[iostreams] : bug in <boost/iostreams/copy.hpp> ?
Hello, i'm a new user to these great boost libraries... I think i found a bug in <boost/iostreams/copy.hpp> (version 1.33.1) the current code starting line 80 is template<typename Source, typename Sink> std::streamsize copy_impl( Source& src, Sink& snk, std::streamsize buffer_size, mpl::false_, mpl::true_ ) { // Copy from an indirect Source to a direct Sink. using namespace std; typedef typename char_type_of<Source>::type char_type; typedef pair<char_type*, char_type*> pair_type; detail::basic_buffer<char_type> buf(buffer_size); pair_type p = snk.output_sequence(); streamsize total = 0; bool done = false; while (!done) { streamsize amt; done = (amt = iostreams::read(src, buf.data(), buffer_size)) == -1; std::copy(buf.data(), buf.data() + amt, p.first + total); if (amt != -1) total += amt; } return total; } I think it should be somthing like template<typename Source, typename Sink> std::streamsize copy_impl( Source& src, Sink& snk, std::streamsize buffer_size, mpl::false_, mpl::true_ ) { // Copy from an indirect Source to a direct Sink. using namespace std; typedef typename char_type_of<Source>::type char_type; typedef pair<char_type*, char_type*> pair_type; detail::basic_buffer<char_type> buf(buffer_size); pair_type p = snk.output_sequence(); streamsize total = 0; streamsize amt = 0; //bool done = false; while ((amt = iostreams::read(src, buf.data(),buffer_size))!= -1) { std::copy(buf.data(), buf.data() + amt, p.first + total); total += amt; } return total; } The current code happens to crash whereas the proposed version works properly... Did I miss something or a I right ? Regards, Mathieu -- http://matioupi.free.fr/
Mathieu Peyréga wrote:
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The current code happens to crash whereas the proposed version works properly... Did I miss something or a I right ?
I am not a boost iostreams expert... just a user. Having said that, if iostreams::read() can return -1 during the copy_impl then it looks like the original code could be a problem. What was your test case to demonstrate this?
and it happens... it is indeed the test used to detect the end of the loop...
What was your test case to demonstrate this?
was something like short *data = new short[w*h]; for(int index_ligne=0;index_ligne<w;++index_ligne) { TIFFReadScanline(handler,data+(index_ligne*w), index_ligne); } ofstream file(filename.c_str(), ios_base::out|ios_base::binary); filtering_streambuf<output> out; out.push(bzip2_compressor()); out.push(file); basic_array_source<char> datastream((char*)data,w*h*sizeof(short)); boost::iostreams::copy(datastream, out); Regards, Mathieu -- http://matioupi.free.fr/
I hope someone who has check-in privileges can look at this and confirm/apply the patch before 1.34 gets released.
I hope too... They could at least let us know what they think about this point... (as far as i'm concerned, the patch is applied on the boost sources i use) I saw that they prefer patch delivered in "patch" format, but i don't know how to do that (especially on a windows environnement...)
Mathieu Peyréga wrote:
I think the following change should work as well AND it mimics the copy_impl() function right below the one you changed... (i.e. the one that does a "Copy from an indirect Source to a indirect Sink...") It just moves the "if" statement up one line. So the while loop now looks like: while (!done) { streamsize amt; done = (amt = iostreams::read(src, buf.data(), buffer_size)) == -1; if (amt != -1) { std::copy(buf.data(), buf.data() + amt, p.first + total); total += amt; } } In any case, I have attached a patch file for this change if you want to pass it on. --- C:\dev\boost_1_33_1\boost\iostreams\copy.hpp Thu May 26 00:37:30 2005 +++ C:\dev\boost_1_33_1\boost\iostreams\Newcopy.hpp Mon Dec 11 17:14:34 2006 @@ -92,9 +92,10 @@ while (!done) { streamsize amt; done = (amt = iostreams::read(src, buf.data(), buffer_size)) == -1; - std::copy(buf.data(), buf.data() + amt, p.first + total); - if (amt != -1) + if (amt != -1) { + std::copy(buf.data(), buf.data() + amt, p.first + total); total += amt; + } } return total; }
eg wrote:
I should read the patch guidelines before posting. The attached patch should conform to the writeup (it applies the same change to "copy.orig" to produce "copy.hpp") --- C:\dev\boost_1_33_1\boost\iostreams\copy.orig Thu May 26 00:37:30 2005 +++ C:\dev\boost_1_33_1\boost\iostreams\copy.hpp Mon Dec 11 17:14:34 2006 @@ -92,9 +92,10 @@ while (!done) { streamsize amt; done = (amt = iostreams::read(src, buf.data(), buffer_size)) == -1; - std::copy(buf.data(), buf.data() + amt, p.first + total); - if (amt != -1) + if (amt != -1) { + std::copy(buf.data(), buf.data() + amt, p.first + total); total += amt; + } } return total; }
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