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/goPublic

Commit0a164d2

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[release-branch.go1.3] fmt: fix signs when zero padding.
««« CL 103480043 / 777dd5a434dbfmt: fix signs when zero padding.Bug was introduced recently. Add more tests, fix the bugs.Suppress + sign when not required in zero padding.Do not zero pad infinities.All old tests still pass.This time for sure!Fixes#8217.LGTM=rscR=golang-codereviews, dan.kortschak, rscCC=golang-codereviewshttps://golang.org/cl/103480043»»»LGTM=r, rscR=r, rscCC=golang-codereviewshttps://golang.org/cl/110040043
1 parent9d7a83a commit0a164d2

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2 files changed

+147
-39
lines changed

2 files changed

+147
-39
lines changed

‎src/pkg/fmt/fmt_test.go‎

Lines changed: 113 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -513,9 +513,76 @@ var fmtTests = []struct {
513513
{"%0.100f",1.0,zeroFill("1.",100,"")},
514514
{"%0.100f",-1.0,zeroFill("-1.",100,"")},
515515

516-
// Zero padding floats used to put the minus sign in the middle.
517-
{"%020f",-1.0,"-000000000001.000000"},
516+
// Comparison of padding rules with C printf.
517+
/*
518+
C program:
519+
#include <stdio.h>
520+
521+
char *format[] = {
522+
"[%.2f]",
523+
"[% .2f]",
524+
"[%+.2f]",
525+
"[%7.2f]",
526+
"[% 7.2f]",
527+
"[%+7.2f]",
528+
"[%07.2f]",
529+
"[% 07.2f]",
530+
"[%+07.2f]",
531+
};
532+
533+
int main(void) {
534+
int i;
535+
for(i = 0; i < 9; i++) {
536+
printf("%s: ", format[i]);
537+
printf(format[i], 1.0);
538+
printf(" ");
539+
printf(format[i], -1.0);
540+
printf("\n");
541+
}
542+
}
543+
544+
Output:
545+
[%.2f]: [1.00] [-1.00]
546+
[% .2f]: [ 1.00] [-1.00]
547+
[%+.2f]: [+1.00] [-1.00]
548+
[%7.2f]: [ 1.00] [ -1.00]
549+
[% 7.2f]: [ 1.00] [ -1.00]
550+
[%+7.2f]: [ +1.00] [ -1.00]
551+
[%07.2f]: [0001.00] [-001.00]
552+
[% 07.2f]: [ 001.00] [-001.00]
553+
[%+07.2f]: [+001.00] [-001.00]
554+
*/
555+
{"%.2f",1.0,"1.00"},
556+
{"%.2f",-1.0,"-1.00"},
557+
{"% .2f",1.0," 1.00"},
558+
{"% .2f",-1.0,"-1.00"},
559+
{"%+.2f",1.0,"+1.00"},
560+
{"%+.2f",-1.0,"-1.00"},
561+
{"%7.2f",1.0," 1.00"},
562+
{"%7.2f",-1.0," -1.00"},
563+
{"% 7.2f",1.0," 1.00"},
564+
{"% 7.2f",-1.0," -1.00"},
565+
{"%+7.2f",1.0," +1.00"},
566+
{"%+7.2f",-1.0," -1.00"},
567+
{"%07.2f",1.0,"0001.00"},
568+
{"%07.2f",-1.0,"-001.00"},
569+
{"% 07.2f",1.0," 001.00"},
570+
{"% 07.2f",-1.0,"-001.00"},
571+
{"%+07.2f",1.0,"+001.00"},
572+
{"%+07.2f",-1.0,"-001.00"},
573+
574+
// Complex numbers: exhaustively tested in TestComplexFormatting.
575+
{"%7.2f",1+2i,"( 1.00 +2.00i)"},
576+
{"%+07.2f",-1-2i,"(-001.00-002.00i)"},
577+
// Zero padding does not apply to infinities.
578+
{"%020f",math.Inf(-1)," -Inf"},
579+
{"%020f",math.Inf(+1)," +Inf"},
580+
{"% 020f",math.Inf(-1)," -Inf"},
581+
{"% 020f",math.Inf(+1)," Inf"},
582+
{"%+020f",math.Inf(-1)," -Inf"},
583+
{"%+020f",math.Inf(+1)," +Inf"},
518584
{"%20f",-1.0," -1.000000"},
585+
// Make sure we can handle very large widths.
519586
{"%0100f",-1.0,zeroFill("-",99,"1.000000")},
520587

521588
// Complex fmt used to leave the plus flag set for future entries in the array
@@ -601,6 +668,50 @@ func TestSprintf(t *testing.T) {
601668
}
602669
}
603670

671+
// TestComplexFormatting checks that a complex always formats to the same
672+
// thing as if done by hand with two singleton prints.
673+
funcTestComplexFormatting(t*testing.T) {
674+
varyesNo= []bool{true,false}
675+
varsigns= []float64{1,0,-1}
676+
for_,plus:=rangeyesNo {
677+
for_,zero:=rangeyesNo {
678+
for_,space:=rangeyesNo {
679+
for_,char:=range"fFeEgG" {
680+
realFmt:="%"
681+
ifzero {
682+
realFmt+="0"
683+
}
684+
ifspace {
685+
realFmt+=" "
686+
}
687+
ifplus {
688+
realFmt+="+"
689+
}
690+
realFmt+="10.2"
691+
realFmt+=string(char)
692+
// Imaginary part always has a sign, so force + and ignore space.
693+
imagFmt:="%"
694+
ifzero {
695+
imagFmt+="0"
696+
}
697+
imagFmt+="+"
698+
imagFmt+="10.2"
699+
imagFmt+=string(char)
700+
for_,realSign:=rangesigns {
701+
for_,imagSign:=rangesigns {
702+
one:=Sprintf(realFmt,complex(realSign,imagSign))
703+
two:=Sprintf("("+realFmt+imagFmt+"i)",realSign,imagSign)
704+
ifone!=two {
705+
t.Error(f,one,two)
706+
}
707+
}
708+
}
709+
}
710+
}
711+
}
712+
}
713+
}
714+
604715
typeSE []interface{}// slice of empty; notational compactness.
605716

606717
varreorderTests= []struct {

‎src/pkg/fmt/format.go‎

Lines changed: 34 additions & 37 deletions
Original file line numberDiff line numberDiff line change
@@ -368,14 +368,25 @@ func (f *fmt) formatFloat(v float64, verb byte, prec, n int) {
368368
}else {
369369
num[0]='+'
370370
}
371+
// Special handling for infinity, which doesn't look like a number so shouldn't be padded with zeros.
372+
ifmath.IsInf(v,0) {
373+
iff.zero {
374+
deferfunc() {f.zero=true }()
375+
f.zero=false
376+
}
377+
}
371378
// num is now a signed version of the number.
372379
// If we're zero padding, want the sign before the leading zeros.
373380
// Achieve this by writing the sign out and then padding the unsigned number.
374381
iff.zero&&f.widPresent&&f.wid>len(num) {
375-
f.buf.WriteByte(num[0])
376-
f.wid--
382+
iff.space&&v>=0 {
383+
f.buf.WriteByte(' ')// This is what C does: even with zero, f.space means space.
384+
f.wid--
385+
}elseiff.plus||v<0 {
386+
f.buf.WriteByte(num[0])
387+
f.wid--
388+
}
377389
f.pad(num[1:])
378-
f.wid++// Restore width; complex numbers will reuse this value for imaginary part.
379390
return
380391
}
381392
// f.space says to replace a leading + with a space.
@@ -436,60 +447,46 @@ func (f *fmt) fmt_fb32(v float32) { f.formatFloat(float64(v), 'b', 0, 32) }
436447

437448
// fmt_c64 formats a complex64 according to the verb.
438449
func (f*fmt)fmt_c64(vcomplex64,verbrune) {
439-
f.buf.WriteByte('(')
440-
r:=real(v)
441-
oldPlus:=f.plus
442-
fori:=0; ;i++ {
443-
switchverb {
444-
case'b':
445-
f.fmt_fb32(r)
446-
case'e':
447-
f.fmt_e32(r)
448-
case'E':
449-
f.fmt_E32(r)
450-
case'f','F':
451-
f.fmt_f32(r)
452-
case'g':
453-
f.fmt_g32(r)
454-
case'G':
455-
f.fmt_G32(r)
456-
}
457-
ifi!=0 {
458-
break
459-
}
460-
f.plus=true
461-
r=imag(v)
462-
}
463-
f.plus=oldPlus
464-
f.buf.Write(irparenBytes)
450+
f.fmt_complex(float64(real(v)),float64(imag(v)),32,verb)
465451
}
466452

467453
// fmt_c128 formats a complex128 according to the verb.
468454
func (f*fmt)fmt_c128(vcomplex128,verbrune) {
455+
f.fmt_complex(real(v),imag(v),64,verb)
456+
}
457+
458+
// fmt_complex formats a complex number as (r+ji).
459+
func (f*fmt)fmt_complex(r,jfloat64,sizeint,verbrune) {
469460
f.buf.WriteByte('(')
470-
r:=real(v)
471461
oldPlus:=f.plus
462+
oldSpace:=f.space
463+
oldWid:=f.wid
472464
fori:=0; ;i++ {
473465
switchverb {
474466
case'b':
475-
f.fmt_fb64(r)
467+
f.formatFloat(r,'b',0,size)
476468
case'e':
477-
f.fmt_e64(r)
469+
f.formatFloat(r,'e',doPrec(f,6),size)
478470
case'E':
479-
f.fmt_E64(r)
471+
f.formatFloat(r,'E',doPrec(f,6),size)
480472
case'f','F':
481-
f.fmt_f64(r)
473+
f.formatFloat(r,'f',doPrec(f,6),size)
482474
case'g':
483-
f.fmt_g64(r)
475+
f.formatFloat(r,'g',doPrec(f,-1),size)
484476
case'G':
485-
f.fmt_G64(r)
477+
f.formatFloat(r,'G',doPrec(f,-1),size)
486478
}
487479
ifi!=0 {
488480
break
489481
}
482+
// Imaginary part always has a sign.
490483
f.plus=true
491-
r=imag(v)
484+
f.space=false
485+
f.wid=oldWid
486+
r=j
492487
}
488+
f.space=oldSpace
493489
f.plus=oldPlus
490+
f.wid=oldWid
494491
f.buf.Write(irparenBytes)
495492
}

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