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/*
 * Copyright (c) 2007 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_ops.c
 * @brief   Implementation of VFS operations for the FAT file system server.
 */

#include "fat.h"
#include "../../vfs/vfs.h"
#include <ipc/ipc.h>
#include <async.h>
#include <errno.h>

#define PLB_GET_CHAR(i)     (plb_ro[(i) % PLB_SIZE])

#define FAT_NAME_LEN        8
#define FAT_EXT_LEN     3

#define FAT_PAD         ' ' 

#define FAT_DENTRY_UNUSED   0x00
#define FAT_DENTRY_E5_ESC   0x05
#define FAT_DENTRY_DOT      0x2e
#define FAT_DENTRY_ERASED   0xe5

/** Compare one component of path to a directory entry.
 *
 * @param dentry    Directory entry to compare the path component with.
 * @param start     Index into PLB where the path component starts.
 * @param last      Index of the last character of the path in PLB.
 *
 * @return      Zero on failure or delta such that (index + delta) %
 *          PLB_SIZE points to a new path component in PLB.
 */
static unsigned match_path_component(fat_dentry_t *dentry, unsigned start,
    unsigned last)
{
    unsigned cur;   /* current position in PLB */
    int pos;    /* current position in dentry->name or dentry->ext */
    bool name_processed = false;
    bool dot_processed = false;
    bool ext_processed = false;

    if (last < start)
        last += PLB_SIZE;
    for (pos = 0, cur = start; (cur <= last) && (PLB_GET_CHAR(cur) != '/');
        pos++, cur++) {
        if (!name_processed) {
            if ((pos == FAT_NAME_LEN - 1) ||
                (dentry->name[pos + 1] == FAT_PAD)) {
                    /* this is the last character in name */
                name_processed = true;
            }
            if (dentry->name[0] == FAT_PAD) {
                /* name is empty */
                name_processed = true;
            } else if ((pos == 0) && (dentry->name[pos] ==
                FAT_DENTRY_E5_ESC)) {
                if (PLB_GET_CHAR(cur) == 0xe5)
                    continue;
                else
                    return 0;   /* character mismatch */
            } else {
                if (PLB_GET_CHAR(cur) == dentry->name[pos])
                    continue;
                else
                    return 0;   /* character mismatch */
            }
        }
        if (!dot_processed) {
            dot_processed = true;
            pos = -1;
            if (PLB_GET_CHAR(cur) != '.')
                return 0;
            continue;
        }
        if (!ext_processed) {
            if ((pos == FAT_EXT_LEN - 1) ||
                (dentry->ext[pos + 1] == FAT_PAD)) {
                /* this is the last character in ext */
                ext_processed = true;
            }
            if (dentry->ext[0] == FAT_PAD) {
                /* ext is empty; the match will fail */
                ext_processed = true;
            } else if (PLB_GET_CHAR(cur) == dentry->ext[pos]) {
                continue;
            } else {
                /* character mismatch */
                return 0;
            }
        }
        return 0;   /* extra characters in the component */
    }
    if (ext_processed || (name_processed && dentry->ext[0] == FAT_PAD))
        return cur - start;
    else
        return 0;
}

void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
{
    int first = IPC_GET_ARG1(*request);
    int second = IPC_GET_ARG2(*request);
    int dev_handle = IPC_GET_ARG3(*request);

    
}

/**
 * @}
 */