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