Adding upstream version 1.20.14.upstream/1.20.14upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1226 insertions, 0 deletions

diff --git a/src/fmt/print.go b/src/fmt/print.go
new file mode 100644
index 0000000..b3dd43c
--- /dev/null
+++ b/src/fmt/print.go
@@ -0,0 +1,1226 @@
+// Copyright 2009 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 fmt
+
+import (
+	"internal/fmtsort"
+	"io"
+	"os"
+	"reflect"
+	"strconv"
+	"sync"
+	"unicode/utf8"
+)
+
+// Strings for use with buffer.WriteString.
+// This is less overhead than using buffer.Write with byte arrays.
+const (
+	commaSpaceString  = ", "
+	nilAngleString    = "<nil>"
+	nilParenString    = "(nil)"
+	nilString         = "nil"
+	mapString         = "map["
+	percentBangString = "%!"
+	missingString     = "(MISSING)"
+	badIndexString    = "(BADINDEX)"
+	panicString       = "(PANIC="
+	extraString       = "%!(EXTRA "
+	badWidthString    = "%!(BADWIDTH)"
+	badPrecString     = "%!(BADPREC)"
+	noVerbString      = "%!(NOVERB)"
+	invReflectString  = "<invalid reflect.Value>"
+)
+
+// State represents the printer state passed to custom formatters.
+// It provides access to the io.Writer interface plus information about
+// the flags and options for the operand's format specifier.
+type State interface {
+	// Write is the function to call to emit formatted output to be printed.
+	Write(b []byte) (n int, err error)
+	// Width returns the value of the width option and whether it has been set.
+	Width() (wid int, ok bool)
+	// Precision returns the value of the precision option and whether it has been set.
+	Precision() (prec int, ok bool)
+
+	// Flag reports whether the flag c, a character, has been set.
+	Flag(c int) bool
+}
+
+// Formatter is implemented by any value that has a Format method.
+// The implementation controls how State and rune are interpreted,
+// and may call Sprint(f) or Fprint(f) etc. to generate its output.
+type Formatter interface {
+	Format(f State, verb rune)
+}
+
+// Stringer is implemented by any value that has a String method,
+// which defines the “native” format for that value.
+// The String method is used to print values passed as an operand
+// to any format that accepts a string or to an unformatted printer
+// such as Print.
+type Stringer interface {
+	String() string
+}
+
+// GoStringer is implemented by any value that has a GoString method,
+// which defines the Go syntax for that value.
+// The GoString method is used to print values passed as an operand
+// to a %#v format.
+type GoStringer interface {
+	GoString() string
+}
+
+// FormatString returns a string representing the fully qualified formatting
+// directive captured by the State, followed by the argument verb. (State does not
+// itself contain the verb.) The result has a leading percent sign followed by any
+// flags, the width, and the precision. Missing flags, width, and precision are
+// omitted. This function allows a Formatter to reconstruct the original
+// directive triggering the call to Format.
+func FormatString(state State, verb rune) string {
+	var tmp [16]byte // Use a local buffer.
+	b := append(tmp[:0], '%')
+	for _, c := range " +-#0" { // All known flags
+		if state.Flag(int(c)) { // The argument is an int for historical reasons.
+			b = append(b, byte(c))
+		}
+	}
+	if w, ok := state.Width(); ok {
+		b = strconv.AppendInt(b, int64(w), 10)
+	}
+	if p, ok := state.Precision(); ok {
+		b = append(b, '.')
+		b = strconv.AppendInt(b, int64(p), 10)
+	}
+	b = utf8.AppendRune(b, verb)
+	return string(b)
+}
+
+// Use simple []byte instead of bytes.Buffer to avoid large dependency.
+type buffer []byte
+
+func (b *buffer) write(p []byte) {
+	*b = append(*b, p...)
+}
+
+func (b *buffer) writeString(s string) {
+	*b = append(*b, s...)
+}
+
+func (b *buffer) writeByte(c byte) {
+	*b = append(*b, c)
+}
+
+func (bp *buffer) writeRune(r rune) {
+	*bp = utf8.AppendRune(*bp, r)
+}
+
+// pp is used to store a printer's state and is reused with sync.Pool to avoid allocations.
+type pp struct {
+	buf buffer
+
+	// arg holds the current item, as an interface{}.
+	arg any
+
+	// value is used instead of arg for reflect values.
+	value reflect.Value
+
+	// fmt is used to format basic items such as integers or strings.
+	fmt fmt
+
+	// reordered records whether the format string used argument reordering.
+	reordered bool
+	// goodArgNum records whether the most recent reordering directive was valid.
+	goodArgNum bool
+	// panicking is set by catchPanic to avoid infinite panic, recover, panic, ... recursion.
+	panicking bool
+	// erroring is set when printing an error string to guard against calling handleMethods.
+	erroring bool
+	// wrapErrs is set when the format string may contain a %w verb.
+	wrapErrs bool
+	// wrappedErrs records the targets of the %w verb.
+	wrappedErrs []int
+}
+
+var ppFree = sync.Pool{
+	New: func() any { return new(pp) },
+}
+
+// newPrinter allocates a new pp struct or grabs a cached one.
+func newPrinter() *pp {
+	p := ppFree.Get().(*pp)
+	p.panicking = false
+	p.erroring = false
+	p.wrapErrs = false
+	p.fmt.init(&p.buf)
+	return p
+}
+
+// free saves used pp structs in ppFree; avoids an allocation per invocation.
+func (p *pp) free() {
+	// Proper usage of a sync.Pool requires each entry to have approximately
+	// the same memory cost. To obtain this property when the stored type
+	// contains a variably-sized buffer, we add a hard limit on the maximum
+	// buffer to place back in the pool. If the buffer is larger than the
+	// limit, we drop the buffer and recycle just the printer.
+	//
+	// See https://golang.org/issue/23199.
+	if cap(p.buf) > 64*1024 {
+		p.buf = nil
+	} else {
+		p.buf = p.buf[:0]
+	}
+	if cap(p.wrappedErrs) > 8 {
+		p.wrappedErrs = nil
+	}
+
+	p.arg = nil
+	p.value = reflect.Value{}
+	p.wrappedErrs = p.wrappedErrs[:0]
+	ppFree.Put(p)
+}
+
+func (p *pp) Width() (wid int, ok bool) { return p.fmt.wid, p.fmt.widPresent }
+
+func (p *pp) Precision() (prec int, ok bool) { return p.fmt.prec, p.fmt.precPresent }
+
+func (p *pp) Flag(b int) bool {
+	switch b {
+	case '-':
+		return p.fmt.minus
+	case '+':
+		return p.fmt.plus || p.fmt.plusV
+	case '#':
+		return p.fmt.sharp || p.fmt.sharpV
+	case ' ':
+		return p.fmt.space
+	case '0':
+		return p.fmt.zero
+	}
+	return false
+}
+
+// Implement Write so we can call Fprintf on a pp (through State), for
+// recursive use in custom verbs.
+func (p *pp) Write(b []byte) (ret int, err error) {
+	p.buf.write(b)
+	return len(b), nil
+}
+
+// Implement WriteString so that we can call io.WriteString
+// on a pp (through state), for efficiency.
+func (p *pp) WriteString(s string) (ret int, err error) {
+	p.buf.writeString(s)
+	return len(s), nil
+}
+
+// These routines end in 'f' and take a format string.
+
+// Fprintf formats according to a format specifier and writes to w.
+// It returns the number of bytes written and any write error encountered.
+func Fprintf(w io.Writer, format string, a ...any) (n int, err error) {
+	p := newPrinter()
+	p.doPrintf(format, a)
+	n, err = w.Write(p.buf)
+	p.free()
+	return
+}
+
+// Printf formats according to a format specifier and writes to standard output.
+// It returns the number of bytes written and any write error encountered.
+func Printf(format string, a ...any) (n int, err error) {
+	return Fprintf(os.Stdout, format, a...)
+}
+
+// Sprintf formats according to a format specifier and returns the resulting string.
+func Sprintf(format string, a ...any) string {
+	p := newPrinter()
+	p.doPrintf(format, a)
+	s := string(p.buf)
+	p.free()
+	return s
+}
+
+// Appendf formats according to a format specifier, appends the result to the byte
+// slice, and returns the updated slice.
+func Appendf(b []byte, format string, a ...any) []byte {
+	p := newPrinter()
+	p.doPrintf(format, a)
+	b = append(b, p.buf...)
+	p.free()
+	return b
+}
+
+// These routines do not take a format string
+
+// Fprint formats using the default formats for its operands and writes to w.
+// Spaces are added between operands when neither is a string.
+// It returns the number of bytes written and any write error encountered.
+func Fprint(w io.Writer, a ...any) (n int, err error) {
+	p := newPrinter()
+	p.doPrint(a)
+	n, err = w.Write(p.buf)
+	p.free()
+	return
+}
+
+// Print formats using the default formats for its operands and writes to standard output.
+// Spaces are added between operands when neither is a string.
+// It returns the number of bytes written and any write error encountered.
+func Print(a ...any) (n int, err error) {
+	return Fprint(os.Stdout, a...)
+}
+
+// Sprint formats using the default formats for its operands and returns the resulting string.
+// Spaces are added between operands when neither is a string.
+func Sprint(a ...any) string {
+	p := newPrinter()
+	p.doPrint(a)
+	s := string(p.buf)
+	p.free()
+	return s
+}
+
+// Append formats using the default formats for its operands, appends the result to
+// the byte slice, and returns the updated slice.
+func Append(b []byte, a ...any) []byte {
+	p := newPrinter()
+	p.doPrint(a)
+	b = append(b, p.buf...)
+	p.free()
+	return b
+}
+
+// These routines end in 'ln', do not take a format string,
+// always add spaces between operands, and add a newline
+// after the last operand.
+
+// Fprintln formats using the default formats for its operands and writes to w.
+// Spaces are always added between operands and a newline is appended.
+// It returns the number of bytes written and any write error encountered.
+func Fprintln(w io.Writer, a ...any) (n int, err error) {
+	p := newPrinter()
+	p.doPrintln(a)
+	n, err = w.Write(p.buf)
+	p.free()
+	return
+}
+
+// Println formats using the default formats for its operands and writes to standard output.
+// Spaces are always added between operands and a newline is appended.
+// It returns the number of bytes written and any write error encountered.
+func Println(a ...any) (n int, err error) {
+	return Fprintln(os.Stdout, a...)
+}
+
+// Sprintln formats using the default formats for its operands and returns the resulting string.
+// Spaces are always added between operands and a newline is appended.
+func Sprintln(a ...any) string {
+	p := newPrinter()
+	p.doPrintln(a)
+	s := string(p.buf)
+	p.free()
+	return s
+}
+
+// Appendln formats using the default formats for its operands, appends the result
+// to the byte slice, and returns the updated slice. Spaces are always added
+// between operands and a newline is appended.
+func Appendln(b []byte, a ...any) []byte {
+	p := newPrinter()
+	p.doPrintln(a)
+	b = append(b, p.buf...)
+	p.free()
+	return b
+}
+
+// getField gets the i'th field of the struct value.
+// If the field is itself is an interface, return a value for
+// the thing inside the interface, not the interface itself.
+func getField(v reflect.Value, i int) reflect.Value {
+	val := v.Field(i)
+	if val.Kind() == reflect.Interface && !val.IsNil() {
+		val = val.Elem()
+	}
+	return val
+}
+
+// tooLarge reports whether the magnitude of the integer is
+// too large to be used as a formatting width or precision.
+func tooLarge(x int) bool {
+	const max int = 1e6
+	return x > max || x < -max
+}
+
+// parsenum converts ASCII to integer.  num is 0 (and isnum is false) if no number present.
+func parsenum(s string, start, end int) (num int, isnum bool, newi int) {
+	if start >= end {
+		return 0, false, end
+	}
+	for newi = start; newi < end && '0' <= s[newi] && s[newi] <= '9'; newi++ {
+		if tooLarge(num) {
+			return 0, false, end // Overflow; crazy long number most likely.
+		}
+		num = num*10 + int(s[newi]-'0')
+		isnum = true
+	}
+	return
+}
+
+func (p *pp) unknownType(v reflect.Value) {
+	if !v.IsValid() {
+		p.buf.writeString(nilAngleString)
+		return
+	}
+	p.buf.writeByte('?')
+	p.buf.writeString(v.Type().String())
+	p.buf.writeByte('?')
+}
+
+func (p *pp) badVerb(verb rune) {
+	p.erroring = true
+	p.buf.writeString(percentBangString)
+	p.buf.writeRune(verb)
+	p.buf.writeByte('(')
+	switch {
+	case p.arg != nil:
+		p.buf.writeString(reflect.TypeOf(p.arg).String())
+		p.buf.writeByte('=')
+		p.printArg(p.arg, 'v')
+	case p.value.IsValid():
+		p.buf.writeString(p.value.Type().String())
+		p.buf.writeByte('=')
+		p.printValue(p.value, 'v', 0)
+	default:
+		p.buf.writeString(nilAngleString)
+	}
+	p.buf.writeByte(')')
+	p.erroring = false
+}
+
+func (p *pp) fmtBool(v bool, verb rune) {
+	switch verb {
+	case 't', 'v':
+		p.fmt.fmtBoolean(v)
+	default:
+		p.badVerb(verb)
+	}
+}
+
+// fmt0x64 formats a uint64 in hexadecimal and prefixes it with 0x or
+// not, as requested, by temporarily setting the sharp flag.
+func (p *pp) fmt0x64(v uint64, leading0x bool) {
+	sharp := p.fmt.sharp
+	p.fmt.sharp = leading0x
+	p.fmt.fmtInteger(v, 16, unsigned, 'v', ldigits)
+	p.fmt.sharp = sharp
+}
+
+// fmtInteger formats a signed or unsigned integer.
+func (p *pp) fmtInteger(v uint64, isSigned bool, verb rune) {
+	switch verb {
+	case 'v':
+		if p.fmt.sharpV && !isSigned {
+			p.fmt0x64(v, true)
+		} else {
+			p.fmt.fmtInteger(v, 10, isSigned, verb, ldigits)
+		}
+	case 'd':
+		p.fmt.fmtInteger(v, 10, isSigned, verb, ldigits)
+	case 'b':
+		p.fmt.fmtInteger(v, 2, isSigned, verb, ldigits)
+	case 'o', 'O':
+		p.fmt.fmtInteger(v, 8, isSigned, verb, ldigits)
+	case 'x':
+		p.fmt.fmtInteger(v, 16, isSigned, verb, ldigits)
+	case 'X':
+		p.fmt.fmtInteger(v, 16, isSigned, verb, udigits)
+	case 'c':
+		p.fmt.fmtC(v)
+	case 'q':
+		p.fmt.fmtQc(v)
+	case 'U':
+		p.fmt.fmtUnicode(v)
+	default:
+		p.badVerb(verb)
+	}
+}
+
+// fmtFloat formats a float. The default precision for each verb
+// is specified as last argument in the call to fmt_float.
+func (p *pp) fmtFloat(v float64, size int, verb rune) {
+	switch verb {
+	case 'v':
+		p.fmt.fmtFloat(v, size, 'g', -1)
+	case 'b', 'g', 'G', 'x', 'X':
+		p.fmt.fmtFloat(v, size, verb, -1)
+	case 'f', 'e', 'E':
+		p.fmt.fmtFloat(v, size, verb, 6)
+	case 'F':
+		p.fmt.fmtFloat(v, size, 'f', 6)
+	default:
+		p.badVerb(verb)
+	}
+}
+
+// fmtComplex formats a complex number v with
+// r = real(v) and j = imag(v) as (r+ji) using
+// fmtFloat for r and j formatting.
+func (p *pp) fmtComplex(v complex128, size int, verb rune) {
+	// Make sure any unsupported verbs are found before the
+	// calls to fmtFloat to not generate an incorrect error string.
+	switch verb {
+	case 'v', 'b', 'g', 'G', 'x', 'X', 'f', 'F', 'e', 'E':
+		oldPlus := p.fmt.plus
+		p.buf.writeByte('(')
+		p.fmtFloat(real(v), size/2, verb)
+		// Imaginary part always has a sign.
+		p.fmt.plus = true
+		p.fmtFloat(imag(v), size/2, verb)
+		p.buf.writeString("i)")
+		p.fmt.plus = oldPlus
+	default:
+		p.badVerb(verb)
+	}
+}
+
+func (p *pp) fmtString(v string, verb rune) {
+	switch verb {
+	case 'v':
+		if p.fmt.sharpV {
+			p.fmt.fmtQ(v)
+		} else {
+			p.fmt.fmtS(v)
+		}
+	case 's':
+		p.fmt.fmtS(v)
+	case 'x':
+		p.fmt.fmtSx(v, ldigits)
+	case 'X':
+		p.fmt.fmtSx(v, udigits)
+	case 'q':
+		p.fmt.fmtQ(v)
+	default:
+		p.badVerb(verb)
+	}
+}
+
+func (p *pp) fmtBytes(v []byte, verb rune, typeString string) {
+	switch verb {
+	case 'v', 'd':
+		if p.fmt.sharpV {
+			p.buf.writeString(typeString)
+			if v == nil {
+				p.buf.writeString(nilParenString)
+				return
+			}
+			p.buf.writeByte('{')
+			for i, c := range v {
+				if i > 0 {
+					p.buf.writeString(commaSpaceString)
+				}
+				p.fmt0x64(uint64(c), true)
+			}
+			p.buf.writeByte('}')
+		} else {
+			p.buf.writeByte('[')
+			for i, c := range v {
+				if i > 0 {
+					p.buf.writeByte(' ')
+				}
+				p.fmt.fmtInteger(uint64(c), 10, unsigned, verb, ldigits)
+			}
+			p.buf.writeByte(']')
+		}
+	case 's':
+		p.fmt.fmtBs(v)
+	case 'x':
+		p.fmt.fmtBx(v, ldigits)
+	case 'X':
+		p.fmt.fmtBx(v, udigits)
+	case 'q':
+		p.fmt.fmtQ(string(v))
+	default:
+		p.printValue(reflect.ValueOf(v), verb, 0)
+	}
+}
+
+func (p *pp) fmtPointer(value reflect.Value, verb rune) {
+	var u uintptr
+	switch value.Kind() {
+	case reflect.Chan, reflect.Func, reflect.Map, reflect.Pointer, reflect.Slice, reflect.UnsafePointer:
+		u = value.Pointer()
+	default:
+		p.badVerb(verb)
+		return
+	}
+
+	switch verb {
+	case 'v':
+		if p.fmt.sharpV {
+			p.buf.writeByte('(')
+			p.buf.writeString(value.Type().String())
+			p.buf.writeString(")(")
+			if u == 0 {
+				p.buf.writeString(nilString)
+			} else {
+				p.fmt0x64(uint64(u), true)
+			}
+			p.buf.writeByte(')')
+		} else {
+			if u == 0 {
+				p.fmt.padString(nilAngleString)
+			} else {
+				p.fmt0x64(uint64(u), !p.fmt.sharp)
+			}
+		}
+	case 'p':
+		p.fmt0x64(uint64(u), !p.fmt.sharp)
+	case 'b', 'o', 'd', 'x', 'X':
+		p.fmtInteger(uint64(u), unsigned, verb)
+	default:
+		p.badVerb(verb)
+	}
+}
+
+func (p *pp) catchPanic(arg any, verb rune, method string) {
+	if err := recover(); err != nil {
+		// If it's a nil pointer, just say "<nil>". The likeliest causes are a
+		// Stringer that fails to guard against nil or a nil pointer for a
+		// value receiver, and in either case, "<nil>" is a nice result.
+		if v := reflect.ValueOf(arg); v.Kind() == reflect.Pointer && v.IsNil() {
+			p.buf.writeString(nilAngleString)
+			return
+		}
+		// Otherwise print a concise panic message. Most of the time the panic
+		// value will print itself nicely.
+		if p.panicking {
+			// Nested panics; the recursion in printArg cannot succeed.
+			panic(err)
+		}
+
+		oldFlags := p.fmt.fmtFlags
+		// For this output we want default behavior.
+		p.fmt.clearflags()
+
+		p.buf.writeString(percentBangString)
+		p.buf.writeRune(verb)
+		p.buf.writeString(panicString)
+		p.buf.writeString(method)
+		p.buf.writeString(" method: ")
+		p.panicking = true
+		p.printArg(err, 'v')
+		p.panicking = false
+		p.buf.writeByte(')')
+
+		p.fmt.fmtFlags = oldFlags
+	}
+}
+
+func (p *pp) handleMethods(verb rune) (handled bool) {
+	if p.erroring {
+		return
+	}
+	if verb == 'w' {
+		// It is invalid to use %w other than with Errorf or with a non-error arg.
+		_, ok := p.arg.(error)
+		if !ok || !p.wrapErrs {
+			p.badVerb(verb)
+			return true
+		}
+		// If the arg is a Formatter, pass 'v' as the verb to it.
+		verb = 'v'
+	}
+
+	// Is it a Formatter?
+	if formatter, ok := p.arg.(Formatter); ok {
+		handled = true
+		defer p.catchPanic(p.arg, verb, "Format")
+		formatter.Format(p, verb)
+		return
+	}
+
+	// If we're doing Go syntax and the argument knows how to supply it, take care of it now.
+	if p.fmt.sharpV {
+		if stringer, ok := p.arg.(GoStringer); ok {
+			handled = true
+			defer p.catchPanic(p.arg, verb, "GoString")
+			// Print the result of GoString unadorned.
+			p.fmt.fmtS(stringer.GoString())
+			return
+		}
+	} else {
+		// If a string is acceptable according to the format, see if
+		// the value satisfies one of the string-valued interfaces.
+		// Println etc. set verb to %v, which is "stringable".
+		switch verb {
+		case 'v', 's', 'x', 'X', 'q':
+			// Is it an error or Stringer?
+			// The duplication in the bodies is necessary:
+			// setting handled and deferring catchPanic
+			// must happen before calling the method.
+			switch v := p.arg.(type) {
+			case error:
+				handled = true
+				defer p.catchPanic(p.arg, verb, "Error")
+				p.fmtString(v.Error(), verb)
+				return
+
+			case Stringer:
+				handled = true
+				defer p.catchPanic(p.arg, verb, "String")
+				p.fmtString(v.String(), verb)
+				return
+			}
+		}
+	}
+	return false
+}
+
+func (p *pp) printArg(arg any, verb rune) {
+	p.arg = arg
+	p.value = reflect.Value{}
+
+	if arg == nil {
+		switch verb {
+		case 'T', 'v':
+			p.fmt.padString(nilAngleString)
+		default:
+			p.badVerb(verb)
+		}
+		return
+	}
+
+	// Special processing considerations.
+	// %T (the value's type) and %p (its address) are special; we always do them first.
+	switch verb {
+	case 'T':
+		p.fmt.fmtS(reflect.TypeOf(arg).String())
+		return
+	case 'p':
+		p.fmtPointer(reflect.ValueOf(arg), 'p')
+		return
+	}
+
+	// Some types can be done without reflection.
+	switch f := arg.(type) {
+	case bool:
+		p.fmtBool(f, verb)
+	case float32:
+		p.fmtFloat(float64(f), 32, verb)
+	case float64:
+		p.fmtFloat(f, 64, verb)
+	case complex64:
+		p.fmtComplex(complex128(f), 64, verb)
+	case complex128:
+		p.fmtComplex(f, 128, verb)
+	case int:
+		p.fmtInteger(uint64(f), signed, verb)
+	case int8:
+		p.fmtInteger(uint64(f), signed, verb)
+	case int16:
+		p.fmtInteger(uint64(f), signed, verb)
+	case int32:
+		p.fmtInteger(uint64(f), signed, verb)
+	case int64:
+		p.fmtInteger(uint64(f), signed, verb)
+	case uint:
+		p.fmtInteger(uint64(f), unsigned, verb)
+	case uint8:
+		p.fmtInteger(uint64(f), unsigned, verb)
+	case uint16:
+		p.fmtInteger(uint64(f), unsigned, verb)
+	case uint32:
+		p.fmtInteger(uint64(f), unsigned, verb)
+	case uint64:
+		p.fmtInteger(f, unsigned, verb)
+	case uintptr:
+		p.fmtInteger(uint64(f), unsigned, verb)
+	case string:
+		p.fmtString(f, verb)
+	case []byte:
+		p.fmtBytes(f, verb, "[]byte")
+	case reflect.Value:
+		// Handle extractable values with special methods
+		// since printValue does not handle them at depth 0.
+		if f.IsValid() && f.CanInterface() {
+			p.arg = f.Interface()
+			if p.handleMethods(verb) {
+				return
+			}
+		}
+		p.printValue(f, verb, 0)
+	default:
+		// If the type is not simple, it might have methods.
+		if !p.handleMethods(verb) {
+			// Need to use reflection, since the type had no
+			// interface methods that could be used for formatting.
+			p.printValue(reflect.ValueOf(f), verb, 0)
+		}
+	}
+}
+
+// printValue is similar to printArg but starts with a reflect value, not an interface{} value.
+// It does not handle 'p' and 'T' verbs because these should have been already handled by printArg.
+func (p *pp) printValue(value reflect.Value, verb rune, depth int) {
+	// Handle values with special methods if not already handled by printArg (depth == 0).
+	if depth > 0 && value.IsValid() && value.CanInterface() {
+		p.arg = value.Interface()
+		if p.handleMethods(verb) {
+			return
+		}
+	}
+	p.arg = nil
+	p.value = value
+
+	switch f := value; value.Kind() {
+	case reflect.Invalid:
+		if depth == 0 {
+			p.buf.writeString(invReflectString)
+		} else {
+			switch verb {
+			case 'v':
+				p.buf.writeString(nilAngleString)
+			default:
+				p.badVerb(verb)
+			}
+		}
+	case reflect.Bool:
+		p.fmtBool(f.Bool(), verb)
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		p.fmtInteger(uint64(f.Int()), signed, verb)
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		p.fmtInteger(f.Uint(), unsigned, verb)
+	case reflect.Float32:
+		p.fmtFloat(f.Float(), 32, verb)
+	case reflect.Float64:
+		p.fmtFloat(f.Float(), 64, verb)
+	case reflect.Complex64:
+		p.fmtComplex(f.Complex(), 64, verb)
+	case reflect.Complex128:
+		p.fmtComplex(f.Complex(), 128, verb)
+	case reflect.String:
+		p.fmtString(f.String(), verb)
+	case reflect.Map:
+		if p.fmt.sharpV {
+			p.buf.writeString(f.Type().String())
+			if f.IsNil() {
+				p.buf.writeString(nilParenString)
+				return
+			}
+			p.buf.writeByte('{')
+		} else {
+			p.buf.writeString(mapString)
+		}
+		sorted := fmtsort.Sort(f)
+		for i, key := range sorted.Key {
+			if i > 0 {
+				if p.fmt.sharpV {
+					p.buf.writeString(commaSpaceString)
+				} else {
+					p.buf.writeByte(' ')
+				}
+			}
+			p.printValue(key, verb, depth+1)
+			p.buf.writeByte(':')
+			p.printValue(sorted.Value[i], verb, depth+1)
+		}
+		if p.fmt.sharpV {
+			p.buf.writeByte('}')
+		} else {
+			p.buf.writeByte(']')
+		}
+	case reflect.Struct:
+		if p.fmt.sharpV {
+			p.buf.writeString(f.Type().String())
+		}
+		p.buf.writeByte('{')
+		for i := 0; i < f.NumField(); i++ {
+			if i > 0 {
+				if p.fmt.sharpV {
+					p.buf.writeString(commaSpaceString)
+				} else {
+					p.buf.writeByte(' ')
+				}
+			}
+			if p.fmt.plusV || p.fmt.sharpV {
+				if name := f.Type().Field(i).Name; name != "" {
+					p.buf.writeString(name)
+					p.buf.writeByte(':')
+				}
+			}
+			p.printValue(getField(f, i), verb, depth+1)
+		}
+		p.buf.writeByte('}')
+	case reflect.Interface:
+		value := f.Elem()
+		if !value.IsValid() {
+			if p.fmt.sharpV {
+				p.buf.writeString(f.Type().String())
+				p.buf.writeString(nilParenString)
+			} else {
+				p.buf.writeString(nilAngleString)
+			}
+		} else {
+			p.printValue(value, verb, depth+1)
+		}
+	case reflect.Array, reflect.Slice:
+		switch verb {
+		case 's', 'q', 'x', 'X':
+			// Handle byte and uint8 slices and arrays special for the above verbs.
+			t := f.Type()
+			if t.Elem().Kind() == reflect.Uint8 {
+				var bytes []byte
+				if f.Kind() == reflect.Slice {
+					bytes = f.Bytes()
+				} else if f.CanAddr() {
+					bytes = f.Slice(0, f.Len()).Bytes()
+				} else {
+					// We have an array, but we cannot Slice() a non-addressable array,
+					// so we build a slice by hand. This is a rare case but it would be nice
+					// if reflection could help a little more.
+					bytes = make([]byte, f.Len())
+					for i := range bytes {
+						bytes[i] = byte(f.Index(i).Uint())
+					}
+				}
+				p.fmtBytes(bytes, verb, t.String())
+				return
+			}
+		}
+		if p.fmt.sharpV {
+			p.buf.writeString(f.Type().String())
+			if f.Kind() == reflect.Slice && f.IsNil() {
+				p.buf.writeString(nilParenString)
+				return
+			}
+			p.buf.writeByte('{')
+			for i := 0; i < f.Len(); i++ {
+				if i > 0 {
+					p.buf.writeString(commaSpaceString)
+				}
+				p.printValue(f.Index(i), verb, depth+1)
+			}
+			p.buf.writeByte('}')
+		} else {
+			p.buf.writeByte('[')
+			for i := 0; i < f.Len(); i++ {
+				if i > 0 {
+					p.buf.writeByte(' ')
+				}
+				p.printValue(f.Index(i), verb, depth+1)
+			}
+			p.buf.writeByte(']')
+		}
+	case reflect.Pointer:
+		// pointer to array or slice or struct? ok at top level
+		// but not embedded (avoid loops)
+		if depth == 0 && f.Pointer() != 0 {
+			switch a := f.Elem(); a.Kind() {
+			case reflect.Array, reflect.Slice, reflect.Struct, reflect.Map:
+				p.buf.writeByte('&')
+				p.printValue(a, verb, depth+1)
+				return
+			}
+		}
+		fallthrough
+	case reflect.Chan, reflect.Func, reflect.UnsafePointer:
+		p.fmtPointer(f, verb)
+	default:
+		p.unknownType(f)
+	}
+}
+
+// intFromArg gets the argNumth element of a. On return, isInt reports whether the argument has integer type.
+func intFromArg(a []any, argNum int) (num int, isInt bool, newArgNum int) {
+	newArgNum = argNum
+	if argNum < len(a) {
+		num, isInt = a[argNum].(int) // Almost always OK.
+		if !isInt {
+			// Work harder.
+			switch v := reflect.ValueOf(a[argNum]); v.Kind() {
+			case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+				n := v.Int()
+				if int64(int(n)) == n {
+					num = int(n)
+					isInt = true
+				}
+			case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+				n := v.Uint()
+				if int64(n) >= 0 && uint64(int(n)) == n {
+					num = int(n)
+					isInt = true
+				}
+			default:
+				// Already 0, false.
+			}
+		}
+		newArgNum = argNum + 1
+		if tooLarge(num) {
+			num = 0
+			isInt = false
+		}
+	}
+	return
+}
+
+// parseArgNumber returns the value of the bracketed number, minus 1
+// (explicit argument numbers are one-indexed but we want zero-indexed).
+// The opening bracket is known to be present at format[0].
+// The returned values are the index, the number of bytes to consume
+// up to the closing paren, if present, and whether the number parsed
+// ok. The bytes to consume will be 1 if no closing paren is present.
+func parseArgNumber(format string) (index int, wid int, ok bool) {
+	// There must be at least 3 bytes: [n].
+	if len(format) < 3 {
+		return 0, 1, false
+	}
+
+	// Find closing bracket.
+	for i := 1; i < len(format); i++ {
+		if format[i] == ']' {
+			width, ok, newi := parsenum(format, 1, i)
+			if !ok || newi != i {
+				return 0, i + 1, false
+			}
+			return width - 1, i + 1, true // arg numbers are one-indexed and skip paren.
+		}
+	}
+	return 0, 1, false
+}
+
+// argNumber returns the next argument to evaluate, which is either the value of the passed-in
+// argNum or the value of the bracketed integer that begins format[i:]. It also returns
+// the new value of i, that is, the index of the next byte of the format to process.
+func (p *pp) argNumber(argNum int, format string, i int, numArgs int) (newArgNum, newi int, found bool) {
+	if len(format) <= i || format[i] != '[' {
+		return argNum, i, false
+	}
+	p.reordered = true
+	index, wid, ok := parseArgNumber(format[i:])
+	if ok && 0 <= index && index < numArgs {
+		return index, i + wid, true
+	}
+	p.goodArgNum = false
+	return argNum, i + wid, ok
+}
+
+func (p *pp) badArgNum(verb rune) {
+	p.buf.writeString(percentBangString)
+	p.buf.writeRune(verb)
+	p.buf.writeString(badIndexString)
+}
+
+func (p *pp) missingArg(verb rune) {
+	p.buf.writeString(percentBangString)
+	p.buf.writeRune(verb)
+	p.buf.writeString(missingString)
+}
+
+func (p *pp) doPrintf(format string, a []any) {
+	end := len(format)
+	argNum := 0         // we process one argument per non-trivial format
+	afterIndex := false // previous item in format was an index like [3].
+	p.reordered = false
+formatLoop:
+	for i := 0; i < end; {
+		p.goodArgNum = true
+		lasti := i
+		for i < end && format[i] != '%' {
+			i++
+		}
+		if i > lasti {
+			p.buf.writeString(format[lasti:i])
+		}
+		if i >= end {
+			// done processing format string
+			break
+		}
+
+		// Process one verb
+		i++
+
+		// Do we have flags?
+		p.fmt.clearflags()
+	simpleFormat:
+		for ; i < end; i++ {
+			c := format[i]
+			switch c {
+			case '#':
+				p.fmt.sharp = true
+			case '0':
+				p.fmt.zero = !p.fmt.minus // Only allow zero padding to the left.
+			case '+':
+				p.fmt.plus = true
+			case '-':
+				p.fmt.minus = true
+				p.fmt.zero = false // Do not pad with zeros to the right.
+			case ' ':
+				p.fmt.space = true
+			default:
+				// Fast path for common case of ascii lower case simple verbs
+				// without precision or width or argument indices.
+				if 'a' <= c && c <= 'z' && argNum < len(a) {
+					switch c {
+					case 'w':
+						p.wrappedErrs = append(p.wrappedErrs, argNum)
+						fallthrough
+					case 'v':
+						// Go syntax
+						p.fmt.sharpV = p.fmt.sharp
+						p.fmt.sharp = false
+						// Struct-field syntax
+						p.fmt.plusV = p.fmt.plus
+						p.fmt.plus = false
+					}
+					p.printArg(a[argNum], rune(c))
+					argNum++
+					i++
+					continue formatLoop
+				}
+				// Format is more complex than simple flags and a verb or is malformed.
+				break simpleFormat
+			}
+		}
+
+		// Do we have an explicit argument index?
+		argNum, i, afterIndex = p.argNumber(argNum, format, i, len(a))
+
+		// Do we have width?
+		if i < end && format[i] == '*' {
+			i++
+			p.fmt.wid, p.fmt.widPresent, argNum = intFromArg(a, argNum)
+
+			if !p.fmt.widPresent {
+				p.buf.writeString(badWidthString)
+			}
+
+			// We have a negative width, so take its value and ensure
+			// that the minus flag is set
+			if p.fmt.wid < 0 {
+				p.fmt.wid = -p.fmt.wid
+				p.fmt.minus = true
+				p.fmt.zero = false // Do not pad with zeros to the right.
+			}
+			afterIndex = false
+		} else {
+			p.fmt.wid, p.fmt.widPresent, i = parsenum(format, i, end)
+			if afterIndex && p.fmt.widPresent { // "%[3]2d"
+				p.goodArgNum = false
+			}
+		}
+
+		// Do we have precision?
+		if i+1 < end && format[i] == '.' {
+			i++
+			if afterIndex { // "%[3].2d"
+				p.goodArgNum = false
+			}
+			argNum, i, afterIndex = p.argNumber(argNum, format, i, len(a))
+			if i < end && format[i] == '*' {
+				i++
+				p.fmt.prec, p.fmt.precPresent, argNum = intFromArg(a, argNum)
+				// Negative precision arguments don't make sense
+				if p.fmt.prec < 0 {
+					p.fmt.prec = 0
+					p.fmt.precPresent = false
+				}
+				if !p.fmt.precPresent {
+					p.buf.writeString(badPrecString)
+				}
+				afterIndex = false
+			} else {
+				p.fmt.prec, p.fmt.precPresent, i = parsenum(format, i, end)
+				if !p.fmt.precPresent {
+					p.fmt.prec = 0
+					p.fmt.precPresent = true
+				}
+			}
+		}
+
+		if !afterIndex {
+			argNum, i, afterIndex = p.argNumber(argNum, format, i, len(a))
+		}
+
+		if i >= end {
+			p.buf.writeString(noVerbString)
+			break
+		}
+
+		verb, size := rune(format[i]), 1
+		if verb >= utf8.RuneSelf {
+			verb, size = utf8.DecodeRuneInString(format[i:])
+		}
+		i += size
+
+		switch {
+		case verb == '%': // Percent does not absorb operands and ignores f.wid and f.prec.
+			p.buf.writeByte('%')
+		case !p.goodArgNum:
+			p.badArgNum(verb)
+		case argNum >= len(a): // No argument left over to print for the current verb.
+			p.missingArg(verb)
+		case verb == 'w':
+			p.wrappedErrs = append(p.wrappedErrs, argNum)
+			fallthrough
+		case verb == 'v':
+			// Go syntax
+			p.fmt.sharpV = p.fmt.sharp
+			p.fmt.sharp = false
+			// Struct-field syntax
+			p.fmt.plusV = p.fmt.plus
+			p.fmt.plus = false
+			fallthrough
+		default:
+			p.printArg(a[argNum], verb)
+			argNum++
+		}
+	}
+
+	// Check for extra arguments unless the call accessed the arguments
+	// out of order, in which case it's too expensive to detect if they've all
+	// been used and arguably OK if they're not.
+	if !p.reordered && argNum < len(a) {
+		p.fmt.clearflags()
+		p.buf.writeString(extraString)
+		for i, arg := range a[argNum:] {
+			if i > 0 {
+				p.buf.writeString(commaSpaceString)
+			}
+			if arg == nil {
+				p.buf.writeString(nilAngleString)
+			} else {
+				p.buf.writeString(reflect.TypeOf(arg).String())
+				p.buf.writeByte('=')
+				p.printArg(arg, 'v')
+			}
+		}
+		p.buf.writeByte(')')
+	}
+}
+
+func (p *pp) doPrint(a []any) {
+	prevString := false
+	for argNum, arg := range a {
+		isString := arg != nil && reflect.TypeOf(arg).Kind() == reflect.String
+		// Add a space between two non-string arguments.
+		if argNum > 0 && !isString && !prevString {
+			p.buf.writeByte(' ')
+		}
+		p.printArg(arg, 'v')
+		prevString = isString
+	}
+}
+
+// doPrintln is like doPrint but always adds a space between arguments
+// and a newline after the last argument.
+func (p *pp) doPrintln(a []any) {
+	for argNum, arg := range a {
+		if argNum > 0 {
+			p.buf.writeByte(' ')
+		}
+		p.printArg(arg, 'v')
+	}
+	p.buf.writeByte('\n')
+}