Hello, I barely know a thing about compression, so bear with me (this is probably a stupid and painfully obvious question). So lets say I have an XML file with a few tags. <verylongtagnumberone> <verylongtagnumbertwo> text </verylongtagnumbertwo> </verylongtagnumberone> Now lets say I have a bunch of these very long tags with...
Hi, I have the very common problem of creating an index for an in-disk array of strings. In short, I need to store the position of each string in the in-disk representation. For example, a very naive solution would be an index array as follows: uint64 idx[] = { 0, 20, 500, 1024, ..., 103434 }; Which says that the first string is at po...
So I've been thinking lately about how compression might be implemented, and what I've postulated so far is that it might be using a sort of HashTable of 'byte signature' keys with memory location values where that 'byte signature' should be replaced upon expansion of the compressed item in question. Is this far from the truth? How is ...
I've often wondered, if I load a compressed image file, edit it and the save it again, will it loose some quality? What if I use the same quality grade when saving, will the algorithms somehow detect that the file has already be compressed as a JPEG and therefore there is no point trying to compress the displayed representation again? W...
Hi all, I was wondering whether anyone knows of any tools available that perform the task of analyzing one or more CSS files, determining the similarity between the various rules within the files and presenting the user with options for the merging and reduction of rulesets. I ask this because a project I am working on has reached the p...
I am interfacing with a server that requires that data sent to it is compressed with Deflate algorithm (Huffman encoding + LZ77) and also sends data that I need to Inflate. I know that Python includes Zlib, and that the C libraries in Zlib support calls to Inflate and Deflate, but these apparently are not provided by the Python Zlib m...
Hello, I am an intern and was asked to do some research on SQL 2008 data compression. We want to store several parts of outlook emails in a table. The problem is that we want to store the entire email body in a field, but then want to compress it. Using Char() will not store the whole body, but will allow compression... using varchar() w...
Hi I have some C code that stores ASCII strings in memory as a four byte length followed by the string. The string lengths are in the range 10-250 bytes. To reduce occupancy I'd like to compress each string individually on the fly, still storing the length (of the compressed string) followed by the compressed string. I don't want to ...
I'm putting together a technical response to tender, one of the requirements is to pass messages using an extensible format over a narrow bandwidth network (10 bytes/sec or so). To make life easy on the server, which will be receiving info from 1000's of devices I'd like to use Xml. To help with the bandwidth issue I could use compressed...
Is there an open-source Java implementation of the VCDIFF binary diff format (decoder and encoder)? There are xdelta and open-vcdiff, but those are both C libraries. Alternatively, are the other formats/algorithms that one could use to generate diffs for binary files from Java? ...
We've run into a problem with IIS compression screwing up IE6. We are stuck on a shared host and we can't turn compression off at the server level. Is it possible for us to turn off IIS compression from our ASP.Net application? ...
m making project on double data compression which uses the lossless data compression technique.. can any one tell me how should i procede?? m making project for the first tim.. please help me frnds... ...
I'm writing a method which approximates the Kolmogorov complexity of a String by following the LZ78 algorithm, except instead of adding to a table I just keep a counter i.e i'm only interested in the size of the compression. The problem is that for large inputs it is taking hours. Is it the way I have implemented it? /** * Uses the ...
How to easy encode and "compress" URL/e-mail adress to string in PHP? String should be: difficult to decode by user as short as possible (compressed) similar URLs should be different after encoding not in database easy to decode/uncompress by PHP script ex. input -> output, stackoverflow.com/1/ -> "n3uu399", stackoverflow.com/2/ ...
I am looking for a compression algorithm (for a programming competition) and I need a full description of how to implement it (all technical details), any loseless and patent-free algorithm will do, but the ease of implementation is a bonus :) (Although possibly irrelevant) I plan to implement the algorithm in C++... Thanks in advance....
I've got some strings that I need to compress server-side in C#, then decompress client-side in JavaScript. What can I use to accomplish this? ...
I have written a java program for compression. I have compressed some text file. The file size after compression reduced. But when I tried to compress PDF file. I dinot see any change in file size after compression. So I want to know what other files will not reduce its size after compression. Thanks Sunil Kumar Sahoo ...
I'm searching for an algorithm to compress small text strings: 50-1000 bytes (i.e. URLs). Which algorithm works best for this? ...
I would like to know if compression algorithms always generate unique output for two different sets of files. Say, I have two files A and B, and say I am applying a compression algorithm (for instance like PKZIP - this could be any compression algorithm) for each of these files to get A.zip and B.zip respectively. Is it possible for A.z...
We have 3 HTTP Compression available in IIS 7.0 GZIP Encoding DEFLATE Encoding BZIP2 Encoding What are the difference between these three? Which is the best compression for security and performance? ...