code review 4548080: compress/lzw: do not use background goroutines

compress/lzw: do not use background goroutines

Programs expect that Read and Write are synchronous.
The background goroutines make the implementation
a little easier, but they introduce asynchrony that
trips up calling code.  Remove them.

[rsc, 2011-06-01 19:42:31]

Hello golang-dev (cc: golang-dev@googlegroups.com),

I'd like you to review this change to
https://go.googlecode.com/hg

[nigeltao, 2011-06-02 10:53:14]

http://codereview.appspot.com/4548080/diff/5001/src/pkg/compress/lzw/reader.go
File src/pkg/compress/lzw/reader.go (right):

http://codereview.appspot.com/4548080/diff/5001/src/pkg/compress/lzw/reader.g...
src/pkg/compress/lzw/reader.go:56: // overflow is the code at which hi overflows
the code width.
Add
// last is the most recently seen code, or decoderInvalidCode.
and fold "last uint16" on line 58 into line 57.

http://codereview.appspot.com/4548080/diff/5001/src/pkg/compress/lzw/reader.g...
src/pkg/compress/lzw/reader.go:195: continue
Should lines 195-198 instead be
} else {
  d.width++
  d.overflow <<= 1
}
otherwise you're not flushing when you're out of codes.

http://codereview.appspot.com/4548080/diff/5001/src/pkg/compress/lzw/reader.g...
src/pkg/compress/lzw/reader.go:214: return nil
d.err = os.EOF ??

[rsc, 2011-06-03 16:57:15]

Hello golang-dev@googlegroups.com, nigeltao@golang.org (cc:
golang-dev@googlegroups.com),

Please take another look.

[nigeltao, 2011-06-04 07:44:25]

LGTM.

[rsc, 2011-06-07 18:37:09]

*** Submitted as http://code.google.com/p/go/source/detail?r=9dfa626bfeb7 ***

compress/lzw: do not use background goroutines

Programs expect that Read and Write are synchronous.
The background goroutines make the implementation
a little easier, but they introduce asynchrony that
trips up calling code.  Remove them.

R=golang-dev, nigeltao
CC=golang-dev
http://codereview.appspot.com/4548080