/*
 * Copyright 1995-2023 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (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 "internal/safe_math.h"
#include <openssl/stack.h>
#include <errno.h>
#include <openssl/e_os2.h> /* For ossl_inline */

OSSL_SAFE_MATH_SIGNED(int, int)

/*
 * 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)
 goto err;

 if (sk == NULL) {
 ret->num = 0;
 ret->sorted = 0;
 ret->comp = NULL;
 } else {
 /* direct structure assignment */
 *ret = *sk;
 }

 if (sk == NULL || sk->num == 0) {
 /* postpone |ret->data| allocation */
 ret->data = NULL;
 ret->num_alloc = 0;
 return ret;
 }

 /* duplicate |sk->data| content */
 ret->data = OPENSSL_malloc(sizeof(*ret->data) * sk->num_alloc);
 if (ret->data == 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)
 goto err;

 if (sk == NULL) {
 ret->num = 0;
 ret->sorted = 0;
 ret->comp = NULL;
 } else {
 /* direct structure assignment */
 *ret = *sk;
 }

 if (sk == NULL || 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)
 goto err;

 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]);
 goto err;
 }
 }
 return ret;

 err:
 OPENSSL_sk_free(ret);
 return NULL;
}

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 factor 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...).
 *
 * Considering only the Fibonacci ratios less than the golden ratio, the
 * number of steps from the minimum allocation to integer overflow is:
 * factor decimal growths
 * 3/2 1.5 51
 * 8/5 1.6 45
 * 21/13 1.615... 44
 *
 * All larger factors have the same number of growths.
 *
 * 3/2 and 8/5 have nice power of two shifts, so seem like a good choice.
 */
static ossl_inline int compute_growth(int target, int current)
{
 int err = 0;

 while (current < target) {
 if (current >= max_nodes)
 return 0;

 current = safe_muldiv_int(current, 8, 5, &err);
 if (err != 0)
 return 0;
 if (current >= max_nodes)
 current = 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) {
 ERR_raise(ERR_LIB_CRYPTO, CRYPTO_R_TOO_MANY_RECORDS);
 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)
 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) {
 ERR_raise(ERR_LIB_CRYPTO, CRYPTO_R_TOO_MANY_RECORDS);
 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) {
 ERR_raise(ERR_LIB_CRYPTO, ERR_R_PASSED_NULL_PARAMETER);
 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) {
 ERR_raise(ERR_LIB_CRYPTO, ERR_R_PASSED_NULL_PARAMETER);
 return 0;
 }
 if (st->num == max_nodes) {
 ERR_raise(ERR_LIB_CRYPTO, CRYPTO_R_TOO_MANY_RECORDS);
 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;

 if (st == NULL)
 return NULL;

 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, int *pnum_matched)
{
 const void *r;
 int i, count = 0;
 int *pnum = pnum_matched;

 if (st == NULL || st->num == 0)
 return -1;

 if (pnum == NULL)
 pnum = &count;

 if (st->comp == NULL) {
 for (i = 0; i < st->num; i++)
 if (st->data[i] == data) {
 *pnum = 1;
 return i;
 }
 *pnum = 0;
 return -1;
 }

 if (data == NULL)
 return -1;

 if (!st->sorted) {
 int res = -1;

 for (i = 0; i < st->num; i++)
 if (st->comp(&data, st->data + i) == 0) {
 if (res == -1)
 res = i;
 ++*pnum;
 /* Check if only one result is wanted and exit if so */
 if (pnum_matched == NULL)
 return i;
 }
 if (res == -1)
 *pnum = 0;
 return res;
 }

 if (pnum_matched != NULL)
 ret_val_options |= OSSL_BSEARCH_FIRST_VALUE_ON_MATCH;
 r = ossl_bsearch(&data, st->data, st->num, sizeof(void *), st->comp,
 ret_val_options);

 if (pnum_matched != NULL) {
 *pnum = 0;
 if (r != NULL) {
 const void **p = (const void **)r;

 while (p < st->data + st->num) {
 if (st->comp(&data, p) != 0)
 break;
 ++*pnum;
 ++p;
 }
 }
 }

 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, OSSL_BSEARCH_FIRST_VALUE_ON_MATCH, NULL);
}

int OPENSSL_sk_find_ex(OPENSSL_STACK *st, const void *data)
{
 return internal_find(st, data, OSSL_BSEARCH_VALUE_ON_NOMATCH, NULL);
}

int OPENSSL_sk_find_all(OPENSSL_STACK *st, const void *data, int *pnum)
{
 return internal_find(st, data, OSSL_BSEARCH_FIRST_VALUE_ON_MATCH, pnum);
}

int OPENSSL_sk_push(OPENSSL_STACK *st, const void *data)
{
 if (st == NULL)
 return 0;
 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) {
 ERR_raise(ERR_LIB_CRYPTO, ERR_R_PASSED_NULL_PARAMETER);
 return NULL;
 }
 if (i < 0 || i >= st->num) {
 ERR_raise_data(ERR_LIB_CRYPTO, ERR_R_PASSED_INVALID_ARGUMENT,
 "i=%d", i);
 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;
}