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/*
* Copyright (c) 2017 Cisco and/or its affiliates.
* Licensed 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.
*/
/**
* @file metis_TlvExtent.h
* @brief Defines the extent structure used to map a TLV packet
*
* In MetisTlvSkeleton, all the pertinent fields used by Metis are stored by their extent range in the
* received packet buffer. An extent is (offset, length).
*
*/
#ifndef Metis_metis_tlv_Extent_h
#define Metis_metis_tlv_Extent_h
#include <stdint.h>
#include <stdbool.h>
/**
* Stores the location of a field within a buffer.
* The values are usually in host byte order.
*/
typedef struct metis_tlv_extent {
uint16_t offset;
uint16_t length;
} MetisTlvExtent;
/**
* Used to detect a "not found" or "not present" condition.
* Equal to { 0x0, 0x0 }, which is an invalid extent value.
*/
extern const MetisTlvExtent metisTlvExtent_NotFound;
/**
* Determine if two MetisTlvExtent instances are equal.
*
* The following equivalence relations on non-null `MetisTlvExtent` instances are maintained:
*
* * It is reflexive: for any non-null reference value x, `MetisTlvExtent_Equals(x, x)`
* must return true.
*
* * It is symmetric: for any non-null reference values x and y,
* `metisTlvExtent_Equals(x, y)` must return true if and only if
* `metisTlvExtent_Equals(y, x)` returns true.
*
* * It is transitive: for any non-null reference values x, y, and z, if
* `metisTlvExtent_Equals(x, y)` returns true and
* `metisTlvExtent_Equals(y, z)` returns true,
* then `metisTlvExtent_Equals(x, z)` must return true.
*
* * It is consistent: for any non-null reference values x and y, multiple
* invocations of `metisTlvExtent_Equals(x, y)` consistently return true or
* consistently return false.
*
* * For any non-null reference value x, `metisTlvExtent_Equals(x, NULL)` must
* return false.
*
* @param a A pointer to a `MetisTlvExtent` instance.
* @param b A pointer to a `MetisTlvExtent` instance.
* @return true if the two `MetisTlvExtent` instances are equal.
*
* Example:
* @code
* {
* MetisTlvExtent *a = { .offset = 5, .length = 7 };
* MetisTlvExtent *b = { .offset = 5, .length = 8 };
*
* if (metisTlvExtent_Equals(a, b)) {
* // true
* } else {
* // false (this is the block executed)
* }
* }
* @endcode
*/
bool metisTlvExtent_Equals(const MetisTlvExtent *a, const MetisTlvExtent *b);
#endif // Metis_metis_tlv_Extent_h
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