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| author | Robert Griesemer <gri@golang.org> | 2018-12-05 14:42:47 -0800 |
|---|---|---|
| committer | Robert Griesemer <gri@golang.org> | 2018-12-05 23:15:21 +0000 |
| commit | dc7808d4f2989fa0514fc0e4014616fdb8c4a764 (patch) | |
| tree | 1d29468c03f46b49da813b807c4b91dfca151d92 /src/cmd/compile/internal/syntax/source.go | |
| parent | 940e5bc5617ed86fcbf845fdd1973be984259a59 (diff) | |
| download | go-dc7808d4f2989fa0514fc0e4014616fdb8c4a764.tar.gz go-dc7808d4f2989fa0514fc0e4014616fdb8c4a764.zip | |
cmd/compile/internal/syntax: remove unused field in (scanner) source
The source.offs field was intended for computing line offsets which
may allow a tiny optimization (see TODO in source.go). We haven't
done the optimization, so for now just remove the field to avoid
confusion. It's trivially added if needed.
While at it, also:
- Fix comment for ungetr2.
- Make sure sentinel is present even if reading from the io.Reader failed.
Change-Id: Ib056c6478030b3fe5fec29045362c8161ff3d19e
Reviewed-on: https://go-review.googlesource.com/c/152763
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Diffstat (limited to 'src/cmd/compile/internal/syntax/source.go')
| -rw-r--r-- | src/cmd/compile/internal/syntax/source.go | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/src/cmd/compile/internal/syntax/source.go b/src/cmd/compile/internal/syntax/source.go index 62eb0fdc30..c6168b8594 100644 --- a/src/cmd/compile/internal/syntax/source.go +++ b/src/cmd/compile/internal/syntax/source.go @@ -33,7 +33,6 @@ type source struct { // source buffer buf [4 << 10]byte - offs int // source offset of buf r0, r, w int // previous/current read and write buf positions, excluding sentinel line0, line uint // previous/current line col0, col uint // previous/current column (byte offsets from line start) @@ -51,7 +50,6 @@ func (s *source) init(src io.Reader, errh func(line, pos uint, msg string)) { s.errh = errh s.buf[0] = utf8.RuneSelf // terminate with sentinel - s.offs = 0 s.r0, s.r, s.w = 0, 0, 0 s.line0, s.line = 0, linebase s.col0, s.col = 0, colbase @@ -68,7 +66,8 @@ func (s *source) ungetr() { // ungetr2 is like ungetr but enables a 2nd ungetr. // It must not be called if one of the runes seen -// was a newline. +// was a newline or had a UTF-8 encoding longer than +// 1 byte. func (s *source) ungetr2() { s.ungetr() // line must not have changed @@ -167,7 +166,6 @@ func (s *source) fill() { } n := s.r0 - 1 copy(s.buf[:], s.buf[n:s.w]) - s.offs += n s.r0 = 1 // eqv: s.r0 -= n s.r -= n s.w -= n @@ -189,6 +187,7 @@ func (s *source) fill() { } } + s.buf[s.w] = utf8.RuneSelf // sentinel s.ioerr = io.ErrNoProgress } |