/*      $OpenBSD: bn_bits.c,v 1.2 2024/04/15 14:36:16 jsing Exp $ */
/*
 * Copyright (c) 2024 Joel Sing <jsing@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <stdio.h>
#include <string.h>

#include <openssl/bn.h>

static int
test_bn_set_bit(void)
{
        BIGNUM *bn = NULL;
        char *out_str = NULL;
        size_t i;
        int failed = 1;

        if ((bn = BN_new()) == NULL)
                goto failure;

        for (i = 0; i < 128; i++) {
                if (i % 2 == 0) {
                        if (!BN_set_bit(bn, i)) {
                                fprintf(stderr, "FAIL: failed to set bit\n");
                                goto failure;
                        }
                }
                if (BN_is_bit_set(bn, i) != (i % 2 == 0)) {
                        fprintf(stderr, "FAIL: BN_is_bit_set() = %d, want %d\n",
                            BN_is_bit_set(bn, i), (i % 2 == 0));
                        goto failure;
                }
        }

        if ((out_str = BN_bn2hex(bn)) == NULL)
                goto failure;
        if (strcmp(out_str, "55555555555555555555555555555555") != 0) {
                fprintf(stderr, "FAIL: got 0x%s, want 0x%s\n", out_str,
                    "55555555555555555555555555555555");
                goto failure;
        }

        failed = 0;

 failure:
        BN_free(bn);
        free(out_str);

        return failed;
}

static int
test_bn_clear_bit(void)
{
        BIGNUM *bn = NULL;
        char *out_str = NULL;
        size_t i;
        int failed = 1;

        if ((bn = BN_new()) == NULL)
                goto failure;

        for (i = 0; i < 128; i++) {
                if (!BN_set_bit(bn, i)) {
                        fprintf(stderr, "FAIL: failed to set bit\n");
                        goto failure;
                }
                if (i % 2 == 0) {
                        if (!BN_clear_bit(bn, i)) {
                                fprintf(stderr, "FAIL: failed to clear bit\n");
                                goto failure;
                        }
                }
                if (BN_is_bit_set(bn, i) != (i % 2 == 1)) {
                        fprintf(stderr, "FAIL: BN_is_bit_set() = %d, want %d\n",
                            BN_is_bit_set(bn, i), (i % 2 == 1));
                        goto failure;
                }
        }

        if ((out_str = BN_bn2hex(bn)) == NULL)
                goto failure;
        if (strcmp(out_str, "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA") != 0) {
                fprintf(stderr, "FAIL: got 0x%s, want 0x%s\n", out_str,
                    "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA");
                goto failure;
        }

        /* Ensure that clearing results in non-negative zero. */
        if (!BN_one(bn))
                goto failure;
        BN_set_negative(bn, 1);
        if (!BN_clear_bit(bn, 0)) {
                fprintf(stderr, "FAIL: failed to clear bit\n");
                goto failure;
        }
        if (!BN_is_zero(bn)) {
                fprintf(stderr, "FAIL: clear bit did not result in zero\n");
                goto failure;
        }
        if (BN_is_negative(bn)) {
                fprintf(stderr, "FAIL: clear bit resulted in -0\n");
                goto failure;
        }

        failed = 0;

 failure:
        BN_free(bn);
        free(out_str);

        return failed;
}

static int
test_bn_mask_bits(void)
{
        BIGNUM *bn = NULL;
        char *out_str = NULL;
        size_t i;
        int failed = 1;

        if ((bn = BN_new()) == NULL)
                goto failure;

        if (BN_mask_bits(bn, 0)) {
                fprintf(stderr, "FAIL: mask bits should have failed\n");
                goto failure;
        }

        for (i = 0; i < 128; i++) {
                if (!BN_set_bit(bn, i)) {
                        fprintf(stderr, "FAIL: failed to set bit\n");
                        goto failure;
                }
        }

        if ((out_str = BN_bn2hex(bn)) == NULL)
                goto failure;
        if (strcmp(out_str, "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF") != 0) {
                fprintf(stderr, "FAIL: got 0x%s, want 0x%s\n", out_str,
                    "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF");
                goto failure;
        }

        if (!BN_mask_bits(bn, 127)) {
                fprintf(stderr, "FAIL: failed to mask bits\n");
                goto failure;
        }

        free(out_str);
        if ((out_str = BN_bn2hex(bn)) == NULL)
                goto failure;
        if (strcmp(out_str, "7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF") != 0) {
                fprintf(stderr, "FAIL: got 0x%s, want 0x%s\n", out_str,
                    "7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF");
                goto failure;
        }

        if (!BN_mask_bits(bn, 65)) {
                fprintf(stderr, "FAIL: failed to mask bits\n");
                goto failure;
        }

        free(out_str);
        if ((out_str = BN_bn2hex(bn)) == NULL)
                goto failure;
        if (strcmp(out_str, "01FFFFFFFFFFFFFFFF") != 0) {
                fprintf(stderr, "FAIL: got 0x%s, want 0x%s\n", out_str,
                    "01FFFFFFFFFFFFFFFF");
                goto failure;
        }

        /* Ensure that masking results in non-negative zero. */
        if (!BN_one(bn))
                goto failure;
        BN_set_negative(bn, 1);
        if (!BN_mask_bits(bn, 0)) {
                fprintf(stderr, "FAIL: failed to mask bits\n");
                goto failure;
        }
        if (!BN_is_zero(bn)) {
                fprintf(stderr, "FAIL: mask bits did not result in zero\n");
                goto failure;
        }
        if (BN_is_negative(bn)) {
                fprintf(stderr, "FAIL: mask bits resulted in -0\n");
                goto failure;
        }

        failed = 0;

 failure:
        BN_free(bn);
        free(out_str);

        return failed;
}

int
main(int argc, char **argv)
{
        int failed = 0;

        failed |= test_bn_set_bit();
        failed |= test_bn_clear_bit();
        failed |= test_bn_mask_bits();

        return failed;
}