X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftally%2Ftally.c;h=0d0190795557b60ccfe8d73138dfda2baf99477d;hp=9f2a4591f8c3ce5ddd05b8f29702ff2761784dad;hb=97648992fdd50535fe276261368c179df993202b;hpb=fdea8abee49e9158275741c210bbb27caf6754fa

diff --git a/ccan/tally/tally.c b/ccan/tally/tally.c
index 9f2a4591..0d019079 100644
--- a/ccan/tally/tally.c
+++ b/ccan/tally/tally.c
@@ -16,25 +16,28 @@ struct tally {
 	size_t total[2];
 	/* This allows limited frequency analysis. */
 	unsigned buckets, step_bits;
-	size_t counts[1 /* [buckets] */ ];
+	size_t counts[1 /* Actually: [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) {
 		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;
 }
@@ -319,7 +322,7 @@ ssize_t tally_total(const struct tally *tally, ssize_t *overflow)
 	}
 
 	/* If result is negative, make sure we can represent it. */
-	if (tally->total[1] & (1 << (SIZET_BITS-1))) {
+	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
@@ -422,7 +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;
@@ -452,14 +455,17 @@ char *tally_histogram(const struct tally *tally,
 	}
 
 	for (i = 0; i < height; i++) {
-		unsigned covered = 1;
-		count = (double)tally->counts[i] / largest_bucket * (width-1)+1;
+		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);
-		else if (i == bucket_of(tally->min, tally->step_bits, 0))
+		else if (row == bucket_of(tally->min, tally->step_bits, 0))
 			*p = '+';
 		else
 			*p = '|';