non/nonlib/file.C

216 lines
4.6 KiB
C

/*******************************************************************************/
/* Copyright (C) 2008 Jonathan Moore Liles */
/* */
/* 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; see the file COPYING. If not,write to the Free Software */
/* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/*******************************************************************************/
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
unsigned long
modification_time ( const char *file )
{
struct stat st;
if ( stat( file, &st ) )
return 0;
return st.st_mtime;
}
/** returns /true/ if /file1/ is newer than /file2/ (or file2 doesn't exist) */
bool
newer ( const char *file1, const char *file2 )
{
return modification_time( file1 ) > modification_time( file2 );
}
unsigned long
size ( const char *file )
{
struct stat st;
if ( stat( file, &st ) )
return 0;
return st.st_size;
}
int
exists ( const char *name )
{
struct stat st;
return 0 == stat( name, &st );
}
bool
acquire_lock ( int *lockfd, const char *filename )
{
struct flock fl;
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
fl.l_start = 0;
fl.l_len = 0;
*lockfd = ::creat( filename, 0777 );
if ( fcntl( *lockfd, F_SETLK, &fl ) != 0 )
return false;
return true;
}
void
release_lock ( int *lockfd, const char *filename )
{
unlink( filename );
::close( *lockfd );
*lockfd = 0;
}
int
backwards_fgetc ( FILE *fp )
{
int c;
if ( fseek( fp, -1, SEEK_CUR ) != 0 )
return -1;
c = fgetc( fp );
fseek( fp, -1, SEEK_CUR );
return c;
}
char *
backwards_fgets ( char *s, int size, FILE *fp )
{
if ( fseek( fp, -1, SEEK_CUR ) != 0 )
return NULL;
int c;
while ( ( c = backwards_fgetc( fp ) ) >= 0 )
if ( '\n' == c )
break;
long here = ftell( fp );
fseek( fp, 1, SEEK_CUR );
char *r = fgets( s, size, fp );
fseek( fp, here, SEEK_SET );
return r;
}
/** update the modification time of file referred to by /fd/ */
void
touch ( int fd )
{
struct stat st;
fstat( fd, &st );
fchmod( fd, st.st_mode );
}
/** write a single string to a file */
void
write_line ( const char *dir, const char *name, const char *value )
{
char path[512];
snprintf( path, sizeof( path ), "%s/%s", dir, name );
FILE *fp = fopen( path, "w" );
if ( ! fp )
return;
fputs( value, fp );
fclose( fp );
}
/** write a single string to a file */
void
read_line ( const char *dir, const char *name, char **value )
{
char path[512];
*value = 0;
snprintf( path, sizeof( path ), "%s/%s", dir, name );
FILE *fp = fopen( path, "r" );
if ( ! fp )
return;
*value = (char*)malloc( 512 );
fgets( *value, 512, fp );
fclose( fp );
}
#include <sys/statvfs.h>
/** return the number of blocks free on filesystem containing file named /file/ */
unsigned long
free_space ( const char *file )
{
struct statvfs st;
memset( &st, 0, sizeof( st ) );
statvfs( file, &st );
return st.f_bfree;
}
/** return the total number of blocks on filesystem containing file named /file/ */
unsigned long
total_space ( const char *file )
{
struct statvfs st;
memset( &st, 0, sizeof( st ) );
statvfs( file, &st );
return st.f_blocks;
}
/** return the percentage of usage on filesystem containing file named /file/ */
int
percent_used ( const char *file )
{
const size_t ts = total_space( file );
return 100 - ( ts ? free_space( file ) * 100 / ts : 0 );
}