diff options
Diffstat (limited to 'lib/libc/uuid/uuid_compare.c')
| -rw-r--r-- | lib/libc/uuid/uuid_compare.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/lib/libc/uuid/uuid_compare.c b/lib/libc/uuid/uuid_compare.c new file mode 100644 index 0000000..13d7c27 --- /dev/null +++ b/lib/libc/uuid/uuid_compare.c @@ -0,0 +1,76 @@ +/*- + * Copyright (c) 2002,2005 Marcel Moolenaar + * Copyright (c) 2002 Hiten Mahesh Pandya + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. 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 AUTHOR 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 AUTHOR 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. + * + * $FreeBSD$ + */ + +#include <string.h> +#include <uuid.h> + +/* A macro used to improve the readability of uuid_compare(). */ +#define DIFF_RETURN(a, b, field) do { \ + if ((a)->field != (b)->field) \ + return (((a)->field < (b)->field) ? -1 : 1); \ +} while (0) + +/* + * uuid_compare() - compare two UUIDs. + * See also: + * http://www.opengroup.org/onlinepubs/009629399/uuid_compare.htm + * + * NOTE: Either UUID can be NULL, meaning a nil UUID. nil UUIDs are smaller + * than any non-nil UUID. + */ +int32_t +uuid_compare(const uuid_t *a, const uuid_t *b, uint32_t *status) +{ + int res; + + if (status != NULL) + *status = uuid_s_ok; + + /* Deal with NULL or equal pointers. */ + if (a == b) + return (0); + if (a == NULL) + return ((uuid_is_nil(b, NULL)) ? 0 : -1); + if (b == NULL) + return ((uuid_is_nil(a, NULL)) ? 0 : 1); + + /* We have to compare the hard way. */ + DIFF_RETURN(a, b, time_low); + DIFF_RETURN(a, b, time_mid); + DIFF_RETURN(a, b, time_hi_and_version); + DIFF_RETURN(a, b, clock_seq_hi_and_reserved); + DIFF_RETURN(a, b, clock_seq_low); + + res = memcmp(a->node, b->node, sizeof(a->node)); + if (res) + return ((res < 0) ? -1 : 1); + return (0); +} + +#undef DIFF_RETURN |
