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Diffstat (limited to 'stp/c_interface/fdstream.h')
-rw-r--r-- | stp/c_interface/fdstream.h | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/stp/c_interface/fdstream.h b/stp/c_interface/fdstream.h new file mode 100644 index 00000000..2cff613c --- /dev/null +++ b/stp/c_interface/fdstream.h @@ -0,0 +1,186 @@ +/*! @brief The following code declares classes to read from and write to + * file descriptore or file handles. + * + * See + * http://www.josuttis.com/cppcode + * for details and the latest version. + * + * - open: + * - integrating BUFSIZ on some systems? + * - optimized reading of multiple characters + * - stream for reading AND writing + * - i18n + * + * (C) Copyright Nicolai M. Josuttis 2001. + * Permission to copy, use, modify, sell and distribute this software + * is granted provided this copyright notice appears in all copies. + * This software is provided "as is" without express or implied + * warranty, and with no claim as to its suitability for any purpose. + * + * Version: Jul 28, 2002 + * History: + * Jul 28, 2002: bugfix memcpy() => memmove() + * fdinbuf::underflow(): cast for return statements + * Aug 05, 2001: first public version + */ +#ifndef BOOST_FDSTREAM_HPP +#define BOOST_FDSTREAM_HPP + +#include <istream> +#include <ostream> +#include <streambuf> + + +// for EOF: +#include <cstdio> +// for memmove(): +#include <cstring> + + +// low-level read and write functions +#ifdef _MSC_VER +# include <io.h> +#else +# include <unistd.h> +//extern "C" { +// int write (int fd, const char* buf, int num); +// int read (int fd, char* buf, int num); +//} +#endif + + +// BEGIN namespace BOOST +namespace std { + + +/************************************************************ + * fdostream + * - a stream that writes on a file descriptor + ************************************************************/ + + +class fdoutbuf : public std::streambuf { + protected: + int fd; // file descriptor + public: + // constructor + fdoutbuf (int _fd) : fd(_fd) { + } + protected: + // write one character + virtual int_type overflow (int_type c) { + if (c != EOF) { + char z = c; + if (write (fd, &z, 1) != 1) { + return EOF; + } + } + return c; + } + // write multiple characters + virtual + std::streamsize xsputn (const char* s, + std::streamsize num) { + return write(fd,s,num); + } +}; + +class fdostream : public std::ostream { + protected: + fdoutbuf buf; + public: + fdostream (int fd) : std::ostream(0), buf(fd) { + rdbuf(&buf); + } +}; + + +/************************************************************ + * fdistream + * - a stream that reads on a file descriptor + ************************************************************/ + +class fdinbuf : public std::streambuf { + protected: + int fd; // file descriptor + protected: + /* data buffer: + * - at most, pbSize characters in putback area plus + * - at most, bufSize characters in ordinary read buffer + */ + static const int pbSize = 4; // size of putback area + static const int bufSize = 1024; // size of the data buffer + char buffer[bufSize+pbSize]; // data buffer + + public: + /* constructor + * - initialize file descriptor + * - initialize empty data buffer + * - no putback area + * => force underflow() + */ + fdinbuf (int _fd) : fd(_fd) { + setg (buffer+pbSize, // beginning of putback area + buffer+pbSize, // read position + buffer+pbSize); // end position + } + + protected: + // insert new characters into the buffer + virtual int_type underflow () { +#ifndef _MSC_VER + using std::memmove; +#endif + + // is read position before end of buffer? + if (gptr() < egptr()) { + return traits_type::to_int_type(*gptr()); + } + + /* process size of putback area + * - use number of characters read + * - but at most size of putback area + */ + int numPutback; + numPutback = gptr() - eback(); + if (numPutback > pbSize) { + numPutback = pbSize; + } + + /* copy up to pbSize characters previously read into + * the putback area + */ + memmove (buffer+(pbSize-numPutback), gptr()-numPutback, + numPutback); + + // read at most bufSize new characters + int num; + num = read (fd, buffer+pbSize, bufSize); + if (num <= 0) { + // ERROR or EOF + return EOF; + } + + // reset buffer pointers + setg (buffer+(pbSize-numPutback), // beginning of putback area + buffer+pbSize, // read position + buffer+pbSize+num); // end of buffer + + // return next character + return traits_type::to_int_type(*gptr()); + } +}; + +class fdistream : public std::istream { + protected: + fdinbuf buf; + public: + fdistream (int fd) : std::istream(0), buf(fd) { + rdbuf(&buf); + } +}; + + +} // END namespace boost + +#endif /*BOOST_FDSTREAM_HPP*/ |