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+/* Functions to compute MD2 message digest of files or memory blocks.
+ according to the definition of MD2 in RFC 1319 from April 1992.
+ Copyright (C) 1995-1997, 1999-2003, 2005-2006, 2008-2022 Free Software
+ Foundation, Inc.
+
+ This file is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as
+ published by the Free Software Foundation; either version 2.1 of the
+ License, or (at your option) any later version.
+
+ This file 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 Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+/* Adapted by Simon Josefsson from public domain Libtomcrypt 1.06 by
+ Tom St Denis. */
+
+#include <config.h>
+
+/* Specification. */
+#include "md2.h"
+
+#include <stdlib.h>
+
+#if USE_UNLOCKED_IO
+# include "unlocked-io.h"
+#endif
+
+#define BLOCKSIZE 32768
+#if BLOCKSIZE % 64 != 0
+# error "invalid BLOCKSIZE"
+#endif
+
+/* Compute MD2 message digest for bytes read from STREAM. The
+ resulting message digest number will be written into the 16 bytes
+ beginning at RESBLOCK. */
+int
+md2_stream (FILE *stream, void *resblock)
+{
+ struct md2_ctx ctx;
+ size_t sum;
+
+ char *buffer = malloc (BLOCKSIZE + 72);
+ if (!buffer)
+ return 1;
+
+ /* Initialize the computation context. */
+ md2_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. */
+ while (1)
+ {
+ n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
+
+ sum += n;
+
+ if (sum == BLOCKSIZE)
+ break;
+
+ if (n == 0)
+ {
+ /* Check for the error flag IFF N == 0, so that we don't
+ exit the loop after a partial read due to e.g., EAGAIN
+ or EWOULDBLOCK. */
+ if (ferror (stream))
+ {
+ free (buffer);
+ return 1;
+ }
+ goto process_partial_block;
+ }
+
+ /* We've read at least one byte, so ignore errors. But always
+ check for EOF, since feof may be true even though N > 0.
+ Otherwise, we could end up calling fread after EOF. */
+ if (feof (stream))
+ goto process_partial_block;
+ }
+
+ /* Process buffer with BLOCKSIZE bytes. Note that
+ BLOCKSIZE % 64 == 0
+ */
+ md2_process_block (buffer, BLOCKSIZE, &ctx);
+ }
+
+process_partial_block:;
+
+ /* Process any remaining bytes. */
+ if (sum > 0)
+ md2_process_bytes (buffer, sum, &ctx);
+
+ /* Construct result in desired memory. */
+ md2_finish_ctx (&ctx, resblock);
+ free (buffer);
+ return 0;
+}