bn_print.c revision 296465 
1/* crypto/bn/bn_print.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to.  The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 *    notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 *    notice, this list of conditions and the following disclaimer in the
30 *    documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 *    must display the following acknowledgement:
33 *    "This product includes cryptographic software written by
34 *     Eric Young (eay@cryptsoft.com)"
35 *    The word 'cryptographic' can be left out if the rouines from the library
36 *    being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 *    the apps directory (application code) you must include an acknowledgement:
39 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed.  i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58
59#include <stdio.h>
60#include <ctype.h>
61#include <limits.h>
62#include "cryptlib.h"
63#include <openssl/buffer.h>
64#include "bn_lcl.h"
65
66static const char Hex[] = "0123456789ABCDEF";
67
68/* Must 'OPENSSL_free' the returned data */
69char *BN_bn2hex(const BIGNUM *a)
70{
71    int i, j, v, z = 0;
72    char *buf;
73    char *p;
74
75    if (a->neg && BN_is_zero(a)) {
76        /* "-0" == 3 bytes including NULL terminator */
77        buf = OPENSSL_malloc(3);
78    } else {
79        buf = OPENSSL_malloc(a->top * BN_BYTES * 2 + 2);
80    }
81    if (buf == NULL) {
82        BNerr(BN_F_BN_BN2HEX, ERR_R_MALLOC_FAILURE);
83        goto err;
84    }
85    p = buf;
86    if (a->neg)
87        *(p++) = '-';
88    if (BN_is_zero(a))
89        *(p++) = '0';
90    for (i = a->top - 1; i >= 0; i--) {
91        for (j = BN_BITS2 - 8; j >= 0; j -= 8) {
92            /* strip leading zeros */
93            v = ((int)(a->d[i] >> (long)j)) & 0xff;
94            if (z || (v != 0)) {
95                *(p++) = Hex[v >> 4];
96                *(p++) = Hex[v & 0x0f];
97                z = 1;
98            }
99        }
100    }
101    *p = '\0';
102 err:
103    return (buf);
104}
105
106/* Must 'OPENSSL_free' the returned data */
107char *BN_bn2dec(const BIGNUM *a)
108{
109    int i = 0, num, ok = 0;
110    char *buf = NULL;
111    char *p;
112    BIGNUM *t = NULL;
113    BN_ULONG *bn_data = NULL, *lp;
114
115    /*-
116     * get an upper bound for the length of the decimal integer
117     * num <= (BN_num_bits(a) + 1) * log(2)
118     *     <= 3 * BN_num_bits(a) * 0.1001 + log(2) + 1     (rounding error)
119     *     <= BN_num_bits(a)/10 + BN_num_bits/1000 + 1 + 1
120     */
121    i = BN_num_bits(a) * 3;
122    num = (i / 10 + i / 1000 + 1) + 1;
123    bn_data =
124        (BN_ULONG *)OPENSSL_malloc((num / BN_DEC_NUM + 1) * sizeof(BN_ULONG));
125    buf = (char *)OPENSSL_malloc(num + 3);
126    if ((buf == NULL) || (bn_data == NULL)) {
127        BNerr(BN_F_BN_BN2DEC, ERR_R_MALLOC_FAILURE);
128        goto err;
129    }
130    if ((t = BN_dup(a)) == NULL)
131        goto err;
132
133#define BUF_REMAIN (num+3 - (size_t)(p - buf))
134    p = buf;
135    lp = bn_data;
136    if (BN_is_zero(t)) {
137        *(p++) = '0';
138        *(p++) = '\0';
139    } else {
140        if (BN_is_negative(t))
141            *p++ = '-';
142
143        i = 0;
144        while (!BN_is_zero(t)) {
145            *lp = BN_div_word(t, BN_DEC_CONV);
146            lp++;
147        }
148        lp--;
149        /*
150         * We now have a series of blocks, BN_DEC_NUM chars in length, where
151         * the last one needs truncation. The blocks need to be reversed in
152         * order.
153         */
154        BIO_snprintf(p, BUF_REMAIN, BN_DEC_FMT1, *lp);
155        while (*p)
156            p++;
157        while (lp != bn_data) {
158            lp--;
159            BIO_snprintf(p, BUF_REMAIN, BN_DEC_FMT2, *lp);
160            while (*p)
161                p++;
162        }
163    }
164    ok = 1;
165 err:
166    if (bn_data != NULL)
167        OPENSSL_free(bn_data);
168    if (t != NULL)
169        BN_free(t);
170    if (!ok && buf) {
171        OPENSSL_free(buf);
172        buf = NULL;
173    }
174
175    return (buf);
176}
177
178int BN_hex2bn(BIGNUM **bn, const char *a)
179{
180    BIGNUM *ret = NULL;
181    BN_ULONG l = 0;
182    int neg = 0, h, m, i, j, k, c;
183    int num;
184
185    if ((a == NULL) || (*a == '\0'))
186        return (0);
187
188    if (*a == '-') {
189        neg = 1;
190        a++;
191    }
192
193    for (i = 0; i <= (INT_MAX/4) && isxdigit((unsigned char)a[i]); i++)
194        continue;
195
196    if (i > INT_MAX/4)
197        goto err;
198
199    num = i + neg;
200    if (bn == NULL)
201        return (num);
202
203    /* a is the start of the hex digits, and it is 'i' long */
204    if (*bn == NULL) {
205        if ((ret = BN_new()) == NULL)
206            return (0);
207    } else {
208        ret = *bn;
209        BN_zero(ret);
210    }
211
212    /* i is the number of hex digits */
213    if (bn_expand(ret, i * 4) == NULL)
214        goto err;
215
216    j = i;                      /* least significant 'hex' */
217    m = 0;
218    h = 0;
219    while (j > 0) {
220        m = ((BN_BYTES * 2) <= j) ? (BN_BYTES * 2) : j;
221        l = 0;
222        for (;;) {
223            c = a[j - m];
224            if ((c >= '0') && (c <= '9'))
225                k = c - '0';
226            else if ((c >= 'a') && (c <= 'f'))
227                k = c - 'a' + 10;
228            else if ((c >= 'A') && (c <= 'F'))
229                k = c - 'A' + 10;
230            else
231                k = 0;          /* paranoia */
232            l = (l << 4) | k;
233
234            if (--m <= 0) {
235                ret->d[h++] = l;
236                break;
237            }
238        }
239        j -= (BN_BYTES * 2);
240    }
241    ret->top = h;
242    bn_correct_top(ret);
243    ret->neg = neg;
244
245    *bn = ret;
246    bn_check_top(ret);
247    return (num);
248 err:
249    if (*bn == NULL)
250        BN_free(ret);
251    return (0);
252}
253
254int BN_dec2bn(BIGNUM **bn, const char *a)
255{
256    BIGNUM *ret = NULL;
257    BN_ULONG l = 0;
258    int neg = 0, i, j;
259    int num;
260
261    if ((a == NULL) || (*a == '\0'))
262        return (0);
263    if (*a == '-') {
264        neg = 1;
265        a++;
266    }
267
268    for (i = 0; i <= (INT_MAX/4) && isdigit((unsigned char)a[i]); i++)
269        continue;
270
271    if (i > INT_MAX/4)
272        goto err;
273
274    num = i + neg;
275    if (bn == NULL)
276        return (num);
277
278    /*
279     * a is the start of the digits, and it is 'i' long. We chop it into
280     * BN_DEC_NUM digits at a time
281     */
282    if (*bn == NULL) {
283        if ((ret = BN_new()) == NULL)
284            return (0);
285    } else {
286        ret = *bn;
287        BN_zero(ret);
288    }
289
290    /* i is the number of digits, a bit of an over expand */
291    if (bn_expand(ret, i * 4) == NULL)
292        goto err;
293
294    j = BN_DEC_NUM - (i % BN_DEC_NUM);
295    if (j == BN_DEC_NUM)
296        j = 0;
297    l = 0;
298    while (*a) {
299        l *= 10;
300        l += *a - '0';
301        a++;
302        if (++j == BN_DEC_NUM) {
303            BN_mul_word(ret, BN_DEC_CONV);
304            BN_add_word(ret, l);
305            l = 0;
306            j = 0;
307        }
308    }
309    ret->neg = neg;
310
311    bn_correct_top(ret);
312    *bn = ret;
313    bn_check_top(ret);
314    return (num);
315 err:
316    if (*bn == NULL)
317        BN_free(ret);
318    return (0);
319}
320
321#ifndef OPENSSL_NO_BIO
322# ifndef OPENSSL_NO_FP_API
323int BN_print_fp(FILE *fp, const BIGNUM *a)
324{
325    BIO *b;
326    int ret;
327
328    if ((b = BIO_new(BIO_s_file())) == NULL)
329        return (0);
330    BIO_set_fp(b, fp, BIO_NOCLOSE);
331    ret = BN_print(b, a);
332    BIO_free(b);
333    return (ret);
334}
335# endif
336
337int BN_print(BIO *bp, const BIGNUM *a)
338{
339    int i, j, v, z = 0;
340    int ret = 0;
341
342    if ((a->neg) && (BIO_write(bp, "-", 1) != 1))
343        goto end;
344    if (BN_is_zero(a) && (BIO_write(bp, "0", 1) != 1))
345        goto end;
346    for (i = a->top - 1; i >= 0; i--) {
347        for (j = BN_BITS2 - 4; j >= 0; j -= 4) {
348            /* strip leading zeros */
349            v = ((int)(a->d[i] >> (long)j)) & 0x0f;
350            if (z || (v != 0)) {
351                if (BIO_write(bp, &(Hex[v]), 1) != 1)
352                    goto end;
353                z = 1;
354            }
355        }
356    }
357    ret = 1;
358 end:
359    return (ret);
360}
361#endif
362