Plamen Totev created COMPRESS-395:
-------------------------------------
Summary: Zip - Do not add data descriptor record when CRC and size
value are known
Key: COMPRESS-395
URL: https://issues.apache.org/jira/browse/COMPRESS-395
Project: Commons Compress
Issue Type: Improvement
Reporter: Plamen Totev
Priority: Minor
Hi,
Currently {{ZipArchiveOutputStream}} will add data descriptor record when the
output do not provide random access. But if you add an entry using
{{addRawArchiveEntry}} then the CRC, compressed size and uncompressed size
could be know and there is no need for data descriptor record as those values
could be set in the local file header. The current implementation does both -
it sets the correct value in the local file header and adds additional data
descriptor record. Here is the relevant code from
{{ZipArchiveOutputStream#putArchiveEntry}}:
{code:java}
// just a placeholder, real data will be in data
// descriptor or inserted later via SeekableByteChannel
ZipEightByteInteger size = ZipEightByteInteger.ZERO;
ZipEightByteInteger compressedSize = ZipEightByteInteger.ZERO;
if (phased){
size = new ZipEightByteInteger(entry.entry.getSize());
compressedSize = new
ZipEightByteInteger(entry.entry.getCompressedSize());
} else if (entry.entry.getMethod() == STORED
&& entry.entry.getSize() != ArchiveEntry.SIZE_UNKNOWN) {
// actually, we already know the sizes
size = new ZipEightByteInteger(entry.entry.getSize());
compressedSize = size;
}
z64.setSize(size);
z64.setCompressedSize(compressedSize);
{code}
Maybe {{ZipArchiveOutputStream}} could be improved to not add data descriptor
record when the CRC and size values are known in advance.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
