| // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com) |
| // (C) Copyright 2003-2007 Jonathan Turkanis |
| // Distributed under the Boost Software License, Version 1.0. (See accompanying |
| // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.) |
| |
| // See http://www.boost.org/libs/iostreams for documentation. |
| |
| // Contains the definitions of the class templates symmetric_filter, |
| // which models DualUseFilter based on a model of the Symmetric Filter. |
| |
| // |
| // Roughly, a Symmetric Filter is a class type with the following interface: |
| // |
| // struct symmetric_filter { |
| // typedef xxx char_type; |
| // |
| // bool filter( const char*& begin_in, const char* end_in, |
| // char*& begin_out, char* end_out, bool flush ) |
| // { |
| // // Consume as many characters as possible from the interval |
| // // [begin_in, end_in), without exhausting the output range |
| // // [begin_out, end_out). If flush is true, write as mush output |
| // // as possible. |
| // // A return value of true indicates that filter should be called |
| // // again. More precisely, if flush is false, a return value of |
| // // false indicates that the natural end of stream has been reached |
| // // and that all filtered data has been forwarded; if flush is |
| // // true, a return value of false indicates that all filtered data |
| // // has been forwarded. |
| // } |
| // void close() { /* Reset filter's state. */ } |
| // }; |
| // |
| // Symmetric Filter filters need not be CopyConstructable. |
| // |
| |
| #ifndef NDNBOOST_IOSTREAMS_SYMMETRIC_FILTER_HPP_INCLUDED |
| #define NDNBOOST_IOSTREAMS_SYMMETRIC_FILTER_HPP_INCLUDED |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1020) |
| # pragma once |
| #endif |
| |
| #include <ndnboost/assert.hpp> |
| #include <memory> // allocator, auto_ptr. |
| #include <ndnboost/config.hpp> // NDNBOOST_DEDUCED_TYPENAME. |
| #include <ndnboost/iostreams/char_traits.hpp> |
| #include <ndnboost/iostreams/constants.hpp> // buffer size. |
| #include <ndnboost/iostreams/detail/buffer.hpp> |
| #include <ndnboost/iostreams/detail/char_traits.hpp> |
| #include <ndnboost/iostreams/detail/config/limits.hpp> |
| #include <ndnboost/iostreams/detail/template_params.hpp> |
| #include <ndnboost/iostreams/traits.hpp> |
| #include <ndnboost/iostreams/operations.hpp> // read, write. |
| #include <ndnboost/iostreams/pipeline.hpp> |
| #include <ndnboost/preprocessor/iteration/local.hpp> |
| #include <ndnboost/preprocessor/punctuation/comma_if.hpp> |
| #include <ndnboost/preprocessor/repetition/enum_binary_params.hpp> |
| #include <ndnboost/preprocessor/repetition/enum_params.hpp> |
| #include <ndnboost/shared_ptr.hpp> |
| |
| // Must come last. |
| #include <ndnboost/iostreams/detail/config/disable_warnings.hpp> // MSVC. |
| |
| namespace ndnboost { namespace iostreams { |
| |
| template< typename SymmetricFilter, |
| typename Alloc = |
| std::allocator< |
| NDNBOOST_DEDUCED_TYPENAME char_type_of<SymmetricFilter>::type |
| > > |
| class symmetric_filter { |
| public: |
| typedef typename char_type_of<SymmetricFilter>::type char_type; |
| typedef NDNBOOST_IOSTREAMS_CHAR_TRAITS(char_type) traits_type; |
| typedef std::basic_string<char_type, traits_type, Alloc> string_type; |
| struct category |
| : dual_use, |
| filter_tag, |
| multichar_tag, |
| closable_tag |
| { }; |
| |
| // Expands to a sequence of ctors which forward to impl. |
| #define NDNBOOST_PP_LOCAL_MACRO(n) \ |
| NDNBOOST_IOSTREAMS_TEMPLATE_PARAMS(n, T) \ |
| explicit symmetric_filter( \ |
| int buffer_size NDNBOOST_PP_COMMA_IF(n) \ |
| NDNBOOST_PP_ENUM_BINARY_PARAMS(n, const T, &t) ) \ |
| : pimpl_(new impl(buffer_size NDNBOOST_PP_COMMA_IF(n) \ |
| NDNBOOST_PP_ENUM_PARAMS(n, t))) \ |
| { NDNBOOST_ASSERT(buffer_size > 0); } \ |
| /**/ |
| #define NDNBOOST_PP_LOCAL_LIMITS (0, NDNBOOST_IOSTREAMS_MAX_FORWARDING_ARITY) |
| #include NDNBOOST_PP_LOCAL_ITERATE() |
| #undef NDNBOOST_PP_LOCAL_MACRO |
| |
| template<typename Source> |
| std::streamsize read(Source& src, char_type* s, std::streamsize n) |
| { |
| using namespace std; |
| if (!(state() & f_read)) |
| begin_read(); |
| |
| buffer_type& buf = pimpl_->buf_; |
| int status = (state() & f_eof) != 0 ? f_eof : f_good; |
| char_type *next_s = s, |
| *end_s = s + n; |
| while (true) |
| { |
| // Invoke filter if there are unconsumed characters in buffer or if |
| // filter must be flushed. |
| bool flush = status == f_eof; |
| if (buf.ptr() != buf.eptr() || flush) { |
| const char_type* next = buf.ptr(); |
| bool done = |
| !filter().filter(next, buf.eptr(), next_s, end_s, flush); |
| buf.ptr() = buf.data() + (next - buf.data()); |
| if (done) |
| return detail::check_eof( |
| static_cast<std::streamsize>(next_s - s) |
| ); |
| } |
| |
| // If no more characters are available without blocking, or |
| // if read request has been satisfied, return. |
| if ( (status == f_would_block && buf.ptr() == buf.eptr()) || |
| next_s == end_s ) |
| { |
| return static_cast<std::streamsize>(next_s - s); |
| } |
| |
| // Fill buffer. |
| if (status == f_good) |
| status = fill(src); |
| } |
| } |
| |
| template<typename Sink> |
| std::streamsize write(Sink& snk, const char_type* s, std::streamsize n) |
| { |
| if (!(state() & f_write)) |
| begin_write(); |
| |
| buffer_type& buf = pimpl_->buf_; |
| const char_type *next_s, *end_s; |
| for (next_s = s, end_s = s + n; next_s != end_s; ) { |
| if (buf.ptr() == buf.eptr() && !flush(snk)) |
| break; |
| if(!filter().filter(next_s, end_s, buf.ptr(), buf.eptr(), false)) { |
| flush(snk); |
| break; |
| } |
| } |
| return static_cast<std::streamsize>(next_s - s); |
| } |
| |
| template<typename Sink> |
| void close(Sink& snk, NDNBOOST_IOS::openmode mode) |
| { |
| if (mode == NDNBOOST_IOS::out) { |
| |
| if (!(state() & f_write)) |
| begin_write(); |
| |
| // Repeatedly invoke filter() with no input. |
| try { |
| buffer_type& buf = pimpl_->buf_; |
| char_type dummy; |
| const char_type* end = &dummy; |
| bool again = true; |
| while (again) { |
| if (buf.ptr() != buf.eptr()) |
| again = filter().filter( end, end, buf.ptr(), |
| buf.eptr(), true ); |
| flush(snk); |
| } |
| } catch (...) { |
| try { close_impl(); } catch (...) { } |
| throw; |
| } |
| close_impl(); |
| } else { |
| close_impl(); |
| } |
| } |
| SymmetricFilter& filter() { return *pimpl_; } |
| string_type unconsumed_input() const; |
| |
| // Give impl access to buffer_type on Tru64 |
| #if !NDNBOOST_WORKAROUND(__DECCXX_VER, NDNBOOST_TESTED_AT(60590042)) |
| private: |
| #endif |
| typedef detail::buffer<char_type, Alloc> buffer_type; |
| private: |
| buffer_type& buf() { return pimpl_->buf_; } |
| const buffer_type& buf() const { return pimpl_->buf_; } |
| int& state() { return pimpl_->state_; } |
| void begin_read(); |
| void begin_write(); |
| |
| template<typename Source> |
| int fill(Source& src) |
| { |
| std::streamsize amt = iostreams::read(src, buf().data(), buf().size()); |
| if (amt == -1) { |
| state() |= f_eof; |
| return f_eof; |
| } |
| buf().set(0, amt); |
| return amt != 0 ? f_good : f_would_block; |
| } |
| |
| // Attempts to write the contents of the buffer the given Sink. |
| // Returns true if at least on character was written. |
| template<typename Sink> |
| bool flush(Sink& snk) |
| { |
| typedef typename iostreams::category_of<Sink>::type category; |
| typedef is_convertible<category, output> can_write; |
| return flush(snk, can_write()); |
| } |
| |
| template<typename Sink> |
| bool flush(Sink& snk, mpl::true_) |
| { |
| std::streamsize amt = |
| static_cast<std::streamsize>(buf().ptr() - buf().data()); |
| std::streamsize result = |
| ndnboost::iostreams::write(snk, buf().data(), amt); |
| if (result < amt && result > 0) |
| traits_type::move(buf().data(), buf().data() + result, amt - result); |
| buf().set(amt - result, buf().size()); |
| return result != 0; |
| } |
| |
| template<typename Sink> |
| bool flush(Sink&, mpl::false_) { return true;} |
| |
| void close_impl(); |
| |
| enum flag_type { |
| f_read = 1, |
| f_write = f_read << 1, |
| f_eof = f_write << 1, |
| f_good, |
| f_would_block |
| }; |
| |
| struct impl : SymmetricFilter { |
| |
| // Expands to a sequence of ctors which forward to SymmetricFilter. |
| #define NDNBOOST_PP_LOCAL_MACRO(n) \ |
| NDNBOOST_IOSTREAMS_TEMPLATE_PARAMS(n, T) \ |
| impl( int buffer_size NDNBOOST_PP_COMMA_IF(n) \ |
| NDNBOOST_PP_ENUM_BINARY_PARAMS(n, const T, &t) ) \ |
| : SymmetricFilter(NDNBOOST_PP_ENUM_PARAMS(n, t)), \ |
| buf_(buffer_size), state_(0) \ |
| { } \ |
| /**/ |
| #define NDNBOOST_PP_LOCAL_LIMITS (0, NDNBOOST_IOSTREAMS_MAX_FORWARDING_ARITY) |
| #include NDNBOOST_PP_LOCAL_ITERATE() |
| #undef NDNBOOST_PP_LOCAL_MACRO |
| |
| buffer_type buf_; |
| int state_; |
| }; |
| |
| shared_ptr<impl> pimpl_; |
| }; |
| NDNBOOST_IOSTREAMS_PIPABLE(symmetric_filter, 2) |
| |
| //------------------Implementation of symmetric_filter----------------// |
| |
| template<typename SymmetricFilter, typename Alloc> |
| void symmetric_filter<SymmetricFilter, Alloc>::begin_read() |
| { |
| NDNBOOST_ASSERT(!(state() & f_write)); |
| state() |= f_read; |
| buf().set(0, 0); |
| } |
| |
| template<typename SymmetricFilter, typename Alloc> |
| void symmetric_filter<SymmetricFilter, Alloc>::begin_write() |
| { |
| NDNBOOST_ASSERT(!(state() & f_read)); |
| state() |= f_write; |
| buf().set(0, buf().size()); |
| } |
| |
| template<typename SymmetricFilter, typename Alloc> |
| void symmetric_filter<SymmetricFilter, Alloc>::close_impl() |
| { |
| state() = 0; |
| buf().set(0, 0); |
| filter().close(); |
| } |
| |
| template<typename SymmetricFilter, typename Alloc> |
| typename symmetric_filter<SymmetricFilter, Alloc>::string_type |
| symmetric_filter<SymmetricFilter, Alloc>::unconsumed_input() const |
| { return string_type(buf().ptr(), buf().eptr()); } |
| |
| //----------------------------------------------------------------------------// |
| |
| } } // End namespaces iostreams, boost. |
| |
| #include <ndnboost/iostreams/detail/config/enable_warnings.hpp> // MSVC. |
| |
| #endif // #ifndef NDNBOOST_IOSTREAMS_SYMMETRIC_FILTER_HPP_INCLUDED |