/*
 * $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 (__cdecl* 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 (__cdecl* 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;
}
