deflate

Non symmetric java compression

由 耗尽温柔 提交于 2019-12-06 00:14:24
问题 I have a data sample: byte[] b = new byte[]{120, 1, -67, -107, -51, 106, 20, 81, 16, -123, 107, 18, -51, -60, 31, -30, 117, -4, -53, -60, -123, 25, 70, 71, 23, -111, 89, 12, 8, -83, 49, 4, -14, -93, -63, 73, 32, 89, -55, -112, -123, 10, -30, 66, 69, -110, 69, -64, -107, -77, 8, -72, 21, 23, -82, 5, -97, -64, 55, -48, -73, -16, 97, 4, -3, 14, -23, -110, 75, 59, 125, 39, 8, -10, -123, 51, -73, -86, -85, -6, 84, -99, -22, -18, 59, 53, 51, 27, 2, 95, 7, 24, 95, -36, 97, 95, 9, 102, -17, 46, -101,

AngularJS - How to deflate and encode/decode to base64 all jsons request?

由 北战南征 提交于 2019-12-05 22:11:56
问题 Lets say i have several $resources and some $http around my angular application: myApp.factory('Note', function($resource) { return $resource('http://', {id: '@id'}, { 'index': { method: 'GET', isArray: true }, 'update': { method: 'PUT'}, }); }); with controller myApp.controller('NotesController',function NotesController($scope, Note, AuthenticationService) { $scope.notes = Note.index({}, function(data){ console.log('success, got data: ', data); $scope.response = "yoy!" }, function(err){

PNG: deflate and zlib

由 試著忘記壹切 提交于 2019-12-05 20:02:58
I'm trying to understand compression in PNG - but I seem to find a lot of contradictory information online ... I would like to understand - how is searching done in the LZ77-part: hash table with linked lists? is this defined in deflate? or implemented in zlib? is there a choice of the search method? - can PNG encoders/decoders set some parameters for the compression (strategy, filter, etc.) or is there a default for PNG? - does the LZ77-part do greedy or lazy evaluation? or is this an option too? - and finally: the 2 Huffman trees, are they compressed in a third tree, and all three of them

How to compute good preset dictionary for deflate compression

由 穿精又带淫゛_ 提交于 2019-12-05 19:04:01
I have an opportunity to preset dictionary for deflate compression. It makes sense in my case, because data to be compressed is relatively small 1kb-3kb and I have a large sample of representative examples. Data to be compressed consists of arbitrary sequence of bytes, so tokenization etc. is not a good way to go. Also, data shows a lot of repetition (between data examples), so good dictionary could potentially give very good results. The question is how calculate good dictionary? Is there an algorithm which calculates optimal dictionary (given sample data)? I started looking at prefix trees,

The structure of Deflate compressed block

由 ☆樱花仙子☆ 提交于 2019-12-05 14:13:08
I have troubles with understanding Deflate algorithm ( RFC 1951 ). TL; DR How to parse Deflate compressed block 4be4 0200 ? I created a file with a letter and newline a\n in it, and run gzip a.txt . Resultant file a.txt.gz : 1f8b 0808 fe8b eb55 0003 612e 7478 7400 4be4 0200 07a1 eadd 0200 0000 I understand that first line is header with additional information, and last line is CRC32 plus size of input ( RFC 1951 ). These two gives no trouble to me. But how do I interpret the compressed block itself (the middle line)? Here's hexadecimal and binary representation of it: 4be4 0200 0100 1011 1110

Is there a GZIP merger that merges two GZIP files without decompressing them?

由 自古美人都是妖i 提交于 2019-12-05 12:34:41
问题 Let's say there's a.gz, and b.gz. $ gzip_merge a.gz b.gz -output c.gz I'd like to have this program. Of course, $ cat a.gz b.gz > c.gz doesn't work. Because the final DEFLATE block of a.gz has BFINAL, and the GZIP header of b.gz. (Refer to RFC1951, RFC1952) But if you unset BFINAL, throw away the second GZIP header and walk through the byte boundaries of the second gzip file, you can merge it. In fact, I thought of writing an open source program for this matter, but didn't know how to publish

Reusing a data dictionary for 'Deflate' separate from the compressed data

由 天涯浪子 提交于 2019-12-05 09:49:45
I am storing many chunks of base64 encoded 64-bit doubles in an XML file. The double data all looks similar. The double data is currently being compressed using the java 'Deflate' algorithm before the encoding, however each chunk of binary data in the file will have its own deflate data dictionary, which is an overhead I would like to greatly lessen. The 'Deflater' class has a 'setDictionary' method which I would like to use. So questions are: 1). Does anyone have any suggestions for how to best build my own single custom data dictionary based on multiple sections of doubles (x8 bytes) that

GZip or Deflate for HTTP compression

由 梦想的初衷 提交于 2019-12-05 08:49:50
Which compression method is better? I've heard lots of back and forth about GZip being more widely used, but Deflate being faster (in some instances). Is there an accepted standard on which one to use and why? eigenein UPDATE According to the latest updates to the linked question, one should use GZip. See http://www.vervestudios.co/projects/compression-tests/results Old Answer Deflate is better . yorah Answers: http://www.stardeveloper.com/articles/display.html?article=2008111201&page=1 http://blog.usweb.com/archives/mod_deflate-vs-mod_gzip-comparing-the-two/ Why use deflate instead of gzip

Enable mod_deflate to send Content-Encoding: gzip

由 可紊 提交于 2019-12-05 08:10:45
EDIT I have found that the problem is actually php minify . This was sending the deflated content instead of Apache. I'll find more on this. According to High Performance Web Sites , if I enable mod_deflate in Apache 2.x, by adding the following line, it should send gzipped/delfated content: - AddOutputFilterByType DEFLATE text/html text/css application/x-javascript The book also says that gzip is more effective than deflate . I have enabled in httpd.conf by adding the same line. But Apache sends Content-Encoding: deflate . I tested with CURL using: - curl -i -H "Accept-Encoding: gzip" "http:/

JavaScript inflate implementation (possibly FF 3.6 only)

由 老子叫甜甜 提交于 2019-12-05 06:13:42
I'm writing some scripts that are using the HTML 5 file API in FireFox 3.6. I got some deflated (compressed) files, and I need to inflate (uncompress) them. I found a few scripts while googling, but none of them have tests. So I'm a bit reluctant to use them. My question is: Browsers can inflate. Can I somehow piggyback on the inflation by forging A XHR request? Or piggyback in any other way? Keep in mind, the script is currently FireFox 3.6 exclusive. It can't be an extension, though, I want it to be a regular webpage. Alternatively , are there any scripts that you know of that has tests
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