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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "cx/list.h"

#include <string.h>

// <editor-fold desc="Store Pointers Functionality">

static _Thread_local cx_compare_func cx_pl_cmpfunc_impl;

static int cx_pl_cmpfunc(
        const void *l,
        const void *r
) {
    void *const *lptr = l;
    void *const *rptr = r;
    const void *left = lptr == NULL ? NULL : *lptr;
    const void *right = rptr == NULL ? NULL : *rptr;
    return cx_pl_cmpfunc_impl(left, right);
}

static void cx_pl_hack_cmpfunc(const struct cx_list_s *list) {
    // cast away const - this is the hacky thing
    struct cx_collection_s *l = (struct cx_collection_s*) &list->collection;
    cx_pl_cmpfunc_impl = l->cmpfunc;
    l->cmpfunc = cx_pl_cmpfunc;
}

static void cx_pl_unhack_cmpfunc(const struct cx_list_s *list) {
    // cast away const - this is the hacky thing
    struct cx_collection_s *l = (struct cx_collection_s*) &list->collection;
    l->cmpfunc = cx_pl_cmpfunc_impl;
}

static void cx_pl_destructor(struct cx_list_s *list) {
    list->climpl->destructor(list);
}

static int cx_pl_insert_element(
        struct cx_list_s *list,
        size_t index,
        const void *element
) {
    return list->climpl->insert_element(list, index, &element);
}

static size_t cx_pl_insert_array(
        struct cx_list_s *list,
        size_t index,
        const void *array,
        size_t n
) {
    return list->climpl->insert_array(list, index, array, n);
}

static size_t cx_pl_insert_sorted(
        struct cx_list_s *list,
        const void *array,
        size_t n
) {
    cx_pl_hack_cmpfunc(list);
    size_t result = list->climpl->insert_sorted(list, array, n);
    cx_pl_unhack_cmpfunc(list);
    return result;
}

static int cx_pl_insert_iter(
        struct cx_iterator_s *iter,
        const void *elem,
        int prepend
) {
    struct cx_list_s *list = iter->src_handle.m;
    return list->climpl->insert_iter(iter, &elem, prepend);
}

static size_t cx_pl_remove(
        struct cx_list_s *list,
        size_t index,
        size_t num,
        void *targetbuf
) {
    return list->climpl->remove(list, index, num, targetbuf);
}

static void cx_pl_clear(struct cx_list_s *list) {
    list->climpl->clear(list);
}

static int cx_pl_swap(
        struct cx_list_s *list,
        size_t i,
        size_t j
) {
    return list->climpl->swap(list, i, j);
}

static void *cx_pl_at(
        const struct cx_list_s *list,
        size_t index
) {
    void **ptr = list->climpl->at(list, index);
    return ptr == NULL ? NULL : *ptr;
}

static ssize_t cx_pl_find_remove(
        struct cx_list_s *list,
        const void *elem,
        bool remove
) {
    cx_pl_hack_cmpfunc(list);
    ssize_t ret = list->climpl->find_remove(list, &elem, remove);
    cx_pl_unhack_cmpfunc(list);
    return ret;
}

static void cx_pl_sort(struct cx_list_s *list) {
    cx_pl_hack_cmpfunc(list);
    list->climpl->sort(list);
    cx_pl_unhack_cmpfunc(list);
}

static int cx_pl_compare(
        const struct cx_list_s *list,
        const struct cx_list_s *other
) {
    cx_pl_hack_cmpfunc(list);
    int ret = list->climpl->compare(list, other);
    cx_pl_unhack_cmpfunc(list);
    return ret;
}

static void cx_pl_reverse(struct cx_list_s *list) {
    list->climpl->reverse(list);
}

static void *cx_pl_iter_current(const void *it) {
    const struct cx_iterator_s *iter = it;
    void **ptr = iter->base.current_impl(it);
    return ptr == NULL ? NULL : *ptr;
}

static struct cx_iterator_s cx_pl_iterator(
        const struct cx_list_s *list,
        size_t index,
        bool backwards
) {
    struct cx_iterator_s iter = list->climpl->iterator(list, index, backwards);
    iter.base.current_impl = iter.base.current;
    iter.base.current = cx_pl_iter_current;
    return iter;
}

static cx_list_class cx_pointer_list_class = {
        cx_pl_destructor,
        cx_pl_insert_element,
        cx_pl_insert_array,
        cx_pl_insert_sorted,
        cx_pl_insert_iter,
        cx_pl_remove,
        cx_pl_clear,
        cx_pl_swap,
        cx_pl_at,
        cx_pl_find_remove,
        cx_pl_sort,
        cx_pl_compare,
        cx_pl_reverse,
        cx_pl_iterator,
};

void cxListStoreObjects(CxList *list) {
    list->collection.store_pointer = false;
    if (list->climpl != NULL) {
        list->cl = list->climpl;
        list->climpl = NULL;
    }
}

void cxListStorePointers(CxList *list) {
    list->collection.elem_size = sizeof(void *);
    list->collection.store_pointer = true;
    list->climpl = list->cl;
    list->cl = &cx_pointer_list_class;
}

// </editor-fold>

// <editor-fold desc="empty list implementation">

static void cx_emptyl_noop(__attribute__((__unused__)) CxList *list) {
    // this is a noop, but MUST be implemented
}

static void *cx_emptyl_at(
        __attribute__((__unused__)) const struct cx_list_s *list,
        __attribute__((__unused__)) size_t index
) {
    return NULL;
}

static ssize_t cx_emptyl_find_remove(
        __attribute__((__unused__)) struct cx_list_s *list,
        __attribute__((__unused__)) const void *elem,
        __attribute__((__unused__)) bool remove
) {
    return -1;
}

static bool cx_emptyl_iter_valid(__attribute__((__unused__)) const void *iter) {
    return false;
}

static CxIterator cx_emptyl_iterator(
        const struct cx_list_s *list,
        size_t index,
        __attribute__((__unused__)) bool backwards
) {
    CxIterator iter = {0};
    iter.src_handle.c = list;
    iter.index = index;
    iter.base.valid = cx_emptyl_iter_valid;
    return iter;
}

static cx_list_class cx_empty_list_class = {
        cx_emptyl_noop,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        cx_emptyl_noop,
        NULL,
        cx_emptyl_at,
        cx_emptyl_find_remove,
        cx_emptyl_noop,
        NULL,
        cx_emptyl_noop,
        cx_emptyl_iterator,
};

CxList cx_empty_list = {
        {
                NULL,
                NULL,
                0,
                0,
                NULL,
                NULL,
                NULL,
                false
        },
        &cx_empty_list_class,
        NULL
};

CxList *const cxEmptyList = &cx_empty_list;

// </editor-fold>

#define invoke_list_func(name, list, ...) \
    ((list)->climpl == NULL ? (list)->cl->name : (list)->climpl->name) \
    (list, __VA_ARGS__)

size_t cx_list_default_insert_array(
        struct cx_list_s *list,
        size_t index,
        const void *data,
        size_t n
) {
    size_t elem_size = list->collection.elem_size;
    const char *src = data;
    size_t i = 0;
    for (; i < n; i++) {
        if (0 != invoke_list_func(insert_element,
                                  list, index + i, src + (i * elem_size))) {
            return i;
        }
    }
    return i;
}

size_t cx_list_default_insert_sorted(
        struct cx_list_s *list,
        const void *sorted_data,
        size_t n
) {
    // corner case
    if (n == 0) return 0;

    size_t elem_size = list->collection.elem_size;
    cx_compare_func cmp = list->collection.cmpfunc;
    const char *src = sorted_data;

    // track indices and number of inserted items
    size_t di = 0, si = 0, inserted = 0;

    // search the list for insertion points
    for (; di < list->collection.size; di++) {
        const void *list_elm = invoke_list_func(at, list, di);

        // compare current list element with first source element
        // if less or equal, skip
        if (cmp(list_elm, src) <= 0) {
            continue;
        }

        // determine number of consecutive elements that can be inserted
        size_t ins = 1;
        const char *next = src;
        while (++si < n) {
            next += elem_size;
            // once we become larger than the list elem, break
            if (cmp(list_elm, next) <= 0) {
                break;
            }
            // otherwise, we can insert one more
            ins++;
        }

        // insert the elements at location si
        if (ins == 1) {
            if (0 != invoke_list_func(insert_element,
                                      list, di, src))
                return inserted;
        } else {
            size_t r = invoke_list_func(insert_array, list, di, src, ins);
            if (r < ins) return inserted + r;
        }
        inserted += ins;
        di += ins;

        // everything inserted?
        if (inserted == n) return inserted;
        src = next;
    }

    // insert remaining items
    if (si < n) {
        inserted += invoke_list_func(insert_array, list, di, src, n - si);
    }

    return inserted;
}

void cx_list_default_sort(struct cx_list_s *list) {
    size_t elem_size = list->collection.elem_size;
    size_t list_size = list->collection.size;
    void *tmp = malloc(elem_size * list_size);
    if (tmp == NULL) abort();

    // copy elements from source array
    char *loc = tmp;
    for (size_t i = 0; i < list_size; i++) {
        void *src = invoke_list_func(at, list, i);
        memcpy(loc, src, elem_size);
        loc += elem_size;
    }

    // qsort
    qsort(tmp, list_size, elem_size,
          list->collection.cmpfunc);

    // copy elements back
    loc = tmp;
    for (size_t i = 0; i < list_size; i++) {
        void *dest = invoke_list_func(at, list, i);
        memcpy(dest, loc, elem_size);
        loc += elem_size;
    }

    free(tmp);
}

int cx_list_default_swap(struct cx_list_s *list, size_t i, size_t j) {
    if (i == j) return 0;
    if (i >= list->collection.size) return 1;
    if (j >= list->collection.size) return 1;

    size_t elem_size = list->collection.elem_size;

    void *tmp = malloc(elem_size);
    if (tmp == NULL) return 1;

    void *ip = invoke_list_func(at, list, i);
    void *jp = invoke_list_func(at, list, j);

    memcpy(tmp, ip, elem_size);
    memcpy(ip, jp, elem_size);
    memcpy(jp, tmp, elem_size);

    free(tmp);

    return 0;
}

void cxListDestroy(CxList *list) {
    list->cl->destructor(list);
}

int cxListCompare(
        const CxList *list,
        const CxList *other
) {
    bool cannot_optimize = false;

    // if one is storing pointers but the other is not
    cannot_optimize |= list->collection.store_pointer ^ other->collection.store_pointer;

    // if one class is wrapped but the other is not
    cannot_optimize |= (list->climpl == NULL) ^ (other->climpl == NULL);

    // if the compare functions do not match or both are NULL
    if (!cannot_optimize) {
        cx_compare_func list_cmp = (cx_compare_func) (list->climpl != NULL ?
                                                      list->climpl->compare : list->cl->compare);
        cx_compare_func other_cmp = (cx_compare_func) (other->climpl != NULL ?
                                                       other->climpl->compare : other->cl->compare);
        cannot_optimize |= list_cmp != other_cmp;
        cannot_optimize |= list_cmp == NULL;
    }

    if (cannot_optimize) {
        // lists are definitely different - cannot use internal compare function
        if (list->collection.size == other->collection.size) {
            CxIterator left = list->cl->iterator(list, 0, false);
            CxIterator right = other->cl->iterator(other, 0, false);
            for (size_t i = 0; i < list->collection.size; i++) {
                void *leftValue = cxIteratorCurrent(left);
                void *rightValue = cxIteratorCurrent(right);
                int d = list->collection.cmpfunc(leftValue, rightValue);
                if (d != 0) {
                    return d;
                }
                cxIteratorNext(left);
                cxIteratorNext(right);
            }
            return 0;
        } else {
            return list->collection.size < other->collection.size ? -1 : 1;
        }
    } else {
        // lists are compatible
        return list->cl->compare(list, other);
    }
}

CxIterator cxListMutIteratorAt(
        CxList *list,
        size_t index
) {
    CxIterator it = list->cl->iterator(list, index, false);
    it.base.mutating = true;
    return it;
}

CxIterator cxListMutBackwardsIteratorAt(
        CxList *list,
        size_t index
) {
    CxIterator it = list->cl->iterator(list, index, true);
    it.base.mutating = true;
    return it;
}