filebuf_virtuals.cc

gcc3.2.1源代码

// 2001-05-21 Benjamin Kosnik  <[e-mail]>

// Copyright (C) 2001, 2002 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING.  If not, write to the Free
// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// USA.

// 27.8.1.4 Overridden virtual functions

#include <fstream>
#include <testsuite_hooks.h>

// @require@ %-*.tst %-*.txt
// @diff@ %-*.tst %*.txt

void test01()
{
  using namespace std;

  bool test = true;
  char buf[512];
  const char* strlit = "how to tell a story and other essays: mark twain";
  const size_t strlitsize = std::strlen(strlit);
  filebuf fbuf01;

  fbuf01.pubsetbuf(buf, 512);
  fbuf01.sputn(strlit, strlitsize);
  VERIFY( std::strncmp(strlit, buf, strlitsize) != 0 );
}

void test02()
{
  using namespace std;

  bool test = true;
  char buf[512];
  const char* strlit = "how to tell a story and other essays: mark twain";
  const size_t strlitsize = std::strlen(strlit);
  filebuf fbuf01;
  fbuf01.open("tmp", ios_base::out);

  fbuf01.pubsetbuf(buf, strlitsize);
  fbuf01.sputn(strlit, strlitsize);
  VERIFY( std::strncmp(strlit, buf, strlitsize) == 0 );
}


// NB: This test assumes that _M_buf_size == 40, and not the usual
// buffer_size length of BUFSIZ (8192), so that overflow/underflow can be
// simulated a bit more readily.
// NRB (Nota Really Bene): setting it to 40 breaks the test, as intended.
const int buffer_size = 8192;
//const int buffer_size = 40;

const char carray_01[] = "santa cruz or sandiego?";
const char carray_02[] = "memphis, new orleans, and savanah";
const char name_01[] = "filebuf_virtuals-1.txt"; // file with data in it
const char name_02[] = "filebuf_virtuals-2.txt"; // empty file, need to create
const char name_03[] = "filebuf_virtuals-3.txt"; // empty file, need to create


class derived_filebuf: public std::filebuf
{
 public:
  void
  set_size(int_type __size) { _M_buf_size_opt = __size; }
};

derived_filebuf fb_01; // in 
derived_filebuf fb_02; // out
derived_filebuf fb_03; // in | out


// Initialize filebufs to be the same size regardless of platform.
void test03()
{
  fb_01.set_size(buffer_size);
  fb_02.set_size(buffer_size);
  fb_03.set_size(buffer_size);
}


// Test the filebuf/stringbuf locale settings.
void test04() 
{
  std::locale loc_tmp;
  loc_tmp = fb_01.getloc();
  fb_01.pubimbue(loc_tmp); //This should initialize _M_init to true
  fb_01.getloc(); //This should just return _M_locale
}

// Test overloaded virtual functions.
void test05() 
{
  typedef std::filebuf::int_type 	int_type;
  typedef std::filebuf::traits_type 	traits_type;
  typedef std::filebuf::pos_type 	pos_type;
  typedef std::filebuf::off_type 	off_type;
  typedef size_t 			size_type;

  bool 					test = true;
  std::filebuf 				f_tmp;
  std::streamsize 			strmsz_1, strmsz_2;
  std::streamoff  			strmof_1, strmof_2;
  int 					i = 0, j = 0, k = 0;

  // GET
  // int showmanyc()
  // returns an estimate of the numbers of chars in the seq, or -1.
  // if __retval > 0, then calls to underflow won't return
  // traits_type::eof() till at least __retval chars. 
  // if __retval == -1, then calls to underflow or uflow will fail.
  // NB overriding def if it can determine more chars can be read from 
  // the input sequence.

  // int in_avail()
  // if a read position is available, return _M_in_end - _M_in_cur.
  // else return showmanyc.
  strmof_1 = fb_01.in_avail();
  strmof_2 = fb_02.in_avail();
  VERIFY( strmof_1 == -1 );
  VERIFY( strmof_1 == strmof_2 ); //fail because not open
  strmof_1 = fb_03.in_avail();
  VERIFY( strmof_1 == strmof_2 );
  fb_01.open(name_01, std::ios_base::in);
  fb_02.open(name_02, std::ios_base::out | std::ios_base::trunc);
  fb_03.open(name_03, std::ios_base::out | std::ios_base::in | std::ios_base::trunc); 
  strmof_1 = fb_01.in_avail();
  strmof_2 = fb_02.in_avail();
  VERIFY( strmof_1 != strmof_2 );
  VERIFY( strmof_1 >= 0 );
  VERIFY( strmof_2 == -1 );  // empty file
  strmof_1 = fb_03.in_avail(); 
  VERIFY( strmof_1  == 0 ); // empty file

  // int_type sbumpc()
  // if read_cur not avail returns uflow(), else return *read_cur & increment
  int_type c1 = fb_01.sbumpc();
  int_type c2 = fb_02.sbumpc();
  VERIFY( c1 != c2 );
  VERIFY( c1 == '/' );
  VERIFY( c2 == -1 );
  int_type c3 = fb_01.sbumpc();
  int_type c4 = fb_02.sbumpc();
  VERIFY( c3 != c4 );
  VERIFY( c1 == c3 ); // fluke, both happen to be '/'
  VERIFY( c2 == c4 );
  int_type c5 = fb_03.sbumpc();
  VERIFY( c5 == traits_type::eof() );
  // XXX should do some kind of test to make sure that internal
  // buffers point ot the same thing, to check consistancy.

  // int_type sgetc()
  // if read_cur not avail, return uflow(), else return *read_cur  
  int_type c6 = fb_01.sgetc();
  int_type c7 = fb_02.sgetc();
  VERIFY( c6 != c3 );
  VERIFY( c7 == c4 ); // both -1
  int_type c8 = fb_01.sgetc();
  int_type c9 = fb_02.sgetc();
  VERIFY( c6 == c8 );
  VERIFY( c7 == c9 );
  c5 = fb_03.sgetc();
  VERIFY( c5 == traits_type::eof() );

  // int_type snextc()
  // calls sbumpc and if sbumpc != eof, return sgetc
  c6 = fb_01.snextc();
  c7 = fb_02.snextc();
  VERIFY( c6 != c8 );
  VERIFY( c7 == c9 ); // -1
  VERIFY( c6 == '9' );
  c6 = fb_01.snextc();
  c7 = fb_02.snextc();
  VERIFY( c6 != c8 );
  VERIFY( c7 == c9 ); // -1
  VERIFY( c6 == '9' );
  c5 = fb_03.snextc();
  VERIFY( c5 == traits_type::eof() );

  // streamsize sgetn(char_type *s, streamsize n)
  // streamsize xsgetn(char_type *s, streamsize n)
  // assign up to n chars to s from input sequence, indexing in_cur as
  // approp and returning the number of chars assigned
  strmsz_1 = fb_01.in_avail();
  strmsz_2 = fb_02.in_avail();
  test = strmsz_1 != strmsz_2;
  char carray1[13] = "";
  strmsz_1 = fb_01.sgetn(carray1, 10);
  char carray2[buffer_size] = "";
  strmsz_2 = fb_02.sgetn(carray2, 10);
  VERIFY( strmsz_1 != strmsz_2 );
  VERIFY( strmsz_1 == 10 );
  VERIFY( strmsz_2 == 0 );
  c1 = fb_01.sgetc();
  c2 = fb_02.sgetc();
  VERIFY( c1 == '\n' );  
  VERIFY( c7 == c2 ); // n != i
  strmsz_1 = fb_03.sgetn(carray1, 10);
  VERIFY( !strmsz_1 ); //zero
  strmsz_1 = fb_01.in_avail();
  strmsz_2 = fb_01.sgetn(carray2, strmsz_1 + 5);
  VERIFY( strmsz_1 == strmsz_2 - 5 ); 
  c4 = fb_01.sgetc(); // buffer should have underflowed from above.
  VERIFY( c4 == 'i' );
  strmsz_1 = fb_01.in_avail();
  VERIFY( strmsz_1 > 0 );
  strmsz_2 = fb_01.sgetn(carray2, strmsz_1 + 5);
  VERIFY( strmsz_1 == strmsz_2 ); //at the end of the actual file 
  strmsz_1 = fb_02.in_avail();
  strmsz_2 = fb_02.sgetn(carray2, strmsz_1 + 5);
  VERIFY( strmsz_1 == -1 );
  VERIFY( strmsz_2 == 0 );
  c4 = fb_02.sgetc(); // should be EOF
  VERIFY( c4 == traits_type::eof() );

  // PUT
  // int_type sputc(char_type c)
  // if out_cur not avail, return overflow(traits_type::to_int_type(c)) 
  // else, stores c at out_cur,
  // increments out_cur, and returns c as int_type
  // strmsz_1 = fb_03.in_avail();  // XXX valid for in|out??
  c1 = fb_02.sputc('a'); 
  c2 = fb_03.sputc('b'); 
  VERIFY( c1 != c2 );
  c1 = fb_02.sputc('c'); 
  c2 = fb_03.sputc('d'); 
  VERIFY( c1 != c2 );
  // strmsz_2 = fb_03.in_avail();
  // VERIFY( strmsz_1 != strmsz_2 );
  for (int i = 50; i <= 90; ++i) 
    c2 = fb_02.sputc(char(i));
  // 27filebuf-2.txt == ac23456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWX
  // fb_02._M_out_cur = '2'
  strmsz_1 = fb_03.in_avail();
  for (int i = 50; i <= 90; ++i) 
    c2 = fb_03.sputc(char(i));
  strmsz_2 = fb_03.in_avail();
  // VERIFY( strmsz_1 != strmsz_2 );
  // VERIFY( strmsz_1 > 0 );
  // VERIFY( strmsz_2 > 0 );
  // 27filebuf-2.txt == bd23456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWX
  // fb_02._M_out_cur = '2'
  c3 = fb_01.sputc('a'); // should be EOF because this is read-only
  VERIFY( c3 == traits_type::eof() );

  // streamsize sputn(const char_typs* s, streamsize n)
  // write up to n chars to out_cur from s, returning number assigned
  // NB *sputn will happily put '\0' into your stream if you give it a chance*
  strmsz_1 = fb_03.sputn("racadabras", 10);//"abracadabras or what?"
  VERIFY( strmsz_1 == 10 );
  strmsz_2 = fb_03.sputn(", i wanna reach out and", 10);