Re: Dangling pointers and incorrect data being written - C / C++ / MFC Discussion Boards

tasumisra14-Dec-08 22:15

14-Dec-08 22:15

Thanks everybody ...

i have Implimented ..Pallini code... its working good for me..
earlier i looped through each character of the string thats was tough
Token concept is good.. Smile | :)

Thank Pallini Smile | :)

vikas da

Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa14-Dec-08 20:02

Mustafa Ismail Mustafa

14-Dec-08 20:02

when you have a method prototype as such:

<code>
void setCacheBlocks(vector<cacheblock> const &value);
</cacheblock></code>

and an implementation as such:

<code>
void Simulator::setCacheBlocks(vector<cacheblock> const & value)
{
m_CacheBlock = value;
}
</cacheblock></code>

And when you run the code, the size of items in the vector is correct, but the actual contents of each object contained by the vector magically disappears?

here's what's actually happening (keep in mind this is a mutation of several generations)

<code>

void Simulator::Simulate()
{
Splash();
getUserSettings();
cout.clear();
cout << "Reading trace file..." << endl;
GetData();
sleep(2);
cout << "\nData read.\nStarting Simulation..." << endl;
sleep(1);

// simulation start
//create the data blocks and the cache sets
//create the Cache Blocks
CreateCacheBlocks();
//create the Cache Sets
CreateCacheSets();
}

void Simulator::CreateCacheBlocks()
{
uint numBlocks = getSettings().getCacheSize()/getSettings().getBlocksSize();

uint maxOffset = getSettings().getOffsetParity();
uint bTag = getSettings().getTagParity();
uint bIndex = getSettings().getIndexParity();
bool isValid = false;
char* bData = new char[maxOffset - 1]; //just to make it 0 based
for(int i = 0; i < maxOffset; i++)
{
bData[i] = NULL;
}

vector<cacheblock> v;

CacheBlock cb;
cb.Initialize(maxOffset,bTag,bIndex,isValid,bData);

cb.setSettings(m_Settings);
//initialize each cache block to an initial state
for(uint i = 0; i < numBlocks; i++)
{
cb.setBlockNumber(i);
cb.setBlockAddress(cb.CalculateBlockAddress(i));
v.push_back(cb);
}
//TODO: fix this ASAP
//setCacheBlocks(v);
m_CacheBlock = v;
}

void Simulator::CreateCacheSets()
{
uint numBlocks = getSettings().getCacheSize()/getSettings().getBlocksSize();
uint numSets = numBlocks/getSettings().getCacheAssociativity();

uint numBlocksPerSet = numBlocks / numSets;

CacheSet cs;
cs.setSettings(getSettings());
vector<cacheset> v;

//create the correct number of sets and assign their set indexes
for(uint i = 0; i < numSets; i++)
{
cs.setSetIndex(i);
v.push_back(cs);
}

int k = v.size();
CacheBlock cb;

//assign each cache block to its set
uint setIx = 0;
for(uint i = 0; i < numBlocks; i++)
{

setIx = getCacheBlocks()[i].getBlockAddress() << getSettings().getTagParity();
setIx >>= getSettings().getTagParity();
//cb = getCacheBlocks()[i];
cb = m_CacheBlock[i]; //this statement should be exactly like the preceding one in worth
v[setIx].getCacheBlocks().push_back(cb);
}

setCacheSet(v);
}

</cacheset></cacheblock></code>

If you look to the method Simulate, everything works fine, including CreateCacheBlocks(), but things go belly up in CreateCacheSets().

Yes, I know I shouldn't be using getXX()/setXX() but this is the second time I've had to deal with this Prof and he's old and really old school and doesn't want to get with the times of using overloaded methods.

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Sig history

"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

Re: Dangling pointers and incorrect data being written

Cedric Moonen14-Dec-08 20:48

Cedric Moonen

14-Dec-08 20:48

Your post is very difficult to read (don't check the "ignore html tags" otherwise the code tags won't work).

You are talking about danling pointers. Where are those pointers because I don't see any pointers in your code...

Mustafa Ismail Mustafa wrote:
And when you run the code, the size of items in the vector is correct, but the actual contents of each object contained by the vector magically disappears?

Could you explain that with a bit more details ? You mean that the contents of all the cacheblock objects stored in your vector are destroyed ? Can you show the details of the cacheblock class ?

Cédric Moonen
Software developer

Charting control [v1.5]
OpenGL game tutorial in C++

Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa14-Dec-08 21:11

Mustafa Ismail Mustafa

14-Dec-08 21:11

Cedric Moonen wrote:
Your post is very difficult to read (don't check the "ignore html tags" otherwise the code tags won't work).

Stuff like vector<xyz> v aren't obvious then.

I assumed there are dangling pointers because the objects have values that are not what they were so its like a temporary value that has disappeared.

Cedric Moonen wrote:
Could you explain that with a bit more details ? You mean that the contents of all the cacheblock objects stored in your vector are destroyed ? Can you show the details of the cacheblock class ?

Precisely.

I'll email them since they're on my Linux VM and for some reason, the bidirectional clipboard just stopped working.

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Sig history

"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

Re: Dangling pointers and incorrect data being written

Stuart Dootson14-Dec-08 21:31

Stuart Dootson

14-Dec-08 21:31

Mustafa Ismail Mustafa wrote:
Stuff like vector<xyz> v aren't obvious then

It's not too difficult to use < and > instead - you're more likely to get an answer if your question's nicely formatted, if only because then people can read it Smile | :)

Mustafa Ismail Mustafa wrote:
I assumed there are dangling pointers because the objects have values that are not what they were so its like a temporary value that has disappeared.

You have no explicit pointers in your code. It's more likely that you have a dangling reference - possibly a reference to a local that disappeared when a function completed?

I presume you've stepped through with the debugger, seeing when the values of the objects change? Setting a data breakpoint can help.

Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa14-Dec-08 21:42

Mustafa Ismail Mustafa

14-Dec-08 21:42

Stuart Dootson wrote:
It's not too difficult to use < and > instead - you're more likely to get an answer if your question's nicely formatted, if only because then people can read it

I did that in the following two postings back to Cedric. I was being lazy I suppose.

Stuart Dootson wrote:
You have no explicit pointers in your code. It's more likely that you have a dangling reference - possibly a reference to a local that disappeared when a function completed?

Aha! Live and re-learn.

Stuart Dootson wrote:
I presume you've stepped through with the debugger, seeing when the values of the objects change? Setting a data breakpoint can help.

Certainly. I program in C# and previously Java. The last time I touched C++ was almost 8 years ago, coupled with what I believe is an extremely lacking IDE (netbeans 6.5) on Linux is proving a pain. Gimme Eclipse or VS any day. This is why I seem to be asking really pathetically sounding questions Smile | :)

I come and post after I've given up and then its a matter of re-learning.

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Sig history

"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

Re: Dangling pointers and incorrect data being written

Stuart Dootson14-Dec-08 22:07

Stuart Dootson

14-Dec-08 22:07

Looking at your code, m_Settings and m_BlockData in CacheBlock are certainly iffy. You copy pointers to these items, but I suspect you should really copy the contents. Especially when (from the Simulator::CreateCacheBlocks code) it looks like all your cache-blocks will be sharing the same block data with your current implementation.

Memory management in C++ certainly can be a pain - that's why I try to always use objects that manage it for you, such as std::vectors or Boost shared pointers/shared arrays[^].

Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa15-Dec-08 1:43

Mustafa Ismail Mustafa

15-Dec-08 1:43

Sorry about the lateness, I had to run out for a few errands.

Sadly Stuart, those are the two I'm not having problems with. Its the rest of the class.

If you'll look below, that's where all the fuss is happening.

I'd like to direct your kind attention to the methods CreateCacheBlocks() and CreateCacheSets() in particular the latter. It is then that the contents of the CacheBlock object retrieved by getCacheBlocks()[i] is incorrect and that is where I'm losing my mind because it was in the preceding function CreateCacheBlocks() that I set the values (correctly I might add).

If you're wondering what this is, its the framework for a cache simulator for my Computer Arch II class at university where after I'm supposed to be simulating different algorithms and trying to make them better through changing one thing or another.

<br />
#ifndef _SIMULATOR_H<br />
#define	_SIMULATOR_H<br />
<br />
/******************************************************************************<br />
*           REMOVE ASAP<br />
******************************************************************************/<br />
#define DEBUG<br />
<br />
#include <iostream><br />
#include <vector><br />
#include "definitions.h"<br />
#include "settings.h"<br />
#include "filereader.h"<br />
#include "cacheset.h"<br />
#include "cacheblock.h"<br />
<br />
<br />
using namespace std;<br />
<br />
class Simulator<br />
{<br />
<br />
public:<br />
    Simulator();<br />
    Simulator(const Simulator& orig);<br />
    virtual ~Simulator();<br />
<br />
    void getUserSettings();<br />
    void GetData();<br />
    void Simulate();<br />
    void Splash();<br />
<br />
    void CreateCacheBlocks();<br />
    void CreateCacheSets();<br />
<br />
    /*settings*/<br />
    Settings getSettings() const;<br />
    void setSettings(Settings const &value);<br />
    <br />
<br />
    /*CacheSet*/<br />
    vector<CacheSet> getCacheSet() const;<br />
    void setCacheSet(vector<CacheSet> const &value);<br />
    <br />
    /*CacheBlocks*/<br />
    vector<CacheBlock> getCacheBlocks() const;<br />
    void setCacheBlocks(vector<CacheBlock> const &value);<br />
<br />
    /*Data Buffer*/<br />
    vector<uint> getDataBuffer() const;<br />
    void setDataBuffer(vector<uint> const &value);<br />
<br />
private:<br />
    Settings m_Settings;;<br />
    //CacheBlock* m_CacheBlock;<br />
    vector<CacheBlock> m_CacheBlock;<br />
    //CacheSet* m_CacheSet;<br />
    vector<CacheSet> m_CacheSet;<br />
    vector<uint> m_DataBuffer;<br />
<br />
};<br />
<br />
#endif	/* _SIMULATOR_H */<br />
</vector></iostream>

***********************************************

<br />
#include "simulator.h"<br />
#include <vector><br />
#include "cacheset.h"<br />
<br />
<br />
Simulator::Simulator()<br />
{<br />
    m_Settings.setAccessesToSimulate(0);<br />
    m_Settings.setBlockSize(0);<br />
    m_Settings.setCacheAssociativity(0);<br />
    m_Settings.setCachePolicy(Settings::LRU);<br />
    m_Settings.setCacheSize(0);<br />
}<br />
<br />
Simulator::Simulator(const Simulator& orig)<br />
{<br />
}<br />
<br />
Simulator::~Simulator()<br />
{<br />
}<br />
<br />
<br />
/*<br />
 ******************************************************************************<br />
 *      Public Methods<br />
 ******************************************************************************<br />
 */<br />
void Simulator::getUserSettings()<br />
{<br />
    #ifdef DEBUG<br />
    Settings s;<br />
    s.setDefault();<br />
    setSettings(s);<br />
<br />
    return;<br />
    #endif<br />
<br />
    //ask the user for the settings<br />
    //TODO: Ask the user for the settings<br />
    <br />
    //TODO: An Associativity of 0 means a Fully Associative cache<br />
}<br />
<br />
void Simulator::GetData()<br />
{<br />
    FileReader fr;<br />
    Settings s;<br />
    s = getSettings();<br />
    setDataBuffer(fr.ReadFile(s));<br />
<br />
}<br />
<br />
<br />
void Simulator::Simulate()<br />
{<br />
    Splash();<br />
<br />
    getUserSettings();<br />
<br />
    cout.clear();<br />
    cout << "Reading trace file..." << endl;<br />
   <br />
    GetData();<br />
    sleep(2);<br />
<br />
    cout << "\nData read.\nStarting Simulation..." << endl;<br />
    sleep(1);<br />
<br />
    // simulation start<br />
<br />
    //create the data blocks and the cache sets<br />
<br />
    //create the Cache Blocks<br />
    CreateCacheBlocks();<br />
<br />
    //create the Cache Sets<br />
    CreateCacheSets();<br />
<br />
}<br />
<br />
void Simulator::CreateCacheBlocks()<br />
{<br />
    //*************************************************************************<br />
    //              DO NOT FORGET, WE'RE USING 32 BIT addressing!             *<br />
    //*************************************************************************<br />
    //              This is because each access is 4 * 8 bits = 32 bits       *<br />
    //But because I'm a good student, I'll still calculate the shifts instead *<br />
    //of simply hardwiring the values.                                        *<br />
    //Steve                                                                   *<br />
    //*************************************************************************<br />
<br />
    uint numBlocks = getSettings().getCacheSize()/getSettings().getBlocksSize();<br />
    <br />
    /*<br />
    uint maxOffset = CalculateMaxOffset();<br />
<br />
    //tag is easily defined as "which data|instruction in the block?"<br />
    uint bTag = CalculateTag(0,maxOffset);<br />
<br />
    //index is easily defined as "which set?"<br />
    uint bIndex = CalculateTag(0, bTag, maxOffset);<br />
    */<br />
<br />
    uint maxOffset = getSettings().getOffsetParity();<br />
    uint bTag = getSettings().getTagParity();<br />
    uint bIndex = getSettings().getIndexParity();<br />
    bool isValid = false;<br />
    char* bData = new char[maxOffset - 1]; //just to make it 0 based<br />
    for(int i = 0; i < maxOffset; i++)<br />
    {<br />
        bData[i] = NULL;<br />
    }<br />
<br />
    <br />
    vector<CacheBlock> v;<br />
    <br />
    CacheBlock cb;<br />
    cb.Initialize(maxOffset,bTag,bIndex,isValid,bData);<br />
    <br />
    cb.setSettings(m_Settings);<br />
    //initialize each cache block to an initial state<br />
    for(uint i = 0; i < numBlocks; i++)<br />
    {<br />
        cb.setBlockNumber(i);<br />
        cb.setBlockAddress(cb.CalculateBlockAddress(i));<br />
        v.push_back(cb);<br />
    }<br />
    //TODO: fix this ASAP<br />
    setCacheBlocks(v);<br />
    //m_CacheBlock = v;<br />
<br />
    #ifdef DEBUG<br />
    cout << "\n\n" << endl;<br />
    cout << "Vector Length: \t" << getCacheBlocks().size() << endl;<br />
<br />
    cout << "\n\n" << endl;<br />
<br />
    for(int i = 0; i < getCacheBlocks().size(); i++)<br />
    {<br />
        cout << "v[" << i << "].BlockAddress = \t" << v[i].getBlockAddress() << endl;<br />
    }<br />
    #endif<br />
}<br />
<br />
void Simulator::CreateCacheSets()<br />
{<br />
    /*the number of cache sets is equal to the<br />
    *       associativity/num blocks<br />
    *and in the case of  a fully associative cache there is only one set<br />
    *and every block belongs to it<br />
     *<br />
     *Create the correct number of cache sets and associate the proper<br />
     *cacheblock to this set<br />
    */<br />
<br />
    uint numBlocks = getSettings().getCacheSize()/getSettings().getBlocksSize();<br />
    uint numSets = numBlocks/getSettings().getCacheAssociativity();<br />
    <br />
    uint numBlocksPerSet = numBlocks / numSets;<br />
<br />
<br />
    CacheSet cs;<br />
    cs.setSettings(getSettings());<br />
    vector<CacheSet> v;<br />
<br />
    //create the correct number of sets and assign their set indexes<br />
    for(uint i = 0; i < numSets; i++)<br />
    {<br />
        cs.setSetIndex(i);<br />
        v.push_back(cs);<br />
    }<br />
<br />
    int k = v.size();<br />
    CacheBlock cb;<br />
<br />
    //assign each cache block to its set<br />
    uint setIx = 0;<br />
    for(uint i = 0; i < numBlocks; i++)<br />
    {<br />
        <br />
        setIx = getCacheBlocks()[i].getBlockAddress() << getSettings().getTagParity();<br />
        setIx >>= getSettings().getTagParity();<br />
        //cb = getCacheBlocks()[i];<br />
        cb = m_CacheBlock[i];<br />
        v[setIx].getCacheBlocks().push_back(cb);<br />
    }<br />
<br />
    #ifdef DEBUG<br />
    int j = v.size();<br />
<br />
    for(int i = 0; i < v.size(); i++)<br />
    {<br />
        j = v[i].getCacheBlocks().size();<br />
        cout << "V[i][j].size() =" << j << endl;<br />
    }<br />
    #endif<br />
<br />
    setCacheSet(v);<br />
<br />
    #ifdef DEBUG<br />
    /*<br />
    cout << "\n" << endl;<br />
    cout << "Number of Sets:\t\t" << getCacheSet().size() << endl;<br />
    cout << "Number of blocks in each set:\t" <<<br />
        getCacheSet()[0].getCacheBlocks().size() << endl;<br />
    cout << "\n" << endl;<br />
    for(int i = 0; i < getCacheSet().size(); i++)<br />
    {<br />
        cout << "Cache set:\t" << i << endl;<br />
        cout << "\n" << endl;<br />
        for(int j = 0; j < getCacheSet()[i].getCacheBlocks().size(); j++)<br />
        {<br />
            cout << "Block number " << j << "\tBlock Address: " << getCacheSet()[i].getCacheBlocks()[i].getBlockAddress();<br />
        }<br />
        cout << "\n" << endl;<br />
    }<br />
    */<br />
    cout << "\n" << endl;<br />
    cout << "Number of Sets:\t\t" << v.size() << endl;<br />
    cout << "Number of blocks in each set:\t" <<<br />
        v[0].getCacheBlocks().size() << endl;<br />
    cout << "\n" << endl;<br />
    for(int i = 0; i < v.size(); i++)<br />
    {<br />
        cout << "Cache set:\t" << i << endl;<br />
        cout << "\n" << endl;<br />
        for(int j = 0; j < v[i].getCacheBlocks().size(); j++)<br />
        {<br />
            cout << "Block number " << j << "\tBlock Address: " << v[i].getCacheBlocks()[i].getBlockAddress();<br />
        }<br />
        cout << "\n" << endl;<br />
    }<br />
    #endif<br />
<br />
}<br />
<br />
<br />
<br />
void Simulator::Splash()<br />
{<br />
    cout.clear();<br />
<br />
    cout << "Starting Cache Simulation by Steve Mustafa\n\n" << endl;<br />
    cout << "Supervisor: Dr. Mazen Kharbutli\nComputer Architecture II\n" << endl;<br />
<br />
    //wait for 5 seconds<br />
    sleep(5);<br />
}<br />
<br />
/*Methods for Properties*/<br />
<br />
/*Settings*/<br />
Settings Simulator::getSettings() const<br />
{<br />
    return m_Settings;<br />
}<br />
<br />
<br />
void Simulator::setSettings(Settings const &value)<br />
{<br />
    m_Settings = value;<br />
}<br />
<br />
/*Cache Set*/<br />
vector<CacheSet> Simulator::getCacheSet() const<br />
{<br />
    return m_CacheSet;<br />
}<br />
<br />
void Simulator::setCacheSet(vector<CacheSet>const &value)<br />
{<br />
    <br />
    int j = m_CacheSet.size();<br />
    m_CacheSet = value;<br />
    j = m_CacheSet.size();<br />
    j = getCacheSet().size();<br />
}<br />
<br />
/*Cache Blocks*/<br />
vector<CacheBlock> Simulator::getCacheBlocks() const<br />
{<br />
    return m_CacheBlock;<br />
}<br />
<br />
void Simulator::setCacheBlocks(vector<CacheBlock> const & value)<br />
{<br />
    m_CacheBlock = value;<br />
    int j = m_CacheBlock.size();<br />
    j = getCacheBlocks().size();<br />
}<br />
<br />
/* Data Buffer */<br />
vector<uint> Simulator::getDataBuffer() const<br />
{<br />
    return m_DataBuffer;<br />
}<br />
<br />
void Simulator::setDataBuffer(vector<uint> const &value)<br />
{<br />
    m_DataBuffer = value;<br />
}<br />

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"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

Re: Dangling pointers and incorrect data being written

Stuart Dootson15-Dec-08 13:37

Stuart Dootson

15-Dec-08 13:37

I'm a f**king idiot. I've built your code and stepped through it with GDB (well, Xcode on my Mac) and just realised what the problem is, when it should have been immediately obvious.

The trouble is your copy constructors - they're not doing anything! Which means that as they're used when copying items into a vector using push_back, the vector gets set with empty items.

Anyway - you can rely on the default copy constructor and assignment operator if member-wise copy is adequate for your structure. Member-wise is fine unless you need to do some sort of resource management (e.g. memory allocation/deallocation).

Hope that sorts you out!

Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa16-Dec-08 18:21

Mustafa Ismail Mustafa

16-Dec-08 18:21

OK, firstly, Stu, let me just say thank you for being so patient in helping me solve this continuing issue. Your patience is model.

Secondly, I have discovered another problem and I've easily spent 4 hours on it trying to figure out how the hell its happening. Really, in the class "Simulator" even though we have

<br />
vector<cacheset> getCacheSet() const;<br />
void setCacheSet(vector<cacheset> const & value);<br />
<br />
vector<cacheblock> getCacheBlock() const;<br />
void setCacheBlock(vector<cacheblock> const & value);<br />
</cacheblock></cacheblock></cacheset></cacheset>

the actions are local to that subroutine (I'm looking at CreateCacheBlocks() and CreateCacheSets()) and are not acting on the class instance. Ultimately, the question is why? How can I be moving in a proper functional sequence in 2 different instances? What the hell am I forgetting?

I've implemented the copy constructors for the CacheSet and CacheBlock classes as you've suggested and they've alleviated the previous problems, but somehow, I get the feeling that the current issue I'm facing is a continuation of the previous one.

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Sig history

"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

Re: Dangling pointers and incorrect data being written

Stuart Dootson16-Dec-08 19:40

Stuart Dootson

16-Dec-08 19:40

Mustafa Ismail Mustafa wrote:
the actions are local to that subroutine (I'm looking at CreateCacheBlocks() and CreateCacheSets()) and are not acting on the class instance. Ultimately, the question is why? How can I be moving in a proper functional sequence in 2 different instances? What the hell am I forgetting?

Not really sure what you mean - what are you seeing vs what would you expect to see?

Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa16-Dec-08 19:50

Mustafa Ismail Mustafa

16-Dec-08 19:50

Basically, when I'm calling CreateCacheBlocks() I'm creating a vector of CacheBlock objects, initialized to whatever initial values it should have determined by user input previously acquired in the application (currently simply defaulting it). CreateCacheSets() is supposed to create a number of sets (dependent on the associativity selected) after which, it assigns specific CacheBlocks to each set (basic Cache and Cache Associativity).

What I've noticed is that CreateCacheBlocks() creates the vector and its contents correctly and I've checked this at the end of the method and as soon as I exit the method back to the method Simulate, however, when the call to CreateCacheSets is made, the vector CacheBlocks is empty. How the hell did that happen?

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"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

Re: Dangling pointers and incorrect data being written

Stuart Dootson16-Dec-08 21:52

Stuart Dootson

16-Dec-08 21:52

That still sounds like copy constructor or assignment operator issues - could you post the code for those that you've now implemented?

Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa16-Dec-08 23:50

Mustafa Ismail Mustafa

16-Dec-08 23:50

Sorry this took some time, my system just crashed and I spent the last hour just restoring order.

Here's the Copy Constructors:

<br />
CacheSet(const CacheSet& orig);  //Header<br />
<br />
CacheSet::CacheSet(const CacheSet& orig)  //CPP<br />
{<br />
    setSettings(orig.getSettings());<br />
    setBlockCount(orig.getBlockCount());<br />
    setBlockSize(orig.getBlockSize());<br />
    setSetIndex(orig.getSetIndex());<br />
    setCacheBlocks(orig.getCacheBlocks());<br />
}<br />

<br />
CacheBlock(const CacheBlock& orig); //Header<br />
<br />
CacheBlock::CacheBlock(const CacheBlock& orig) //CPP<br />
{<br />
    setSettings(orig.getSettings());<br />
    setBlockAddress(orig.getBlockAddress());<br />
    setBlockData(orig.getBlockData());<br />
    setBlockIndex(orig.getBlockIndex());<br />
    setBlockTag(orig.getBlockTag());<br />
    setBlockNumber(orig.getBlockNumber());<br />
    setIsValid(orig.getIsValid());<br />
    setMaxBlockOffset(orig.getMaxBlockOffset());<br />
    setTimeStamp(orig.getTimeStamp());<br />
}<br />

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"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

Re: Dangling pointers and incorrect data being written

Stuart Dootson17-Dec-08 2:34

Stuart Dootson

17-Dec-08 2:34

Mmmm - I'm not seeing what you're seeing - m_CacheBlocks retains its value. However, I've found some more issues in your code:

getCacheBlocks returns the cache-block vector by value - try returning by const reference instead:
```
vector<CacheBlock> const & getCacheBlocks() const;
```
Some of your setter functions take a uint by non-const reference - they should probably be by value (that's fine with plain old data like integers) or const reference. VC++ complained about it, anyway.

Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa17-Dec-08 4:47

Mustafa Ismail Mustafa

17-Dec-08 4:47

I have taken your advice and currently have given up developing on Linux, I can't make good use of my time using IDEs that I don't have much experience in and on top of that using a language that I obviously am completely out of practice with (MUCH more so than I thought Cry | :((

)

I've moved back to Windows (VS2008) at least the debugger is something of an old friend. I'll keep you posted mate.

Thanks a zillion.

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"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

Re: Dangling pointers and incorrect data being written

Stuart Dootson17-Dec-08 5:18

Stuart Dootson

17-Dec-08 5:18

Mustafa Ismail Mustafa wrote:
I've moved back to Windows (VS2008) at least the debugger is something of an old friend

Can't say I blame you - even using GDB through Xcode felt...strange, given how used to Visual Studio I am!

Re: Dangling pointers and incorrect data being written [modified]

Mustafa Ismail Mustafa17-Dec-08 5:52

Mustafa Ismail Mustafa

17-Dec-08 5:52

I've pinpointed the exact location where the error takes place.

Guess what? Its a const correctness issue.

Simulator::CreateCacheSets()
{
...
getCacheSets[setIx].getCacheBlocks().push_back(getCacheBlocks()[i]);
...
}

getCacheBlocks() returns a const object. I'm surprised a compile time error was not thrown. Do I overload the method?

[update]
I've fixed it, but its the ugliest hack I've ever done.

<br />
//v[setIx].getCacheBlocks().push_back(getCacheBlocks()[i]);<br />
/*<br />
Can't do it this way, the getCacheBlocksMethod is const, so, we're doing it the crappy way<br />
which is making equivalent objects and setting them<br />
*/<br />
    vector<cacheblock> cbs;<br />
    for(uint i = 0; i < numBlocks; i++)<br />
    {<br />
        ba = getCacheBlocks()[i].getBlockAddress();<br />
        setIx = ba % numSets;<br />
        cbs = v[setIx].getCacheBlocks();<br />
	cbs.push_back(this->getCacheBlocks()[i]);<br />
	v[setIx].setCacheBlocks(cbs);<br />
    }<br />
</cacheblock>

Just sick and as ugly as sin.

Stuart, thanks a million mate for all your patience. When I do pass by Brittania, an hour's worth of pints is on me Smile | :)

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"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

modified on Wednesday, December 17, 2008 12:14 PM

Re: Dangling pointers and incorrect data being written

Stuart Dootson17-Dec-08 6:25

Stuart Dootson

17-Dec-08 6:25

Mustafa Ismail Mustafa wrote:
Do I overload the method

You can't overload purely on return type - in C++ (unlike Ada), function signatures don't include return types.

I may have given you some bad advice suggesting you return by const reference - a non-const reference would be better in this case.

Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa17-Dec-08 6:35

Mustafa Ismail Mustafa

17-Dec-08 6:35

I won't judge.

It has become so obvious (to me) that I've been living a life of decadence between Java and C#. I need to rough it up. From now on, all University projects will be in C++.

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"dad" Ishmail-Samuel Mustafa

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Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa14-Dec-08 21:12

Mustafa Ismail Mustafa

14-Dec-08 21:12

I realized I don't have your address. I'll email them to myself and post here.

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"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa14-Dec-08 21:26

Mustafa Ismail Mustafa

14-Dec-08 21:26

Here they are:

<br />
CacheBlock:<br />
<br />
/* <br />
 * File:   cacheblock.h<br />
 * Author: Steve<br />
 *<br />
 * Created on December 9, 2008, 2:44 PM<br />
 */<br />
<br />
#ifndef _CACHEBLOCK_H<br />
#define	_CACHEBLOCK_H<br />
<br />
#include <time.h><br />
#include "definitions.h"<br />
#include "settings.h"<br />
<br />
using namespace std;<br />
<br />
class CacheBlock<br />
{<br />
<br />
public:<br />
    CacheBlock();<br />
    CacheBlock(const CacheBlock& orig);<br />
    CacheBlock(int maxOffset, uint bTag, uint bIndex,<br />
               bool isValid, char* bData);<br />
    virtual ~CacheBlock();<br />
<br />
    //Block Offset<br />
    int getMaxBlockOffset() const;<br />
    void setMaxBlockOffset(int const &value);<br />
<br />
    //block tag<br />
    uint  getBlockTag() const;<br />
    void setBlockTag(uint &value);<br />
<br />
    //block index<br />
    uint getBlockIndex() const;<br />
    void setBlockIndex(uint & value);<br />
<br />
    //Is Valid<br />
    bool getIsValid() const;<br />
    void setIsValid(bool const &value);<br />
<br />
    //Block Data - Complete block (offsets 0 - max)<br />
    char* getBlockData() const;<br />
    void setBlockData(char* const &value);<br />
<br />
    //Block Data Item<br />
    char getBlockDataItem(int &offset) const;<br />
    void setBlockDataItem(int const &offset,char const &value);<br />
<br />
    //Time Stamp<br />
    time_t getTimeStamp() const;<br />
    void setTimeStamp(time_t const  &value);<br />
<br />
    //Initializaton<br />
    void Initialize(int maxOffset, uint bTag,<br />
                    uint bIndex, bool isValid, char* bData);<br />
<br />
    //block number<br />
    uint getBlockNumber() const;<br />
    void setBlockNumber(uint const &value);<br />
<br />
    //block Address<br />
    uint getBlockAddress() const;<br />
    void setBlockAddress(uint const &value);<br />
<br />
    /*Calculate the Block address from the memory address*/<br />
    uint CalculateBlockAddress(uint const &memoryAddress) const;<br />
<br />
    //Settings<br />
    Settings* getSettings() const;<br />
    void setSettings(Settings &value);<br />
private:<br />
<br />
    int m_MaxBlockOffset;<br />
    uint m_BlockTag;<br />
    uint m_BlockIndex;<br />
    char* m_BlockData;<br />
    time_t m_Timestamp;<br />
    bool m_IsValid;<br />
    uint m_BlockNumber;<br />
    uint m_BlockAddress;<br />
    Settings* m_Settings;<br />
};<br />
<br />
#endif	/* _CACHEBLOCK_H */<br />
<br />
/* <br />
 * File:   cacheblock.cpp<br />
 * Author: Steve<br />
 * <br />
 * Created on December 9, 2008, 2:44 PM<br />
 */<br />
<br />
#include "cacheblock.h"<br />
<br />
CacheBlock::CacheBlock()<br />
{}<br />
<br />
CacheBlock::CacheBlock(const CacheBlock& orig)<br />
{<br />
}<br />
<br />
CacheBlock::CacheBlock(int maxOffset, uint bTag,<br />
                       uint bIndex, bool isValid, char* bData)<br />
{<br />
    setMaxBlockOffset(maxOffset);<br />
    setBlockTag(bTag);<br />
    setBlockIndex(bIndex);<br />
    setIsValid(isValid);<br />
    setBlockData(bData);<br />
}<br />
<br />
CacheBlock::~CacheBlock()<br />
{}<br />
<br />
/* Block Index */<br />
uint CacheBlock::getBlockIndex() const<br />
{<br />
    return m_BlockIndex;<br />
}<br />
<br />
void CacheBlock::setBlockIndex(uint &value )<br />
{<br />
    m_BlockIndex = value;<br />
}<br />
<br />
/*Block Tag*/<br />
uint CacheBlock::getBlockTag() const<br />
{<br />
    return m_BlockTag;<br />
}<br />
<br />
void CacheBlock::setBlockTag(uint  &value)<br />
{<br />
    m_BlockTag = value;<br />
}<br />
<br />
/*Block Data*/<br />
char* CacheBlock::getBlockData() const<br />
{<br />
    return m_BlockData;<br />
}<br />
<br />
void CacheBlock::setBlockData(char* const &value)<br />
{<br />
    m_BlockData = value;<br />
}<br />
<br />
/*Is Valid*/<br />
bool CacheBlock::getIsValid() const<br />
{<br />
    return m_IsValid;<br />
}<br />
<br />
void CacheBlock::setIsValid(bool  const &value)<br />
{<br />
    m_IsValid = value;<br />
}<br />
<br />
/*Block Data Item*/<br />
char CacheBlock::getBlockDataItem(int &offset) const<br />
{<br />
    return getBlockData()[offset];<br />
}<br />
<br />
void CacheBlock::setBlockDataItem(int const &offset, char const &value)<br />
{<br />
    getBlockData()[offset] = value;<br />
}<br />
<br />
/*Max Block Offset (which is the length of the data array*/<br />
int CacheBlock::getMaxBlockOffset() const<br />
{<br />
    return m_MaxBlockOffset;<br />
}<br />
<br />
void CacheBlock::setMaxBlockOffset(int const &value)<br />
{<br />
    m_MaxBlockOffset = value;<br />
}<br />
<br />
<br />
/*Timestamp*/<br />
time_t CacheBlock::getTimeStamp() const<br />
{<br />
    return m_Timestamp;<br />
}<br />
<br />
void CacheBlock::setTimeStamp(time_t const &value)<br />
{<br />
    m_Timestamp = value;<br />
}<br />
<br />
/*Initialize*/<br />
void CacheBlock::Initialize(int maxOffset, uint bTag,<br />
                       uint bIndex, bool isValid, char* bData)<br />
{<br />
    setMaxBlockOffset(maxOffset);<br />
    setBlockTag(bTag);<br />
    setBlockIndex(bIndex);<br />
    setIsValid(isValid);<br />
    setBlockData(bData);<br />
    setTimeStamp(time(0));<br />
}<br />
<br />
/*Block Number*/<br />
uint CacheBlock::getBlockNumber() const<br />
{<br />
    return m_BlockNumber;<br />
}<br />
<br />
void CacheBlock::setBlockNumber(uint const &value)<br />
{<br />
    m_BlockNumber = value;<br />
}<br />
<br />
/*Block Address*/<br />
uint CacheBlock::getBlockAddress() const<br />
{<br />
    return m_BlockAddress;<br />
}<br />
<br />
void CacheBlock::setBlockAddress(uint const &value)<br />
{<br />
    m_BlockAddress = value;<br />
}<br />
<br />
uint  CacheBlock::CalculateBlockAddress(uint const &memoryAddress) const<br />
{<br />
    //the block address is the memory address, less the offset bits<br />
<br />
    uint ma = memoryAddress >> getSettings()->getOffsetParity();<br />
    return ma;<br />
}<br />
<br />
Settings* CacheBlock::getSettings() const<br />
{<br />
    return m_Settings;<br />
}<br />
<br />
void CacheBlock::setSettings(Settings &value)<br />
{<br />
    m_Settings = &value;<br />
}<br />
<br />
<br />
CacheSet:<br />
<br />
/* <br />
 * File:   cacheset.h<br />
 * Author: Steve<br />
 *<br />
 * Created on December 9, 2008, 3:28 PM<br />
 */<br />
<br />
#ifndef _CACHESET_H<br />
#define	_CACHESET_H<br />
<br />
#include "definitions.h"<br />
#include "settings.h"<br />
#include "cacheblock.h"<br />
<br />
class CacheSet<br />
{<br />
<br />
public:<br />
    CacheSet();<br />
    CacheSet(const CacheSet& orig);<br />
    CacheSet(int setIndex, int bCount, Settings const &settings);<br />
    virtual ~CacheSet();<br />
<br />
    /*Block Count*/<br />
    int getBlockCount() const;<br />
    void setBlockCount(int const &value);<br />
    <br />
    /*Set Index*/<br />
    int getSetIndex() const;<br />
    void setSetIndex(int const & value);<br />
    <br />
    /*Block Size*/<br />
    int getBlockSize() const ;<br />
    void setBlockSize(int const &value);<br />
    <br />
    /*CacheBlocks*/<br />
    vector<cacheblock> getCacheBlocks() const;<br />
    void setCacheBlocks(vector<CacheBlock> const &value);<br />
    <br />
    /*Settings*/<br />
    Settings getSettings() const;<br />
    void setSettings(Settings const &value);<br />
    <br />
private:<br />
    int m_BlockCount;<br />
    vector<CacheBlock> m_CacheBlocks;<br />
    int m_SetIndex;<br />
    int m_BlockSize;<br />
    Settings m_Settings;<br />
};<br />
<br />
#endif	/* _CACHESET_H */<br />
<br />
<br />
/* <br />
 * File:   cacheset.cpp<br />
 * Author: Steve<br />
 * <br />
 * Created on December 9, 2008, 3:28 PM<br />
 */<br />
<br />
#include "cacheset.h"<br />
<br />
CacheSet::CacheSet()<br />
{<br />
}<br />
<br />
CacheSet::CacheSet(const CacheSet& orig)<br />
{<br />
}<br />
<br />
CacheSet::CacheSet(int setIndex, int bCount, Settings const &settings)<br />
{<br />
    setBlockCount(bCount);<br />
    setSettings(settings);<br />
    setSetIndex(setIndex);<br />
<br />
    //initialize the CacheBlocks array<br />
    //setCacheBlocks() = new CacheBlock[bCount];<br />
    //setBlockSize(getSettings()->getBlocksSize());<br />
<br />
}<br />
<br />
CacheSet::~CacheSet()<br />
{<br />
}<br />
<br />
/*Block Size*/<br />
int CacheSet::getBlockSize() const<br />
{<br />
    return m_BlockSize;<br />
}<br />
<br />
void CacheSet::setBlockSize(int const & value)<br />
{<br />
    m_BlockSize = value;<br />
}<br />
<br />
/*Block Count*/<br />
int CacheSet::getBlockCount()const<br />
{<br />
    return m_BlockCount;<br />
}<br />
<br />
void CacheSet::setBlockCount(int const &value)<br />
{<br />
    m_BlockCount = value;<br />
}<br />
<br />
<br />
/*Cache Blocks*/<br />
vector<CacheBlock> CacheSet::getCacheBlocks() const<br />
{<br />
    return m_CacheBlocks;<br />
}<br />
<br />
void CacheSet::setCacheBlocks(vector<CacheBlock> const & value)<br />
{<br />
    m_CacheBlocks = value;<br />
}<br />
<br />
/*Settings*/<br />
Settings CacheSet::getSettings() const<br />
{<br />
    return m_Settings;<br />
}<br />
<br />
void CacheSet::setSettings(Settings const &value)<br />
{<br />
    m_Settings = value;<br />
}<br />
<br />
/*Set Index*/<br />
int CacheSet::getSetIndex() const<br />
{<br />
    return m_SetIndex;<br />
}<br />
<br />
void CacheSet::setSetIndex(int const &value)<br />
{<br />
    m_SetIndex = value;<br />
}<br />
<br />
</cacheblock>

I might have missed an angle bracket or two...

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"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

Develop CSP in XP

izyani14-Dec-08 19:48

izyani

14-Dec-08 19:48

I'm currently done with the source code.

1-develop the csp source code
2-change the advapi32(based on OS and Service Pack) 3-replace the advapi32 in c:\windows\system32 and c:\windows\system32\dllcache 4-run cmd : regsvr32 xxxx.dll 5-test the program

But, in my case, whenever I try to run cmd : regsvr32 xxxx.dll, I will always get the error msg :
DllRegisterServer in xxxx.dll failed. Return code was: 0x80090006.

FYI, I replace all the value for advapi32.dll from the website (change the offset).
I replace the advapi32.dll by following the step:
1-For WIN XP SP3, I replace the advapi32.dll by running in Safe Mode, rename the current advapi32.dll to advapi32.bak, paste the new file there.

Is there anything that I forgot?

Using Queue Timers......

shaina223114-Dec-08 19:22

shaina2231

14-Dec-08 19:22

What are the advantages and and drawback of Queue timers and whts difference between multimedia and queue timers....

Re: Using Queue Timers......

Sarath C15-Dec-08 2:16

Sarath C

15-Dec-08 2:16

I believe the precision is the difference between these two. With Queue Timers you can only give timer resolution upto milliseconds. but Multimedia timers supports high resolution timer (may be in nano secs) supported by the hardware platform(Similar to QueryPerformanceCounter ).

MM Timer[^]
http://msdn.microsoft.com/en-us/library/ms704986(VS.85).aspx
[^]MM Timer Wrapper[^]
http://msdn.microsoft.com/en-us/library/ms682485(VS.85).aspx
[^]

-Sarath.
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