source: mainline/uspace/srv/fs/fat/fat_directory.c@ 7a819535

/*
 * Copyright (c) 2008 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup fs
 * @{
 */ 

/**
 * @file        fat_directory.c
 * @brief       Functions that work with FAT directory.
 */

#include "fat_directory.h"
#include <libblock.h>
#include <errno.h>
#include <byteorder.h>

int fat_directory_open(fat_node_t *nodep, fat_directory_t *di)
{
        di->nodep = nodep;      
        if (di->nodep->type != FAT_DIRECTORY)
                return EINVAL;

        di->bs = block_bb_get(di->nodep->idx->devmap_handle);
        di->blocks = di->nodep->size / BPS(di->bs);
        di->b = NULL;
        di->pos = 0;
        di->bnum = 0;
        di->last = false;

        di->lfn_utf16[0] = '\0';
        di->lfn_offset = 0;
        di->lfn_size = 0;
        di->long_entry = false;
        di->long_entry_count = 0;
        di->checksum=0;

        return EOK;
}

int fat_directory_close(fat_directory_t *di)
{
        int rc=EOK;
        
        if (di->b)
                rc = block_put(di->b);
        
        return rc;
}

int fat_directory_scan(fat_directory_t *di, fat_dentry_t **d)
{
        uint32_t i;
        int rc;
        
        i = (di->pos * sizeof(fat_dentry_t)) / BPS(di->bs);
        if (i < di->blocks) {
                if (di->b && di->bnum != i) {
                        block_put(di->b);
                        di->b = NULL;
                }
                if (!di->b) {
                        rc = fat_block_get(&di->b, di->bs, di->nodep, i, BLOCK_FLAGS_NONE);
                        if (rc != EOK) {
                                di->b = NULL;
                                return rc;
                        }
                        di->bnum = i;
                }
                aoff64_t o = di->pos % (BPS(di->bs) / sizeof(fat_dentry_t));
                *d = ((fat_dentry_t *)di->b->data) + o;
                di->pos+=1;
                return EOK;
        }
        return ENOENT;
}

int fat_directory_read(fat_directory_t *di, char *name, fat_dentry_t **de)
{
        fat_dentry_t *d = NULL;

        while (fat_directory_scan(di, &d) == EOK && d) {
                switch (fat_classify_dentry(d)) {
                case FAT_DENTRY_LAST:
                        di->long_entry_count = 0;
                        di->long_entry = false;
                        return ENOENT;
                case FAT_DENTRY_LFN:
                        if (di->long_entry) {
                                /* We found long entry */
                                di->long_entry_count--;
                                if ((FAT_LFN_ORDER(d) == di->long_entry_count) && 
                                        (di->checksum == FAT_LFN_CHKSUM(d))) {
                                        /* Right order! */
                                        fat_lfn_copy_entry(d, di->lfn_utf16, &di->lfn_offset);
                                } else {
                                        /* Something wrong with order. Skip this long entries set */
                                        di->long_entry_count = 0;
                                        di->long_entry = false;
                                }
                        } else {
                                if (FAT_IS_LFN(d)) {
                                        /* We found Last long entry! */
                                        if (FAT_LFN_COUNT(d) <= FAT_LFN_MAX_COUNT) {
                                                di->long_entry = true;
                                                di->long_entry_count = FAT_LFN_COUNT(d);
                                                di->lfn_size = (FAT_LFN_ENTRY_SIZE * 
                                                        (FAT_LFN_COUNT(d) - 1)) + fat_lfn_size(d);
                                                di->lfn_offset = di->lfn_size;
                                                fat_lfn_copy_entry(d, di->lfn_utf16, &di->lfn_offset);
                                                di->checksum = FAT_LFN_CHKSUM(d);
                                        }
                                }
                        }
                        break;
                case FAT_DENTRY_VALID:
                        if (di->long_entry && 
                                (di->checksum == fat_dentry_chksum(d->name))) {
                                int rc;
                                rc = fat_lfn_convert_name(di->lfn_utf16, di->lfn_size, 
                                        (uint8_t*)name, FAT_LFN_NAME_SIZE);
                                if (rc!=EOK)
                                        fat_dentry_name_get(d, name);
                        }
                        else
                                fat_dentry_name_get(d, name);
                        
                        *de = d;
                        di->long_entry_count = 0;
                        di->long_entry = false;
                        return EOK;
                default:
                case FAT_DENTRY_SKIP:
                case FAT_DENTRY_FREE:
                        di->long_entry_count = 0;
                        di->long_entry = false;
                        break;
                }
        }
        return ENOENT;
}


/**
 * @}
 */