/*

 * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <stdio.h>

#include "internal/cryptlib.h"

#include "internal/numbers.h"

#include <openssl/stack.h>

#include <openssl/objects.h>

#include <errno.h>

#include <openssl/e_os2.h>      /* For ossl_inline */

/*

 * The initial number of nodes in the array.

 */

static const int min_nodes = 4;

static const int max_nodes = SIZE_MAX / sizeof(void *) < INT_MAX

                             ? (int)(SIZE_MAX / sizeof(void *))

                             : INT_MAX;

struct stack_st {

    int num;

    const void **data;

    int sorted;

    int num_alloc;

    OPENSSL_sk_compfunc comp;

};

OPENSSL_sk_compfunc OPENSSL_sk_set_cmp_func(OPENSSL_STACK *sk, OPENSSL_sk_compfunc c)

{

    OPENSSL_sk_compfunc old = sk->comp;

    if (sk->comp != c)

        sk->sorted = 0;

    sk->comp = c;

    return old;

}

OPENSSL_STACK *OPENSSL_sk_dup(const OPENSSL_STACK *sk)

{

    OPENSSL_STACK *ret;

    if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {

        CRYPTOerr(CRYPTO_F_OPENSSL_SK_DUP, ERR_R_MALLOC_FAILURE);

        return NULL;

    }

    /* direct structure assignment */

    *ret = *sk;

    if (sk->num == 0) {

        /* postpone |ret->data| allocation */

        ret->data = NULL;

        ret->num_alloc = 0;

        return ret;

    }

    /* duplicate |sk->data| content */

    if ((ret->data = OPENSSL_malloc(sizeof(*ret->data) * sk->num_alloc)) == NULL)

        goto err;

    memcpy(ret->data, sk->data, sizeof(void *) * sk->num);

    return ret;

 err:

    OPENSSL_sk_free(ret);

    return NULL;

}

OPENSSL_STACK *OPENSSL_sk_deep_copy(const OPENSSL_STACK *sk,

                             OPENSSL_sk_copyfunc copy_func,

                             OPENSSL_sk_freefunc free_func)

{

    OPENSSL_STACK *ret;

    int i;

    if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {

        CRYPTOerr(CRYPTO_F_OPENSSL_SK_DEEP_COPY, ERR_R_MALLOC_FAILURE);

        return NULL;

    }

    /* direct structure assignment */

    *ret = *sk;

    if (sk->num == 0) {

        /* postpone |ret| data allocation */

        ret->data = NULL;

        ret->num_alloc = 0;

        return ret;

    }

    ret->num_alloc = sk->num > min_nodes ? sk->num : min_nodes;

    ret->data = OPENSSL_zalloc(sizeof(*ret->data) * ret->num_alloc);

    if (ret->data == NULL) {

        OPENSSL_free(ret);

        return NULL;

    }

    for (i = 0; i < ret->num; ++i) {

        if (sk->data[i] == NULL)

            continue;

        if ((ret->data[i] = copy_func(sk->data[i])) == NULL) {

            while (--i >= 0)

                if (ret->data[i] != NULL)

                    free_func((void *)ret->data[i]);

            OPENSSL_sk_free(ret);

            return NULL;

        }

    }

    return ret;

}

OPENSSL_STACK *OPENSSL_sk_new_null(void)

{

    return OPENSSL_sk_new_reserve(NULL, 0);

}

OPENSSL_STACK *OPENSSL_sk_new(OPENSSL_sk_compfunc c)

{

    return OPENSSL_sk_new_reserve(c, 0);

}

/*

 * Calculate the array growth based on the target size.

 *

 * The growth fraction is a rational number and is defined by a numerator

 * and a denominator.  According to Andrew Koenig in his paper "Why Are

 * Vectors Efficient?" from JOOP 11(5) 1998, this factor should be less

 * than the golden ratio (1.618...).

 *

 * We use 3/2 = 1.5 for simplicity of calculation and overflow checking.

 * Another option 8/5 = 1.6 allows for slightly faster growth, although safe

 * computation is more difficult.

 *

 * The limit to avoid overflow is spot on.  The modulo three correction term

 * ensures that the limit is the largest number than can be expanded by the

 * growth factor without exceeding the hard limit.

 *

 * Do not call it with |current| lower than 2, or it will infinitely loop.

 */

static ossl_inline int compute_growth(int target, int current)

{

    const int limit = (max_nodes / 3) * 2 + (max_nodes % 3 ? 1 : 0);

    while (current < target) {

        /* Check to see if we're at the hard limit */

        if (current >= max_nodes)

            return 0;

        /* Expand the size by a factor of 3/2 if it is within range */

        current = current < limit ? current + current / 2 : max_nodes;

    }

    return current;

}

/* internal STACK storage allocation */

static int sk_reserve(OPENSSL_STACK *st, int n, int exact)

{

    const void **tmpdata;

    int num_alloc;

    /* Check to see the reservation isn't exceeding the hard limit */

    if (n > max_nodes - st->num)

        return 0;

    /* Figure out the new size */

    num_alloc = st->num + n;

    if (num_alloc < min_nodes)

        num_alloc = min_nodes;

    /* If |st->data| allocation was postponed */

    if (st->data == NULL) {

        /*

         * At this point, |st->num_alloc| and |st->num| are 0;

         * so |num_alloc| value is |n| or |min_nodes| if greater than |n|.

         */

        if ((st->data = OPENSSL_zalloc(sizeof(void *) * num_alloc)) == NULL) {

            CRYPTOerr(CRYPTO_F_SK_RESERVE, ERR_R_MALLOC_FAILURE);

            return 0;

        }

        st->num_alloc = num_alloc;

        return 1;

    }

    if (!exact) {

        if (num_alloc <= st->num_alloc)

            return 1;

        num_alloc = compute_growth(num_alloc, st->num_alloc);

        if (num_alloc == 0)

            return 0;

    } else if (num_alloc == st->num_alloc) {

        return 1;

    }

    tmpdata = OPENSSL_realloc((void *)st->data, sizeof(void *) * num_alloc);

    if (tmpdata == NULL)

        return 0;

    st->data = tmpdata;

    st->num_alloc = num_alloc;

    return 1;

}

OPENSSL_STACK *OPENSSL_sk_new_reserve(OPENSSL_sk_compfunc c, int n)

{

    OPENSSL_STACK *st = OPENSSL_zalloc(sizeof(OPENSSL_STACK));

    if (st == NULL)

        return NULL;

    st->comp = c;

    if (n <= 0)

        return st;

    if (!sk_reserve(st, n, 1)) {

        OPENSSL_sk_free(st);

        return NULL;

    }

    return st;

}

int OPENSSL_sk_reserve(OPENSSL_STACK *st, int n)

{

    if (st == NULL)

        return 0;

    if (n < 0)

        return 1;

    return sk_reserve(st, n, 1);

}

int OPENSSL_sk_insert(OPENSSL_STACK *st, const void *data, int loc)

{

    if (st == NULL || st->num == max_nodes)

        return 0;

    if (!sk_reserve(st, 1, 0))

        return 0;

    if ((loc >= st->num) || (loc < 0)) {

        st->data[st->num] = data;

    } else {

        memmove(&st->data[loc + 1], &st->data[loc],

                sizeof(st->data[0]) * (st->num - loc));

        st->data[loc] = data;

    }

    st->num++;

    st->sorted = 0;

    return st->num;

}

static ossl_inline void *internal_delete(OPENSSL_STACK *st, int loc)

{

    const void *ret = st->data[loc];

    if (loc != st->num - 1)

         memmove(&st->data[loc], &st->data[loc + 1],

                 sizeof(st->data[0]) * (st->num - loc - 1));

    st->num--;

    return (void *)ret;

}

void *OPENSSL_sk_delete_ptr(OPENSSL_STACK *st, const void *p)

{

    int i;

    for (i = 0; i < st->num; i++)

        if (st->data[i] == p)

            return internal_delete(st, i);

    return NULL;

}

void *OPENSSL_sk_delete(OPENSSL_STACK *st, int loc)

{

    if (st == NULL || loc < 0 || loc >= st->num)

        return NULL;

    return internal_delete(st, loc);

}

static int internal_find(OPENSSL_STACK *st, const void *data,

                         int ret_val_options)

{

    const void *r;

    int i;

    if (st == NULL || st->num == 0)

        return -1;

    if (st->comp == NULL) {

        for (i = 0; i < st->num; i++)

            if (st->data[i] == data)

                return i;

        return -1;

    }

    if (!st->sorted) {

        if (st->num > 1)

            qsort(st->data, st->num, sizeof(void *), st->comp);

        st->sorted = 1; /* empty or single-element stack is considered sorted */

    }

    if (data == NULL)

        return -1;

    r = OBJ_bsearch_ex_(&data, st->data, st->num, sizeof(void *), st->comp,

                        ret_val_options);

    return r == NULL ? -1 : (int)((const void **)r - st->data);

}

int OPENSSL_sk_find(OPENSSL_STACK *st, const void *data)

{

    return internal_find(st, data, OBJ_BSEARCH_FIRST_VALUE_ON_MATCH);

}

int OPENSSL_sk_find_ex(OPENSSL_STACK *st, const void *data)

{

    return internal_find(st, data, OBJ_BSEARCH_VALUE_ON_NOMATCH);

}

int OPENSSL_sk_push(OPENSSL_STACK *st, const void *data)

{

    if (st == NULL)

        return -1;

    return OPENSSL_sk_insert(st, data, st->num);

}

int OPENSSL_sk_unshift(OPENSSL_STACK *st, const void *data)

{

    return OPENSSL_sk_insert(st, data, 0);

}

void *OPENSSL_sk_shift(OPENSSL_STACK *st)

{

    if (st == NULL || st->num == 0)

        return NULL;

    return internal_delete(st, 0);

}

void *OPENSSL_sk_pop(OPENSSL_STACK *st)

{

    if (st == NULL || st->num == 0)

        return NULL;

    return internal_delete(st, st->num - 1);

}

void OPENSSL_sk_zero(OPENSSL_STACK *st)

{

    if (st == NULL || st->num == 0)

        return;

    memset(st->data, 0, sizeof(*st->data) * st->num);

    st->num = 0;

}

void OPENSSL_sk_pop_free(OPENSSL_STACK *st, OPENSSL_sk_freefunc func)

{

    int i;

    if (st == NULL)

        return;

    for (i = 0; i < st->num; i++)

        if (st->data[i] != NULL)

            func((char *)st->data[i]);

    OPENSSL_sk_free(st);

}

void OPENSSL_sk_free(OPENSSL_STACK *st)

{

    if (st == NULL)

        return;

    OPENSSL_free(st->data);

    OPENSSL_free(st);

}

int OPENSSL_sk_num(const OPENSSL_STACK *st)

{

    return st == NULL ? -1 : st->num;

}

void *OPENSSL_sk_value(const OPENSSL_STACK *st, int i)

{

    if (st == NULL || i < 0 || i >= st->num)

        return NULL;

    return (void *)st->data[i];

}

void *OPENSSL_sk_set(OPENSSL_STACK *st, int i, const void *data)

{

    if (st == NULL || i < 0 || i >= st->num)

        return NULL;

    st->data[i] = data;

    st->sorted = 0;

    return (void *)st->data[i];

}

void OPENSSL_sk_sort(OPENSSL_STACK *st)

{

    if (st != NULL && !st->sorted && st->comp != NULL) {

        if (st->num > 1)

            qsort(st->data, st->num, sizeof(void *), st->comp);

        st->sorted = 1; /* empty or single-element stack is considered sorted */

    }

}

int OPENSSL_sk_is_sorted(const OPENSSL_STACK *st)

{

    return st == NULL ? 1 : st->sorted;

}