238 lines
7.3 KiB
C
238 lines
7.3 KiB
C
/* MD2C.C - RSA Data Security, Inc., MD2 message-digest algorithm
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*/
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/* Copyright (C) 1990-2, RSA Data Security, Inc. Created 1990. All
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rights reserved.
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License to copy and use this software is granted for
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non-commercial Internet Privacy-Enhanced Mail provided that it is
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identified as the "RSA Data Security, Inc. MD2 Message Digest
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Algorithm" in all material mentioning or referencing this software
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or this function.
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RSA Data Security, Inc. makes no representations concerning either
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the merchantability of this software or the suitability of this
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software for any particular purpose. It is provided "as is"
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without express or implied warranty of any kind.
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These notices must be retained in any copies of any part of this
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documentation and/or software.
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*/
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#include "md2.h"
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#define HAVEMEMCOPY 1 /* use ISO C's memcpy and memset */
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static void MD2Transform PROTO_LIST
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((unsigned char [16], unsigned char [16], const unsigned char [16]));
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#ifdef HAVEMEMCOPY
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#include <memory.h>
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#define MD2_memcpy memcpy
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#define MD2_memset memset
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#else
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#ifdef HAVEBCOPY
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#define MD2_memcpy(_a,_b,_c) memcpy((_a), (_b),(_c))
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#define MD2_memset(_a,_b,_c) memset((_a), '\0',(_c))
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#else
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static void MD2_memcpy PROTO_LIST ((POINTER, CONST_POINTER, unsigned int));
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static void MD2_memset PROTO_LIST ((POINTER, int, unsigned int));
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#endif
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#endif
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/* Permutation of 0..255 constructed from the digits of pi. It gives a
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"random" nonlinear byte substitution operation.
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*/
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static unsigned char PI_SUBST[256] = {
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41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,
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19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188,
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76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,
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138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251,
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245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63,
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148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50,
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39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165,
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181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210,
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150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157,
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112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27,
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96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
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85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197,
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234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65,
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129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123,
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8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233,
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203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228,
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166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237,
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31, 26, 219, 153, 141, 51, 159, 17, 131, 20
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};
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static const unsigned char *PADDING[] = {
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(const unsigned char *)"",
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(const unsigned char *)"\001",
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(const unsigned char *)"\002\002",
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(const unsigned char *)"\003\003\003",
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(const unsigned char *)"\004\004\004\004",
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(const unsigned char *)"\005\005\005\005\005",
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(const unsigned char *)"\006\006\006\006\006\006",
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(const unsigned char *)"\007\007\007\007\007\007\007",
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(const unsigned char *)"\010\010\010\010\010\010\010\010",
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(const unsigned char *)"\011\011\011\011\011\011\011\011\011",
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(const unsigned char *)"\012\012\012\012\012\012\012\012\012\012",
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(const unsigned char *)"\013\013\013\013\013\013\013\013\013\013\013",
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(const unsigned char *)"\014\014\014\014\014\014\014\014\014\014\014\014",
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(const unsigned char *)
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"\015\015\015\015\015\015\015\015\015\015\015\015\015",
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(const unsigned char *)
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"\016\016\016\016\016\016\016\016\016\016\016\016\016\016",
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(const unsigned char *)
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"\017\017\017\017\017\017\017\017\017\017\017\017\017\017\017",
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(const unsigned char *)
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"\020\020\020\020\020\020\020\020\020\020\020\020\020\020\020\020"
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};
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/* MD2 initialization. Begins an MD2 operation, writing a new context.
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*/
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void MD2Init (context)
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MD2_CTX *context; /* context */
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{
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context->count = 0;
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MD2_memset ((POINTER)context->state, 0, sizeof (context->state));
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MD2_memset
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((POINTER)context->checksum, 0, sizeof (context->checksum));
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}
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/* MD2 block update operation. Continues an MD2 message-digest
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operation, processing another message block, and updating the
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context.
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*/
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void MD2Update (context, input, inputLen)
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MD2_CTX *context; /* context */
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const unsigned char *input; /* input block */
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unsigned int inputLen; /* length of input block */
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{
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unsigned int i, index, partLen;
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/* Update number of bytes mod 16 */
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index = context->count;
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context->count = (index + inputLen) & 0xf;
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partLen = 16 - index;
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/* Transform as many times as possible.
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*/
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if (inputLen >= partLen) {
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MD2_memcpy
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((POINTER)&context->buffer[index], (CONST_POINTER)input, partLen);
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MD2Transform (context->state, context->checksum, context->buffer);
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for (i = partLen; i + 15 < inputLen; i += 16)
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MD2Transform (context->state, context->checksum, &input[i]);
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index = 0;
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}
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else
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i = 0;
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/* Buffer remaining input */
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MD2_memcpy
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((POINTER)&context->buffer[index], (CONST_POINTER)&input[i],
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inputLen-i);
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}
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/* MD2 finalization. Ends an MD2 message-digest operation, writing the
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message digest and zeroizing the context.
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*/
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void MD2Final (digest, context)
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unsigned char digest[16]; /* message digest */
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MD2_CTX *context; /* context */
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{
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unsigned int index, padLen;
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/* Pad out to multiple of 16.
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*/
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index = context->count;
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padLen = 16 - index;
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MD2Update (context, PADDING[padLen], padLen);
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/* Extend with checksum */
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MD2Update (context, context->checksum, 16);
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/* Store state in digest */
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MD2_memcpy ((POINTER)digest, (POINTER)context->state, 16);
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/* Zeroize sensitive information.
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*/
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MD2_memset ((POINTER)context, 0, sizeof (*context));
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}
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/* MD2 basic transformation. Transforms state and updates checksum
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based on block.
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*/
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static void MD2Transform (state, checksum, block)
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unsigned char state[16];
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unsigned char checksum[16];
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const unsigned char block[16];
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{
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unsigned int i, j, t;
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unsigned char x[48];
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/* Form encryption block from state, block, state ^ block.
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*/
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MD2_memcpy ((POINTER)x, (CONST_POINTER)state, 16);
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MD2_memcpy ((POINTER)x+16, (CONST_POINTER)block, 16);
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for (i = 0; i < 16; i++)
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x[i+32] = state[i] ^ block[i];
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/* Encrypt block (18 rounds).
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*/
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t = 0;
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for (i = 0; i < 18; i++) {
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for (j = 0; j < 48; j++)
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t = x[j] ^= PI_SUBST[t];
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t = (t + i) & 0xff;
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}
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/* Save new state */
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MD2_memcpy ((POINTER)state, (POINTER)x, 16);
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/* Update checksum.
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*/
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t = checksum[15];
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for (i = 0; i < 16; i++)
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t = checksum[i] ^= PI_SUBST[block[i] ^ t];
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/* Zeroize sensitive information.
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*/
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MD2_memset ((POINTER)x, 0, sizeof (x));
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}
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#ifndef HAVEMEMCOPY
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#ifndef HAVEBCOPY
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/* Note: Replace "for loop" with standard memcpy if possible.
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*/
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static void MD2_memcpy (output, input, len)
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POINTER output;
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POINTER input;
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unsigned int len;
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{
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unsigned int i;
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for (i = 0; i < len; i++)
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output[i] = input[i];
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}
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/* Note: Replace "for loop" with standard memset if possible.
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*/
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static void MD2_memset (output, value, len)
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POINTER output;
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int value;
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unsigned int len;
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{
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unsigned int i;
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for (i = 0; i < len; i++)
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((char *)output)[i] = (char)value;
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}
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#endif
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#endif
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