Hi Christian
I think you can go with Javas implementation all the way. like this
MessageDigest md = MessageDigest.getInstance("MD5");InputStream is = new FileInputStream("C:\Temp\Small\Movie.mp4"); // Size 700 MB byte [] buffer = new byte [blockSize];int numRead;do { numRead = is.read(buffer); if (numRead > 0) { md.update(buffer, 0, numRead); }} while (numRead != -1); byte[] digest = md.digest();
On Sat Jan 24 2015 at 6:49:18 PM Christian Grün christian.gruen@gmail.com wrote:
Hi Johan,
looks like a useful feature! Currently, we use Java's default implementation for computing hashes [1]. If you want to help us, you could look out for an existing Java md5 hashing source code, which we could then adopt in BaseX!
Best, Christian
[1] https://github.com/BaseXdb/basex/blob/master/basex-core/ src/main/java/org/basex/query/func/hash/HashFn.java
On Sat, Jan 24, 2015 at 11:37 AM, Johan Mörén johan.moren@gmail.com wrote:
Hello!
We have been using the hashing module to calculate md5 checksums on
binary
files successfully for a while. But last week we received our first
really
large file (4.3 gb) and our script threw a
java.lang.OutOfMemoryError: Requested array size exceeds VM limit
We are currently using the 7.8 version of BaseX. I suspect that BaseX materialize the stream returned by file:read-binary as a byte-array when
we
call the hash:md5 function.
This is a snippet of our script where the problem arises ... let $binary := file:read-binary($filePath) let $checksum := lower-case(xs:string(xs:hexBinary(hash:md5($binary)))) ...
I think a nice feature to add to BaseX could either be a new function in
the
file-module called file-checksum($algorithm) that calculates checksum on files in a streaming fashion. Or perhaps an option to the hashing
functions
that indicates that you want them to use streaming.
Regards, Johan Mörén