X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftally%2Ftally.c;h=d9f30ba12f39cc87c94d2e0e12c4af23177b8add;hp=7eec70d39323429e259e08f04d195fd97472f57b;hb=4a4985d51c2272569534457388d6178072f36452;hpb=4f438157901f6784cd47135e50deb204fc0c230b diff --git a/ccan/tally/tally.c b/ccan/tally/tally.c index 7eec70d3..d9f30ba1 100644 --- a/ccan/tally/tally.c +++ b/ccan/tally/tally.c @@ -63,8 +63,9 @@ 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 == SIZET_BITS) + if (step_bits == SIZET_BITS) { return min; + } assert(step_bits < SIZET_BITS); return min + ((ssize_t)b << step_bits); } @@ -72,8 +73,9 @@ static ssize_t bucket_min(ssize_t min, unsigned step_bits, unsigned b) /* 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)); } @@ -86,8 +88,9 @@ static void renormalize(struct tally *tally, 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. */ @@ -135,15 +138,17 @@ void tally_add(struct tally *tally, ssize_t val) 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)]++; } @@ -151,8 +156,9 @@ void tally_add(struct tally *tally, ssize_t 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; } @@ -177,8 +183,9 @@ static unsigned fls64(uint64_t val) #endif uint64_t r = 64; - if (!val) + if (!val) { return 0; + } if (!(val & 0xffffffff00000000ull)) { val <<= 32; r -= 32; @@ -212,46 +219,49 @@ static unsigned fls64(uint64_t val) /* 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]; @@ -262,9 +272,9 @@ static uint64_t divlu64(uint64_t u1, uint64_t u0, uint64_t v) 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; @@ -273,7 +283,7 @@ static uint64_t divlu64(uint64_t u1, uint64_t u0, uint64_t v) } un[j+2] = un[j+2] + k; } - } // End j. + } /* End j. */ return q[1]*b + q[0]; }