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+/* md5.c - Functions to compute MD5 message digest of files or memory blocks
+ according to the definition of MD5 in RFC 1321 from April 1992.
+ Copyright (C) 1995, 1996, 1997, 1999 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <sys/types.h>
+
+#if STDC_HEADERS || defined _LIBC
+# include <stdlib.h>
+# include <string.h>
+#else
+# ifndef HAVE_MEMCPY
+# define memcpy(d, s, n) bcopy ((s), (d), (n))
+# endif
+#endif
+
+#include "md5.h"
+
+#ifdef _LIBC
+# include <endian.h>
+# if __BYTE_ORDER == __BIG_ENDIAN
+# define WORDS_BIGENDIAN 1
+# endif
+/* We need to keep the namespace clean so define the MD5 function
+ protected using leading __ . */
+# define md5_init_ctx __md5_init_ctx
+# define md5_process_block __md5_process_block
+# define md5_process_bytes __md5_process_bytes
+# define md5_finish_ctx __md5_finish_ctx
+# define md5_read_ctx __md5_read_ctx
+# define md5_stream __md5_stream
+# define md5_buffer __md5_buffer
+#endif
+
+#ifdef WORDS_BIGENDIAN
+# define SWAP(n) \
+ (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
+#else
+# define SWAP(n) (n)
+#endif
+
+
+/* This array contains the bytes used to pad the buffer to the next
+ 64-byte boundary. (RFC 1321, 3.1: Step 1) */
+static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
+
+
+/* Initialize structure containing state of computation.
+ (RFC 1321, 3.3: Step 3) */
+void
+md5_init_ctx (ctx)
+ struct md5_ctx *ctx;
+{
+ ctx->A = 0x67452301;
+ ctx->B = 0xefcdab89;
+ ctx->C = 0x98badcfe;
+ ctx->D = 0x10325476;
+
+ ctx->total[0] = ctx->total[1] = 0;
+ ctx->buflen = 0;
+}
+
+/* Put result from CTX in first 16 bytes following RESBUF. The result
+ must be in little endian byte order.
+
+ IMPORTANT: On some systems it is required that RESBUF is correctly
+ aligned for a 32 bits value. */
+void *
+md5_read_ctx (ctx, resbuf)
+ const struct md5_ctx *ctx;
+ void *resbuf;
+{
+ ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A);
+ ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B);
+ ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C);
+ ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D);
+
+ return resbuf;
+}
+
+/* Process the remaining bytes in the internal buffer and the usual
+ prolog according to the standard and write the result to RESBUF.
+
+ IMPORTANT: On some systems it is required that RESBUF is correctly
+ aligned for a 32 bits value. */
+void *
+md5_finish_ctx (ctx, resbuf)
+ struct md5_ctx *ctx;
+ void *resbuf;
+{
+ /* Take yet unprocessed bytes into account. */
+ md5_uint32 bytes = ctx->buflen;
+ size_t pad;
+
+ /* Now count remaining bytes. */
+ ctx->total[0] += bytes;
+ if (ctx->total[0] < bytes)
+ ++ctx->total[1];
+
+ pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
+ memcpy (&ctx->buffer[bytes], fillbuf, pad);
+
+ /* Put the 64-bit file length in *bits* at the end of the buffer. */
+ *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
+ *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) |
+ (ctx->total[0] >> 29));
+
+ /* Process last bytes. */
+ md5_process_block (ctx->buffer, bytes + pad + 8, ctx);
+
+ return md5_read_ctx (ctx, resbuf);
+}
+
+/* Compute MD5 message digest for bytes read from STREAM. The
+ resulting message digest number will be written into the 16 bytes
+ beginning at RESBLOCK. */
+int
+md5_stream (stream, resblock)
+ FILE *stream;
+ void *resblock;
+{
+ /* Important: BLOCKSIZE must be a multiple of 64. */
+#define BLOCKSIZE 4096
+ struct md5_ctx ctx;
+ char buffer[BLOCKSIZE + 72];
+ size_t sum;
+
+ /* Initialize the computation context. */
+ md5_init_ctx (&ctx);
+
+ /* Iterate over full file contents. */
+ while (1)
+ {
+ /* We read the file in blocks of BLOCKSIZE bytes. One call of the
+ computation function processes the whole buffer so that with the
+ next round of the loop another block can be read. */
+ size_t n;
+ sum = 0;
+
+ /* Read block. Take care for partial reads. */
+ do
+ {
+ n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
+
+ sum += n;
+ }
+ while (sum < BLOCKSIZE && n != 0);
+ if (n == 0 && ferror (stream))
+ return 1;
+
+ /* If end of file is reached, end the loop. */
+ if (n == 0)
+ break;
+
+ /* Process buffer with BLOCKSIZE bytes. Note that
+ BLOCKSIZE % 64 == 0
+ */
+ md5_process_block (buffer, BLOCKSIZE, &ctx);
+ }
+
+ /* Add the last bytes if necessary. */
+ if (sum > 0)
+ md5_process_bytes (buffer, sum, &ctx);
+
+ /* Construct result in desired memory. */
+ md5_finish_ctx (&ctx, resblock);
+ return 0;
+}
+
+/* Compute MD5 message digest for LEN bytes beginning at BUFFER. 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. */
+void *
+md5_buffer (buffer, len, resblock)
+ const char *buffer;
+ size_t len;
+ void *resblock;
+{
+ struct md5_ctx ctx;
+
+ /* Initialize the computation context. */
+ md5_init_ctx (&ctx);
+
+ /* Process whole buffer but last len % 64 bytes. */
+ md5_process_bytes (buffer, len, &ctx);
+
+ /* Put result in desired memory area. */
+ return md5_finish_ctx (&ctx, resblock);
+}
+
+
+void
+md5_process_bytes (buffer, len, ctx)
+ const void *buffer;
+ size_t len;
+ struct md5_ctx *ctx;
+{
+ /* When we already have some bits in our internal buffer concatenate
+ both inputs first. */
+ if (ctx->buflen != 0)
+ {
+ size_t left_over = ctx->buflen;
+ size_t add = 128 - left_over > len ? len : 128 - left_over;
+
+ memcpy (&ctx->buffer[left_over], buffer, add);
+ ctx->buflen += add;
+
+ if (left_over + add > 64)
+ {
+ md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx);
+ /* The regions in the following copy operation cannot overlap. */
+ memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
+ (left_over + add) & 63);
+ ctx->buflen = (left_over + add) & 63;
+ }
+
+ buffer = (const char *) buffer + add;
+ len -= add;
+ }
+
+ /* Process available complete blocks. */
+ if (len > 64)
+ {
+ md5_process_block (buffer, len & ~63, ctx);
+ buffer = (const char *) buffer + (len & ~63);
+ len &= 63;
+ }
+
+ /* Move remaining bytes in internal buffer. */
+ if (len > 0)
+ {
+ memcpy (ctx->buffer, buffer, len);
+ ctx->buflen = len;
+ }
+}
+
+
+/* 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))
+
+/* Process LEN bytes of BUFFER, accumulating context into CTX.
+ It is assumed that LEN % 64 == 0. */
+
+void
+md5_process_block (buffer, len, ctx)
+ const void *buffer;
+ size_t len;
+ struct md5_ctx *ctx;
+{
+ md5_uint32 correct_words[16];
+ const md5_uint32 *words = buffer;
+ size_t nwords = len / sizeof (md5_uint32);
+ const md5_uint32 *endp = words + nwords;
+ md5_uint32 A = ctx->A;
+ md5_uint32 B = ctx->B;
+ md5_uint32 C = ctx->C;
+ md5_uint32 D = ctx->D;
+
+ /* First increment the byte count. RFC 1321 specifies the possible
+ length of the file up to 2^64 bits. Here we only compute the
+ number of bytes. Do a double word increment. */
+ ctx->total[0] += len;
+ if (ctx->total[0] < len)
+ ++ctx->total[1];
+
+ /* Process all bytes in the buffer with 64 bytes in each round of
+ the loop. */
+ while (words < endp)
+ {
+ md5_uint32 *cwp = correct_words;
+ md5_uint32 A_save = A;
+ md5_uint32 B_save = B;
+ md5_uint32 C_save = C;
+ md5_uint32 D_save = D;
+
+ /* First round: using the given function, the context and a constant
+ the next context is computed. Because the algorithms processing
+ unit is a 32-bit word and it is determined to work on words in
+ little endian byte order we perhaps have to change the byte order
+ before the computation. To reduce the work for the next steps
+ we store the swapped words in the array CORRECT_WORDS. */
+
+#define OP(a, b, c, d, s, T) \
+ do \
+ { \
+ a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \
+ ++words; \
+ CYCLIC (a, s); \
+ a += b; \
+ } \
+ while (0)
+
+ /* It is unfortunate that C does not provide an operator for
+ cyclic rotation. Hope the C compiler is smart enough. */
+#define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
+
+ /* Before we start, one word to the strange constants.
+ They are defined in RFC 1321 as
+
+ T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
+ */
+
+ /* Round 1. */
+ OP (A, B, C, D, 7, 0xd76aa478);
+ OP (D, A, B, C, 12, 0xe8c7b756);
+ OP (C, D, A, B, 17, 0x242070db);
+ OP (B, C, D, A, 22, 0xc1bdceee);
+ OP (A, B, C, D, 7, 0xf57c0faf);
+ OP (D, A, B, C, 12, 0x4787c62a);
+ OP (C, D, A, B, 17, 0xa8304613);
+ OP (B, C, D, A, 22, 0xfd469501);
+ OP (A, B, C, D, 7, 0x698098d8);
+ OP (D, A, B, C, 12, 0x8b44f7af);
+ OP (C, D, A, B, 17, 0xffff5bb1);
+ OP (B, C, D, A, 22, 0x895cd7be);
+ OP (A, B, C, D, 7, 0x6b901122);
+ OP (D, A, B, C, 12, 0xfd987193);
+ OP (C, D, A, B, 17, 0xa679438e);
+ OP (B, C, D, A, 22, 0x49b40821);
+
+ /* For the second to fourth round we have the possibly swapped words
+ in CORRECT_WORDS. Redefine the macro to take an additional first
+ argument specifying the function to use. */
+#undef OP
+#define OP(f, a, b, c, d, k, s, T) \
+ do \
+ { \
+ a += f (b, c, d) + correct_words[k] + T; \
+ CYCLIC (a, s); \
+ a += b; \
+ } \
+ while (0)
+
+ /* Round 2. */
+ OP (FG, A, B, C, D, 1, 5, 0xf61e2562);
+ OP (FG, D, A, B, C, 6, 9, 0xc040b340);
+ OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
+ OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
+ OP (FG, A, B, C, D, 5, 5, 0xd62f105d);
+ OP (FG, D, A, B, C, 10, 9, 0x02441453);
+ OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
+ OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
+ OP (FG, A, B, C, D, 9, 5, 0x21e1cde6);
+ OP (FG, D, A, B, C, 14, 9, 0xc33707d6);
+ OP (FG, C, D, A, B, 3, 14, 0xf4d50d87);
+ OP (FG, B, C, D, A, 8, 20, 0x455a14ed);
+ OP (FG, A, B, C, D, 13, 5, 0xa9e3e905);
+ OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8);
+ OP (FG, C, D, A, B, 7, 14, 0x676f02d9);
+ OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
+
+ /* Round 3. */
+ OP (FH, A, B, C, D, 5, 4, 0xfffa3942);
+ OP (FH, D, A, B, C, 8, 11, 0x8771f681);
+ OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
+ OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
+ OP (FH, A, B, C, D, 1, 4, 0xa4beea44);
+ OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9);
+ OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60);
+ OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
+ OP (FH, A, B, C, D, 13, 4, 0x289b7ec6);
+ OP (FH, D, A, B, C, 0, 11, 0xeaa127fa);
+ OP (FH, C, D, A, B, 3, 16, 0xd4ef3085);
+ OP (FH, B, C, D, A, 6, 23, 0x04881d05);
+ OP (FH, A, B, C, D, 9, 4, 0xd9d4d039);
+ OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
+ OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
+ OP (FH, B, C, D, A, 2, 23, 0xc4ac5665);
+
+ /* Round 4. */
+ OP (FI, A, B, C, D, 0, 6, 0xf4292244);
+ OP (FI, D, A, B, C, 7, 10, 0x432aff97);
+ OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
+ OP (FI, B, C, D, A, 5, 21, 0xfc93a039);
+ OP (FI, A, B, C, D, 12, 6, 0x655b59c3);
+ OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92);
+ OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
+ OP (FI, B, C, D, A, 1, 21, 0x85845dd1);
+ OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f);
+ OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
+ OP (FI, C, D, A, B, 6, 15, 0xa3014314);
+ OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
+ OP (FI, A, B, C, D, 4, 6, 0xf7537e82);
+ OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
+ OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
+ OP (FI, B, C, D, A, 9, 21, 0xeb86d391);
+
+ /* Add the starting values of the context. */
+ A += A_save;
+ B += B_save;
+ C += C_save;
+ D += D_save;
+ }
+
+ /* Put checksum in context given as argument. */
+ ctx->A = A;
+ ctx->B = B;
+ ctx->C = C;
+ ctx->D = D;
+}
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