1 files changed, 141 insertions, 0 deletions
diff --git a/lib/md5-stream.c b/lib/md5-stream.c
new file mode 100644
index 0000000..07c639f
--- /dev/null
+++ b/lib/md5-stream.c
@@ -0,0 +1,141 @@
+/* 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) 1995-1997, 1999-2001, 2005-2006, 2008-2022 Free Software
+   Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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/>.  */
+
+/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.  */
+
+#include <config.h>
+
+/* Specification.  */
+#if HAVE_OPENSSL_MD5
+# define GL_OPENSSL_INLINE _GL_EXTERN_INLINE
+#endif
+#include "md5.h"
+
+#include <stdlib.h>
+
+#if USE_UNLOCKED_IO
+# include "unlocked-io.h"
+#endif
+
+#include "af_alg.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_stream __md5_stream
+#endif
+
+#define BLOCKSIZE 32768
+#if BLOCKSIZE % 64 != 0
+# error "invalid BLOCKSIZE"
+#endif
+
+/* 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 (FILE *stream, void *resblock)
+{
+  switch (afalg_stream (stream, "md5", resblock, MD5_DIGEST_SIZE))
+    {
+    case 0: return 0;
+    case -EIO: return 1;
+    }
+
+  char *buffer = malloc (BLOCKSIZE + 72);
+  if (!buffer)
+    return 1;
+
+  struct md5_ctx ctx;
+  md5_init_ctx (&ctx);
+  size_t sum;
+
+  /* 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)
+        {
+          /* Either process a partial fread() from this loop,
+             or the fread() in afalg_stream may have gotten EOF.
+             We need to avoid a subsequent fread() as EOF may
+             not be sticky.  For details of such systems, see:
+             https://sourceware.org/bugzilla/show_bug.cgi?id=1190  */
+          if (feof (stream))
+            goto process_partial_block;
+
+          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;
+            }
+        }
+
+      /* Process buffer with BLOCKSIZE bytes.  Note that
+         BLOCKSIZE % 64 == 0
+       */
+      md5_process_block (buffer, BLOCKSIZE, &ctx);
+    }
+
+process_partial_block:
+
+  /* Process any remaining bytes.  */
+  if (sum > 0)
+    md5_process_bytes (buffer, sum, &ctx);
+
+  /* Construct result in desired memory.  */
+  md5_finish_ctx (&ctx, resblock);
+  free (buffer);
+  return 0;
+}
+
+/*
+ * Hey Emacs!
+ * Local Variables:
+ * coding: utf-8
+ * End:
+ */