--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2008-01-30  Peter Palfrader  <weasel@debian.org>
+
+	sha1: remove the result buffer alignment constraint
+	* lib/sha1.c (set_uint32): New function.
+	(sha1_read_ctx): Rewrite to remove the result buffer alignment
+	constraint.
+	(sha1_finish_ctx): Remove comment warning about alignment constraint.
+	* lib/sha1.h: Likewise.
+
 2008-01-30  Andreas Schwab  <schwab@suse.de>
             Bruno Haible  <bruno@clisp.org>
 

--- a/lib/sha1.c
+++ b/lib/sha1.c
@@ -67,28 +67,32 @@
   ctx->buflen = 0;
 }
 
-/* Put result from CTX in first 20 bytes following RESBUF.  The result
-   must be in little endian byte order.
+/* Copy the 4 byte value from v into the memory location pointed to by *cp,
+   If your architecture allows unaligned access this is equivalent to
+   * (uint32_t *) cp = v  */
+void
+set_uint32 (char *cp, uint32_t v)
+{
+  memcpy (cp, &v, 4);
+}
 
-   IMPORTANT: On some systems it is required that RESBUF is correctly
-   aligned for a 32-bit value.  */
+/* Put result from CTX in first 20 bytes following RESBUF.  The result
+   must be in little endian byte order.  */
 void *
 sha1_read_ctx (const struct sha1_ctx *ctx, void *resbuf)
 {
-  ((uint32_t *) resbuf)[0] = SWAP (ctx->A);
-  ((uint32_t *) resbuf)[1] = SWAP (ctx->B);
-  ((uint32_t *) resbuf)[2] = SWAP (ctx->C);
-  ((uint32_t *) resbuf)[3] = SWAP (ctx->D);
-  ((uint32_t *) resbuf)[4] = SWAP (ctx->E);
+  char *r = resbuf;
+  set_uint32 (r + 0*4, SWAP (ctx->A));
+  set_uint32 (r + 1*4, SWAP (ctx->B));
+  set_uint32 (r + 2*4, SWAP (ctx->C));
+  set_uint32 (r + 3*4, SWAP (ctx->D));
+  set_uint32 (r + 4*4, SWAP (ctx->E));
 
   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-bit value.  */
+   prolog according to the standard and write the result to RESBUF.  */
 void *
 sha1_finish_ctx (struct sha1_ctx *ctx, void *resbuf)
 {

--- a/lib/sha1.h
+++ b/lib/sha1.h
@@ -1,6 +1,7 @@
 /* Declarations of functions and data types used for SHA1 sum
    library functions.
-   Copyright (C) 2000, 2001, 2003, 2005, 2006 Free Software Foundation, Inc.
+   Copyright (C) 2000, 2001, 2003, 2005, 2006, 2008
+   Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by the
@@ -57,19 +58,13 @@
 /* Process the remaining bytes in the buffer and put result from CTX
    in first 20 bytes following RESBUF.  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.
-
-   IMPORTANT: On some systems it is required that RESBUF be correctly
-   aligned for a 32 bits value.  */
+   ASCII representation of the message digest.  */
 extern void *sha1_finish_ctx (struct sha1_ctx *ctx, void *resbuf);
 
 
 /* Put result from CTX in first 20 bytes following RESBUF.  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.
-
-   IMPORTANT: On some systems it is required that RESBUF is correctly
-   aligned for a 32 bits value.  */
+   to the wanted ASCII representation of the message digest.  */
 extern void *sha1_read_ctx (const struct sha1_ctx *ctx, void *resbuf);