hash: use config.h settings for endian.
[ccan] / ccan / tally / tally.c
index 9f2a4591f8c3ce5ddd05b8f29702ff2761784dad..0d0190795557b60ccfe8d73138dfda2baf99477d 100644 (file)
@@ -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 = '|';