diff options
Diffstat (limited to 'src/util/support/bcmp.c')
-rw-r--r-- | src/util/support/bcmp.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/src/util/support/bcmp.c b/src/util/support/bcmp.c new file mode 100644 index 000000000..71728a687 --- /dev/null +++ b/src/util/support/bcmp.c @@ -0,0 +1,44 @@ +/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */ +/* util/support/bitcmp.c - Constant-time byte comparison function */ +/* + * Copyright (C) 2013 by the Massachusetts Institute of Technology. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, + * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "k5-platform.h" + +int +k5_bcmp(const void *p1, const void *p2, size_t n) +{ + const unsigned char *c1 = p1, *c2 = p2; + unsigned char x = 0; + + for (; n > 0; c1++, c2++, n--) + x |= *c1 ^ *c2; + return x; +} |