On 07/31/13 07:16, Larry Evans wrote:
On 07/30/13 13:59, Larry Evans wrote:
On 07/29/13 11:27, Larry Evans wrote:
On 07/29/13 11:10, Larry Evans wrote: [snip]
BTW, I tried modifying Ken's code to use filtering_ostream instead of filtering_streambuf, and it worked. I also removed the ios_base flags and it still worked. Then I tried using stringstream instead of filestream and it no longer worked. Anyone have any clues about why stringstream doesn't work? The code is attached. With the attached code and attached Jamfile.v2, and with:
#define USE_STRINGSTRM
in the code, the KenApplebyStrm.output produced by bjam is in the next attachment. In contrast, with: //#define USE_STRINGSTRM int the code, the KenApplebyStrm.output produced by bjam is in the last attachment. [snip] OOPS. The code attached previously used streambuf instead of stream. The current attachment uses stream.
Based on running the attached both with:
#define USE_FILT_COMPRESS
then with:
//#define USE_FILT_COMPRESS
on line 40 showed that using the gzip_decompressor starts reading at the end of the stream instead of at the beginning.
The corresponding outputs are also attached.
This contrasts with the count filter which starts reading, as one would expect, at the beginning of the stream.
Still trying to track down why.
Changing the:
out.flush()
around line 93 to:
out.strict_sync();
which is described here:
http://www.boost.org/doc/libs/1_54_0/libs/iostreams/doc/classes/filtering_st...
failed to solve problem :( Still trying to track down why.
Maybe the reason is the filter's are not flushable. However, even though the counter filter is also not flushable, the output turns out OK. Finally, I read about reset and pop: http://www.boost.org/doc/libs/1_54_0/libs/iostreams/doc/classes/filtering_st... and both worked to get proper value for actual_out in the attached. The root cause of my difficulties was my assumptions about what out.flush() or out.strict_sync() should have done, and not reading about reset or pop. However, my excuse was that flush and sync are names with pretty much standard meanings; yet, with iostreams, those meanings don't apply completely :(. Hopefully this will help others running into the same problem. -regards, Larry