Tweaked Java code to prevent arithmetic overflow for huge input data.

java/io/nayuki/qrcodegen/BitBuffer.java

@@ -82,7 +82,7 @@ public final class BitBuffer implements Cloneable {
 	 * @return this sequence as a new array of bytes (not {@code null})
 	 */
 	public byte[] getBytes() {
-		byte[] result = new byte[(bitLength + 7) / 8];
+		byte[] result = new byte[(bitLength + 7) >>> 3];  // Round up to whole byte, won't overflow
 		for (int i = 0; i < bitLength; i++)
 			result[i >>> 3] |= data.get(i) ? 1 << (7 - (i & 7)) : 0;
 		return result;

java/io/nayuki/qrcodegen/QrSegment.java

@@ -71,7 +71,7 @@ public final class QrSegment {
 		
 		BitBuffer bb = new BitBuffer();
 		int i;
-		for (i = 0; i + 3 <= digits.length(); i += 3)  // Process groups of 3
+		for (i = 0; i <= digits.length() - 3; i += 3)  // Process groups of 3
 			bb.appendBits(Integer.parseInt(digits.substring(i, i + 3)), 10);
 		int rem = digits.length() - i;
 		if (rem > 0)  // 1 or 2 digits remaining
@@ -96,7 +96,7 @@ public final class QrSegment {
 		
 		BitBuffer bb = new BitBuffer();
 		int i;
-		for (i = 0; i + 2 <= text.length(); i += 2) {  // Process groups of 2
+		for (i = 0; i <= text.length() - 2; i += 2) {  // Process groups of 2
 			int temp = ALPHANUMERIC_CHARSET.indexOf(text.charAt(i)) * 45;
 			temp += ALPHANUMERIC_CHARSET.indexOf(text.charAt(i + 1));
 			bb.appendBits(temp, 11);