[CODEC-130] Base64InputStream.skip skips underlying stream, not output

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.5
• Fix Version/s: 1.7
• Assignee: Unassigned
• Reporter: James Pickering
• Created: 26/Sep/11 11:59
• Updated: 14/Sep/12 20:21
• Resolved: 19/Mar/12 21:00

Description

Base64InputStream.skip() skips within underlying stream, leading to unexpected behaviour.

The following code will reproduce the issue:

@Test
public void testSkip() throws Throwable {
InputStream ins =
new ByteArrayInputStream("AAAA////".getBytes("ISO-8859-1"));//should decode to

{0, 0, 0, 255, 255, 255}

Base64InputStream instance = new Base64InputStream(ins);
assertEquals(3L, instance.skip(3L)); //should skip 3 decoded characters, or 4 encoded characters
assertEquals(255, instance.read()); //Currently returns 3, as it is decoding "A/", not "//"
}

The following code, if added to Base64InputStream, or (BaseNCodecInputStream in the dev build) would resolve the issue:

@Override
public long skip(long n) throws IOException {
//delegate to read()
long bytesRead = 0;
while ((bytesRead < n) && (read() != -1))

{ bytesRead++; }

return bytesRead;
}

More efficient code may be possible.