Search Results

Search found 15607 results on 625 pages for 'embedded language'.

Page 140/625 | < Previous Page | 136 137 138 139 140 141 142 143 144 145 146 147  | Next Page >

  • Implementing Transparent Persistence

    - by Jules
    Transparent persistence allows you to use regular objects instead of a database. The objects are automatically read from and written to disk. Examples of such systems are Gemstone and Rucksack (for common lisp). Simplified version of what they do: if you access foo.bar and bar is not in memory, it gets loaded from disk. If you do foo.bar = baz then the foo object gets updated on disk. Most systems also have some form of transactions, and they may have support for sharing objects across programs and even across a network. My question is what are the different techniques for implementing these kind of systems and what are the trade offs between these implementation approaches?

    Read the article

  • Is there a website to lookup already common code functions?

    - by pinnacler
    I'm sitting here writing a function that I'm positive has been written before, somewhere on earth. It's just too common to have not been attempted, and I'm wondering why I can't just go to a website and search for a function that I can then copy and paste into my project in 2 seconds, instead of wasting my day reinventing the wheel. Sure there are certain libraries you can use, but where do you find these libraries and when they are absent, is there a site like I'm describing?

    Read the article

  • Which term to use when referring to functional data structures: persistent or immutable?

    - by Bob
    In the context of functional programming which is the correct term to use: persistent or immutable? When I Google "immutable data structures" I get a Wikipedia link to an article on "Persistent data structure" which even goes on to say: such data structures are effectively immutable Which further confuses things for me. Do functional programs rely on persistent data structures or immutable data structures? Or are they always the same thing?

    Read the article

  • validation of special characters

    - by jpallavi
    I want to validate login name with special characters !@#S%^*()+_-?/<:"';. space using regular expression in ruby on rails. These special characters should not be acceptable. What is the code for that? Thanks, Pallavi

    Read the article

  • Serializing persistent/functional data structures

    - by Rob
    Persistent data structures depend on the sharing of structure for efficiency. For an example, see here. How can I preserve the structure sharing when I serialize the data structures and write them to a file or database? If I just naively traverse the datastructures, I'll store the correct values, but I'll lose the structure sharing. I'd like to be able to save data-structures with shared components to a file, restore them, and still have most of the structure shared in the restored data.

    Read the article

  • Count seconds and minutes with MCU timer/interrupt?

    - by arynhard
    I am trying to figure out how to create a timer for my C8051F020 MCU. The following code uses the value passed to init_Timer2() with the following formula: 65535-(0.1 / (12/2000000)=48868. I set up the timer to count every time it executes and for every 10 counts, count one second. This is based on the above formula. 48868 when passed to init_Timer2 will produce a 0.1 second delay. It would take ten of them per second. However, when I test the timer it is a little fast. At ten seconds the timer reports 11 seconds, at 20 seconds the timer reports 22 seconds. I would like to get as close to a perfect second as I can. Here is my code: #include <compiler_defs.h> #include <C8051F020_defs.h> void init_Clock(void); void init_Watchdog(void); void init_Ports(void); void init_Timer2(unsigned int counts); void start_Timer2(void); void timer2_ISR(void); unsigned int timer2_Count; unsigned int seconds; unsigned int minutes; int main(void) { init_Clock(); init_Watchdog(); init_Ports(); start_Timer2(); P5 &= 0xFF; while (1); } //============================================================= //Functions //============================================================= void init_Clock(void) { OSCICN = 0x04; //2Mhz //OSCICN = 0x07; //16Mhz } void init_Watchdog(void) { //Disable watchdog timer WDTCN = 0xDE; WDTCN = 0xAD; } void init_Ports(void) { XBR0 = 0x00; XBR1 = 0x00; XBR2 = 0x40; P0 = 0x00; P0MDOUT = 0x00; P5 = 0x00; //Set P5 to 1111 P74OUT = 0x08; //Set P5 4 - 7 (LEDs) to push pull (Output) } void init_Timer2(unsigned int counts) { CKCON = 0x00; //Set all timers to system clock divided by 12 T2CON = 0x00; //Set timer 2 to timer mode RCAP2 = counts; T2 = 0xFFFF; //655535 IE |= 0x20; //Enable timer 2 T2CON |= 0x04; //Start timer 2 } void start_Timer2(void) { EA = 0; init_Timer2(48868); EA = 1; } void timer2_ISR(void) interrupt 5 { T2CON &= ~(0x80); P5 ^= 0xF0; timer2_Count++; if(timer2_Count % 10 == 0) { seconds++; } if(seconds % 60 == 0 && seconds != 0) { minutes++; } }

    Read the article

  • Determining the load on a particular core in a multicore processor

    - by S.Man
    In a multicore processor, there are ways to tell the particular application to run in either single core or 2 cores or 3 cores. During such scenarios, how will a scheduler be able to determine the load(number of threads) on a particular core in a multicore processor and accordingly distribute(balance) the load(allocate threads) across the various cores ?

    Read the article

  • What do you enjoy about programming?

    - by Earlz
    Some of us here(or is it just me?) enjoy programming. Even if we're not being paid for it, and in some cases, even though the end result will not do anything for us. For example, many people do the Project Euler problems just for fun, and in the end nothing was really "accomplished" materially. What is it that makes us enjoy programming? How is programming different from another job? You don't see an accountant going home to do some accounting on their own time just for the pure joy of it. How are we different? (also, if anyone has some ideas on how to tag this, then please do correct it for me.. )

    Read the article

  • Do similar passwords have similar hashes?

    - by SLC
    Our computer system at work requires users to change their password every few weeks, and you cannot have the same password as you had previously. It remembers something like 20 of your last passwords. I discovered most people simply increment a digit at the end of their password, so "thisismypassword1" becomes "thisismypassword2" then 3, 4, 5 etc. Since all of these passwords are stored somewhere, I wondered if there was any weakness in the hashes themselves, for standard hashing algorithms used to store passwords like MD5. Could a hacker increase their chances of brute-forcing the password if they have a list of hashes of similar passwords?

    Read the article

  • Is it kEatSpeed or kSpeedEat?

    - by bobobobo
    I have a bunch of related constants that are not identical. What's the better way to name them? way #1 kWalkSpeed kRunSpeed kEatSpeed kDrinkSpeed Or, way #2 kSpeedWalk kSpeedRun kSpeedEat kSpeedDrink If we evaluate these based on readability understandability not bug prone with subtle errors due to using wrong variable name I think way #1 wins readability, they tie for understandability, and way #2 wins for not bug prone. I'm not sure how often it happens to others, but when variable names like this get long, then its easy to write kSpeedEatingWhenInAHurry when you really meant kSpeedEatingWhenInHome, especially when using autocomplete. Any perspectives?

    Read the article

  • Find a regular expression that matches a string?

    - by Mirai
    I need a model for finding all of the regular expressions that would match a particular string. Basically, I need an algorithm for doing what I do to generate a regex search string from some pattern. My purpose for this to create a list of potential regular expressions from a selection of text and order that list from least specific (i.e. string of characters with abitrary length) to most specific (i.e. the string itself) to be used in text editor.

    Read the article

  • Starting a code library.

    - by Rob Stevenson-Leggett
    Hi, I've been meaning to start a library of reusable code snippets for a while and never seem to get round to it. I think my main problems are: Where to start. What structure should my library take? Should it be a compiled library (where appropriate or just classes I can drop into any project? Or a library project that can be included? In my experience, a built library will quickly become out of date and the source will get lost. So I'm leaning towards source libraries that I can export from SVN and include in any project. Intellectual property. I am employeed, so a lot of the code I write is not my IP. How can I ensure that I don't give my own IP away using it on projects in work and at home? I'm thinking the best way would be to licence my library with an open source licence and make sure I only add to it in my own time using my own equipment and therefore making sure that if I use it in a work project the same rules apply as if I was using a third party library. I write in many different languages and often would require two or more parts of this library. Should I look at implementing a few template projects and a core project for each of my chosen reusable components and languages? Has anyone else got this sort of library and how do you organise and update it?

    Read the article

  • Tree-like queues

    - by Rehno Lindeque
    I'm implementing a interpreter-like project for which I need a strange little scheduling queue. Since I'd like to try and avoid wheel-reinvention I was hoping someone could give me references to a similar structure or existing work. I know I can simply instantiate multiple queues as I go along, I'm just looking for some perspective by other people who might have better ideas than me ;) I envision that it might work something like this: The structure is a tree with a single root. You get a kind of "insert_iterator" to the root and then push elements onto it (e.g. a and b in the example below). However, at any point you can also split the iterator into multiple iterators, effectively creating branches. The branches cannot merge into a single queue again, but you can start popping elements from the front of the queue (again, using a kind of "visitor_iterator") until empty branches can be discarded (at your discretion). x -> y -> z a -> b -> { g -> h -> i -> j } f -> b Any ideas? Seems like a relatively simple structure to implement myself using a pool of circular buffers but I'm following the "think first, code later" strategy :) Thanks

    Read the article

  • Determining the order of a list of numbers (possibly without sorting)

    - by Victor Liu
    I have an array of unique integers (e.g. val[i]), in arbitrary order, and I would like to populate another array (ord[i]) with the the sorted indexes of the integers. In other words, val[ord[i]] is in sorted order for increasing i. Right now, I just fill in ord with 0, ..., N, then sort it based on the value array, but I am wondering if we can be more efficient about it since ord is not populated to begin with. This is more of a question out of curiousity; I don't really care about the extra overhead from having to prepopulate a list and then sort it (it's small, I use insertion sort). This may be a silly question with an obvious answer, but I couldn't find anything online.

    Read the article

  • What did you develop using a microcontroller?

    - by DR
    I've always been fascinated by microcontrollers and I'm planning to do a few hobby projects just to satisfy my inner geek :) I'm looking for ideas and motivation, so what did you develop using a microcontroller? If possible please state the microcontroller and/or development environment and an estimate on hardware costs beyond the basic equipment (if applicable). I'm interested in both successful and failed projects and any problems you encountered.

    Read the article

  • Creating huge images

    - by David Rutten
    My program has the feature to export a hi-res image of the working canvas to the disk. Users will frequently try to export images of about 20,000 x 10,000 pixels @ 32bpp which equals about 800MB. Add that to the serious memory consumption already going on in your average 3D CAD program and you'll pretty much guarantee an out-of-memory crash on 32-bit platforms. So now I'm exporting tiles of 1000x1000 pixels which the user has to stitch together afterwards in a pixel editor. Is there a way I can solve this problem without the user doing any work? I figured I could probably write a small exe that gets command-lined into the process and performs the stitching automatically. It would be a separate process and it would thus have 2GB of ram all to itself. Or is there a better way still? I'd like to support jpg, png and bmp so writing the image as a bytestream to the disk is not really possible.

    Read the article

  • why is optional chaining required in an if let statement

    - by b-ryan ca
    Why would the Swift compiler expect me to write if let addressNumber = paul.residence?.address?.buildingNumber?.toInt() { } instead of just writing: if let addressNumber = paul.residence.address.buildingNumber.toInt() { } The compiler clearly has the static type information to handle the conditional statement for the first dereference of the optional value and each following value. Why would it not continue to do so for the following statements?

    Read the article

  • Access files (.wav) in java package

    - by Highmastdon
    I want to access my .wav files which are in a package inside my project. For example I got two packages: package program package sounds From inside the program/something.class I'd like to play the sounds/asound.wav. How is this possible. clip.open(AudioSystem.getAudioInputStream(new File(filename))); clip.start(); //.... something inbetween clip.stop(); Here filename is C:\\projects\\something\\sounds\\, but how is it possible to just give a relative path to the asound.wav in the package?

    Read the article

< Previous Page | 136 137 138 139 140 141 142 143 144 145 146 147  | Next Page >