summaryrefslogtreecommitdiff
path: root/innobase/include/ut0rnd.ic
diff options
context:
space:
mode:
authorunknown <monty@donna.mysql.com>2001-02-17 14:19:19 +0200
committerunknown <monty@donna.mysql.com>2001-02-17 14:19:19 +0200
commit2662b59306ef0cd495fa6e2edf7129e58a11393a (patch)
treebfe39951a73e906579ab819bf5198ad8f3a64a36 /innobase/include/ut0rnd.ic
parent66de55a56bdcf2f7a9c0c4f8e19b3e761475e202 (diff)
downloadmariadb-git-2662b59306ef0cd495fa6e2edf7129e58a11393a.tar.gz
Added Innobase to source distribution
Docs/manual.texi: Added Innobase documentation configure.in: Incremented version include/my_base.h: Added option for Innobase myisam/mi_check.c: cleanup mysql-test/t/bdb.test: cleanup mysql-test/t/innobase.test: Extended with new tests from bdb.test mysql-test/t/merge.test: Added test of SHOW create mysys/my_init.c: Fix for UNIXWARE 7 scripts/mysql_install_db.sh: Always write how to start mysqld scripts/safe_mysqld.sh: Fixed type sql/ha_innobase.cc: Update to new version sql/ha_innobase.h: Update to new version sql/handler.h: Added 'update_table_comment()' and 'append_create_info()' sql/sql_delete.cc: Fixes for Innobase sql/sql_select.cc: Fixes for Innobase sql/sql_show.cc: Append create information (for MERGE tables) sql/sql_update.cc: Fixes for Innobase
Diffstat (limited to 'innobase/include/ut0rnd.ic')
-rw-r--r--innobase/include/ut0rnd.ic222
1 files changed, 222 insertions, 0 deletions
diff --git a/innobase/include/ut0rnd.ic b/innobase/include/ut0rnd.ic
new file mode 100644
index 00000000000..e166a26fe86
--- /dev/null
+++ b/innobase/include/ut0rnd.ic
@@ -0,0 +1,222 @@
+/******************************************************************
+Random numbers and hashing
+
+(c) 1994, 1995 Innobase Oy
+
+Created 5/30/1994 Heikki Tuuri
+*******************************************************************/
+
+#define UT_HASH_RANDOM_MASK 1463735687
+#define UT_HASH_RANDOM_MASK2 1653893711
+#define UT_RND1 151117737
+#define UT_RND2 119785373
+#define UT_RND3 85689495
+#define UT_RND4 76595339
+#define UT_SUM_RND2 98781234
+#define UT_SUM_RND3 126792457
+#define UT_SUM_RND4 63498502
+#define UT_XOR_RND1 187678878
+#define UT_XOR_RND2 143537923
+
+extern ulint ut_rnd_ulint_counter;
+
+/************************************************************
+This is used to set the random number seed. */
+UNIV_INLINE
+void
+ut_rnd_set_seed(
+/*============*/
+ ulint seed) /* in: seed */
+{
+ ut_rnd_ulint_counter = seed;
+}
+
+/************************************************************
+The following function generates a series of 'random' ulint integers. */
+UNIV_INLINE
+ulint
+ut_rnd_gen_next_ulint(
+/*==================*/
+ /* out: the next 'random' number */
+ ulint rnd) /* in: the previous random number value */
+{
+ ulint n_bits;
+
+ n_bits = 8 * sizeof(ulint);
+
+ rnd = UT_RND2 * rnd + UT_SUM_RND3;
+ rnd = UT_XOR_RND1 ^ rnd;
+ rnd = (rnd << 20) + (rnd >> (n_bits - 20));
+ rnd = UT_RND3 * rnd + UT_SUM_RND4;
+ rnd = UT_XOR_RND2 ^ rnd;
+ rnd = (rnd << 20) + (rnd >> (n_bits - 20));
+ rnd = UT_RND1 * rnd + UT_SUM_RND2;
+
+ return(rnd);
+}
+
+/************************************************************
+The following function generates 'random' ulint integers which
+enumerate the value space of ulint integers in a pseudo random
+fashion. Note that the same integer is repeated always after
+2 to power 32 calls to the generator (if ulint is 32-bit). */
+UNIV_INLINE
+ulint
+ut_rnd_gen_ulint(void)
+/*==================*/
+ /* out: the 'random' number */
+{
+ ulint rnd;
+ ulint n_bits;
+
+ n_bits = 8 * sizeof(ulint);
+
+ ut_rnd_ulint_counter =
+ UT_RND1 * ut_rnd_ulint_counter + UT_RND2;
+
+ rnd = ut_rnd_gen_next_ulint(ut_rnd_ulint_counter);
+
+ return(rnd);
+}
+
+/************************************************************
+Generates a random integer from a given interval. */
+UNIV_INLINE
+ulint
+ut_rnd_interval(
+/*============*/
+ /* out: the 'random' number */
+ ulint low, /* in: low limit; can generate also this value */
+ ulint high) /* in: high limit; can generate also this value */
+{
+ ulint rnd;
+
+ ut_ad(high >= low);
+
+ if (low == high) {
+
+ return(low);
+ }
+
+ rnd = ut_rnd_gen_ulint();
+
+ return(low + (rnd % (high - low + 1)));
+}
+
+/*************************************************************
+Generates a random iboolean value. */
+UNIV_INLINE
+ibool
+ut_rnd_gen_ibool(void)
+/*=================*/
+ /* out: the random value */
+{
+ ulint x;
+
+ x = ut_rnd_gen_ulint();
+
+ if (((x >> 20) + (x >> 15)) & 1) {
+
+ return(TRUE);
+ }
+
+ return(FALSE);
+}
+
+/***********************************************************
+The following function generates a hash value for a ulint integer
+to a hash table of size table_size, which should be a prime
+or some random number for the hash table to work reliably. */
+UNIV_INLINE
+ulint
+ut_hash_ulint(
+/*=========*/
+ /* out: hash value */
+ ulint key, /* in: value to be hashed */
+ ulint table_size) /* in: hash table size */
+{
+ key = key ^ UT_HASH_RANDOM_MASK2;
+
+ return(key % table_size);
+}
+
+/*****************************************************************
+Folds a pair of ulints. */
+UNIV_INLINE
+ulint
+ut_fold_ulint_pair(
+/*===============*/
+ /* out: folded value */
+ ulint n1, /* in: ulint */
+ ulint n2) /* in: ulint */
+{
+ return(((((n1 ^ n2 ^ UT_HASH_RANDOM_MASK2) << 8) + n1)
+ ^ UT_HASH_RANDOM_MASK) + n2);
+}
+
+/*****************************************************************
+Folds a dulint. */
+UNIV_INLINE
+ulint
+ut_fold_dulint(
+/*===========*/
+ /* out: folded value */
+ dulint d) /* in: dulint */
+{
+ return(ut_fold_ulint_pair(ut_dulint_get_low(d),
+ ut_dulint_get_high(d)));
+}
+
+/*****************************************************************
+Folds a character string ending in the null character. */
+UNIV_INLINE
+ulint
+ut_fold_string(
+/*===========*/
+ /* out: folded value */
+ char* str) /* in: null-terminated string */
+{
+ #ifdef UNIV_DEBUG
+ ulint i = 0;
+ #endif
+ ulint fold = 0;
+
+ ut_ad(str);
+
+ while (*str != '\0') {
+
+ #ifdef UNIV_DEBUG
+ i++;
+ ut_a(i < 100);
+ #endif
+
+ fold = ut_fold_ulint_pair(fold, (ulint)(*str));
+ str++;
+ }
+
+ return(fold);
+}
+
+/*****************************************************************
+Folds a binary string. */
+UNIV_INLINE
+ulint
+ut_fold_binary(
+/*===========*/
+ /* out: folded value */
+ byte* str, /* in: string of bytes */
+ ulint len) /* in: length */
+{
+ ulint i;
+ ulint fold = 0;
+
+ ut_ad(str);
+
+ for (i = 0; i < len; i++) {
+ fold = ut_fold_ulint_pair(fold, (ulint)(*str));
+
+ str++;
+ }
+
+ return(fold);
+}