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libmariadb/ma_array.c

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+/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
+                 2016 MariaDB Corporation AB
+   
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public
+   License as published by the Free Software Foundation; either
+   version 2 of the License, or (at your option) any later version.
+   
+   This library 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
+   Library General Public License for more details.
+   
+   You should have received a copy of the GNU Library General Public
+   License along with this library; if not, write to the Free
+   Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+   MA 02111-1301, USA */
+
+/* Handling of arrays that can grow dynamically. */
+
+#undef SAFEMALLOC /* Problems with threads */
+
+#include <ma_global.h>
+#include <ma_sys.h>
+#include "ma_string.h"
+#include <memory.h>
+
+/*
+  Initiate array and alloc space for init_alloc elements. Array is usable
+  even if space allocation failed
+*/
+
+my_bool ma_init_dynamic_array(DYNAMIC_ARRAY *array, uint element_size,
+                              uint init_alloc, uint alloc_increment CALLER_INFO_PROTO)
+{
+  if (!alloc_increment)
+  {
+    alloc_increment=max((8192-MALLOC_OVERHEAD)/element_size,16);
+    if (init_alloc > 8 && alloc_increment > init_alloc * 2)
+      alloc_increment=init_alloc*2;
+  }
+
+  if (!init_alloc)
+    init_alloc=alloc_increment;
+  array->elements=0;
+  array->max_element=init_alloc;
+  array->alloc_increment=alloc_increment;
+  array->size_of_element=element_size;
+  if (!(array->buffer=(char*) malloc(element_size*init_alloc)))
+  {
+    array->max_element=0;
+    return(TRUE);
+  }
+  return(FALSE);
+}
+
+
+my_bool ma_insert_dynamic(DYNAMIC_ARRAY *array, void *element)
+{
+  void *buffer;
+  if (array->elements == array->max_element)
+  {						/* Call only when necessary */
+    if (!(buffer=ma_alloc_dynamic(array)))
+      return TRUE;
+  }
+  else
+  {
+    buffer=array->buffer+(array->elements * array->size_of_element);
+    array->elements++;
+  }
+  memcpy(buffer,element,(size_t) array->size_of_element);
+  return FALSE;
+}
+
+
+	/* Alloc room for one element */
+
+unsigned char *ma_alloc_dynamic(DYNAMIC_ARRAY *array)
+{
+  if (array->elements == array->max_element)
+  {
+    char *new_ptr;
+    if (!(new_ptr=(char*) realloc(array->buffer,(array->max_element+
+			          array->alloc_increment)*
+				   array->size_of_element)))
+      return 0;
+    array->buffer=new_ptr;
+    array->max_element+=array->alloc_increment;
+  }
+  return (unsigned char *)array->buffer+(array->elements++ * array->size_of_element);
+}
+
+
+	/* remove last element from array and return it */
+
+unsigned char *ma_pop_dynamic(DYNAMIC_ARRAY *array)
+{
+  if (array->elements)
+    return (unsigned char *)array->buffer+(--array->elements * array->size_of_element);
+  return 0;
+}
+
+
+my_bool ma_set_dynamic(DYNAMIC_ARRAY *array, void * element, uint idx)
+{
+  if (idx >= array->elements)
+  {
+    if (idx >= array->max_element)
+    {
+      uint size;
+      char *new_ptr;
+      size=(idx+array->alloc_increment)/array->alloc_increment;
+      size*= array->alloc_increment;
+      if (!(new_ptr=(char*) realloc(array->buffer,size*
+			            array->size_of_element)))
+	return TRUE;
+      array->buffer=new_ptr;
+      array->max_element=size;
+    }
+    memset((array->buffer+array->elements*array->size_of_element), 0,
+	  (idx - array->elements)*array->size_of_element);
+    array->elements=idx+1;
+  }
+  memcpy(array->buffer+(idx * array->size_of_element),element,
+	 (size_t) array->size_of_element);
+  return FALSE;
+}
+
+
+void ma_get_dynamic(DYNAMIC_ARRAY *array, void * element, uint idx)
+{
+  if (idx >= array->elements)
+  {
+    memset(element, 0, array->size_of_element);
+    return;
+  }
+  memcpy(element,array->buffer+idx*array->size_of_element,
+	 (size_t) array->size_of_element);
+}
+
+
+void ma_delete_dynamic(DYNAMIC_ARRAY *array)
+{
+  if (array->buffer)
+  {
+    free(array->buffer);
+    array->buffer=0;
+    array->elements=array->max_element=0;
+  }
+}
+
+
+void ma_delete_dynamic_element(DYNAMIC_ARRAY *array, uint idx)
+{
+  char *ptr=array->buffer+array->size_of_element*idx;
+  array->elements--;
+  memmove(ptr,ptr+array->size_of_element,
+	  (array->elements-idx)*array->size_of_element);
+}
+
+
+void ma_freeze_size(DYNAMIC_ARRAY *array)
+{
+  uint elements=max(array->elements,1);
+
+  if (array->buffer && array->max_element != elements)
+  {
+    array->buffer=(char*) realloc(array->buffer,
+			          elements*array->size_of_element);
+    array->max_element=elements;
+  }
+}