Switch to a leaner MD5 library

1 files changed, 223 insertions, 366 deletions

diff --git a/src/md5.c b/src/md5.c
index 4ee4329..63256a7 100644
--- a/src/md5.c
+++ b/src/md5.c
@@ -1,388 +1,245 @@
 /*
-  Copyright (C) 1999, 2000, 2002 Aladdin Enterprises.  All rights reserved.
-
-  This software is provided 'as-is', without any express or implied
-  warranty.  In no event will the authors be held liable for any damages
-  arising from the use of this software.
-
-  Permission is granted to anyone to use this software for any purpose,
-  including commercial applications, and to alter it and redistribute it
-  freely, subject to the following restrictions:
-
-  1. The origin of this software must not be misrepresented; you must not
-     claim that you wrote the original software. If you use this software
-     in a product, an acknowledgment in the product documentation would be
-     appreciated but is not required.
-  2. Altered source versions must be plainly marked as such, and must not be
-     misrepresented as being the original software.
-  3. This notice may not be removed or altered from any source distribution.
-
-  L. Peter Deutsch
-  ghost@aladdin.com
-
- */
-/* $Id: md5.c,v 1.6 2002/04/13 19:20:28 lpd Exp $ */
-/*
-  Independent implementation of MD5 (RFC 1321).
-
-  This code implements the MD5 Algorithm defined in RFC 1321, whose
-  text is available at
-	http://www.ietf.org/rfc/rfc1321.txt
-  The code is derived from the text of the RFC, including the test suite
-  (section A.5) but excluding the rest of Appendix A.  It does not include
-  any code or documentation that is identified in the RFC as being
-  copyrighted.
-
-  The original and principal author of md5.c is L. Peter Deutsch
-  <ghost@aladdin.com>.  Other authors are noted in the change history
-  that follows (in reverse chronological order):
-
-  2002-04-13 lpd Clarified derivation from RFC 1321; now handles byte order
-	either statically or dynamically; added missing #include <string.h>
-	in library.
-  2002-03-11 lpd Corrected argument list for main(), and added int return
-	type, in test program and T value program.
-  2002-02-21 lpd Added missing #include <stdio.h> in test program.
-  2000-07-03 lpd Patched to eliminate warnings about "constant is
-	unsigned in ANSI C, signed in traditional"; made test program
-	self-checking.
-  1999-11-04 lpd Edited comments slightly for automatic TOC extraction.
-  1999-10-18 lpd Fixed typo in header comment (ansi2knr rather than md5).
-  1999-05-03 lpd Original version.
+ *  md5.c - Compute MD5 checksum of strings according to the
+ *          definition of MD5 in RFC 1321 from April 1992.
+ *
+ *  Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.
+ *
+ *  Copyright (C) 1995-1999 Free Software Foundation, Inc.
+ *  Copyright (C) 2001 Manuel Novoa III
+ *  Copyright (C) 2003 Glenn L. McGrath
+ *  Copyright (C) 2003 Erik Andersen
+ *
+ *  Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  */
 
-#include "md5.h"
-#include <endian.h>
+#include <byteswap.h>
 #include <string.h>
 
-#if __BYTE_ORDER == __LITTLE_ENDIAN
-# define ARCH_IS_BIG_ENDIAN 0
-#elif __BYTE_ORDER == __BIG_ENDIAN
-# define ARCH_IS_BIG_ENDIAN 1
-#endif
+#include "md5.h"
 
-#undef BYTE_ORDER	/* 1 = big-endian, -1 = little-endian, 0 = unknown */
-#ifdef ARCH_IS_BIG_ENDIAN
-#  define BYTE_ORDER (ARCH_IS_BIG_ENDIAN ? 1 : -1)
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define SWAP_LE32(x) (x)
 #else
-#  define BYTE_ORDER 0
+#define SWAP_LE32(x) bswap_32(x)
 #endif
 
-#define T_MASK ((md5_word_t)~0)
-#define T1 /* 0xd76aa478 */ (T_MASK ^ 0x28955b87)
-#define T2 /* 0xe8c7b756 */ (T_MASK ^ 0x173848a9)
-#define T3    0x242070db
-#define T4 /* 0xc1bdceee */ (T_MASK ^ 0x3e423111)
-#define T5 /* 0xf57c0faf */ (T_MASK ^ 0x0a83f050)
-#define T6    0x4787c62a
-#define T7 /* 0xa8304613 */ (T_MASK ^ 0x57cfb9ec)
-#define T8 /* 0xfd469501 */ (T_MASK ^ 0x02b96afe)
-#define T9    0x698098d8
-#define T10 /* 0x8b44f7af */ (T_MASK ^ 0x74bb0850)
-#define T11 /* 0xffff5bb1 */ (T_MASK ^ 0x0000a44e)
-#define T12 /* 0x895cd7be */ (T_MASK ^ 0x76a32841)
-#define T13    0x6b901122
-#define T14 /* 0xfd987193 */ (T_MASK ^ 0x02678e6c)
-#define T15 /* 0xa679438e */ (T_MASK ^ 0x5986bc71)
-#define T16    0x49b40821
-#define T17 /* 0xf61e2562 */ (T_MASK ^ 0x09e1da9d)
-#define T18 /* 0xc040b340 */ (T_MASK ^ 0x3fbf4cbf)
-#define T19    0x265e5a51
-#define T20 /* 0xe9b6c7aa */ (T_MASK ^ 0x16493855)
-#define T21 /* 0xd62f105d */ (T_MASK ^ 0x29d0efa2)
-#define T22    0x02441453
-#define T23 /* 0xd8a1e681 */ (T_MASK ^ 0x275e197e)
-#define T24 /* 0xe7d3fbc8 */ (T_MASK ^ 0x182c0437)
-#define T25    0x21e1cde6
-#define T26 /* 0xc33707d6 */ (T_MASK ^ 0x3cc8f829)
-#define T27 /* 0xf4d50d87 */ (T_MASK ^ 0x0b2af278)
-#define T28    0x455a14ed
-#define T29 /* 0xa9e3e905 */ (T_MASK ^ 0x561c16fa)
-#define T30 /* 0xfcefa3f8 */ (T_MASK ^ 0x03105c07)
-#define T31    0x676f02d9
-#define T32 /* 0x8d2a4c8a */ (T_MASK ^ 0x72d5b375)
-#define T33 /* 0xfffa3942 */ (T_MASK ^ 0x0005c6bd)
-#define T34 /* 0x8771f681 */ (T_MASK ^ 0x788e097e)
-#define T35    0x6d9d6122
-#define T36 /* 0xfde5380c */ (T_MASK ^ 0x021ac7f3)
-#define T37 /* 0xa4beea44 */ (T_MASK ^ 0x5b4115bb)
-#define T38    0x4bdecfa9
-#define T39 /* 0xf6bb4b60 */ (T_MASK ^ 0x0944b49f)
-#define T40 /* 0xbebfbc70 */ (T_MASK ^ 0x4140438f)
-#define T41    0x289b7ec6
-#define T42 /* 0xeaa127fa */ (T_MASK ^ 0x155ed805)
-#define T43 /* 0xd4ef3085 */ (T_MASK ^ 0x2b10cf7a)
-#define T44    0x04881d05
-#define T45 /* 0xd9d4d039 */ (T_MASK ^ 0x262b2fc6)
-#define T46 /* 0xe6db99e5 */ (T_MASK ^ 0x1924661a)
-#define T47    0x1fa27cf8
-#define T48 /* 0xc4ac5665 */ (T_MASK ^ 0x3b53a99a)
-#define T49 /* 0xf4292244 */ (T_MASK ^ 0x0bd6ddbb)
-#define T50    0x432aff97
-#define T51 /* 0xab9423a7 */ (T_MASK ^ 0x546bdc58)
-#define T52 /* 0xfc93a039 */ (T_MASK ^ 0x036c5fc6)
-#define T53    0x655b59c3
-#define T54 /* 0x8f0ccc92 */ (T_MASK ^ 0x70f3336d)
-#define T55 /* 0xffeff47d */ (T_MASK ^ 0x00100b82)
-#define T56 /* 0x85845dd1 */ (T_MASK ^ 0x7a7ba22e)
-#define T57    0x6fa87e4f
-#define T58 /* 0xfe2ce6e0 */ (T_MASK ^ 0x01d3191f)
-#define T59 /* 0xa3014314 */ (T_MASK ^ 0x5cfebceb)
-#define T60    0x4e0811a1
-#define T61 /* 0xf7537e82 */ (T_MASK ^ 0x08ac817d)
-#define T62 /* 0xbd3af235 */ (T_MASK ^ 0x42c50dca)
-#define T63    0x2ad7d2bb
-#define T64 /* 0xeb86d391 */ (T_MASK ^ 0x14792c6e)
-
-
-static void
-md5_process(md5_state_t *pms, const md5_byte_t *data /*[64]*/)
+
+/* Initialize structure containing state of computation.
+ * (RFC 1321, 3.3: Step 3)
+ */
+void md5_begin(md5_ctx_t *ctx)
 {
-    md5_word_t
-	a = pms->abcd[0], b = pms->abcd[1],
-	c = pms->abcd[2], d = pms->abcd[3];
-    md5_word_t t;
-#if BYTE_ORDER > 0
-    /* Define storage only for big-endian CPUs. */
-    md5_word_t X[16];
-#else
-    /* Define storage for little-endian or both types of CPUs. */
-    md5_word_t xbuf[16];
-    const md5_word_t *X;
-#endif
+	ctx->A = 0x67452301;
+	ctx->B = 0xefcdab89;
+	ctx->C = 0x98badcfe;
+	ctx->D = 0x10325476;
 
-    {
-#if BYTE_ORDER == 0
-	/*
-	 * Determine dynamically whether this is a big-endian or
-	 * little-endian machine, since we can use a more efficient
-	 * algorithm on the latter.
-	 */
-	static const int w = 1;
+	ctx->total = 0;
+	ctx->buflen = 0;
+}
 
-	if (*((const md5_byte_t *)&w)) /* dynamic little-endian */
-#endif
-#if BYTE_ORDER <= 0		/* little-endian */
-	{
-	    /*
-	     * On little-endian machines, we can process properly aligned
-	     * data without copying it.
-	     */
-	    if (!((data - (const md5_byte_t *)0) & 3)) {
-		/* data are properly aligned */
-		X = (const md5_word_t *)data;
-	    } else {
-		/* not aligned */
-		memcpy(xbuf, data, 64);
-		X = xbuf;
-	    }
+/* These are the four functions used in the four steps of the MD5 algorithm
+ * and defined in the RFC 1321.  The first function is a little bit optimized
+ * (as found in Colin Plumbs public domain implementation).
+ * #define FF(b, c, d) ((b & c) | (~b & d))
+ */
+# define FF(b, c, d) (d ^ (b & (c ^ d)))
+# define FG(b, c, d) FF (d, b, c)
+# define FH(b, c, d) (b ^ c ^ d)
+# define FI(b, c, d) (c ^ (b | ~d))
+
+/* Hash a single block, 64 bytes long and 4-byte aligned. */
+static void md5_hash_block(const void *buffer, md5_ctx_t *ctx)
+{
+	uint32_t correct_words[16];
+	const uint32_t *words = buffer;
+
+	static const uint32_t C_array[] = {
+		/* round 1 */
+		0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee,
+		0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
+		0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
+		0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
+		/* round 2 */
+		0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
+		0xd62f105d, 0x2441453, 0xd8a1e681, 0xe7d3fbc8,
+		0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
+		0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
+		/* round 3 */
+		0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,
+		0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
+		0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x4881d05,
+		0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
+		/* round 4 */
+		0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039,
+		0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
+		0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
+		0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391
+	};
+
+	static const char P_array[] = {
+		0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,	/* 1 */
+		1, 6, 11, 0, 5, 10, 15, 4, 9, 14, 3, 8, 13, 2, 7, 12,	/* 2 */
+		5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2,	/* 3 */
+		0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9	/* 4 */
+	};
+
+	static const char S_array[] = {
+		7, 12, 17, 22,
+		5, 9, 14, 20,
+		4, 11, 16, 23,
+		6, 10, 15, 21
+	};
+
+	uint32_t A = ctx->A;
+	uint32_t B = ctx->B;
+	uint32_t C = ctx->C;
+	uint32_t D = ctx->D;
+
+	uint32_t *cwp = correct_words;
+
+#  define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
+
+	const uint32_t *pc;
+	const char *pp;
+	const char *ps;
+	int i;
+	uint32_t temp;
+
+	for (i = 0; i < 16; i++) {
+		cwp[i] = SWAP_LE32(words[i]);
 	}
-#endif
-#if BYTE_ORDER == 0
-	else			/* dynamic big-endian */
-#endif
-#if BYTE_ORDER >= 0		/* big-endian */
-	{
-	    /*
-	     * On big-endian machines, we must arrange the bytes in the
-	     * right order.
-	     */
-	    const md5_byte_t *xp = data;
-	    int i;
-
-#  if BYTE_ORDER == 0
-	    X = xbuf;		/* (dynamic only) */
-#  else
-#    define xbuf X		/* (static only) */
-#  endif
-	    for (i = 0; i < 16; ++i, xp += 4)
-		xbuf[i] = xp[0] + (xp[1] << 8) + (xp[2] << 16) + (xp[3] << 24);
+	words += 16;
+
+	pc = C_array;
+	pp = P_array;
+	ps = S_array;
+
+	for (i = 0; i < 16; i++) {
+		temp = A + FF(B, C, D) + cwp[(int) (*pp++)] + *pc++;
+		CYCLIC(temp, ps[i & 3]);
+		temp += B;
+		A = D;
+		D = C;
+		C = B;
+		B = temp;
 	}
-#endif
-    }
-
-#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))
-
-    /* Round 1. */
-    /* Let [abcd k s i] denote the operation
-       a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */
-#define F(x, y, z) (((x) & (y)) | (~(x) & (z)))
-#define SET(a, b, c, d, k, s, Ti)\
-  t = a + F(b,c,d) + X[k] + Ti;\
-  a = ROTATE_LEFT(t, s) + b
-    /* Do the following 16 operations. */
-    SET(a, b, c, d,  0,  7,  T1);
-    SET(d, a, b, c,  1, 12,  T2);
-    SET(c, d, a, b,  2, 17,  T3);
-    SET(b, c, d, a,  3, 22,  T4);
-    SET(a, b, c, d,  4,  7,  T5);
-    SET(d, a, b, c,  5, 12,  T6);
-    SET(c, d, a, b,  6, 17,  T7);
-    SET(b, c, d, a,  7, 22,  T8);
-    SET(a, b, c, d,  8,  7,  T9);
-    SET(d, a, b, c,  9, 12, T10);
-    SET(c, d, a, b, 10, 17, T11);
-    SET(b, c, d, a, 11, 22, T12);
-    SET(a, b, c, d, 12,  7, T13);
-    SET(d, a, b, c, 13, 12, T14);
-    SET(c, d, a, b, 14, 17, T15);
-    SET(b, c, d, a, 15, 22, T16);
-#undef SET
-
-     /* Round 2. */
-     /* Let [abcd k s i] denote the operation
-          a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */
-#define G(x, y, z) (((x) & (z)) | ((y) & ~(z)))
-#define SET(a, b, c, d, k, s, Ti)\
-  t = a + G(b,c,d) + X[k] + Ti;\
-  a = ROTATE_LEFT(t, s) + b
-     /* Do the following 16 operations. */
-    SET(a, b, c, d,  1,  5, T17);
-    SET(d, a, b, c,  6,  9, T18);
-    SET(c, d, a, b, 11, 14, T19);
-    SET(b, c, d, a,  0, 20, T20);
-    SET(a, b, c, d,  5,  5, T21);
-    SET(d, a, b, c, 10,  9, T22);
-    SET(c, d, a, b, 15, 14, T23);
-    SET(b, c, d, a,  4, 20, T24);
-    SET(a, b, c, d,  9,  5, T25);
-    SET(d, a, b, c, 14,  9, T26);
-    SET(c, d, a, b,  3, 14, T27);
-    SET(b, c, d, a,  8, 20, T28);
-    SET(a, b, c, d, 13,  5, T29);
-    SET(d, a, b, c,  2,  9, T30);
-    SET(c, d, a, b,  7, 14, T31);
-    SET(b, c, d, a, 12, 20, T32);
-#undef SET
-
-     /* Round 3. */
-     /* Let [abcd k s t] denote the operation
-          a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */
-#define H(x, y, z) ((x) ^ (y) ^ (z))
-#define SET(a, b, c, d, k, s, Ti)\
-  t = a + H(b,c,d) + X[k] + Ti;\
-  a = ROTATE_LEFT(t, s) + b
-     /* Do the following 16 operations. */
-    SET(a, b, c, d,  5,  4, T33);
-    SET(d, a, b, c,  8, 11, T34);
-    SET(c, d, a, b, 11, 16, T35);
-    SET(b, c, d, a, 14, 23, T36);
-    SET(a, b, c, d,  1,  4, T37);
-    SET(d, a, b, c,  4, 11, T38);
-    SET(c, d, a, b,  7, 16, T39);
-    SET(b, c, d, a, 10, 23, T40);
-    SET(a, b, c, d, 13,  4, T41);
-    SET(d, a, b, c,  0, 11, T42);
-    SET(c, d, a, b,  3, 16, T43);
-    SET(b, c, d, a,  6, 23, T44);
-    SET(a, b, c, d,  9,  4, T45);
-    SET(d, a, b, c, 12, 11, T46);
-    SET(c, d, a, b, 15, 16, T47);
-    SET(b, c, d, a,  2, 23, T48);
-#undef SET
-
-     /* Round 4. */
-     /* Let [abcd k s t] denote the operation
-          a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */
-#define I(x, y, z) ((y) ^ ((x) | ~(z)))
-#define SET(a, b, c, d, k, s, Ti)\
-  t = a + I(b,c,d) + X[k] + Ti;\
-  a = ROTATE_LEFT(t, s) + b
-     /* Do the following 16 operations. */
-    SET(a, b, c, d,  0,  6, T49);
-    SET(d, a, b, c,  7, 10, T50);
-    SET(c, d, a, b, 14, 15, T51);
-    SET(b, c, d, a,  5, 21, T52);
-    SET(a, b, c, d, 12,  6, T53);
-    SET(d, a, b, c,  3, 10, T54);
-    SET(c, d, a, b, 10, 15, T55);
-    SET(b, c, d, a,  1, 21, T56);
-    SET(a, b, c, d,  8,  6, T57);
-    SET(d, a, b, c, 15, 10, T58);
-    SET(c, d, a, b,  6, 15, T59);
-    SET(b, c, d, a, 13, 21, T60);
-    SET(a, b, c, d,  4,  6, T61);
-    SET(d, a, b, c, 11, 10, T62);
-    SET(c, d, a, b,  2, 15, T63);
-    SET(b, c, d, a,  9, 21, T64);
-#undef SET
-
-     /* Then perform the following additions. (That is increment each
-        of the four registers by the value it had before this block
-        was started.) */
-    pms->abcd[0] += a;
-    pms->abcd[1] += b;
-    pms->abcd[2] += c;
-    pms->abcd[3] += d;
-}
 
-void
-md5_init(md5_state_t *pms)
-{
-    pms->count[0] = pms->count[1] = 0;
-    pms->abcd[0] = 0x67452301;
-    pms->abcd[1] = /*0xefcdab89*/ T_MASK ^ 0x10325476;
-    pms->abcd[2] = /*0x98badcfe*/ T_MASK ^ 0x67452301;
-    pms->abcd[3] = 0x10325476;
+	ps += 4;
+	for (i = 0; i < 16; i++) {
+		temp = A + FG(B, C, D) + cwp[(int) (*pp++)] + *pc++;
+		CYCLIC(temp, ps[i & 3]);
+		temp += B;
+		A = D;
+		D = C;
+		C = B;
+		B = temp;
+	}
+	ps += 4;
+	for (i = 0; i < 16; i++) {
+		temp = A + FH(B, C, D) + cwp[(int) (*pp++)] + *pc++;
+		CYCLIC(temp, ps[i & 3]);
+		temp += B;
+		A = D;
+		D = C;
+		C = B;
+		B = temp;
+	}
+	ps += 4;
+	for (i = 0; i < 16; i++) {
+		temp = A + FI(B, C, D) + cwp[(int) (*pp++)] + *pc++;
+		CYCLIC(temp, ps[i & 3]);
+		temp += B;
+		A = D;
+		D = C;
+		C = B;
+		B = temp;
+	}
+
+
+	ctx->A += A;
+	ctx->B += B;
+	ctx->C += C;
+	ctx->D += D;
 }
 
-void
-md5_append(md5_state_t *pms, const md5_byte_t *data, int nbytes)
+/* Feed data through a temporary buffer to call md5_hash_aligned_block()
+ * with chunks of data that are 4-byte aligned and a multiple of 64 bytes.
+ * This function's internal buffer remembers previous data until it has 64
+ * bytes worth to pass on.  Call md5_end() to flush this buffer. */
+
+void md5_hash(const void *buffer, size_t len, md5_ctx_t *ctx)
 {
-    const md5_byte_t *p = data;
-    int left = nbytes;
-    int offset = (pms->count[0] >> 3) & 63;
-    md5_word_t nbits = (md5_word_t)(nbytes << 3);
-
-    if (nbytes <= 0)
-	return;
-
-    /* Update the message length. */
-    pms->count[1] += nbytes >> 29;
-    pms->count[0] += nbits;
-    if (pms->count[0] < nbits)
-	pms->count[1]++;
-
-    /* Process an initial partial block. */
-    if (offset) {
-	int copy = (offset + nbytes > 64 ? 64 - offset : nbytes);
-
-	memcpy(pms->buf + offset, p, copy);
-	if (offset + copy < 64)
-	    return;
-	p += copy;
-	left -= copy;
-	md5_process(pms, pms->buf);
-    }
-
-    /* Process full blocks. */
-    for (; left >= 64; p += 64, left -= 64)
-	md5_process(pms, p);
-
-    /* Process a final partial block. */
-    if (left)
-	memcpy(pms->buf, p, left);
+	char *buf = (char *)buffer;
+
+	/* RFC 1321 specifies the possible length of the file up to 2^64 bits,
+	 * Here we only track the number of bytes.  */
+
+	ctx->total += len;
+
+	// Process all input.
+
+	while (len) {
+		unsigned i = 64 - ctx->buflen;
+
+		// Copy data into aligned buffer.
+
+		if (i > len)
+			i = len;
+		memcpy(ctx->buffer + ctx->buflen, buf, i);
+		len -= i;
+		ctx->buflen += i;
+		buf += i;
+
+		// When buffer fills up, process it.
+
+		if (ctx->buflen == 64) {
+			md5_hash_block(ctx->buffer, ctx);
+			ctx->buflen = 0;
+		}
+	}
 }
 
-void
-md5_finish(md5_state_t *pms, md5_byte_t digest[16])
+/* Process the remaining bytes in the buffer and 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.
+ */
+void md5_end(void *resbuf, md5_ctx_t *ctx)
 {
-    static const md5_byte_t pad[64] = {
-	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
-    };
-    md5_byte_t data[8];
-    int i;
-
-    /* Save the length before padding. */
-    for (i = 0; i < 8; ++i)
-	data[i] = (md5_byte_t)(pms->count[i >> 2] >> ((i & 3) << 3));
-    /* Pad to 56 bytes mod 64. */
-    md5_append(pms, pad, ((55 - (pms->count[0] >> 3)) & 63) + 1);
-    /* Append the length. */
-    md5_append(pms, data, 8);
-    for (i = 0; i < 16; ++i)
-	digest[i] = (md5_byte_t)(pms->abcd[i >> 2] >> ((i & 3) << 3));
+	char *buf = ctx->buffer;
+	int i;
+
+	/* Pad data to block size.  */
+
+	buf[ctx->buflen++] = (char)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);
 }