From 9f08c5c3830d42de9bf18b80b79516c61e1ea360 Mon Sep 17 00:00:00 2001 From: Nigel Tao Date: Fri, 13 Jun 2014 17:44:29 +1000 Subject: [PATCH] compress/lzw: add commentary that TIFF's LZW differs from the standard algorithm. See https://golang.org/cl/105750045/ for an implementation of TIFF's LZW. LGTM=r R=r CC=golang-codereviews https://golang.org/cl/102940043 --- src/pkg/compress/lzw/reader.go | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/src/pkg/compress/lzw/reader.go b/src/pkg/compress/lzw/reader.go index ef59699103..cd90c9c63a 100644 --- a/src/pkg/compress/lzw/reader.go +++ b/src/pkg/compress/lzw/reader.go @@ -6,12 +6,16 @@ // described in T. A. Welch, ``A Technique for High-Performance Data // Compression'', Computer, 17(6) (June 1984), pp 8-19. // -// In particular, it implements LZW as used by the GIF, TIFF and PDF file +// In particular, it implements LZW as used by the GIF and PDF file // formats, which means variable-width codes up to 12 bits and the first // two non-literal codes are a clear code and an EOF code. +// +// The TIFF file format uses a similar but incompatible version of the LZW +// algorithm. See the code.google.com/p/go.image/tiff/lzw package for an +// implementation. package lzw -// TODO(nigeltao): check that TIFF and PDF use LZW in the same way as GIF, +// TODO(nigeltao): check that PDF uses LZW in the same way as GIF, // modulo LSB/MSB packing order. import ( -- 2.50.0