650e45cf2bfc44c3bce646400f8dfba;hb=97648992fdd50535fe276261368c179df993202b;hpb=7a36f69eea4ee572bdf191d6048350751cd2ab5b

diff --git a/ccan/tally/tally.c b/ccan/tally/tally.c
index 1433a3aa..0d019079 100644
--- a/ccan/tally/tally.c
+++ b/ccan/tally/tally.c
@@ -8,46 +8,36 @@
 #include <stdio.h>
 #include <assert.h>
 
-#define MAX_STEP_BITS (sizeof(size_t)*CHAR_BIT)
+#define SIZET_BITS (sizeof(size_t)*CHAR_BIT)
 
 /* We use power of 2 steps.  I tried being tricky, but it got buggy. */
 struct tally {
 	ssize_t min, max;
 	size_t total[2];
 	/* This allows limited frequency analysis. */
-	size_t buckets;
-	size_t step_bits;
-	size_t counts[1 /* [buckets] */ ];
+	unsigned buckets, step_bits;
+	size_t counts[1 /* Actually: [buckets] */ ];
 };
 
-struct tally *tally_new(size_t buckets)
+struct tally *tally_new(unsigned buckets)
 {
 	struct tally *tally;
 
+	/* There is always 1 bucket. */
+	if (buckets == 0)
+		buckets = 1;
+
 	/* Check for overflow. */
 	if (buckets && SIZE_MAX / buckets < sizeof(tally->counts[0]))
 		return NULL;
-	tally = malloc(sizeof(*tally) + sizeof(tally->counts[0])*buckets);
+	tally = malloc(sizeof(*tally) + sizeof(tally->counts[0])*(buckets-1));
 	if (tally) {
-		/* SSIZE_MAX isn't portable, so make it one of these types. */
-		BUILD_ASSERT(sizeof(tally->min) == sizeof(int)
-			     || sizeof(tally->min) == sizeof(long)
-			     || sizeof(tally->min) == sizeof(long long));
-		if (sizeof(tally->min) == sizeof(int)) {
-			tally->min = INT_MAX;
-			tally->max = INT_MIN;
-		} else if (sizeof(tally->min) == sizeof(long)) {
-			tally->min = LONG_MAX;
-			tally->max = LONG_MIN;
-		} else if (sizeof(tally->min) == sizeof(long long)) {
-			tally->min = (ssize_t)LLONG_MAX;
-			tally->max = (ssize_t)LLONG_MIN;
-		}
+		tally->max = ((size_t)1 << (SIZET_BITS - 1));
+		tally->min = ~tally->max;
 		tally->total[0] = tally->total[1] = 0;
-		/* There is always 1 bucket. */
-		tally->buckets = buckets+1;
+		tally->buckets = buckets;
 		tally->step_bits = 0;
-		memset(tally->counts, 0, sizeof(tally->counts[0])*(buckets+1));
+		memset(tally->counts, 0, sizeof(tally->counts[0])*buckets);
 	}
 	return tally;
 }
@@ -55,9 +45,9 @@ struct tally *tally_new(size_t buckets)
 static unsigned bucket_of(ssize_t min, unsigned step_bits, ssize_t val)
 {
 	/* Don't over-shift. */
-	if (step_bits == MAX_STEP_BITS)
+	if (step_bits == SIZET_BITS)
 		return 0;
-	assert(step_bits < MAX_STEP_BITS);
+	assert(step_bits < SIZET_BITS);
 	return (size_t)(val - min) >> step_bits;
 }
 
@@ -65,9 +55,9 @@ static unsigned bucket_of(ssize_t min, unsigned step_bits, ssize_t val)
 static ssize_t bucket_min(ssize_t min, unsigned step_bits, unsigned b)
 {
 	/* Don't over-shift. */
-	if (step_bits == MAX_STEP_BITS)
+	if (step_bits == SIZET_BITS)
 		return min;
-	assert(step_bits < MAX_STEP_BITS);
+	assert(step_bits < SIZET_BITS);
 	return min + ((ssize_t)b << step_bits);
 }
 
@@ -324,6 +314,33 @@ ssize_t tally_mean(const struct tally *tally)
 	return divls64(tally->total[1], tally->total[0], count);
 }
 
+ssize_t tally_total(const struct tally *tally, ssize_t *overflow)
+{
+	if (overflow) {
+		*overflow = tally->total[1];
+		return tally->total[0];
+	}
+
+	/* If result is negative, make sure we can represent it. */
+	if (tally->total[1] & ((size_t)1 << (SIZET_BITS-1))) {
+		/* Must have only underflowed once, and must be able to
+		 * represent result at ssize_t. */
+		if ((~tally->total[1])+1 != 0
+		    || (ssize_t)tally->total[0] >= 0) {
+			/* Underflow, return minimum. */
+			return (ssize_t)((size_t)1 << (SIZET_BITS - 1));
+		}
+	} else {
+		/* Result is positive, must not have overflowed, and must be
+		 * able to represent as ssize_t. */
+		if (tally->total[1] || (ssize_t)tally->total[0] < 0) {
+			/* Overflow.  Return maximum. */
+			return (ssize_t)~((size_t)1 << (SIZET_BITS - 1));
+		}
+	}
+	return tally->total[0];
+}
+
 static ssize_t bucket_range(const struct tally *tally, unsigned b, size_t *err)
 {
 	ssize_t min, max;
@@ -408,7 +425,7 @@ char *tally_histogram(const struct tally *tally,
 	} else {
 		/* We create a temporary then renormalize so < height. */
 		/* FIXME: Antialias properly! */
-		tmp = tally_new(tally->buckets-1);
+		tmp = tally_new(tally->buckets);
 		if (!tmp)
 			return NULL;
 		tmp->min = tally->min;
@@ -417,7 +434,7 @@ char *tally_histogram(const struct tally *tally,
 		memcpy(tmp->counts, tally->counts,
 		       sizeof(tally->counts[0]) * tmp->buckets);
 		while ((max_bucket = get_max_bucket(tmp)) >= height)
-			renormalize(tmp, tmp->min, tmp->max *= 2);
+			renormalize(tmp, tmp->min, tmp->max * 2);
 		/* Restore max */
 		tmp->max = tally->max;
 		tally = tmp;
@@ -436,23 +453,32 @@ char *tally_histogram(const struct tally *tally,
 		free(tmp);
 		return NULL;
 	}
+
 	for (i = 0; i < height; i++) {
-		unsigned covered = 0;
-		count = (double)tally->counts[i] / largest_bucket * width;
+		unsigned covered = 1, row;
+
+		/* People expect minimum at the bottom. */
+		row = height - i - 1;
+		count = (double)tally->counts[row] / largest_bucket * (width-1)+1;
 
-		if (i == 0)
+		if (row == 0)
 			covered = snprintf(p, width, "%zi", tally->min);
-		else if (i == height - 1)
+		else if (row == height - 1)
 			covered = snprintf(p, width, "%zi", tally->max);
-		if (covered) {
-			if (covered > width)
-				covered = width;
-			p += covered;
-			if (count > covered)
-				count -= covered;
-			else
-				count = 0;
-		}
+		else if (row == bucket_of(tally->min, tally->step_bits, 0))
+			*p = '+';
+		else
+			*p = '|';
+
+		if (covered > width)
+			covered = width;
+		p += covered;
+
+		if (count > covered)
+			count -= covered;
+		else
+			count = 0;
+
 		memset(p, '*', count);
 		p += count;
 		*p = '\n';