/*
 * category: [data structure]
 * apply status: framework
 * edit status: not
 * build status: windows&linux
 * description:
 */

#ifndef ARRAY_H
#define ARRAY_H

#pragma once

#include "config.h"

#ifdef __cplusplus
extern "C" {
#endif

#include <stdarg.h>
#include <stdlib.h>
#include "memutil.h"

typedef struct array_header_t array_header_t;

/** An opaque array type */
struct array_header_t {
    /** The amount of memory allocated for each element of the array */
    int elt_size;
    /** The number of active elements in the array */
    int nelts;
    /** The number of elements already allocated in the array */
    int nalloc;
    /** The elements in the array, start address.*/
    char *elts;
};

/**
 * Determine if the array is empty (either NULL or having no elements)
 * @param a The array to check
 * @return True if empty, False otherwise
 */
TOOLKIT_API int array_empty(const array_header_t *a);

/**
 * Create an array
 * @param nelts the number of elements in the initial array
 * @param elt_size The size of each element in the array.
 * @return The new array
 */
TOOLKIT_API array_header_t *array_make(int nelts, int elt_size);

/**
 * destroy an array
 */
TOOLKIT_API void array_free(array_header_t *arr);


/**
 * Add a new element to an array (as a first-in, last-out stack)
 * @param arr The array to add an element to.
 * @return Location for the new element in the array.
 * @remark If there are no free spots in the array, then this function will
 *         allocate new space for the new element.
 */
TOOLKIT_API void *array_push(array_header_t *arr);

/** A helper macro for accessing a member of an array.
 *
 * @param ary the array
 * @param i the index into the array to return
 * @param type the type of the objects stored in the array
 *
 * @return the item at index i
 */
#define ARRAY_IDX(ary,i,type) (((type *)(ary)->elts)[i])

/** A helper macro for pushing elements into an array.
 *
 * @param ary the array
 * @param type the type of the objects stored in the array
 *
 * @return the location where the new object should be placed
 */
#define ARRAY_PUSH(ary,type) (*((type *)array_push(ary)))

/** A helper function to exchange two elem 
 * 
 * @param ary the array
 * @param type the type of the objects stored in the array
 * 
 * note: element type must be single type(not struct)
 */
#define ARRAY_XCHG(ary, x, y, type)	\
	do { \
		type tmp; \
		tmp = ARRAY_IDX(ary, x, type); \
		ARRAY_IDX(ary, x, type) = ARRAY_IDX(ary, y, type); \
		ARRAY_IDX(ary, y, type) = tmp; \
	} while (0)

#define ARRAY_XCHG_STRUCT(ary, i, j, type) \
	do { \
  	  type* ti = &ARRAY_IDX(ary, i, type); \
	  type* tj = &ARRAY_IDX(ary, j, type); \
	  type tmp; \
	  memcpy(&tmp, ti, sizeof(type)); \
	  memcpy(ti, tj, sizeof(type)); \
	  memcpy(tj, &tmp, sizeof(type)); \
	} while(0)

/** A helper by exchange position x with tail, witch type is a simple type
 *
 * @param ary the array
 * @param type the type of the objects stored in the array
 *
 * note: element type must be single type(not struct)
 */
#define ARRAY_XCHG_TAIL(ary, x, type)	\
	do { \
		if ((x) < (ary->nelts - 1)) { \
			ARRAY_XCHG(ary, x, ary->nelts - 1, type); \
		} \
	} while(0)

/** A helper by exchange position x with tail, witch type is a struct type */
#define ARRAY_XCHG_TAIL_STRUCT(ary, x, type)	\
	do { \
		if ((x) < (ary->nelts - 1)) { \
			ARRAY_XCHG_STRUCT(ary, x, ary->nelts - 1, type); \
		} \
	} while (0)

/** A helper delete x by exchange value with tail and pop out */
#define ARRAY_DEL(ary, x, type) \
	ARRAY_XCHG_TAIL(ary, x, type); \
	array_pop(ary);

/** A helper delete x by exchange value with tail and pop out, for struct type */
#define ARRAY_DEL_STRUCT(ary, i, type) \
	ARRAY_XCHG_TAIL_STRUCT(ary, i, type); \
	array_pop(ary);

/** helper for walk through each element */
#define ARRAY_FOR_EACH_ENTRY(pos, i, ary, type) \
	for (i = ary->nelts-1; pos = ARRAY_IDX(ary, i, type), i >= 0; --i) 

/** helper for walk through each element, can delete current pos */
#define ARRAY_FOR_EACH_ENTRY_SAFE	ARRAY_FOR_EACH_ENTRY

/**
 * Remove an element from an array (as a first-in, last-out stack)
 * @param arr The array to remove an element from.
 * @return Location of the element in the array.
 * @remark If there are no elements in the array, NULL is returned.
 */
TOOLKIT_API void * array_pop(array_header_t *arr);

/**
 * Remove all elements from an array.
 * @param arr The array to remove all elements from.
 * @remark As the underlying storage is allocated from a pool, no
 * memory is freed by this operation, but is available for reuse.
 */
TOOLKIT_API void array_clear(array_header_t *arr);

/**
 * Concatenate two arrays together
 * @param dst The destination array, and the one to go first in the combined 
 *            array
 * @param src The source array to add to the destination array
 */
TOOLKIT_API void array_cat(array_header_t *dst,const array_header_t *src);

/**
 * Copy the entire array
 * @param arr The array to copy
 * @return An exact copy of the array passed in
 * @remark The alternate apr_array_copy_hdr copies only the header, and arranges 
 *         for the elements to be copied if (and only if) the code subsequently
 *         does a push or arraycat.
 */
TOOLKIT_API array_header_t * array_copy(const array_header_t *arr);

/**
 * Reserves a minimum length of storage, allocating space if necessary
 * 
 */
TOOLKIT_API void array_reserve(array_header_t *arr, int cnt);

/**
 * destroy an array, and destry each element by free
 */
static __inline void array_free2(array_header_t *arr)
{
	int i;
	for (i = 0; i < arr->nelts; ++i) {
		free(ARRAY_IDX(arr, i, void*));
	}
	array_free(arr);
}

TOOLKIT_API void toolkit_array_free2(array_header_t *arr);

#ifdef __cplusplus
} // extern "C" {
#endif

#endif // ARRAY_H