/*
 * Copyright 1995-2016 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>

struct stack_st {
    int num;
    const char **data;
    int sorted;
    size_t num_alloc;
    OPENSSL_sk_compfunc comp;
};

#undef MIN_NODES
#define MIN_NODES       4

#include <errno.h>

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 (sk->num < 0)
        return NULL;

    if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL)
        return NULL;

    /* direct structure assignment */
    *ret = *sk;

    if ((ret->data = OPENSSL_malloc(sizeof(*ret->data) * sk->num_alloc)) == NULL)
        goto err;
    memcpy(ret->data, sk->data, sizeof(char *) * 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 (sk->num < 0)
        return NULL;

    if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL)
        return NULL;

    /* direct structure assignment */
    *ret = *sk;

    ret->num_alloc = sk->num > MIN_NODES ? (size_t)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((OPENSSL_sk_compfunc)NULL);
}

OPENSSL_STACK *OPENSSL_sk_new(OPENSSL_sk_compfunc c)
{
    OPENSSL_STACK *ret;

    if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL)
        goto err;
    if ((ret->data = OPENSSL_zalloc(sizeof(*ret->data) * MIN_NODES)) == NULL)
        goto err;
    ret->comp = c;
    ret->num_alloc = MIN_NODES;
    return (ret);

 err:
    OPENSSL_free(ret);
    return (NULL);
}

int OPENSSL_sk_insert(OPENSSL_STACK *st, const void *data, int loc)
{
    if (st == NULL || st->num < 0 || st->num == INT_MAX) {
        return 0;
    }

    if (st->num_alloc <= (size_t)(st->num + 1)) {
        size_t doub_num_alloc = st->num_alloc * 2;

        /* Overflow checks */
        if (doub_num_alloc < st->num_alloc)
            return 0;

        /* Avoid overflow due to multiplication by sizeof(char *) */
        if (doub_num_alloc > SIZE_MAX / sizeof(char *))
            return 0;

        st->data = OPENSSL_realloc((char *)st->data,
                                   sizeof(char *) * doub_num_alloc);
        if (st->data == NULL) {
            /*
             * Reset these counters to prevent subsequent operations on
             * (now non-existing) heap memory
             */
            st->num_alloc = 0;
            st->num = 0;
            return 0;
        }
        st->num_alloc = doub_num_alloc;
    }
    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;
}

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 OPENSSL_sk_delete(st, i);
    return NULL;
}

void *OPENSSL_sk_delete(OPENSSL_STACK *st, int loc)
{
    const char *ret;

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

    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;
}

static int internal_find(OPENSSL_STACK *st, const void *data,
                         int ret_val_options)
{
    const void *r;
    int i;

    if (st == NULL)
        return -1;

    if (st->comp == NULL) {
        for (i = 0; i < st->num; i++)
            if (st->data[i] == data)
                return (i);
        return (-1);
    }
    OPENSSL_sk_sort(st);
    if (data == NULL)
        return (-1);
    r = OBJ_bsearch_ex_(&data, st->data, st->num, sizeof(void *), st->comp,
                        ret_val_options);
    if (r == NULL)
        return (-1);
    return (int)((const char **)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)
{
    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)
        return (NULL);
    if (st->num <= 0)
        return (NULL);
    return (OPENSSL_sk_delete(st, 0));
}

void *OPENSSL_sk_pop(OPENSSL_STACK *st)
{
    if (st == NULL)
        return (NULL);
    if (st->num <= 0)
        return (NULL);
    return (OPENSSL_sk_delete(st, st->num - 1));
}

void OPENSSL_sk_zero(OPENSSL_STACK *st)
{
    if (st == NULL)
        return;
    if (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)
{
    if (st == NULL)
        return -1;
    return 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;
    return (void *)st->data[i];
}

void OPENSSL_sk_sort(OPENSSL_STACK *st)
{
    if (st && !st->sorted && st->comp != NULL) {
        qsort(st->data, st->num, sizeof(char *), st->comp);
        st->sorted = 1;
    }
}

int OPENSSL_sk_is_sorted(const OPENSSL_STACK *st)
{
    if (st == NULL)
        return 1;
    return st->sorted;
}