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Commit Graph

7 Commits

Author SHA1 Message Date
Nick Craig-Wood
578c521fc2 cmd/stringer: fix panic caused by integer overflow
When String() was called on the maximum value of an integer type (eg
255 for uint8) this would cause an integer overflow, which would cause
an index error later in the code.

Fixed by re-arranging the code slightly.

Fixes golang/go#10563

Change-Id: I9fd016afc5eea22adbc3843f6081091fd50deccf
Reviewed-on: https://go-review.googlesource.com/9255
Reviewed-by: Rob Pike <r@golang.org>
2015-06-02 19:44:20 +00:00
Rob Pike
575b88be8f stringer: avoid if's in the generated code
Suggestion by dsymonds: Save code not data.
Add an extra element to the index array and an if can be eliminated.

Old generated code:
const _Day_name = "MondayTuesdayWednesdayThursdayFridaySaturdaySunday"

var _Day_index = [...]uint8{6, 13, 22, 30, 36, 44, 50}

func (i Day) String() string {
	if i < 0 || i >= Day(len(_Day_index)) {
		return fmt.Sprintf("Day(%d)", i)
	}
	hi := _Day_index[i]
	lo := uint8(0)
	if i > 0 {
		lo = _Day_index[i-1]
	}
	return _Day_name[lo:hi]
}

New generated code:
const _Day_name = "MondayTuesdayWednesdayThursdayFridaySaturdaySunday"

var _Day_index = [...]uint8{0, 6, 13, 22, 30, 36, 44, 50}

func (i Day) String() string {
	if i < 0 || i+1 >= Day(len(_Day_index)) {
		return fmt.Sprintf("Day(%d)", i)
	}
	return _Day_name[_Day_index[i]:_Day_index[i+1]]
}

Change-Id: I6f46a4892d5813a12ec1ad01738c6a21c7e45172
Reviewed-on: https://go-review.googlesource.com/1990
Reviewed-by: David Symonds <dsymonds@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2014-12-22 20:58:05 +00:00
Rob Pike
d03e8a67df go.tools/cmd/stringer: delete needless subtraction of zero in generated code
LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/136270043
2014-09-05 17:05:28 -07:00
Rob Pike
d0448f16e3 go.tools/cmd/stringer: add end-to-end test that compiles, runs, and verifies the generated method
In the process, fix a bug in one of the method generators.

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/141130043
2014-09-05 15:42:23 -07:00
Rob Pike
75b67f833e go.tools/cmd/stringer: fix generated map code
Missed comment from previous code review.
Next up: execution tests so this won't happen again

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/134480043
2014-09-04 16:18:38 -07:00
Rob Pike
22ede605a7 go.tools/cmd/stringer: use const for names, slice for map strings
Improve the generated code by using a const instead of a var for the names string.
This requires some refactoring to get neat const() and var() blocks.
Also change the generate map code go use a single sliced string, to reduce the
size of the compiled representation (only one string value).

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/135450044
2014-09-04 16:06:51 -07:00
Rob Pike
9207f67279 go.tools/cmd/stringer: add tests
Refactor a little to make testing easier.
Add golden tests and a check fo splitIntoRuns, which is the subtlest piece.
Still to come: execution tests.

Also fix a few issues in the generated code.

LGTM=gri
R=gri
CC=golang-codereviews, josharian
https://golang.org/cl/134450044
2014-09-04 14:16:59 -07:00