43 lines
1.1 KiB
C
43 lines
1.1 KiB
C
#include "amplify_tommath_private.h"
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#ifdef AMPLIFY_BN_MP_TO_UBIN_C
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/* LibTomMath, multiple-precision integer library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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/* Modifications Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. */
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/* store in unsigned [big endian] format */
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amplify_mp_err amplify_mp_to_ubin(const amplify_mp_int *a, unsigned char *buf, size_t maxlen, size_t *written)
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{
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size_t x, count;
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amplify_mp_err err;
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amplify_mp_int t;
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count = amplify_mp_ubin_size(a);
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if (count > maxlen) {
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return AMPLIFY_MP_BUF;
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}
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if ((err = amplify_mp_init_copy(&t, a)) != AMPLIFY_MP_OKAY) {
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return err;
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}
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for (x = count; x --> 0u;) {
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#ifndef AMPLIFY_MP_8BIT
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buf[x] = (unsigned char)(t.dp[0] & 255u);
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#else
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buf[x] = (unsigned char)(t.dp[0] | ((t.dp[1] & 1u) << 7));
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#endif
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if ((err = amplify_mp_div_2d(&t, 8, &t, NULL)) != AMPLIFY_MP_OKAY) {
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goto LBL_ERR;
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}
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}
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if (written != NULL) {
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*written = count;
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}
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LBL_ERR:
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amplify_mp_clear(&t);
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return err;
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}
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#endif
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