source: mainline/uspace/lib/c/generic/adt/measured_strings.c@ d2b1040

/*
 * Copyright (c) 2009 Lukas Mejdrech
 * 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 libc
 *  @{
 */

/** @file
 * Character string with measured length implementation.
 * @see measured_strings.h
 */

#include <adt/measured_strings.h>
#include <malloc.h>
#include <mem.h>
#include <unistd.h>
#include <errno.h>
#include <err.h>
#include <async.h>

/** Creates a new measured string bundled with a copy of the given string
 * itself as one memory block.
 *
 * If the measured string is being freed, whole memory block is freed.
 * The measured string should be used only as a constant.
 *
 * @param[in] string    The initial character string to be stored.
 * @param[in] length    The length of the given string without the terminating
 *                      zero ('\0') character. If the length is zero, the actual
 *                      length is computed. The given length is used and
 *                      appended with the terminating zero ('\0') character
 *                      otherwise.
 * @returns             The new bundled character string with measured length.
 * @returns             NULL if there is not enough memory left.
 */
measured_string_ref
measured_string_create_bulk(const char *string, size_t length)
{
        measured_string_ref new;

        if (length == 0) {
                while (string[length])
                        length++;
        }
        new = (measured_string_ref) malloc(sizeof(measured_string_t) +
            (sizeof(char) * (length + 1)));
        if (!new)
                return NULL;

        new->length = length;
        new->value = ((char *) new) + sizeof(measured_string_t);
        // append terminating zero explicitly - to be safe
        memcpy(new->value, string, new->length);
        new->value[new->length] = '\0';

        return new;
}

/** Copies the given measured string with separated header and data parts.
 *
 * @param[in] source    The source measured string to be copied.
 * @returns             The copy of the given measured string.
 * @returns             NULL if the source parameter is NULL.
 * @returns             NULL if there is not enough memory left.
 */
measured_string_ref measured_string_copy(measured_string_ref source)
{
        measured_string_ref new;

        if (!source)
                return NULL;

        new = (measured_string_ref) malloc(sizeof(measured_string_t));
        if (new) {
                new->value = (char *) malloc(source->length + 1);
                if (new->value) {
                        new->length = source->length;
                        memcpy(new->value, source->value, new->length);
                        new->value[new->length] = '\0';
                        return new;
                }
                free(new);
        }

        return NULL;
}

/** Receives a measured strings array from a calling module.
 *
 * Creates the array and the data memory blocks.
 * This method should be used only while processing IPC messages as the array
 * size has to be negotiated in advance.
 *
 *  @param[out] strings The received measured strings array.
 *  @param[out] data    The measured strings data. This memory block stores the
 *                      actual character strings.
 *  @param[in] count    The size of the measured strings array.
 *  @returns            EOK on success.
 *  @returns            EINVAL if the strings or data parameter is NULL.
 *  @returns            EINVAL if the count parameter is zero (0).
 *  @returns            EINVAL if the sent array differs in size.
 *  @returns            EINVAL if there is inconsistency in sent measured
 *                      strings' lengths (should not occur).
 *  @returns            ENOMEM if there is not enough memory left.
 *  @returns            Other error codes as defined for the
 *                      async_data_write_finalize() function.
 */
int
measured_strings_receive(measured_string_ref *strings, char **data,
    size_t count)
{
        ERROR_DECLARE;

        size_t *lengths;
        size_t index;
        size_t length;
        char *next;
        ipc_callid_t callid;

        if ((!strings) || (!data) || (count <= 0))
                return EINVAL;

        lengths = (size_t *) malloc(sizeof(size_t) * (count + 1));
        if (!lengths)
                return ENOMEM;

        if ((!async_data_write_receive(&callid, &length)) ||
            (length != sizeof(size_t) * (count + 1))) {
                free(lengths);
                return EINVAL;
        }
        if (ERROR_OCCURRED(async_data_write_finalize(callid, lengths,
            length))) {
                free(lengths);
                return ERROR_CODE;
        }

        *data = malloc(lengths[count]);
        if (!*data) {
                free(lengths);
                return ENOMEM;
        }
        (*data)[lengths[count] - 1] = '\0';

        *strings = (measured_string_ref) malloc(sizeof(measured_string_t) *
            count);
        if (!*strings) {
                free(lengths);
                free(*data);
                return ENOMEM;
        }

        next = *data;
        for (index = 0; index < count; index++) {
                (*strings)[index].length = lengths[index];
                if (lengths[index] > 0) {
                        if (!async_data_write_receive(&callid, &length) ||
                            (length != lengths[index])) {
                                free(*data);
                                free(*strings);
                                free(lengths);
                                return EINVAL;
                        }
                        ERROR_PROPAGATE(async_data_write_finalize(callid, next,
                            lengths[index]));
                        (*strings)[index].value = next;
                        next += lengths[index];
                        *next++ = '\0';
                } else {
                        (*strings)[index].value = NULL;
                }
        }

        free(lengths);
        return EOK;
}

/** Computes the lengths of the measured strings in the given array.
 *
 * @param[in] strings   The measured strings array to be processed.
 * @param[in] count     The measured strings array size.
 * @returns             The computed sizes array.
 * @returns             NULL if there is not enough memory left.
 */
static size_t *prepare_lengths(const measured_string_ref strings, size_t count)
{
        size_t *lengths;
        size_t index;
        size_t length;

        lengths = (size_t *) malloc(sizeof(size_t) * (count + 1));
        if (!lengths)
                return NULL;

        length = 0;
        for (index = 0; index < count; index++) {
                lengths[index] = strings[index].length;
                length += lengths[index] + 1;
        }
        lengths[count] = length;
        return lengths;
}

/** Replies the given measured strings array to a calling module.
 *
 * This method should be used only while processing IPC messages as the array
 * size has to be negotiated in advance.
 *
 * @param[in] strings   The measured strings array to be transferred.
 * @param[in] count     The measured strings array size.
 * @returns             EOK on success.
 * @returns             EINVAL if the strings parameter is NULL.
 * @returns             EINVAL if the count parameter is zero (0).
 * @returns             EINVAL if the calling module does not accept the given
 *                      array size.
 * @returns             EINVAL if there is inconsistency in sent measured
 *                      strings' lengths (should not occur).
 * @returns             Other error codes as defined for the
 *                      async_data_read_finalize() function.
 */
int measured_strings_reply(const measured_string_ref strings, size_t count)
{
        ERROR_DECLARE;

        size_t *lengths;
        size_t index;
        size_t length;
        ipc_callid_t callid;

        if ((!strings) || (count <= 0))
                return EINVAL;

        lengths = prepare_lengths(strings, count);
        if (!lengths)
                return ENOMEM;

        if (!async_data_read_receive(&callid, &length) ||
            (length != sizeof(size_t) * (count + 1))) {
                free(lengths);
                return EINVAL;
        }
        if (ERROR_OCCURRED(async_data_read_finalize(callid, lengths, length))) {
                free(lengths);
                return ERROR_CODE;
        }
        free(lengths);

        for (index = 0; index < count; index++) {
                if (strings[index].length > 0) {
                        if (!async_data_read_receive(&callid, &length) ||
                            (length != strings[index].length)) {
                                return EINVAL;
                        }
                        ERROR_PROPAGATE(async_data_read_finalize(callid,
                            strings[index].value, strings[index].length));
                }
        }

        return EOK;
}

/** Receives a measured strings array from another module.
 *
 * Creates the array and the data memory blocks.
 * This method should be used only following other IPC messages as the array
 * size has to be negotiated in advance.
 *
 * @param[in] phone     The other module phone.
 * @param[out] strings  The returned measured strings array.
 * @param[out] data     The measured strings data. This memory block stores the
 *                      actual character strings.
 * @param[in] count     The size of the measured strings array.
 * @returns             EOK on success.
 * @returns             EINVAL if the strings or data parameter is NULL.
 * @returns             EINVAL if the phone or count parameter is not positive.
 * @returns             EINVAL if the sent array differs in size.
 * @returns             ENOMEM if there is not enough memory left.
 * @returns             Other error codes as defined for the
 *                      async_data_read_start() function.
 */
int
measured_strings_return(int phone, measured_string_ref *strings, char **data,
    size_t count)
{
        ERROR_DECLARE;

        size_t *lengths;
        size_t index;
        char *next;

        if ((phone < 0) || (!strings) || (!data) || (count <= 0))
                return EINVAL;

        lengths = (size_t *) malloc(sizeof(size_t) * (count + 1));
        if (!lengths)
                return ENOMEM;

        if (ERROR_OCCURRED(async_data_read_start(phone, lengths,
            sizeof(size_t) * (count + 1)))) {
                free(lengths);
                return ERROR_CODE;
        }

        *data = malloc(lengths[count]);
        if (!*data) {
                free(lengths);
                return ENOMEM;
        }

        *strings = (measured_string_ref) malloc(sizeof(measured_string_t) *
            count);
        if (!*strings) {
                free(lengths);
                free(*data);
                return ENOMEM;
        }

        next = *data;
        for (index = 0; index < count; index++) {
                (*strings)[index].length = lengths[index];
                if (lengths[index] > 0) {
                        ERROR_PROPAGATE(async_data_read_start(phone, next,
                            lengths[index]));
                        (*strings)[index].value = next;
                        next += lengths[index];
                        *next++ = '\0';
                } else {
                        (*strings)[index].value = NULL;
                }
        }

        free(lengths);
        return EOK;
}

/** Sends the given measured strings array to another module.
 *
 * This method should be used only following other IPC messages as the array
 * size has to be negotiated in advance.
 *
 * @param[in] phone     The other module phone.
 * @param[in] strings   The measured strings array to be transferred.
 * @param[in] count     The measured strings array size.
 * @returns             EOK on success.
 * @returns             EINVAL if the strings parameter is NULL.
 * @returns             EINVAL if the phone or count parameter is not positive.
 * @returns             Other error codes as defined for the
 *                      async_data_write_start() function.
 */
int
measured_strings_send(int phone, const measured_string_ref strings,
    size_t count)
{
        ERROR_DECLARE;

        size_t *lengths;
        size_t index;

        if ((phone < 0) || (!strings) || (count <= 0))
                return EINVAL;

        lengths = prepare_lengths(strings, count);
        if (!lengths)
                return ENOMEM;

        if (ERROR_OCCURRED(async_data_write_start(phone, lengths,
            sizeof(size_t) * (count + 1)))) {
                free(lengths);
                return ERROR_CODE;
        }

        free(lengths);

        for (index = 0; index < count; index++) {
                if (strings[index].length > 0) {
                        ERROR_PROPAGATE(async_data_write_start(phone,
                            strings[index].value, strings[index].length));
                }
        }

        return EOK;
}

/** @}
 */