/* $OpenBSD: bn_print.c,v 1.33 2022/01/20 10:53:33 inoguchi Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <ctype.h>
#include <limits.h>
#include <stdio.h>

#include <openssl/opensslconf.h>

#include <openssl/bio.h>
#include <openssl/buffer.h>
#include <openssl/err.h>

#include "bn_lcl.h"

static const char Hex[]="0123456789ABCDEF";

/* Must 'free' the returned data */
char *
BN_bn2hex(const BIGNUM *a)
{
        int i, j, v, z = 0;
        char *buf;
        char *p;

        buf = malloc(BN_is_negative(a) + a->top * BN_BYTES * 2 + 2);
        if (buf == NULL) {
                BNerror(ERR_R_MALLOC_FAILURE);
                goto err;
        }
        p = buf;
        if (BN_is_negative(a))
                *p++ = '-';
        if (BN_is_zero(a))
                *p++ = '0';
        for (i = a->top - 1; i >=0; i--) {
                for (j = BN_BITS2 - 8; j >= 0; j -= 8) {
                        /* strip leading zeros */
                        v = ((int)(a->d[i] >> (long)j)) & 0xff;
                        if (z || (v != 0)) {
                                *p++ = Hex[v >> 4];
                                *p++ = Hex[v & 0x0f];
                                z = 1;
                        }
                }
        }
        *p = '\0';

err:
        return (buf);
}

/* Must 'free' the returned data */
char *
BN_bn2dec(const BIGNUM *a)
{
        int i = 0, num, bn_data_num, ok = 0;
        char *buf = NULL;
        char *p;
        BIGNUM *t = NULL;
        BN_ULONG *bn_data = NULL, *lp;

        if (BN_is_zero(a)) {
                buf = malloc(BN_is_negative(a) + 2);
                if (buf == NULL) {
                        BNerror(ERR_R_MALLOC_FAILURE);
                        goto err;
                }
                p = buf;
                if (BN_is_negative(a))
                        *p++ = '-';
                *p++ = '0';
                *p++ = '\0';
                return (buf);
        }

        /* get an upper bound for the length of the decimal integer
         * num <= (BN_num_bits(a) + 1) * log(2)
         *     <= 3 * BN_num_bits(a) * 0.1001 + log(2) + 1     (rounding error)
         *     <= BN_num_bits(a)/10 + BN_num_bits/1000 + 1 + 1
         */
        i = BN_num_bits(a) * 3;
        num = (i / 10 + i / 1000 + 1) + 1;
        bn_data_num = num / BN_DEC_NUM + 1;
        bn_data = reallocarray(NULL, bn_data_num, sizeof(BN_ULONG));
        buf = malloc(num + 3);
        if ((buf == NULL) || (bn_data == NULL)) {
                BNerror(ERR_R_MALLOC_FAILURE);
                goto err;
        }
        if ((t = BN_dup(a)) == NULL)
                goto err;

#define BUF_REMAIN (num+3 - (size_t)(p - buf))
        p = buf;
        lp = bn_data;
        if (BN_is_negative(t))
                *p++ = '-';

        while (!BN_is_zero(t)) {
                if (lp - bn_data >= bn_data_num)
                        goto err;
                *lp = BN_div_word(t, BN_DEC_CONV);
                if (*lp == (BN_ULONG)-1)
                        goto err;
                lp++;
        }
        lp--;
        /* We now have a series of blocks, BN_DEC_NUM chars
         * in length, where the last one needs truncation.
         * The blocks need to be reversed in order. */
        snprintf(p, BUF_REMAIN, BN_DEC_FMT1, *lp);
        while (*p)
                p++;
        while (lp != bn_data) {
                lp--;
                snprintf(p, BUF_REMAIN, BN_DEC_FMT2, *lp);
                while (*p)
                        p++;
        }
        ok = 1;

err:
        free(bn_data);
        BN_free(t);
        if (!ok && buf) {
                free(buf);
                buf = NULL;
        }

        return (buf);
}

int
BN_hex2bn(BIGNUM **bn, const char *a)
{
        BIGNUM *ret = NULL;
        BN_ULONG l = 0;
        int neg = 0, h, m, i,j, k, c;
        int num;

        if ((a == NULL) || (*a == '\0'))
                return (0);

        if (*a == '-') {
                neg = 1;
                a++;
        }

        for (i = 0; i <= (INT_MAX / 4) && isxdigit((unsigned char)a[i]); i++)
                ;
        if (i > INT_MAX / 4)
                goto err;

        num = i + neg;
        if (bn == NULL)
                return (num);

        /* a is the start of the hex digits, and it is 'i' long */
        if (*bn == NULL) {
                if ((ret = BN_new()) == NULL)
                        return (0);
        } else {
                ret = *bn;
                BN_zero(ret);
        }

        /* i is the number of hex digits */
        if (bn_expand(ret, i * 4) == NULL)
                goto err;

        j = i; /* least significant 'hex' */
        m = 0;
        h = 0;
        while (j > 0) {
                m = ((BN_BYTES * 2) <= j) ? (BN_BYTES * 2) : j;
                l = 0;
                for (;;) {
                        c = a[j - m];
                        if ((c >= '0') && (c <= '9'))
                                k = c - '0';
                        else if ((c >= 'a') && (c <= 'f'))
                                k = c - 'a' + 10;
                        else if ((c >= 'A') && (c <= 'F'))
                                k = c - 'A' + 10;
                        else
                                k = 0; /* paranoia */
                        l = (l << 4) | k;

                        if (--m <= 0) {
                                ret->d[h++] = l;
                                break;
                        }
                }
                j -= (BN_BYTES * 2);
        }
        ret->top = h;
        bn_correct_top(ret);
        ret->neg = neg;

        *bn = ret;
        bn_check_top(ret);
        return (num);

err:
        if (*bn == NULL)
                BN_free(ret);
        return (0);
}

int
BN_dec2bn(BIGNUM **bn, const char *a)
{
        BIGNUM *ret = NULL;
        BN_ULONG l = 0;
        int neg = 0, i, j;
        int num;

        if ((a == NULL) || (*a == '\0'))
                return (0);
        if (*a == '-') {
                neg = 1;
                a++;
        }

        for (i = 0; i <= (INT_MAX / 4) && isdigit((unsigned char)a[i]); i++)
                ;
        if (i > INT_MAX / 4)
                goto err;

        num = i + neg;
        if (bn == NULL)
                return (num);

        /* a is the start of the digits, and it is 'i' long.
         * We chop it into BN_DEC_NUM digits at a time */
        if (*bn == NULL) {
                if ((ret = BN_new()) == NULL)
                        return (0);
        } else {
                ret = *bn;
                BN_zero(ret);
        }

        /* i is the number of digits, a bit of an over expand */
        if (bn_expand(ret, i * 4) == NULL)
                goto err;

        j = BN_DEC_NUM - (i % BN_DEC_NUM);
        if (j == BN_DEC_NUM)
                j = 0;
        l = 0;
        while (*a) {
                l *= 10;
                l += *a - '0';
                a++;
                if (++j == BN_DEC_NUM) {
                        if (!BN_mul_word(ret, BN_DEC_CONV))
                                goto err;
                        if (!BN_add_word(ret, l))
                                goto err;
                        l = 0;
                        j = 0;
                }
        }
        ret->neg = neg;

        bn_correct_top(ret);
        *bn = ret;
        bn_check_top(ret);
        return (num);

err:
        if (*bn == NULL)
                BN_free(ret);
        return (0);
}

int
BN_asc2bn(BIGNUM **bn, const char *a)
{
        const char *p = a;
        if (*p == '-')
                p++;

        if (p[0] == '0' && (p[1] == 'X' || p[1] == 'x')) {
                if (!BN_hex2bn(bn, p + 2))
                        return 0;
        } else {
                if (!BN_dec2bn(bn, p))
                        return 0;
        }
        if (*a == '-')
                (*bn)->neg = 1;
        return 1;
}

#ifndef OPENSSL_NO_BIO
int
BN_print_fp(FILE *fp, const BIGNUM *a)
{
        BIO *b;
        int ret;

        if ((b = BIO_new(BIO_s_file())) == NULL)
                return (0);
        BIO_set_fp(b, fp, BIO_NOCLOSE);
        ret = BN_print(b, a);
        BIO_free(b);
        return (ret);
}

int
BN_print(BIO *bp, const BIGNUM *a)
{
        int i, j, v, z = 0;
        int ret = 0;

        if ((a->neg) && (BIO_write(bp, "-", 1) != 1))
                goto end;
        if (BN_is_zero(a) && (BIO_write(bp, "0", 1) != 1))
                goto end;
        for (i = a->top - 1; i >= 0; i--) {
                for (j = BN_BITS2 - 4; j >= 0; j -= 4) {
                        /* strip leading zeros */
                        v = ((int)(a->d[i] >> (long)j)) & 0x0f;
                        if (z || (v != 0)) {
                                if (BIO_write(bp, &(Hex[v]), 1) != 1)
                                        goto end;
                                z = 1;
                        }
                }
        }
        ret = 1;

end:
        return (ret);
}
#endif

char *
BN_options(void)
{
        static int init = 0;
        static char data[16];

        if (!init) {
                init++;
#ifdef BN_LLONG
                snprintf(data,sizeof data, "bn(%d,%d)",
                    (int)sizeof(BN_ULLONG) * 8, (int)sizeof(BN_ULONG) * 8);
#else
                snprintf(data,sizeof data, "bn(%d,%d)",
                    (int)sizeof(BN_ULONG) * 8, (int)sizeof(BN_ULONG) * 8);
#endif
        }
        return (data);
}