strconv: document parsing of leading +/-

Explicitly document the handling of a sign prefix, and the interaction
between the sign and base prefixes.

Fixes #46641.

Change-Id: I3cd6773e3f074fe671a944a05a79d2408137fcd4
Reviewed-on: https://go-review.googlesource.com/c/go/+/325875
Trust: Damien Neil <dneil@google.com>
Run-TryBot: Damien Neil <dneil@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
This commit is contained in:
Damien Neil 2021-06-07 16:30:03 -07:00
parent df35ade067
commit 1402b27d46
2 changed files with 18 additions and 3 deletions

View File

@ -57,6 +57,8 @@ const IntSize = intSize
const maxUint64 = 1<<64 - 1
// ParseUint is like ParseInt but for unsigned numbers.
//
// A sign prefix is not permitted.
func ParseUint(s string, base int, bitSize int) (uint64, error) {
const fnParseUint = "ParseUint"
@ -159,10 +161,13 @@ func ParseUint(s string, base int, bitSize int) (uint64, error) {
// ParseInt interprets a string s in the given base (0, 2 to 36) and
// bit size (0 to 64) and returns the corresponding value i.
//
// The string may begin with a leading sign: "+" or "-".
//
// If the base argument is 0, the true base is implied by the string's
// prefix: 2 for "0b", 8 for "0" or "0o", 16 for "0x", and 10 otherwise.
// Also, for argument base 0 only, underscore characters are permitted
// as defined by the Go syntax for integer literals.
// prefix following the sign (if present): 2 for "0b", 8 for "0" or "0o",
// 16 for "0x", and 10 otherwise. Also, for argument base 0 only,
// underscore characters are permitted as defined by the Go syntax for
// integer literals.
//
// The bitSize argument specifies the integer type
// that the result must fit into. Bit sizes 0, 8, 16, 32, and 64

View File

@ -33,6 +33,9 @@ var parseUint64Tests = []parseUint64Test{
{"_12345", 0, ErrSyntax},
{"1__2345", 0, ErrSyntax},
{"12345_", 0, ErrSyntax},
{"-0", 0, ErrSyntax},
{"-1", 0, ErrSyntax},
{"+1", 0, ErrSyntax},
}
type parseUint64BaseTest struct {
@ -140,8 +143,10 @@ var parseInt64Tests = []parseInt64Test{
{"", 0, ErrSyntax},
{"0", 0, nil},
{"-0", 0, nil},
{"+0", 0, nil},
{"1", 1, nil},
{"-1", -1, nil},
{"+1", 1, nil},
{"12345", 12345, nil},
{"-12345", -12345, nil},
{"012345", 12345, nil},
@ -236,6 +241,11 @@ var parseInt64BaseTests = []parseInt64BaseTest{
{"0__12345", 0, 0, ErrSyntax},
{"01234__5", 0, 0, ErrSyntax},
{"012345_", 0, 0, ErrSyntax},
{"+0xf", 0, 0xf, nil},
{"-0xf", 0, -0xf, nil},
{"0x+f", 0, 0, ErrSyntax},
{"0x-f", 0, 0, ErrSyntax},
}
type parseUint32Test struct {