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/**
* @file
*
* @brief IMFS Read Next Directory
* @ingroup IMFS
*/
/*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include "imfs.h"
#include <string.h>
#include <dirent.h>
ssize_t imfs_dir_read(
rtems_libio_t *iop,
void *buffer,
size_t count
)
{
/*
* Read up to element iop->offset in the directory chain of the
* imfs_jnode_t struct for this file descriptor.
*/
const IMFS_directory_t *dir;
const rtems_chain_node *node;
const rtems_chain_control *entries;
struct dirent *dir_ent;
ssize_t bytes_transferred;
off_t current_entry;
off_t first_entry;
off_t last_entry;
rtems_filesystem_instance_lock( &iop->pathinfo );
dir = IMFS_iop_to_directory( iop );
entries = &dir->Entries;
/* Move to the first of the desired directory entries */
bytes_transferred = 0;
first_entry = iop->offset;
/* protect against using sizes that are not exact multiples of the */
/* -dirent- size. These could result in unexpected results */
last_entry = first_entry
+ (count / sizeof( *dir_ent )) * sizeof( *dir_ent );
/* The directory was not empty so try to move to the desired entry in chain*/
for (
current_entry = 0,
node = rtems_chain_immutable_first( entries );
current_entry < last_entry
&& !rtems_chain_is_tail( entries, node );
current_entry += sizeof( *dir_ent ),
node = rtems_chain_immutable_next( node )
) {
if( current_entry >= first_entry ) {
const IMFS_jnode_t *imfs_node = (const IMFS_jnode_t *) node;
dir_ent = (struct dirent *) ((char *) buffer + bytes_transferred);
/* Move the entry to the return buffer */
dir_ent->d_off = current_entry;
dir_ent->d_reclen = sizeof( *dir_ent );
dir_ent->d_ino = IMFS_node_to_ino( imfs_node );
dir_ent->d_namlen = strlen( imfs_node->name );
memcpy( dir_ent->d_name, imfs_node->name, dir_ent->d_namlen + 1 );
iop->offset += sizeof( *dir_ent );
bytes_transferred += (ssize_t) sizeof( *dir_ent );
}
}
rtems_filesystem_instance_unlock( &iop->pathinfo );
return bytes_transferred;
}
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