Image Loading Troubles

I have some code to load a uncompressed BTF image file (look at my web site for specs) and my loader keeps crashing. I ran a debug and it crashes where I call the last fread(). I think I'm reading too far into the file, but I can't see how that's possible. I tried adding an extra byte to the end of the file, but it still crashed.

Code:

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// Macro to find the size of the data block.
#define DATABLOCK_SIZE                (width*height*bytedepth)

unsigned char BTFImage::Load(char FileName[FILENAME_MAX], int )
{
        FILE *FileHandle = fopen(FileName, "rb");        // Load the file
        if (!FileHandle)        // If it can't load the file, it more than likely doesn't exist
                return BTF_NOTEXIST;

        unsigned char header[BTF_HEADERSIZE];        // Buffer to hold the header in
        fread(header, BTF_HEADERSIZE, 1, FileHandle); // Read the header
       
        if (header[0] != 0x42 || header[1] != 0x54 || header[2] != 0x46) // Check the key
                return BTF_BADFILE;

        switch (header[3])        // Decode the flag byte
        {
        case 0x10:
                compression = BTF_CLEAN;
                bytedepth = 1;
                break;
        case 0x12:
                compression = BTF_RLELOOKUP;
                bytedepth = 1;
                break;
        case 0x13:
                compression = BTF_RLELOOKUPINV;
                bytedepth = 1;
                break;
        case 0x30:
                compression = BTF_CLEAN;
                bytedepth = 3;
                break;
        case 0x31:
                compression = BTF_LOOKUP;
                bytedepth = 3;
                break;
        case 0x32:
                compression = BTF_RLELOOKUP;
                bytedepth = 3;
                break;
        case 0x33:
                compression = BTF_RLELOOKUPINV;
                bytedepth = 3;
                break;
        case 0x40:
                compression = BTF_CLEAN;
                bytedepth = 4;
                break;
        case 0x41:
                compression = BTF_LOOKUP;
                bytedepth = 4;
                break;
        case 0x42:
                compression = BTF_RLELOOKUP;
                bytedepth = 4;
                break;
        case 0x43:
                compression = BTF_RLELOOKUPINV;
                bytedepth = 4;
                break;
        default:
                return BTF_BADFLAGBYTE;
        }

        width = header[4] * 256 + header[5];        // Find width and height
        height = header[6] * 256 + header[7];

        data = new unsigned char[DATABLOCK_SIZE];        // Allocate space for the image data
        if (data = 0)        // If the file is GIGANTIC and you are out of RAM, return BTF_NORAM
                return BTF_NORAM;

        if (compression == BTF_CLEAN)        // If no compression
                fread(data, DATABLOCK_SIZE, 1, FileHandle);        // Read the whole block directly

        footer = 0;
        fclose(FileHandle);        // Close the file
//        filename = FileName;        // Set the filename to the one passed to us
}

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Here is the file I'm loading (in hexadecimal format)

Code:

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42 54 46 10 00 01 00 01 05

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> if (data = 0)
Oops, you just lost your memory
Try
if (data == 0)

OMG, I'm such an idiot. That's a major n00b mistake.

I guess everyone does something like this every once in a while. Even John Carmack probably does little things like this once in a while.

Most modern compilers will warn you about such assignments where a comparison was intended.

I'd suggest testing your compiler to see what you get.