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    <p>This is what you should do:</p> <pre><code>reader.read((char*)myArray, myArrayLength); /* note, that isn't (sizeof myArray) */ if (!reader) { /* report error */ } </code></pre> <p>If there's processing going on inside the loop, then</p> <pre><code>int c = 0; while (c + 2 &lt; myArraySize) //reader is a ifstream open to a BMP file { reader.read(pixelInfo, 3); myArray[c] = (unsigned char)pixelInfo[0]; myArray[c + 1] = (unsigned char)pixelInfo[1]; myArray[c + 2] = (unsigned char)pixelInfo[2]; c += 3; } </code></pre> <p>Trying to read after you've hit the end is not a problem -- you'll get junk in the rest of the array, but you can deal with that at the end.</p> <p>Assuming your array is big enough to hold the whole file invites buffer corruption. Buffer overrun attacks involving image files with carefully crafted incorrect metadata are quite well-known.</p> <ul> <li><a href="http://www.mozilla.org/security/announce/2012/mfsa2012-92.html" rel="nofollow">in Mozilla</a></li> <li><a href="http://www.kb.cert.org/vuls/id/388289" rel="nofollow">in Sun Java</a></li> <li><a href="https://www.kb.cert.org/vuls/id/189754" rel="nofollow">in Internet Explorer</a></li> <li><a href="http://technet.microsoft.com/en-us/security/bulletin/ms06-024" rel="nofollow">in Windows Media Player</a></li> <li><a href="https://bugzilla.mozilla.org/show_bug.cgi?id=251381" rel="nofollow">again in Mozilla</a></li> <li><a href="http://www.securityfocus.com/bid/12506/discuss" rel="nofollow">in MSN Messenger</a></li> <li><a href="http://www.us-cert.gov/cas/techalerts/TA05-362A.html" rel="nofollow">in Windows XP</a></li> </ul> <p><strong>Do not rely on the entire file content fitting in the calculated buffer size.</strong></p>
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    1. COThe code example won't work for me because I wrote a simplified version, I actually change a value here and there during the loop. But the information about the buffer overrun is greatly appreciated, I'm going to work on something to make it safer.
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    2. CO@Danicco: Well then, you can write your loop as `while (c < myArrayLength)`. The important thing is that I/O errors give garbage results, but don't cause crashes. Overrunning the array, on the other hand, is a crash or even worse, a security vulnerability. So I know which condition the loop needs to check for.
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    3. COThis is what I did, it's working perfectly fine now, thanks for the additional info too!
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