mirror of
https://github.com/libretro/scummvm.git
synced 2024-12-22 18:02:05 +00:00
4d3a07b494
* names now comply to our naming conventions * the function computeStreamMD5AsString which computes the MD5 as a hex string now returns it as a Common::String * add doxygen comments svn-id: r54121
298 lines
7.4 KiB
C++
298 lines
7.4 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* $URL$
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* $Id$
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*/
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/*
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* RFC 1321 compliant MD5 implementation,
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* by Christophe Devine <devine(at)cr0.net>
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* this program is licensed under the GPL.
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*/
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#include "common/file.h"
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#include "common/fs.h"
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#include "common/md5.h"
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#include "common/endian.h"
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namespace Common {
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struct md5_context {
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uint32 total[2];
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uint32 state[4];
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uint8 buffer[64];
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};
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static void md5_starts(md5_context *ctx);
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static void md5_update(md5_context *ctx, const uint8 *input, uint32 length);
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static void md5_finish(md5_context *ctx, uint8 digest[16]);
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#define GET_UINT32(n, b, i) (n) = READ_LE_UINT32(b + i)
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#define PUT_UINT32(n, b, i) WRITE_LE_UINT32(b + i, n)
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void md5_starts(md5_context *ctx) {
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ctx->total[0] = 0;
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ctx->total[1] = 0;
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ctx->state[0] = 0x67452301;
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ctx->state[1] = 0xEFCDAB89;
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ctx->state[2] = 0x98BADCFE;
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ctx->state[3] = 0x10325476;
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}
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static void md5_process(md5_context *ctx, const uint8 data[64]) {
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uint32 X[16], A, B, C, D;
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GET_UINT32(X[0], data, 0);
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GET_UINT32(X[1], data, 4);
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GET_UINT32(X[2], data, 8);
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GET_UINT32(X[3], data, 12);
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GET_UINT32(X[4], data, 16);
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GET_UINT32(X[5], data, 20);
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GET_UINT32(X[6], data, 24);
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GET_UINT32(X[7], data, 28);
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GET_UINT32(X[8], data, 32);
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GET_UINT32(X[9], data, 36);
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GET_UINT32(X[10], data, 40);
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GET_UINT32(X[11], data, 44);
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GET_UINT32(X[12], data, 48);
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GET_UINT32(X[13], data, 52);
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GET_UINT32(X[14], data, 56);
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GET_UINT32(X[15], data, 60);
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#define S(x, n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n)))
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#define P(a, b, c, d, k, s, t) \
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{ \
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a += F(b,c,d) + X[k] + t; a = S(a,s) + b; \
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}
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A = ctx->state[0];
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B = ctx->state[1];
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C = ctx->state[2];
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D = ctx->state[3];
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#define F(x, y, z) (z ^ (x & (y ^ z)))
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P(A, B, C, D, 0, 7, 0xD76AA478);
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P(D, A, B, C, 1, 12, 0xE8C7B756);
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P(C, D, A, B, 2, 17, 0x242070DB);
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P(B, C, D, A, 3, 22, 0xC1BDCEEE);
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P(A, B, C, D, 4, 7, 0xF57C0FAF);
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P(D, A, B, C, 5, 12, 0x4787C62A);
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P(C, D, A, B, 6, 17, 0xA8304613);
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P(B, C, D, A, 7, 22, 0xFD469501);
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P(A, B, C, D, 8, 7, 0x698098D8);
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P(D, A, B, C, 9, 12, 0x8B44F7AF);
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P(C, D, A, B, 10, 17, 0xFFFF5BB1);
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P(B, C, D, A, 11, 22, 0x895CD7BE);
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P(A, B, C, D, 12, 7, 0x6B901122);
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P(D, A, B, C, 13, 12, 0xFD987193);
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P(C, D, A, B, 14, 17, 0xA679438E);
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P(B, C, D, A, 15, 22, 0x49B40821);
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#undef F
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#define F(x, y, z) (y ^ (z & (x ^ y)))
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P(A, B, C, D, 1, 5, 0xF61E2562);
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P(D, A, B, C, 6, 9, 0xC040B340);
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P(C, D, A, B, 11, 14, 0x265E5A51);
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P(B, C, D, A, 0, 20, 0xE9B6C7AA);
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P(A, B, C, D, 5, 5, 0xD62F105D);
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P(D, A, B, C, 10, 9, 0x02441453);
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P(C, D, A, B, 15, 14, 0xD8A1E681);
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P(B, C, D, A, 4, 20, 0xE7D3FBC8);
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P(A, B, C, D, 9, 5, 0x21E1CDE6);
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P(D, A, B, C, 14, 9, 0xC33707D6);
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P(C, D, A, B, 3, 14, 0xF4D50D87);
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P(B, C, D, A, 8, 20, 0x455A14ED);
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P(A, B, C, D, 13, 5, 0xA9E3E905);
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P(D, A, B, C, 2, 9, 0xFCEFA3F8);
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P(C, D, A, B, 7, 14, 0x676F02D9);
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P(B, C, D, A, 12, 20, 0x8D2A4C8A);
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#undef F
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#define F(x, y, z) (x ^ y ^ z)
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P(A, B, C, D, 5, 4, 0xFFFA3942);
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P(D, A, B, C, 8, 11, 0x8771F681);
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P(C, D, A, B, 11, 16, 0x6D9D6122);
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P(B, C, D, A, 14, 23, 0xFDE5380C);
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P(A, B, C, D, 1, 4, 0xA4BEEA44);
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P(D, A, B, C, 4, 11, 0x4BDECFA9);
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P(C, D, A, B, 7, 16, 0xF6BB4B60);
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P(B, C, D, A, 10, 23, 0xBEBFBC70);
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P(A, B, C, D, 13, 4, 0x289B7EC6);
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P(D, A, B, C, 0, 11, 0xEAA127FA);
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P(C, D, A, B, 3, 16, 0xD4EF3085);
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P(B, C, D, A, 6, 23, 0x04881D05);
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P(A, B, C, D, 9, 4, 0xD9D4D039);
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P(D, A, B, C, 12, 11, 0xE6DB99E5);
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P(C, D, A, B, 15, 16, 0x1FA27CF8);
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P(B, C, D, A, 2, 23, 0xC4AC5665);
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#undef F
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#define F(x, y, z) (y ^ (x | ~z))
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P(A, B, C, D, 0, 6, 0xF4292244);
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P(D, A, B, C, 7, 10, 0x432AFF97);
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P(C, D, A, B, 14, 15, 0xAB9423A7);
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P(B, C, D, A, 5, 21, 0xFC93A039);
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P(A, B, C, D, 12, 6, 0x655B59C3);
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P(D, A, B, C, 3, 10, 0x8F0CCC92);
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P(C, D, A, B, 10, 15, 0xFFEFF47D);
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P(B, C, D, A, 1, 21, 0x85845DD1);
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P(A, B, C, D, 8, 6, 0x6FA87E4F);
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P(D, A, B, C, 15, 10, 0xFE2CE6E0);
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P(C, D, A, B, 6, 15, 0xA3014314);
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P(B, C, D, A, 13, 21, 0x4E0811A1);
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P(A, B, C, D, 4, 6, 0xF7537E82);
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P(D, A, B, C, 11, 10, 0xBD3AF235);
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P(C, D, A, B, 2, 15, 0x2AD7D2BB);
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P(B, C, D, A, 9, 21, 0xEB86D391);
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#undef F
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ctx->state[0] += A;
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ctx->state[1] += B;
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ctx->state[2] += C;
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ctx->state[3] += D;
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}
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void md5_update(md5_context *ctx, const uint8 *input, uint32 length) {
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uint32 left, fill;
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if (!length)
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return;
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left = ctx->total[0] & 0x3F;
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fill = 64 - left;
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ctx->total[0] += length;
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ctx->total[0] &= 0xFFFFFFFF;
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if (ctx->total[0] < length)
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ctx->total[1]++;
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if (left && length >= fill) {
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memcpy((void *)(ctx->buffer + left), (const void *)input, fill);
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md5_process(ctx, ctx->buffer);
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length -= fill;
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input += fill;
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left = 0;
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}
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while (length >= 64) {
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md5_process(ctx, input);
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length -= 64;
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input += 64;
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}
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if (length) {
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memcpy((void *)(ctx->buffer + left), (const void *)input, length);
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}
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}
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static const uint8 md5_padding[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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void md5_finish(md5_context *ctx, uint8 digest[16]) {
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uint32 last, padn;
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uint32 high, low;
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uint8 msglen[8];
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high = (ctx->total[0] >> 29) | (ctx->total[1] << 3);
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low = (ctx->total[0] << 3);
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PUT_UINT32(low, msglen, 0);
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PUT_UINT32(high, msglen, 4);
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last = ctx->total[0] & 0x3F;
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padn = (last < 56) ? (56 - last) : (120 - last);
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md5_update(ctx, md5_padding, padn);
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md5_update(ctx, msglen, 8);
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PUT_UINT32(ctx->state[0], digest, 0);
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PUT_UINT32(ctx->state[1], digest, 4);
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PUT_UINT32(ctx->state[2], digest, 8);
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PUT_UINT32(ctx->state[3], digest, 12);
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}
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bool computeStreamMD5(ReadStream &stream, uint8 digest[16], uint32 length) {
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#ifdef DISABLE_MD5
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memset(digest, 0, 16);
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#else
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md5_context ctx;
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int i;
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unsigned char buf[1000];
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bool restricted = (length != 0);
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uint32 readlen;
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if (!restricted || sizeof(buf) <= length)
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readlen = sizeof(buf);
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else
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readlen = length;
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md5_starts(&ctx);
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while ((i = stream.read(buf, readlen)) > 0) {
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md5_update(&ctx, buf, i);
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if (restricted) {
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length -= i;
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if (length == 0)
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break;
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if (sizeof(buf) > length)
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readlen = length;
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}
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}
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md5_finish(&ctx, digest);
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#endif
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return true;
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}
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String computeStreamMD5AsString(ReadStream &stream, uint32 length) {
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String md5;
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uint8 digest[16];
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if (computeStreamMD5(stream, digest, length)) {
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for (int i = 0; i < 16; i++) {
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md5 += String::format("%02x", (int)digest[i]);
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}
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}
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return md5;
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}
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} // End of namespace Common
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