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339 lines
9.5 KiB
C
339 lines
9.5 KiB
C
//
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// MD5 functions for PDFio.
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//
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// Copyright © 2021 by Michael R Sweet.
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// Copyright © 1999 Aladdin Enterprises. All rights reserved.
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//
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// This software is provided 'as-is', without any express or implied
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// warranty. In no event will the authors be held liable for any damages
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// arising from the use of this software.
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//
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// Permission is granted to anyone to use this software for any purpose,
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// including commercial applications, and to alter it and redistribute it
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// freely, subject to the following restrictions:
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//
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// 1. The origin of this software must not be misrepresented; you must not
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// claim that you wrote the original software. If you use this software
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// in a product, an acknowledgment in the product documentation would be
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// appreciated but is not required.
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// 2. Altered source versions must be plainly marked as such, and must not be
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// misrepresented as being the original software.
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// 3. This notice may not be removed or altered from any source distribution.
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//
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// L. Peter Deutsch
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// ghost@aladdin.com
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//
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#include "pdfio-private.h"
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/*
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Independent implementation of MD5 (RFC 1321).
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This code implements the MD5 Algorithm defined in RFC 1321.
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It is derived directly from the text of the RFC and not from the
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reference implementation.
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The original and principal author of md5.c is L. Peter Deutsch
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<ghost@aladdin.com>. Other authors are noted in the change history
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that follows (in reverse chronological order):
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1999-11-04 lpd Edited comments slightly for automatic TOC extraction.
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1999-10-18 lpd Fixed typo in header comment (ansi2knr rather than md5).
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1999-05-03 lpd Original version.
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*/
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#define T1 0xd76aa478
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#define T2 0xe8c7b756
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#define T3 0x242070db
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#define T4 0xc1bdceee
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#define T5 0xf57c0faf
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#define T6 0x4787c62a
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#define T7 0xa8304613
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#define T8 0xfd469501
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#define T9 0x698098d8
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#define T10 0x8b44f7af
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#define T11 0xffff5bb1
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#define T12 0x895cd7be
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#define T13 0x6b901122
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#define T14 0xfd987193
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#define T15 0xa679438e
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#define T16 0x49b40821
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#define T17 0xf61e2562
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#define T18 0xc040b340
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#define T19 0x265e5a51
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#define T20 0xe9b6c7aa
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#define T21 0xd62f105d
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#define T22 0x02441453
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#define T23 0xd8a1e681
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#define T24 0xe7d3fbc8
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#define T25 0x21e1cde6
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#define T26 0xc33707d6
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#define T27 0xf4d50d87
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#define T28 0x455a14ed
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#define T29 0xa9e3e905
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#define T30 0xfcefa3f8
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#define T31 0x676f02d9
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#define T32 0x8d2a4c8a
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#define T33 0xfffa3942
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#define T34 0x8771f681
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#define T35 0x6d9d6122
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#define T36 0xfde5380c
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#define T37 0xa4beea44
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#define T38 0x4bdecfa9
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#define T39 0xf6bb4b60
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#define T40 0xbebfbc70
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#define T41 0x289b7ec6
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#define T42 0xeaa127fa
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#define T43 0xd4ef3085
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#define T44 0x04881d05
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#define T45 0xd9d4d039
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#define T46 0xe6db99e5
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#define T47 0x1fa27cf8
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#define T48 0xc4ac5665
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#define T49 0xf4292244
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#define T50 0x432aff97
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#define T51 0xab9423a7
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#define T52 0xfc93a039
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#define T53 0x655b59c3
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#define T54 0x8f0ccc92
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#define T55 0xffeff47d
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#define T56 0x85845dd1
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#define T57 0x6fa87e4f
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#define T58 0xfe2ce6e0
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#define T59 0xa3014314
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#define T60 0x4e0811a1
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#define T61 0xf7537e82
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#define T62 0xbd3af235
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#define T63 0x2ad7d2bb
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#define T64 0xeb86d391
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static void
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md5_process(_pdfio_md5_t *pms, const uint8_t *data /*[64]*/)
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{
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uint32_t
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a = pms->abcd[0], b = pms->abcd[1],
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c = pms->abcd[2], d = pms->abcd[3];
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uint32_t t;
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#ifndef ARCH_IS_BIG_ENDIAN
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# define ARCH_IS_BIG_ENDIAN 1 /* slower, default implementation */
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#endif
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#if ARCH_IS_BIG_ENDIAN
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/*
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* On big-endian machines, we must arrange the bytes in the right
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* order. (This also works on machines of unknown byte order.)
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*/
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uint32_t X[16];
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const uint8_t *xp = data;
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int i;
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for (i = 0; i < 16; ++i, xp += 4)
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X[i] = xp[0] + (unsigned)(xp[1] << 8) + (unsigned)(xp[2] << 16) + (unsigned)(xp[3] << 24);
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#else /* !ARCH_IS_BIG_ENDIAN */
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/*
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* On little-endian machines, we can process properly aligned data
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* without copying it.
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*/
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uint32_t xbuf[16];
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const uint32_t *X;
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if (!((data - (const uint8_t *)0) & 3)) {
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/* data are properly aligned */
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X = (const uint32_t *)data;
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} else {
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/* not aligned */
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memcpy(xbuf, data, 64);
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X = xbuf;
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}
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#endif
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#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))
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/* Round 1. */
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/* Let [abcd k s i] denote the operation
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a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */
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#define F(x, y, z) (((x) & (y)) | (~(x) & (z)))
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#define SET(a, b, c, d, k, s, Ti)\
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t = a + F(b,c,d) + X[k] + Ti;\
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a = ROTATE_LEFT(t, s) + b
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/* Do the following 16 operations. */
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SET(a, b, c, d, 0, 7, T1);
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SET(d, a, b, c, 1, 12, T2);
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SET(c, d, a, b, 2, 17, T3);
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SET(b, c, d, a, 3, 22, T4);
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SET(a, b, c, d, 4, 7, T5);
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SET(d, a, b, c, 5, 12, T6);
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SET(c, d, a, b, 6, 17, T7);
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SET(b, c, d, a, 7, 22, T8);
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SET(a, b, c, d, 8, 7, T9);
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SET(d, a, b, c, 9, 12, T10);
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SET(c, d, a, b, 10, 17, T11);
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SET(b, c, d, a, 11, 22, T12);
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SET(a, b, c, d, 12, 7, T13);
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SET(d, a, b, c, 13, 12, T14);
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SET(c, d, a, b, 14, 17, T15);
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SET(b, c, d, a, 15, 22, T16);
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#undef SET
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/* Round 2. */
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/* Let [abcd k s i] denote the operation
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a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */
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#define G(x, y, z) (((x) & (z)) | ((y) & ~(z)))
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#define SET(a, b, c, d, k, s, Ti)\
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t = a + G(b,c,d) + X[k] + Ti;\
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a = ROTATE_LEFT(t, s) + b
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/* Do the following 16 operations. */
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SET(a, b, c, d, 1, 5, T17);
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SET(d, a, b, c, 6, 9, T18);
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SET(c, d, a, b, 11, 14, T19);
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SET(b, c, d, a, 0, 20, T20);
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SET(a, b, c, d, 5, 5, T21);
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SET(d, a, b, c, 10, 9, T22);
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SET(c, d, a, b, 15, 14, T23);
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SET(b, c, d, a, 4, 20, T24);
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SET(a, b, c, d, 9, 5, T25);
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SET(d, a, b, c, 14, 9, T26);
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SET(c, d, a, b, 3, 14, T27);
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SET(b, c, d, a, 8, 20, T28);
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SET(a, b, c, d, 13, 5, T29);
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SET(d, a, b, c, 2, 9, T30);
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SET(c, d, a, b, 7, 14, T31);
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SET(b, c, d, a, 12, 20, T32);
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#undef SET
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/* Round 3. */
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/* Let [abcd k s t] denote the operation
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a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */
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#define H(x, y, z) ((x) ^ (y) ^ (z))
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#define SET(a, b, c, d, k, s, Ti)\
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t = a + H(b,c,d) + X[k] + Ti;\
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a = ROTATE_LEFT(t, s) + b
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/* Do the following 16 operations. */
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SET(a, b, c, d, 5, 4, T33);
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SET(d, a, b, c, 8, 11, T34);
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SET(c, d, a, b, 11, 16, T35);
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SET(b, c, d, a, 14, 23, T36);
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SET(a, b, c, d, 1, 4, T37);
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SET(d, a, b, c, 4, 11, T38);
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SET(c, d, a, b, 7, 16, T39);
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SET(b, c, d, a, 10, 23, T40);
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SET(a, b, c, d, 13, 4, T41);
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SET(d, a, b, c, 0, 11, T42);
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SET(c, d, a, b, 3, 16, T43);
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SET(b, c, d, a, 6, 23, T44);
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SET(a, b, c, d, 9, 4, T45);
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SET(d, a, b, c, 12, 11, T46);
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SET(c, d, a, b, 15, 16, T47);
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SET(b, c, d, a, 2, 23, T48);
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#undef SET
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/* Round 4. */
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/* Let [abcd k s t] denote the operation
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a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */
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#define I(x, y, z) ((y) ^ ((x) | ~(z)))
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#define SET(a, b, c, d, k, s, Ti)\
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t = a + I(b,c,d) + X[k] + Ti;\
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a = ROTATE_LEFT(t, s) + b
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/* Do the following 16 operations. */
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SET(a, b, c, d, 0, 6, T49);
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SET(d, a, b, c, 7, 10, T50);
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SET(c, d, a, b, 14, 15, T51);
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SET(b, c, d, a, 5, 21, T52);
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SET(a, b, c, d, 12, 6, T53);
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SET(d, a, b, c, 3, 10, T54);
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SET(c, d, a, b, 10, 15, T55);
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SET(b, c, d, a, 1, 21, T56);
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SET(a, b, c, d, 8, 6, T57);
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SET(d, a, b, c, 15, 10, T58);
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SET(c, d, a, b, 6, 15, T59);
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SET(b, c, d, a, 13, 21, T60);
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SET(a, b, c, d, 4, 6, T61);
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SET(d, a, b, c, 11, 10, T62);
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SET(c, d, a, b, 2, 15, T63);
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SET(b, c, d, a, 9, 21, T64);
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#undef SET
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/* Then perform the following additions. (That is increment each
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of the four registers by the value it had before this block
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was started.) */
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pms->abcd[0] += a;
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pms->abcd[1] += b;
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pms->abcd[2] += c;
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pms->abcd[3] += d;
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}
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void
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_pdfioCryptoMD5Init(_pdfio_md5_t *pms)
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{
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pms->count[0] = pms->count[1] = 0;
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pms->abcd[0] = 0x67452301;
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pms->abcd[1] = 0xefcdab89;
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pms->abcd[2] = 0x98badcfe;
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pms->abcd[3] = 0x10325476;
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}
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void
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_pdfioCryptoMD5Append(_pdfio_md5_t *pms, const uint8_t *data, size_t nbytes)
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{
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const uint8_t *p = data;
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size_t left = nbytes;
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int offset = (pms->count[0] >> 3) & 63;
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uint32_t nbits = (uint32_t)(nbytes << 3);
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if (nbytes == 0)
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return;
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/* Update the message length. */
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pms->count[1] += (unsigned)(nbytes >> 29);
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pms->count[0] += nbits;
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if (pms->count[0] < nbits)
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pms->count[1]++;
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/* Process an initial partial block. */
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if (offset) {
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int copy = (offset + nbytes > 64 ? 64 - offset : nbytes);
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memcpy(pms->buf + offset, p, copy);
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if (offset + copy < 64)
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return;
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p += copy;
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left -= copy;
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md5_process(pms, pms->buf);
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}
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/* Process full blocks. */
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for (; left >= 64; p += 64, left -= 64)
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md5_process(pms, p);
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/* Process a final partial block. */
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if (left)
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memcpy(pms->buf, p, left);
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}
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void
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_pdfioCryptoMD5Finish(_pdfio_md5_t *pms, uint8_t digest[16])
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{
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static const uint8_t pad[64] = {
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0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
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};
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uint8_t data[8];
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int i;
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/* Save the length before padding. */
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for (i = 0; i < 8; ++i)
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data[i] = (uint8_t)(pms->count[i >> 2] >> ((i & 3) << 3));
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/* Pad to 56 bytes mod 64. */
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_pdfioCryptoMD5Append(pms, pad, ((55 - (pms->count[0] >> 3)) & 63) + 1);
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/* Append the length. */
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_pdfioCryptoMD5Append(pms, data, 8);
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for (i = 0; i < 16; ++i)
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digest[i] = (uint8_t)(pms->abcd[i >> 2] >> ((i & 3) << 3));
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}
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