Adding upstream version 1:10.11.6.upstream/1%10.11.6

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 205 insertions, 0 deletions

diff --git a/mysys/lf_dynarray.c b/mysys/lf_dynarray.c
new file mode 100644
index 00000000..6a4ea3d3
--- /dev/null
+++ b/mysys/lf_dynarray.c
@@ -0,0 +1,205 @@
+/* Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
+
+   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 Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */
+
+/*
+  Analog of DYNAMIC_ARRAY that never reallocs
+  (so no pointer into the array may ever become invalid).
+
+  Memory is allocated in non-contiguous chunks.
+  This data structure is not space efficient for sparse arrays.
+
+  Every element is aligned to sizeof(element) boundary
+  (to avoid false sharing if element is big enough).
+
+  LF_DYNARRAY is a recursive structure. On the zero level
+  LF_DYNARRAY::level[0] it's an array of LF_DYNARRAY_LEVEL_LENGTH elements,
+  on the first level it's an array of LF_DYNARRAY_LEVEL_LENGTH pointers
+  to arrays of elements, on the second level it's an array of pointers
+  to arrays of pointers to arrays of elements. And so on.
+
+  With four levels the number of elements is limited to 4311810304
+  (but as in all functions index is uint, the real limit is 2^32-1)
+
+  Actually, it's wait-free, not lock-free ;-)
+*/
+
+#include "mysys_priv.h"
+#include <m_string.h>
+#include <lf.h>
+
+void lf_dynarray_init(LF_DYNARRAY *array, uint element_size)
+{
+  bzero(array, sizeof(*array));
+  array->size_of_element= element_size;
+}
+
+static void recursive_free(void **alloc, int level)
+{
+  if (!alloc)
+    return;
+
+  if (level)
+  {
+    int i;
+    for (i= 0; i < LF_DYNARRAY_LEVEL_LENGTH; i++)
+      recursive_free(alloc[i], level-1);
+    my_free(alloc);
+  }
+  else
+    my_free(alloc[-1]);
+}
+
+void lf_dynarray_destroy(LF_DYNARRAY *array)
+{
+  int i;
+  for (i= 0; i < LF_DYNARRAY_LEVELS; i++)
+    recursive_free(array->level[i], i);
+}
+
+static const ulong dynarray_idxes_in_prev_levels[LF_DYNARRAY_LEVELS]=
+{
+  0, /* +1 here to to avoid -1's below */
+  LF_DYNARRAY_LEVEL_LENGTH,
+  LF_DYNARRAY_LEVEL_LENGTH * LF_DYNARRAY_LEVEL_LENGTH +
+    LF_DYNARRAY_LEVEL_LENGTH,
+  LF_DYNARRAY_LEVEL_LENGTH * LF_DYNARRAY_LEVEL_LENGTH *
+    LF_DYNARRAY_LEVEL_LENGTH + LF_DYNARRAY_LEVEL_LENGTH *
+    LF_DYNARRAY_LEVEL_LENGTH + LF_DYNARRAY_LEVEL_LENGTH
+};
+
+static const ulong dynarray_idxes_in_prev_level[LF_DYNARRAY_LEVELS]=
+{
+  0, /* +1 here to to avoid -1's below */
+  LF_DYNARRAY_LEVEL_LENGTH,
+  LF_DYNARRAY_LEVEL_LENGTH * LF_DYNARRAY_LEVEL_LENGTH,
+  LF_DYNARRAY_LEVEL_LENGTH * LF_DYNARRAY_LEVEL_LENGTH *
+    LF_DYNARRAY_LEVEL_LENGTH,
+};
+
+/*
+  Returns a valid lvalue pointer to the element number 'idx'.
+  Allocates memory if necessary.
+*/
+void *lf_dynarray_lvalue(LF_DYNARRAY *array, uint idx)
+{
+  void * ptr, * volatile * ptr_ptr= 0;
+  int i;
+
+  for (i= LF_DYNARRAY_LEVELS-1; idx < dynarray_idxes_in_prev_levels[i]; i--)
+    /* no-op */;
+  ptr_ptr= &array->level[i];
+  idx-= dynarray_idxes_in_prev_levels[i];
+  for (; i > 0; i--)
+  {
+    if (!(ptr= *ptr_ptr))
+    {
+      void *alloc= my_malloc(key_memory_lf_dynarray, LF_DYNARRAY_LEVEL_LENGTH *
+                             sizeof(void *), MYF(MY_WME|MY_ZEROFILL));
+      if (unlikely(!alloc))
+        return(NULL);
+      if (my_atomic_casptr(ptr_ptr, &ptr, alloc))
+        ptr= alloc;
+      else
+        my_free(alloc);
+    }
+    ptr_ptr= ((void **)ptr) + idx / dynarray_idxes_in_prev_level[i];
+    idx%= dynarray_idxes_in_prev_level[i];
+  }
+  if (!(ptr= *ptr_ptr))
+  {
+    uchar *alloc, *data;
+    alloc= my_malloc(key_memory_lf_dynarray,
+                     LF_DYNARRAY_LEVEL_LENGTH * array->size_of_element +
+                     MY_MAX(array->size_of_element, sizeof(void *)),
+                     MYF(MY_WME|MY_ZEROFILL));
+    if (unlikely(!alloc))
+      return(NULL);
+    /* reserve the space for free() address */
+    data= alloc + sizeof(void *);
+    { /* alignment */
+      intptr mod= ((intptr)data) % array->size_of_element;
+      if (mod)
+        data+= array->size_of_element - mod;
+    }
+    ((void **)data)[-1]= alloc; /* free() will need the original pointer */
+    if (my_atomic_casptr(ptr_ptr, &ptr, data))
+      ptr= data;
+    else
+      my_free(alloc);
+  }
+  return ((uchar*)ptr) + array->size_of_element * idx;
+}
+
+/*
+  Returns a pointer to the element number 'idx'
+  or NULL if an element does not exists
+*/
+void *lf_dynarray_value(LF_DYNARRAY *array, uint idx)
+{
+  void * ptr, * volatile * ptr_ptr= 0;
+  int i;
+
+  for (i= LF_DYNARRAY_LEVELS-1; idx < dynarray_idxes_in_prev_levels[i]; i--)
+    /* no-op */;
+  ptr_ptr= &array->level[i];
+  idx-= dynarray_idxes_in_prev_levels[i];
+  for (; i > 0; i--)
+  {
+    if (!(ptr= *ptr_ptr))
+      return(NULL);
+    ptr_ptr= ((void **)ptr) + idx / dynarray_idxes_in_prev_level[i];
+    idx %= dynarray_idxes_in_prev_level[i];
+  }
+  if (!(ptr= *ptr_ptr))
+    return(NULL);
+  return ((uchar*)ptr) + array->size_of_element * idx;
+}
+
+static int recursive_iterate(LF_DYNARRAY *array, void *ptr, int level,
+                             lf_dynarray_func func, void *arg)
+{
+  int res, i;
+  if (!ptr)
+    return 0;
+  if (!level)
+    return func(ptr, arg);
+  for (i= 0; i < LF_DYNARRAY_LEVEL_LENGTH; i++)
+    if ((res= recursive_iterate(array, ((void **)ptr)[i], level-1, func, arg)))
+      return res;
+  return 0;
+}
+
+/*
+  Calls func(array, arg) on every array of LF_DYNARRAY_LEVEL_LENGTH elements
+  in lf_dynarray.
+
+  DESCRIPTION
+    lf_dynarray consists of a set of arrays, LF_DYNARRAY_LEVEL_LENGTH elements
+    each. lf_dynarray_iterate() calls user-supplied function on every array
+    from the set. It is the fastest way to scan the array, faster than
+      for (i=0; i < N; i++) { func(lf_dynarray_value(dynarray, i)); }
+
+  NOTE
+    if func() returns non-zero, the scan is aborted
+*/
+int lf_dynarray_iterate(LF_DYNARRAY *array, lf_dynarray_func func, void *arg)
+{
+  int i, res;
+  for (i= 0; i < LF_DYNARRAY_LEVELS; i++)
+    if ((res= recursive_iterate(array, array->level[i], i, func, arg)))
+      return res;
+  return 0;
+}
+