sintonia/library/ecasound-2.7.2/libecasound/eca-fileio-mmap.cpp

162 lines
4.4 KiB
C++

// ------------------------------------------------------------------------
// eca-fileio-mmap.cpp: mmap based file-I/O and buffering routines.
// Copyright (C) 1999-2002,2009 Kai Vehmanen
//
// This program 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 of the License, or
// (at your option) any later version.
//
// This program 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 program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
// ------------------------------------------------------------------------
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <cstdio>
#include <cstring> /* memcpy */
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#include <sys/stat.h>
#include <sys/types.h>
#include "eca-fileio.h"
#include "eca-fileio-mmap.h"
ECA_FILE_IO_MMAP::ECA_FILE_IO_MMAP(void) { }
ECA_FILE_IO_MMAP::~ECA_FILE_IO_MMAP(void) { }
void ECA_FILE_IO_MMAP::open_file(const std::string& fname,
const std::string& fmode)
{
#ifdef HAVE_MMAP
int openflags = O_RDWR;
int mmapflags = PROT_READ | PROT_WRITE;
fname_rep = fname;
if (fmode == "rb") {
openflags = O_RDONLY;
mmapflags = PROT_READ;
}
else if (fmode == "wb") {
openflags = O_WRONLY;
mmapflags = PROT_WRITE;
}
fd_rep = ::open(fname.c_str(), openflags);
if (!fd_rep) {
file_ready_rep = false;
mode_rep = "";
}
else {
file_ready_rep = true;
file_ended_rep = false;
mode_rep = fmode;
fposition_rep = 0;
flength_rep = get_file_length();
// cerr << fname_rep << ": mmaping region from 0 to " <<
// flength_rep << "." << endl;
buffer_repp = (caddr_t)::mmap(0,
flength_rep,
mmapflags,
MAP_SHARED,
fd_rep,
0);
if (buffer_repp == MAP_FAILED) {
file_ready_rep = false;
mode_rep = "";
}
}
#else /* HAVE_MMAP */
file_ready_rep = false;
mode_rep = "";
#endif
}
void ECA_FILE_IO_MMAP::close_file(void) {
// cerr << fname_rep << ": munmaping region." << endl;
#ifdef HAVE_MMAP
::munmap(buffer_repp, flength_rep);
::close(fd_rep);
#endif
}
void ECA_FILE_IO_MMAP::read_to_buffer(void* obuf, off_t bytes) {
if (is_file_ready() == false) {
bytes_rep = 0;
file_ended_rep = true;
return;
}
if (fposition_rep + bytes > flength_rep)
bytes = flength_rep - fposition_rep;
// cerr << fname_rep << ": mmap read " << fposition_rep << " -> ";
std::memcpy(obuf, buffer_repp + fposition_rep, bytes);
// cerr << fposition_rep + bytes << "." << endl;
set_file_position(fposition_rep + bytes, false);
bytes_rep = bytes;
}
void ECA_FILE_IO_MMAP::write_from_buffer(void* obuf, off_t bytes) {
if (is_file_ready() == false) {
bytes_rep = 0;
file_ended_rep = true;
return;
}
if (fposition_rep + bytes > flength_rep)
bytes = flength_rep - fposition_rep;
std::memcpy(buffer_repp + fposition_rep, obuf, bytes);
set_file_position(fposition_rep + bytes, false);
bytes_rep = bytes;
}
off_t ECA_FILE_IO_MMAP::file_bytes_processed(void) const { return(bytes_rep); }
bool ECA_FILE_IO_MMAP::is_file_ready(void) const { return(file_ready_rep); }
bool ECA_FILE_IO_MMAP::is_file_ended(void) const { return(file_ended_rep); }
bool ECA_FILE_IO_MMAP::is_file_error(void) const { return(!file_ready_rep && !file_ended_rep); }
void ECA_FILE_IO_MMAP::set_file_position(off_t newpos, bool seek) {
fposition_rep = newpos;
if (fposition_rep >= flength_rep) {
fposition_rep = flength_rep;
file_ready_rep = false;
file_ended_rep = true;
}
else {
file_ready_rep = true;
file_ended_rep = false;
}
}
void ECA_FILE_IO_MMAP::set_file_position_advance(off_t fw) {
set_file_position(fposition_rep + fw, false);
}
void ECA_FILE_IO_MMAP::set_file_position_end(void) {
fposition_rep = get_file_length();
}
off_t ECA_FILE_IO_MMAP::get_file_position(void) const { return(fposition_rep); }
off_t ECA_FILE_IO_MMAP::get_file_length(void) const {
struct stat stattemp;
fstat(fd_rep, &stattemp);
return((off_t)stattemp.st_size);
}