tally: simplify, add Y axis to graph.

[ccan] / ccan / tally / tally.c

diff --git a/ccan/tally/tally.c b/ccan/tally/tally.c
index 88407cf985ccfb30996383b51e7c291af00319fe..9f2a4591f8c3ce5ddd05b8f29702ff2761784dad 100644 (file)
--- a/ccan/tally/tally.c
+++ b/ccan/tally/tally.c
@@ -15,12 +15,11 @@ struct tally {
        ssize_t min, max;
        size_t total[2];
        /* This allows limited frequency analysis. */
-       size_t buckets;
-       size_t step_bits;
+       unsigned buckets, step_bits;
        size_t counts[1 /* [buckets] */ ];
 };
 
-struct tally *tally_new(size_t buckets)
+struct tally *tally_new(unsigned buckets)
 {
        struct tally *tally;
 
@@ -29,20 +28,8 @@ struct tally *tally_new(size_t buckets)
                return NULL;
        tally = malloc(sizeof(*tally) + sizeof(tally->counts[0])*buckets);
        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;
@@ -444,7 +431,7 @@ 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;
@@ -463,23 +450,29 @@ 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;
+               count = (double)tally->counts[i] / largest_bucket * (width-1)+1;
 
                if (i == 0)
                        covered = snprintf(p, width, "%zi", tally->min);
                else if (i == 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 (i == 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';