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  • Free memory outside function [migrated]

    - by Dev Bag
    Can you please help with this issue, is the below gonna leak memory or is it ok? and please let me know if there is something else that I need to pay attention to typedef struct { int len; UC * message; }pack; pack * prepare_packet_to_send(const int length,const unsigned char tag,const int numargs, ... ) { pack *layer= malloc(sizeof(pack)); va_list listp; va_start( listp, numargs ); int step = 0; layer->message = (unsigned char *) malloc(length); layer->len = length; int i = 0; int len = 0; unsigned char *source_message ; for( i = 0 ; i < numargs; i++ ) { source_message = va_arg( listp, unsigned char *); len = va_arg( listp, long); memcpy(layer->message+step, source_message, (long) len); step+=len; } va_end( listp ); return layer; } main() { pack *test = call prepare_packet_to_send(sizeof(var1)+sizeof(var2),any tag,any args) // are following two frees correct/enough? or is there something else i need to do to prevent mem leak? free(test->message); free(test); }

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  • What is the display list in Flash 10? Array? Linked list?

    - by Typeoneerror
    I'm working on a game that has many elements on stage, so I'm looking to optimize my loops. I know that Vector is faster than looping an array, but I'm also in some cases using: while (i < numChildren) getChildAt(i) ...to update sprites. My question is when I use getChildAt, is that accessing an Array or Vector or linked list or other? Should I instead store references to my objects in a Vector and loop through that instead?

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  • C++: Simplifying my program to convert numbers to from one base to another.

    - by Spin City
    Hello, I'm taking a beginner C++ course. I received an assignment telling me to write a program that converts an arbitrary number from any base between binary and hex to another base between binary and hex. I was asked to use separate functions to convert to and from base 10. It was to help us get used to using arrays. (We already covered passing by reference previously in class.) I already turned this in, but I'm pretty sure this wasn't how I was meant to do it: #include <iostream> #include <conio.h> #include <cstring> #include <cmath> using std::cout; using std::cin; using std::endl; int to_dec(char value[], int starting_base); char* from_dec(int value, int ending_base); int main() { char value[30]; int starting_base; int ending_base; cout << "This program converts from one base to another, so long as the bases are" << endl << "between 2 and 16." << endl << endl; input_numbers: cout << "Enter the number, then starting base, then ending base:" << endl; cin >> value >> starting_base >> ending_base; if (starting_base < 2 || starting_base > 16 || ending_base < 2 || ending_base > 16) { cout << "Invalid base(s). "; goto input_numbers; } for (int i=0; value[i]; i++) value[i] = toupper(value[i]); cout << "Base " << ending_base << ": " << from_dec(to_dec(value, starting_base), ending_base) << endl << "Press any key to exit."; getch(); return 0; } int to_dec(char value[], int starting_base) { char hex[16] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'}; long int return_value = 0; unsigned short int digit = 0; for (short int pos = strlen(value)-1; pos > -1; pos--) { for (int i=0; i<starting_base; i++) { if (hex[i] == value[pos]) { return_value+=i*pow((float)starting_base, digit++); break; } } } return return_value; } char* from_dec(int value, int ending_base) { char hex[16] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'}; char *return_value = (char *)malloc(30); unsigned short int digit = (int)ceil(log10((double)(value+1))/log10((double)ending_base)); return_value[digit] = 0; for (; value != 0; value/=ending_base) return_value[--digit] = hex[value%ending_base]; return return_value; } I'm pretty sure this is more advanced than it was meant to be. How do you think I was supposed to do it? I'm essentially looking for two kinds of answers: Examples of what a simple solution like the one my teacher probably expected would be. Suggestions on how to improve the code.

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  • Linked lists in Java - Help with writing methods

    - by user368241
    Representation of a string in linked lists In every intersection in the list there will be 3 fields : The letter itself. The number of times it appears consecutively. A pointer to the next intersection in the list. The following class CharNode represents a intersection in the list : public class CharNode { private char _data; private int _value; private charNode _next; public CharNode (char c, int val, charNode n) { _data = c; _value = val; _next = n; } public charNode getNext() { return _next; } public void setNext (charNode node) { _next = node; } public int getValue() { return _value; } public void setValue (int v) { value = v; } public char getData() { return _data; } public void setData (char c) { _data = c; } } The class StringList represents the whole list : public class StringList { private charNode _head; public StringList() { _head = null; } public StringList (CharNode node) { _head = node; } } Add methods to the class StringList according to the details : (I will add methods gradually according to my specific questions) (Pay attention, these are methods from the class String and we want to fulfill them by the representation of a string by a list as explained above) Pay attention to all the possible error cases. Write what is the time complexity and space complexity of every method that you wrote. Make sure the methods you wrote are effective. It is NOT allowed to use ready classes of Java. It is NOT allowed to move to string and use string operations. 1) public int indexOf (int ch) - returns the index in the string it is operated on of the first appeareance of the char "ch". If the char "ch" doesn't appear in the string, returns -1. If the value of fromIndex isn't in the range, returns -1. Here is my try : public int indexOf (int ch) { int count = 0; charNode pos = _head; if (pos == null ) { return -1; } for (pos = _head; pos!=null && pos.getData()!=ch; pos = pos.getNext()) { count = count + pos.getValue(); } if (pos==null) return -1; return count; } Time complexity = O(N) Space complexity = O(1) EDIT : I have a problem. I tested it in BlueJ and if the char ch doesn't appear it returns -1 but if it does, it always returns 0 and I don't understand why... I am confused. How can the compiler know that the value is the number of times the letter appears consecutively? Can I assume this because its given on the question or what? If it's true and I can assume this, then my code should be correct right? Ok I just spoke with my instructor and she said it isn't required to write it in the exercise but in order for me to test that it indeed works, I need to open a new class and write a code for making a list so that the the value of every node is the number of times the letter appears consecutively. Can someone please assist me? So I will copy+paste to BlueJ and this way I will be able to test all the methods. Meanwhile I am moving on to the next methods. 2) public int indexOf (int ch, int fromIndex) - returns the index in the string it is operated on of the first appeareance of the char "ch", as the search begins in the index "fromIndex". If the char "ch" doesn't appear in the string, returns -1. If the value of fromIndex doesn't appear in the range, returns -1. Here is my try: public int indexOf (int ch, int fromIndex) { int count = 0, len=0, i; charNode pos = _head; CharNode cur = _head; for (pos = _head; pos!=null; pos = pos.getNext()) { len = len+1; } if (fromIndex<0 || fromIndex>=len) return -1; for (i=0; i<fromIndex; i++) { cur = cur.getNext(); } if (cur == null ) { return -1; } for (cur = _head; cur!=null && cur.getData()!=ch; cur = cur.getNext()) { count = count + cur.getValue(); } if (cur==null) return -1; return count; } Time complexity = O(N) ? Space complexity = O(1) 3) public StringList concat (String str) - returns a string that consists of the string that it is operated on and in its end the string "str" is concatenated. Here is my try : public StringList concat (String str) { String str = ""; charNode pos = _head; if (str == null) return -1; for (pos = _head; pos!=null; pos = pos.getNext()) { str = str + pos.getData(); } str = str + "str"; return str; } Time complexity = O(N) Space complexity = O(1)

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  • MySQL Syslog Audit Plugin

    - by jonathonc
    This post shows the construction process of the Syslog Audit plugin that was presented at MySQL Connect 2012. It is based on an environment that has the appropriate development tools enabled including gcc,g++ and cmake. It also assumes you have downloaded the MySQL source code (5.5.16 or higher) and have compiled and installed the system into the /usr/local/mysql directory ready for use.  The information provided below is designed to show the different components that make up a plugin, and specifically an audit type plugin, and how it comes together to be used within the MySQL service. The MySQL Reference Manual contains information regarding the plugin API and how it can be used, so please refer there for more detailed information. The code in this post is designed to give the simplest information necessary, so handling every return code, managing race conditions etc is not part of this example code. Let's start by looking at the most basic implementation of our plugin code as seen below: /*    Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.    Author:  Jonathon Coombes    Licence: GPL    Description: An auditing plugin that logs to syslog and                 can adjust the loglevel via the system variables. */ #include <stdio.h> #include <string.h> #include <mysql/plugin_audit.h> #include <syslog.h> There is a commented header detailing copyright/licencing and meta-data information and then the include headers. The two important include statements for our plugin are the syslog.h plugin, which gives us the structures for syslog, and the plugin_audit.h include which has details regarding the audit specific plugin api. Note that we do not need to include the general plugin header plugin.h, as this is done within the plugin_audit.h file already. To implement our plugin within the current implementation we need to add it into our source code and compile. > cd /usr/local/src/mysql-5.5.28/plugin > mkdir audit_syslog > cd audit_syslog A simple CMakeLists.txt file is created to manage the plugin compilation: MYSQL_ADD_PLUGIN(audit_syslog audit_syslog.cc MODULE_ONLY) Run the cmake  command at the top level of the source and then you can compile the plugin using the 'make' command. This results in a compiled audit_syslog.so library, but currently it is not much use to MySQL as there is no level of api defined to communicate with the MySQL service. Now we need to define the general plugin structure that enables MySQL to recognise the library as a plugin and be able to install/uninstall it and have it show up in the system. The structure is defined in the plugin.h file in the MySQL source code.  /*   Plugin library descriptor */ mysql_declare_plugin(audit_syslog) {   MYSQL_AUDIT_PLUGIN,           /* plugin type                    */   &audit_syslog_descriptor,     /* descriptor handle               */   "audit_syslog",               /* plugin name                     */   "Author Name",                /* author                          */   "Simple Syslog Audit",        /* description                     */   PLUGIN_LICENSE_GPL,           /* licence                         */   audit_syslog_init,            /* init function     */   audit_syslog_deinit,          /* deinit function */   0x0001,                       /* plugin version                  */   NULL,                         /* status variables        */   NULL,                         /* system variables                */   NULL,                         /* no reserves                     */   0,                            /* no flags                        */ } mysql_declare_plugin_end; The general plugin descriptor above is standard for all plugin types in MySQL. The plugin type is defined along with the init/deinit functions and interface methods into the system for sharing information, and various other metadata information. The descriptors have an internally recognised version number so that plugins can be matched against the api on the running server. The other details are usually related to the type-specific methods and structures to implement the plugin. Each plugin has a type-specific descriptor as well which details how the plugin is implemented for the specific purpose of that plugin type. /*   Plugin type-specific descriptor */ static struct st_mysql_audit audit_syslog_descriptor= {   MYSQL_AUDIT_INTERFACE_VERSION,                        /* interface version    */   NULL,                                                 /* release_thd function */   audit_syslog_notify,                                  /* notify function      */   { (unsigned long) MYSQL_AUDIT_GENERAL_CLASSMASK |                     MYSQL_AUDIT_CONNECTION_CLASSMASK }  /* class mask           */ }; In this particular case, the release_thd function has not been defined as it is not required. The important method for auditing is the notify function which is activated when an event occurs on the system. The notify function is designed to activate on an event and the implementation will determine how it is handled. For the audit_syslog plugin, the use of the syslog feature sends all events to the syslog for recording. The class mask allows us to determine what type of events are being seen by the notify function. There are currently two major types of event: 1. General Events: This includes general logging, errors, status and result type events. This is the main one for tracking the queries and operations on the database. 2. Connection Events: This group is based around user logins. It monitors connections and disconnections, but also if somebody changes user while connected. With most audit plugins, the principle behind the plugin is to track changes to the system over time and counters can be an important part of this process. The next step is to define and initialise the counters that are used to track the events in the service. There are 3 counters defined in total for our plugin - the # of general events, the # of connection events and the total number of events.  static volatile int total_number_of_calls; /* Count MYSQL_AUDIT_GENERAL_CLASS event instances */ static volatile int number_of_calls_general; /* Count MYSQL_AUDIT_CONNECTION_CLASS event instances */ static volatile int number_of_calls_connection; The init and deinit functions for the plugin are there to be called when the plugin is activated and when it is terminated. These offer the best option to initialise the counters for our plugin: /*  Initialize the plugin at server start or plugin installation. */ static int audit_syslog_init(void *arg __attribute__((unused))) {     openlog("mysql_audit:",LOG_PID|LOG_PERROR|LOG_CONS,LOG_USER);     total_number_of_calls= 0;     number_of_calls_general= 0;     number_of_calls_connection= 0;     return(0); } The init function does a call to openlog to initialise the syslog functionality. The parameters are the service to log under ("mysql_audit" in this case), the syslog flags and the facility for the logging. Then each of the counters are initialised to zero and a success is returned. If the init function is not defined, it will return success by default. /*  Terminate the plugin at server shutdown or plugin deinstallation. */ static int audit_syslog_deinit(void *arg __attribute__((unused))) {     closelog();     return(0); } The deinit function will simply close our syslog connection and return success. Note that the syslog functionality is part of the glibc libraries and does not require any external factors.  The function names are what we define in the general plugin structure, so these have to match otherwise there will be errors. The next step is to implement the event notifier function that was defined in the type specific descriptor (audit_syslog_descriptor) which is audit_syslog_notify. /* Event notifier function */ static void audit_syslog_notify(MYSQL_THD thd __attribute__((unused)), unsigned int event_class, const void *event) { total_number_of_calls++; if (event_class == MYSQL_AUDIT_GENERAL_CLASS) { const struct mysql_event_general *event_general= (const struct mysql_event_general *) event; number_of_calls_general++; syslog(audit_loglevel,"%lu: User: %s Command: %s Query: %s\n", event_general->general_thread_id, event_general->general_user, event_general->general_command, event_general->general_query ); } else if (event_class == MYSQL_AUDIT_CONNECTION_CLASS) { const struct mysql_event_connection *event_connection= (const struct mysql_event_connection *) event; number_of_calls_connection++; syslog(audit_loglevel,"%lu: User: %s@%s[%s] Event: %d Status: %d\n", event_connection->thread_id, event_connection->user, event_connection->host, event_connection->ip, event_connection->event_subclass, event_connection->status ); } }   In the case of an event, the notifier function is called. The first step is to increment the total number of events that have occurred in our database.The event argument is then cast into the appropriate event structure depending on the class type, of general event or connection event. The event type counters are incremented and details are sent via the syslog() function out to the system log. There are going to be different line formats and information returned since the general events have different data compared to the connection events, even though some of the details overlap, for example, user, thread id, host etc. On compiling the code now, there should be no errors and the resulting audit_syslog.so can be loaded into the server and ready to use. Log into the server and type: mysql> INSTALL PLUGIN audit_syslog SONAME 'audit_syslog.so'; This will install the plugin and will start updating the syslog immediately. Note that the audit plugin attaches to the immediate thread and cannot be uninstalled while that thread is active. This means that you cannot run the UNISTALL command until you log into a different connection (thread) on the server. Once the plugin is loaded, the system log will show output such as the following: Oct  8 15:33:21 machine mysql_audit:[8337]: 87: User: root[root] @ localhost []  Command: (null)  Query: INSTALL PLUGIN audit_syslog SONAME 'audit_syslog.so' Oct  8 15:33:21 machine mysql_audit:[8337]: 87: User: root[root] @ localhost []  Command: Query  Query: INSTALL PLUGIN audit_syslog SONAME 'audit_syslog.so' Oct  8 15:33:40 machine mysql_audit:[8337]: 87: User: root[root] @ localhost []  Command: (null)  Query: show tables Oct  8 15:33:40 machine mysql_audit:[8337]: 87: User: root[root] @ localhost []  Command: Query  Query: show tables Oct  8 15:33:43 machine mysql_audit:[8337]: 87: User: root[root] @ localhost []  Command: (null)  Query: select * from t1 Oct  8 15:33:43 machine mysql_audit:[8337]: 87: User: root[root] @ localhost []  Command: Query  Query: select * from t1 It appears that two of each event is being shown, but in actuality, these are two separate event types - the result event and the status event. This could be refined further by changing the audit_syslog_notify function to handle the different event sub-types in a different manner.  So far, it seems that the logging is working with events showing up in the syslog output. The issue now is that the counters created earlier to track the number of events by type are not accessible when the plugin is being run. Instead there needs to be a way to expose the plugin specific information to the service and vice versa. This could be done via the information_schema plugin api, but for something as simple as counters, the obvious choice is the system status variables. This is done using the standard structure and the declaration: /*  Plugin status variables for SHOW STATUS */ static struct st_mysql_show_var audit_syslog_status[]= {   { "Audit_syslog_total_calls",     (char *) &total_number_of_calls,     SHOW_INT },   { "Audit_syslog_general_events",     (char *) &number_of_calls_general,     SHOW_INT },   { "Audit_syslog_connection_events",     (char *) &number_of_calls_connection,     SHOW_INT },   { 0, 0, SHOW_INT } };   The structure is simply the name that will be displaying in the mysql service, the address of the associated variables, and the data type being used for the counter. It is finished with a blank structure to show that there are no more variables. Remember that status variables may have the same name for variables from other plugin, so it is considered appropriate to add the plugin name at the start of the status variable name to avoid confusion. Looking at the status variables in the mysql client shows something like the following: mysql> show global status like "audit%"; +--------------------------------+-------+ | Variable_name                  | Value | +--------------------------------+-------+ | Audit_syslog_connection_events | 1     | | Audit_syslog_general_events    | 2     | | Audit_syslog_total_calls       | 3     | +--------------------------------+-------+ 3 rows in set (0.00 sec) The final connectivity piece for the plugin is to allow the interactive change of the logging level between the plugin and the system. This requires the ability to send changes via the mysql service through to the plugin. This is done using the system variables interface and defining a single variable to keep track of the active logging level for the facility. /* Plugin system variables for SHOW VARIABLES */ static MYSQL_SYSVAR_STR(loglevel, audit_loglevel,                         PLUGIN_VAR_RQCMDARG,                         "User can specify the log level for auditing",                         audit_loglevel_check, audit_loglevel_update, "LOG_NOTICE"); static struct st_mysql_sys_var* audit_syslog_sysvars[] = {     MYSQL_SYSVAR(loglevel),     NULL }; So now the system variable 'loglevel' is defined for the plugin and associated to the global variable 'audit_loglevel'. The check or validation function is defined to make sure that no garbage values are attempted in the update of the variable. The update function is used to save the new value to the variable. Note that the audit_syslog_sysvars structure is defined in the general plugin descriptor to associate the link between the plugin and the system and how much they interact. Next comes the implementation of the validation function and the update function for the system variable. It is worth noting that if you have a simple numeric such as integers for the variable types, the validate function is often not required as MySQL will handle the automatic check and validation of simple types. /* longest valid value */ #define MAX_LOGLEVEL_SIZE 100 /* hold the valid values */ static const char *possible_modes[]= { "LOG_ERROR", "LOG_WARNING", "LOG_NOTICE", NULL };  static int audit_loglevel_check(     THD*                        thd,    /*!< in: thread handle */     struct st_mysql_sys_var*    var,    /*!< in: pointer to system                                         variable */     void*                       save,   /*!< out: immediate result                                         for update function */     struct st_mysql_value*      value)  /*!< in: incoming string */ {     char buff[MAX_LOGLEVEL_SIZE];     const char *str;     const char **found;     int length;     length= sizeof(buff);     if (!(str= value->val_str(value, buff, &length)))         return 1;     /*         We need to return a pointer to a locally allocated value in "save".         Here we pick to search for the supplied value in an global array of         constant strings and return a pointer to one of them.         The other possiblity is to use the thd_alloc() function to allocate         a thread local buffer instead of the global constants.     */     for (found= possible_modes; *found; found++)     {         if (!strcmp(*found, str))         {             *(const char**)save= *found;             return 0;         }     }     return 1; } The validation function is simply to take the value being passed in via the SET GLOBAL VARIABLE command and check if it is one of the pre-defined values allowed  in our possible_values array. If it is found to be valid, then the value is assigned to the save variable ready for passing through to the update function. static void audit_loglevel_update(     THD*                        thd,        /*!< in: thread handle */     struct st_mysql_sys_var*    var,        /*!< in: system variable                                             being altered */     void*                       var_ptr,    /*!< out: pointer to                                             dynamic variable */     const void*                 save)       /*!< in: pointer to                                             temporary storage */ {     /* assign the new value so that the server can read it */     *(char **) var_ptr= *(char **) save;     /* assign the new value to the internal variable */     audit_loglevel= *(char **) save; } Since all the validation has been done already, the update function is quite simple for this plugin. The first part is to update the system variable pointer so that the server can read the value. The second part is to update our own global plugin variable for tracking the value. Notice that the save variable is passed in as a void type to allow handling of various data types, so it must be cast to the appropriate data type when assigning it to the variables. Looking at how the latest changes affect the usage of the plugin and the interaction within the server shows: mysql> show global variables like "audit%"; +-----------------------+------------+ | Variable_name         | Value      | +-----------------------+------------+ | audit_syslog_loglevel | LOG_NOTICE | +-----------------------+------------+ 1 row in set (0.00 sec) mysql> set global audit_syslog_loglevel="LOG_ERROR"; Query OK, 0 rows affected (0.00 sec) mysql> show global status like "audit%"; +--------------------------------+-------+ | Variable_name                  | Value | +--------------------------------+-------+ | Audit_syslog_connection_events | 1     | | Audit_syslog_general_events    | 11    | | Audit_syslog_total_calls       | 12    | +--------------------------------+-------+ 3 rows in set (0.00 sec) mysql> show global variables like "audit%"; +-----------------------+-----------+ | Variable_name         | Value     | +-----------------------+-----------+ | audit_syslog_loglevel | LOG_ERROR | +-----------------------+-----------+ 1 row in set (0.00 sec)   So now we have a plugin that will audit the events on the system and log the details to the system log. It allows for interaction to see the number of different events within the server details and provides a mechanism to change the logging level interactively via the standard system methods of the SET command. A more complex auditing plugin may have more detailed code, but each of the above areas is what will be involved and simply expanded on to add more functionality. With the above skeleton code, it is now possible to create your own audit plugins to implement your own auditing requirements. If, however, you are not of the coding persuasion, then you could always consider the option of the MySQL Enterprise Audit plugin that is available to purchase.

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  • SortedDictionary and SortedList

    - by Simon Cooper
    Apart from Dictionary<TKey, TValue>, there's two other dictionaries in the BCL - SortedDictionary<TKey, TValue> and SortedList<TKey, TValue>. On the face of it, these two classes do the same thing - provide an IDictionary<TKey, TValue> interface where the iterator returns the items sorted by the key. So what's the difference between them, and when should you use one rather than the other? (as in my previous post, I'll assume you have some basic algorithm & datastructure knowledge) SortedDictionary We'll first cover SortedDictionary. This is implemented as a special sort of binary tree called a red-black tree. Essentially, it's a binary tree that uses various constraints on how the nodes of the tree can be arranged to ensure the tree is always roughly balanced (for more gory algorithmical details, see the wikipedia link above). What I'm concerned about in this post is how the .NET SortedDictionary is actually implemented. In .NET 4, behind the scenes, the actual implementation of the tree is delegated to a SortedSet<KeyValuePair<TKey, TValue>>. One example tree might look like this: Each node in the above tree is stored as a separate SortedSet<T>.Node object (remember, in a SortedDictionary, T is instantiated to KeyValuePair<TKey, TValue>): class Node { public bool IsRed; public T Item; public SortedSet<T>.Node Left; public SortedSet<T>.Node Right; } The SortedSet only stores a reference to the root node; all the data in the tree is accessed by traversing the Left and Right node references until you reach the node you're looking for. Each individual node can be physically stored anywhere in memory; what's important is the relationship between the nodes. This is also why there is no constructor to SortedDictionary or SortedSet that takes an integer representing the capacity; there are no internal arrays that need to be created and resized. This may seen trivial, but it's an important distinction between SortedDictionary and SortedList that I'll cover later on. And that's pretty much it; it's a standard red-black tree. Plenty of webpages and datastructure books cover the algorithms behind the tree itself far better than I could. What's interesting is the comparions between SortedDictionary and SortedList, which I'll cover at the end. As a side point, SortedDictionary has existed in the BCL ever since .NET 2. That means that, all through .NET 2, 3, and 3.5, there has been a bona-fide sorted set class in the BCL (called TreeSet). However, it was internal, so it couldn't be used outside System.dll. Only in .NET 4 was this class exposed as SortedSet. SortedList Whereas SortedDictionary didn't use any backing arrays, SortedList does. It is implemented just as the name suggests; two arrays, one containing the keys, and one the values (I've just used random letters for the values): The items in the keys array are always guarenteed to be stored in sorted order, and the value corresponding to each key is stored in the same index as the key in the values array. In this example, the value for key item 5 is 'z', and for key item 8 is 'm'. Whenever an item is inserted or removed from the SortedList, a binary search is run on the keys array to find the correct index, then all the items in the arrays are shifted to accomodate the new or removed item. For example, if the key 3 was removed, a binary search would be run to find the array index the item was at, then everything above that index would be moved down by one: and then if the key/value pair {7, 'f'} was added, a binary search would be run on the keys to find the index to insert the new item, and everything above that index would be moved up to accomodate the new item: If another item was then added, both arrays would be resized (to a length of 10) before the new item was added to the arrays. As you can see, any insertions or removals in the middle of the list require a proportion of the array contents to be moved; an O(n) operation. However, if the insertion or removal is at the end of the array (ie the largest key), then it's only O(log n); the cost of the binary search to determine it does actually need to be added to the end (excluding the occasional O(n) cost of resizing the arrays to fit more items). As a side effect of using backing arrays, SortedList offers IList Keys and Values views that simply use the backing keys or values arrays, as well as various methods utilising the array index of stored items, which SortedDictionary does not (and cannot) offer. The Comparison So, when should you use one and not the other? Well, here's the important differences: Memory usage SortedDictionary and SortedList have got very different memory profiles. SortedDictionary... has a memory overhead of one object instance, a bool, and two references per item. On 64-bit systems, this adds up to ~40 bytes, not including the stored item and the reference to it from the Node object. stores the items in separate objects that can be spread all over the heap. This helps to keep memory fragmentation low, as the individual node objects can be allocated wherever there's a spare 60 bytes. In contrast, SortedList... has no additional overhead per item (only the reference to it in the array entries), however the backing arrays can be significantly larger than you need; every time the arrays are resized they double in size. That means that if you add 513 items to a SortedList, the backing arrays will each have a length of 1024. To conteract this, the TrimExcess method resizes the arrays back down to the actual size needed, or you can simply assign list.Capacity = list.Count. stores its items in a continuous block in memory. If the list stores thousands of items, this can cause significant problems with Large Object Heap memory fragmentation as the array resizes, which SortedDictionary doesn't have. Performance Operations on a SortedDictionary always have O(log n) performance, regardless of where in the collection you're adding or removing items. In contrast, SortedList has O(n) performance when you're altering the middle of the collection. If you're adding or removing from the end (ie the largest item), then performance is O(log n), same as SortedDictionary (in practice, it will likely be slightly faster, due to the array items all being in the same area in memory, also called locality of reference). So, when should you use one and not the other? As always with these sort of things, there are no hard-and-fast rules. But generally, if you: need to access items using their index within the collection are populating the dictionary all at once from sorted data aren't adding or removing keys once it's populated then use a SortedList. But if you: don't know how many items are going to be in the dictionary are populating the dictionary from random, unsorted data are adding & removing items randomly then use a SortedDictionary. The default (again, there's no definite rules on these sort of things!) should be to use SortedDictionary, unless there's a good reason to use SortedList, due to the bad performance of SortedList when altering the middle of the collection.

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  • RiverTrail - JavaScript GPPGU Data Parallelism

    - by JoshReuben
    Where is WebCL ? The Khronos WebCL working group is working on a JavaScript binding to the OpenCL standard so that HTML 5 compliant browsers can host GPGPU web apps – e.g. for image processing or physics for WebGL games - http://www.khronos.org/webcl/ . While Nokia & Samsung have some protype WebCL APIs, Intel has one-upped them with a higher level of abstraction: RiverTrail. Intro to RiverTrail Intel Labs JavaScript RiverTrail provides GPU accelerated SIMD data-parallelism in web applications via a familiar JavaScript programming paradigm. It extends JavaScript with simple deterministic data-parallel constructs that are translated at runtime into a low-level hardware abstraction layer. With its high-level JS API, programmers do not have to learn a new language or explicitly manage threads, orchestrate shared data synchronization or scheduling. It has been proposed as a draft specification to ECMA a (known as ECMA strawman). RiverTrail runs in all popular browsers (except I.E. of course). To get started, download a prebuilt version https://github.com/downloads/RiverTrail/RiverTrail/rivertrail-0.17.xpi , install Intel's OpenCL SDK http://www.intel.com/go/opencl and try out the interactive River Trail shell http://rivertrail.github.com/interactive For a video overview, see  http://www.youtube.com/watch?v=jueg6zB5XaM . ParallelArray the ParallelArray type is the central component of this API & is a JS object that contains ordered collections of scalars – i.e. multidimensional uniform arrays. A shape property describes the dimensionality and size– e.g. a 2D RGBA image will have shape [height, width, 4]. ParallelArrays are immutable & fluent – they are manipulated by invoking methods on them which produce new ParallelArray objects. ParallelArray supports several constructors over arrays, functions & even the canvas. // Create an empty Parallel Array var pa = new ParallelArray(); // pa0 = <>   // Create a ParallelArray out of a nested JS array. // Note that the inner arrays are also ParallelArrays var pa = new ParallelArray([ [0,1], [2,3], [4,5] ]); // pa1 = <<0,1>, <2,3>, <4.5>>   // Create a two-dimensional ParallelArray with shape [3, 2] using the comprehension constructor var pa = new ParallelArray([3, 2], function(iv){return iv[0] * iv[1];}); // pa7 = <<0,0>, <0,1>, <0,2>>   // Create a ParallelArray from canvas.  This creates a PA with shape [w, h, 4], var pa = new ParallelArray(canvas); // pa8 = CanvasPixelArray   ParallelArray exposes fluent API functions that take an elemental JS function for data manipulation: map, combine, scan, filter, and scatter that return a new ParallelArray. Other functions are scalar - reduce  returns a scalar value & get returns the value located at a given index. The onus is on the developer to ensure that the elemental function does not defeat data parallelization optimization (avoid global var manipulation, recursion). For reduce & scan, order is not guaranteed - the onus is on the dev to provide an elemental function that is commutative and associative so that scan will be deterministic – E.g. Sum is associative, but Avg is not. map Applies a provided elemental function to each element of the source array and stores the result in the corresponding position in the result array. The map method is shape preserving & index free - can not inspect neighboring values. // Adding one to each element. var source = new ParallelArray([1,2,3,4,5]); var plusOne = source.map(function inc(v) {     return v+1; }); //<2,3,4,5,6> combine Combine is similar to map, except an index is provided. This allows elemental functions to access elements from the source array relative to the one at the current index position. While the map method operates on the outermost dimension only, combine, can choose how deep to traverse - it provides a depth argument to specify the number of dimensions it iterates over. The elemental function of combine accesses the source array & the current index within it - element is computed by calling the get method of the source ParallelArray object with index i as argument. It requires more code but is more expressive. var source = new ParallelArray([1,2,3,4,5]); var plusOne = source.combine(function inc(i) { return this.get(i)+1; }); reduce reduces the elements from an array to a single scalar result – e.g. Sum. // Calculate the sum of the elements var source = new ParallelArray([1,2,3,4,5]); var sum = source.reduce(function plus(a,b) { return a+b; }); scan Like reduce, but stores the intermediate results – return a ParallelArray whose ith elements is the results of using the elemental function to reduce the elements between 0 and I in the original ParallelArray. // do a partial sum var source = new ParallelArray([1,2,3,4,5]); var psum = source.scan(function plus(a,b) { return a+b; }); //<1, 3, 6, 10, 15> scatter a reordering function - specify for a certain source index where it should be stored in the result array. An optional conflict function can prevent an exception if two source values are assigned the same position of the result: var source = new ParallelArray([1,2,3,4,5]); var reorder = source.scatter([4,0,3,1,2]); // <2, 4, 5, 3, 1> // if there is a conflict use the max. use 33 as a default value. var reorder = source.scatter([4,0,3,4,2], 33, function max(a, b) {return a>b?a:b; }); //<2, 33, 5, 3, 4> filter // filter out values that are not even var source = new ParallelArray([1,2,3,4,5]); var even = source.filter(function even(iv) { return (this.get(iv) % 2) == 0; }); // <2,4> Flatten used to collapse the outer dimensions of an array into a single dimension. pa = new ParallelArray([ [1,2], [3,4] ]); // <<1,2>,<3,4>> pa.flatten(); // <1,2,3,4> Partition used to restore the original shape of the array. var pa = new ParallelArray([1,2,3,4]); // <1,2,3,4> pa.partition(2); // <<1,2>,<3,4>> Get return value found at the indices or undefined if no such value exists. var pa = new ParallelArray([0,1,2,3,4], [10,11,12,13,14], [20,21,22,23,24]) pa.get([1,1]); // 11 pa.get([1]); // <10,11,12,13,14>

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  • Multi-level navigation controller on left-hand side of UISplitView with a small twist.

    - by user141146
    Hi. I'm trying make something similar to (but not exactly like) the email app found on the iPad. Specifically, I'd like to create a tab-based app, but each tab would present the user with a different UISplitView. Each UISplitView contains a Master and a Detail view (obviously). In each UISplitView I would like the Master to be a multi-level navigational controller where new UIViewControllers are pushed onto (or popped off of) the stack. This type of navigation within the UISplitView is where the application is similar to the native email app. To the best of my knowledge, the only place that has described a decent "splitviewcontroller inside of a uitabbarcontroller" is here: http://stackoverflow.com/questions/2475139/uisplitviewcontroller-in-a-tabbar-uitabbarcontroller and I've tried to follow the accepted answer. The accepted solution seems to work for me (i.e., I get a tab-bar controller that allows me to switch between different UISplitViews). The problem is that I don't know how to make the left-hand side of the UISplitView to be a multi-level navigation controller. Here is the code I used within my app delegate to create the initial "split view 'inside' of a tab bar controller" (it's pretty much as suggested in the aforementioned link). - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { NSMutableArray *tabArray = [NSMutableArray array]; NSMutableArray *array = [NSMutableArray array]; UISplitViewController *splitViewController = [[UISplitViewController alloc] init]; MainViewController *viewCont = [[MainViewController alloc] initWithNibName:@"MainViewController" bundle:nil]; [array addObject:viewCont]; [viewCont release]; viewCont = [[DetailViewController alloc] initWithNibName:@"DetailViewController" bundle:nil]; [array addObject:viewCont]; [viewCont release]; [splitViewController setViewControllers:array]; [tabArray addObject:splitViewController]; [splitViewController release]; array = [NSMutableArray array]; splitViewController = [[UISplitViewController alloc] init]; viewCont = [[Master2 alloc] initWithNibName:@"Master2" bundle:nil]; [array addObject:viewCont]; [viewCont release]; viewCont = [[Slave2 alloc] initWithNibName:@"Slave2" bundle:nil]; [array addObject:viewCont]; [viewCont release]; [splitViewController setViewControllers:array]; [tabArray addObject:splitViewController]; [splitViewController release]; // Add the tab bar controller's current view as a subview of the window [tabBarController setViewControllers:tabArray]; [window addSubview:tabBarController.view]; [window makeKeyAndVisible]; return YES; } the class MainViewController is a UIViewController that contains the following method: - (IBAction)push_me:(id)sender { M2 *m2 = [[[M2 alloc] initWithNibName:@"M2" bundle:nil] autorelease]; [self.navigationController pushViewController:m2 animated:YES]; } this method is attached (via interface builder) to a UIButton found within MainViewController.xib Obviously, the method above (push_me) is supposed to create a second UIViewController (called m2) and push m2 into view on the left-side of the split-view when the UIButton is pressed. And yet it does nothing when the button is pressed (even though I can tell that the method is called). Thoughts on where I'm going wrong? TIA!

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  • How does one track down an error using the YII Framework?

    - by ian
    I am learning the Yii Framework and I got this error wich does not really point to the specific pages I am working on or as far as i can tell show me where I should start looking for my problem. How do I make sense of this? As far as I can see all my 'type_id' references are typed in correctly. CException Description Property "Project.type_id" is not defined. Source File /Users/user/Dropbox/localhost/yii/framework/db/ar/CActiveRecord.php(107) 00095: */ 00096: public function __get($name) 00097: { 00098: if(isset($this->_attributes[$name])) 00099: return $this->_attributes[$name]; 00100: else if(isset($this->getMetaData()->columns[$name])) 00101: return null; 00102: else if(isset($this->_related[$name])) 00103: return $this->_related[$name]; 00104: else if(isset($this->getMetaData()->relations[$name])) 00105: return $this->getRelated($name); 00106: else 00107: return parent::__get($name); 00108: } 00109: 00110: /** 00111: * PHP setter magic method. 00112: * This method is overridden so that AR attributes can be accessed like properties. 00113: * @param string property name 00114: * @param mixed property value 00115: */ 00116: public function __set($name,$value) 00117: { 00118: if($this->setAttribute($name,$value)===false) 00119: { Stack Trace #0 /Users/user/Dropbox/localhost/yii/framework/db/ar/CActiveRecord.php(107): CComponent->__get('type_id') #1 /Users/user/Dropbox/localhost/trackstar/protected/views/project/_view.php(15): CActiveRecord->__get('type_id') #2 /Users/user/Dropbox/localhost/yii/framework/web/CBaseController.php(119): require('/Users/user/Dro...') #3 /Users/user/Dropbox/localhost/yii/framework/web/CBaseController.php(88): CBaseController->renderInternal('/Users/user/Dro...', Array, true) #4 /Users/user/Dropbox/localhost/yii/framework/web/CController.php(748): CBaseController->renderFile('/Users/user/Dro...', Array, true) #5 /Users/user/Dropbox/localhost/yii/framework/zii/widgets/CListView.php(215): CController->renderPartial('_view', Array) #6 /Users/user/Dropbox/localhost/yii/framework/zii/widgets/CBaseListView.php(152): CListView->renderItems() #7 [internal function]: CBaseListView->renderSection(Array) #8 /Users/user/Dropbox/localhost/yii/framework/zii/widgets/CBaseListView.php(135): preg_replace_callback('/{(\w+)}/', Array, '{summary}?{sort...') #9 /Users/user/Dropbox/localhost/yii/framework/zii/widgets/CBaseListView.php(121): CBaseListView->renderContent() #10 /Users/user/Dropbox/localhost/yii/framework/web/CBaseController.php(174): CBaseListView->run() #11 /Users/user/Dropbox/localhost/trackstar/protected/views/project/index.php(17): CBaseController->widget('zii.widgets.CLi...', Array) #12 /Users/user/Dropbox/localhost/yii/framework/web/CBaseController.php(119): require('/Users/user/Dro...') #13 /Users/user/Dropbox/localhost/yii/framework/web/CBaseController.php(88): CBaseController->renderInternal('/Users/user/Dro...', Array, true) #14 /Users/user/Dropbox/localhost/yii/framework/web/CController.php(748): CBaseController->renderFile('/Users/user/Dro...', Array, true) #15 /Users/user/Dropbox/localhost/yii/framework/web/CController.php(687): CController->renderPartial('index', Array, true) #16 /Users/user/Dropbox/localhost/trackstar/protected/controllers/ProjectController.php(148): CController->render('index', Array) #17 /Users/user/Dropbox/localhost/yii/framework/web/actions/CInlineAction.php(32): ProjectController->actionIndex() #18 /Users/user/Dropbox/localhost/yii/framework/web/CController.php(300): CInlineAction->run() #19 /Users/user/Dropbox/localhost/yii/framework/web/filters/CFilterChain.php(129): CController->runAction(Object(CInlineAction)) #20 /Users/user/Dropbox/localhost/yii/framework/web/filters/CFilter.php(41): CFilterChain->run() #21 /Users/user/Dropbox/localhost/yii/framework/web/CController.php(999): CFilter->filter(Object(CFilterChain)) #22 /Users/user/Dropbox/localhost/yii/framework/web/filters/CInlineFilter.php(59): CController->filterAccessControl(Object(CFilterChain)) #23 /Users/user/Dropbox/localhost/yii/framework/web/filters/CFilterChain.php(126): CInlineFilter->filter(Object(CFilterChain)) #24 /Users/user/Dropbox/localhost/yii/framework/web/CController.php(283): CFilterChain->run() #25 /Users/user/Dropbox/localhost/yii/framework/web/CController.php(257): CController->runActionWithFilters(Object(CInlineAction), Array) #26 /Users/user/Dropbox/localhost/yii/framework/web/CWebApplication.php(320): CController->run('') #27 /Users/user/Dropbox/localhost/yii/framework/web/CWebApplication.php(120): CWebApplication->runController('project') #28 /Users/user/Dropbox/localhost/yii/framework/base/CApplication.php(135): CWebApplication->processRequest() #29 /Users/user/Dropbox/localhost/trackstar/index.php(12): CApplication->run() #30 {main} 2011-10-17 18:17:18 Apache/2.2.17 (Unix) mod_ssl/2.2.17 OpenSSL/0.9.8r DAV/2 PHP/5.3.6 Yii Framework/1.1.2

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  • How do I sort an array of Person Objects by using compareto()?

    - by Adam
    Here is my code: > import java.util.Scanner; import java.util.Arrays; /** This class tests the Person class. */ public class PersonDemo { public static void main(String[] args) { int count = 0; Scanner in = new Scanner(System.in); boolean more = false; Person first = null; Person last = null; while (more) { System.out.println( "Please enter the person's name or a blank line to quit"); String name = in.nextLine(); if (name.equals("")) more = false; else { Person p = new Person(name); //new person object created with inputted name Person[] people = new Person[10]; //new array of 10 person objects people[count] = p; //declare person object with index of variable count as the new person object first = people[count]; // I have no idea what to do here. This is where I'm stuck. last = people[count]; // I can't figure out what to do with this either. first.compareTo(p); //call compareTo method on first and new person object last.compareTo(p); //call compareTo method on last and new person object count++; // increase count variable } } System.out.println("First: " + first.toString()); System.out.println("Last: " + last.toString()); } } And the Person class: /** A person with a name. */ public class Person implements Comparable { /** * Constructs a Person with a name. * @param aName the person's name */ public Person(String aName) { name = aName; } public String getName() { return name; } @Override public int compareTo(Object otherObject) { Person other = (Person)otherObject; if (name.compareTo(other.name) < 0) return -1; if (name.compareTo(other.name) > 0) return 1; return 0; } /** Returns a string representation of the object. @return name of Person */ public String toString() { return "[name=" + name + "]"; } private String name; }

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  • Why is my code returning a Null Object Refrence error when using WatIn?

    - by Fuzz Evans
    I keep getting a Null Object Refrence Error, but can't tell why. I have a CSV file that contains 100 urls. The file is read into an array called "lines". public partial class Form1 : System.Windows.Forms.Form { string[] lines; public Form1() ... private void ReadLinksIntoMemory() { //this reads the chosen csv file into our "lines" array //and splits on comma's and new lines to create new objects within the array using (StreamReader sr = new StreamReader(@"C:\temp.csv")) { //reads everything in our csv into 1 long line string fileContents = sr.ReadToEnd(); //splits the 1 long line read in into multiple objects of the lines array lines = fileContents.Split(new string[] { ",", Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries); sr.Dispose(); } } The next part is where I get the null object error. When I try to use WatIn to go to the first item in the lines array it says I'm referencing a null object. private void GoToEditLinks() { for (int i = 0; i < lines.Length; i++) { //go to each link sequentially myIE.GoTo(lines[i].ToString()); //sleep so we can make sure the page loads System.Threading.Thread.Sleep(5000); } } When I debug the code it says that the GoTo request calls lines which is null. It seems like I need to declare the array, but don't I need to tell it an exact size to do that? Example: lines = new string[10] I thought I could use the lines.Length to tell it how big to make the array but that didn't work. What is weird to me is I can use the following code without problem: //returns the accurate number of urls that were in the CSV we read in earlier txtbx1.text = lines.Length; //or //this returns the last entry in the csv, as well as the last entry in the array TextBox2.Text = lines[lines.Length - 1]; I am confused why the array clearly has items in it, they can be called to fill a text box, but when I try to call them in my for loop it says its a null reference? UPDATE: By placing my cursor on both calls to lines and pressing f12 I find they both go to the same instance. The thought next is that I am not calling ReadLinksIntoMemory in time, below is my code: private void button1_Click(object sender, EventArgs e) { button1.Enabled = false; ReadLinksIntoMemory(); GoToEditLinks(); button1.Enabled = true; } Unless I'm mistaken the code says that the ReadLinksIntoMemory method must complete before GoToEditLinks can be called? If ReadLinksIntoMemory didn't finish in time I shouldn't be able to fill my text boxes with the lines array length and/or last entry. UPDATE: Stepping into the method GoToEditLinks() I see that lines is null before it calls: myIE.GoTo(lines[i]); but when it hits the goto command the value changes from null to the url it is suppose to go to, but at that same time it gives me the null object error? UPDATE: I added a IsNullOrEmpty check method and lines array passes it without any issue. I'm beginning to think it is an issue with WatIn and the myIE.GoTo command. I think this is the stack trace/call stack? Program.exe!Program.Form1.GoToEditLinks() Line 284 C# Program.exe!Program.Form1.button1_Click(object sender, System.EventArgs e) Line 191 + 0x8 bytes C# [External Code] Program.exe!Program.Program.Main() Line 18 + 0x1d bytes C# [External Code]

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  • Ajax post request, an object that includes an array and other objects, can't be parsed correctly int

    - by Waheedi
    what i want is to get a proper parameter, if you see the parameter been logged you would tell there is something wrong my javasript: first run the runMe function Ajax: function() { var xmlhttp, bComplete = false; try { xmlhttp = new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) { try { xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); } catch (e) { try { xmlhttp = new XMLHttpRequest(); } catch (e) { xmlhttp = false; }}} if (!xmlhttp) return null; this.connect = function(sURL, sMethod, sVars, fnDone) { if (!xmlhttp) return false; bComplete = false; sMethod = sMethod.toUpperCase(); try { if (sMethod == "GET") { xmlhttp.open(sMethod, sURL+"?"+sVars, true); sVars = ""; } else { xmlhttp.open(sMethod, sURL); xmlhttp.setRequestHeader("Method", "POST "+sURL+" HTTP/1.1"); xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded"); xmlhttp.setRequestHeader("Content-length", sVars.length); } xmlhttp.onreadystatechange = function(){ if (xmlhttp.readyState == 4 && !bComplete) { bComplete = true; fnDone(xmlhttp); }}; xmlhttp.send(sVars); } catch(z) { return false; } return true; }; return this; }, tOrigin: function(origin){ this.origin = origin; }, tObject: function(origins,url,apik){ this.origins=origins; //this is an array this.url=url; this.apik=apik; this.host= "http://localhost:3000/";//window.location.hostname; } runMe: function(){ var t = new tObject(['this','word','word me please','and me please','word','word','okay','word','go','go'],window.location.href,"helloapik"); // console.log(t); ajax = new Ajax(); ajax.connect("http://localhost:3000/","POST",JSON.stringify(t), callBackFunc) } this is what I'm getting in my rails server log Parameters: {"{\"origins\":"={"{\"origin\":\"this\"},{\"origin\":\"word\"},{\"origin\":\"word me please\"},{\"origin\":\"and me please\"},{\"origin\":\"word\"},{\"origin\":\"word\"},{\"origin\":\"word\"},{\"origin\":\"okay\"},{\"origin\":\"word\"},{\"origin\":\"go\"},{\"origin\":\"go\"}"={",\"url\":\"file:///Users/waheed/Desktop/untitled.html\",\"apik\":\"helloapik\",\"host\":\"http://localhost:3000/\"}"=nil}}}

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  • Anyway that I can get the values of a PHP array through ajax?

    - by Jerry
    Hi All, I am trying to build a shopping cart site. When a user click add to cart image on the product page, The product title will show a "The product is in your cart" text without reloading the page. I am using session and ajax but no luck so far. I appreciate any helps. My html cold <table id="<?php echo $productId; ?>" width="594" border="0" cellpadding="5" cellspacing="0"> <tr> <td><img src="<?php echo "$brandImage"; ?></td> <td <?php echo $productName; ?> //The "The product is in your cart" will be showed here</td> </tr> <tr> <td><a class="addToCart" href="javascript:void(0);" onclick="addToCart(<?php echo $productId?>)"> </td> My Javascript file (addToCart.js) function addToCart(productId){ var url="addToCart.php"; url=url+"?productId="+productId; url=url+"&sid="+Math.random(); $.post( url, function(responseText){ alert(responseText); //I wish I can get productData value from addToCart.php }, "html" ) My php file (addToCart.php) <?php SESSION_START(); $productId=$_GET['productId']; $cart=$_SESSION['cart']; if(isset($cart)){ $cart.=",".$productId; $product=explode(',',$cart); $totalItem=count($product); }else{ $cart=$productId; $totalItem=1; }; $productData=array(); foreach($product as $id){ $productData[$id]=(isset($productData[$id])) ? $productData[$id]+1 :1; }; $_SESSION['cart']=$cart; //print_r($productData); echo $productData; //Not sure what to do to send $productData back to my addToCart.js variable ?> I tried to make the code look simple. Any suggestion will be a great help. Thanks

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  • Slicing a time range into parts

    - by beporter
    First question. Be gentle. I'm working on software that tracks technicians' time spent working on tasks. The software needs to be enhanced to recognize different billable rate multipliers based on the day of the week and the time of day. (For example, "Time and a half after 5 PM on weekdays.") The tech using the software is only required to log the date, his start time and his stop time (in hours and minutes). The software is expected to break the time entry into parts at the boundaries of when the rate multipliers change. A single time entry is not permitted to span multiple days. Here is a partial sample of the rate table. The first-level array keys are the days of the week, obviously. The second-level array keys represent the time of the day when the new multiplier kicks in, and runs until the next sequential entry in the array. The array values are the multiplier for that time range. [rateTable] => Array ( [Monday] => Array ( [00:00:00] => 1.5 [08:00:00] => 1 [17:00:00] => 1.5 [23:59:59] => 1 ) [Tuesday] => Array ( [00:00:00] => 1.5 [08:00:00] => 1 [17:00:00] => 1.5 [23:59:59] => 1 ) ... ) In plain English, this represents a time-and-a-half rate from midnight to 8 am, regular rate from 8 to 5 pm, and time-and-a-half again from 5 till 11:59 pm. The time that these breaks occur may be arbitrary to the second and there can be an arbitrary number of them for each day. (This format is entirely negotiable, but my goal is to make it as easily human-readable as possible.) As an example: a time entry logged on Monday from 15:00:00 (3 PM) to 21:00:00 (9 PM) would consist of 2 hours billed at 1x and 4 hours billed at 1.5x. It is also possible for a single time entry to span multiple breaks. Using the example rateTable above, a time entry from 6 AM to 9 PM would have 3 sub-ranges from 6-8 AM @ 1.5x, 8AM-5PM @ 1x, and 5-9 PM @ 1.5x. By contrast, it's also possible that a time entry may only be from 08:15:00 to 08:30:00 and be entirely encompassed in the range of a single multiplier. I could really use some help coding up some PHP (or at least devising an algorithm) that can take a day of the week, a start time and a stop time and parse into into the required subparts. It would be ideal to have the output be an array that consists of multiple entries for a (start,stop,multiplier) triplet. For the above example, the output would be: [output] => Array ( [0] => Array ( [start] => 15:00:00 [stop] => 17:00:00 [multiplier] => 1 ) [1] => Array ( [start] => 17:00:00 [stop] => 21:00:00 [multiplier] => 1.5 ) ) I just plain can't wrap my head around the logic of splitting a single (start,stop) into (potentially) multiple subparts.

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  • Help with C# program design implementation: multiple array of lists or a better way?

    - by Bob
    I'm creating a 2D tile-based RPG in XNA and am in the initial design phase. I was thinking of how I want my tile engine to work and came up with a rough sketch. Basically I want a grid of tiles, but at each tile location I want to be able to add more than one tile and have an offset. I'd like this so that I could do something like add individual trees on the world map to give more flair. Or set bottles on a bar in some town without having to draw a bunch of different bar tiles with varying bottles. But maybe my reach is greater than my grasp. I went to implement the idea and had something like this in my Map object: List<Tile>[,] Grid; But then I thought about it. Let's say I had a world map of 200x200, which would actually be pretty small as far as RPGs go. That would amount to 40,000 Lists. To my mind I think there has to be a better way. Now this IS pre-mature optimization. I don't know if the way I happen to design my maps and game will be able to handle this, but it seems needlessly inefficient and something that could creep up if my game gets more complex. One idea I have is to make the offset and the multiple tiles optional so that I'm only paying for them when needed. But I'm not sure how I'd do this. A multiple array of objects? object[,] Grid; So here's my criteria: A 2D grid of tile locations Each tile location has a minimum of 1 tile, but can optionally have more Each extra tile can optionally have an x and y offset for pinpoint placement Can anyone help with some ideas for implementing such a design (don't need it done for me, just ideas) while keeping memory usage to a minimum? If you need more background here's roughly what my Map and Tile objects amount to: public struct Map { public Texture2D Texture; public List<Rectangle> Sources; //Source Rectangles for where in Texture to get the sprite public List<Tile>[,] Grid; } public struct Tile { public int Index; //Where in Sources to find the source Rectangle public int X, Y; //Optional offsets }

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  • How to store array data in MySQL database using PHP & MySQL?

    - by Cyn
    I'm new to php and mysql and I'm trying to learn how to store the following array data from three different arrays friend[], hair_type[], hair_color[] using MySQL and PHP an example would be nice. Thanks Here is the HTML code. <input type="text" name="friend[]" id="friend[]" /> <select id="hair_type[]" name="hair_type[]"> <option value="Hair Type" selected="selected">Hair Type</option> <option value="Straight">Straight</option> <option value="Curly">Curly</option> <option value="Wavey">Wavey</option> <option value="Bald">Bald</option> </select> <select id="hair_color[]" name="hair_color[]"> <option value="Hair Color" selected="selected">Hair Color</option> <option value="Brown">Brown</option> <option value="Black">Black</option> <option value="Red">Red</option> <option value="Blonde">Blonde</option> </select> <input type="text" name="friend[]" id="friend[]" /> <select id="hair_type[]" name="hair_type[]"> <option value="Hair Type" selected="selected">Hair Type</option> <option value="Straight">Straight</option> <option value="Curly">Curly</option> <option value="Wavey">Wavey</option> <option value="Bald">Bald</option> </select> <select id="hair_color[]" name="hair_color[]"> <option value="Hair Color" selected="selected">Hair Color</option> <option value="Brown">Brown</option> <option value="Black">Black</option> <option value="Red">Red</option> <option value="Blonde">Blonde</option> </select> Here is the MySQL tables below. CREATE TABLE friends_hair ( id INT UNSIGNED NOT NULL AUTO_INCREMENT, hair_id INT UNSIGNED NOT NULL, user_id INT UNSIGNED NOT NULL, PRIMARY KEY (id) ); CREATE TABLE hair_types ( id INT UNSIGNED NOT NULL AUTO_INCREMENT, friend TEXT NOT NULL, hair_type TEXT NOT NULL, hair_color TEXT NOT NULL, PRIMARY KEY (id) );

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  • When I overload the assignment operator for my simple class array, I get the wrong answer I espect

    - by user299648
    //output is "01234 00000" but the output should be or what I want it to be is // "01234 01234" because of the assignment overloaded operator #include <iostream> using namespace std; class IntArray { public: IntArray() : size(10), used(0) { a= new int[10]; } IntArray(int s) : size(s), used(0) { a= new int[s]; } int& operator[]( int index ); IntArray& operator =( const IntArray& rightside ); ~IntArray() { delete [] a; } private: int *a; int size; int used;//for array position }; int main() { IntArray copy; if( 2>1) { IntArray arr(5); for( int k=0; k<5; k++) arr[k]=k; copy = arr; for( int j=0; j<5; j++) cout<<arr[j]; } cout<<" "; for( int j=0; j<5; j++) cout<<copy[j]; return 0; } int& IntArray::operator[]( int index ) { if( index >= size ) cout<<"ilegal index in IntArray"<<endl; return a[index]; } IntArray& IntArray::operator =( const IntArray& rightside ) { if( size != rightside.size )//also checks if on both side same object { delete [] a; a= new int[rightside.size]; } size=rightside.size; used=rightside.used; for( int i = 0; i < used; i++ ) a[i]=rightside.a[i]; return *this; }

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  • Return NSArray from NSDictionary

    - by Jon
    I have a fetch that returns an array with dictionary in it of an attribute of a core data object. Here is my previous question: Create Array From Attribute of NSObject From NSFetchResultsController This is the fetch: NSFetchRequest *request = [[NSFetchRequest alloc] init]; [request setEntity:entity]; [request setResultType:NSDictionaryResultType]; [request setReturnsDistinctResults:NO]; //set to YES if you only want unique values of the property [request setPropertiesToFetch :[NSArray arrayWithObject:@"timeStamp"]]; //name(s) of properties you want to fetch // Execute the fetch. NSError *error; NSArray *objects = [managedObjectContext executeFetchRequest:request error:&error]; When I log the NSArray data, I get this: The content of data is( { timeStamp = "2011-06-14 21:30:03 +0000"; }, { timeStamp = "2011-06-16 21:00:18 +0000"; }, { timeStamp = "2011-06-11 21:00:18 +0000"; }, { timeStamp = "2011-06-23 19:53:35 +0000"; }, { timeStamp = "2011-06-21 19:53:35 +0000"; } ) What I want is an array with this format: [NSArray arrayWithObjects: @"2011-11-01 00:00:00 +0000", @"2011-12-01 00:00:00 +0000", nil];' Edit: This is the method for which I want to replace the data array with my new data array: - (NSArray*)calendarMonthView:(TKCalendarMonthView *)monthView marksFromDate:(NSDate *)startDate toDate:(NSDate *)lastDate { NSLog(@"calendarMonthView marksFromDate toDate"); NSLog(@"Make sure to update 'data' variable to pull from CoreData, website, User Defaults, or some other source."); // When testing initially you will have to update the dates in this array so they are visible at the // time frame you are testing the code. NSArray *data = [NSArray arrayWithObjects: @"2011-01-01 00:00:00 +0000", @"2011-12-01 00:00:00 +0000", nil]; // Initialise empty marks array, this will be populated with TRUE/FALSE in order for each day a marker should be placed on. NSMutableArray *marks = [NSMutableArray array]; // Initialise calendar to current type and set the timezone to never have daylight saving NSCalendar *cal = [NSCalendar currentCalendar]; [cal setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]]; // Construct DateComponents based on startDate so the iterating date can be created. // Its massively important to do this assigning via the NSCalendar and NSDateComponents because of daylight saving has been removed // with the timezone that was set above. If you just used "startDate" directly (ie, NSDate *date = startDate;) as the first // iterating date then times would go up and down based on daylight savings. NSDateComponents *comp = [cal components:(NSMonthCalendarUnit | NSMinuteCalendarUnit | NSYearCalendarUnit | NSDayCalendarUnit | NSWeekdayCalendarUnit | NSHourCalendarUnit | NSSecondCalendarUnit) fromDate:startDate]; NSDate *d = [cal dateFromComponents:comp]; // Init offset components to increment days in the loop by one each time NSDateComponents *offsetComponents = [[NSDateComponents alloc] init]; [offsetComponents setDay:1]; // for each date between start date and end date check if they exist in the data array while (YES) { // Is the date beyond the last date? If so, exit the loop. // NSOrderedDescending = the left value is greater than the right if ([d compare:lastDate] == NSOrderedDescending) { break; } // If the date is in the data array, add it to the marks array, else don't if ([data containsObject:[d description]]) { [marks addObject:[NSNumber numberWithBool:YES]]; } else { [marks addObject:[NSNumber numberWithBool:NO]]; } // Increment day using offset components (ie, 1 day in this instance) d = [cal dateByAddingComponents:offsetComponents toDate:d options:0]; } [offsetComponents release]; return [NSArray arrayWithArray:marks]; }

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  • Sorting Algorithms

    - by MarkPearl
    General Every time I go back to university I find myself wading through sorting algorithms and their implementation in C++. Up to now I haven’t really appreciated their true value. However as I discovered this last week with Dictionaries in C# – having a knowledge of some basic programming principles can greatly improve the performance of a system and make one think twice about how to tackle a problem. I’m going to cover briefly in this post the following: Selection Sort Insertion Sort Shellsort Quicksort Mergesort Heapsort (not complete) Selection Sort Array based selection sort is a simple approach to sorting an unsorted array. Simply put, it repeats two basic steps to achieve a sorted collection. It starts with a collection of data and repeatedly parses it, each time sorting out one element and reducing the size of the next iteration of parsed data by one. So the first iteration would go something like this… Go through the entire array of data and find the lowest value Place the value at the front of the array The second iteration would go something like this… Go through the array from position two (position one has already been sorted with the smallest value) and find the next lowest value in the array. Place the value at the second position in the array This process would be completed until the entire array had been sorted. A positive about selection sort is that it does not make many item movements. In fact, in a worst case scenario every items is only moved once. Selection sort is however a comparison intensive sort. If you had 10 items in a collection, just to parse the collection you would have 10+9+8+7+6+5+4+3+2=54 comparisons to sort regardless of how sorted the collection was to start with. If you think about it, if you applied selection sort to a collection already sorted, you would still perform relatively the same number of iterations as if it was not sorted at all. Many of the following algorithms try and reduce the number of comparisons if the list is already sorted – leaving one with a best case and worst case scenario for comparisons. Likewise different approaches have different levels of item movement. Depending on what is more expensive, one may give priority to one approach compared to another based on what is more expensive, a comparison or a item move. Insertion Sort Insertion sort tries to reduce the number of key comparisons it performs compared to selection sort by not “doing anything” if things are sorted. Assume you had an collection of numbers in the following order… 10 18 25 30 23 17 45 35 There are 8 elements in the list. If we were to start at the front of the list – 10 18 25 & 30 are already sorted. Element 5 (23) however is smaller than element 4 (30) and so needs to be repositioned. We do this by copying the value at element 5 to a temporary holder, and then begin shifting the elements before it up one. So… Element 5 would be copied to a temporary holder 10 18 25 30 23 17 45 35 – T 23 Element 4 would shift to Element 5 10 18 25 30 30 17 45 35 – T 23 Element 3 would shift to Element 4 10 18 25 25 30 17 45 35 – T 23 Element 2 (18) is smaller than the temporary holder so we put the temporary holder value into Element 3. 10 18 23 25 30 17 45 35 – T 23   We now have a sorted list up to element 6. And so we would repeat the same process by moving element 6 to a temporary value and then shifting everything up by one from element 2 to element 5. As you can see, one major setback for this technique is the shifting values up one – this is because up to now we have been considering the collection to be an array. If however the collection was a linked list, we would not need to shift values up, but merely remove the link from the unsorted value and “reinsert” it in a sorted position. Which would reduce the number of transactions performed on the collection. So.. Insertion sort seems to perform better than selection sort – however an implementation is slightly more complicated. This is typical with most sorting algorithms – generally, greater performance leads to greater complexity. Also, insertion sort performs better if a collection of data is already sorted. If for instance you were handed a sorted collection of size n, then only n number of comparisons would need to be performed to verify that it is sorted. It’s important to note that insertion sort (array based) performs a number item moves – every time an item is “out of place” several items before it get shifted up. Shellsort – Diminishing Increment Sort So up to now we have covered Selection Sort & Insertion Sort. Selection Sort makes many comparisons and insertion sort (with an array) has the potential of making many item movements. Shellsort is an approach that takes the normal insertion sort and tries to reduce the number of item movements. In Shellsort, elements in a collection are viewed as sub-collections of a particular size. Each sub-collection is sorted so that the elements that are far apart move closer to their final position. Suppose we had a collection of 15 elements… 10 20 15 45 36 48 7 60 18 50 2 19 43 30 55 First we may view the collection as 7 sub-collections and sort each sublist, lets say at intervals of 7 10 60 55 – 20 18 – 15 50 – 45 2 – 36 19 – 48 43 – 7 30 10 55 60 – 18 20 – 15 50 – 2 45 – 19 36 – 43 48 – 7 30 (Sorted) We then sort each sublist at a smaller inter – lets say 4 10 55 60 18 – 20 15 50 2 – 45 19 36 43 – 48 7 30 10 18 55 60 – 2 15 20 50 – 19 36 43 45 – 7 30 48 (Sorted) We then sort elements at a distance of 1 (i.e. we apply a normal insertion sort) 10 18 55 60 2 15 20 50 19 36 43 45 7 30 48 2 7 10 15 18 19 20 30 36 43 45 48 50 55 (Sorted) The important thing with shellsort is deciding on the increment sequence of each sub-collection. From what I can tell, there isn’t any definitive method and depending on the order of your elements, different increment sequences may perform better than others. There are however certain increment sequences that you may want to avoid. An even based increment sequence (e.g. 2 4 8 16 32 …) should typically be avoided because it does not allow for even elements to be compared with odd elements until the final sort phase – which in a way would negate many of the benefits of using sub-collections. The performance on the number of comparisons and item movements of Shellsort is hard to determine, however it is considered to be considerably better than the normal insertion sort. Quicksort Quicksort uses a divide and conquer approach to sort a collection of items. The collection is divided into two sub-collections – and the two sub-collections are sorted and combined into one list in such a way that the combined list is sorted. The algorithm is in general pseudo code below… Divide the collection into two sub-collections Quicksort the lower sub-collection Quicksort the upper sub-collection Combine the lower & upper sub-collection together As hinted at above, quicksort uses recursion in its implementation. The real trick with quicksort is to get the lower and upper sub-collections to be of equal size. The size of a sub-collection is determined by what value the pivot is. Once a pivot is determined, one would partition to sub-collections and then repeat the process on each sub collection until you reach the base case. With quicksort, the work is done when dividing the sub-collections into lower & upper collections. The actual combining of the lower & upper sub-collections at the end is relatively simple since every element in the lower sub-collection is smaller than the smallest element in the upper sub-collection. Mergesort With quicksort, the average-case complexity was O(nlog2n) however the worst case complexity was still O(N*N). Mergesort improves on quicksort by always having a complexity of O(nlog2n) regardless of the best or worst case. So how does it do this? Mergesort makes use of the divide and conquer approach to partition a collection into two sub-collections. It then sorts each sub-collection and combines the sorted sub-collections into one sorted collection. The general algorithm for mergesort is as follows… Divide the collection into two sub-collections Mergesort the first sub-collection Mergesort the second sub-collection Merge the first sub-collection and the second sub-collection As you can see.. it still pretty much looks like quicksort – so lets see where it differs… Firstly, mergesort differs from quicksort in how it partitions the sub-collections. Instead of having a pivot – merge sort partitions each sub-collection based on size so that the first and second sub-collection of relatively the same size. This dividing keeps getting repeated until the sub-collections are the size of a single element. If a sub-collection is one element in size – it is now sorted! So the trick is how do we put all these sub-collections together so that they maintain their sorted order. Sorted sub-collections are merged into a sorted collection by comparing the elements of the sub-collection and then adjusting the sorted collection. Lets have a look at a few examples… Assume 2 sub-collections with 1 element each 10 & 20 Compare the first element of the first sub-collection with the first element of the second sub-collection. Take the smallest of the two and place it as the first element in the sorted collection. In this scenario 10 is smaller than 20 so 10 is taken from sub-collection 1 leaving that sub-collection empty, which means by default the next smallest element is in sub-collection 2 (20). So the sorted collection would be 10 20 Lets assume 2 sub-collections with 2 elements each 10 20 & 15 19 So… again we would Compare 10 with 15 – 10 is the winner so we add it to our sorted collection (10) leaving us with 20 & 15 19 Compare 20 with 15 – 15 is the winner so we add it to our sorted collection (10 15) leaving us with 20 & 19 Compare 20 with 19 – 19 is the winner so we add it to our sorted collection (10 15 19) leaving us with 20 & _ 20 is by default the winner so our sorted collection is 10 15 19 20. Make sense? Heapsort (still needs to be completed) So by now I am tired of sorting algorithms and trying to remember why they were so important. I think every year I go through this stuff I wonder to myself why are we made to learn about selection sort and insertion sort if they are so bad – why didn’t we just skip to Mergesort & Quicksort. I guess the only explanation I have for this is that sometimes you learn things so that you can implement them in future – and other times you learn things so that you know it isn’t the best way of implementing things and that you don’t need to implement it in future. Anyhow… luckily this is going to be the last one of my sorts for today. The first step in heapsort is to convert a collection of data into a heap. After the data is converted into a heap, sorting begins… So what is the definition of a heap? If we have to convert a collection of data into a heap, how do we know when it is a heap and when it is not? The definition of a heap is as follows: A heap is a list in which each element contains a key, such that the key in the element at position k in the list is at least as large as the key in the element at position 2k +1 (if it exists) and 2k + 2 (if it exists). Does that make sense? At first glance I’m thinking what the heck??? But then after re-reading my notes I see that we are doing something different – up to now we have really looked at data as an array or sequential collection of data that we need to sort – a heap represents data in a slightly different way – although the data is stored in a sequential collection, for a sequential collection of data to be in a valid heap – it is “semi sorted”. Let me try and explain a bit further with an example… Example 1 of Potential Heap Data Assume we had a collection of numbers as follows 1[1] 2[2] 3[3] 4[4] 5[5] 6[6] For this to be a valid heap element with value of 1 at position [1] needs to be greater or equal to the element at position [3] (2k +1) and position [4] (2k +2). So in the above example, the collection of numbers is not in a valid heap. Example 2 of Potential Heap Data Lets look at another collection of numbers as follows 6[1] 5[2] 4[3] 3[4] 2[5] 1[6] Is this a valid heap? Well… element with the value 6 at position 1 must be greater or equal to the element at position [3] and position [4]. Is 6 > 4 and 6 > 3? Yes it is. Lets look at element 5 as position 2. It must be greater than the values at [4] & [5]. Is 5 > 3 and 5 > 2? Yes it is. If you continued to examine this second collection of data you would find that it is in a valid heap based on the definition of a heap.

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  • Java: Cannot find a method's symbol even though that method is declared later in the class. The remaining code is looking for a class.

    - by Midimistro
    This is an assignment that we use strings in Java to analyze a phone number. The error I am having is anything below tester=invalidCharacters(c); does not compile because every line past tester=invalidCharacters(c); is looking for a symbol or the class. In get invalidResults, all I am trying to do is evaluate a given string for non-alphabetical characters such as *,(,^,&,%,@,#,), and so on. What to answer: Why is it producing an error, what will work, and is there an easier method WITHOUT using regex. Here is the link to the assignment: http://cis.csuohio.edu/~hwang/teaching/cis260/assignments/assignment9.html public class PhoneNumber { private int areacode; private int number; private int ext; /////Constructors///// //Third Constructor (given one string arg) "xxx-xxxxxxx" where first three are numbers and the remaining (7) are numbers or letters public PhoneNumber(String newNumber){ //Note: Set default ext to 0 ext=0; ////Declare Temporary Storage and other variables//// //for the first three numbers String areaCodeString; //for the remaining seven characters String newNumberString; //For use in testing the second half of the string boolean containsLetters; boolean containsInvalid; /////Separate the two parts of string///// //Get the area code part of the string areaCodeString=newNumber.substring(0,2); //Convert the string and set it to the area code areacode=Integer.parseInt(areaCodeString); //Skip the "-" and Get the remaining part of the string newNumberString=newNumber.substring(4); //Create an array of characters from newNumberString to reuse in later methods for int length=newNumberString.length(); char [] myCharacters= new char [length]; int i; for (i=0;i<length;i++){ myCharacters [i]=newNumberString.charAt(i); } //Test if newNumberString contains letters & converting them into numbers String reNewNumber=""; //Test for invalid characters containsInvalid=getInvalidResults(newNumberString,length); if (containsInvalid==false){ containsLetters=getCharResults(newNumberString,length); if (containsLetters==true){ for (i=0;i<length;i++){ myCharacters [i]=(char)convertLetNum((myCharacters [i])); reNewNumber=reNewNumber+myCharacters[i]; } } } if (containsInvalid==false){ number=Integer.parseInt(reNewNumber); } else{ System.out.println("Error!"+"\t"+newNumber+" contains illegal characters. This number will be ignored and skipped."); } } //////Primary Methods/Behaviors/////// //Compare this phone number with the one passed by the caller public boolean equals(PhoneNumber pn){ boolean equal; String concat=(areacode+"-"+number); String pN=pn.toString(); if (concat==pN){ equal=true; } else{ equal=false; } return equal; } //Convert the stored number to a certain string depending on extension public String toString(){ String returned; if(ext==0){ returned=(areacode+"-"+number); } else{ returned=(areacode+"-"+number+" ext "+ext); } return returned; } //////Secondary Methods/////// //Method for testing if the second part of the string contains any letters public static boolean getCharResults(String newNumString,int getLength){ //Recreate a character array int i; char [] myCharacters= new char [getLength]; for (i=0;i<getLength;i++){ myCharacters [i]=newNumString.charAt(i); } boolean doesContainLetter=false; int j; for (j=0;j<getLength;j++){ if ((Character.isDigit(myCharacters[j])==true)){ doesContainLetter=false; } else{ doesContainLetter=true; return doesContainLetter; } } return doesContainLetter; } //Method for testing if the second part of the string contains any letters public static boolean getInvalidResults(String newNumString,int getLength){ boolean doesContainInvalid=false; int i; char c; boolean tester; char [] invalidCharacters= new char [getLength]; for (i=0;i<getLength;i++){ invalidCharacters [i]=newNumString.charAt(i); c=invalidCharacters [i]; tester=invalidCharacters(c); if(tester==true)){ doesContainInvalid=false; } else{ doesContainInvalid=true; return doesContainInvalid; } } return doesContainInvalid; } //Method for evaluating string for invalid characters public boolean invalidCharacters(char letter){ boolean returnNum=false; switch (letter){ case 'A': return returnNum; case 'B': return returnNum; case 'C': return returnNum; case 'D': return returnNum; case 'E': return returnNum; case 'F': return returnNum; case 'G': return returnNum; case 'H': return returnNum; case 'I': return returnNum; case 'J': return returnNum; case 'K': return returnNum; case 'L': return returnNum; case 'M': return returnNum; case 'N': return returnNum; case 'O': return returnNum; case 'P': return returnNum; case 'Q': return returnNum; case 'R': return returnNum; case 'S': return returnNum; case 'T': return returnNum; case 'U': return returnNum; case 'V': return returnNum; case 'W': return returnNum; case 'X': return returnNum; case 'Y': return returnNum; case 'Z': return returnNum; default: return true; } } //Method for converting letters to numbers public int convertLetNum(char letter){ int returnNum; switch (letter){ case 'A': returnNum=2;return returnNum; case 'B': returnNum=2;return returnNum; case 'C': returnNum=2;return returnNum; case 'D': returnNum=3;return returnNum; case 'E': returnNum=3;return returnNum; case 'F': returnNum=3;return returnNum; case 'G': returnNum=4;return returnNum; case 'H': returnNum=4;return returnNum; case 'I': returnNum=4;return returnNum; case 'J': returnNum=5;return returnNum; case 'K': returnNum=5;return returnNum; case 'L': returnNum=5;return returnNum; case 'M': returnNum=6;return returnNum; case 'N': returnNum=6;return returnNum; case 'O': returnNum=6;return returnNum; case 'P': returnNum=7;return returnNum; case 'Q': returnNum=7;return returnNum; case 'R': returnNum=7;return returnNum; case 'S': returnNum=7;return returnNum; case 'T': returnNum=8;return returnNum; case 'U': returnNum=8;return returnNum; case 'V': returnNum=8;return returnNum; case 'W': returnNum=9;return returnNum; case 'X': returnNum=9;return returnNum; case 'Y': returnNum=9;return returnNum; case 'Z': returnNum=9;return returnNum; default: return 0; } } } Note: Please Do not use this program to cheat in your own class. To ensure of this, I will take this question down if it has not been answered by the end of 2013, if I no longer need an explanation for it, or if the term for the class has ended.

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  • java inserting special characters with preparedstatement fails

    - by phill
    I am using an HTML form which sends <input type=hidden name=longdesc value='SMARTNET%^" 8X5XNBD'> this is done by the following javascript code: function masinsert(id) { var currentTime=new Date(); var button = document.getElementById("m"+id); button.onclick=""; button.value="Inserting"; var itemdescription = document.getElementById("itemdescription"+id).value; function handleHttpResponse() { if (http.readyState == 4) { button.value="Item Added"; } } var http = getHTTPObject(); // We create the HTTP Object var tempUrl = "\AInsert"; tempUrl += "itemdescription="+itemdescription+"&"+"itemshortdescription="+itemdescription.substring(0,37)+; alert(tempUrl); http.open("GET", tempUrl, true); http.onreadystatechange = handleHttpResponse; http.send(null); } to a java servlet. AInsert.java in the AInsert.java file, I do a String itemdescription = request.getParameter("longdesc"); which then sends the value to a preparedstatement to run an insert query. In the query, there are sometimes special characters which throw it off. For example, when I run the following insert into itemdescription (longdesc) values ('SMARTNET%^" 8X5XNBD') here is the actual snippet: PreparedStatement ps = conn.prepareStatement("INSERT INTO itemdescription (longdesc) values(?)"); ps.setString(1, itemdescription); ps.executeUpdate(); It will produce an error saying : Cannot insert the value NULL into column 'LongDesc', table 'App.dbo.itemdescription'; column does not allow nulls. Insert fails I have tried urlencode/urldecode String encodedString = URLEncoder.encode(longdesc, "UTF-8"); String decitemdescription = URLDecoder.decode(itemdescription, "UTF-8"); and i've also tried these functions //BEGIN URL Encoder final static String[] hex = { "%00", "%01", "%02", "%03", "%04", "%05", "%06", "%07", "%08", "%09", "%0a", "%0b", "%0c", "%0d", "%0e", "%0f", "%10", "%11", "%12", "%13", "%14", "%15", "%16", "%17", "%18", "%19", "%1a", "%1b", "%1c", "%1d", "%1e", "%1f", "%20", "%21", "%22", "%23", "%24", "%25", "%26", "%27", "%28", "%29", "%2a", "%2b", "%2c", "%2d", "%2e", "%2f", "%30", "%31", "%32", "%33", "%34", "%35", "%36", "%37", "%38", "%39", "%3a", "%3b", "%3c", "%3d", "%3e", "%3f", "%40", "%41", "%42", "%43", "%44", "%45", "%46", "%47", "%48", "%49", "%4a", "%4b", "%4c", "%4d", "%4e", "%4f", "%50", "%51", "%52", "%53", "%54", "%55", "%56", "%57", "%58", "%59", "%5a", "%5b", "%5c", "%5d", "%5e", "%5f", "%60", "%61", "%62", "%63", "%64", "%65", "%66", "%67", "%68", "%69", "%6a", "%6b", "%6c", "%6d", "%6e", "%6f", "%70", "%71", "%72", "%73", "%74", "%75", "%76", "%77", "%78", "%79", "%7a", "%7b", "%7c", "%7d", "%7e", "%7f", "%80", "%81", "%82", "%83", "%84", "%85", "%86", "%87", "%88", "%89", "%8a", "%8b", "%8c", "%8d", "%8e", "%8f", "%90", "%91", "%92", "%93", "%94", "%95", "%96", "%97", "%98", "%99", "%9a", "%9b", "%9c", "%9d", "%9e", "%9f", "%a0", "%a1", "%a2", "%a3", "%a4", "%a5", "%a6", "%a7", "%a8", "%a9", "%aa", "%ab", "%ac", "%ad", "%ae", "%af", "%b0", "%b1", "%b2", "%b3", "%b4", "%b5", "%b6", "%b7", "%b8", "%b9", "%ba", "%bb", "%bc", "%bd", "%be", "%bf", "%c0", "%c1", "%c2", "%c3", "%c4", "%c5", "%c6", "%c7", "%c8", "%c9", "%ca", "%cb", "%cc", "%cd", "%ce", "%cf", "%d0", "%d1", "%d2", "%d3", "%d4", "%d5", "%d6", "%d7", "%d8", "%d9", "%da", "%db", "%dc", "%dd", "%de", "%df", "%e0", "%e1", "%e2", "%e3", "%e4", "%e5", "%e6", "%e7", "%e8", "%e9", "%ea", "%eb", "%ec", "%ed", "%ee", "%ef", "%f0", "%f1", "%f2", "%f3", "%f4", "%f5", "%f6", "%f7", "%f8", "%f9", "%fa", "%fb", "%fc", "%fd", "%fe", "%ff" }; /** * Encode a string to the "x-www-form-urlencoded" form, enhanced * with the UTF-8-in-URL proposal. This is what happens: * * <ul> * <li><p>The ASCII characters 'a' through 'z', 'A' through 'Z', * and '0' through '9' remain the same. * * <li><p>The unreserved characters - _ . ! ~ * ' ( ) remain the same. * * <li><p>The space character ' ' is converted into a plus sign '+'. * * <li><p>All other ASCII characters are converted into the * 3-character string "%xy", where xy is * the two-digit hexadecimal representation of the character * code * * <li><p>All non-ASCII characters are encoded in two steps: first * to a sequence of 2 or 3 bytes, using the UTF-8 algorithm; * secondly each of these bytes is encoded as "%xx". * </ul> * * @param s The string to be encoded * @return The encoded string */ public static String encode(String s) { StringBuffer sbuf = new StringBuffer(); int len = s.length(); for (int i = 0; i < len; i++) { int ch = s.charAt(i); if ('A' <= ch && ch <= 'Z') { // 'A'..'Z' sbuf.append((char)ch); } else if ('a' <= ch && ch <= 'z') { // 'a'..'z' sbuf.append((char)ch); } else if ('0' <= ch && ch <= '9') { // '0'..'9' sbuf.append((char)ch); } else if (ch == ' ') { // space sbuf.append('+'); } else if (ch == '-' || ch == '_' // unreserved || ch == '.' || ch == '!' || ch == '~' || ch == '*' || ch == '\'' || ch == '(' || ch == ')') { sbuf.append((char)ch); } else if (ch <= 0x007f) { // other ASCII sbuf.append(hex[ch]); } else if (ch <= 0x07FF) { // non-ASCII <= 0x7FF sbuf.append(hex[0xc0 | (ch >> 6)]); sbuf.append(hex[0x80 | (ch & 0x3F)]); } else { // 0x7FF < ch <= 0xFFFF sbuf.append(hex[0xe0 | (ch >> 12)]); sbuf.append(hex[0x80 | ((ch >> 6) & 0x3F)]); sbuf.append(hex[0x80 | (ch & 0x3F)]); } } return sbuf.toString(); } //end encode and //decode url private static String unescape(String s) { StringBuffer sbuf = new StringBuffer () ; int l = s.length() ; int ch = -1 ; int b, sumb = 0; for (int i = 0, more = -1 ; i < l ; i++) { /* Get next byte b from URL segment s */ switch (ch = s.charAt(i)) { case '%': ch = s.charAt (++i) ; int hb = (Character.isDigit ((char) ch) ? ch - '0' : 10+Character.toLowerCase((char) ch) - 'a') & 0xF ; ch = s.charAt (++i) ; int lb = (Character.isDigit ((char) ch) ? ch - '0' : 10+Character.toLowerCase ((char) ch)-'a') & 0xF ; b = (hb << 4) | lb ; break ; case '+': b = ' ' ; break ; default: b = ch ; } /* Decode byte b as UTF-8, sumb collects incomplete chars */ if ((b & 0xc0) == 0x80) { // 10xxxxxx (continuation byte) sumb = (sumb << 6) | (b & 0x3f) ; // Add 6 bits to sumb if (--more == 0) sbuf.append((char) sumb) ; // Add char to sbuf } else if ((b & 0x80) == 0x00) { // 0xxxxxxx (yields 7 bits) sbuf.append((char) b) ; // Store in sbuf } else if ((b & 0xe0) == 0xc0) { // 110xxxxx (yields 5 bits) sumb = b & 0x1f; more = 1; // Expect 1 more byte } else if ((b & 0xf0) == 0xe0) { // 1110xxxx (yields 4 bits) sumb = b & 0x0f; more = 2; // Expect 2 more bytes } else if ((b & 0xf8) == 0xf0) { // 11110xxx (yields 3 bits) sumb = b & 0x07; more = 3; // Expect 3 more bytes } else if ((b & 0xfc) == 0xf8) { // 111110xx (yields 2 bits) sumb = b & 0x03; more = 4; // Expect 4 more bytes } else /*if ((b & 0xfe) == 0xfc)*/ { // 1111110x (yields 1 bit) sumb = b & 0x01; more = 5; // Expect 5 more bytes } /* We don't test if the UTF-8 encoding is well-formed */ } return sbuf.toString() ; } but the decoding doesn't change it back to the original special characters. Any ideas? thanks in advance UPDATE: I tried adding these two statements to grab the request String itemdescription = URLDecoder.decode(request.getParameter("itemdescription"), "UTF-8"); String itemshortdescription = URLDecoder.decode(request.getParameter("itemshortdescription"), "UTF-8"); System.out.println("processRequest | short descrip "); and this is failing as well if that helps. UPDATE2: I created an html form and did a direct insert with the encoded itemdescription such as and the insertion works correctly with the special charaters and everything. I guess there is something going on with my javascript submit. Any ideas on this?

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  • To copy data from a webpage into an array of structs and sorted by“name” before producing the data.

    - by Taylor
    include include include include using namespace std; struct productJewelry { string name; double amount; int itemCode; double size; string group; }; int main() { // declare variables ifstream inFile; int count=0; int x=0; productJewelry product[50]; inFile.open("jewelry.txt"); // file must be in same folder if (inFile.fail()) cout << "failed"; cout << fixed << showpoint; // fixed format, two decimal places cout << setprecision(2); while (inFile.peek() != EOF) { // cout << count << " : "; count++; inFile product[x].itemCode; inFile product[x].name; inFile product[x].size; inFile product[x].amount; inFile product[x].group; // cout << product[x].itemCode << ", " << product[x].name << ", "<< product[x].size << ", " << product[x].amount << endl; x++; if (inFile.peek() == '\n') inFile.ignore(1, '\n'); } inFile.close(); string temp; bool swap; do { swap = false; for (int x=0; xproduct[x+1].name) { //these 3 lines are to swap elements in array temp=product[x].name; product[x].name=product[x+1].name; product[x+1].name=temp; swap=true; } } } while (swap); for (x=0; x< count; x++) { //cout<< product[x].itemCode<<" "; //cout<< product[x].name <<" "; //cout<< product[x].size <<" "; //cout<< product[x].amount<<" "; //cout<< product[x].group<<" "<<endl; } system("pause"); // to freeze Dev-c++ output screen return 0; } // end main THE FILE THAT NEEDS TO PRINT AND BE SORTED IN ALPHABETICAL ORDER 0011 Money_Clip 2.000 50.00 Other 0035 Paperweight 1.625 175.00 Other 0457 Cuff_Bracelet 2.375 150.00 Bracelet 0465 Links_Bracelet 7.125 425.00 Bracelet 0585 Key_Chain 1.325 50.00 Other 0595 Cuff_Links 0.625 525.00 Other 0935 Royale_Pendant 0.625 975.00 Pendant 1092 Bordeaux_Cross 1.625 425.00 Cross 1105 Victory_Medallion 0.875 30.00 Pendant 1111 Marquis_Cross 1.375 70.00 Cross 1160 Christina_Ring 0.500 175.00 Ring 1511 French_Clips 0.687 375.00 Other 1717 Pebble_Pendant 1.250 45.00 Pendant 1725 Folded_Pendant 1.250 45.00 Pendant 1730 Curio_Pendant 1.063 275.00 Pendant

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  • To copy data from a webpage into an array of structs and sorted by"name" before producing the data.

    - by Taylor
    include include include include using namespace std; struct productJewelry { string name; double amount; int itemCode; double size; string group; }; int main() { // declare variables ifstream inFile; int count=0; int x=0; productJewelry product[50]; inFile.open("jewelry.txt"); // file must be in same folder if (inFile.fail()) cout << "failed"; cout << fixed << showpoint; // fixed format, two decimal places cout << setprecision(2); while (inFile.peek() != EOF) { // cout << count << " : "; count++; inFile product[x].itemCode; inFile product[x].name; inFile product[x].size; inFile product[x].amount; inFile product[x].group; // cout << product[x].itemCode << ", " << product[x].name << ", "<< product[x].size << ", " << product[x].amount << endl; x++; if (inFile.peek() == '\n') inFile.ignore(1, '\n'); } inFile.close(); string temp; bool swap; do { swap = false; for (int x=0; xproduct[x+1].name) { //these 3 lines are to swap elements in array temp=product[x].name; product[x].name=product[x+1].name; product[x+1].name=temp; swap=true; } } } while (swap); for (x=0; x< count; x++) { //cout<< product[x].itemCode<<" "; //cout<< product[x].name <<" "; //cout<< product[x].size <<" "; //cout<< product[x].amount<<" "; //cout<< product[x].group<<" "<<endl; } system("pause"); // to freeze Dev-c++ output screen return 0; } // end main

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  • How to get data from dynamically created EditText views and insert it into an array?

    - by Snwspeckle
    So basically what I need my program to do at this point is that when I click the submit button, I need to loop through each dynamic row of the ListView and grab the value in the EditText view and then insert that into an array which I will do further calculations after. Here is my code right now. package com.hello_world; import java.util.ArrayList; import com.hello_world.ByteInputActivity.MyAdapter.ViewHolder; import android.app.Activity; import android.content.Context; import android.os.Bundle; import android.util.Log; import android.view.KeyEvent; import android.view.LayoutInflater; import android.view.View; import android.view.View.OnFocusChangeListener; import android.view.View.OnKeyListener; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.Button; import android.widget.EditText; import android.widget.ListView; import android.widget.TextView; public class ByteInputActivity extends Activity { private ListView myList; private MyAdapter myAdapter; private Integer resQuestions; private Integer indexVal = 0; private View caption; ViewHolder holder; ArrayList<Integer> intArrayList = new ArrayList<Integer>(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.fieldlist); //Gets number of questions from MainActivity Bundle extras = getIntent().getExtras(); if(extras !=null) { resQuestions = extras.getInt("index"); } myList = (ListView) findViewById(R.id.FieldList); myList.setItemsCanFocus(true); myAdapter = new MyAdapter(); myList.setAdapter(myAdapter); Button submit = (Button) findViewById(R.id.btn_New); submit.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { for (int i = 0; i < myList.getCount() ; i++) { View vListSortOrder; vListSortOrder = myList.getChildAt(i); String temp = holder.caption.getText().toString(); Log.e("VALUES", "" +temp); } } }); } public class MyAdapter extends BaseAdapter { private LayoutInflater mInflater; public ArrayList myItems = new ArrayList(); public MyAdapter() { mInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); for (int i = 0; i < resQuestions; i++) { ListItem listItem = new ListItem(); listItem.caption = "Index " + i; listItem.indexText = "Index " + i; myItems.add(listItem); indexVal += 1; } notifyDataSetChanged(); } public int getCount() { return myItems.size(); } public Object getItem(int position) { return position; } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent) { if (convertView == null) { holder = new ViewHolder(); convertView = mInflater.inflate(R.layout.item, null); holder.indexText = (TextView) convertView .findViewById(R.id.textView1); holder.caption = (EditText) convertView .findViewById(R.id.ItemCaption); convertView.setTag(holder); } else { holder = (ViewHolder) convertView.getTag(); } //Fill EditText with the value you have in data source holder.caption.setText(""); holder.caption.setId(position); holder.indexText.setText("Index " + position); holder.indexText.setId(position); //we need to update adapter once we finish with editing holder.caption.setOnFocusChangeListener(new OnFocusChangeListener() { public void onFocusChange(View v, boolean hasFocus) { if (!hasFocus){ final int position = v.getId(); final EditText Caption = (EditText) v; myItems.set(position, Caption.getText().toString()); } } }); return convertView; } class ViewHolder { EditText caption; TextView indexText; } class ListItem { String caption; String indexText; } } }

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  • RAID 5 configuration and future expansion

    - by Alexis Hirst
    hi, I am building a PC to act as a file server among other things, and I was wondering whether it is a good idea to create 2 partitions on the RAID 5 array, one for OS one for data, or to have a separate disk for OS and use array for data. Also, one day i may want to add another disk to the array, so would there be any issues if I had the OS partition on the RAID5 array when it came to resizing the data partition?

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