fmt: fix bug printing large zero-padded hexadecimal
We forgot to include the width of "0x" when computing the crossover
from internal buffer to allocated buffer.
Also add a helper function to the test for formatting large zero-padded
test strings.
Fixes #6777.
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/50820043
diff --git a/src/pkg/fmt/format.go b/src/pkg/fmt/format.go
index a54f12e..3835aa9 100644
--- a/src/pkg/fmt/format.go
+++ b/src/pkg/fmt/format.go
@@ -10,7 +10,9 @@
)
const (
- nByte = 65 // %b of an int64, plus a sign.
+ // %b of an int64, plus a sign.
+ // Hex can add 0x and we handle it specially.
+ nByte = 65
ldigits = "0123456789abcdef"
udigits = "0123456789ABCDEF"
@@ -160,9 +162,16 @@
}
var buf []byte = f.intbuf[0:]
- if f.widPresent && f.wid > nByte {
- // We're going to need a bigger boat.
- buf = make([]byte, f.wid)
+ if f.widPresent {
+ width := f.wid
+ if base == 16 && f.sharp {
+ // Also adds "0x".
+ width += 2
+ }
+ if width > nByte {
+ // We're going to need a bigger boat.
+ buf = make([]byte, width)
+ }
}
negative := signedness == signed && a < 0
