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

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

1 files changed, 246 insertions, 0 deletions

diff --git a/storage/myisam/mi_unique.c b/storage/myisam/mi_unique.c
new file mode 100644
index 00000000..ecc2b354
--- /dev/null
+++ b/storage/myisam/mi_unique.c
@@ -0,0 +1,246 @@
+/*
+   Copyright (c) 2000, 2010, Oracle and/or its affiliates
+   Copyright (c) 2020, MariaDB Corporation.
+
+   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 */
+
+/* Functions to check if a row is unique */
+
+#include "myisamdef.h"
+#include <m_ctype.h>
+
+my_bool mi_check_unique(MI_INFO *info, MI_UNIQUEDEF *def, const uchar *record,
+			ha_checksum unique_hash, my_off_t disk_pos)
+{
+  my_off_t lastpos=info->lastpos;
+  MI_KEYDEF *key= &info->s->keyinfo[def->key];
+  uchar *key_buff=info->lastkey2;
+  DBUG_ENTER("mi_check_unique");
+
+  /* We need to store the hash value as a key in the record, breaking const */
+  mi_unique_store(((uchar*) record)+key->seg->start, unique_hash);
+  _mi_make_key(info,def->key,key_buff,record,0);
+
+  /* The above changed info->lastkey2. Inform mi_rnext_same(). */
+  info->update&= ~HA_STATE_RNEXT_SAME;
+
+  if (_mi_search(info,info->s->keyinfo+def->key,key_buff,MI_UNIQUE_HASH_LENGTH,
+		 SEARCH_FIND,info->s->state.key_root[def->key]))
+  {
+    info->page_changed=1;			/* Can't optimize read next */
+    info->lastpos= lastpos;
+    DBUG_RETURN(0);				/* No matching rows */
+  }
+
+  for (;;)
+  {
+    if (info->lastpos != disk_pos &&
+	!(*info->s->compare_unique)(info,def,record,info->lastpos))
+    {
+      my_errno=HA_ERR_FOUND_DUPP_UNIQUE;
+      info->errkey= (int) def->key;
+      info->dupp_key_pos= info->lastpos;
+      info->page_changed=1;			/* Can't optimize read next */
+      info->lastpos=lastpos;
+      DBUG_PRINT("info",("Found duplicate"));
+      DBUG_RETURN(1);				/* Found identical  */
+    }
+    if (_mi_search_next(info,info->s->keyinfo+def->key, info->lastkey,
+			MI_UNIQUE_HASH_LENGTH, SEARCH_BIGGER,
+			info->s->state.key_root[def->key]) ||
+	memcmp(info->lastkey, key_buff, MI_UNIQUE_HASH_LENGTH))
+    {
+      info->page_changed=1;			/* Can't optimize read next */
+      info->lastpos=lastpos;
+      DBUG_RETURN(0);				/* end of tree */
+    }
+  }
+}
+
+
+/*
+  Calculate a hash for a row
+
+  TODO
+    Add support for bit fields
+*/
+
+ha_checksum mi_unique_hash(MI_UNIQUEDEF *def, const uchar *record)
+{
+  const uchar *pos, *end;
+  ha_checksum crc= 0;
+  ulong seed1=0, seed2= 4;
+  HA_KEYSEG *keyseg;
+
+  for (keyseg=def->seg ; keyseg < def->end ; keyseg++)
+  {
+    enum ha_base_keytype type=(enum ha_base_keytype) keyseg->type;
+    uint length=keyseg->length;
+
+    if (keyseg->null_bit)
+    {
+      if (record[keyseg->null_pos] & keyseg->null_bit)
+      {
+	/*
+	  Change crc in a way different from an empty string or 0.
+	  (This is an optimisation;  The code will work even if this isn't
+	  done)
+	*/
+	crc=((crc << 8) + 511+
+	     (crc >> (8*sizeof(ha_checksum)-8)));
+	continue;
+      }
+    }
+    pos= record+keyseg->start;
+    if (keyseg->flag & HA_VAR_LENGTH_PART)
+    {
+      uint pack_length=  keyseg->bit_start;
+      uint tmp_length= (pack_length == 1 ? (uint) *(uchar*) pos :
+                        uint2korr(pos));
+      pos+= pack_length;			/* Skip VARCHAR length */
+      set_if_smaller(length,tmp_length);
+    }
+    else if (keyseg->flag & HA_BLOB_PART)
+    {
+      uint tmp_length=_mi_calc_blob_length(keyseg->bit_start,pos);
+      memcpy((char**) &pos, pos+keyseg->bit_start, sizeof(char*));
+      if (!length || length > tmp_length)
+	length=tmp_length;			/* The whole blob */
+    }
+    end= pos+length;
+    if (type == HA_KEYTYPE_TEXT || type == HA_KEYTYPE_VARTEXT1 ||
+        type == HA_KEYTYPE_VARTEXT2)
+    {
+      my_ci_hash_sort(keyseg->charset,
+                      (const uchar*) pos, length,
+                      &seed1, &seed2);
+      crc^= seed1;
+    }
+    else
+      while (pos != end)
+	crc=((crc << 8) +
+	     (((uchar)  *(uchar*) pos++))) +
+	  (crc >> (8*sizeof(ha_checksum)-8));
+  }
+  return crc;
+}
+
+
+/*
+  compare unique key for two rows
+
+  TODO
+    Add support for bit fields
+
+  RETURN
+    0   if both rows have equal unique value
+    #   Rows are different
+*/
+
+int mi_unique_comp(MI_UNIQUEDEF *def, const uchar *a, const uchar *b,
+		   my_bool null_are_equal)
+{
+  const uchar *pos_a, *pos_b, *end;
+  HA_KEYSEG *keyseg;
+
+  for (keyseg=def->seg ; keyseg < def->end ; keyseg++)
+  {
+    enum ha_base_keytype type=(enum ha_base_keytype) keyseg->type;
+    uint a_length, b_length;
+    a_length= b_length= keyseg->length;
+
+    /* If part is NULL it's regarded as different */
+    if (keyseg->null_bit)
+    {
+      uint tmp;
+      if ((tmp=(a[keyseg->null_pos] & keyseg->null_bit)) !=
+	  (uint) (b[keyseg->null_pos] & keyseg->null_bit))
+	return 1;
+      if (tmp)
+      {
+	if (!null_are_equal)
+	  return 1;
+	continue;
+      }
+    }
+    pos_a= a+keyseg->start;
+    pos_b= b+keyseg->start;
+    if (keyseg->flag & HA_VAR_LENGTH_PART)
+    {
+      uint pack_length= keyseg->bit_start;
+      if (pack_length == 1)
+      {
+        a_length= (uint) *(uchar*) pos_a++;
+        b_length= (uint) *(uchar*) pos_b++;
+      }
+      else
+      {
+        a_length= uint2korr(pos_a);
+        b_length= uint2korr(pos_b);
+        pos_a+= 2;				/* Skip VARCHAR length */
+        pos_b+= 2;
+      }
+      set_if_smaller(a_length, keyseg->length); /* Safety */
+      set_if_smaller(b_length, keyseg->length); /* safety */
+    }
+    else if (keyseg->flag & HA_BLOB_PART)
+    {
+      /* Only compare 'length' characters if length != 0 */
+      a_length= _mi_calc_blob_length(keyseg->bit_start,pos_a);
+      b_length= _mi_calc_blob_length(keyseg->bit_start,pos_b);
+      /* Check that a and b are of equal length */
+      if (keyseg->length)
+      {
+        /*
+          This is used in some cases when we are not interested in comparing
+          the whole length of the blob.
+        */
+        set_if_smaller(a_length, keyseg->length);
+        set_if_smaller(b_length, keyseg->length);
+      }
+      memcpy((char**) &pos_a, pos_a+keyseg->bit_start, sizeof(char*));
+      memcpy((char**) &pos_b, pos_b+keyseg->bit_start, sizeof(char*));
+    }
+    if (type == HA_KEYTYPE_TEXT/*The CHAR data type*/)
+    {
+      if (ha_compare_char_fixed(keyseg->charset,
+                                (uchar *) pos_a, a_length,
+                                (uchar *) pos_b, b_length,
+                                keyseg->length / keyseg->charset->mbmaxlen,
+                                FALSE/*b_is_prefix*/))
+        return 1;
+    }
+    else if (type == HA_KEYTYPE_VARTEXT1 ||
+             type == HA_KEYTYPE_VARTEXT2)
+    {
+      if (ha_compare_char_varying(keyseg->charset,
+                                  (uchar *) pos_a, a_length,
+                                  (uchar *) pos_b, b_length,
+                                  FALSE/*b_is_prefix*/))
+        return 1;
+    }
+    else
+    {
+      if (a_length != b_length)
+        return 1;
+      end= pos_a+a_length;
+      while (pos_a != end)
+      {
+	if (*pos_a++ != *pos_b++)
+	  return 1;
+      }
+    }
+  }
+  return 0;
+}