boinc/lib/mfile.h

56 lines
1.9 KiB
C++

// This file is part of BOINC.
// http://boinc.berkeley.edu
// Copyright (C) 2023 University of California
//
// BOINC is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License
// as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// BOINC 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with BOINC. If not, see <http://www.gnu.org/licenses/>.
#ifndef BOINC_MFILE_H
#define BOINC_MFILE_H
#include <cstdio>
#include <cstdarg>
// MFILE provides memory-buffered output with a FILE-type interface.
// BOINC uses this in a couple of places:
// 1) in the GUI RPC system (since in Windows you can't fdopen a socket)
// 2) in the API, to support a primitive form of checkpointing:
// Write all your output (and restart file) to MFILEs.
// The output is buffered in memory.
// Then close or flush all the MFILEs;
// all the buffers will be flushed to disk, almost atomically.
class MFILE {
char* buf; // NULL-terminated
int len;
FILE* f;
public:
MFILE();
~MFILE();
int open(const char* path, const char* mode);
int _putchar(char);
int puts(const char*);
int vprintf(const char* format, va_list);
int printf(const char* format, ...);
size_t write(const void *, size_t size, size_t nitems);
int close();
int flush();
long tell() const;
void get_buf(char*&, int&);
// get the MFILE's internal buffer and its length.
// The caller assumes ownership of the buffer and must free() it.
// The MFILE's buffer is set to empty
};
#endif