struct tally *tally;
/* There is always 1 bucket. */
- if (buckets == 0)
+ if (buckets == 0) {
buckets = 1;
+ }
/* Overly cautious check for overflow. */
- if (sizeof(*tally) * buckets / sizeof(*tally) != buckets)
+ if (sizeof(*tally) * buckets / sizeof(*tally) != buckets) {
return NULL;
+ }
+
tally = (struct 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;
- tally->buckets = buckets;
- tally->step_bits = 0;
- memset(tally->counts, 0, sizeof(tally->counts[0])*buckets);
+ if (tally == NULL) {
+ return NULL;
}
+
+ tally->max = ((size_t)1 << (SIZET_BITS - 1));
+ tally->min = ~tally->max;
+ tally->total[0] = tally->total[1] = 0;
+ tally->buckets = buckets;
+ tally->step_bits = 0;
+ memset(tally->counts, 0, sizeof(tally->counts[0])*buckets);
return tally;
}
static unsigned bucket_of(ssize_t min, unsigned step_bits, ssize_t val)
{
/* Don't over-shift. */
- if (step_bits == SIZET_BITS)
+ if (step_bits == SIZET_BITS) {
return 0;
+ }
assert(step_bits < SIZET_BITS);
return (size_t)(val - min) >> step_bits;
}
static ssize_t bucket_min(ssize_t min, unsigned step_bits, unsigned b)
{
/* Don't over-shift. */
- if (step_bits == SIZET_BITS)
+ if (step_bits == SIZET_BITS) {
return min;
+ }
assert(step_bits < SIZET_BITS);
return min + ((ssize_t)b << step_bits);
}
/* Does shifting by this many bits truncate the number? */
static bool shift_overflows(size_t num, unsigned bits)
{
- if (bits == 0)
+ if (bits == 0) {
return false;
+ }
return ((num << bits) >> 1) != (num << (bits - 1));
}
unsigned int i, old_min;
/* Uninitialized? Don't do anything... */
- if (tally->max < tally->min)
+ if (tally->max < tally->min) {
goto update;
+ }
/* If we don't have sufficient range, increase step bits until
* buckets cover entire range of ssize_t anyway. */
new_max = val;
need_renormalize = true;
}
- if (need_renormalize)
+ if (need_renormalize) {
renormalize(tally, new_min, new_max);
+ }
/* 128-bit arithmetic! If we didn't want exact mean, we could just
* pull it out of counts. */
- if (val > 0 && tally->total[0] + val < tally->total[0])
+ if (val > 0 && tally->total[0] + val < tally->total[0]) {
tally->total[1]++;
- else if (val < 0 && tally->total[0] + val > tally->total[0])
+ } else if (val < 0 && tally->total[0] + val > tally->total[0]) {
tally->total[1]--;
+ }
tally->total[0] += val;
tally->counts[bucket_of(tally->min, tally->step_bits, val)]++;
}
size_t tally_num(const struct tally *tally)
{
size_t i, num = 0;
- for (i = 0; i < tally->buckets; i++)
+ for (i = 0; i < tally->buckets; i++) {
num += tally->counts[i];
+ }
return num;
}
#endif
uint64_t r = 64;
- if (!val)
+ if (!val) {
return 0;
+ }
if (!(val & 0xffffffff00000000ull)) {
val <<= 32;
r -= 32;
/* This is stolen straight from Hacker's Delight. */
static uint64_t divlu64(uint64_t u1, uint64_t u0, uint64_t v)
{
- const uint64_t b = 4294967296ULL; // Number base (32 bits).
- uint32_t un[4], // Dividend and divisor
- vn[2]; // normalized and broken
- // up into halfwords.
- uint32_t q[2]; // Quotient as halfwords.
- uint64_t un1, un0, // Dividend and divisor
- vn0; // as fullwords.
- uint64_t qhat; // Estimated quotient digit.
- uint64_t rhat; // A remainder.
- uint64_t p; // Product of two digits.
+ const uint64_t b = 4294967296ULL; /* Number base (32 bits). */
+ uint32_t un[4], /* Dividend and divisor */
+ vn[2]; /* normalized and broken */
+ /* up into halfwords. */
+ uint32_t q[2]; /* Quotient as halfwords. */
+ uint64_t un1, un0, /* Dividend and divisor */
+ vn0; /* as fullwords. */
+ uint64_t qhat; /* Estimated quotient digit. */
+ uint64_t rhat; /* A remainder. */
+ uint64_t p; /* Product of two digits. */
int64_t s, i, j, t, k;
- if (u1 >= v) // If overflow, return the largest
- return (uint64_t)-1; // possible quotient.
+ if (u1 >= v) { /* If overflow, return the largest */
+ return (uint64_t)-1; /* possible quotient. */
+ }
- s = 64 - fls64(v); // 0 <= s <= 63.
- vn0 = v << s; // Normalize divisor.
- vn[1] = vn0 >> 32; // Break divisor up into
- vn[0] = vn0 & 0xFFFFFFFF; // two 32-bit halves.
+ s = 64 - fls64(v); /* 0 <= s <= 63. */
+ vn0 = v << s; /* Normalize divisor. */
+ vn[1] = vn0 >> 32; /* Break divisor up into */
+ vn[0] = vn0 & 0xFFFFFFFF; /* two 32-bit halves. */
// Shift dividend left.
un1 = ((u1 << s) | (u0 >> (64 - s))) & (-s >> 63);
un0 = u0 << s;
- un[3] = un1 >> 32; // Break dividend up into
- un[2] = un1; // four 32-bit halfwords
- un[1] = un0 >> 32; // Note: storing into
- un[0] = un0; // halfwords truncates.
+ un[3] = un1 >> 32; /* Break dividend up into */
+ un[2] = un1; /* four 32-bit halfwords */
+ un[1] = un0 >> 32; /* Note: storing into */
+ un[0] = un0; /* halfwords truncates. */
for (j = 1; j >= 0; j--) {
- // Compute estimate qhat of q[j].
+ /* Compute estimate qhat of q[j]. */
qhat = (un[j+2]*b + un[j+1])/vn[1];
rhat = (un[j+2]*b + un[j+1]) - qhat*vn[1];
again:
if (qhat >= b || qhat*vn[0] > b*rhat + un[j]) {
qhat = qhat - 1;
rhat = rhat + vn[1];
- if (rhat < b) goto again;
+ if (rhat < b) {
+ goto again;
+ }
}
- // Multiply and subtract.
+ /* Multiply and subtract. */
k = 0;
for (i = 0; i < 2; i++) {
p = qhat*vn[i];
t = un[j+2] - k;
un[j+2] = t;
- q[j] = qhat; // Store quotient digit.
- if (t < 0) { // If we subtracted too
- q[j] = q[j] - 1; // much, add back.
+ q[j] = qhat; /* Store quotient digit. */
+ if (t < 0) { /* If we subtracted too */
+ q[j] = q[j] - 1; /* much, add back. */
k = 0;
for (i = 0; i < 2; i++) {
t = un[i+j] + vn[i] + k;
}
un[j+2] = un[j+2] + k;
}
- } // End j.
+ } /* End j. */
return q[1]*b + q[0];
}
{
int64_t q, uneg, vneg, diff, borrow;
- uneg = u1 >> 63; // -1 if u < 0.
- if (uneg) { // Compute the absolute
- u0 = -u0; // value of the dividend u.
+ uneg = u1 >> 63; /* -1 if u < 0. */
+ if (uneg) { /* Compute the absolute */
+ u0 = -u0; /* value of the dividend u. */
borrow = (u0 != 0);
u1 = -u1 - borrow;
}
- vneg = v >> 63; // -1 if v < 0.
- v = (v ^ vneg) - vneg; // Absolute value of v.
+ vneg = v >> 63; /* -1 if v < 0. */
+ v = (v ^ vneg) - vneg; /* Absolute value of v. */
- if ((uint64_t)u1 >= (uint64_t)v)
+ if ((uint64_t)u1 >= (uint64_t)v) {
goto overflow;
+ }
q = divlu64(u1, u0, v);
- diff = uneg ^ vneg; // Negate q if signs of
- q = (q ^ diff) - diff; // u and v differed.
+ diff = uneg ^ vneg; /* Negate q if signs of */
+ q = (q ^ diff) - diff; /* u and v differed. */
- if ((diff ^ q) < 0 && q != 0) { // If overflow, return the largest
- overflow: // possible neg. quotient.
+ if ((diff ^ q) < 0 && q != 0) { /* If overflow, return the
+ largest */
+ overflow: /* possible neg. quotient. */
q = 0x8000000000000000ULL;
}
return q;