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// 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 (
"bytes"
"io"
"os"
"reflect"
"utf8"
)
// Some constants in the form of bytes, to avoid string overhead.
// Needlessly fastidious, I suppose.
var (
commaSpaceBytes = []byte(", ")
nilAngleBytes = []byte("<nil>")
nilParenBytes = []byte("(nil)")
nilBytes = []byte("nil")
mapBytes = []byte("map[")
missingBytes = []byte("(MISSING)")
extraBytes = []byte("%!(EXTRA ")
irparenBytes = []byte("i)")
bytesBytes = []byte("[]byte{")
widthBytes = []byte("%!(BADWIDTH)")
precBytes = []byte("%!(BADPREC)")
noVerbBytes = []byte("%!(NOVERB)")
)
// 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) (ret int, err os.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 returns whether the flag c, a character, has been set.
Flag(int) bool
}
// Formatter is the interface implemented by values with a custom formatter.
// The implementation of Format may call Sprintf or Fprintf(f) etc.
// to generate its output.
type Formatter interface {
Format(f State, c int)
}
// 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 a %s or %v format 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
}
type pp struct {
n int
buf bytes.Buffer
runeBuf [utf8.UTFMax]byte
fmt fmt
}
// A cache holds a set of reusable objects.
// The buffered channel holds the currently available objects.
// If more are needed, the cache creates them by calling new.
type cache struct {
saved chan interface{}
new func() interface{}
}
func (c *cache) put(x interface{}) {
select {
case c.saved <- x:
// saved in cache
default:
// discard
}
}
func (c *cache) get() interface{} {
select {
case x := <-c.saved:
return x // reused from cache
default:
return c.new()
}
panic("not reached")
}
func newCache(f func() interface{}) *cache {
return &cache{make(chan interface{}, 100), f}
}
var ppFree = newCache(func() interface{} { return new(pp) })
// Allocate a new pp struct or grab a cached one.
func newPrinter() *pp {
p := ppFree.get().(*pp)
p.fmt.init(&p.buf)
return p
}
// Save used pp structs in ppFree; avoids an allocation per invocation.
func (p *pp) free() {
// Don't hold on to pp structs with large buffers.
if cap(p.buf.Bytes()) > 1024 {
return
}
p.buf.Reset()
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
case '#':
return p.fmt.sharp
case ' ':
return p.fmt.space
case '0':
return p.fmt.zero
}
return false
}
func (p *pp) add(c int) {
p.buf.WriteRune(c)
}
// 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 os.Error) {
return p.buf.Write(b)
}
// 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 ...interface{}) (n int, error os.Error) {
p := newPrinter()
p.doPrintf(format, a)
n64, error := p.buf.WriteTo(w)
p.free()
return int(n64), error
}
// 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 ...interface{}) (n int, errno os.Error) {
n, errno = Fprintf(os.Stdout, format, a...)
return n, errno
}
// Sprintf formats according to a format specifier and returns the resulting string.
func Sprintf(format string, a ...interface{}) string {
p := newPrinter()
p.doPrintf(format, a)
s := p.buf.String()
p.free()
return s
}
// Errorf formats according to a format specifier and returns the string
// converted to an os.ErrorString, which satisfies the os.Error interface.
func Errorf(format string, a ...interface{}) os.Error {
return os.NewError(Sprintf(format, a...))
}
// 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 ...interface{}) (n int, error os.Error) {
p := newPrinter()
p.doPrint(a, false, false)
n64, error := p.buf.WriteTo(w)
p.free()
return int(n64), error
}
// 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 ...interface{}) (n int, errno os.Error) {
n, errno = Fprint(os.Stdout, a...)
return n, errno
}
// 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 ...interface{}) string {
p := newPrinter()
p.doPrint(a, false, false)
s := p.buf.String()
p.free()
return s
}
// 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 ...interface{}) (n int, error os.Error) {
p := newPrinter()
p.doPrint(a, true, true)
n64, error := p.buf.WriteTo(w)
p.free()
return int(n64), error
}
// 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 ...interface{}) (n int, errno os.Error) {
n, errno = Fprintln(os.Stdout, a...)
return n, errno
}
// 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 ...interface{}) string {
p := newPrinter()
p.doPrint(a, true, true)
s := p.buf.String()
p.free()
return s
}
// Get the i'th arg of the struct value.
// If the arg 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 i := val; i.Kind() == reflect.Interface {
if inter := i.Interface(); inter != nil {
return reflect.ValueOf(inter)
}
}
return val
}
// Convert ASCII to integer. n is 0 (and got 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++ {
num = num*10 + int(s[newi]-'0')
isnum = true
}
return
}
func (p *pp) unknownType(v interface{}) {
if v == nil {
p.buf.Write(nilAngleBytes)
return
}
p.buf.WriteByte('?')
p.buf.WriteString(reflect.TypeOf(v).String())
p.buf.WriteByte('?')
}
func (p *pp) badVerb(verb int, val interface{}) {
p.add('%')
p.add('!')
p.add(verb)
p.add('(')
if val == nil {
p.buf.Write(nilAngleBytes)
} else {
p.buf.WriteString(reflect.TypeOf(val).String())
p.add('=')
p.printField(val, 'v', false, false, 0)
}
p.add(')')
}
func (p *pp) fmtBool(v bool, verb int, value interface{}) {
switch verb {
case 't', 'v':
p.fmt.fmt_boolean(v)
default:
p.badVerb(verb, value)
}
}
// fmtC formats a rune for the 'c' format.
func (p *pp) fmtC(c int64) {
rune := int(c) // Check for overflow.
if int64(rune) != c {
rune = utf8.RuneError
}
w := utf8.EncodeRune(p.runeBuf[0:utf8.UTFMax], rune)
p.fmt.pad(p.runeBuf[0:w])
}
func (p *pp) fmtInt64(v int64, verb int, value interface{}) {
switch verb {
case 'b':
p.fmt.integer(v, 2, signed, ldigits)
case 'c':
p.fmtC(v)
case 'd', 'v':
p.fmt.integer(v, 10, signed, ldigits)
case 'o':
p.fmt.integer(v, 8, signed, ldigits)
case 'x':
p.fmt.integer(v, 16, signed, ldigits)
case 'U':
p.fmtUnicode(v)
case 'X':
p.fmt.integer(v, 16, signed, udigits)
default:
p.badVerb(verb, value)
}
}
// 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.integer(int64(v), 16, unsigned, ldigits)
p.fmt.sharp = sharp
}
// fmtUnicode formats a uint64 in U+1234 form by
// temporarily turning on the unicode flag and tweaking the precision.
func (p *pp) fmtUnicode(v int64) {
precPresent := p.fmt.precPresent
prec := p.fmt.prec
if !precPresent {
// If prec is already set, leave it alone; otherwise 4 is minimum.
p.fmt.prec = 4
p.fmt.precPresent = true
}
p.fmt.unicode = true // turn on U+
p.fmt.integer(int64(v), 16, unsigned, udigits)
p.fmt.unicode = false
p.fmt.prec = prec
p.fmt.precPresent = precPresent
}
func (p *pp) fmtUint64(v uint64, verb int, goSyntax bool, value interface{}) {
switch verb {
case 'b':
p.fmt.integer(int64(v), 2, unsigned, ldigits)
case 'c':
p.fmtC(int64(v))
case 'd':
p.fmt.integer(int64(v), 10, unsigned, ldigits)
case 'v':
if goSyntax {
p.fmt0x64(v, true)
} else {
p.fmt.integer(int64(v), 10, unsigned, ldigits)
}
case 'o':
p.fmt.integer(int64(v), 8, unsigned, ldigits)
case 'x':
p.fmt.integer(int64(v), 16, unsigned, ldigits)
case 'X':
p.fmt.integer(int64(v), 16, unsigned, udigits)
default:
p.badVerb(verb, value)
}
}
func (p *pp) fmtFloat32(v float32, verb int, value interface{}) {
switch verb {
case 'b':
p.fmt.fmt_fb32(v)
case 'e':
p.fmt.fmt_e32(v)
case 'E':
p.fmt.fmt_E32(v)
case 'f':
p.fmt.fmt_f32(v)
case 'g', 'v':
p.fmt.fmt_g32(v)
case 'G':
p.fmt.fmt_G32(v)
default:
p.badVerb(verb, value)
}
}
func (p *pp) fmtFloat64(v float64, verb int, value interface{}) {
switch verb {
case 'b':
p.fmt.fmt_fb64(v)
case 'e':
p.fmt.fmt_e64(v)
case 'E':
p.fmt.fmt_E64(v)
case 'f':
p.fmt.fmt_f64(v)
case 'g', 'v':
p.fmt.fmt_g64(v)
case 'G':
p.fmt.fmt_G64(v)
default:
p.badVerb(verb, value)
}
}
func (p *pp) fmtComplex64(v complex64, verb int, value interface{}) {
switch verb {
case 'e', 'E', 'f', 'F', 'g', 'G':
p.fmt.fmt_c64(v, verb)
case 'v':
p.fmt.fmt_c64(v, 'g')
default:
p.badVerb(verb, value)
}
}
func (p *pp) fmtComplex128(v complex128, verb int, value interface{}) {
switch verb {
case 'e', 'E', 'f', 'F', 'g', 'G':
p.fmt.fmt_c128(v, verb)
case 'v':
p.fmt.fmt_c128(v, 'g')
default:
p.badVerb(verb, value)
}
}
func (p *pp) fmtString(v string, verb int, goSyntax bool, value interface{}) {
switch verb {
case 'v':
if goSyntax {
p.fmt.fmt_q(v)
} else {
p.fmt.fmt_s(v)
}
case 's':
p.fmt.fmt_s(v)
case 'x':
p.fmt.fmt_sx(v)
case 'X':
p.fmt.fmt_sX(v)
case 'q':
p.fmt.fmt_q(v)
default:
p.badVerb(verb, value)
}
}
func (p *pp) fmtBytes(v []byte, verb int, goSyntax bool, depth int, value interface{}) {
if verb == 'v' || verb == 'd' {
if goSyntax {
p.buf.Write(bytesBytes)
} else {
p.buf.WriteByte('[')
}
for i, c := range v {
if i > 0 {
if goSyntax {
p.buf.Write(commaSpaceBytes)
} else {
p.buf.WriteByte(' ')
}
}
p.printField(c, 'v', p.fmt.plus, goSyntax, depth+1)
}
if goSyntax {
p.buf.WriteByte('}')
} else {
p.buf.WriteByte(']')
}
return
}
s := string(v)
switch verb {
case 's':
p.fmt.fmt_s(s)
case 'x':
p.fmt.fmt_sx(s)
case 'X':
p.fmt.fmt_sX(s)
case 'q':
p.fmt.fmt_q(s)
default:
p.badVerb(verb, value)
}
}
func (p *pp) fmtPointer(field interface{}, value reflect.Value, verb int, goSyntax bool) {
var u uintptr
switch value.Kind() {
case reflect.Chan, reflect.Func, reflect.Map, reflect.Ptr, reflect.Slice, reflect.UnsafePointer:
u = value.Pointer()
default:
p.badVerb(verb, field)
return
}
if goSyntax {
p.add('(')
p.buf.WriteString(reflect.TypeOf(field).String())
p.add(')')
p.add('(')
if u == 0 {
p.buf.Write(nilBytes)
} else {
p.fmt0x64(uint64(u), true)
}
p.add(')')
} else {
p.fmt0x64(uint64(u), !p.fmt.sharp)
}
}
var (
intBits = reflect.TypeOf(0).Bits()
floatBits = reflect.TypeOf(0.0).Bits()
complexBits = reflect.TypeOf(1i).Bits()
uintptrBits = reflect.TypeOf(uintptr(0)).Bits()
)
func (p *pp) printField(field interface{}, verb int, plus, goSyntax bool, depth int) (wasString bool) {
if field == nil {
if verb == 'T' || verb == 'v' {
p.buf.Write(nilAngleBytes)
} else {
p.badVerb(verb, field)
}
return false
}
// Special processing considerations.
// %T (the value's type) and %p (its address) are special; we always do them first.
switch verb {
case 'T':
p.printField(reflect.TypeOf(field).String(), 's', false, false, 0)
return false
case 'p':
p.fmtPointer(field, reflect.ValueOf(field), verb, goSyntax)
return false
}
// Is it a Formatter?
if formatter, ok := field.(Formatter); ok {
formatter.Format(p, verb)
return false // this value is not a string
}
// Must not touch flags before Formatter looks at them.
if plus {
p.fmt.plus = false
}
// If we're doing Go syntax and the field knows how to supply it, take care of it now.
if goSyntax {
p.fmt.sharp = false
if stringer, ok := field.(GoStringer); ok {
// Print the result of GoString unadorned.
p.fmtString(stringer.GoString(), 's', false, field)
return false // this value is not a string
}
} else {
// Is it a Stringer?
if stringer, ok := field.(Stringer); ok {
p.printField(stringer.String(), verb, plus, false, depth)
return false // this value is not a string
}
}
// Some types can be done without reflection.
switch f := field.(type) {
case bool:
p.fmtBool(f, verb, field)
return false
case float32:
p.fmtFloat32(f, verb, field)
return false
case float64:
p.fmtFloat64(f, verb, field)
return false
case complex64:
p.fmtComplex64(complex64(f), verb, field)
return false
case complex128:
p.fmtComplex128(f, verb, field)
return false
case int:
p.fmtInt64(int64(f), verb, field)
return false
case int8:
p.fmtInt64(int64(f), verb, field)
return false
case int16:
p.fmtInt64(int64(f), verb, field)
return false
case int32:
p.fmtInt64(int64(f), verb, field)
return false
case int64:
p.fmtInt64(f, verb, field)
return false
case uint:
p.fmtUint64(uint64(f), verb, goSyntax, field)
return false
case uint8:
p.fmtUint64(uint64(f), verb, goSyntax, field)
return false
case uint16:
p.fmtUint64(uint64(f), verb, goSyntax, field)
return false
case uint32:
p.fmtUint64(uint64(f), verb, goSyntax, field)
return false
case uint64:
p.fmtUint64(f, verb, goSyntax, field)
return false
case uintptr:
p.fmtUint64(uint64(f), verb, goSyntax, field)
return false
case string:
p.fmtString(f, verb, goSyntax, field)
return verb == 's' || verb == 'v'
case []byte:
p.fmtBytes(f, verb, goSyntax, depth, field)
return verb == 's'
}
// Need to use reflection
value := reflect.ValueOf(field)
BigSwitch:
switch f := value; f.Kind() {
case reflect.Bool:
p.fmtBool(f.Bool(), verb, field)
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
p.fmtInt64(f.Int(), verb, field)
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
p.fmtUint64(uint64(f.Uint()), verb, goSyntax, field)
case reflect.Float32, reflect.Float64:
if f.Type().Size() == 4 {
p.fmtFloat32(float32(f.Float()), verb, field)
} else {
p.fmtFloat64(float64(f.Float()), verb, field)
}
case reflect.Complex64, reflect.Complex128:
if f.Type().Size() == 8 {
p.fmtComplex64(complex64(f.Complex()), verb, field)
} else {
p.fmtComplex128(complex128(f.Complex()), verb, field)
}
case reflect.String:
p.fmtString(f.String(), verb, goSyntax, field)
case reflect.Map:
if goSyntax {
p.buf.WriteString(f.Type().String())
p.buf.WriteByte('{')
} else {
p.buf.Write(mapBytes)
}
keys := f.MapKeys()
for i, key := range keys {
if i > 0 {
if goSyntax {
p.buf.Write(commaSpaceBytes)
} else {
p.buf.WriteByte(' ')
}
}
p.printField(key.Interface(), verb, plus, goSyntax, depth+1)
p.buf.WriteByte(':')
p.printField(f.MapIndex(key).Interface(), verb, plus, goSyntax, depth+1)
}
if goSyntax {
p.buf.WriteByte('}')
} else {
p.buf.WriteByte(']')
}
case reflect.Struct:
if goSyntax {
p.buf.WriteString(reflect.TypeOf(field).String())
}
p.add('{')
v := f
t := v.Type()
for i := 0; i < v.NumField(); i++ {
if i > 0 {
if goSyntax {
p.buf.Write(commaSpaceBytes)
} else {
p.buf.WriteByte(' ')
}
}
if plus || goSyntax {
if f := t.Field(i); f.Name != "" {
p.buf.WriteString(f.Name)
p.buf.WriteByte(':')
}
}
p.printField(getField(v, i).Interface(), verb, plus, goSyntax, depth+1)
}
p.buf.WriteByte('}')
case reflect.Interface:
value := f.Elem()
if !value.IsValid() {
if goSyntax {
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.Write(nilParenBytes)
} else {
p.buf.Write(nilAngleBytes)
}
} else {
return p.printField(value.Interface(), verb, plus, goSyntax, depth+1)
}
case reflect.Array, reflect.Slice:
// Byte slices are special.
if f.Type().Elem().Kind() == reflect.Uint8 {
// We know it's a slice of bytes, but we also know it does not have static type
// []byte, or it would have been caught above. Therefore we cannot convert
// it directly in the (slightly) obvious way: f.Interface().([]byte); it doesn't have
// that type, and we can't write an expression of the right type and do a
// conversion because we don't have a static way to write the right type.
// 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, goSyntax, depth, field)
return verb == 's'
}
if goSyntax {
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.WriteByte('{')
} else {
p.buf.WriteByte('[')
}
for i := 0; i < f.Len(); i++ {
if i > 0 {
if goSyntax {
p.buf.Write(commaSpaceBytes)
} else {
p.buf.WriteByte(' ')
}
}
p.printField(f.Index(i).Interface(), verb, plus, goSyntax, depth+1)
}
if goSyntax {
p.buf.WriteByte('}')
} else {
p.buf.WriteByte(']')
}
case reflect.Ptr:
v := f.Pointer()
// pointer to array or slice or struct? ok at top level
// but not embedded (avoid loops)
if v != 0 && depth == 0 {
switch a := f.Elem(); a.Kind() {
case reflect.Array, reflect.Slice:
p.buf.WriteByte('&')
p.printField(a.Interface(), verb, plus, goSyntax, depth+1)
break BigSwitch
case reflect.Struct:
p.buf.WriteByte('&')
p.printField(a.Interface(), verb, plus, goSyntax, depth+1)
break BigSwitch
}
}
if goSyntax {
p.buf.WriteByte('(')
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.WriteByte(')')
p.buf.WriteByte('(')
if v == 0 {
p.buf.Write(nilBytes)
} else {
p.fmt0x64(uint64(v), true)
}
p.buf.WriteByte(')')
break
}
if v == 0 {
p.buf.Write(nilAngleBytes)
break
}
p.fmt0x64(uint64(v), true)
case reflect.Chan, reflect.Func, reflect.UnsafePointer:
p.fmtPointer(field, value, verb, goSyntax)
default:
p.unknownType(f)
}
return false
}
// intFromArg gets the fieldnumth element of a. On return, isInt reports whether the argument has type int.
func intFromArg(a []interface{}, end, i, fieldnum int) (num int, isInt bool, newi, newfieldnum int) {
newi, newfieldnum = end, fieldnum
if i < end && fieldnum < len(a) {
num, isInt = a[fieldnum].(int)
newi, newfieldnum = i+1, fieldnum+1
}
return
}
func (p *pp) doPrintf(format string, a []interface{}) {
end := len(format)
fieldnum := 0 // we process one field per non-trivial format
for i := 0; i < end; {
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++
// flags and widths
p.fmt.clearflags()
F:
for ; i < end; i++ {
switch format[i] {
case '#':
p.fmt.sharp = true
case '0':
p.fmt.zero = true
case '+':
p.fmt.plus = true
case '-':
p.fmt.minus = true
case ' ':
p.fmt.space = true
default:
break F
}
}
// do we have width?
if i < end && format[i] == '*' {
p.fmt.wid, p.fmt.widPresent, i, fieldnum = intFromArg(a, end, i, fieldnum)
if !p.fmt.widPresent {
p.buf.Write(widthBytes)
}
} else {
p.fmt.wid, p.fmt.widPresent, i = parsenum(format, i, end)
}
// do we have precision?
if i < end && format[i] == '.' {
if format[i+1] == '*' {
p.fmt.prec, p.fmt.precPresent, i, fieldnum = intFromArg(a, end, i+1, fieldnum)
if !p.fmt.precPresent {
p.buf.Write(precBytes)
}
} else {
p.fmt.prec, p.fmt.precPresent, i = parsenum(format, i+1, end)
}
}
if i >= end {
p.buf.Write(noVerbBytes)
continue
}
c, w := utf8.DecodeRuneInString(format[i:])
i += w
// percent is special - absorbs no operand
if c == '%' {
p.buf.WriteByte('%') // We ignore width and prec.
continue
}
if fieldnum >= len(a) { // out of operands
p.buf.WriteByte('%')
p.add(c)
p.buf.Write(missingBytes)
continue
}
field := a[fieldnum]
fieldnum++
goSyntax := c == 'v' && p.fmt.sharp
plus := c == 'v' && p.fmt.plus
p.printField(field, c, plus, goSyntax, 0)
}
if fieldnum < len(a) {
p.buf.Write(extraBytes)
for ; fieldnum < len(a); fieldnum++ {
field := a[fieldnum]
if field != nil {
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.WriteByte('=')
}
p.printField(field, 'v', false, false, 0)
if fieldnum+1 < len(a) {
p.buf.Write(commaSpaceBytes)
}
}
p.buf.WriteByte(')')
}
}
func (p *pp) doPrint(a []interface{}, addspace, addnewline bool) {
prevString := false
for fieldnum := 0; fieldnum < len(a); fieldnum++ {
p.fmt.clearflags()
// always add spaces if we're doing println
field := a[fieldnum]
if fieldnum > 0 {
isString := field != nil && reflect.TypeOf(field).Kind() == reflect.String
if addspace || !isString && !prevString {
p.buf.WriteByte(' ')
}
}
prevString = p.printField(field, 'v', false, false, 0)
}
if addnewline {
p.buf.WriteByte('\n')
}
}