fmt: fix panic with large precision
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>
diff --git a/src/fmt/fmt_test.go b/src/fmt/fmt_test.go
index ab3ffae..ba99cb0 100644
--- a/src/fmt/fmt_test.go
+++ b/src/fmt/fmt_test.go
@@ -557,6 +557,11 @@
{"%0.100f", 1.0, zeroFill("1.", 100, "")},
{"%0.100f", -1.0, zeroFill("-1.", 100, "")},
+ // Used to panic: integer function didn't look at f.prec or f.unicode.
+ {"%#.80x", 42, "0x0000000000000000000000000000000000000000000000000000000000000000000000000000002a"},
+ {"%.80U", 42, "U+0000000000000000000000000000000000000000000000000000000000000000000000000000002A"},
+ {"%#.80U", '日', "U+000000000000000000000000000000000000000000000000000000000000000000000000000065E5 '日'"},
+
// Comparison of padding rules with C printf.
/*
C program:
diff --git a/src/fmt/format.go b/src/fmt/format.go
index 86673ab..099f8a5 100644
--- a/src/fmt/format.go
+++ b/src/fmt/format.go
@@ -163,12 +163,20 @@
}
var buf []byte = f.intbuf[0:]
- if f.widPresent {
- width := f.wid
+ if f.widPresent || f.precPresent {
+ width := f.wid + f.prec // Only one will be set, both are positive; this provides the maximum.
if base == 16 && f.sharp {
// Also adds "0x".
width += 2
}
+ if f.unicode {
+ // Also adds "U+".
+ width += 2
+ if f.uniQuote {
+ // Also adds " 'x'".
+ width += 1 + 1 + utf8.UTFMax + 1
+ }
+ }
if width > nByte {
// We're going to need a bigger boat.
buf = make([]byte, width)
