source: mainline/uspace/lib/libblock/libblock.c@ fc840d9

/*
 * Copyright (c) 2008 Jakub Jermar 
 * Copyright (c) 2008 Martin Decky 
 * 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 libblock 
 * @{
 */ 
/**
 * @file
 * @brief
 */

#include "libblock.h" 
#include "../../srv/vfs/vfs.h"
#include "../../srv/rd/rd.h"
#include <errno.h>
#include <async.h>
#include <ipc/ipc.h>
#include <as.h>
#include <assert.h>

/** Read data from a block device.
 *
 * @param phone         Phone to be used to communicate with the device.
 * @param buffer        Communication buffer shared with the device.
 * @param bufpos        Pointer to the first unread valid offset within the
 *                      communication buffer.
 * @param buflen        Pointer to the number of unread bytes that are ready in
 *                      the communication buffer.
 * @param pos           Device position to be read.
 * @param dst           Destination buffer.
 * @param size          Size of the destination buffer.
 * @param block_size    Block size to be used for the transfer.
 *
 * @return              True on success, false on failure.
 */
bool blockread(int phone, void *buffer, off_t *bufpos, size_t *buflen,
    off_t *pos, void *dst, size_t size, size_t block_size)
{
        off_t offset = 0;
        size_t left = size;
        
        while (left > 0) {
                size_t rd;
                
                if (*bufpos + left < *buflen)
                        rd = left;
                else
                        rd = *buflen - *bufpos;
                
                if (rd > 0) {
                        /*
                         * Copy the contents of the communication buffer to the
                         * destination buffer.
                         */
                        memcpy(dst + offset, buffer + *bufpos, rd);
                        offset += rd;
                        *bufpos += rd;
                        *pos += rd;
                        left -= rd;
                }
                
                if (*bufpos == *buflen) {
                        /* Refill the communication buffer with a new block. */
                        ipcarg_t retval;
                        int rc = async_req_2_1(phone, RD_READ_BLOCK,
                            *pos / block_size, block_size, &retval);
                        if ((rc != EOK) || (retval != EOK))
                                return false;
                        
                        *bufpos = 0;
                        *buflen = block_size;
                }
        }
        
        return true;
}

int dev_phone = -1;             /* FIXME */
void *dev_buffer = NULL;        /* FIXME */

block_t *block_get(dev_handle_t dev_handle, off_t offset, size_t bs)
{
        /* FIXME */
        block_t *b;
        off_t bufpos = 0;
        size_t buflen = 0;
        off_t pos = offset * bs;

        assert(dev_phone != -1);
        assert(dev_buffer);

        b = malloc(sizeof(block_t));
        if (!b)
                return NULL;
        
        b->data = malloc(bs);
        if (!b->data) {
                free(b);
                return NULL;
        }
        b->size = bs;

        if (!blockread(dev_phone, dev_buffer, &bufpos, &buflen, &pos, b->data,
            bs, bs)) {
                free(b->data);
                free(b);
                return NULL;
        }

        return b;
}

void block_put(block_t *block)
{
        /* FIXME */
        free(block->data);
        free(block);
}

/** @}
 */