// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package runtime

// fastlog2 implements a fast approximation to the base 2 log of a
// float64. This is used to compute a geometric distribution for heap
// sampling, without introducing dependencies into package math. This
// uses a very rough approximation using the float64 exponent and the

	// Compute the euclidean distance between math.Log2 and the FastLog2
	// implementation over the range of interest for heap sampling.
	const randomBitCount = 26
	var e float64

	inc := 1
	if testing.Short() {
		// Check 1K total values, down from 64M.
		inc = 1 << 16
	}
	for i := 1; i < 1<<randomBitCount; i += inc {
		l, fl := math.Log2(float64(i)), runtime.Fastlog2(float64(i))
		d := l - fl
		e += d * d
	}

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build ignore

// fastlog2Table contains log2 approximations for 5 binary digits.
// This is used to implement fastlog2, which is used for heap sampling.

package main

import (
	"bytes"
	"fmt"
	"log"
	"math"
	"os"
)

func main() {
	var buf bytes.Buffer

			"add",
			"acquirem",
			"add1",
			"addb",
			"adjustpanics",
			"adjustpointer",
			"alignDown",
			"alignUp",
			"bucketMask",
			"bucketShift",
			"chanbuf",
			"evacuated",
			"fastlog2",
			"float64bits",
			"funcspdelta",
			"getm",
			"getMCache",
			"isDirectIface",
			"itabHashFunc",
			"nextslicecap",
			"noescape",
			"pcvalueCacheKey",
			"rand32",
			"readUnaligned32",

var F64toint = f64toint

var Entersyscall = entersyscall
var Exitsyscall = exitsyscall
var LockedOSThread = lockedOSThread
var Xadduintptr = atomic.Xadduintptr

var ReadRandomFailed = &readRandomFailed

var Fastlog2 = fastlog2

var Atoi = atoi
var Atoi32 = atoi32
var ParseByteCount = parseByteCount

var Nanotime = nanotime
var NetpollBreak = netpollBreak
var Usleep = usleep

var PhysPageSize = physPageSize

	// -log_e(q)/mean = x
	// x = -log_e(q) * mean
	// x = log_2(q) * (-log_e(2)) * mean    ; Using log_2 for efficiency
	const randomBitCount = 26
	q := cheaprandn(1<<randomBitCount) + 1
	qlog := fastlog2(float64(q)) - randomBitCount
	if qlog > 0 {
		qlog = 0
	}
	const minusLog2 = -0.6931471805599453 // -ln(2)
	return int32(qlog*(minusLog2*float64(mean))) + 1
}

	updates := make(chan v1.Update, 1000)
	go func() {
		lastLog := time.Time{}
		for u := range updates {
			if time.Since(lastLog) < time.Second && !(u.Total == u.Complete) {
				// Limit to 1 log per-image per-second, unless it is the final log
				continue
			}
			if u.Total == 0 {
				continue
			}
			lastLog = time.Now()

+#define UT_LINESIZE	32
+#define UT_NAMESIZE	32
+#define UT_HOSTSIZE	256
 
 
+/* The structure describing an entry in the database of
+   previous logins.  */
 struct lastlog
   {
     time_t ll_time;
@@ -36,12 +38,16 @@ struct lastlog
     char ll_host[UT_HOSTSIZE];
   };
 
+/* The structure describing an entry in the user accounting database.  */
 struct utmp
   {
-    char ut_line[UT_LINESIZE];

	}
	for i := 0; i < len(vflogSC); i++ {
		if f := Log1p(vflog1pSC[i]); !alike(log1pSC[i], f) {
			t.Errorf("Log1p(%g) = %g, want %g", vflog1pSC[i], f, log1pSC[i])
		}
	}
}

func TestLog2(t *testing.T) {
	for i := 0; i < len(vf); i++ {
		a := Abs(vf[i])
		if f := Log2(a); !veryclose(log2[i], f) {
			t.Errorf("Log2(%g) = %g, want %g", a, f, log2[i])
		}
	}
	if f := Log2(E); f != Log2E {