singly_linked_list_api.h

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// -------------------------------------------------------------------------------------------
// Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
// This file is part of the AWS CDI-SDK, licensed under the BSD 2-Clause "Simplified" License.
// License details at: https://github.com/aws/aws-cdi-sdk/blob/mainline/LICENSE
// -------------------------------------------------------------------------------------------
 
#ifndef CDI_SINGLY_LINKEDLIST_API_H__
#define CDI_SINGLY_LINKEDLIST_API_H__
 
#include <assert.h>
#include <stdbool.h>
#include <stddef.h>
 
//*********************************************************************************************************************
//***************************************** START OF DEFINITIONS AND TYPES ********************************************
//*********************************************************************************************************************
 
typedef struct CdiSinglyLinkedListEntry CdiSinglyLinkedListEntry;
 
struct CdiSinglyLinkedListEntry {
    struct CdiSinglyLinkedListEntry* next_ptr; 
};
 
typedef struct {
    CdiSinglyLinkedListEntry* head_ptr;  
    CdiSinglyLinkedListEntry* tail_ptr;  
    int num_entries;                     
} CdiSinglyLinkedList;
 
//*********************************************************************************************************************
//*********************************************** START OF VARIABLES **************************************************
//*********************************************************************************************************************
 
//*********************************************************************************************************************
//******************************************* START OF STATIC FUNCTIONS ***********************************************
//*********************************************************************************************************************
 
//*********************************************************************************************************************
//******************************************* START OF PUBLIC FUNCTIONS ***********************************************
//*********************************************************************************************************************
 
static inline void CdiSinglyLinkedListInit(CdiSinglyLinkedList* list_ptr)
{
    list_ptr->head_ptr    = NULL;
    list_ptr->tail_ptr    = NULL;
    list_ptr->num_entries = 0;
}
 
static inline void CdiSinglyLinkedListPushHead(CdiSinglyLinkedList* list_ptr,
                                               CdiSinglyLinkedListEntry* new_entry_ptr)
{
    new_entry_ptr->next_ptr = list_ptr->head_ptr;
    list_ptr->head_ptr = new_entry_ptr;
    if (list_ptr->tail_ptr == NULL) {
        list_ptr->tail_ptr = new_entry_ptr;
    }
    list_ptr->num_entries++;
}
 
static inline void CdiSinglyLinkedListPushTail(CdiSinglyLinkedList* list_ptr,
                                               CdiSinglyLinkedListEntry* new_entry_ptr)
{
    new_entry_ptr->next_ptr = NULL;
    if (list_ptr->tail_ptr != NULL) {
        list_ptr->tail_ptr->next_ptr = new_entry_ptr;
    }
    list_ptr->tail_ptr = new_entry_ptr;
    if (list_ptr->head_ptr == NULL) {
        list_ptr->head_ptr = new_entry_ptr;
    }
    list_ptr->num_entries++;
}
 
static inline CdiSinglyLinkedListEntry* CdiSinglyLinkedListPopHead(CdiSinglyLinkedList* list_ptr)
{
    CdiSinglyLinkedListEntry* p = list_ptr->head_ptr;
    if (p != NULL) {
        list_ptr->head_ptr = p->next_ptr;
        p->next_ptr = NULL;
 
        // Don't allow value to go negative.
        assert(list_ptr->num_entries >= 0);
        if (list_ptr->num_entries) {
            list_ptr->num_entries--;
        }
    }
    if (list_ptr->head_ptr == NULL) {
        list_ptr->tail_ptr = NULL;
    }
    return p;
}
 
static inline bool CdiSinglyLinkedListIsEmpty(const CdiSinglyLinkedList* list_ptr)
{
    return list_ptr->head_ptr == NULL;
}
 
static inline int CdiSinglyLinkedListSize(const CdiSinglyLinkedList* list_ptr)
{
    return list_ptr->num_entries;
}
 
static inline CdiSinglyLinkedListEntry* CdiSinglyLinkedListGetHead(const CdiSinglyLinkedList* list_ptr)
{
    return list_ptr->head_ptr;
}
 
static inline CdiSinglyLinkedListEntry* CdiSinglyLinkedListNextEntry(const CdiSinglyLinkedListEntry* entry_ptr)
{
    return entry_ptr->next_ptr;
}
 
#endif // CDI_SINGLY_LINKED_LIST_API_H__