mirror of
https://github.com/golang/go
synced 2024-10-05 02:21:22 -06:00
ac09eb4f49
R=rsc DELTA=25 (19 added, 0 deleted, 6 changed) OCL=20985 CL=20985
622 lines
14 KiB
Go
622 lines
14 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package fmt
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/*
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C-like printf, but because of reflection knowledge does not need
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to be told about sizes and signedness (no %llud etc. - just %d).
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*/
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import (
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"fmt";
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"io";
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"reflect";
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"os";
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)
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// Representation of printer state passed to custom formatters.
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// Provides access to the io.Write interface plus information about
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// the active formatting verb.
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export type Formatter interface {
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Write(b *[]byte) (ret int, err *os.Error);
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Width() (wid int, ok bool);
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Precision() (prec int, ok bool);
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}
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type Format interface {
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Format(f Formatter, c int);
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}
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type String interface {
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String() string
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}
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const Runeself = 0x80
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const AllocSize = 32
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type P struct {
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n int;
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buf *[]byte;
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fmt *Fmt;
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wid int;
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wid_ok bool;
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prec int;
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prec_ok bool;
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}
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func Printer() *P {
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p := new(P);
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p.fmt = fmt.New();
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return p;
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}
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func (p *P) Width() (wid int, ok bool) {
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return p.wid, p.wid_ok
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}
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func (p *P) Precision() (prec int, ok bool) {
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return p.prec, p.prec_ok
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}
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func (p *P) ensure(n int) {
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if p.buf == nil || len(p.buf) < n {
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newn := AllocSize;
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if p.buf != nil {
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newn += len(p.buf);
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}
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if newn < n {
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newn = n + AllocSize
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}
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b := new([]byte, newn);
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for i := 0; i < p.n; i++ {
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b[i] = p.buf[i];
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}
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p.buf = b;
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}
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}
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func (p *P) addstr(s string) {
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n := len(s);
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p.ensure(p.n + n);
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for i := 0; i < n; i++ {
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p.buf[p.n] = s[i];
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p.n++;
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}
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}
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func (p *P) addbytes(b *[]byte, start, end int) {
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p.ensure(p.n + end-start);
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for i := start; i < end; i++ {
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p.buf[p.n] = b[i];
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p.n++;
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}
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}
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func (p *P) add(c int) {
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p.ensure(p.n + 1);
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if c < Runeself {
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p.buf[p.n] = byte(c);
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p.n++;
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} else {
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p.addstr(string(c));
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}
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}
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// Implement Write so we can call fprintf on a P, for
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// recursive use in custom verbs.
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func (p *P) Write(b *[]byte) (ret int, err *os.Error) {
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p.addbytes(b, 0, len(b));
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return len(b), nil;
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}
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func (p *P) doprintf(format string, v reflect.StructValue);
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func (p *P) doprint(v reflect.StructValue, addspace, addnewline bool);
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// These routines end in 'f' and take a format string.
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export func fprintf(w io.Write, format string, a ...) (n int, error *os.Error) {
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v := reflect.NewValue(a).(reflect.PtrValue).Sub().(reflect.StructValue);
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p := Printer();
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p.doprintf(format, v);
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n, error = w.Write(p.buf[0:p.n]);
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return n, error;
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}
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export func printf(format string, v ...) (n int, errno *os.Error) {
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n, errno = fprintf(os.Stdout, format, v);
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return n, errno;
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}
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export func sprintf(format string, a ...) string {
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v := reflect.NewValue(a).(reflect.PtrValue).Sub().(reflect.StructValue);
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p := Printer();
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p.doprintf(format, v);
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s := string(p.buf)[0 : p.n];
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return s;
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}
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// These routines do not take a format string and add spaces only
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// when the operand on neither side is a string.
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export func fprint(w io.Write, a ...) (n int, error *os.Error) {
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v := reflect.NewValue(a).(reflect.PtrValue).Sub().(reflect.StructValue);
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p := Printer();
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p.doprint(v, false, false);
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n, error = w.Write(p.buf[0:p.n]);
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return n, error;
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}
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export func print(v ...) (n int, errno *os.Error) {
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n, errno = fprint(os.Stdout, v);
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return n, errno;
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}
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export func sprint(a ...) string {
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v := reflect.NewValue(a).(reflect.PtrValue).Sub().(reflect.StructValue);
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p := Printer();
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p.doprint(v, false, false);
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s := string(p.buf)[0 : p.n];
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return s;
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}
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// These routines end in 'ln', do not take a format string,
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// always add spaces between operands, and add a newline
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// after the last operand.
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export func fprintln(w io.Write, a ...) (n int, error *os.Error) {
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v := reflect.NewValue(a).(reflect.PtrValue).Sub().(reflect.StructValue);
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p := Printer();
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p.doprint(v, true, true);
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n, error = w.Write(p.buf[0:p.n]);
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return n, error;
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}
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export func println(v ...) (n int, errno *os.Error) {
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n, errno = fprintln(os.Stdout, v);
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return n, errno;
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}
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export func sprintln(a ...) string {
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v := reflect.NewValue(a).(reflect.PtrValue).Sub().(reflect.StructValue);
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p := Printer();
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p.doprint(v, true, true);
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s := string(p.buf)[0 : p.n];
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return s;
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}
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// Get the i'th arg of the struct value.
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// If the arg itself is an interface, return a value for
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// the thing inside the interface, not the interface itself.
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func getField(v reflect.StructValue, i int) reflect.Value {
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val := v.Field(i);
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if val.Kind() == reflect.InterfaceKind {
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inter := val.(reflect.InterfaceValue).Get();
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return reflect.NewValue(inter);
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}
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return val;
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}
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// Getters for the fields of the argument structure.
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func getBool(v reflect.Value) (val bool, ok bool) {
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switch v.Kind() {
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case reflect.BoolKind:
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return v.(reflect.BoolValue).Get(), true;
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}
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return false, false
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}
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func getInt(v reflect.Value) (val int64, signed, ok bool) {
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switch v.Kind() {
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case reflect.IntKind:
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return int64(v.(reflect.IntValue).Get()), true, true;
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case reflect.Int8Kind:
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return int64(v.(reflect.Int8Value).Get()), true, true;
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case reflect.Int16Kind:
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return int64(v.(reflect.Int16Value).Get()), true, true;
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case reflect.Int32Kind:
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return int64(v.(reflect.Int32Value).Get()), true, true;
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case reflect.Int64Kind:
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return int64(v.(reflect.Int64Value).Get()), true, true;
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case reflect.UintKind:
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return int64(v.(reflect.UintValue).Get()), false, true;
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case reflect.Uint8Kind:
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return int64(v.(reflect.Uint8Value).Get()), false, true;
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case reflect.Uint16Kind:
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return int64(v.(reflect.Uint16Value).Get()), false, true;
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case reflect.Uint32Kind:
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return int64(v.(reflect.Uint32Value).Get()), false, true;
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case reflect.Uint64Kind:
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return int64(v.(reflect.Uint64Value).Get()), false, true;
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}
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return 0, false, false;
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}
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func getString(v reflect.Value) (val string, ok bool) {
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switch v.Kind() {
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case reflect.StringKind:
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return v.(reflect.StringValue).Get(), true;
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}
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if valb, okb := v.Interface().(*[]byte); okb {
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return string(valb), true;
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}
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return "", false;
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}
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func getFloat32(v reflect.Value) (val float32, ok bool) {
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switch v.Kind() {
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case reflect.Float32Kind:
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return float32(v.(reflect.Float32Value).Get()), true;
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case reflect.FloatKind:
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if v.Type().Size()*8 == 32 {
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return float32(v.(reflect.FloatValue).Get()), true;
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}
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}
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return 0.0, false;
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}
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func getFloat64(v reflect.Value) (val float64, ok bool) {
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switch v.Kind() {
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case reflect.FloatKind:
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if v.Type().Size()*8 == 64 {
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return float64(v.(reflect.FloatValue).Get()), true;
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}
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case reflect.Float64Kind:
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return float64(v.(reflect.Float64Value).Get()), true;
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case reflect.Float80Kind:
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break; // TODO: what to do here?
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}
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return 0.0, false;
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}
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func getPtr(v reflect.Value) (val uintptr, ok bool) {
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switch v.Kind() {
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case reflect.PtrKind:
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return uintptr(v.(reflect.PtrValue).Get()), true;
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}
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return 0, false;
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}
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func getArrayPtr(v reflect.Value) (val reflect.ArrayValue, ok bool) {
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if v.Kind() == reflect.PtrKind {
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v = v.(reflect.PtrValue).Sub();
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if v.Kind() == reflect.ArrayKind {
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return v.(reflect.ArrayValue), true;
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}
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}
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return nil, false;
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}
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// Convert ASCII to integer. n is 0 (and got is false) if no number present.
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func parsenum(s string, start, end int) (n int, got bool, newi int) {
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if start >= end {
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return 0, false, end
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}
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isnum := false;
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num := 0;
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for '0' <= s[start] && s[start] <= '9' {
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num = num*10 + int(s[start] - '0');
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start++;
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isnum = true;
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}
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return num, isnum, start;
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}
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func (p *P) printField(field reflect.Value) (was_string bool) {
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inter := field.Interface();
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if inter != nil {
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if stringer, ok := inter.(String); ok {
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p.addstr(stringer.String());
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return false; // this value is not a string
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}
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}
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s := "";
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switch field.Kind() {
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case reflect.BoolKind:
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s = p.fmt.boolean(field.(reflect.BoolValue).Get()).str();
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case reflect.IntKind, reflect.Int8Kind, reflect.Int16Kind, reflect.Int32Kind, reflect.Int64Kind:
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v, signed, ok := getInt(field);
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s = p.fmt.d64(v).str();
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case reflect.UintKind, reflect.Uint8Kind, reflect.Uint16Kind, reflect.Uint32Kind, reflect.Uint64Kind:
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v, signed, ok := getInt(field);
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s = p.fmt.ud64(uint64(v)).str();
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case reflect.Float32Kind:
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v, ok := getFloat32(field);
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s = p.fmt.g32(v).str();
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case reflect.Float64Kind, reflect.Float80Kind:
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v, ok := getFloat64(field);
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s = p.fmt.g64(v).str();
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case reflect.FloatKind:
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if field.Type().Size()*8 == 32 {
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v, ok := getFloat32(field);
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s = p.fmt.g32(v).str();
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} else {
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v, ok := getFloat64(field);
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s = p.fmt.g64(v).str();
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}
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case reflect.StringKind:
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v, ok := getString(field);
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s = p.fmt.s(v).str();
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was_string = true;
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case reflect.PtrKind:
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if v, ok := getPtr(field); v == 0 {
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s = "<nil>"
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} else {
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// pointer to array?
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if a, ok := getArrayPtr(field); ok {
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p.addstr("&[");
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for i := 0; i < a.Len(); i++ {
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if i > 0 {
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p.addstr(" ");
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}
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p.printField(a.Elem(i));
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}
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p.addstr("]");
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} else {
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p.add('0');
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p.add('x');
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s = p.fmt.uX64(uint64(v)).str();
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}
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}
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case reflect.StructKind:
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p.add('{');
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p.doprint(field, true, false);
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p.add('}');
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case reflect.InterfaceKind:
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inter := field.(reflect.InterfaceValue).Get();
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if inter == nil {
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s = "<nil>"
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} else {
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// should never happen since a non-nil interface always has a type
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s = "<non-nil interface>";
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}
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default:
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s = "?" + field.Type().String() + "?";
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}
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p.addstr(s);
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return was_string;
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}
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func (p *P) doprintf(format string, v reflect.StructValue) {
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p.ensure(len(format)); // a good starting size
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end := len(format) - 1;
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fieldnum := 0; // we process one field per non-trivial format
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for i := 0; i <= end; {
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c, w := sys.stringtorune(format, i);
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if c != '%' || i == end {
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p.add(c);
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i += w;
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continue;
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}
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i++;
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// flags
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F: for ; i < end; i++ {
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switch format[i] {
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case '#':
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p.fmt.sharp = true;
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case '0':
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p.fmt.zero = true;
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case '+':
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p.fmt.plus = true;
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case '-':
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p.fmt.minus = true;
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case ' ':
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p.fmt.space = true;
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default:
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break F;
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}
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}
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// do we have 20 (width)?
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p.wid, p.wid_ok, i = parsenum(format, i, end);
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p.prec_ok = false;
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// do we have .20 (precision)?
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if i < end && format[i] == '.' {
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p.prec, p.prec_ok, i = parsenum(format, i+1, end);
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}
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c, w = sys.stringtorune(format, i);
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i += w;
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// percent is special - absorbs no operand
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if c == '%' {
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p.add('%'); // TODO: should we bother with width & prec?
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continue;
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}
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if fieldnum >= v.Len() { // out of operands
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p.add('%');
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p.add(c);
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p.addstr("(missing)");
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continue;
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}
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field := getField(v, fieldnum);
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fieldnum++;
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inter := field.Interface();
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if inter != nil && c != 'T' { // don't want thing to describe itself if we're asking for its type
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if formatter, ok := inter.(Format); ok {
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formatter.Format(p, c);
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continue;
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}
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}
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s := "";
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if p.wid_ok {
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p.fmt.w(p.wid);
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}
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if p.prec_ok {
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p.fmt.p(p.prec);
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}
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switch c {
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// bool
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case 't':
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if v, ok := getBool(field); ok {
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if v {
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s = "true";
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} else {
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s = "false";
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}
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} else {
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goto badtype;
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}
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|
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// int
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case 'b':
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if v, signed, ok := getInt(field); ok {
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s = p.fmt.b64(uint64(v)).str() // always unsigned
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} else if v, ok := getFloat32(field); ok {
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s = p.fmt.fb32(v).str()
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} else if v, ok := getFloat64(field); ok {
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s = p.fmt.fb64(v).str()
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} else {
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goto badtype
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}
|
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case 'c':
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if v, signed, ok := getInt(field); ok {
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s = p.fmt.c(int(v)).str()
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} else {
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goto badtype
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}
|
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case 'd':
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if v, signed, ok := getInt(field); ok {
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if signed {
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s = p.fmt.d64(v).str()
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} else {
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s = p.fmt.ud64(uint64(v)).str()
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}
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} else {
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goto badtype
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}
|
|
case 'o':
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|
if v, signed, ok := getInt(field); ok {
|
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if signed {
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|
s = p.fmt.o64(v).str()
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} else {
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s = p.fmt.uo64(uint64(v)).str()
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}
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} else {
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goto badtype
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}
|
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case 'x':
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if v, signed, ok := getInt(field); ok {
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if signed {
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s = p.fmt.x64(v).str()
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} else {
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s = p.fmt.ux64(uint64(v)).str()
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}
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} else if v, ok := getString(field); ok {
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s = p.fmt.sx(v).str();
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} else {
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goto badtype
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}
|
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case 'X':
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if v, signed, ok := getInt(field); ok {
|
|
if signed {
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s = p.fmt.X64(v).str()
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|
} else {
|
|
s = p.fmt.uX64(uint64(v)).str()
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}
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} else if v, ok := getString(field); ok {
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s = p.fmt.sX(v).str();
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} else {
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goto badtype
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}
|
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|
|
// float
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|
case 'e':
|
|
if v, ok := getFloat32(field); ok {
|
|
s = p.fmt.e32(v).str()
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} else if v, ok := getFloat64(field); ok {
|
|
s = p.fmt.e64(v).str()
|
|
} else {
|
|
goto badtype
|
|
}
|
|
case 'f':
|
|
if v, ok := getFloat32(field); ok {
|
|
s = p.fmt.f32(v).str()
|
|
} else if v, ok := getFloat64(field); ok {
|
|
s = p.fmt.f64(v).str()
|
|
} else {
|
|
goto badtype
|
|
}
|
|
case 'g':
|
|
if v, ok := getFloat32(field); ok {
|
|
s = p.fmt.g32(v).str()
|
|
} else if v, ok := getFloat64(field); ok {
|
|
s = p.fmt.g64(v).str()
|
|
} else {
|
|
goto badtype
|
|
}
|
|
|
|
// string
|
|
case 's':
|
|
if v, ok := getString(field); ok {
|
|
s = p.fmt.s(v).str()
|
|
} else {
|
|
goto badtype
|
|
}
|
|
case 'q':
|
|
if v, ok := getString(field); ok {
|
|
s = p.fmt.q(v).str()
|
|
} else {
|
|
goto badtype
|
|
}
|
|
|
|
// pointer
|
|
case 'p':
|
|
if v, ok := getPtr(field); ok {
|
|
if v == 0 {
|
|
s = "<nil>"
|
|
} else {
|
|
s = "0x" + p.fmt.uX64(uint64(v)).str()
|
|
}
|
|
} else {
|
|
goto badtype
|
|
}
|
|
|
|
// arbitrary value; do your best
|
|
case 'v':
|
|
p.printField(field);
|
|
|
|
// the value's type
|
|
case 'T':
|
|
s = field.Type().String();
|
|
|
|
default:
|
|
badtype:
|
|
s = "%" + string(c) + "(" + field.Type().String() + ")%";
|
|
}
|
|
p.addstr(s);
|
|
}
|
|
if fieldnum < v.Len() {
|
|
p.addstr("?(extra ");
|
|
for ; fieldnum < v.Len(); fieldnum++ {
|
|
p.addstr(getField(v, fieldnum).Type().String());
|
|
if fieldnum + 1 < v.Len() {
|
|
p.addstr(", ");
|
|
}
|
|
}
|
|
p.addstr(")");
|
|
}
|
|
}
|
|
|
|
func (p *P) doprint(v reflect.StructValue, addspace, addnewline bool) {
|
|
prev_string := false;
|
|
for fieldnum := 0; fieldnum < v.Len(); fieldnum++ {
|
|
// always add spaces if we're doing println
|
|
field := getField(v, fieldnum);
|
|
if fieldnum > 0 {
|
|
if addspace {
|
|
p.add(' ')
|
|
} else if field.Kind() != reflect.StringKind && !prev_string{
|
|
// if not doing println, add spaces if neither side is a string
|
|
p.add(' ')
|
|
}
|
|
}
|
|
was_string := p.printField(field);
|
|
prev_string = was_string;
|
|
}
|
|
if addnewline {
|
|
p.add('\n')
|
|
}
|
|
}
|