source: mainline/uspace/app/bithenge/blob.c@ a54bd98

/*
 * Copyright (c) 2012 Sean Bartell
 * 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 bithenge
 * @{
 */
/**
 * @file
 * Raw binary blobs.
 */

#include <bool.h>
#include <errno.h>
#include <macros.h>
#include <mem.h>
#include <stdlib.h>
#include "blob.h"

/** Initialize a random access blob.
 * @memberof bithenge_blob_t
 * @param[out] blob The blob to initialize.
 * @param[in] ops Operations provided random access support. This pointer must
 * be valid until the blob is destroyed.
 * @return EOK on success or an error code from errno.h.
 */
int bithenge_new_random_access_blob(
                bithenge_blob_t *blob,
                const bithenge_random_access_blob_ops_t *ops) {
        blob->ops = ops;
        return EOK;
}

static int sequential_buffer(bithenge_sequential_blob_t *blob, aoff64_t end) {
        bool need_realloc = false;
        while (end > blob->buffer_size) {
                blob->buffer_size = max(4096, 2 * blob->buffer_size);
                need_realloc = true;
        }
        if (need_realloc) {
                char *buffer = realloc(blob->buffer, blob->buffer_size);
                if (!buffer)
                        return errno;
                blob->buffer = buffer;
        }
        size_t size = end - blob->data_size;
        int rc = blob->ops->read(blob, blob->buffer + blob->data_size, &size);
        if (rc != EOK)
                return rc;
        blob->data_size += size;
        return EOK;
}

static int sequential_size(bithenge_blob_t *base, aoff64_t *size) {
        bithenge_sequential_blob_t *blob = (bithenge_sequential_blob_t *)base;
        int rc = blob->ops->size(blob, size);
        if (rc != EOK) {
                rc = sequential_buffer(blob, blob->buffer_size);
                if (rc != EOK)
                        return rc;
                while (blob->data_size == blob->buffer_size) {
                        rc = sequential_buffer(blob, 2 * blob->buffer_size);
                        if (rc != EOK)
                                return rc;
                }
                *size = blob->data_size;
        }
        return EOK;
}

static int sequential_read(bithenge_blob_t *base, aoff64_t offset, char *buffer, aoff64_t *size) {
        bithenge_sequential_blob_t *blob = (bithenge_sequential_blob_t *)base;
        aoff64_t end = offset + *size;
        if (end > blob->data_size) {
                int rc = sequential_buffer(blob, end);
                if (rc != EOK)
                        return rc;
        }
        if (offset > blob->data_size)
                return EINVAL;
        *size = min(*size, blob->data_size - end);
        memcpy(buffer, blob->buffer + offset, *size);
        return EOK;
}

static int sequential_destroy(bithenge_blob_t *base) {
        bithenge_sequential_blob_t *blob = (bithenge_sequential_blob_t *)base;
        free(blob->buffer);
        return blob->ops->destroy(blob);
}

static const bithenge_random_access_blob_ops_t sequential_ops = {
        .size = sequential_size,
        .read = sequential_read,
        .destroy = sequential_destroy,
};

/** Initialize a sequential blob.
 * @memberof bithenge_sequential_blob_t
 * @param[out] blob The blob to initialize.
 * @param[in] ops Operations providing sequential access support. This pointer
 * must be valid until the blob is destroyed.
 * @return EOK on success or an error code from errno.h.
 */
int bithenge_new_sequential_blob(
                bithenge_sequential_blob_t *blob,
                const bithenge_sequential_blob_ops_t *ops) {
        int rc = bithenge_new_random_access_blob(&blob->base, &sequential_ops);
        if (rc != EOK)
                return rc;
        blob->ops = ops;
        blob->buffer = NULL; // realloc(NULL, ...) works like malloc
        blob->buffer_size = 0;
        blob->data_size = 0;
        return EOK;
}

/** @}
 */