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#ifndef _PYFSTREAM_H
#define _PYFSTREAM_H
#include <istream>
#include <ostream>
#include <streambuf>
#include <cstdio>
#include <cstring>
#include "Python.h"
// pyofstream
// - a stream that writes on a Python file object
class pyoutbuf : public std::streambuf {
protected:
PyFileObject * fo; // Python file object
public:
// constructor
pyoutbuf (PyFileObject * _fo) : fo(_fo) {}
protected:
// write one character
virtual int_type overflow (int_type c) {
if (c != EOF) {
char z[2];
z[0] = c;
z[1] = '\0';
if (PyFile_WriteString(z, (PyObject *)fo) < 0) {
return EOF;
}
}
return c;
}
// write multiple characters
virtual std::streamsize xsputn (const char* s, std::streamsize num) {
if (PyFile_WriteString(s, (PyObject *)fo) < 0)
return 0;
return num;
}
};
class pyofstream : public std::ostream {
protected:
pyoutbuf buf;
public:
pyofstream (PyFileObject * fo) : std::ostream(0), buf(fo) {
rdbuf(&buf);
}
};
// pyifstream
// - a stream that reads on a file descriptor
class pyinbuf : public std::streambuf {
protected:
PyFileObject * fo; // Python file object
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()
*/
pyinbuf (PyFileObject * _fo) : fo(_fo) {
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;
PyObject *line = PyFile_GetLine((PyObject *)fo, bufSize);
if (! line || ! PyString_Check(line)) {
// ERROR or EOF
return EOF;
}
num = PyString_Size(line);
if (num == 0)
return EOF;
memmove (buffer+pbSize, PyString_AsString(line), num);
// 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 pyifstream : public std::istream {
protected:
pyinbuf buf;
public:
pyifstream (PyFileObject * fo) : std::istream(0), buf(fo) {
rdbuf(&buf);
}
};
#endif // _PYFSTREAM_H
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