Add implementation

1 files changed, 78 insertions, 0 deletions

diff --git a/mysql/my_alloc.h b/mysql/my_alloc.h
new file mode 100644
index 0000000..d236c93
--- /dev/null
+++ b/mysql/my_alloc.h
@@ -0,0 +1,78 @@
+/* Copyright (c) 2000, 2016, 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 02110-1301  USA */
+
+/* 
+   Data structures for mysys/my_alloc.c (root memory allocator)
+*/
+
+#ifndef _my_alloc_h
+#define _my_alloc_h
+
+#define ALLOC_MAX_BLOCK_TO_DROP			4096
+#define ALLOC_MAX_BLOCK_USAGE_BEFORE_DROP	10
+
+/* PSI_memory_key */
+#include "mysql/psi/psi_memory.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct st_used_mem
+{				   /* struct for once_alloc (block) */
+  struct st_used_mem *next;	   /* Next block in use */
+  unsigned int	left;		   /* memory left in block  */
+  unsigned int	size;		   /* size of block */
+} USED_MEM;
+
+
+typedef struct st_mem_root
+{
+  USED_MEM *free;                  /* blocks with free memory in it */
+  USED_MEM *used;                  /* blocks almost without free memory */
+  USED_MEM *pre_alloc;             /* preallocated block */
+  /* if block have less memory it will be put in 'used' list */
+  size_t min_malloc;
+  size_t block_size;               /* initial block size */
+  unsigned int block_num;          /* allocated blocks counter */
+  /* 
+     first free block in queue test counter (if it exceed 
+     MAX_BLOCK_USAGE_BEFORE_DROP block will be dropped in 'used' list)
+  */
+  unsigned int first_block_usage;
+
+  /*
+    Maximum amount of memory this mem_root can hold. A value of 0
+    implies there is no limit.
+  */
+  size_t max_capacity;
+
+  /* Allocated size for this mem_root */
+
+  size_t allocated_size;
+
+  /* Enable this for error reporting if capacity is exceeded */
+  my_bool error_for_capacity_exceeded;
+
+  void (*error_handler)(void);
+
+  PSI_memory_key m_psi_key;
+} MEM_ROOT;
+
+#ifdef  __cplusplus
+}
+#endif
+
+#endif