incubator-nuttx/libs/libc/uuid/lib_uuid_compare.c

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/****************************************************************************
* libs/libc/uuid/lib_uuid_compare.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <string.h>
#include <uuid.h>
/****************************************************************************
* Pre-processor definitions
****************************************************************************/
/* A macro used to improve the readability of uuid_compare(). */
#define DIFF_RETURN(a, b, field) \
do \
{ \
if ((a)->field != (b)->field) \
{ \
return (a)->field < (b)->field ? -1 : 1; \
} \
} \
while (0)
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* uuid_compare
*
* Description:
* Compare two UUIDs.
*
* See also:
* http://www.opengroup.org/onlinepubs/009629399/uuid_compare.htm
*
****************************************************************************/
int32_t uuid_compare(const uuid_t *a, const uuid_t *b, uint32_t *status)
{
if (status != NULL)
{
*status = uuid_s_ok;
}
/* Deal with NULL or equal pointers. */
if (a == b)
{
return 0;
}
if (a == NULL)
{
return uuid_is_nil(b, NULL) ? 0 : -1;
}
if (b == NULL)
{
return uuid_is_nil(a, NULL) ? 0 : 1;
}
/* We have to compare the hard way. */
DIFF_RETURN(a, b, time_low);
DIFF_RETURN(a, b, time_mid);
DIFF_RETURN(a, b, time_hi_and_version);
DIFF_RETURN(a, b, clock_seq_hi_and_reserved);
DIFF_RETURN(a, b, clock_seq_low);
return memcmp(a->node, b->node, sizeof(a->node));
}