[RESOLVED] Stack Overflow

[Mogulbasher]

Ok, it seems I have made a beginners error. I have the following structures defined in my h file

typedef struct {
	unsigned char	B;
	unsigned char	G;
	unsigned char	R;
	unsigned char	A;
} pix32;

struct FinalTGAFile
{
	char    IDLen;         //length of ID field
	char    MapType;       //0=none, 1=present
	char    ImgType;       //0=none, 1=c-map, 2=true, 
	short   FirstColor;    //where to start in colormap
	short   MapLen;        //number of colors to set
	char    EntrySize;     //number of bits per color entry
	short   Xorigin;
	short   Width;
	short   Height;
	char    Depth;
	char    Descriptor;
	pix32  Pixel[];
};

The cpp code extract is as follows

//Create a new TGA header
FinalTGAFile tgaCell;
memset(&tgaCell,0, 18);
tgaCell.ImgType = 2;//true-color
tgaCell.Height = 100;
tgaCell.Width = 4800;
tgaCell.Depth = 32;//has alpha
tgaCell.Descriptor = 32;

//extract of code that moves the pixels around
int j=0;
int p;
int count=0;
for(int y=0; y<100;y++)
{
	if(y<256)
	{
		int j=y*1024;
		for(int h=0;h<18;h++)
		{
			
		for (p=j; p<j+1024;p=p+4)
		{
		//Eventually this will bomb out when count gets too large		
		tgaCell.Pixel[count].B = final].finalimage[p];
		tgaCell.Pixel[count].G = final[h].finalimage[p+1];
		tgaCell.Pixel[count].R = final[h].finalimage[p+2];
		tgaCell.Pixel[count].A = final[h].finalimage[p+3];
		count++;

I then basically take a whole series of tga files and stitch them together by filling up the pix32 structure with pixels.

Based on reading I have done it appears this is because this array is getting put on the stack (rather than heap) and so at some point in time it is larger than the max allowed memory.

However I am unsure of the method used to allocate this to the heap using the structures I have created. Can someone please provide some guidance on how to best do this..

Regards, Andrew

[GCDEF]

FinalTGAFile* tgaCell = new FinalTGAFile;

[Mogulbasher]

First of all thanks for replying...

Replacing

FinalTGAFile tgaCell;

with

FinalTGAFile* tgaCell = new FinalTGAFile;

renders all my code using for example tgaCell.ImgType invalid as left of '.ImgType' must have class/struct/union

In this situation would I have to use tgaCell->ImgType?

Or is there something else I should do...

PS If I do this....

following the call to the new FinalTGAFile gives the following error at
tgaCell->ImgType = 2;

Unhandled exception at 0x004212bf in Links Extender.exe: 0xC0000005: Access violation writing location 0x00000002

[Paul McKenzie]

pix32  Pixel[];

What compiler allows this? This is illegal C++.

Regards,

Paul McKenzie

[Skizmo]

In this situation would I have to use tgaCell->ImgType?

yes. . it's a pointer now .. so you have to use '->'.

btw : don't forget do delete tgaCell when you're done with it.

[Skizmo]

Unhandled exception at 0x004212bf in Links Extender.exe: 0xC0000005: Access violation writing location 0x00000002

memset(&tgaCell,0, 18);

tgaCell is a pointer now.

FinalTGAFile* tgaCell = new FinalTGAFile;
memset(tgaCell, 0, 18);

[Mogulbasher]

pix32  Pixel[];

What compiler allows this? This is illegal C++.

Regards,

Paul McKenzie

VS2005 allowed it... I changed it to [1536000]

[Mogulbasher]

Great worked a treat, thank you very much

Amdrew

[Paul McKenzie]

VS2005 allowed it...

If it's a compiler extension, you should be aware of what that syntax really means. Otherwise it is a compiler bug allowing that syntax to be accepted.

Regards,

Paul McKenzie