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/* $Id: cxfileutils.c,v 1.7 2011/02/21 14:15:31 rpalsa Exp $
*
* This file is part of the ESO C Extension Library
* Copyright (C) 2001-2011 European Southern Observatory
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/*
* $Author: rpalsa $
* $Date: 2011/02/21 14:15:31 $
* $Revision: 1.7 $
* $Name: cpl-6_1_1 $
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#include <sys/stat.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#include "cxmemory.h"
#include "cxfileutils.h"
#ifdef STAT_MACROS_BROKEN
#undef S_ISDIR
#endif
#if !defined S_ISDIR && defined S_IFMT && defined S_IFDIR
#define S_ISDIR(mode) ((mode) & S_IFMT == S_IFDIR)
#endif
/**
* @defgroup cxfileutils File Utilities
*
* The module provides a collection of useful file and file path related
* utility functions.
*
* @par Synopsis:
* @code
* #include <cxfileutils.h>
* @endcode
*/
/**@{*/
/**
* @brief
* Get the maximum length of a path relative to the given directory.
*
* @param path Directory name.
*
* @return Maximum path length.
*
* The function returns the maximum length a relative path when @em path
* is the current working directory. To get the maximum possible length
* of an absolute path pass "/" for @em path, but see the note below.
* The size is determined through the @b pathconf() function, or if this
* is not available the maximum length is simply set to the ad hoc length
* of 4095 characters.
*
* @note
* The maximum length of a pathname depends on the underlying filesystem.
* This means that the method to determine the maximum possible length
* of an absolute pathname might be incorrect if the root directory
* and the actual location of the file under consideration are located
* on different filesystems.
*/
cxlong
cx_path_max(const cxchar *path)
{
cxlong sz = 4095;
if (path == NULL) return sz;
#ifdef HAVE_PATHCONF
sz = pathconf(path, _PC_PATH_MAX);
#endif
return sz;
}
/**
* @brief
* Allocate a buffer suitable for storing a relative pathname staring at
* a given directory.
*
* @param path Directory name the relative path should start from.
*
* @return Allocated buffer of appropriate size, or @c NULL in case of an
* error.
*
* The function determines the maximum possible length of a relative
* path name when @em path is the current working directory. A buffer
* with the appropriate length for the relative pathname including the
* trailing zero. The argument @em path must be the name of an existing,
* or the function fails. The allocated buffer can be destroyed by calling
* @b cx_free().
*
* IF the string "/" is used for @em path the returned buffer will have the
* maximum length possible for an absolute path supported by the system
* (but see the note for @b cx_path_max() for pitfalls).
*/
cxchar *
cx_path_alloc(const char *path)
{
#ifdef S_ISDIR
struct stat sb;
#endif
if (!path || path[0] == '\0')
return NULL;
#ifdef S_ISDIR
/*
* Check that path is a directory
*/
if (stat(path, &sb) != 0 || !S_ISDIR(sb.st_mode))
return NULL;
#endif
return cx_calloc(cx_path_max(path) + 1, sizeof(cxchar));
}
/**@}*/
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