compression

问题 I'm currently on a little project where I have to define several paths that need to be compressed into one single zip-file. Now the following case: One of those paths is a directory, which should be compressed recursively (including all files and sub-folders it contains). Before I compress, I check several things including permissions. If the current user, which wants to compress, doesn't have the permission to a file or folder it should be excluded. Now how can I exclude several files and

问题 Firehose is pushing data to s3 in snappy compressed form and its framing format is hadoop compatible. I am downloading that snappy file and trying to uncompress in scala using this library. val input: Array[Byte] = Files.readAllBytes(Paths.get("/path/to/prod-a8d272bb-b7af-4141-bdba-6965b343a75f.snappy")) val uncompressed: Array[Byte] = Snappy.uncompress(input) Which throws error Exception in thread "main" java.io.IOException: FAILED_TO_UNCOMPRESS(5) at org.xerial.snappy.SnappyNative.throw

问题 When accepting an input buffer, and knowing compression is a CPU bound task, does it needs to offer a callback? Is it just there to follow common practice like callback(err, result) ? Doc: http://nodejs.org/api/zlib.html#zlib_zlib_deflate_buf_callback 回答1: The compression/decompression is executed in a separate thread and not in the main thread. That is why a callback is needed for when the thread completes its work. The callback style is the same common signature used throughout node and

问题 I have a string for example: "10001000101010001" in PHP I am compressing it with gzcompress, but it compresses ASCII equivalent. I would like to compress the string as if it were binary data not it ASCII binary equivalent. Bascially I have 2 problems: how to convert a list of 1s and 0s into binary compress the resulting binary with gzcompress thanks in advance. 回答1: Take a look at the bindec() function. Basically you'll want something like (dry-coded, please test it yourself before blindly

问题 I have a buffer of let's say 4KB, containing data in JSON-like format. I need to add significantly more information (up to let's say 3x more) to it, but I have to fit in this small chunk of memory. I was thinking about using libZ to compress text, but I'm afraid it will not perform well since the data consists mostly of some unique substrings. What would you recommend in this situation? Thanks, Chris 回答1: Consider a fixed dictionary containing up to 32K of strings that you expect to appear in

问题 I am looking for a (prefferably small) open source library in C or C++ which I can include in my MIT licensed projects (hosted on google code). I am a hobby C/C++ programmist so I am not that advanced, however I know just the things I need to develop plugins for a application named "SA-MP" (works on Windows and Linux). What I am willing to make is an auto installer which will need to be able to uncompress compressed files (prefferably .zip, but any other file compression method will do!). I

问题 I am looking for a (prefferably small) open source library in C or C++ which I can include in my MIT licensed projects (hosted on google code). I am a hobby C/C++ programmist so I am not that advanced, however I know just the things I need to develop plugins for a application named "SA-MP" (works on Windows and Linux). What I am willing to make is an auto installer which will need to be able to uncompress compressed files (prefferably .zip, but any other file compression method will do!). I

问题 I am able to compress all kinds of files (.jpg, .mp4 etc.) but when I try to decompress these non-text files the program just returns an empty decompressed file... the weird part is that I am able to decompress plain text files just fine. When I compress my original file I put both the data needed to reconstruct the tree and the encoded bits in the same file. The format looks something like this: <n><value 1><frequency 1>...<value n><frequency n>[the compressed bytes] Where n is the total

问题 I have an embedded webserver that has a total of 2 Megs of space on it. Normally you gzip files for the clients benefit, but this would save us space on the server. I read that you can just gzip the js file and save it on the server. I tested that on IIS and I didn't have any luck at all. What exactly do I need to do on every step of the process to make this work? This is what I imagine it will be like: gzip foo.js change link in html to point to foo.js.gz instead of just .js Add some kind of

问题 I have an embedded webserver that has a total of 2 Megs of space on it. Normally you gzip files for the clients benefit, but this would save us space on the server. I read that you can just gzip the js file and save it on the server. I tested that on IIS and I didn't have any luck at all. What exactly do I need to do on every step of the process to make this work? This is what I imagine it will be like: gzip foo.js change link in html to point to foo.js.gz instead of just .js Add some kind of