func parseAdditionalSections(s *bufio.Scanner, p *Profile) error {
	for !isMemoryMapSentinel(s.Text()) && s.Scan() {
	}
	if err := s.Err(); err != nil {
		return err
	}
	return p.ParseMemoryMapFromScanner(s)
}
parseAdditionalSections parses any additional sections in the
profile, ignoring any unrecognized sections.
package profile
import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"math"
	"regexp"
	"strconv"
	"strings"
)
var (
	countStartRE = regexp.MustCompile(`\A(\S+) profile: total \d+\z`)
	countRE      = regexp.MustCompile(`\A(\d+) @(( 0x[0-9a-f]+)+)\z`)
	heapHeaderRE = regexp.MustCompile(`heap profile: *(\d+): *(\d+) *\[ *(\d+): *(\d+) *\] *@ *(heap[_a-z0-9]*)/?(\d*)`)
	heapSampleRE = regexp.MustCompile(`(-?\d+): *(-?\d+) *\[ *(\d+): *(\d+) *] @([ x0-9a-f]*)`)
	contentionSampleRE = regexp.MustCompile(`(\d+) *(\d+) @([ x0-9a-f]*)`)
	hexNumberRE = regexp.MustCompile(`0x[0-9a-f]+`)
	growthHeaderRE = regexp.MustCompile(`heap profile: *(\d+): *(\d+) *\[ *(\d+): *(\d+) *\] @ growthz?`)
	fragmentationHeaderRE = regexp.MustCompile(`heap profile: *(\d+): *(\d+) *\[ *(\d+): *(\d+) *\] @ fragmentationz?`)
	threadzStartRE = regexp.MustCompile(`--- threadz \d+ ---`)
	threadStartRE  = regexp.MustCompile(`--- Thread ([[:xdigit:]]+) \(name: (.*)/(\d+)\) stack: ---`)
	spaceDigits = `\s+[[:digit:]]+`
	hexPair     = `\s+[[:xdigit:]]+:[[:xdigit:]]+`
	oSpace      = `\s*`
	cHex           = `(?:0x)?([[:xdigit:]]+)`
	cHexRange      = `\s*` + cHex + `[\s-]?` + oSpace + cHex + `:?`
	cSpaceString   = `(?:\s+(\S+))?`
	cSpaceHex      = `(?:\s+([[:xdigit:]]+))?`
	cSpaceAtOffset = `(?:\s+\(@([[:xdigit:]]+)\))?`
	cPerm          = `(?:\s+([-rwxp]+))?`
	procMapsRE  = regexp.MustCompile(`^` + cHexRange + cPerm + cSpaceHex + hexPair + spaceDigits + cSpaceString)
	briefMapsRE = regexp.MustCompile(`^` + cHexRange + cPerm + cSpaceString + cSpaceAtOffset + cSpaceHex)
	logInfoRE = regexp.MustCompile(`^[^\[\]]+:[0-9]+]\s`)
)
func isSpaceOrComment(line string) bool {
	trimmed := strings.TrimSpace(line)
	return len(trimmed) == 0 || trimmed[0] == '#'
}
func parseGoCount(b []byte) (*Profile, error) {
	s := bufio.NewScanner(bytes.NewBuffer(b))
	for s.Scan() && isSpaceOrComment(s.Text()) {
	}
	if err := s.Err(); err != nil {
		return nil, err
	}
	m := countStartRE.FindStringSubmatch(s.Text())
	if m == nil {
		return nil, errUnrecognized
	}
	profileType := m[1]
	p := &Profile{
		PeriodType: &ValueType{Type: profileType, Unit: "count"},
		Period:     1,
		SampleType: []*ValueType{{Type: profileType, Unit: "count"}},
	}
	locations := make(map[uint64]*Location)
	for s.Scan() {
		line := s.Text()
		if isSpaceOrComment(line) {
			continue
		}
		if strings.HasPrefix(line, "---") {
			break
		}
		m := countRE.FindStringSubmatch(line)
		if m == nil {
			return nil, errMalformed
		}
		n, err := strconv.ParseInt(m[1], 0, 64)
		if err != nil {
			return nil, errMalformed
		}
		fields := strings.Fields(m[2])
		locs := make([]*Location, 0, len(fields))
		for _, stk := range fields {
			addr, err := strconv.ParseUint(stk, 0, 64)
			if err != nil {
				return nil, errMalformed
			}
			addr--
			loc := locations[addr]
			if loc == nil {
				loc = &Location{
					Address: addr,
				}
				locations[addr] = loc
				p.Location = append(p.Location, loc)
			}
			locs = append(locs, loc)
		}
		p.Sample = append(p.Sample, &Sample{
			Location: locs,
			Value:    []int64{n},
		})
	}
	if err := s.Err(); err != nil {
		return nil, err
	}
	if err := parseAdditionalSections(s, p); err != nil {
		return nil, err
	}
	return p, nil
}
func (p *Profile) remapLocationIDs() {
	seen := make(map[*Location]bool, len(p.Location))
	var locs []*Location
	for _, s := range p.Sample {
		for _, l := range s.Location {
			if seen[l] {
				continue
			}
			l.ID = uint64(len(locs) + 1)
			locs = append(locs, l)
			seen[l] = true
		}
	}
	p.Location = locs
}
func (p *Profile) remapFunctionIDs() {
	seen := make(map[*Function]bool, len(p.Function))
	var fns []*Function
	for _, l := range p.Location {
		for _, ln := range l.Line {
			fn := ln.Function
			if fn == nil || seen[fn] {
				continue
			}
			fn.ID = uint64(len(fns) + 1)
			fns = append(fns, fn)
			seen[fn] = true
		}
	}
	p.Function = fns
}
func (p *Profile) remapMappingIDs() {
	if len(p.Mapping) > 0 {
		if m := p.Mapping[0]; strings.HasPrefix(m.File, "/anon_hugepage") {
			if len(p.Mapping) > 1 && m.Limit == p.Mapping[1].Start {
				p.Mapping = p.Mapping[1:]
			}
		}
	}
	if len(p.Mapping) > 0 {
		const expectedStart = 0x400000
		if m := p.Mapping[0]; m.Start-m.Offset == expectedStart {
			m.Start = expectedStart
			m.Offset = 0
		}
	}
	var fake *Mapping
nextLocation:
	for _, l := range p.Location {
		a := l.Address
		if l.Mapping != nil || a == 0 {
			continue
		}
		for _, m := range p.Mapping {
			if m.Start <= a && a < m.Limit {
				l.Mapping = m
				continue nextLocation
			}
		}
		for _, m := range p.Mapping {
			if m.Offset != 0 && m.Start-m.Offset <= a && a < m.Start {
				m.Start -= m.Offset
				m.Offset = 0
				l.Mapping = m
				continue nextLocation
			}
		}
		if fake == nil {
			fake = &Mapping{
				ID:    1,
				Limit: ^uint64(0),
			}
			p.Mapping = append(p.Mapping, fake)
		}
		l.Mapping = fake
	}
	for i, m := range p.Mapping {
		m.ID = uint64(i + 1)
	}
}
var cpuInts = []func([]byte) (uint64, []byte){
	get32l,
	get32b,
	get64l,
	get64b,
}
func get32l(b []byte) (uint64, []byte) {
	if len(b) < 4 {
		return 0, nil
	}
	return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24, b[4:]
}
func get32b(b []byte) (uint64, []byte) {
	if len(b) < 4 {
		return 0, nil
	}
	return uint64(b[3]) | uint64(b[2])<<8 | uint64(b[1])<<16 | uint64(b[0])<<24, b[4:]
}
func get64l(b []byte) (uint64, []byte) {
	if len(b) < 8 {
		return 0, nil
	}
	return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56, b[8:]
}
func get64b(b []byte) (uint64, []byte) {
	if len(b) < 8 {
		return 0, nil
	}
	return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 | uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56, b[8:]
}
func parseCPU(b []byte) (*Profile, error) {
	var parse func([]byte) (uint64, []byte)
	var n1, n2, n3, n4, n5 uint64
	for _, parse = range cpuInts {
		var tmp []byte
		n1, tmp = parse(b)
		n2, tmp = parse(tmp)
		n3, tmp = parse(tmp)
		n4, tmp = parse(tmp)
		n5, tmp = parse(tmp)
		if tmp != nil && n1 == 0 && n2 == 3 && n3 == 0 && n4 > 0 && n5 == 0 {
			b = tmp
			return cpuProfile(b, int64(n4), parse)
		}
		if tmp != nil && n1 == 0 && n2 == 3 && n3 == 1 && n4 > 0 && n5 == 0 {
			b = tmp
			return javaCPUProfile(b, int64(n4), parse)
		}
	}
	return nil, errUnrecognized
}
func cpuProfile(b []byte, period int64, parse func(b []byte) (uint64, []byte)) (*Profile, error) {
	p := &Profile{
		Period:     period * 1000,
		PeriodType: &ValueType{Type: "cpu", Unit: "nanoseconds"},
		SampleType: []*ValueType{
			{Type: "samples", Unit: "count"},
			{Type: "cpu", Unit: "nanoseconds"},
		},
	}
	var err error
	if b, _, err = parseCPUSamples(b, parse, true, p); err != nil {
		return nil, err
	}
	maxiter := 2
	similarSamples := 32
	margin := len(p.Sample) / similarSamples
	for iter := 0; iter < maxiter; iter++ {
		addr1 := make(map[uint64]int)
		for _, s := range p.Sample {
			if len(s.Location) > 1 {
				a := s.Location[1].Address
				addr1[a] = addr1[a] + 1
			}
		}
		for id1, count := range addr1 {
			if count >= len(p.Sample)-margin {
				for _, s := range p.Sample {
					if len(s.Location) > 1 && s.Location[1].Address == id1 {
						s.Location = append(s.Location[:1], s.Location[2:]...)
					}
				}
				break
			}
		}
	}
	if err := p.ParseMemoryMap(bytes.NewBuffer(b)); err != nil {
		return nil, err
	}
	cleanupDuplicateLocations(p)
	return p, nil
}
func cleanupDuplicateLocations(p *Profile) {
	for _, s := range p.Sample {
		if len(s.Location) > 1 && s.Location[0].Address == s.Location[1].Address+1 {
			s.Location = append(s.Location[:1], s.Location[2:]...)
		}
	}
}
func parseCPUSamples(b []byte, parse func(b []byte) (uint64, []byte), adjust bool, p *Profile) ([]byte, map[uint64]*Location, error) {
	locs := make(map[uint64]*Location)
	for len(b) > 0 {
		var count, nstk uint64
		count, b = parse(b)
		nstk, b = parse(b)
		if b == nil || nstk > uint64(len(b)/4) {
			return nil, nil, errUnrecognized
		}
		var sloc []*Location
		addrs := make([]uint64, nstk)
		for i := 0; i < int(nstk); i++ {
			addrs[i], b = parse(b)
		}
		if count == 0 && nstk == 1 && addrs[0] == 0 {
			break
		}
		for i, addr := range addrs {
			if adjust && i > 0 {
				addr--
			}
			loc := locs[addr]
			if loc == nil {
				loc = &Location{
					Address: addr,
				}
				locs[addr] = loc
				p.Location = append(p.Location, loc)
			}
			sloc = append(sloc, loc)
		}
		p.Sample = append(p.Sample,
			&Sample{
				Value:    []int64{int64(count), int64(count) * p.Period},
				Location: sloc,
			})
	}
	return b, locs, nil
}
func parseHeap(b []byte) (p *Profile, err error) {
	s := bufio.NewScanner(bytes.NewBuffer(b))
	if !s.Scan() {
		if err := s.Err(); err != nil {
			return nil, err
		}
		return nil, errUnrecognized
	}
	p = &Profile{}
	sampling := ""
	hasAlloc := false
	line := s.Text()
	p.PeriodType = &ValueType{Type: "space", Unit: "bytes"}
	if header := heapHeaderRE.FindStringSubmatch(line); header != nil {
		sampling, p.Period, hasAlloc, err = parseHeapHeader(line)
		if err != nil {
			return nil, err
		}
	} else if header = growthHeaderRE.FindStringSubmatch(line); header != nil {
		p.Period = 1
	} else if header = fragmentationHeaderRE.FindStringSubmatch(line); header != nil {
		p.Period = 1
	} else {
		return nil, errUnrecognized
	}
	if hasAlloc {
		p.SampleType = []*ValueType{
			{Type: "alloc_objects", Unit: "count"},
			{Type: "alloc_space", Unit: "bytes"},
			{Type: "inuse_objects", Unit: "count"},
			{Type: "inuse_space", Unit: "bytes"},
		}
	} else {
		p.SampleType = []*ValueType{
			{Type: "objects", Unit: "count"},
			{Type: "space", Unit: "bytes"},
		}
	}
	locs := make(map[uint64]*Location)
	for s.Scan() {
		line := strings.TrimSpace(s.Text())
		if isSpaceOrComment(line) {
			continue
		}
		if isMemoryMapSentinel(line) {
			break
		}
		value, blocksize, addrs, err := parseHeapSample(line, p.Period, sampling, hasAlloc)
		if err != nil {
			return nil, err
		}
		var sloc []*Location
		for _, addr := range addrs {
			addr--
			loc := locs[addr]
			if locs[addr] == nil {
				loc = &Location{
					Address: addr,
				}
				p.Location = append(p.Location, loc)
				locs[addr] = loc
			}
			sloc = append(sloc, loc)
		}
		p.Sample = append(p.Sample, &Sample{
			Value:    value,
			Location: sloc,
			NumLabel: map[string][]int64{"bytes": {blocksize}},
		})
	}
	if err := s.Err(); err != nil {
		return nil, err
	}
	if err := parseAdditionalSections(s, p); err != nil {
		return nil, err
	}
	return p, nil
}
func parseHeapHeader(line string) (sampling string, period int64, hasAlloc bool, err error) {
	header := heapHeaderRE.FindStringSubmatch(line)
	if header == nil {
		return "", 0, false, errUnrecognized
	}
	if len(header[6]) > 0 {
		if period, err = strconv.ParseInt(header[6], 10, 64); err != nil {
			return "", 0, false, errUnrecognized
		}
	}
	if (header[3] != header[1] && header[3] != "0") || (header[4] != header[2] && header[4] != "0") {
		hasAlloc = true
	}
	switch header[5] {
	case "heapz_v2", "heap_v2":
		return "v2", period, hasAlloc, nil
	case "heapprofile":
		return "", 1, hasAlloc, nil
	case "heap":
		return "v2", period / 2, hasAlloc, nil
	default:
		return "", 0, false, errUnrecognized
	}
}
func parseHeapSample(line string, rate int64, sampling string, includeAlloc bool) (value []int64, blocksize int64, addrs []uint64, err error) {
	sampleData := heapSampleRE.FindStringSubmatch(line)
	if len(sampleData) != 6 {
		return nil, 0, nil, fmt.Errorf("unexpected number of sample values: got %d, want 6", len(sampleData))
	}
	addValues := func(countString, sizeString string, label string) error {
		count, err := strconv.ParseInt(countString, 10, 64)
		if err != nil {
			return fmt.Errorf("malformed sample: %s: %v", line, err)
		}
		size, err := strconv.ParseInt(sizeString, 10, 64)
		if err != nil {
			return fmt.Errorf("malformed sample: %s: %v", line, err)
		}
		if count == 0 && size != 0 {
			return fmt.Errorf("%s count was 0 but %s bytes was %d", label, label, size)
		}
		if count != 0 {
			blocksize = size / count
			if sampling == "v2" {
				count, size = scaleHeapSample(count, size, rate)
			}
		}
		value = append(value, count, size)
		return nil
	}
	if includeAlloc {
		if err := addValues(sampleData[3], sampleData[4], "allocation"); err != nil {
			return nil, 0, nil, err
		}
	}
	if err := addValues(sampleData[1], sampleData[2], "inuse"); err != nil {
		return nil, 0, nil, err
	}
	addrs, err = parseHexAddresses(sampleData[5])
	if err != nil {
		return nil, 0, nil, fmt.Errorf("malformed sample: %s: %v", line, err)
	}
	return value, blocksize, addrs, nil
}
func parseHexAddresses(s string) ([]uint64, error) {
	hexStrings := hexNumberRE.FindAllString(s, -1)
	var addrs []uint64
	for _, s := range hexStrings {
		if addr, err := strconv.ParseUint(s, 0, 64); err == nil {
			addrs = append(addrs, addr)
		} else {
			return nil, fmt.Errorf("failed to parse as hex 64-bit number: %s", s)
		}
	}
	return addrs, nil
}
func scaleHeapSample(count, size, rate int64) (int64, int64) {
	if count == 0 || size == 0 {
		return 0, 0
	}
	if rate <= 1 {
		return count, size
	}
	avgSize := float64(size) / float64(count)
	scale := 1 / (1 - math.Exp(-avgSize/float64(rate)))
	return int64(float64(count) * scale), int64(float64(size) * scale)
}
func parseContention(b []byte) (*Profile, error) {
	s := bufio.NewScanner(bytes.NewBuffer(b))
	if !s.Scan() {
		if err := s.Err(); err != nil {
			return nil, err
		}
		return nil, errUnrecognized
	}
	switch l := s.Text(); {
	case strings.HasPrefix(l, "--- contentionz "):
	case strings.HasPrefix(l, "--- mutex:"):
	case strings.HasPrefix(l, "--- contention:"):
	default:
		return nil, errUnrecognized
	}
	p := &Profile{
		PeriodType: &ValueType{Type: "contentions", Unit: "count"},
		Period:     1,
		SampleType: []*ValueType{
			{Type: "contentions", Unit: "count"},
			{Type: "delay", Unit: "nanoseconds"},
		},
	}
	var cpuHz int64
	const delimiter = "="
	for s.Scan() {
		line := s.Text()
		if line = strings.TrimSpace(line); isSpaceOrComment(line) {
			continue
		}
		if strings.HasPrefix(line, "---") {
			break
		}
		attr := strings.SplitN(line, delimiter, 2)
		if len(attr) != 2 {
			break
		}
		key, val := strings.TrimSpace(attr[0]), strings.TrimSpace(attr[1])
		var err error
		switch key {
		case "cycles/second":
			if cpuHz, err = strconv.ParseInt(val, 0, 64); err != nil {
				return nil, errUnrecognized
			}
		case "sampling period":
			if p.Period, err = strconv.ParseInt(val, 0, 64); err != nil {
				return nil, errUnrecognized
			}
		case "ms since reset":
			ms, err := strconv.ParseInt(val, 0, 64)
			if err != nil {
				return nil, errUnrecognized
			}
			p.DurationNanos = ms * 1000 * 1000
		case "format":
			return nil, errUnrecognized
		case "resolution":
			return nil, errUnrecognized
		case "discarded samples":
		default:
			return nil, errUnrecognized
		}
	}
	if err := s.Err(); err != nil {
		return nil, err
	}
	locs := make(map[uint64]*Location)
	for {
		line := strings.TrimSpace(s.Text())
		if strings.HasPrefix(line, "---") {
			break
		}
		if !isSpaceOrComment(line) {
			value, addrs, err := parseContentionSample(line, p.Period, cpuHz)
			if err != nil {
				return nil, err
			}
			var sloc []*Location
			for _, addr := range addrs {
				addr--
				loc := locs[addr]
				if locs[addr] == nil {
					loc = &Location{
						Address: addr,
					}
					p.Location = append(p.Location, loc)
					locs[addr] = loc
				}
				sloc = append(sloc, loc)
			}
			p.Sample = append(p.Sample, &Sample{
				Value:    value,
				Location: sloc,
			})
		}
		if !s.Scan() {
			break
		}
	}
	if err := s.Err(); err != nil {
		return nil, err
	}
	if err := parseAdditionalSections(s, p); err != nil {
		return nil, err
	}
	return p, nil
}
func parseContentionSample(line string, period, cpuHz int64) (value []int64, addrs []uint64, err error) {
	sampleData := contentionSampleRE.FindStringSubmatch(line)
	if sampleData == nil {
		return nil, nil, errUnrecognized
	}
	v1, err := strconv.ParseInt(sampleData[1], 10, 64)
	if err != nil {
		return nil, nil, fmt.Errorf("malformed sample: %s: %v", line, err)
	}
	v2, err := strconv.ParseInt(sampleData[2], 10, 64)
	if err != nil {
		return nil, nil, fmt.Errorf("malformed sample: %s: %v", line, err)
	}
	if period > 0 {
		if cpuHz > 0 {
			cpuGHz := float64(cpuHz) / 1e9
			v1 = int64(float64(v1) * float64(period) / cpuGHz)
		}
		v2 = v2 * period
	}
	value = []int64{v2, v1}
	addrs, err = parseHexAddresses(sampleData[3])
	if err != nil {
		return nil, nil, fmt.Errorf("malformed sample: %s: %v", line, err)
	}
	return value, addrs, nil
}
func parseThread(b []byte) (*Profile, error) {
	s := bufio.NewScanner(bytes.NewBuffer(b))
	for s.Scan() && isSpaceOrComment(s.Text()) {
	}
	line := s.Text()
	if m := threadzStartRE.FindStringSubmatch(line); m != nil {
		for s.Scan() {
			if line = s.Text(); isMemoryMapSentinel(line) || strings.HasPrefix(line, "-") {
				break
			}
		}
	} else if t := threadStartRE.FindStringSubmatch(line); len(t) != 4 {
		return nil, errUnrecognized
	}
	p := &Profile{
		SampleType: []*ValueType{{Type: "thread", Unit: "count"}},
		PeriodType: &ValueType{Type: "thread", Unit: "count"},
		Period:     1,
	}
	locs := make(map[uint64]*Location)
	for !isMemoryMapSentinel(line) {
		if strings.HasPrefix(line, "---- no stack trace for") {
			line = ""
			break
		}
		if t := threadStartRE.FindStringSubmatch(line); len(t) != 4 {
			return nil, errUnrecognized
		}
		var addrs []uint64
		var err error
		line, addrs, err = parseThreadSample(s)
		if err != nil {
			return nil, err
		}
		if len(addrs) == 0 {
			if len(p.Sample) > 0 {
				s := p.Sample[len(p.Sample)-1]
				s.Value[0]++
			}
			continue
		}
		var sloc []*Location
		for i, addr := range addrs {
			if i > 0 {
				addr--
			}
			loc := locs[addr]
			if locs[addr] == nil {
				loc = &Location{
					Address: addr,
				}
				p.Location = append(p.Location, loc)
				locs[addr] = loc
			}
			sloc = append(sloc, loc)
		}
		p.Sample = append(p.Sample, &Sample{
			Value:    []int64{1},
			Location: sloc,
		})
	}
	if err := parseAdditionalSections(s, p); err != nil {
		return nil, err
	}
	cleanupDuplicateLocations(p)
	return p, nil
}
func parseThreadSample(s *bufio.Scanner) (nextl string, addrs []uint64, err error) {
	var line string
	sameAsPrevious := false
	for s.Scan() {
		line = strings.TrimSpace(s.Text())
		if line == "" {
			continue
		}
		if strings.HasPrefix(line, "---") {
			break
		}
		if strings.Contains(line, "same as previous thread") {
			sameAsPrevious = true
			continue
		}
		curAddrs, err := parseHexAddresses(line)
		if err != nil {
			return "", nil, fmt.Errorf("malformed sample: %s: %v", line, err)
		}
		addrs = append(addrs, curAddrs...)
	}
	if err := s.Err(); err != nil {
		return "", nil, err
	}
	if sameAsPrevious {
		return line, nil, nil
	}
	return line, addrs, nil
}