/*      $OpenBSD: bn_cmp.c,v 1.2 2023/06/21 07:16:08 jsing Exp $ */
/*
 * Copyright (c) 2022 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 <openssl/bn.h>

struct bn_cmp_test {
        const char *a;
        const char *b;
        int cmp;
        int ucmp;
};

struct bn_cmp_test bn_cmp_tests[] = {
        {
                .a = "0",
                .b = "0",
                .cmp = 0,
                .ucmp = 0,
        },
        {
                .a = "-1",
                .b = "0",
                .cmp = -1,
                .ucmp = 1,
        },
        {
                .a = "1ffffffffffffffff",
                .b = "1ffffffffffffffff",
                .cmp = 0,
                .ucmp = 0,
        },
        {
                .a = "1fffffffffffffffe",
                .b = "1ffffffffffffffff",
                .cmp = -1,
                .ucmp = -1,
        },
        {
                .a = "1ffffffffffffffff",
                .b = "1fffffffffffffffe",
                .cmp = 1,
                .ucmp = 1,
        },
        {
                .a = "0",
                .b = "1ffffffffffffffff",
                .cmp = -1,
                .ucmp = -1,
        },
        {
                .a = "1ffffffffffffffff",
                .b = "0",
                .cmp = 1,
                .ucmp = 1,
        },
        {
                .a = "-1ffffffffffffffff",
                .b = "0",
                .cmp = -1,
                .ucmp = 1,
        },
        {
                .a = "1ffffffffffffffff",
                .b = "00000000000000001ffffffffffffffff",
                .cmp = 0,
                .ucmp = 0,
        },
        {
                .a = "-1ffffffffffffffff",
                .b = "-00000000000000001ffffffffffffffff",
                .cmp = 0,
                .ucmp = 0,
        },
        {
                .a = "1ffffffffffffffff",
                .b = "-00000000000000001ffffffffffffffff",
                .cmp = 1,
                .ucmp = 0,
        },
        {
                .a = "-1ffffffffffffffff",
                .b = "00000000000000001ffffffffffffffff",
                .cmp = -1,
                .ucmp = 0,
        },
};

#define N_BN_CMP_TESTS \
    (sizeof(bn_cmp_tests) / sizeof(*bn_cmp_tests))

static int
test_bn_cmp(void)
{
        struct bn_cmp_test *bct;
        BIGNUM *a = NULL, *b = NULL;
        size_t i;
        int ret;
        int failed = 1;

        if ((a = BN_new()) == NULL) {
                fprintf(stderr, "FAIL: failed to create BN\n");
                goto failure;
        }
        if ((b = BN_new()) == NULL) {
                fprintf(stderr, "FAIL: failed to create BN\n");
                goto failure;
        }

        for (i = 0; i < N_BN_CMP_TESTS; i++) {
                bct = &bn_cmp_tests[i];

                if (!BN_hex2bn(&a, bct->a)) {
                        fprintf(stderr, "FAIL: failed to set a from hex\n");
                        goto failure;
                }
                if (!BN_hex2bn(&b, bct->b)) {
                        fprintf(stderr, "FAIL: failed to set b from hex\n");
                        goto failure;
                }

                if ((ret = BN_cmp(a, b)) != bct->cmp) {
                        fprintf(stderr, "FAIL: BN_cmp(%s, %s) = %d, want %d\n",
                            bct->a, bct->b, ret, bct->cmp);
                        goto failure;
                }
                if ((ret = BN_ucmp(a, b)) != bct->ucmp) {
                        fprintf(stderr, "FAIL: BN_ucmp(%s, %s) = %d, want %d\n",
                            bct->a, bct->b, ret, bct->ucmp);
                        goto failure;
                }
        }

        failed = 0;

 failure:
        BN_free(a);
        BN_free(b);

        return failed;
}

static int
test_bn_cmp_null(void)
{
        BIGNUM *a = NULL;
        int ret;
        int failed = 1;

        if ((a = BN_new()) == NULL) {
                fprintf(stderr, "FAIL: failed to create BN\n");
                goto failure;
        }

        /*
         * Comparison to NULL.
         */
        if ((ret = BN_cmp(NULL, NULL)) != 0) {
                fprintf(stderr, "FAIL: BN_cmp(NULL, NULL) == %d, want 0\n", ret);
                goto failure;
        }

        if ((ret = BN_cmp(a, NULL)) != -1) {
                fprintf(stderr, "FAIL: BN_cmp(0, NULL) == %d, want -1\n", ret);
                goto failure;
        }
        if ((ret = BN_cmp(NULL, a)) != 1) {
                fprintf(stderr, "FAIL: BN_cmp(NULL, 0) == %d, want 1\n", ret);
                goto failure;
        }

        if (!BN_set_word(a, 1)) {
                fprintf(stderr, "FAIL: failed to set BN to 1\n");
                goto failure;
        }
        if ((ret = BN_cmp(a, NULL)) != -1) {
                fprintf(stderr, "FAIL: BN_cmp(1, NULL) == %d, want -1\n", ret);
                goto failure;
        }
        if ((ret = BN_cmp(NULL, a)) != 1) {
                fprintf(stderr, "FAIL: BN_cmp(NULL, 1) == %d, want 1\n", ret);
                goto failure;
        }

        BN_set_negative(a, 1);
        if ((ret = BN_cmp(a, NULL)) != -1) {
                fprintf(stderr, "FAIL: BN_cmp(-1, NULL) == %d, want -1\n", ret);
                goto failure;
        }
        if ((ret = BN_cmp(NULL, a)) != 1) {
                fprintf(stderr, "FAIL: BN_cmp(NULL, -1) == %d, want 1\n", ret);
                goto failure;
        }

        failed = 0;

 failure:
        BN_free(a);

        return failed;
}

struct bn_cmp_word_test {
        int a;
        int b;
        int cmp;
        int ucmp;
};

struct bn_cmp_word_test bn_cmp_word_tests[] = {
        {
                .a = -1,
                .b = -1,
                .cmp = 0,
                .ucmp = 0,
        },
        {
                .a = 0,
                .b = 0,
                .cmp = 0,
                .ucmp = 0,
        },
        {
                .a = 1,
                .b = 1,
                .cmp = 0,
                .ucmp = 0,
        },
        {
                .a = 0,
                .b = 1,
                .cmp = -1,
                .ucmp = -1,
        },
        {
                .a = 1,
                .b = 0,
                .cmp = 1,
                .ucmp = 1,
        },
        {
                .a = -1,
                .b = 0,
                .cmp = -1,
                .ucmp = 1,
        },
        {
                .a = 0,
                .b = -1,
                .cmp = 1,
                .ucmp = -1,
        },
        {
                .a = -1,
                .b = 1,
                .cmp = -1,
                .ucmp = 0,
        },
        {
                .a = 1,
                .b = -1,
                .cmp = 1,
                .ucmp = 0,
        },
};

#define N_BN_CMP_WORD_TESTS \
    (sizeof(bn_cmp_word_tests) / sizeof(*bn_cmp_word_tests))

static int
test_bn_cmp_word(void)
{
        struct bn_cmp_word_test *bcwt;
        BIGNUM *a = NULL, *b = NULL;
        BN_ULONG v;
        size_t i;
        int ret;
        int failed = 1;

        if ((a = BN_new()) == NULL) {
                fprintf(stderr, "FAIL: failed to create BN\n");
                goto failure;
        }
        if ((b = BN_new()) == NULL) {
                fprintf(stderr, "FAIL: failed to create BN\n");
                goto failure;
        }

        for (i = 0; i < N_BN_CMP_WORD_TESTS; i++) {
                bcwt = &bn_cmp_word_tests[i];

                if (bcwt->a >= 0) {
                        v = bcwt->a;
                } else {
                        v = 0 - bcwt->a;
                }
                if (!BN_set_word(a, v)) {
                        fprintf(stderr, "FAIL: failed to set a\n");
                        goto failure;
                }
                BN_set_negative(a, (bcwt->a < 0));

                if (bcwt->b >= 0) {
                        v = bcwt->b;
                } else {
                        v = 0 - bcwt->b;
                }
                if (!BN_set_word(b, v)) {
                        fprintf(stderr, "FAIL: failed to set b\n");
                        goto failure;
                }
                BN_set_negative(b, (bcwt->b < 0));

                if ((ret = BN_cmp(a, b)) != bcwt->cmp) {
                        fprintf(stderr, "FAIL: BN_cmp(%d, %d) = %d, want %d\n",
                            bcwt->a, bcwt->b, ret, bcwt->cmp);
                        goto failure;
                }
                if ((ret = BN_ucmp(a, b)) != bcwt->ucmp) {
                        fprintf(stderr, "FAIL: BN_ucmp(%d, %d) = %d, want %d\n",
                            bcwt->a, bcwt->b, ret, bcwt->ucmp);
                        goto failure;
                }
        }

        failed = 0;

 failure:
        BN_free(a);
        BN_free(b);

        return failed;
}

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

        failed |= test_bn_cmp();
        failed |= test_bn_cmp_null();
        failed |= test_bn_cmp_word();

        return failed;
}