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a3d1c1bdce
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Nigel Tao a3d1c1bdce image/jpeg: ignore extraneous data, the same as what libjpeg does. 
Fixes #4705.

Note that libjpeg will print a warning to stderr if there are many
extraneous bytes, but can be silent if the extraneous bytes can fit
into its int32 bit-buffer for Huffman decoding. I'm guessing that
this is why whatever encoder that produced the image filed for issue
4705 did not realize that they are, strictly speaking, generating an
invalid JPEG. That issue's attached image has two extraneous bytes.

For example, piping the program below into libjpeg's djpeg program
will print an "18 extraneous bytes" warning, even though N == 20.

$ cat main.go
package main

import (
        "bytes"
        "image"
        "image/color"
        "image/jpeg"
        "os"
)

const N = 20

func main() {
        // Encode a 1x1 red image.
        m := image.NewRGBA(image.Rect(0, 0, 1, 1))
        m.Set(0, 0, color.RGBA{255, 0, 0, 255})
        buf := new(bytes.Buffer)
        jpeg.Encode(buf, m, nil)
        b := buf.Bytes()
        // Strip the final "\xff\xd9" EOI marker.
        b = b[:len(b)-2]
        // Append N dummy 0x80 bytes to the SOS data.
        for i := 0; i < N; i++ {
                b = append(b, 0x80)
        }
        // Put back the "\xff\xd9" EOI marker.
        b = append(b, 0xff, 0xd9)
        os.Stdout.Write(b)
}
$ go run main.go | djpeg /dev/stdin > /tmp/foo.pnm
Corrupt JPEG data: 18 extraneous bytes before marker 0xd9

The resultant /tmp/foo.pnm is a perfectly good 1x1 red image.

R=r
CC=golang-dev
https://golang.org/cl/7750043
2013-03-13 10:44:45 +11:00
api api/next.txt: remove references to go/types, now in separate repo 2013-03-12 14:42:37 -07:00
doc spec: rewrite the description of panic and recover. 2013-03-12 14:28:16 -07:00
include lib9: add mktempdir, removeall, runprog 2013-03-06 15:48:28 -05:00
lib cmd/godoc: only show package documentation for commands 2013-03-11 13:38:59 -07:00
misc misc/bbedit, misc/notepadplus: remove executable bits from files. 2013-03-12 14:29:25 -07:00
src image/jpeg: ignore extraneous data, the same as what libjpeg does. 2013-03-13 10:44:45 +11:00
test test/bench/garbage: fix parser benchmark 2013-03-12 22:25:15 +01:00
.hgignore
.hgtags
AUTHORS A+C: Adrian Nos (individual CLA) 2013-03-12 11:45:30 -04:00
CONTRIBUTORS A+C: Adrian Nos (individual CLA) 2013-03-12 11:45:30 -04:00
favicon.ico godoc: update favicon 2012-10-11 17:02:36 +11:00
LICENSE
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README
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README 

This is the source code repository for the Go programming language.  

For documentation about how to install and use Go,
visit http://golang.org/ or load doc/install.html in your web browser.

After installing Go, you can view a nicely formatted
doc/install.html by running godoc --http=:6060
and then visiting http://localhost:6060/doc/install.html.

Unless otherwise noted, the Go source files are distributed
under the BSD-style license found in the LICENSE file.

--

Binary Distribution Notes

If you have just untarred a binary Go distribution, you need to set
the environment variable $GOROOT to the full path of the go
directory (the one containing this README).  You can omit the
variable if you unpack it into /usr/local/go, or if you rebuild
from sources by running all.bash (see doc/install.html).
You should also add the Go binary directory $GOROOT/bin
to your shell's path.

For example, if you extracted the tar file into $HOME/go, you might
put the following in your .profile:

    export GOROOT=$HOME/go
    export PATH=$PATH:$GOROOT/bin

See doc/install.html for more details.