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trylink: explain how to modify link and drastically decrease amount of padding (unfortunately, needs hand editing ATM). *: add ALIGN1 / ALIGN2 to global strings and arrays of bytes and shorts size saving: 0.5k
451 lines
12 KiB
C
451 lines
12 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* md5.c - Compute MD5 checksum of strings according to the
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* definition of MD5 in RFC 1321 from April 1992.
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*
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* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.
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*
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* Copyright (C) 1995-1999 Free Software Foundation, Inc.
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* Copyright (C) 2001 Manuel Novoa III
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* Copyright (C) 2003 Glenn L. McGrath
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* Copyright (C) 2003 Erik Andersen
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*
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* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
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*/
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#include "libbb.h"
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#if CONFIG_MD5_SIZE_VS_SPEED < 0 || CONFIG_MD5_SIZE_VS_SPEED > 3
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# define MD5_SIZE_VS_SPEED 2
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#else
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# define MD5_SIZE_VS_SPEED CONFIG_MD5_SIZE_VS_SPEED
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#endif
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/* Initialize structure containing state of computation.
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* (RFC 1321, 3.3: Step 3)
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*/
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void md5_begin(md5_ctx_t *ctx)
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{
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ctx->A = 0x67452301;
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ctx->B = 0xefcdab89;
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ctx->C = 0x98badcfe;
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ctx->D = 0x10325476;
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ctx->total = 0;
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ctx->buflen = 0;
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}
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/* These are the four functions used in the four steps of the MD5 algorithm
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* and defined in the RFC 1321. The first function is a little bit optimized
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* (as found in Colin Plumbs public domain implementation).
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* #define FF(b, c, d) ((b & c) | (~b & d))
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*/
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# define FF(b, c, d) (d ^ (b & (c ^ d)))
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# define FG(b, c, d) FF (d, b, c)
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# define FH(b, c, d) (b ^ c ^ d)
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# define FI(b, c, d) (c ^ (b | ~d))
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/* Hash a single block, 64 bytes long and 4-byte aligned. */
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static void md5_hash_block(const void *buffer, md5_ctx_t *ctx)
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{
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uint32_t correct_words[16];
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const uint32_t *words = buffer;
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# if MD5_SIZE_VS_SPEED > 0
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static const uint32_t C_array[] = {
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/* round 1 */
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0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee,
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0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
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0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
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0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
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/* round 2 */
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0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
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0xd62f105d, 0x2441453, 0xd8a1e681, 0xe7d3fbc8,
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0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
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0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
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/* round 3 */
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0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,
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0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
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0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x4881d05,
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0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
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/* round 4 */
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0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039,
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0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
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0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
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0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391
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};
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static const char P_array[] ALIGN1 = {
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# if MD5_SIZE_VS_SPEED > 1
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, /* 1 */
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# endif /* MD5_SIZE_VS_SPEED > 1 */
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1, 6, 11, 0, 5, 10, 15, 4, 9, 14, 3, 8, 13, 2, 7, 12, /* 2 */
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5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2, /* 3 */
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0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9 /* 4 */
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};
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# if MD5_SIZE_VS_SPEED > 1
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static const char S_array[] ALIGN1 = {
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7, 12, 17, 22,
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5, 9, 14, 20,
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4, 11, 16, 23,
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6, 10, 15, 21
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};
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# endif /* MD5_SIZE_VS_SPEED > 1 */
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# endif
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uint32_t A = ctx->A;
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uint32_t B = ctx->B;
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uint32_t C = ctx->C;
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uint32_t D = ctx->D;
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/* Process all bytes in the buffer with 64 bytes in each round of
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the loop. */
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uint32_t *cwp = correct_words;
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uint32_t A_save = A;
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uint32_t B_save = B;
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uint32_t C_save = C;
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uint32_t D_save = D;
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# if MD5_SIZE_VS_SPEED > 1
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# define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
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const uint32_t *pc;
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const char *pp;
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const char *ps;
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int i;
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uint32_t temp;
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for (i = 0; i < 16; i++) {
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cwp[i] = SWAP_LE32(words[i]);
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}
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words += 16;
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# if MD5_SIZE_VS_SPEED > 2
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pc = C_array;
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pp = P_array;
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ps = S_array - 4;
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for (i = 0; i < 64; i++) {
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if ((i & 0x0f) == 0)
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ps += 4;
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temp = A;
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switch (i >> 4) {
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case 0:
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temp += FF(B, C, D);
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break;
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case 1:
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temp += FG(B, C, D);
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break;
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case 2:
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temp += FH(B, C, D);
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break;
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case 3:
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temp += FI(B, C, D);
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}
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temp += cwp[(int) (*pp++)] + *pc++;
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CYCLIC(temp, ps[i & 3]);
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temp += B;
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A = D;
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D = C;
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C = B;
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B = temp;
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}
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# else
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pc = C_array;
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pp = P_array;
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ps = S_array;
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for (i = 0; i < 16; i++) {
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temp = A + FF(B, C, D) + cwp[(int) (*pp++)] + *pc++;
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CYCLIC(temp, ps[i & 3]);
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temp += B;
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A = D;
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D = C;
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C = B;
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B = temp;
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}
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ps += 4;
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for (i = 0; i < 16; i++) {
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temp = A + FG(B, C, D) + cwp[(int) (*pp++)] + *pc++;
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CYCLIC(temp, ps[i & 3]);
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temp += B;
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A = D;
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D = C;
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C = B;
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B = temp;
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}
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ps += 4;
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for (i = 0; i < 16; i++) {
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temp = A + FH(B, C, D) + cwp[(int) (*pp++)] + *pc++;
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CYCLIC(temp, ps[i & 3]);
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temp += B;
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A = D;
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D = C;
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C = B;
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B = temp;
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}
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ps += 4;
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for (i = 0; i < 16; i++) {
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temp = A + FI(B, C, D) + cwp[(int) (*pp++)] + *pc++;
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CYCLIC(temp, ps[i & 3]);
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temp += B;
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A = D;
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D = C;
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C = B;
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B = temp;
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}
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# endif /* MD5_SIZE_VS_SPEED > 2 */
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# else
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/* First round: using the given function, the context and a constant
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the next context is computed. Because the algorithms processing
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unit is a 32-bit word and it is determined to work on words in
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little endian byte order we perhaps have to change the byte order
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before the computation. To reduce the work for the next steps
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we store the swapped words in the array CORRECT_WORDS. */
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# define OP(a, b, c, d, s, T) \
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do \
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{ \
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a += FF (b, c, d) + (*cwp++ = SWAP_LE32(*words)) + T; \
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++words; \
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CYCLIC (a, s); \
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a += b; \
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} \
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while (0)
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/* It is unfortunate that C does not provide an operator for
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cyclic rotation. Hope the C compiler is smart enough. */
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/* gcc 2.95.4 seems to be --aaronl */
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# define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
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/* Before we start, one word to the strange constants.
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They are defined in RFC 1321 as
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T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
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*/
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# if MD5_SIZE_VS_SPEED == 1
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const uint32_t *pc;
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const char *pp;
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int i;
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# endif /* MD5_SIZE_VS_SPEED */
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/* Round 1. */
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# if MD5_SIZE_VS_SPEED == 1
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pc = C_array;
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for (i = 0; i < 4; i++) {
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OP(A, B, C, D, 7, *pc++);
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OP(D, A, B, C, 12, *pc++);
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OP(C, D, A, B, 17, *pc++);
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OP(B, C, D, A, 22, *pc++);
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}
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# else
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OP(A, B, C, D, 7, 0xd76aa478);
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OP(D, A, B, C, 12, 0xe8c7b756);
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OP(C, D, A, B, 17, 0x242070db);
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OP(B, C, D, A, 22, 0xc1bdceee);
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OP(A, B, C, D, 7, 0xf57c0faf);
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OP(D, A, B, C, 12, 0x4787c62a);
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OP(C, D, A, B, 17, 0xa8304613);
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OP(B, C, D, A, 22, 0xfd469501);
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OP(A, B, C, D, 7, 0x698098d8);
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OP(D, A, B, C, 12, 0x8b44f7af);
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OP(C, D, A, B, 17, 0xffff5bb1);
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OP(B, C, D, A, 22, 0x895cd7be);
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OP(A, B, C, D, 7, 0x6b901122);
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OP(D, A, B, C, 12, 0xfd987193);
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OP(C, D, A, B, 17, 0xa679438e);
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OP(B, C, D, A, 22, 0x49b40821);
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# endif /* MD5_SIZE_VS_SPEED == 1 */
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/* For the second to fourth round we have the possibly swapped words
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in CORRECT_WORDS. Redefine the macro to take an additional first
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argument specifying the function to use. */
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# undef OP
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# define OP(f, a, b, c, d, k, s, T) \
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do \
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{ \
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a += f (b, c, d) + correct_words[k] + T; \
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CYCLIC (a, s); \
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a += b; \
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} \
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while (0)
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/* Round 2. */
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# if MD5_SIZE_VS_SPEED == 1
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pp = P_array;
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for (i = 0; i < 4; i++) {
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OP(FG, A, B, C, D, (int) (*pp++), 5, *pc++);
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OP(FG, D, A, B, C, (int) (*pp++), 9, *pc++);
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OP(FG, C, D, A, B, (int) (*pp++), 14, *pc++);
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OP(FG, B, C, D, A, (int) (*pp++), 20, *pc++);
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}
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# else
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OP(FG, A, B, C, D, 1, 5, 0xf61e2562);
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OP(FG, D, A, B, C, 6, 9, 0xc040b340);
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OP(FG, C, D, A, B, 11, 14, 0x265e5a51);
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OP(FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
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OP(FG, A, B, C, D, 5, 5, 0xd62f105d);
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OP(FG, D, A, B, C, 10, 9, 0x02441453);
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OP(FG, C, D, A, B, 15, 14, 0xd8a1e681);
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OP(FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
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OP(FG, A, B, C, D, 9, 5, 0x21e1cde6);
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OP(FG, D, A, B, C, 14, 9, 0xc33707d6);
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OP(FG, C, D, A, B, 3, 14, 0xf4d50d87);
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OP(FG, B, C, D, A, 8, 20, 0x455a14ed);
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OP(FG, A, B, C, D, 13, 5, 0xa9e3e905);
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OP(FG, D, A, B, C, 2, 9, 0xfcefa3f8);
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OP(FG, C, D, A, B, 7, 14, 0x676f02d9);
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OP(FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
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# endif /* MD5_SIZE_VS_SPEED == 1 */
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/* Round 3. */
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# if MD5_SIZE_VS_SPEED == 1
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for (i = 0; i < 4; i++) {
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OP(FH, A, B, C, D, (int) (*pp++), 4, *pc++);
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OP(FH, D, A, B, C, (int) (*pp++), 11, *pc++);
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OP(FH, C, D, A, B, (int) (*pp++), 16, *pc++);
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OP(FH, B, C, D, A, (int) (*pp++), 23, *pc++);
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}
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# else
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OP(FH, A, B, C, D, 5, 4, 0xfffa3942);
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OP(FH, D, A, B, C, 8, 11, 0x8771f681);
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OP(FH, C, D, A, B, 11, 16, 0x6d9d6122);
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OP(FH, B, C, D, A, 14, 23, 0xfde5380c);
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OP(FH, A, B, C, D, 1, 4, 0xa4beea44);
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OP(FH, D, A, B, C, 4, 11, 0x4bdecfa9);
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OP(FH, C, D, A, B, 7, 16, 0xf6bb4b60);
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OP(FH, B, C, D, A, 10, 23, 0xbebfbc70);
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OP(FH, A, B, C, D, 13, 4, 0x289b7ec6);
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OP(FH, D, A, B, C, 0, 11, 0xeaa127fa);
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OP(FH, C, D, A, B, 3, 16, 0xd4ef3085);
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OP(FH, B, C, D, A, 6, 23, 0x04881d05);
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OP(FH, A, B, C, D, 9, 4, 0xd9d4d039);
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OP(FH, D, A, B, C, 12, 11, 0xe6db99e5);
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OP(FH, C, D, A, B, 15, 16, 0x1fa27cf8);
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OP(FH, B, C, D, A, 2, 23, 0xc4ac5665);
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# endif /* MD5_SIZE_VS_SPEED == 1 */
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/* Round 4. */
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# if MD5_SIZE_VS_SPEED == 1
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for (i = 0; i < 4; i++) {
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OP(FI, A, B, C, D, (int) (*pp++), 6, *pc++);
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OP(FI, D, A, B, C, (int) (*pp++), 10, *pc++);
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OP(FI, C, D, A, B, (int) (*pp++), 15, *pc++);
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OP(FI, B, C, D, A, (int) (*pp++), 21, *pc++);
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}
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# else
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OP(FI, A, B, C, D, 0, 6, 0xf4292244);
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OP(FI, D, A, B, C, 7, 10, 0x432aff97);
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OP(FI, C, D, A, B, 14, 15, 0xab9423a7);
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OP(FI, B, C, D, A, 5, 21, 0xfc93a039);
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OP(FI, A, B, C, D, 12, 6, 0x655b59c3);
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OP(FI, D, A, B, C, 3, 10, 0x8f0ccc92);
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OP(FI, C, D, A, B, 10, 15, 0xffeff47d);
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OP(FI, B, C, D, A, 1, 21, 0x85845dd1);
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OP(FI, A, B, C, D, 8, 6, 0x6fa87e4f);
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OP(FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
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OP(FI, C, D, A, B, 6, 15, 0xa3014314);
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OP(FI, B, C, D, A, 13, 21, 0x4e0811a1);
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OP(FI, A, B, C, D, 4, 6, 0xf7537e82);
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OP(FI, D, A, B, C, 11, 10, 0xbd3af235);
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OP(FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
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OP(FI, B, C, D, A, 9, 21, 0xeb86d391);
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# endif /* MD5_SIZE_VS_SPEED == 1 */
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# endif /* MD5_SIZE_VS_SPEED > 1 */
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/* Add the starting values of the context. */
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A += A_save;
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B += B_save;
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C += C_save;
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D += D_save;
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/* Put checksum in context given as argument. */
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ctx->A = A;
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ctx->B = B;
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ctx->C = C;
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ctx->D = D;
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}
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/* Feed data through a temporary buffer to call md5_hash_aligned_block()
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* with chunks of data that are 4-byte aligned and a multiple of 64 bytes.
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* This function's internal buffer remembers previous data until it has 64
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* bytes worth to pass on. Call md5_end() to flush this buffer. */
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void md5_hash(const void *buffer, size_t len, md5_ctx_t *ctx)
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{
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char *buf=(char *)buffer;
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/* RFC 1321 specifies the possible length of the file up to 2^64 bits,
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* Here we only track the number of bytes. */
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ctx->total += len;
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// Process all input.
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while (len) {
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int i = 64 - ctx->buflen;
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// Copy data into aligned buffer.
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if (i > len) i = len;
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memcpy(ctx->buffer + ctx->buflen, buf, i);
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len -= i;
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ctx->buflen += i;
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buf += i;
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// When buffer fills up, process it.
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if (ctx->buflen == 64) {
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md5_hash_block(ctx->buffer, ctx);
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ctx->buflen = 0;
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}
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}
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}
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/* Process the remaining bytes in the buffer and put result from CTX
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* in first 16 bytes following RESBUF. The result is always in little
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* endian byte order, so that a byte-wise output yields to the wanted
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* ASCII representation of the message digest.
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*
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* IMPORTANT: On some systems it is required that RESBUF is correctly
|
|
* aligned for a 32 bits value.
|
|
*/
|
|
void *md5_end(void *resbuf, md5_ctx_t *ctx)
|
|
{
|
|
char *buf = ctx->buffer;
|
|
int i;
|
|
|
|
/* Pad data to block size. */
|
|
|
|
buf[ctx->buflen++] = 0x80;
|
|
memset(buf + ctx->buflen, 0, 128 - ctx->buflen);
|
|
|
|
/* Put the 64-bit file length in *bits* at the end of the buffer. */
|
|
ctx->total <<= 3;
|
|
if (ctx->buflen > 56) buf += 64;
|
|
for (i = 0; i < 8; i++) buf[56 + i] = ctx->total >> (i*8);
|
|
|
|
/* Process last bytes. */
|
|
if (buf != ctx->buffer) md5_hash_block(ctx->buffer, ctx);
|
|
md5_hash_block(buf, ctx);
|
|
|
|
/* Put result from CTX in first 16 bytes following RESBUF. The result is
|
|
* always in little endian byte order, so that a byte-wise output yields
|
|
* to the wanted ASCII representation of the message digest.
|
|
*
|
|
* IMPORTANT: On some systems it is required that RESBUF is correctly
|
|
* aligned for a 32 bits value.
|
|
*/
|
|
((uint32_t *) resbuf)[0] = SWAP_LE32(ctx->A);
|
|
((uint32_t *) resbuf)[1] = SWAP_LE32(ctx->B);
|
|
((uint32_t *) resbuf)[2] = SWAP_LE32(ctx->C);
|
|
((uint32_t *) resbuf)[3] = SWAP_LE32(ctx->D);
|
|
|
|
return resbuf;
|
|
}
|
|
|