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/* -*- c++ -*- */
/*
* Copyright 2002,2010,2013 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 "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
namespace gr {
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;
circular_file::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];
}
circular_file::~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
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
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
circular_file::reset_read_pointer()
{
d_bytes_read = 0;
}
} /* namespace gr */
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