compression

问题 I would like to deflate a small block of memory (<= 16 KiB) using zlib. The output is stored in a block of memory as well. No disk or database access here. According to the documentation, I should call deflate() repeatedly until the whole input is deflated. In between, I have to increase the size of the memory block where the output goes. However, that seems unnecessarily complicated and perhaps even inefficient. As I know the size of the input, can't I predetermine the maximum size needed

问题 I am trying to activate gzip compression on all JSON output on sails.js. I added this in config/http.js: order: [ 'startRequestTimer', 'cookieParser', 'session', 'myRequestLogger', 'bodyParser', 'handleBodyParserError', 'compress', 'methodOverride', 'poweredBy', '$custom', 'router', 'www', 'favicon', '404', '500' ], compress: require('compression')(), I know the compress: require('compression')() line is called because I try with a wrong value and it crashes. I restarted sails but the headers

问题 I have an iPhone app that overlays an image over a view created by a XIB, using CIFilter CIHardLightBlendMode. The view is 1000x1000 pixels, and I want to maintain that size until the end. This makes the image files about 1 MB as a png, if there is any complexity. I've tried using JPGs, but it doesn't overlay the image onto the view on a device (it works on the simulator). I've tried compressing the PNGs, but they get garbled when they get overlaid over the view (they look identical to the

问题 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

问题 So the compression process takes a chunk of binary data A and outputs a smaller chunk of binary data B . What characteristics of B make it unable to go through this process again? 回答1: Data has something called entropy: the amount of new information each new bit gives. For example, 10101010101010101010 has low entropy because you don't need the next bit to know what comes next. A perfect compression algorithm would compress to maximum entropy, so every bit gives information and so cannot be

问题 I'm working on a compression algorithm wherein we have to write code in C. The program takes a file and removes the most significant bit in every character and stores the compressed text in another file. I wrote a function called compress as shown below. I'm getting a seg fault while freeing out_buf. Any help will be a great pleasure. 回答1: You close out_fd twice, so of course the second time it is an invalid file descriptor. But more than that, you need to review your use of sizeof() which is

问题 It's a little strange I know, but I want to limit a program (for example the winrar app) resource usage. The reason: I have an old laptop, with overheating problem, so if I want to do a calculate intensive task (compress a >10GB folder), my laptop overheats and turns off. The question: Is it possible to limit an application's resource/CPU usage? For example, can I set somehow, that winrar can only use my CPU's 50%? I use windows 8.1, but answer for other OS is welcome. 回答1: See Are there

问题 I'm trying to decompress data compressed with zlib algorithm in C# using 2 most legitimate libraries compatible with zlib algorithm and I got similar exception thrown. Using DotNetZip: Ionic.Zlib.ZlibException: Bad state (invalid stored block lengths) Using Zlib.Net: inflate: invalid stored block lenghts but using same data as input to zlib-flate command on linux using only default parameters, works great and decompressed without any warnings (output is correct): zlib-flate -uncompress < .

问题 I have a hashMap that needs to travel from server to client over network. Now when the size increases beyond some limit provided at socket buffer the following exception is thrown. Caused by: weblogic.socket.MaxMessageSizeExceededException: Incoming message of size: '3002880' bytes exceeds the configured maximum of: '3000000' bytes for protocol: 't3' While googling it out I found that the socket size should be increased but that is not required as this is not such a good solution. Then I am

问题 In my project, I have some files related to items on Server as shown below: Item-1 => file1.txt, file2.pdf and file3.doc Item-2 => file4.pdf, file5.ppt Item-3 => file6.txt, file7.docx and file8.ppt .... I can get the above items by $this->getAllItems() and then loop through each item. I am trying to compress all these files in a structured way. So, that the user can understand files belong to which items. What I am trying to do is keep the files related to their respected items in a folder