Estring

[Ryumaster]

Hi, edgelib! I've just notice, there is new EString class. I really can't imagine, how it works. Before this I used StrCpy to copy some text into variable.
Lets say, it was:

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1  2  3	ClassEStd::StrCpy(drawtext, "Start Game"); buffer->DrawFont(buffer->GetWidth() / 2, ypos, &shared->font, drawtext, EFX_COLORKEY | EFX_COLORIZE | EFO_HCENTER, textcolor);
	3 lines; 0 keywds; 1 nums; 26 ops; 1 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

Now, how would this part of code look like using EString? maybe my question is sort of stupid, but I just wanna know. because "Also, it will handle memory allocation and protection automatically." attracts me a lot.

[edge]

Hi Ryumaster,

You can create new EString objects, and cast them to WCHAR when using them as a parameter to functions. For example:

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1  2	EString test("hello"); ClassEConsole::MsgWindow((WCHAR *)test);
	2 lines; 0 keywds; 0 nums; 11 ops; 1 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

You can even add strings and do more complicated things like:

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1	ClassEConsole::MsgWindow((WCHAR *)(EString("hello") + "world"));
	1 lines; 0 keywds; 0 nums; 13 ops; 2 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

This creates a new string object, adds another string and casts it to WCHAR.

[Ryumaster]

WOW! That is great! Looks like now I can add cool effects to my dialogs system. I'll take a look on it for sure.

[Zalo]

Hi, Edge I have noticed some problems with this class.

The declaration of operator= with EString as parameter is like this

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1	EString &operator=(EString &str)
	1 lines; 1 keywds; 0 nums; 5 ops; 0 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

instead of

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1	EString &operator=(const EString &str)
	1 lines; 2 keywds; 0 nums; 5 ops; 0 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

I don't understand why, because the othe two options (with char* and WCHAR*) receive this param as const.

The problem is that I have implemented a Vector class, similar to std::vector, and I have instantiated a Vector< EString >. I can't add an element to this vector because internally my vector calls to operator= wich receives a const &EString param.

If you try something like

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1  2  3	const MenuItem m1; MenuItem m2; m2 = m1;
	3 lines; 1 keywds; 0 nums; 4 ops; 0 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

you'll see it doesn't compile because of that operator=. Can you change it?

[Ryumaster]

Btw, EString worked great for me in many cases. But if I supply it as base for filename ( I used WCHAR filename[25] before), I get heap corruption errors. That is not a problem for me, cause I'm using WCHAR for filenames, but just in case You did not know.

[edge]

Zalo:
The non-const parameter was the cause of an internal issue. The parameter will be constant in the next release.

Ryumaster:
It's odd that the heap corruption issues only occur with files. Could you try the following test (here it works correctly)?

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1  2  3  4  5  6  7  8  9	ClassEFile ef; if (ef.Open((WCHAR *)(EString(ecd.dat->currentpath) + "test.txt") , EFOF_READ)) {     char filetext[512];     ef.Read(filetext, ef.Size());     filetext[ef.Size()] = 0;     ClassEConsole::MsgWindow(filetext);     ef.Close(); }
	9 lines; 2 keywds; 2 nums; 47 ops; 1 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

[Zalo]

There is also a problem with the operators. It seems that

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1  2  3	EString &operator+(const char *str) EString &operator+(const WCHAR *str) EString &operator+(const EString &str)
	3 lines; 7 keywds; 0 nums; 15 ops; 0 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

Are changing the internal value of the object EString when this task in C++ is always delegated to operator+=.
Something like this

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1	str = str + c;
	1 lines; 0 keywds; 0 nums; 3 ops; 0 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

compiles but thows an exception an instead I have to write

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1	str + c;
	1 lines; 0 keywds; 0 nums; 2 ops; 0 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

wich looks pretty weird for me

[edge]

Hi Zalo,

Can you tell me if the issue still occurs with the latest EDGELIB (version 3.60)?

This test here works without any problems:

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1  2  3  4  5  6  7  8  9	//Callback: Called before the display mode changes ERESULT ClassMain::OnInit(ENATIVETYPE instance) {     EString str = "hello";     EString c = "world";     str = str + c;     ClassEConsole::MsgWindow((WCHAR *)str);     return(E_OK); }
	9 lines; 1 keywds; 0 nums; 24 ops; 2 strs; 1 coms    Syntactic Coloring v0.4 - Dan East

[Zalo]

Hi, Edge.

It is working fine now. But I still think that operator+ shouldn't modify anything. If you write

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1	str2 = str1 + c;
	1 lines; 0 keywds; 0 nums; 3 ops; 0 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

both str2 and str1 are modified

[Zalo]

Hi, again ^_^

I have a new problem with this class. I have an EString and I am trying to clear it. Something like this:

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1  2	EString str1 = "ABCDEF"; str1 = "";
	2 lines; 0 keywds; 0 nums; 4 ops; 2 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

The value for str1 after that is still "ABCDEF". This only happens with "". If I assign " " everything is ok

[edge]

Hi Zalo,

To temporary fix the empty string assignment problem, we recommend using EString::Trunc to make it empty. We will investigate the other issue with operator+.

[Zalo]

Hello, Edge.

I have just updated to the new version (3.60) There is a bug using Series 60 3rd edition when trying to initilize an EString like this:

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1	EString str = "Hello world";
	1 lines; 0 keywds; 0 nums; 2 ops; 1 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

When I try to compile this with EDGELIB builder I get:

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1  2  3  4  5  6

helloworld.cpp: In member function `virtual long int ClassMain::OnDisplayInit(int, ClassEDisplay*)': helloworld.cpp:90: error: no matching function for call to `EString::EString(EString)' C://Develop//Edge//Edge//include/extapi/dataapi.h:70: note: candidates are: EString::EString(EString&) C://Develop//Edge//Edge//include/extapi/dataapi.h:69: note:                 EString::EString(const short unsigned int*) C://Develop//Edge//Edge//include/extapi/dataapi.h:68: note:                 EString::EString(const char*) helloworld.cpp:90: error:   initializing temporary from result of `EString::EString(const char*)'

6 lines; 6 keywds; 2 nums; 29 ops; 0 strs; 3 coms    Syntactic Coloring v0.4 - Dan East

It is only happening with series 60 3rd edition. I can compile for pocket pc and series 60 1st edition without any problem. For Series 60 3rd edition I have to write the previous code like this:

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1	EString str("Hello world");
	1 lines; 0 keywds; 0 nums; 3 ops; 1 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

[edge]

Hi Zalo,

We've changed the constructor parameter to a const EString, instead of a normal EString. This will fix the compiler issue on Series 60 third edition. It will be available in the next release.

[Freddy]

I stumbled on these bugs while using EString as well. Any ETA when the modifiying of s2 in s1=s2+"test" and the s1="" will be fixed?

I also noticed Get() does not returns a const like it should. I wanted to store an EString into EFile and figured I had to use GetDataSize(), but for "test" it returns 5 (4+0-terminated, or 1-byte length indicator+4 chars?). This forced me to make a work-around like this:

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1  2  3	unsigned char iSize=(unsigned char)(sStr.Length()*sizeof(WCHAR)); ef.Write(&iSize,sizeof(iSize)); ef.Write(sStr.Get(),iSize);
	3 lines; 6 keywds; 0 nums; 28 ops; 0 strs; 0 coms    Syntactic Coloring v0.4 - Dan East

(For strings below 128 chars)


For reading from files I had to use:

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1  2  3  4  5  6  7  8  9  10	unsigned char iSize=0; ef.Read(&iSize,sizeof(iSize)); WCHAR chr; /* bugfix since sStr="" does not work    http://www.pocketmatrix.com/forums/viewtopic.php?t=28434 :*/ sStr.Trunc(0); for(unsigned char i=0;i<iSize;i+=sizeof(WCHAR)) {   ef.Read(&chr,sizeof(WCHAR));   sStr.CatChr(chr); }
	10 lines; 8 keywds; 3 nums; 39 ops; 0 strs; 1 coms    Syntactic Coloring v0.4 - Dan East

Alternatives would be appreciated

[edge]

Hi Freddy,

Fixes for EString will probably be added in the EDGELIB 3.70 release.

For reading the EString value from a file we recommend allocating memory temporarily and read in the whole string at once.