mudhorn/zxing
1
0
Fork 0
mirror of https://github.com/zxing/zxing.git synced 2024-09-20 05:27:32 -07:00
Code Issues Actions Packages Projects Releases Wiki Activity

Avoid possible AIOOBE on bad input

Browse source 
git-svn-id: https://zxing.googlecode.com/svn/trunk@1437 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
srowen 2010-06-16 21:12:43 +00:00
parent 8cbe558ec3
commit 627cd6cab0
1 changed files with 17 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

27
core/src/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java
View file

@ -168,21 +168,28 @@ final class DecodedBitStreamParser {
byteSegments.addElement(readBytes);
}
private static char toAlphaNumericChar(int value) throws FormatException {
if (value >= ALPHANUMERIC_CHARS.length) {
throw FormatException.getFormatInstance();
}
return ALPHANUMERIC_CHARS[value];
}
private static void decodeAlphanumericSegment(BitSource bits,
StringBuffer result,
int count,
boolean fc1InEffect) {
boolean fc1InEffect) throws FormatException {
// Read two characters at a time
int start = result.length();
while (count > 1) {
int nextTwoCharsBits = bits.readBits(11);
result.append(ALPHANUMERIC_CHARS[nextTwoCharsBits / 45]);
result.append(ALPHANUMERIC_CHARS[nextTwoCharsBits % 45]);
result.append(toAlphaNumericChar(nextTwoCharsBits / 45));
result.append(toAlphaNumericChar(nextTwoCharsBits % 45));
count -= 2;
}
if (count == 1) {
// special case: one character left
result.append(ALPHANUMERIC_CHARS[bits.readBits(6)]);
result.append(toAlphaNumericChar(bits.readBits(6)));
}
// See section 6.4.8.1, 6.4.8.2
if (fc1InEffect) {
@ -211,9 +218,9 @@ final class DecodedBitStreamParser {
if (threeDigitsBits >= 1000) {
throw FormatException.getFormatInstance();
}
result.append(ALPHANUMERIC_CHARS[threeDigitsBits / 100]);
result.append(ALPHANUMERIC_CHARS[(threeDigitsBits / 10) % 10]);
result.append(ALPHANUMERIC_CHARS[threeDigitsBits % 10]);
result.append(toAlphaNumericChar(threeDigitsBits / 100));
result.append(toAlphaNumericChar((threeDigitsBits / 10) % 10));
result.append(toAlphaNumericChar(threeDigitsBits % 10));
count -= 3;
}
if (count == 2) {
@ -222,15 +229,15 @@ final class DecodedBitStreamParser {
if (twoDigitsBits >= 100) {
throw FormatException.getFormatInstance();
}
result.append(ALPHANUMERIC_CHARS[twoDigitsBits / 10]);
result.append(ALPHANUMERIC_CHARS[twoDigitsBits % 10]);
result.append(toAlphaNumericChar(twoDigitsBits / 10));
result.append(toAlphaNumericChar(twoDigitsBits % 10));
} else if (count == 1) {
// One digit left over to read
int digitBits = bits.readBits(4);
if (digitBits >= 10) {
throw FormatException.getFormatInstance();
}
result.append(ALPHANUMERIC_CHARS[digitBits]);
result.append(toAlphaNumericChar(digitBits));
}
}