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  • How much abstraction is too much?

    - by Daniel Bingham
    In an Object Oriented Program: How much abstraction is too much? How much is just right? I have always been a nuts and bolts kind of guy. I understood the concept behind high levels of encapsulation and abstraction, but always felt instinctively that adding too much would just confuse the program. I always tried to shoot for an amount of abstraction that left no empty classes or layers. And where in doubt, instead of adding a new layer to the hierarchy, I would try and fit something into the existing layers. However, recently I've been encountering more highly abstracted systems. Systems where everything that could require a representation later in the hierarchy gets one up front. This leads to a lot of empty layers, which at first seems like bad design. However, on second thought I've come to realize that leaving those empty layers gives you more places to hook into in the future with out much refactoring. It leaves you greater ability to add new functionality on top of the old with out doing nearly as much work to adjust the old. The two risks of this seem to be that you could get the layers you need wrong. In this case one would wind up still needing to do substantial refactoring to extend the code and would still have a ton of never used layers. But depending on how much time you spend coming up with the initial abstractions, the chance of screwing it up, and the time that could be saved later if you get it right - it may still be worth it to try. The other risk I can think of is the risk of over doing it and never needing all the extra layers. But is that really so bad? Are extra class layers really so expensive that it is much of a loss if they are never used? The biggest expense and loss here would be time that is lost up front coming up with the layers. But much of that time still might be saved later when one can work with the abstracted code rather than more low level code. So when is it too much? At what point do the empty layers and extra "might need" abstractions become overkill? How little is too little? Where's the sweet spot? Are there any dependable rules of thumb you've found in the course of your career that help you judge the amount of abstraction needed?

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  • Automatic incremental SQL Script generation for incremental, nightly builds when using Team Build in

    - by Steve Johnson
    hi all, hope that everybody here is OK. We are using VS 2008 as development tool, TFS 2008 as version control as well as build automation. Some of our developer use dbpro for databases changes and some use SQL Server management studio. I am trying to automate build for Web Application built using C# and VB.Net. Our scenario is such that we have a central database to which our web application connects. Whenever we supply our clients with a new functionality or a bug fix, we supply them incremental builds. The SQL script is checked into source control for every incremental build when they have made and tested there changes on our central DB Server. I want to generate Differential script that can be run at the client as an incremental update script. Now to come about it is a problem. Sometimes our developers tend to forget the database change-sets and the script in the source control is missing an SP or a two. Also, sometimes we need to insert default data into some of the tables that have strict stringent values and not test values. Like a table that contains Services provided by the panel, we add a new service name, signature, credentials and service address, etc etc in the ServiceTable. Besides this many other tables may have test data that may not be needed. If we use DataCompare, it will generate changeset for required data (important for client to enable certain services) and our test data that was added to the database as a result of our testing of the functionality or bug fix. Currently i am using SQLSchemaCompareTask (from Visual Studio 2008 Team Database Professional Power Tools API) in the TFSBuild.proj file of the build definition for TFS 2008. Using SQLSchemaCompareTask, the script generated contains database names like [dbo]. etc which are not desired as the script fails when run against SQL Server 2000 databses (Some of our client still use SQL Server 2000) databases as teh backend of the application. Also default data can't be generated by this process. To overcome this problem, i have to come up with a solution that can compare databases and generate script automatically that does not have to be manually reviewed again before being sent to the client. Please suggest effective methodology of such SQL script generation and suggest whether two different databases may be used or something ? Is there any toolkit or api that can enable build automation for SQL Server databases? Thank you all. Regards Steve

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  • TVirtualStringTree - resetting non-visual nodes and memory consumption

    - by Remy Lebeau - TeamB
    I have an app that loads records from a binary log file and displays them in a virtual TListView. There are potentially millions of records in a file, and the display can be filtered by the user, so I do not load all of the records in memory at one time, and the ListView item indexes are not a 1-to-1 relation with the file record offsets (List item 1 may be file record 100, for instance). I use the ListView's OnDataHint event to load records for just the items the ListView is actually interested in. As the user scrolls around, the range specified by OnDataHint changes, allowing me to free records that are not in the new range, and allocate new records as needed. This works fine, speed is tolerable, and the memory footprint is very low. I am currently evaluating TVirtualStringTree as a replacement for the TListView, mainly because I want to add the ability to expand/collapse records that span multiple lines (I can fudge it with the TListView by incrementing/decrementing the item count dynamically, but this is not as straight forward as using a real tree). For the most part, I have been able to port the TListView logic and have everything work as I need. I notice that TVirtualStringTree's virtual paradigm is vastly different, though. It does not have the same kind of OnDataHint functionality that TListView does (I can use the OnScroll event to fake it, which allows my memory buffer logic to continue working), and I can use the OnInitializeNode event to associate nodes with records that are allocated. However, once a tree node is initialized, it sees that it remains initialized for the lifetime of the tree. That is not good for me. As the user scrolls around and I remove records from memory, I need to reset those non-visual nodes without removing them from the tree completely, or losing their expand/collapse states. When the user scrolls them back into view, I can re-allocate the records and re-initialize the nodes. Basically, I want to make TVirtualStringTree act as much like TListView as possible, as far as its virtualization is concerned. I have seen that TVirtualStringTree has a ResetNode() method, but I encounter various errors whenever I try to use it. I must be using it wrong. I also thought of just storing a data pointer inside each node to my record buffers, and I allocate and free memory, update those pointers accordingly. The end effect does not work so well, either. Worse, my largest test log file has ~5 million records in it. If I initialize the TVirtualStringTree with that many nodes at one time (when the log display is unfiltered), the tree's internal overhead for its nodes takes up a whopping 260MB of memory (without any records being allocated yet). Whereas with the TListView, loading the same log file and all the memory logic behind it, I can get away with using just a few MBs. Any ideas?

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  • How to improve compare of item in sorted List<MyItem> with item before and after current item?

    - by Oliver
    Does anyone know about a good way to accomplish this task? Currently i'm doing it more ore less this way, but i'm feeling someway unhappy with this code, unable to say what i could immediately improve. So if anyone has a smarter way of doing this job i would be happy to know. private bool Check(List<MyItem> list) { bool result = true; //MyItem implements IComparable<MyItem> list.Sort(); for (int pos = 0; pos < list.Count - 1; pos++) { bool previousCheckOk = true; if (pos != 0) { if (!CheckCollisionWithPrevious(pos)) { MarkAsFailed(pos); result = false; previousCheckOk = false; } else { MarkAsGood(pos); } } if (previousCheckOk && pos != list.Count - 1) { if (!CheckCollisionWithFollowing(pos)) { MarkAsFailed(pos); result = false; } else { MarkAsGood(pos); } } } return result; } private bool CheckCollisionWithPrevious(int pos) { bool checkOk = false; var previousItem = _Item[pos - 1]; // Doing some checks ... return checkOk; } private bool CheckCollisionWithFollowing(int pos) { bool checkOk = false; var followingItem = _Item[pos + 1]; // Doing some checks ... return checkOk; } Update After reading the answer from Aaronaught and a little weekend to refill full mind power i came up with the following solution, that looks far better now (and nearly the same i got from Aaronaught): public bool Check(DataGridView dataGridView) { bool result = true; _Items.Sort(); for (int pos = 1; pos < _Items.Count; pos++) { var previousItem = _Items[pos - 1]; var currentItem = _Items[pos]; if (previousItem.CollidesWith(currentItem)) { dataGridView.Rows[pos].ErrorText = "Offset collides with item named " + previousItem.Label; result = false; sb.AppendLine("Line " + pos); } } dataGridView.Refresh(); return result; }

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  • Vector math, finding coördinates on a planar between 2 vectors

    - by Will Kru
    I am trying to generate a 3d tube along a spline. I have the coördinates of the spline (x1,y1,z1 - x2,y2,z2 - etc) which you can see in the illustration in yellow. At those points I need to generate circles, whose vertices are to be connected at a later stadium. The circles need to be perpendicular to the 'corners' of two line segments of the spline to form a correct tube. Note that the segments are kept low for illustration purpose. [apparently I'm not allowed to post images so please view the image at this link] http://img191.imageshack.us/img191/6863/18720019.jpg I am as far as being able to calculate the vertices of each ring at each point of the spline, but they are all on the same planar ie same angled. I need them to be rotated according to their 'legs' (which A & B are to C for instance). I've been thinking this over and thought of the following: two line segments can be seen as 2 vectors (in illustration A & B) the corner (in illustraton C) is where a ring of vertices need to be calculated I need to find the planar on which all of the vertices will reside I then can use this planar (=vector?) to calculate new vectors from the center point, which is C and find their x,y,z using radius * sin and cos However, I'm really confused on the math part of this. I read about the dot product but that returns a scalar which I don't know how to apply in this case. Can someone point me into the right direction? [edit] To give a bit more info on the situation: I need to construct a buffer of floats, which -in groups of 3- describe vertex positions and will be connected by OpenGL ES, given another buffer with indices to form polygons. To give shape to the tube, I first created an array of floats, which -in groups of 3- describe control points in 3d space. Then along with a variable for segment density, I pass these control points to a function that uses these control points to create a CatmullRom spline and returns this in the form of another array of floats which -again in groups of 3- describe vertices of the catmull rom spline. On each of these vertices, I want to create a ring of vertices which also can differ in density (amount of smoothness / vertices per ring). All former vertices (control points and those that describe the catmull rom spline) are discarded. Only the vertices that form the tube rings will be passed to OpenGL, which in turn will connect those to form the final tube. I am as far as being able to create the catmullrom spline, and create rings at the position of its vertices, however, they are all on a planars that are in the same angle, instead of following the splines path. [/edit] Thanks!

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  • Using commit monitors as a form of code review

    - by Jeff Dege
    I'm working in a small company - four developers, working on a variety of projects. We've been looking at what we can do as cost-effective methods of process improvement, and an idea came up. Given what we do, we often have single developers working on parts of a system, independently of the other developers. This can have a number of negative affects: A developer might not be fully aware of the context in which a change is being implemented, and make the change in a way that will meet the current customer's needs, but will break functionality that other customers depend on. A developer might make a change that breaks the current architectural design, introducing a dependency that will cause problems in future development. Other developers might not be aware of how the system has changed, in areas that they have not worked on. We've talked about doing code reviews, as a way of dealing with these issues. But we've not had much success when we tried. It takes a lot of time to prepare a change for a code review, and it takes everybody out of production while the review is being performed. And the benefits of any review we've tried has been minimal. We're using Subversion (with TortioseSVN) as our VCS. I've been looking at the SubVersion CommitMonitor tool, and wondering whether it might work as a sort of poor-man's code review. It lists every commit made on the repository, allowing someone to see the changes that have been made, the log messages made for that change, the files that were included in the change, and the specific lines in each file that were changed. Rather than scheduling a meeting, trying to get everybody together to review every change, we could just have every developer review every other developer's commits, at whatever time was convenient. This would keep every developer abreast of what changes were being made elsewhere in the system, and would have every change reviewed for customer conflicts and design consistency, at a fairly low cost. If someone saw a problem with the code that was being checked in, he could discuss it with the developer who did the commit, or more likely, schedule a meeting to discuss how the new feature could be implemented in a way that would not impact other users or screw up the architecture. Anyone else doing anything like this, using commit monitors for such a purpose?

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  • C# or C++ game: many 16 color images loaded into RAM. Efficient solution?

    - by user560639
    I am in the planning stages of creating a fighting game and am unsure how to handle one issue relating to memory. Background info: - Still debating whether to use C# (XNA) or C++. We do not want to commit to either until we have explored how to solve this problem in both languages. - Using a max of 256MB RAM would be great if possible. - Two characters will be present at a time, and these characters can only change between battles. There is time to load/free memory between battles, but the game needs to run at a constant 60 drawn frames per second during combat. Each frame is 16.67ms - The total number of images per character is in the low hundreds. Each image is roughly 200x400 pixels. Only one image from each character will be displayed at any given moment. Uncompressed, each image takes roughly 300kb from my calculations; upwards of 100MB for a whole character. This is pushing too close to the 256MB limit given that memory will be needed for some other resources as well. Since each image can be made with a total of 16 colors. Theoretically I should be able to use 1/8th the space if I can take advantage of this. I've looked around but haven't found any word of native support for paletted images. (Storing each pixel using fewer bits that each map to a 32-bit RGBa color) I was considering making my own file format with 4 bits per pixel (and some extra palette info), loading all the images of this new format into RAM before battle, and then when drawing any specific image, decompress only that image into a raw image so it can be rendered properly. I don't know if it's realistic to perform so many assignment operations (appx 200x400 for each character = 160k) each frame. It sounds very hacky to me. Does anyone have advice on whether my solution sounds reasonable, and if there is perhaps a better one available? Thanks so much! (I also attempted to use an image with only 1 channel, then use a shader to perform a series of if statements to translate various values into other colors. Unfortunately, there were too many lines of code for the shader. It is also rather hacky and does not scale well.)

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  • Looking for efficient scaling patterns for Silverlight application with distributed text-file data s

    - by Edward Tanguay
    I'm designing a Silverlight software solution for students and teachers to record flashcards, e.g. words and phrases that students find while reading and errors that teachers notice while teaching. Requirements are: each person publishes his own flashcards in a file on a web server, e.g. http://:www.mywebserver.com/flashcards.txt other people subscribe to that person's flashcards by using a Silverlight flashcard reader that I have developed and entering the URLs of flashcard files they want to subscribe to, URLs and imported flashcards being saved in IsolatedStorage the flashcards.txt file has the following simple format: title, then blocks of question/answers: Jim Smith's flashcards from English class 53-222, winter semester 2009 ==fla Das kann nicht sein. That can't be. ==fla Es sei denn, er kommt nicht. Unless he doesn't come. The user then makes public the URL to his flashcard file and other readers begin reading in his flashcards. In order to lower the bar for non-technical users to contribute, it will even be possible for them to save this text in a Google Document, which they publish and distribute the URL. The flashcard readers will then recognize it is a google document and perform the necessary screen scraping to get at the raw text. I have two technical questions about this approach: What is a best way to plan now for scalability issues: e.g. if your reader is subscribed to 10 flashcard files that are each 200K, it will have to download 2MB of text just to find out if any new flashcards are available. Or can I somehow accurately and consistently get at the last update date/time of text files on servers and published google docs? Each reader will have the ability to allow the person to test himself on imported flashcards and add meta information to them, e.g. categorize them, edit them, etc. This information will be stored in IsolatedStorage along with the important flashcards themselves. What is a good pattern to allow these readers to share and synchronize this meta data, e.g. so when you are looking at a flashcard you can see that 5 other people have made corrections to it. The best solution I can think of now is that the Silverlight readers will have to republish their data to a central database, but then there is the problem of uniquely identifying each flashcard, the best approach seems to be URL + position-in-file, or even better URL + original text of both question and answer fields, but both of these have their obvious drawbacks. The main requirement is that the bar for participation is kept as low as possible, i.e. type text in a google document, publish it, distribute the URL, and you're publishing within the flashcard community. So I want to come up with the most efficient technical solutions in order to compensate for the lack of database, lack of unique ids, etc. For those who have designed or developed similar non-traditional, distributed database projects like this, what advice, experience or best-practice tips you can share on the above two points?

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  • TVirtualStringTree - resetting non-visual nodes and memory comsumption

    - by Remy Lebeau - TeamB
    I have an app that loads records from a binary log file and displays them in a virtual TListView. There are potentially millions of records in a file, and the display can be filtered by the user, so I do not load all of the records in memory at one time, and the ListView item indexes are not a 1-to-1 relation with the file record offsets (List item 1 may be file record 100, for instance). I use the ListView's OnDataHint event to load records for just the items the ListView is actually interested in. As the user scrolls around, the range specified by OnDataHint changes, allowing me to free records that are not in the new range, and allocate new records as needed. This works fine, speed is tolerable, and the memory footprint is very low. I am currently evaluating TVirtualStringTree as a replacement for the TListView, mainly because I want to add the ability to expand/collapse records that span multiple lines (I can fudge it with the TListView by incrementing/decrementing the item count dynamically, but this is not as straight forward as using a real tree). For the most part, I have been able to port the TListView logic and have everything work as I need. I notice that TVirtualStringTree's virtual paridigm is vastly different, though. It does not have the same kind of OnDataHint functionality that TListView does (I can use the OnScroll event to fake it, which allows my memory buffer logic to continue working), and I can use the OnInitializeNode event to associate nodes with records that are allocated. However, once a tree node is initialized, it sees that it remains initialized for the lifetime of the tree. That is not good for me. As the user scrolls around and I remove records from memory, I need to reset those non-visual nodes without removing them from the tree completely, or losing their expand/collapse states. When the user scrolls them back into view, I can re-allocate the records and re-initialize the nodes. Basically, I want to make TVirtualStringTree act as much like TListView as possible, as far as its virtualization is concerned. I have seen that TVirtualStringTree has a ResetNode() method, but I encounter various errors whenever I try to use it. I must be using it wrong. I also thought of just storing a data pointer inside each node to my record buffers, and I allocate and free memory, update those pointers accordingly. The end effect does not work so well, either. Worse, my largest test log file has ~5 million records in it. If I initialize the TVirtualStringTree with that many nodes at one time (when the log display is unfiltered), the tree's internal overhead for its nodes takes up a whopping 260MB of memory (without any records being allocated yet). Whereas with the TListView, loading the same log file and all the memory logic behind it, I can get away with using just a few MBs. Any ideas?

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  • Address book with C programming; cannot compile my code.

    - by osabri
    I've divided my code into small programs so it can be easy to excute /* ab_error.c : in case of errors following messages will be displayed */ #include "adressbook.h" static char *errormsg[] = { "", "\nNot enough space on disk", "\nCannot open file", "\nCannot read file", "\nCannot write file" }; void check(int error) { switch(error) { case 0: return; case 1: write_file(); case 2: case 3: case 4: system("cls"); fputs(errormsg[error], stderr); exit(error); } } 2nd /* ab_fileio.c : functions for file input/output */ #include "adressbook.h" static char ab_file[] = "ADRESSBOOK.DAT"; //file to save the entries int read_file(void) { int error = 0; FILE *fp; ELEMENT *new_e, *last_e = NULL; DATA buffer; if( (fp = fopen(ab_file, "rb")) == NULL) return -1; //no file found while (fread(&buffer, sizeof(DATA), 1, fp) == 1) //reads one list element after another { if( (new_e = make_element()) == NULL) { error = 1; break; //not enough space } new_e->person = buffer; //copy data to new element new_e->next = NULL; if(hol.first == NULL) //list is empty? hol.first = new_e; //yes else last_e->next = new_e; //no last_e = new_e; ++hol.amount; } if( !error && !feof(fp) ) error = 3; //cannot read file fclose(fp); return error; } /*-------------------------------*/ int write_file(void) { int error = 0; FILE *fp; ELEMENT *p; if( (p = hol.first) == NULL) return 0; //list is empty if( (fp = fopen(ab_file, "wb")) == NULL) return 2; //cannot open while( p!= NULL) { if( fwrite(&p->person, sizeof(DATA), 1, fp) < 1) { error = 4; break; //cannot write } p = p->next; } fclose(fp); return error; } 3rd /* ab_list.c : functions to manipulate the list */ #include "adressbook.h" HOL hol = {0, NULL}; //global definition for head of list /* -------------------- */ ELEMENT *make_element(void) { return (ELEMENT *)malloc( sizeof(ELEMENT) ); } /* -------------------- */ int ins_element( DATA *newdata) { ELEMENT *new_e, *pre_p; if((new_e = make_element()) == NULL) return 1; new_e ->person = *newdata; // copy data to new element pre_p = search(new_e->person.family_name); if(pre_p == NULL) //no person in list { new_e->next = hol.first; //put it to the begin hol.first = new_e; } else { new_e->next = pre_p->next; pre_p->next = new_e; } ++hol.amount; return 0; } int erase_element( char name, char surname ) { return 0; } /* ---------------------*/ ELEMENT *search(char *name) { ELEMENT *sp, *retp; //searchpointer, returnpointer retp = NULL; sp = hol.first; while(sp != NULL && sp->person.family_name != name) { retp = sp; sp = sp->next; } return(retp); } 4th /* ab_screen.c : functions for printing information on screen */ #include "adressbook.h" #include <conio.h> #include <ctype.h> /* standard prompts for in- and output */ static char pgmname[] = "---- Oussama's Adressbook made in splendid C ----"; static char options[] = "\ 1: Enter new adress\n\n\ 2: Delete entry\n\n\ 3: Change entry\n\n\ 4: Print adress\n\n\ Esc: Exit\n\n\n\ Your choice . . .: "; static char prompt[] = "\ Name . . . .:\n\ Surname . . :\n\n\ Street . . .:\n\n\ House number:\n\n\ Postal code :\n\n\ Phone number:"; static char buttons[] = "\ <Esc> = cancel input <Backspace> = correct input\ <Return> = assume"; static char headline[] = "\ Name Surname Street House Postal code Phone number \n\ ------------------------------------------------------------------------"; static char further[] = "\ -------- continue with any key --------"; /* ---------------------------------- */ int menu(void) //show menu and read user input { int c; system ("cls"); set_cur(0,20); puts(pgmname); set_cur(6,0); printf("%s", options); while( (c = getch()) != ESC && (c < '1' || c > '4')) putch('\a'); return c; } /* ---------------------------------- */ int print_adr_book(void) //display adressbook { int line = 1; ELEMENT *p = hol.first; system("cls"); set_cur(0,20); puts(pgmname); set_cur(2,0); puts(headline); set_cur(5,0); while(p != NULL) //run through list and show entries { printf("%5d %-15s ",line, p->person.family_name); printf("%-12s %-15s ", p->person.given_name, p->person.street); printf("%-4d %-5d %-12d\n",p->person.house_number, p->person.postal_code, p->person.phone); p = p->next; if( p == NULL || ++line %16 == 1) //end of list or screen is full { set_cur(24,0); printf("%s",further); if( getch() == ESC) return 0; set_cur(5,0); scroll_up(0,5,24);//puts(headline); } } return 0; } /* -------------------------------------------*/ int make_entry(void) { char cache[50]; DATA newperson; ELEMENT *p; while(1) { system("cls"); set_cur(0,20); puts(pgmname); set_cur(6,0); puts("Please enter new data:"); set_cur(10,0); puts(prompt); set_cur(24,0); printf("%s",buttons); balken(10, 25, MAXL, ' ',0x70); //input name if(input(newperson.family_name, MAXL, ESC, CR) == ESC) return 0; balken(12,25, MAXL, ' ', 0x70); //surname if(input(newperson.given_name, MAXL, ESC, CR) == ESC) return 0; balken(14,25, 30, ' ', 0x70); //street if(input(newperson.street, 30, ESC, CR) == ESC) return 0; balken(16,25, 4, ' ',0x70); //housenumber if(input(cache, 4, ESC, CR) == ESC) return 0; newperson.house_number = atol(cache); //to string balken(18,25, 5, ' ',0x70); //postal code if(input(cache, 5, ESC, CR) == ESC) return 0; newperson.postal_code = atol(cache); //to string balken(20,25, 20, ' ',0x70); //phone number if(input(cache, 20, ESC, CR) == ESC) return 0; newperson.phone = atol(cache); //to string p = search(newperson.phone); if( p!= NULL && p->person.phone == newperson.phone) { set_cur(22,25); puts("phonenumber already exists!"); set_cur(24,0); printf("%s, further"); getch(); continue; } } } 5th /* adress_book_project.c : main program to create an adressbook */ /* copyrights by Oussama Sabri, June 2010 */ #include "adressbook.h" //project header file int main() { int rv, cmd; //return value, user command if ( (rv = read_file() ) == -1) // no data saved yet rv = make_entry(); check(rv); //prompts an error and quits program on disfunction do { switch (cmd = menu())//calls menu and gets user input back { case '1': rv = make_entry(); break; case '2': //delete entry case '3': //changes entry rv = change_entry(cmd); break; case '4': //prints adressbook on screen rv = print_adr_book(); break; case ESC: //end of program system ("cls"); rv = 0; break; } }while(cmd!= ESC); check ( write_file() ); //save adressbook return 0; } 6th /* Getcb.c --> Die Funktion getcb() liefert die naechste * * Tastatureingabe (ruft den BIOS-INT 0x16 auf). * * Return-Wert: * * ASCII-Code bzw. erweiterter Code + 256 */ /* Hinweis: Es muss ein DOS-Compiler verwendet werden. * * (z.B. der GNU-Compiler fuer DOS auf der CD) */ #include <dos.h> int getcb(void) { union REGS intregs; intregs.h.ah = 0; // Subfunktion 0: ein Zeichen // von der Tastatur lesen. int86( 0x16, &intregs, &intregs); if( intregs.h.al != 0) // Falls ASCII-Zeichen, return (intregs.h.al); // dieses zurueckgeben. else // Sonst den erweiterten return (intregs.h.ah + 0x100); // Code + 256 } 7th /* PUTCB.C --> enthaelt die Funktionen * * - putcb() * * - putcb9() * * - balken() * * - input() * * * * Es werden die Funktionen 9 und 14 des Video-Interrupts * * (ROM-BIOS-Interrupt 0x10) verwendet. * * * * Die Prototypen dieser Funktionen stehen in BIO.H */ /* Hinweis: Es muss ein DOS-Compiler verwendet werden. * * (z.B. der GNU-Compiler fuer DOS auf der CD) */ #include <dos.h> #define VIDEO_INT 0x10 /*---------------------------------------------------------------- * putcb(c) gibt das Zeichen auf der aktuellen Cursor-Position * am Bildschirm aus. Der Cursor wird versetzt. * Steuerzeichen Back-Space, CR, LF und BELL werden * ausgefuehrt. * Return-Wert: keiner */ void putcb(unsigned char c) /* Gibt das Zeichen in c auf */ { /* den Bildschirm aus. */ union REGS intregs; intregs.h.ah = 14; /* Subfunktion 14 ("Teletype") */ intregs.h.al = c; intregs.h.bl = 0xf; /* Vordergrund-Farbe im */ /* Grafik-Modus. */ int86(VIDEO_INT, &intregs, &intregs); } /*---------------------------------------------------------------- * putcb9(c,count,mode) gibt das Zeichen in c count-mal im * angegebenen Modus auf der aktuellen * Cursor-Position am Bildschirm aus. * Der Cursor wird nicht versetzt. * * Return-Wert: keiner */ void putcb9( unsigned char c, /* das Zeichen */ unsigned count, /* die Anzahl */ unsigned mode ) /* Low-Byte: das Atrribut */ { /* High-Byte: die Bildschirmseite*/ union REGS intregs; intregs.h.ah = 9; /* Subfunktion 9 des Int 0x10 */ intregs.h.al = c; intregs.x.bx = mode; intregs.x.cx = count; int86( VIDEO_INT, &intregs, &intregs); } /*---------------------------------------------------------------- * balken() positioniert den Cursor und zeichnet einen Balken, * wobei Position, L„nge, Fllzeichen und Attribut * als Argumente bergeben werden. * Der Cursor bleibt auf der ersten Position im Balken. */ void balken( unsigned int zeile, /* Start-Position */ unsigned int spalte, unsigned int laenge, /* Laenge des Balkens */ unsigned char c, /* Fuellzeichen */ unsigned int modus) /* Low-Byte: Attribut */ /* High-Byte: Bildschirmseite */ { union REGS intregs; intregs.h.ah = 2; /* Cursor auf der angegebenen */ intregs.h.dh = zeile; /* Bildschirmseite versetzen. */ intregs.h.dl = spalte; intregs.h.bh = (modus >> 8); int86(VIDEO_INT, &intregs, &intregs); putcb9(c, laenge, modus); /* Balken ausgeben. */ } /*---------------------------------------------------------------- * input() liest Zeichen von der Tastatur ein und haengt '\0' an. * Mit Backspace kann die Eingabe geloescht werden. * Das Attribut am Bildschirm bleibt erhalten. * * Argumente: 1. Zeiger auf den Eingabepuffer. * 2. Anzahl maximal einzulesender Zeichen. * 3. Die optionalen Argumente: Zeichen, mit denen die * Eingabe abgebrochen werden kann. * Diese Liste muá mit CR = '\r' enden! * Return-Wert: Das Zeichen, mit dem die Eingabe abgebrochen wurde. */ #include <stdarg.h> int getcb( void); /* Zum Lesen der Tastatur */ int input(char *puffer, int max,... ) { int c; /* aktuelles Zeichen */ int breakc; /* Abruchzeichen */ int nc = 0; /* Anzahl eingelesener Zeichen */ va_list argp; /* Zeiger auf die weiteren Arumente */ while(1) { *puffer = '\0'; va_start(argp, max); /* argp initialisieren */ c = getcb(); do /* Mit Zeichen der Abbruchliste vergleichen */ if(c == (breakc = va_arg(argp,int)) ) return(breakc); while( breakc != '\r' ); va_end( argp); if( c == '\b' && nc > 0) /* Backspace? */ { --nc; --puffer; putcb(c); putcb(' '); putcb(c); } else if( c >= 32 && c <= 255 && nc < max ) { ++nc; *puffer++ = c; putcb(c); } else if( nc == max) putcb('\7'); /* Ton ausgeben */ } } 8th /* Video.c --> Enthaelt die Funktionen * cls(), * scroll_up(), scroll_down(), * set_cur(), get_cur(), * set_screen_page(), get_screen_page() * * Die Prototypen dieser Funktionen befinden sich in BIO.H */ /* Hinweis: Es muss ein DOS-Compiler verwendet werden. * * (z.B. der GNU-Compiler fuer DOS auf der CD) */ #include <dos.h> #include "bio.h" #define VIDEO_INT 0x10 typedef unsigned char BYTE; void scroll_up( int anzahl, int anf_zeile, int end_zeile) { /* Fenster hoch rollen. */ union REGS intregs; intregs.x.ax = 0x600 + anzahl; /* Subfunktion AH = 6, */ /* AL = Anzahl Zeilen. */ intregs.x.cx = anf_zeile << 8; /* CH=anf_zeile, cl=0 */ intregs.x.dx = (end_zeile <<8) | 79; /* DH=end_zeile,DL=79 */ intregs.h.bh = 7; /* normales Attribut */ int86(VIDEO_INT, &intregs, &intregs); } void scroll_down( int anzahl, int anf_zeile, int end_zeile) { /* Fenster runter rollen. */ union REGS intregs; intregs.x.ax = 0x700 + anzahl; /* Subfunktion AH = 7, */ /* AL = Anzahl Zeilen. */ intregs.x.cx = anf_zeile << 8; /* CH=anf_zeile, cl=0 */ intregs.x.dx = (end_zeile <<8) | 79; /* DH=end_zeile,DL=79 */ intregs.h.bh = 7; /* normales Attribut */ int86(VIDEO_INT, &intregs, &intregs); } void set_cur( int zeile, int spalte) /* versetzt den Cursor */ { /* der aktuellen Bildschirmseite.*/ union REGS intregs; intregs.h.ah = 2; intregs.h.dh = (BYTE)zeile; intregs.h.dl = (BYTE)spalte; intregs.h.bh = (BYTE)get_screen_page(); int86(VIDEO_INT, &intregs, &intregs); } void get_cur(int *zeile, int *spalte) /* holt die Cursor- */ { /* Position der aktuellen Bildschirmseite.*/ union REGS intregs; intregs.h.ah = 3; intregs.h.bh = (BYTE)get_screen_page(); int86(VIDEO_INT, &intregs, &intregs); *zeile = (unsigned)intregs.h.dh; *spalte = (unsigned)intregs.h.dl; } void cls(void) { scroll_up(0,0,24); /* Gesamten Bildschirm loeschen. */ set_cur(0,0); /* Cursor in Home-Position. */ } int get_screen_page(void) /* Aktuelle Bildschirmseite holen.*/ { union REGS intregs; intregs.h.ah = 15; /* Subfunktion AH = 15: */ /* Bildschirm-Modus feststellen. */ int86(VIDEO_INT, &intregs, &intregs); return (intregs.h.bh); } void set_screen_page(int seite) /* setzt die aktive Seite des */ { /* Bildschirmpuffers auf die */ /* angegebene Seite. */ union REGS intregs; intregs.x.ax = 0x500 + seite; /* Subfunktion AH = 5 */ int86(VIDEO_INT, &intregs, &intregs); } /* ------------------------------------------------------------- Ein kleines Testprogramm : */ /* #include <stdio.h> int main() { cls(); set_cur(23, 0); printf("Weiter mit <Return>\n"); set_cur(12, 20); printf("Ein Test!\n"); getchar(); scroll_up(3, 5, 20); getchar(); scroll_down(6, 5, 20); getchar(); set_screen_page(1); printf("\nAuf der 2. Seite !\n"); getchar(); set_screen_page(0); set_cur(0,0); printf("\nWieder auf der 1. Seite !\n"); getchar(); cls(); return 0; } */ /* Video.c --> Enthaelt die Funktionen * cls(), * scroll_up(), scroll_down(), * set_cur(), get_cur(), * set_screen_page(), get_screen_page() * * Die Prototypen dieser Funktionen befinden sich in BIO.H */ /* Hinweis: Es muss ein DOS-Compiler verwendet werden. * * (z.B. der GNU-Compiler fuer DOS auf der CD) */ #include <dos.h> #include "bio.h" #define VIDEO_INT 0x10 typedef unsigned char BYTE; void scroll_up( int anzahl, int anf_zeile, int end_zeile) { /* Fenster hoch rollen. */ union REGS intregs; intregs.x.ax = 0x600 + anzahl; /* Subfunktion AH = 6, */ /* AL = Anzahl Zeilen. */ intregs.x.cx = anf_zeile << 8; /* CH=anf_zeile, cl=0 */ intregs.x.dx = (end_zeile <<8) | 79; /* DH=end_zeile,DL=79 */ intregs.h.bh = 7; /* normales Attribut */ int86(VIDEO_INT, &intregs, &intregs); } void scroll_down( int anzahl, int anf_zeile, int end_zeile) { /* Fenster runter rollen. */ union REGS intregs; intregs.x.ax = 0x700 + anzahl; /* Subfunktion AH = 7, */ /* AL = Anzahl Zeilen. */ intregs.x.cx = anf_zeile << 8; /* CH=anf_zeile, cl=0 */ intregs.x.dx = (end_zeile <<8) | 79; /* DH=end_zeile,DL=79 */ intregs.h.bh = 7; /* normales Attribut */ int86(VIDEO_INT, &intregs, &intregs); } void set_cur( int zeile, int spalte) /* versetzt den Cursor */ { /* der aktuellen Bildschirmseite.*/ union REGS intregs; intregs.h.ah = 2; intregs.h.dh = (BYTE)zeile; intregs.h.dl = (BYTE)spalte; intregs.h.bh = (BYTE)get_screen_page(); int86(VIDEO_INT, &intregs, &intregs); } void get_cur(int *zeile, int *spalte) /* holt die Cursor- */ { /* Position der aktuellen Bildschirmseite.*/ union REGS intregs; intregs.h.ah = 3; intregs.h.bh = (BYTE)get_screen_page(); int86(VIDEO_INT, &intregs, &intregs); *zeile = (unsigned)intregs.h.dh; *spalte = (unsigned)intregs.h.dl; } void cls(void) { scroll_up(0,0,24); /* Gesamten Bildschirm loeschen. */ set_cur(0,0); /* Cursor in Home-Position. */ } int get_screen_page(void) /* Aktuelle Bildschirmseite holen.*/ { union REGS intregs; intregs.h.ah = 15; /* Subfunktion AH = 15: */ /* Bildschirm-Modus feststellen. */ int86(VIDEO_INT, &intregs, &intregs); return (intregs.h.bh); } void set_screen_page(int seite) /* setzt die aktive Seite des */ { /* Bildschirmpuffers auf die */ /* angegebene Seite. */ union REGS intregs; intregs.x.ax = 0x500 + seite; /* Subfunktion AH = 5 */ int86(VIDEO_INT, &intregs, &intregs); } /* ------------------------------------------------------------- Ein kleines Testprogramm : */ /* #include <stdio.h> int main() { cls(); set_cur(23, 0); printf("Weiter mit <Return>\n"); set_cur(12, 20); printf("Ein Test!\n"); getchar(); scroll_up(3, 5, 20); getchar(); scroll_down(6, 5, 20); getchar(); set_screen_page(1); printf("\nAuf der 2. Seite !\n"); getchar(); set_screen_page(0); set_cur(0,0); printf("\nWieder auf der 1. Seite !\n"); getchar(); cls(); return 0; } */ /* BIO.H --> Enthaelt die Prototypen der BIOS-Funktionen. */ /* --- Funktionen in VIDEO.C --- */ extern void scroll_up(int anzahl, int anf_zeile,int end_zeile); extern void scroll_down(int anzahl, int anf_zeile, int end_zeile); extern void set_cur(int zeile, int spalte); extern void get_cur(int *zeile, int *spalte); extern void cls(void); extern int get_screen_page(void); extern void set_screen_page(int page); /* --- Funktionen in GETCB.C / PUTCB.C --- */ extern int getcb(void); extern void putcb(int c); extern void putcb9(int c, unsigned count, unsigned modus); extern void balken(int zeile, int spalte, int laenge, int c, unsigned modus); extern int input(char *puffer, int max,... ); need your help, can't find my mistakes:((

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  • PHP: POST Request to ASP.NET website results in 500 server error when html tags included

    - by RyanJD
    My situation: I need to send text to an ASP.NET web service using POST. The entire page there is a form: <form name="aspnetForm" method="post" action="Discussion.aspx?classroom=lG39il1cotOAGJwiNvmQlIPfwmjikD%2fAHLhjjGInAZQ%3d&amp;Page=Posts&amp;ID=794239&amp;Sort=&amp;SortOrder=" id="aspnetForm"> So, I figured if I sent a POST request to this form with the correct inputs it would work. And, to an extent, it has. The form inputs are as follows: <input type="hidden" name="__EVENTTARGET" id="__EVENTTARGET" value="" /> <input type="hidden" name="__EVENTARGUMENT" id="__EVENTARGUMENT" value="" /> <input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDw..." /> <input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="/wEWYQLrt..." /> And a bunch of other inputs. The code I have used is as follows: // grab form info $inputs = extract_form_inputs($discussion['body']); $inputs['__EVENTTARGET'] = 'ctl00$cphMain$ctl01$btnSubmit'; $inputs['ctl00$cphMain$ctl01$tbNickname'] = "Your Instructor"; $inputs['ctl00$cphMain$ctl01$reMessage'] = $message; // submit form $r = request_send($discussion['url'], $inputs); extract_form_inputs does exactly that. $discussion['body'] is the content of the page. $discussion['url'] is the URL of the page. request_send has two arguments: ($url, $post_array). It performs rawurlencode on each element of the array and joins them up as keypairs, in the same way as http_build_query. The request is url encoded properly, sent to the correct page, and works fine until I insert html tags. I have checked - the 'greater than' and 'less than' symbols ('<' and '') are url-encoded properly. However, the server responds with a 500 error. It accepts any other text. Has anyone else come across this sort of problem? Is there some setting on an ASP.NET server that denies html? I can't see this being the case - there is a rich text editor on the website that I am sending requests to. This text editor performs the same request as I am, only I am doing it remotely. The rich text editor sends html to the form - I have checked that, too, using javascript. Note: I do not have the power to modify the ASP.NET server.

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  • How to maximize http.sys file upload performance

    - by anelson
    I'm building a tool that transfers very large streaming data sets (possibly on the order of terabytes in a single stream; routinely in the tens of gigabytes) from one server to another. The client portion of the tool will read blocks from the source disk, and send them over the network. The server side will read these blocks off the network and write them to a file on the server disk. Right now I'm trying to decide which transport to use. Options are raw TCP, and HTTP. I really, REALLY want to be able to use HTTP. The HttpListener (or WCF if I want to go that route) make it easy to plug in to the HTTP Server API (http.sys), and I can get things like authentication and SSL for free. The problem right now is performance. I wrote a simple test harness that sends 128K blocks of NULL bytes using the BeginWrite/EndWrite async I/O idiom, with async BeginRead/EndRead on the server side. I've modified this test harness so I can do this with either HTTP PUT operations via HttpWebRequest/HttpListener, or plain old socket writes using TcpClient/TcpListener. To rule out issues with network cards or network pathways, both the client and server are on one machine and communicate over localhost. On my 12-core Windows 2008 R2 test server, the TCP version of this test harness can push bytes at 450MB/s, with minimal CPU usage. On the same box, the HTTP version of the test harness runs between 130MB/s and 200MB/s depending upon how I tweak it. In both cases CPU usage is low, and the vast majority of what CPU usage there is is kernel time, so I'm pretty sure my usage of C# and the .NET runtime is not the bottleneck. The box has two 6-core Xeon X5650 processors, 24GB of single-ranked DDR3 RAM, and is used exclusively by me for my own performance testing. I already know about HTTP client tweaks like ServicePointManager.MaxServicePointIdleTime, ServicePointManager.DefaultConnectionLimit, ServicePointManager.Expect100Continue, and HttpWebRequest.AllowWriteStreamBuffering. Does anyone have any ideas for how I can get HTTP.sys performance beyond 200MB/s? Has anyone seen it perform this well on any environment?

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  • Really "wow" them in the interview

    - by Juliet
    Let me put it to you this way: I'm a top-notch programmer, but a notoriously bad interviewee. I've flunked 3 interviews consecutively because I get so nervous that my voice tightens at least 2 octaves higher and I start visibly shaking -- mind you, I can handle whatever technical questions the interviewer throws at me in that state, but I think it looks bad to come off as a quivering, squeaky-voiced young woman during a job interview. I've just got the personality type of a shy computer programmer. No matter how technical I am, I'm going to get passed up in favor of a smooth talker. I have another interview coming up shortly, and I want to really impress the company. Here are my trouble spots: What can I do to be less nervous during my interview? I always get really excited when I hear I have a face-to-face interview, but get more and more anxious as D-Day the interview approaches. My employers wants me to explain what I used to do at my prior employment. I'm a very chatty person and tend to talk/squeak for 10 minutes at a time. How long or short should I time my answers? On that note, when I'm explaining what I did at prior jobs, what exactly is my interviewer looking for? At some point, my interviewer will ask "do you have any questions for me while you're here?" I should, but what kinds of questions should I ask to show that I'm interested in being employed? My interviewer always asks why I'm looking for a new job. The real reason is that my present salary is $27K/yr [Edit to add: and I've yet to get a raise since I started], and I want to make more money -- otherwise the work environment is fine. How do I sugarcoat "I want to make more money" into something that sounds nicer? I have only one prior programmer job, and I've worked there for 18 months, but I have the skill of someone with 4 to 6 years of experience. What can I say to compete against applicants with more work experience? I took a low-paying $27K/yr programming job just to get my foot in IT, and I've been trying to leverage that job as a stepping stone to better opportunities. I get interviews because I consistently out-score senior-level developers in aptitude tests, and my desired salary range is right in the ballpark of what most companies want to offer. Unfortunately, while I've been a programming as a hobby for 10 years and I'm geared to graduate with my BA in Comp Sci in May '09, employers see me as a junior-level programmer with no degree. I want to prove them wrong and get a job that matches my skill level. I'd appreciate any advice anyone has to offer, especially if they can help me get a better job in the process.

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  • Convert a PDF to a Transparent PNG with GhostScript

    - by Jonathon Wolfe
    Hi all. I am attempting, unsuccessfully, to use Ghostscript to rasterize PDF files with a transparent background to PNG files with a transparent background. I've searched high and low for questions from others attempting the same thing and none of the posted solutions, which as far as I can tell come down to specifying -sDEVICE=pngalpha, have worked with my test files. At this point I would really appreciate any advice or tips a more experienced hand could provide. My test PDF is located here: http://www.kolossus.com/files/test.pdf It could be that the issue is with this file, but I doubt it. As far as I can tell, it has no specified background, and when I open the file with a transparency-aware app like Photoshop or Illustrator, sure enough it displays with a transparent background. However, when opened with an application like Adobe Reader the file is rendered with a white background. I believe that this has more to do with the application rendering the PDF than with the PDF itself -- apps like Adobe Reader assume you want to see what a printed document will look like and therefore always show a white canvas behind the artwork -- but I can't be sure. The gs command I'm using is: gs -dNOPAUSE -dBATCH -sDEVICE=pngalpha -r72 -sOutputFile=test.png test.pdf This produces a PNG that has transparent pixels outside of the bounding box of the artwork in the file, but all pixels that are inside the artwork's bounding box are rasterized against a white background. This is a problem for me, as my artwork has drop shadows and antialiased edges that need to be preserved in the final output, and can't just be postprocessed out with ImageMagick. A sample of my PNG output is at the same location as the pdf above, with .png at the end (stackoverflow won't let me include more than one url in my post). Interestingly, I see no effects from using the -dBackgroundColor flag, even if I set it to something non-white like -dBackgroundColor=16#ff0000. Perhaps my understanding of the syntax of this flag is wrong. Also interestingly, I see no effects from using the -dTextAlphaBits=4 -dGraphicsAlphaBits=4 flags to try to enable subpixel antialiasing. I would also appreciate any advice on how to enable subpixel antialiasing, especially on text. Finally, I'm using GPL Ghostscript 8.64 on Mac OS 10.5.7, and the rendering workflow I'm trying to get set up is to generate transparent PNG images from PDFs output by PrinceXML. I'm calling Ghostscript directly for the rasterization instead of using ImageMagick because ImageMagick delegates to Ghostscript for PDF rasterization and I should be able to control the rasterization better by calling GS directly. Thanks for your help. -Jon Wolfe

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  • With sqlalchemy how to dynamically bind to database engine on a per-request basis

    - by Peter Hansen
    I have a Pylons-based web application which connects via Sqlalchemy (v0.5) to a Postgres database. For security, rather than follow the typical pattern of simple web apps (as seen in just about all tutorials), I'm not using a generic Postgres user (e.g. "webapp") but am requiring that users enter their own Postgres userid and password, and am using that to establish the connection. That means we get the full benefit of Postgres security. Complicating things still further, there are two separate databases to connect to. Although they're currently in the same Postgres cluster, they need to be able to move to separate hosts at a later date. We're using sqlalchemy's declarative package, though I can't see that this has any bearing on the matter. Most examples of sqlalchemy show trivial approaches such as setting up the Metadata once, at application startup, with a generic database userid and password, which is used through the web application. This is usually done with Metadata.bind = create_engine(), sometimes even at module-level in the database model files. My question is, how can we defer establishing the connections until the user has logged in, and then (of course) re-use those connections, or re-establish them using the same credentials, for each subsequent request. We have this working -- we think -- but I'm not only not certain of the safety of it, I also think it looks incredibly heavy-weight for the situation. Inside the __call__ method of the BaseController we retrieve the userid and password from the web session, call sqlalchemy create_engine() once for each database, then call a routine which calls Session.bind_mapper() repeatedly, once for each table that may be referenced on each of those connections, even though any given request usually references only one or two tables. It looks something like this: # in lib/base.py on the BaseController class def __call__(self, environ, start_response): # note: web session contains {'username': XXX, 'password': YYY} url1 = 'postgres://%(username)s:%(password)s@server1/finance' % session url2 = 'postgres://%(username)s:%(password)s@server2/staff' % session finance = create_engine(url1) staff = create_engine(url2) db_configure(staff, finance) # see below ... etc # in another file Session = scoped_session(sessionmaker()) def db_configure(staff, finance): s = Session() from db.finance import Employee, Customer, Invoice for c in [ Employee, Customer, Invoice, ]: s.bind_mapper(c, finance) from db.staff import Project, Hour for c in [ Project, Hour, ]: s.bind_mapper(c, staff) s.close() # prevents leaking connections between sessions? So the create_engine() calls occur on every request... I can see that being needed, and the Connection Pool probably caches them and does things sensibly. But calling Session.bind_mapper() once for each table, on every request? Seems like there has to be a better way. Obviously, since a desire for strong security underlies all this, we don't want any chance that a connection established for a high-security user will inadvertently be used in a later request by a low-security user.

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  • AVFoundation buffer comparison to a saved image

    - by user577552
    Hi, I am a long time reader, first time poster on StackOverflow, and must say it has been a great source of knowledge for me. I am trying to get to know the AVFoundation framework. What I want to do is save what the camera sees and then detect when something changes. Here is the part where I save the image to a UIImage : if (shouldSetBackgroundImage) { CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); // Create a bitmap graphics context with the sample buffer data CGContextRef context = CGBitmapContextCreate(rowBase, bufferWidth, bufferHeight, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst); // Create a Quartz image from the pixel data in the bitmap graphics context CGImageRef quartzImage = CGBitmapContextCreateImage(context); // Free up the context and color space CGContextRelease(context); CGColorSpaceRelease(colorSpace); // Create an image object from the Quartz image UIImage * image = [UIImage imageWithCGImage:quartzImage]; [self setBackgroundImage:image]; NSLog(@"reference image actually set"); // Release the Quartz image CGImageRelease(quartzImage); //Signal that the image has been saved shouldSetBackgroundImage = NO; } and here is the part where I check if there is any change in the image seen by the camera : else { CGImageRef cgImage = [backgroundImage CGImage]; CGDataProviderRef provider = CGImageGetDataProvider(cgImage); CFDataRef bitmapData = CGDataProviderCopyData(provider); char* data = CFDataGetBytePtr(bitmapData); if (data != NULL) { int64_t numDiffer = 0, pixelCount = 0; NSMutableArray * pointsMutable = [NSMutableArray array]; for( int row = 0; row < bufferHeight; row += 8 ) { for( int column = 0; column < bufferWidth; column += 8 ) { //we get one pixel from each source (buffer and saved image) unsigned char *pixel = rowBase + (row * bytesPerRow) + (column * BYTES_PER_PIXEL); unsigned char *referencePixel = data + (row * bytesPerRow) + (column * BYTES_PER_PIXEL); pixelCount++; if ( !match(pixel, referencePixel, matchThreshold) ) { numDiffer++; [pointsMutable addObject:[NSValue valueWithCGPoint:CGPointMake(SCREEN_WIDTH - (column/ (float) bufferHeight)* SCREEN_WIDTH - 4.0, (row/ (float) bufferWidth)* SCREEN_HEIGHT- 4.0)]]; } } } numberOfPixelsThatDiffer = numDiffer; points = [pointsMutable copy]; } For some reason, this doesn't work, meaning that the iPhone detects almost everything as being different from the saved image, even though I set a very low threshold for detection in the match function... Do you have any idea of what I am doing wrong?

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  • jQuery: How can select clicked element in table without define unique id for each element

    - by Yosef
    Hello, I have table (that generated by server) below. I want to get input element value class="itemQuantity" of clicked row. I write jQuery code but he missing "this" of clicked element. <script type="text/javascript"> $(document).ready(function() { $('.updateButton').click(function() { alert($('.itemQuantity').val()); }); }); </script> How can I do it with jQuery (I thinking to use this and not create id for each element, but I have low knowledge in jQuery). Thanks, Yosef <table id="items"> <tr> <th>item id</th> <th>item name</th> <th>item quantity</th> <th>item update</th> </tr> <tr> <td class="itemID"> 1 </td> <td class="itemName"> Ferari </td> <td > <input class="itemQuantity" type="text" size="4" /> </td> <td> <button class="updateButton">update item</button> </td> </tr> <tr> <td class="itemID"> 2 </td> <td class="itemName"> Fiat </td> <td > <input class="itemQuantity" type="text" size="4" /> </td> <td> <button class="updateButton">update item</button> </td> </tr> <tr> <td class="itemID"> 3 </td> <td class="itemName"> Hundai </td> <td > <input class="itemQuantity" type="text" size="4" /> </td> <td> <button class="updateButton">update item</button> </td> </tr> </table>

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  • Jquery:: How can select clicked element in table without define unique id for each element

    - by Yosef
    Hello, I have table (that generated by server) below. I want to get input element value class="itemQuantity" of clicked row. I write Jquery code but he missing "this" of clicked element. <script type="text/javascript"> $(document).ready(function() { $('.updateButton').click(function() { alert($('.itemQuantity').val()); }); }); </script> How Can I do it with jquery(I thinking to use this and not create id for each element, but I have low knoledge in jquery). Thanks, Yosef <table id="items"> <tr> <th>item id</th> <th>item name</th> <th>item quantity</th> <th>item update</th> </tr> <tr> <td class="itemID"> 1 </td> <td class="itemName"> Ferari </td> <td > <input class="itemQuantity" type="text" size="4"/> </td> <td> <button class="updateButton" >update item</button> </td> </tr> <tr> <td class="itemID"> 2 </td> <td class="itemName"> Fiat </td> <td > <input class="itemQuantity" type="text" size="4"/> </td> <td> <button class="updateButton" >update item</button> </td> </tr> <tr> <td class="itemID"> 3 </td> <td class="itemName"> Hundai </td> <td > <input class="itemQuantity" type="text" size="4"/> </td> <td> <button class="updateButton" >update item</button> </td> </tr> </table>

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  • Why is Oracle using a skip scan for this query?

    - by Jason Baker
    Here's the tkprof output for a query that's running extremely slowly (WARNING: it's long :-) ): SELECT mbr_comment_idn, mbr_crt_dt, mbr_data_source, mbr_dol_bl_rmo_ind, mbr_dxcg_ctl_member, mbr_employment_start_dt, mbr_employment_term_dt, mbr_entity_active, mbr_ethnicity_idn, mbr_general_health_status_code, mbr_hand_dominant_code, mbr_hgt_feet, mbr_hgt_inches, mbr_highest_edu_level, mbr_insd_addr_idn, mbr_insd_alt_id, mbr_insd_name, mbr_insd_ssn_tin, mbr_is_smoker, mbr_is_vip, mbr_lmbr_first_name, mbr_lmbr_last_name, mbr_marital_status_cd, mbr_mbr_birth_dt, mbr_mbr_death_dt, mbr_mbr_expired, mbr_mbr_first_name, mbr_mbr_gender_cd, mbr_mbr_idn, mbr_mbr_ins_type, mbr_mbr_isreadonly, mbr_mbr_last_name, mbr_mbr_middle_name, mbr_mbr_name, mbr_mbr_status_idn, mbr_mpi_id, mbr_preferred_am_pm, mbr_preferred_time, mbr_prv_innetwork, mbr_rep_addr_idn, mbr_rep_name, mbr_rp_mbr_id, mbr_same_mbr_ins, mbr_special_needs_cd, mbr_timezone, mbr_upd_dt, mbr_user_idn, mbr_wgt, mbr_work_status_idn FROM (SELECT /*+ FIRST_ROWS(1) */ mbr_comment_idn, mbr_crt_dt, mbr_data_source, mbr_dol_bl_rmo_ind, mbr_dxcg_ctl_member, mbr_employment_start_dt, mbr_employment_term_dt, mbr_entity_active, mbr_ethnicity_idn, mbr_general_health_status_code, mbr_hand_dominant_code, mbr_hgt_feet, mbr_hgt_inches, mbr_highest_edu_level, mbr_insd_addr_idn, mbr_insd_alt_id, mbr_insd_name, mbr_insd_ssn_tin, mbr_is_smoker, mbr_is_vip, mbr_lmbr_first_name, mbr_lmbr_last_name, mbr_marital_status_cd, mbr_mbr_birth_dt, mbr_mbr_death_dt, mbr_mbr_expired, mbr_mbr_first_name, mbr_mbr_gender_cd, mbr_mbr_idn, mbr_mbr_ins_type, mbr_mbr_isreadonly, mbr_mbr_last_name, mbr_mbr_middle_name, mbr_mbr_name, mbr_mbr_status_idn, mbr_mpi_id, mbr_preferred_am_pm, mbr_preferred_time, mbr_prv_innetwork, mbr_rep_addr_idn, mbr_rep_name, mbr_rp_mbr_id, mbr_same_mbr_ins, mbr_special_needs_cd, mbr_timezone, mbr_upd_dt, mbr_user_idn, mbr_wgt, mbr_work_status_idn, ROWNUM AS ora_rn FROM (SELECT mbr.comment_idn AS mbr_comment_idn, mbr.crt_dt AS mbr_crt_dt, mbr.data_source AS mbr_data_source, mbr.dol_bl_rmo_ind AS mbr_dol_bl_rmo_ind, mbr.dxcg_ctl_member AS mbr_dxcg_ctl_member, mbr.employment_start_dt AS mbr_employment_start_dt, mbr.employment_term_dt AS mbr_employment_term_dt, mbr.entity_active AS mbr_entity_active, mbr.ethnicity_idn AS mbr_ethnicity_idn, mbr.general_health_status_code AS mbr_general_health_status_code, mbr.hand_dominant_code AS mbr_hand_dominant_code, mbr.hgt_feet AS mbr_hgt_feet, mbr.hgt_inches AS mbr_hgt_inches, mbr.highest_edu_level AS mbr_highest_edu_level, mbr.insd_addr_idn AS mbr_insd_addr_idn, mbr.insd_alt_id AS mbr_insd_alt_id, mbr.insd_name AS mbr_insd_name, mbr.insd_ssn_tin AS mbr_insd_ssn_tin, mbr.is_smoker AS mbr_is_smoker, mbr.is_vip AS mbr_is_vip, mbr.lmbr_first_name AS mbr_lmbr_first_name, mbr.lmbr_last_name AS mbr_lmbr_last_name, mbr.marital_status_cd AS mbr_marital_status_cd, mbr.mbr_birth_dt AS mbr_mbr_birth_dt, mbr.mbr_death_dt AS mbr_mbr_death_dt, mbr.mbr_expired AS mbr_mbr_expired, mbr.mbr_first_name AS mbr_mbr_first_name, mbr.mbr_gender_cd AS mbr_mbr_gender_cd, mbr.mbr_idn AS mbr_mbr_idn, mbr.mbr_ins_type AS mbr_mbr_ins_type, mbr.mbr_isreadonly AS mbr_mbr_isreadonly, mbr.mbr_last_name AS mbr_mbr_last_name, mbr.mbr_middle_name AS mbr_mbr_middle_name, mbr.mbr_name AS mbr_mbr_name, mbr.mbr_status_idn AS mbr_mbr_status_idn, mbr.mpi_id AS mbr_mpi_id, mbr.preferred_am_pm AS mbr_preferred_am_pm, mbr.preferred_time AS mbr_preferred_time, mbr.prv_innetwork AS mbr_prv_innetwork, mbr.rep_addr_idn AS mbr_rep_addr_idn, mbr.rep_name AS mbr_rep_name, mbr.rp_mbr_id AS mbr_rp_mbr_id, mbr.same_mbr_ins AS mbr_same_mbr_ins, mbr.special_needs_cd AS mbr_special_needs_cd, mbr.timezone AS mbr_timezone, mbr.upd_dt AS mbr_upd_dt, mbr.user_idn AS mbr_user_idn, mbr.wgt AS mbr_wgt, mbr.work_status_idn AS mbr_work_status_idn FROM mbr JOIN mbr_identfn ON mbr.mbr_idn = mbr_identfn.mbr_idn WHERE mbr_identfn.mbr_idn = mbr.mbr_idn AND mbr_identfn.identfd_type = :identfd_type_1 AND mbr_identfn.identfd_number = :identfd_number_1 AND mbr_identfn.entity_active = :entity_active_1) WHERE ROWNUM <= :ROWNUM_1) WHERE ora_rn > :ora_rn_1 call count cpu elapsed disk query current rows ------- ------ -------- ---------- ---------- ---------- ---------- ---------- Parse 9936 0.46 0.49 0 0 0 0 Execute 9936 0.60 0.59 0 0 0 0 Fetch 9936 329.87 404.00 0 136966922 0 0 ------- ------ -------- ---------- ---------- ---------- ---------- ---------- total 29808 330.94 405.09 0 136966922 0 0 Misses in library cache during parse: 0 Optimizer mode: FIRST_ROWS Parsing user id: 36 (JIVA_DEV) Rows Row Source Operation ------- --------------------------------------------------- 0 VIEW (cr=102 pr=0 pw=0 time=2180 us) 0 COUNT STOPKEY (cr=102 pr=0 pw=0 time=2163 us) 0 NESTED LOOPS (cr=102 pr=0 pw=0 time=2152 us) 0 INDEX SKIP SCAN IDX_MBR_IDENTFN (cr=102 pr=0 pw=0 time=2140 us)(object id 341053) 0 TABLE ACCESS BY INDEX ROWID MBR (cr=0 pr=0 pw=0 time=0 us) 0 INDEX UNIQUE SCAN PK_CLAIMANT (cr=0 pr=0 pw=0 time=0 us)(object id 334044) Rows Execution Plan ------- --------------------------------------------------- 0 SELECT STATEMENT MODE: HINT: FIRST_ROWS 0 VIEW 0 COUNT (STOPKEY) 0 NESTED LOOPS 0 INDEX MODE: ANALYZED (SKIP SCAN) OF 'IDX_MBR_IDENTFN' (INDEX (UNIQUE)) 0 TABLE ACCESS MODE: ANALYZED (BY INDEX ROWID) OF 'MBR' (TABLE) 0 INDEX MODE: ANALYZED (UNIQUE SCAN) OF 'PK_CLAIMANT' (INDEX (UNIQUE)) ******************************************************************************** Based on my reading of Oracle's documentation of skip scans, a skip scan is most useful when the first column of an index has a low number of unique values. The thing is that the first index of this column is a unique primary key. So am I correct in assuming that a skip scan is the wrong thing to do here? Also, what kind of scan should it be doing? Should I do some more hinting for this query? EDIT: I should also point out that the query's where clause uses the columns in IDX_MBR_IDENTFN and no columns other than what's in that index. So as far as I can tell, I'm not skipping any columns.

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  • Publishing WCF .NET 3.5 to IIS 6 (Windows Server 2003)

    - by Adam
    I've been developing a WCF web service using .NET 3.5 with IIS7 and it works perfectly on my local computer. I tried publishing it to a server running IIS 6 and even though I can view the WSDL in my browser, the client application doesn't seem to be connecting to it correctly. I launched a packet sniffing app (Charles Proxy) and the response for the first message comes back to the client empty (0 bytes). Every message after the first one times out. The WCF service is part of a larger application that uses ASP .NET 3.5. That application has been working fine on IIS 6 for awhile now so I think it's something specific to WCF. I also tried throwing an exception in the SVC file to see if it made it that far and the exception never got thrown so I have a feeling it's something more low level that's not working. Any thoughts? Is there anything I need to install on the IIS5 server? If so how am I still able to view the WSDL in my browser? The service is being consumed via an SVC file using basicHttpBinding Here's the meat of the Web.Config (let me know if you need any other part of it): <system.net> <defaultProxy> <proxy usesystemdefault="False" proxyaddress="http://127.0.0.1:80" bypassonlocal="True"/> </defaultProxy> </system.net> ... <system.serviceModel> <services> <service name="Nexternal.Service.XMLTools.VNService" behaviorConfiguration="VNServiceBehavior"> <!--The first endpoint would be picked up from the confirg this shows how the config can be overriden with the service host--> <endpoint address="" binding="basicHttpBinding" contract="Nexternal.Service.XMLTools.IVNService" /> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" name="mexHttpBinding" /> </service> </services> <behaviors> <serviceBehaviors> <behavior name="VNServiceBehavior"> <serviceMetadata httpGetEnabled="true" /> <serviceDebug includeExceptionDetailInFaults="true" /> </behavior> </serviceBehaviors> </behaviors> <serviceHostingEnvironment aspNetCompatibilityEnabled="true" /> </system.serviceModel>

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  • Any software for pattern-matching and -rewriting source code?

    - by Steven A. Lowe
    I have some old software (in a language that's not dead but is dead to me ;-)) that implements a basic pattern-matching and -rewriting system for source code. I am considering resurrecting this code, translating it into a modern language, and open-sourcing the project as a refactoring power-tool. Before I go much further, I want to know if anything like this exists already (my google-fu is fanning air on this tonight). Here's how it works: the pattern-matching part matches source-code patterns spanning multiple lines of code using a template with binding variables, the pattern-rewriting part uses a template to rewrite the matched code, inserting the contents of the bound variables from the matching template matching and rewriting templates are associated (1:1) by a simple (unconditional) rewrite rule the software operates on the abstract syntax tree (AST) of the input application, and outputs a modified AST which can then be regenerated into new source code for example, suppose we find a bunch of while-loops that really should be for-loops. The following template will match the while-loop pattern: Template oldLoopPtrn int @cnt@ = 0; while (@cnt@ < @max@) { … @body@ ++@cnt@; } End_Template while the following template will specify the output rewrite pattern: Template newLoopPtrn for(int @cnt@ = 0; @cnt@ < @max@; @cnt@++) { @body@ } End_Template and a simple rule to associate them Rule oldLoopPtrn --> newLoopPtrn so code that looks like this int i=0; while(i<arrlen) { printf("element %d: %f\n",i,arr[i]); ++i; } gets automatically rewritten to look like this for(int i = 0; i < arrlen; i++) { printf("element %d: %f\n",i,arr[i]); } The closest thing I've seen like this is some of the code-refactoring tools, but they seem to be geared towards interactive rewriting of selected snippets, not wholesale automated changes. I believe that this kind of tool could supercharge refactoring, and would work on multiple languages (even HTML/CSS). I also believe that converting and polishing the code base would be a huge project that I simply cannot do alone in any reasonable amount of time. So, anything like this out there already? If not, any obvious features (besides rewrite-rule conditions) to consider? EDIT: The one feature of this system that I like very much is that the template patterns are fairly obvious and easy to read because they're written in the same language as the target source code, not in some esoteric mutated regex/BNF format.

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  • Why does one loop take longer to detect a shared memory update than another loop?

    - by Joseph Garvin
    I've written a 'server' program that writes to shared memory, and a client program that reads from the memory. The server has different 'channels' that it can be writing to, which are just different linked lists that it's appending items too. The client is interested in some of the linked lists, and wants to read every node that's added to those lists as it comes in, with the minimum latency possible. I have 2 approaches for the client: For each linked list, the client keeps a 'bookmark' pointer to keep its place within the linked list. It round robins the linked lists, iterating through all of them over and over (it loops forever), moving each bookmark one node forward each time if it can. Whether it can is determined by the value of a 'next' member of the node. If it's non-null, then jumping to the next node is safe (the server switches it from null to non-null atomically). This approach works OK, but if there are a lot of lists to iterate over, and only a few of them are receiving updates, the latency gets bad. The server gives each list a unique ID. Each time the server appends an item to a list, it also appends the ID number of the list to a master 'update list'. The client only keeps one bookmark, a bookmark into the update list. It endlessly checks if the bookmark's next pointer is non-null ( while(node->next_ == NULL) {} ), if so moves ahead, reads the ID given, and then processes the new node on the linked list that has that ID. This, in theory, should handle large numbers of lists much better, because the client doesn't have to iterate over all of them each time. When I benchmarked the latency of both approaches (using gettimeofday), to my surprise #2 was terrible. The first approach, for a small number of linked lists, would often be under 20us of latency. The second approach would have small spats of low latencies but often be between 4,000-7,000us! Through inserting gettimeofday's here and there, I've determined that all of the added latency in approach #2 is spent in the loop repeatedly checking if the next pointer is non-null. This is puzzling to me; it's as if the change in one process is taking longer to 'publish' to the second process with the second approach. I assume there's some sort of cache interaction going on I don't understand. What's going on?

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  • Is it normal for a programmer with 2 years experience to take a long time to code simple programs?

    - by ajax81
    Hi all, I'm a relatively new programmer (18 months on the scene), and I'm finally getting to the point where I'm comfortable accepting projects and developing solutions under minimal supervision. Unfortunately, this also means that I've become acutely aware of my performance shortfalls, the most prevalent of which is the amount of time it takes me to develop, test, and submit algorithms for review. A great example of what I'm talking about occurred this week when I was tasked with developing a simple XML web service (asp.net 3.5) callable via client-side JavaScript, that accepts a single parameter and returns a dataset output to a modal window (please note this is the first time I've had to develop a web service and have had ZERO experience creating/consuming them...let alone calling them from JS client side). Keeping a long story short -- I worked on it for 4 days straight, all day each day, for a grand total of 36 hours, not including the time I spent dwelling on the problem in the shower, the morning commute, and laying awake in bed at night. I learned a great deal about web services and xml/json/javascript...but was called in for a management review to discuss the length of time it took me to develop the solution. In the meeting, I was praised for the quality of my work and was in fact told that my effort was commendable. However, they (senior leads and pm's) weren't impressed with the amount of time it took me to develop the solution and expressed that they would have liked to see the solution in roughly 1/3 of the time it took me. I guess what concerns me the most is that I've identified this pattern as common for myself. Between online videos, book research, and trial/error coding...if its something I haven't seen before, I can spend up to two weeks on a problem that seems to only take the pros in the videos moments to code up. And of course, knowing that management isn't happy with this pattern has shaken me up a bit. To sum up, I have some very specific questions I'd like to ask, and would greatly appreciate your objective professional feedback. Is my experience as a junior programmer common among new developers? Or is it possible that I'm just not cut out for the work? If you suspect that my experience is not common and that there may be an aptitude issue, do you have any suggestions/solutions that I could propose to management to help bring me up to speed? Do seasoned, professional programmers ever encounter knowledge barriers that considerably delay deliverables? When you started out in the industry, did you know how to "do it all"? If not, how long did it take you to be perceived as "proficient"? Was it a natural progression of trial and error, or was there a particular zen moment when you knew you had achieved super saiyen power level? Anyways, thanks for taking the time to read my question(s). I don't know if this is the right place to ask for professional career guidance, but I greatly appreciate your willingness to help me out. Cheers, Daniel

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  • Should I use Python or Assembly for a super fast copy program

    - by PyNEwbie
    As a maintenance issue I need to routinely (3-5 times per year) copy a repository that is now has over 20 million files and exceeds 1.5 terabytes in total disk space. I am currently using RICHCOPY, but have tried others. RICHCOPY seems the fastest but I do not believe I am getting close to the limits of the capabilities of my XP machine. I am toying around with using what I have read in The Art of Assembly Language to write a program to copy my files. My other thought is to start learning how to multi-thread in Python to do the copies. I am toying around with the idea of doing this in Assembly because it seems interesting, but while my time is not incredibly precious it is precious enough that I am trying to get a sense of whether or not I will see significant enough gains in copy speed. I am assuming that I would but I only started really learning to program 18 months and it is still more or less a hobby. Thus I may be missing some fundamental concept of what happens with interpreted languages. Any observations or experiences would be appreciated. Note, I am not looking for any code. I have already written a basic copy program in Python 2.6 that is no slower than RICHCOPY. I am looking for some observations on which will give me more speed. Right now it takes me over 50 hours to make a copy from a disk to a Drobo and then back from the Drobo to a disk. I have a LogicCube for when I am simply duplicating a disk but sometimes I need to go from a disk to Drobo or the reverse. I am thinking that given that I can sector copy a 3/4 full 2 terabyte drive using the LogicCube in under seven hours I should be able to get close to that using Assembly, but I don't know enough to know if this is valid. (Yes, sometimes ignorance is bliss) The reason I need to speed it up is I have had two or three cycles where something has happened during copy (fifty hours is a long time to expect the world to hold still) that has caused me to have to trash the copy and start over. For example, last week the water main broke under our building and shorted out the power.

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  • What is a good dumbed-down, safe template system for PHP?

    - by Wilhelm
    (Summary: My users need to be able to edit the structure of their dynamically generated web pages without being able to do any damage.) Greetings, ladies and gentlemen. I am currently working on a service where customers from a specific demographic can create a specific type of web site and fill it with their own content. The system is written in PHP. Many of the users of this system wish to edit how their particular web site looks, or, more commonly, have a designer do it for them. Editing the CSS is fine and dandy, but sometimes that's not enough. Sometimes they want to shuffle the entire page structure around by editing the raw HTML of the dynamically created web pages. The templating system used by WordPress is, as far as I can see, perfect for my use. Except for one thing which is critically important. In addition to being able to edit how comments are displayed or where the menu goes, someone editing a template can have that template execute arbitrary PHP code. As the same codebase runs all these different sites, with all content in the same databse, allowing my users to run arbitrary code is clearly out of the question. So what I need, is a dumbed-down, idiot-proof templating system where my users can edit most of the page structure on their own, pulling in the dynamic sections wherever, without being able to even echo 1+1;. Observe the following psuedocode: <!DOCTYPE html> <title><!-- $title --></title> <!-- header() --> <!-- menu() --> <div>Some random custom crap added by the user.</div> <!-- page_content() --> That's the degree of power I'd like to grant my users. They don't need to do their own loops or calculations or anything. Just include my variables and functions and leave the rest to me. I'm sure I'm not the only person on the planet that needs something like this. Do you know of any ready-made templating systems I could use? Thanks in advance for your reply.

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