/*
 * $Id: arraylist.c,v 1.4 2006/01/26 02:16:28 mclark Exp $
 *
 * Copyright (c) 2004, 2005 Metaparadigm Pte. Ltd.
 * Michael Clark <michael@metaparadigm.com>
 *
 * This library is free software; you can redistribute it and/or modify
 * it under the terms of the MIT license. See COPYING for details.
 *
 */

#include "config.h"

#include <limits.h>

#ifdef STDC_HEADERS
#include <stdlib.h>
#include <string.h>
#endif /* STDC_HEADERS */

#if defined(HAVE_STRINGS_H) && !defined(_STRING_H) && !defined(__USE_BSD)
#include <strings.h>
#endif /* HAVE_STRINGS_H */

#ifndef SIZE_T_MAX
#if SIZEOF_SIZE_T == SIZEOF_INT
#define SIZE_T_MAX UINT_MAX
#elif SIZEOF_SIZE_T == SIZEOF_LONG
#define SIZE_T_MAX ULONG_MAX
#elif SIZEOF_SIZE_T == SIZEOF_LONG_LONG
#define SIZE_T_MAX ULLONG_MAX
#else
#error Unable to determine size of size_t
#endif
#endif

#include "arraylist.h"

struct array_list *array_list_new(array_list_free_fn *free_fn)
{
	return array_list_new2(free_fn, ARRAY_LIST_DEFAULT_SIZE);
}

struct array_list *array_list_new2(array_list_free_fn *free_fn, int initial_size)
{
	struct array_list *arr;

	if (initial_size < 0 || (size_t)initial_size >= SIZE_T_MAX / sizeof(void *))
		return NULL;
	arr = (struct array_list *)malloc(sizeof(struct array_list));
	if (!arr)
		return NULL;
	arr->size = initial_size;
	arr->length = 0;
	arr->free_fn = free_fn;
	if (!(arr->array = (void **)malloc(arr->size * sizeof(void *))))
	{
		free(arr);
		return NULL;
	}
	return arr;
}

extern void array_list_free(struct array_list *arr)
{
	size_t i;
	for (i = 0; i < arr->length; i++)
		if (arr->array[i])
			arr->free_fn(arr->array[i]);
	free(arr->array);
	free(arr);
}

void *array_list_get_idx(struct array_list *arr, size_t i)
{
	if (i >= arr->length)
		return NULL;
	return arr->array[i];
}

static int array_list_expand_internal(struct array_list *arr, size_t max)
{
	void *t;
	size_t new_size;

	if (max < arr->size)
		return 0;
	/* Avoid undefined behaviour on size_t overflow */
	if (arr->size >= SIZE_T_MAX / 2)
		new_size = max;
	else
	{
		new_size = arr->size << 1;
		if (new_size < max)
			new_size = max;
	}
	if (new_size > (~((size_t)0)) / sizeof(void *))
		return -1;
	if (!(t = realloc(arr->array, new_size * sizeof(void *))))
		return -1;
	arr->array = (void **)t;
	arr->size = new_size;
	return 0;
}

int array_list_shrink(struct array_list *arr, size_t empty_slots)
{
	void *t;
	size_t new_size;

	if (empty_slots >= SIZE_T_MAX / sizeof(void *) - arr->length)
		return -1;
	new_size = arr->length + empty_slots;
	if (new_size == arr->size)
		return 0;
	if (new_size > arr->size)
		return array_list_expand_internal(arr, new_size);
	if (new_size == 0)
		new_size = 1;

	if (!(t = realloc(arr->array, new_size * sizeof(void *))))
		return -1;
	arr->array = (void **)t;
	arr->size = new_size;
	return 0;
}

int array_list_insert_idx(struct array_list *arr, size_t idx, void *data)
{
	size_t move_amount;

	if (idx >= arr->length)
		return array_list_put_idx(arr, idx, data);

	/* we're at full size, what size_t can support */
	if (arr->length == SIZE_T_MAX)
		return -1;

	if (array_list_expand_internal(arr, arr->length + 1))
		return -1;

	move_amount = (arr->length - idx) * sizeof(void *);
	memmove(arr->array + idx + 1, arr->array + idx, move_amount);
	arr->array[idx] = data;
	arr->length++;
	return 0;
}

//static inline int _array_list_put_idx(struct array_list *arr, size_t idx, void *data)
int array_list_put_idx(struct array_list *arr, size_t idx, void *data)
{
	if (idx > SIZE_T_MAX - 1)
		return -1;
	if (array_list_expand_internal(arr, idx + 1))
		return -1;
	if (idx < arr->length && arr->array[idx])
		arr->free_fn(arr->array[idx]);
	arr->array[idx] = data;
	if (idx > arr->length)
	{
		/* Zero out the arraylist slots in between the old length
		   and the newly added entry so we know those entries are
		   empty.
		   e.g. when setting array[7] in an array that used to be 
		   only 5 elements longs, array[5] and array[6] need to be
		   set to 0.
		 */
		memset(arr->array + arr->length, 0, (idx - arr->length) * sizeof(void *));
	}
	if (arr->length <= idx)
		arr->length = idx + 1;
	return 0;
}

int array_list_add(struct array_list *arr, void *data)
{
	/* Repeat some of array_list_put_idx() so we can skip several
	   checks that we know are unnecessary when appending at the end
	 */
	size_t idx = arr->length;
	if (idx > SIZE_T_MAX - 1)
		return -1;
	if (array_list_expand_internal(arr, idx + 1))
		return -1;
	arr->array[idx] = data;
	arr->length++;
	return 0;
}

void array_list_sort(struct array_list *arr, int (*compar)(const void *, const void *))
{
	qsort(arr->array, arr->length, sizeof(arr->array[0]), compar);
}

void *array_list_bsearch(const void **key, struct array_list *arr,
                         int (*compar)(const void *, const void *))
{
	return bsearch(key, arr->array, arr->length, sizeof(arr->array[0]), compar);
}

size_t array_list_length(struct array_list *arr)
{
	return arr->length;
}

int array_list_del_idx(struct array_list *arr, size_t idx, size_t count)
{
	size_t i, stop;

	/* Avoid overflow in calculation with large indices. */
	if (idx > SIZE_T_MAX - count)
		return -1;
	stop = idx + count;
	if (idx >= arr->length || stop > arr->length)
		return -1;
	for (i = idx; i < stop; ++i)
	{
		// Because put_idx can skip entries, we need to check if
		// there's actually anything in each slot we're erasing.
		if (arr->array[i])
			arr->free_fn(arr->array[i]);
	}
	memmove(arr->array + idx, arr->array + stop, (arr->length - stop) * sizeof(void *));
	arr->length -= count;
	return 0;
}