lib/uuid.h

   1 /* Copyright (c) 2008, 2009, 2010 Nicira Networks
   2  *
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #ifndef UUID_H
  17 #define UUID_H 1
  18
  19 #include <stdbool.h>
  20 #include <stddef.h>
  21 #include <stdint.h>
  22 #include "util.h"
  23
  24 #define UUID_BIT 128            /* Number of bits in a UUID. */
  25 #define UUID_OCTET (UUID_BIT / 8) /* Number of bytes in a UUID. */
  26
  27 /* A Universally Unique IDentifier (UUID) compliant with RFC 4122.
  28  *
  29  * Each of the parts is stored in host byte order, but the parts themselves are
  30  * ordered from left to right.  That is, (parts[0] >> 24) is the first 8 bits
  31  * of the UUID when output in the standard form, and (parts[3] & 0xff) is the
  32  * final 8 bits. */
  33 struct uuid {
  34     uint32_t parts[4];
  35 };
  36 BUILD_ASSERT_DECL(sizeof(struct uuid) == UUID_OCTET);
  37
  38 /* Formats a UUID as a string, in the conventional format.
  39  *
  40  * Example:
  41  *   struct uuid uuid = ...;
  42  *   printf("This UUID is "UUID_FMT"\n", UUID_ARGS(&uuid));
  43  *
  44  */
  45 #define UUID_LEN 36
  46 #define UUID_FMT "%08x-%04x-%04x-%04x-%04x%08x"
  47 #define UUID_ARGS(UUID)                             \
  48     ((unsigned int) ((UUID)->parts[0])),            \
  49     ((unsigned int) ((UUID)->parts[1] >> 16)),      \
  50     ((unsigned int) ((UUID)->parts[1] & 0xffff)),   \
  51     ((unsigned int) ((UUID)->parts[2] >> 16)),      \
  52     ((unsigned int) ((UUID)->parts[2] & 0xffff)),   \
  53     ((unsigned int) ((UUID)->parts[3]))
  54
  55 /* Returns a hash value for 'uuid'.  This hash value is the same regardless of
  56  * whether we are running on a 32-bit or 64-bit or big-endian or little-endian
  57  * architecture. */
  58 static inline size_t
  59 uuid_hash(const struct uuid *uuid)
  60 {
  61     return uuid->parts[0];
  62 }
  63
  64 /* Returns true if 'a == b', false otherwise. */
  65 static inline bool
  66 uuid_equals(const struct uuid *a, const struct uuid *b)
  67 {
  68     return (a->parts[0] == b->parts[0]
  69             && a->parts[1] == b->parts[1]
  70             && a->parts[2] == b->parts[2]
  71             && a->parts[3] == b->parts[3]);
  72 }
  73
  74 void uuid_init(void);
  75 void uuid_generate(struct uuid *);
  76 void uuid_zero(struct uuid *);
  77 bool uuid_is_zero(const struct uuid *);
  78 int uuid_compare_3way(const struct uuid *, const struct uuid *);
  79 bool uuid_from_string(struct uuid *, const char *);
  80 bool uuid_from_string_prefix(struct uuid *, const char *);
  81
  82 #endif /* vswitchd/cfgdb.h */