This fixes the unwanted behaviour where printing a zero float with the
#v fmt verb outputs "0" - e.g. missing the trailing decimal. This means
that the output would be interpreted as an int rather than a float when
parsed as Go source. After this change the the output is "0.0".
Fixes#26363
Change-Id: Ic5c060522459cd5ce077675d47c848b22ddc34fa
GitHub-Last-Rev: adfb061363
GitHub-Pull-Request: golang/go#26383
Reviewed-on: https://go-review.googlesource.com/123956
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Added an alternate form of printing floats and complex values
by specifying the sharp flag.
Output formatted using the the verbs v, e, E, f, F, g and G in
combination with the sharp flag will always include a decimal point.
The alternate form specified by the sharp flag for %g and %G verbs
will not truncate trailing zeros and assume a default precision of 6.
Fixes#18857.
Change-Id: I4d776239e06d7a6a90f2d8556240a359888cb7c3
Reviewed-on: https://go-review.googlesource.com/37051
Reviewed-by: Rob Pike <r@golang.org>
Ignore the f.zero flag and use spaces for padding instead
when precision is set.
Fixes#15331
Change-Id: I3ac485df24b7bdf4fddf69e3cc17c213c737b5ff
Reviewed-on: https://go-review.googlesource.com/22131
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Simplify the handling of zero padding in fmt_integer and
fmt_float to not require any adjustment of the format flags.
Note that f.zero can only be true when padding to the left
and f.wid is always greater than or equal to 0.
Change-Id: I204b57d103c0eac13d86995992f2b26209196925
Reviewed-on: https://go-review.googlesource.com/21185
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Deduplicate the verb switch for signed and unsigned integer formatting.
Make names of integer related functions consistent
with names of other fmt functions.
Consolidate basic integer tests.
Change-Id: I0c19c24f1c2c06a3b1a4d7d377dcdac3b36bb0f5
Reviewed-on: https://go-review.googlesource.com/20831
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Changes the integer function to restore the original f.zero value
and therefore padding type before returning.
Change-Id: I456449259a3d39bd6d62e110553120c31ec63f23
Reviewed-on: https://go-review.googlesource.com/20512
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Separate unicode formatting into its own fmt_unicode function.
Remove the fmtUnicode wrapper and the f.unicode and f.uniQuote
flags that are not needed anymore. Remove mangling and restoring
of the precision and sharp flags.
Removes the buffer copy needed for %#U by moving
the character encoding before the number encoding.
Changes the behavior of plus and space flag to have
no effect instead of printing a plus or space before "U+".
Always print at least four digits after "U+"
even if precision is set to less than 4.
Change-Id: If9a0ee79e9eca2c76f06a4e0fdd75d98393899ac
Reviewed-on: https://go-review.googlesource.com/20574
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Use The fmt internal buffer for character formatting instead of
the pp Printer rune decoding buffer.
Uses an uint64 instead of int64 argument to fmt_c and fmt_qc for easier
range checks since no valid runes are represented by negative numbers or
are above 0x10ffff.
Add range checks to fmt_c and fmt_qc to guarantee that a RuneError
character is returned by the functions for any invalid code point
in range uint64. For invalid code points in range utf8.MaxRune
the used utf8 and strconv functions already return a RuneError.
Change-Id: I9772f804dfcd79c3826fa7f6c5ebfbf4b5304a51
Reviewed-on: https://go-review.googlesource.com/20373
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Removes specialized functions for each verb and float/complex size
and replaces them with generic variants fmtFloat and
fmtComplex similar to other generic fmt functions.
Simplifies the complex formatting by relying on fmtFloat
to handle the verb and default precision selection.
Complex imaginary formatting does not need to clear the f.space flag
because the set f.plus flag will force a sign instead of a space.
Sets default precision for %b to -1 (same as %g and %G)
since precision for %b has no affect in strconv.AppendFloat.
Add more tests and group them a bit better.
Use local copies of +Inf,-Inf and NaN instead
of math package functions for testing.
Saves around 8kb in the go binary.
name old time/op new time/op delta
SprintfFloat-2 200ns ± 4% 196ns ± 4% -1.55% (p=0.007 n=20+20)
SprintfComplex-2 569ns ± 4% 570ns ± 3% ~ (p=0.804 n=20+20)
Change-Id: I36d35dab6f835fc2bd2c042ac97705868eb2446f
Reviewed-on: https://go-review.googlesource.com/20252
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Rob Pike <r@golang.org>
Reuse the internal buffer and use append versions of
the strconv quote functions to avoid some allocations.
Add more tests.
name old time/op new time/op delta
SprintfQuoteString-2 486ns ± 2% 416ns ± 2% -14.42% (p=0.000 n=20+20)
name old allocs/op new allocs/op delta
SprintfQuoteString-2 4.00 ± 0% 2.00 ± 0% -50.00% (p=0.000 n=20+20)
Change-Id: I63795b51fd95c53c5993ec8e6e99b659941f9f54
Reviewed-on: https://go-review.googlesource.com/20251
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
formatFloat should restore the original f.wid value before
returning. Callers should not have to save and restore f.wid.
Fixes: #14642
Change-Id: I531dae15c7997fe8909e2ad1ef7c376654afb030
Reviewed-on: https://go-review.googlesource.com/20179
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
No extra buffering is needed to save the encoding
since the left padding can be computed and written out
before the encoding is generated.
Add extra tests to both string and byte slice formatting.
name old time/op new time/op delta
SprintfHexString-2 410ns ± 3% 194ns ± 3% -52.60% (p=0.000 n=20+19)
SprintfHexBytes-2 431ns ± 3% 202ns ± 2% -53.13% (p=0.000 n=18+20)
Change-Id: Ibca4316427c89f834e4faee61614493c7eedb42b
Reviewed-on: https://go-review.googlesource.com/20097
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Count only the runes up to the requested precision
to decide where to truncate a string.
Change the loop within truncate to need fewer jumps.
name old time/op new time/op delta
SprintfTruncateString-2 188ns ± 3% 155ns ± 3% -17.43% (p=0.000 n=20+20)
Change-Id: I17ca9fc0bb8bf7648599df48e4785251bbc31e99
Reviewed-on: https://go-review.googlesource.com/20098
Reviewed-by: Rob Pike <r@golang.org>
The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.
This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:
$ perl -i -npe 's,^(\s*// .+[a-z]\.) +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.) +([A-Z])')
$ go test go/doc -update
Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Do not replace the sign in front of a number with a space if both
f.space and f.plus are both specified for number formatting.
This was already the case for integers but not for floats
and complex numbers.
Updates: #14543.
Change-Id: I07ddeb505003db84a8a7d2c743dc19fc427a00bd
Reviewed-on: https://go-review.googlesource.com/19974
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Once upon a time fmt did use bytes.Buffer for its buffer.
The buffer write methods still mimic the bytes.Buffer signatures.
The current code depends on manipulating the buffer []bytes array directly
which makes going back to bytes.Buffer by only changing the type of buffer
impossible. Since type buffer is not exported the methods can be simplified
to the needs of fmt. This saves space and avoids unnecessary overhead.
Use WriteString instead of Write for known inputs since
WriteString is faster than Write to append the same data.
This also saves space in the binary.
Remove the add method from Printer and depending on the data to be written
use WriteRune or WriteByte directly instead.
In total makes the go binary around 4 kilobyte smaller.
name old time/op new time/op delta
SprintfEmpty-2 24.1ns ± 3% 23.8ns ± 1% -1.14% (p=0.000 n=20+20)
SprintfString-2 114ns ± 2% 114ns ± 4% ~ (p=0.558 n=20+19)
SprintfInt-2 116ns ± 9% 118ns ± 7% ~ (p=0.086 n=20+20)
SprintfIntInt-2 195ns ± 6% 193ns ± 5% ~ (p=0.345 n=20+19)
SprintfPrefixedInt-2 251ns ±16% 241ns ± 9% -3.69% (p=0.024 n=20+19)
SprintfFloat-2 203ns ± 4% 205ns ± 5% ~ (p=0.153 n=20+20)
SprintfBoolean-2 101ns ± 7% 96ns ±11% -5.23% (p=0.005 n=19+20)
ManyArgs-2 651ns ± 7% 628ns ± 7% -3.44% (p=0.002 n=20+20)
FprintInt-2 164ns ± 2% 158ns ± 2% -3.62% (p=0.000 n=20+18)
FprintfBytes-2 215ns ± 1% 216ns ± 1% +0.58% (p=0.000 n=20+20)
FprintIntNoAlloc-2 115ns ± 0% 112ns ± 0% -2.61% (p=0.000 n=20+20)
ScanInts-2 700µs ± 0% 702µs ± 1% +0.38% (p=0.000 n=18+20)
ScanRecursiveInt-2 82.7ms ± 0% 82.7ms ± 0% ~ (p=0.820 n=20+20)
Change-Id: I0409eb170b8a26d9f4eb271f6292e5d39faf2d8b
Reviewed-on: https://go-review.googlesource.com/19955
Reviewed-by: Rob Pike <r@golang.org>
Move the decision if zero padding is allowed to doPrintf
where the other formatting decisions are made.
Removes some dead code for negative f.wid that was never used
due to f.wid always being positive and f.minus deciding if left
or right padding should be used.
New padding code writes directly into the buffer and is as fast
as the old version but avoids the cost of needing package init.
name old time/op new time/op delta
SprintfPadding-2 246ns ± 5% 245ns ± 4% ~ (p=0.345 n=50+47)
Change-Id: I7dfddbac8e328f4ef0cdee8fafc0d06c784b2711
Reviewed-on: https://go-review.googlesource.com/19957
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Makes zero padding of NaN and infinities consistent
by using spaces instead of zeroes to pad NaN.
Adds more tests for NaN formatting.
Fixes#14421
Change-Id: Ia20f8e878cc81ac72a744ec10d65e84b94e09c6a
Reviewed-on: https://go-review.googlesource.com/19723
Reviewed-by: Rob Pike <r@golang.org>
Remove floating point comparisons and rely only on the information
directly provided by appendFloat.
Make restoring the zero padding flag explicit instead of using a defer.
Rearrange some case distinctions to remove duplicated code.
Add more test cases for zero padded floating point numbers with sign.
benchmark old ns/op new ns/op delta
BenchmarkSprintfFloat-4 187 180 -3.74%
Change-Id: Ifa2ae85257909f40b1b18118c92b516933271729
Reviewed-on: https://go-review.googlesource.com/19721
Reviewed-by: Rob Pike <r@golang.org>
Also improve the documentation. A prior fix in this release
changed the properties for empty strings and slices, incorrectly.
Previous behavior is now restored and better documented.
Add lots of tests.
The behavior is that when using a string-like format (%s %q %x %X)
a byte slice is equivalent to a string, and printed as a unit. The padding
applies to the entire object. (The space and sharp flags apply
elementwise.)
Fixes#11422.
Fixes#10430.
Change-Id: I758f0521caf71630437e43990ec6d6c9a92655e3
Reviewed-on: https://go-review.googlesource.com/11600
Reviewed-by: Russ Cox <rsc@golang.org>
Allow room for the initial minus sign of negative integers when
computing widths.
Fixes#10945.
Change-Id: I04d80203aaff64611992725d613ec13ed2ae721f
Reviewed-on: https://go-review.googlesource.com/10393
Reviewed-by: Rob Pike <r@golang.org>
The code already handled high widths but not high precisions.
Also make sure it handles the harder cases of %U.
Fixes#10745.
Change-Id: Ib4d394d49a9941eeeaff866dc59d80483e312a98
Reviewed-on: https://go-review.googlesource.com/9769
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The documentation is clear that formats like %02x applied to a
byte slice are per-element, so the result should be nothing if the
slice is empty. It's not, because the top-level padding routine is called.
It shouldn't be: the loop does the padding for us.
Fixes#10430.
Change-Id: I04ea0e804c0f2e70fff3701e5bf22acc90e890da
Reviewed-on: https://go-review.googlesource.com/8864
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Apply a similar transformation to %+v that we did to %#v, making it
a top-level setting separate from the + flag itself. This fixes the
appearance of flags in Formatters and cleans up the code too,
probably making it a little faster.
Fixes#8835.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/154820043
The %#v verb is special: it says all values below need to print as %#v.
However, for some situations the # flag has other meanings and this
causes some issues, particularly in how Formatters work. Since %#v
dominates all formatting, translate it into actual state of the formatter
and decouple it from the # flag itself within the calculations (although
it must be restored when methods are doing the work.)
The result is cleaner code and correct handling of # for Formatters.
TODO: Apply the same thinking to the + flag in a followup CL.
Also, the wasString return value in handleMethods is always false,
so eliminate it.
Update #8835
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/146650043
Previous behavior was undocumented and inconsistent. Now it is documented
and consistent and measures the input size, since that makes more sense
when talking about %q and %x. For %s the change has no effect.
Fixes#8151.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/144540044
Dave Brophy
Darshan Parajuli
Martin Möhrmann
Brad Fitzpatrick
Martin Möhrmann
Rob Pike
Håvard Haugen
Russ Cox