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/* -*- c++ -*- */
/*
* Copyright 2002,2010 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio 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 3, or (at your option)
* any later version.
*
* GNU Radio 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 GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <gr_circular_file.h>
#include <unistd.h>
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include <algorithm>
#include <stdio.h>
#include <string.h>
#ifdef HAVE_IO_H
#include <io.h>
#endif
static const int HEADER_SIZE = 4096;
static const int HEADER_MAGIC = 0xEB021026;
static const int HD_MAGIC = 0;
static const int HD_HEADER_SIZE = 1; // integer offsets into header
static const int HD_BUFFER_SIZE = 2;
static const int HD_BUFFER_BASE = 3;
static const int HD_BUFFER_CURRENT = 4;
gr_circular_file::gr_circular_file (const char *filename,
bool writable, int size)
: d_fd (-1), d_header (0), d_buffer (0), d_mapped_size (0), d_bytes_read (0)
{
int mm_prot;
if (writable){
#ifdef HAVE_MMAP
mm_prot = PROT_READ | PROT_WRITE;
#endif
d_fd = open (filename, O_CREAT | O_RDWR | O_TRUNC, 0664);
if (d_fd < 0){
perror (filename);
exit (1);
}
#ifdef HAVE_MMAP /* FIXME */
if(ftruncate (d_fd, size + HEADER_SIZE) != 0) {
perror (filename);
exit (1);
}
#endif
}
else {
#ifdef HAVE_MMAP
mm_prot = PROT_READ;
#endif
d_fd = open (filename, O_RDONLY);
if (d_fd < 0){
perror (filename);
exit (1);
}
}
struct stat statbuf;
if (fstat (d_fd, &statbuf) < 0){
perror (filename);
exit (1);
}
if (statbuf.st_size < HEADER_SIZE){
fprintf (stderr, "%s: file too small to be circular buffer\n", filename);
exit (1);
}
d_mapped_size = statbuf.st_size;
#ifdef HAVE_MMAP
void *p = mmap (0, d_mapped_size, mm_prot, MAP_SHARED, d_fd, 0);
if (p == MAP_FAILED){
perror ("gr_circular_file: mmap failed");
exit (1);
}
d_header = (int *) p;
#else
perror ("gr_circular_file: mmap unsupported by this system");
exit (1);
#endif
if (writable){ // init header
if (size < 0){
fprintf (stderr, "gr_circular_buffer: size must be > 0 when writable\n");
exit (1);
}
d_header[HD_MAGIC] = HEADER_MAGIC;
d_header[HD_HEADER_SIZE] = HEADER_SIZE;
d_header[HD_BUFFER_SIZE] = size;
d_header[HD_BUFFER_BASE] = HEADER_SIZE; // right after header
d_header[HD_BUFFER_CURRENT] = 0;
}
// sanity check (the asserts are a bit unforgiving...)
assert (d_header[HD_MAGIC] == HEADER_MAGIC);
assert (d_header[HD_HEADER_SIZE] == HEADER_SIZE);
assert (d_header[HD_BUFFER_SIZE] > 0);
assert (d_header[HD_BUFFER_BASE] >= d_header[HD_HEADER_SIZE]);
assert (d_header[HD_BUFFER_BASE] + d_header[HD_BUFFER_SIZE] <= d_mapped_size);
assert (d_header[HD_BUFFER_CURRENT] >= 0 &&
d_header[HD_BUFFER_CURRENT] < d_header[HD_BUFFER_SIZE]);
d_bytes_read = 0;
d_buffer = (unsigned char *) d_header + d_header[HD_BUFFER_BASE];
}
gr_circular_file::~gr_circular_file ()
{
#ifdef HAVE_MMAP
if (munmap ((char *) d_header, d_mapped_size) < 0){
perror ("gr_circular_file: munmap");
exit (1);
}
#endif
close (d_fd);
}
bool
gr_circular_file::write (void *vdata, int nbytes)
{
unsigned char *data = (unsigned char *) vdata;
int buffer_size = d_header[HD_BUFFER_SIZE];
int buffer_current = d_header[HD_BUFFER_CURRENT];
while (nbytes > 0){
int n = std::min (nbytes, buffer_size - buffer_current);
memcpy (d_buffer + buffer_current, data, n);
buffer_current += n;
if (buffer_current >= buffer_size)
buffer_current = 0;
data += n;
nbytes -= n;
}
d_header[HD_BUFFER_CURRENT] = buffer_current;
return true;
}
int
gr_circular_file::read (void *vdata, int nbytes)
{
unsigned char *data = (unsigned char *) vdata;
int buffer_current = d_header[HD_BUFFER_CURRENT];
int buffer_size = d_header[HD_BUFFER_SIZE];
int total = 0;
nbytes = std::min (nbytes, buffer_size - d_bytes_read);
while (nbytes > 0){
int offset = (buffer_current + d_bytes_read) % buffer_size;
int n = std::min (nbytes, buffer_size - offset);
memcpy (data, d_buffer + offset, n);
data += n;
d_bytes_read += n;
total += n;
nbytes -= n;
}
return total;
}
void
gr_circular_file::reset_read_pointer ()
{
d_bytes_read = 0;
}
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