Here is the patch. I included parameters for both the compression level and the compression strategy, both of them defaulting to the same thing the gzip binary uses.
--Pete
On Wed, Jul 15, 2009 at 4:37 PM, Kenton Varda<ken...@google.com> wrote:
> OK. Make sure that the parameter is optional, with the default matching
> gzip's default. Thanks.
>
> On Wed, Jul 15, 2009 at 4:27 PM, Peter Keen <peter.k...@gmail.com> wrote:
>>
>> It doesn't look like it has an existing interface for setting zlib
>> options. Reading through the source[1], it looks like it chooses
>> Z_BEST_COMPRESSION (-9 to the gzip command line program) whereas gzip
>> defaults to -6. I'll work up a patch to pass the compression value
>> through as another option to the constructor.
>>
>> --Pete
>>
>> On Jul 15, 4:09 pm, Kenton Varda <ken...@google.com> wrote:
>> > Hmm, probably GzipOutputStream is not setting the same compression
>> > parameters as gzip itself uses by default. I'm happy to accept a patch
>> > fixing this. Does the interface (to GzipOutputStream) currently have a
>> > way
>> > to control compression parameters? If not, it probably should.
>> >
>> >
>> >
>> > On Wed, Jul 15, 2009 at 3:50 PM, Peter Keen <peter.k...@gmail.com>
>> > wrote:
>> >
>> > > Hi guys,
>> >
>> > > I'm playing around with protocol buffers for a project at work and I'm
>> > > coming across a possibly weird problem. I have the following setup in
>> > > my main():
>> >
>> > > std::cerr << "creating file" << std::endl;
>> > > int fd = open("blah.repo", O_WRONLY, O_CREAT);
>> > > if ( fd == -1 ) {
>> > > std::cerr << "ERROR: " << errno << " " << strerror(errno) <<
>> > > std::endl;
>> > > return 1;
>> > > }
>> >
>> > > ZeroCopyOutputStream* raw_output = new FileOutputStream(fd);
>> > > GzipOutputStream* gzip_output = new GzipOutputStream(raw_output,
>> > > GzipOutputStream::ZLIB);
>> > > CodedOutputStream* coded_output = new CodedOutputStream
>> > > (gzip_output);
>> > > // CodedOutputStream* coded_output = new CodedOutputStream
>> > > (raw_output);
>> >
>> > > This version takes, say, 8 seconds to create and serialize 100k simple
>> > > messages. If I flip it to not use the GzipOutputStream, it takes
>> > > roughly 1 second. Using gzip(1) to compress the resulting file takes
>> > > less than half a second.
>> >
>> > > Is there an option I need to be setting to bring it up to parity with
>> > > the command-line program or could there be a bug in GzipOutputStream?
>> > > For what it's worth, GzipInputStream is roughly on parity with a raw
>> > > CodedOutputStream.
>> >
>> > > Thanks,
>> > > Pete
>> >>
>
>
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gzip-compression-level.patch
Description: Binary data
