/*
* C_lib Copyright (C) 2021 Wael Karram.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 3 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

/* This header defines a double-linked-list and related functions. */
/* Use the double nodes. */
#include <stdlib.h> /* Used in allocations and deallocations. */
#include <math.h>
#include <string.h>
/* Include assert.h to allow code generation, but only run with debug flag. */
#ifdef DEBUG
#ifndef NDEBUG
#define NDEBUG
#endif /* NDEBUG. */
#endif /* DEBUG. */
#include <assert.h>
/* Include the void swapping. */
#include "../utils/swap_void.c"



#ifndef VECTOR_H
#define VECTOR_H
/* Constants. */
/* Growth constant, for the power. */
#define GROWTH_CONSTANT_VECTOR_C			2
/* Inital power. */
#define INITIAL_POWER_VECTOR_C				3
/* Function errror/return code on success. */
#define SUCCESS_CODE_VECTOR_C				1
/* Function errror/return code on failure. */
#define FAILURE_CODE_VECTOR_C				0
/* Function errror/return code on failure to find index. */
#define INDEX_NOT_FOUND_CODE_VECTOR_C			-1
/* Function errror/return code on invalid input. */
#define INVALID_INPUT_CODE_VECTOR_C			-2
/* Function errror/return code on invalid input. */
#define INVALID_FREE_FUNCTION_POINTER			-3
/* Error code returned when input fails sanity check. */
#define CODE_FREE_SUCCESS_MALFORMED_VECTOR_C		-1
/* Check code for growing the vector. */
#define CODE_GROW_VECTOR_C				1
/* Check code for keeping the vector as is. */
#define CODE_KEEP_VECTOR_C				0
/* Check code for shrinking the vector. */
#define CODE_SHRINK_VECTOR_C				-1
/* Error code for when write succeeds and vector grow fails. */
#define WRITE_SUCCESS_VECTOR_GROW_FAIL_VECTOR_C		3
/* Error code for when delete succeeds and vector shrink fails. */
#define DELETE_SUCCESS_VECTOR_SHRINK_FAIL_VECTOR_C	4
/* Error code to indicate allocation failure. */
#define ALLOC_FAILURE_VECTOR_C				5
/* Used to calculate the whole when checking size-changes. */
#define THRESHOLD_WHOLE_VECTOR_C			1.0
/* The threshold used to grow the vector. */
#define THRESHOLD_GROW_VECTOR_C				0.75
/* The threshold used to shrink the vector. */
#define THRESHOLD_SHRINK_VECTOR_C			0.25
/* Define the initial index for the last element. */
#define LAST_ELEMENT_EMPTY_INDEX_VECTOR_C		0
/* Boolean Logic. */
#define TRUE						1
#define FALSE						0


/* Useful typedef for void pointers to make it simpler to deal with. */
typedef void* void_ptr;

/* The vector's struct. */
typedef struct vector {
	/* Stores the current power used to compute the length. */
	int power;
	/* Stores the vector's length. */
	size_t length;
	/* Stores the size of a single element. */
	size_t element_size;
	/* Stores the index of the last used element (inclusive!). */
	size_t last_element;
	/* Stores whethere or not the vector is empty. */
	char empty;
	/* Stores a pointer to the array. */
	void_ptr *array;
} vector_t;

/* Function declarations. */
/* This function initializes a new empty vector. */
static inline vector_t* initialize_vector();
/* This function appends to the vector. */
static inline int append_to_vector(vector_t* vector, void* const data);
/* This function prepends to the vector. */
static inline int prepend_to_vector(vector_t* const vector, void* const data);
/* This function reads from the vector at the given index. */
static inline void* read_from_vector(const vector_t* const vector, const size_t index);
/* This function overwrites the value at the given index. */
static inline int write_to_vector(vector_t* const vector, const size_t index, void* const data);
/* This function frees the data at the given index (using the given free function, if NULL doesn't change it!) and marks the cell there as NULL. */
static inline void delete_from_vector(vector_t* const vector, const size_t index, void (*free_function)(const void*));
/* This function serializes the vector into an array! */
static inline void_ptr* serialize_vector(const vector_t* const vector);
/* This function copies a vector. */
static inline int copy_vector(vector_t *restrict source, vector_t **restrict destination);
/* This function frees a vector. */
static inline void free_vector(vector_t *vector, void (*free_function)(const void*));
/* Internal functions. */
/* This function checks if a vector needs to be grown. */
static inline int check_vector_grow(const vector_t* const vector, const double threshold);
/* This function checks if a vector needs to be shrunk. */
static inline int check_vector_shrink(const vector_t* const vector, const double threshold);
/* This function grows the vector, doesn't change the vector on failure. */
static inline int grow_vector(vector_t* const vector);
/* This function shrinks the vector, doesn't change the vector on failure. */
static inline int shrink_vector(vector_t* const vector);
/* This function compacts a vector by pushing all the NULLs to the end. */
static inline void compact_vector(vector_t* const vector);
/* This function creates a "gap" at the start of the vector. */
static inline void push_vector(const vector_t* const vector, const size_t gap_length);

#endif /* VECTOR_H */