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, 1733 insertions, 0 deletions

diff --git a/storage/maria/ma_packrec.c b/storage/maria/ma_packrec.c
new file mode 100644
index 00000000..19783423
--- /dev/null
+++ b/storage/maria/ma_packrec.c
@@ -0,0 +1,1733 @@
+/* Copyright (C) 2006 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
+   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 Street, Fifth Floor, Boston, MA 02110-1335 USA */
+
+	/* Functions to compressed records */
+
+#include "maria_def.h"
+
+#define IS_CHAR ((uint) 32768)		/* Bit if char (not offset) in tree */
+
+/* Some definitions to keep in sync with maria_pack.c */
+#define HEAD_LENGTH	32              /* Length of fixed header */
+
+#if INT_MAX > 32767
+#define BITS_SAVED 32
+#define MAX_QUICK_TABLE_BITS 9		/* Because we may shift in 24 bits */
+#else
+#define BITS_SAVED 16
+#define MAX_QUICK_TABLE_BITS 6
+#endif
+
+#define get_bit(BU) ((BU)->bits ? \
+		     (BU)->current_byte & ((maria_bit_type) 1 << --(BU)->bits) :\
+		     (fill_buffer(BU), (BU)->bits= BITS_SAVED-1,\
+		      (BU)->current_byte & ((maria_bit_type) 1 << (BITS_SAVED-1))))
+#define skip_to_next_byte(BU) ((BU)->bits&=~7)
+#define get_bits(BU,count) (((BU)->bits >= count) ? (((BU)->current_byte >> ((BU)->bits-=count)) & mask[count]) : fill_and_get_bits(BU,count))
+
+#define decode_bytes_test_bit(bit) \
+  if (low_byte & (1 << (7-bit))) \
+    pos++; \
+  if (*pos & IS_CHAR) \
+  { bits-=(bit+1); break; } \
+  pos+= *pos
+
+/*
+  Size in uint16 of a Huffman tree for uchar compression of 256 uchar values
+*/
+#define OFFSET_TABLE_SIZE 512
+
+static my_bool _ma_read_pack_info(MARIA_SHARE *share, File file,
+                                  pbool fix_keys);
+static uint read_huff_table(MARIA_BIT_BUFF *bit_buff,
+                            MARIA_DECODE_TREE *decode_tree,
+			    uint16 **decode_table,uchar **intervall_buff,
+			    uint16 *tmp_buff);
+static void make_quick_table(uint16 *to_table,uint16 *decode_table,
+			     uint *next_free,uint value,uint bits,
+			     uint max_bits);
+static void fill_quick_table(uint16 *table,uint bits, uint max_bits,
+			     uint value);
+static uint copy_decode_table(uint16 *to_pos,uint offset,
+			      uint16 *decode_table);
+static uint find_longest_bitstream(uint16 *table, uint16 *end);
+static void (*get_unpack_function(MARIA_COLUMNDEF *rec))(MARIA_COLUMNDEF *field,
+                                                         MARIA_BIT_BUFF *buff,
+                                                         uchar *to,
+                                                         uchar *end);
+static void uf_zerofill_skip_zero(MARIA_COLUMNDEF *rec,
+                                  MARIA_BIT_BUFF *bit_buff,
+                                  uchar *to,uchar *end);
+static void uf_skip_zero(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+                         uchar *to,uchar *end);
+static void uf_space_normal(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+			    uchar *to,uchar *end);
+static void uf_space_endspace_selected(MARIA_COLUMNDEF *rec,
+                                       MARIA_BIT_BUFF *bit_buff,
+				       uchar *to, uchar *end);
+static void uf_endspace_selected(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+				 uchar *to,uchar *end);
+static void uf_space_endspace(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+			      uchar *to,uchar *end);
+static void uf_endspace(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+			uchar *to,uchar *end);
+static void uf_space_prespace_selected(MARIA_COLUMNDEF *rec,
+                                       MARIA_BIT_BUFF *bit_buff,
+				       uchar *to, uchar *end);
+static void uf_prespace_selected(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+				 uchar *to,uchar *end);
+static void uf_space_prespace(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+			      uchar *to,uchar *end);
+static void uf_prespace(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+			uchar *to,uchar *end);
+static void uf_zerofill_normal(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+			       uchar *to,uchar *end);
+static void uf_constant(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+			uchar *to,uchar *end);
+static void uf_intervall(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+			 uchar *to,uchar *end);
+static void uf_zero(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+		    uchar *to,uchar *end);
+static void uf_blob(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+		    uchar *to, uchar *end);
+static void uf_varchar1(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+                        uchar *to, uchar *end);
+static void uf_varchar2(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+                        uchar *to, uchar *end);
+static void decode_bytes(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+			 uchar *to,uchar *end);
+static uint decode_pos(MARIA_BIT_BUFF *bit_buff,
+                       MARIA_DECODE_TREE *decode_tree);
+static void init_bit_buffer(MARIA_BIT_BUFF *bit_buff,uchar *buffer,
+                            uint length);
+static uint fill_and_get_bits(MARIA_BIT_BUFF *bit_buff,uint count);
+static void fill_buffer(MARIA_BIT_BUFF *bit_buff);
+static uint max_bit(uint value);
+static uint read_pack_length(uint version, const uchar *buf, ulong *length);
+#ifdef HAVE_MMAP
+static uchar *_ma_mempack_get_block_info(MARIA_HA *maria,
+                                         MARIA_BIT_BUFF *bit_buff,
+                                         MARIA_BLOCK_INFO *info,
+                                         uchar **rec_buff_p,
+                                         size_t *rec_buff_size_p,
+					 uchar *header);
+#endif
+
+static maria_bit_type mask[]=
+{
+   0x00000000,
+   0x00000001, 0x00000003, 0x00000007, 0x0000000f,
+   0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff,
+   0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff,
+   0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff,
+#if BITS_SAVED > 16
+   0x0001ffff, 0x0003ffff, 0x0007ffff, 0x000fffff,
+   0x001fffff, 0x003fffff, 0x007fffff, 0x00ffffff,
+   0x01ffffff, 0x03ffffff, 0x07ffffff, 0x0fffffff,
+   0x1fffffff, 0x3fffffff, 0x7fffffff, 0xffffffff,
+#endif
+};
+
+
+my_bool _ma_once_init_pack_row(MARIA_SHARE *share, File dfile)
+{
+  share->options|= HA_OPTION_READ_ONLY_DATA;
+  return (_ma_read_pack_info(share, dfile,
+                             (pbool)
+                             MY_TEST(!(share->options &
+                                       (HA_OPTION_PACK_RECORD |
+                                        HA_OPTION_TEMP_COMPRESS_RECORD)))));
+}
+
+
+my_bool _ma_once_end_pack_row(MARIA_SHARE *share)
+{
+  if (share->decode_trees)
+  {
+    my_free(share->decode_trees);
+    my_free(share->decode_tables);
+  }
+  return 0;
+}
+
+
+/* Read all packed info, allocate memory and fix field structs */
+
+static my_bool _ma_read_pack_info(MARIA_SHARE *share, File file,
+                                  pbool fix_keys)
+{
+  int diff_length;
+  uint i,trees,huff_tree_bits,rec_reflength,length;
+  uint16 *decode_table,*tmp_buff;
+  ulong elements,intervall_length;
+  uchar *disk_cache;
+  uchar *intervall_buff;
+  uchar header[HEAD_LENGTH];
+  MARIA_BIT_BUFF bit_buff;
+  DBUG_ENTER("_ma_read_pack_info");
+
+  if (maria_quick_table_bits < 4)
+    maria_quick_table_bits=4;
+  else if (maria_quick_table_bits > MAX_QUICK_TABLE_BITS)
+    maria_quick_table_bits=MAX_QUICK_TABLE_BITS;
+
+  my_errno=0;
+  if (mysql_file_read(file, header, sizeof(header), MYF(MY_NABP)))
+  {
+    if (!my_errno)
+      my_errno=HA_ERR_END_OF_FILE;
+    goto err0;
+  }
+  /* Only the first three bytes of magic number are independent of version. */
+  if (memcmp(header, maria_pack_file_magic, 3))
+  {
+    _ma_set_fatal_error_with_share(share, HA_ERR_WRONG_IN_RECORD);
+    goto err0;
+  }
+  share->pack.version= header[3]; /* fourth uchar of magic number */
+  share->pack.header_length=	uint4korr(header+4);
+  share->min_pack_length=(uint) uint4korr(header+8);
+  share->max_pack_length=(uint) uint4korr(header+12);
+  set_if_bigger(share->base.default_rec_buff_size,
+                share->max_pack_length + 7);
+  elements=uint4korr(header+16);
+  intervall_length=uint4korr(header+20);
+  trees=uint2korr(header+24);
+  share->pack.ref_length=header[26];
+  rec_reflength=header[27];
+  diff_length=(int) rec_reflength - (int) share->base.rec_reflength;
+  if (fix_keys)
+    share->rec_reflength=rec_reflength;
+  DBUG_PRINT("info", ("fixed header length:   %u", HEAD_LENGTH));
+  DBUG_PRINT("info", ("total header length:   %lu", share->pack.header_length));
+  DBUG_PRINT("info", ("pack file version:     %u", share->pack.version));
+  DBUG_PRINT("info", ("min pack length:       %lu", share->min_pack_length));
+  DBUG_PRINT("info", ("max pack length:       %lu", share->max_pack_length));
+  DBUG_PRINT("info", ("elements of all trees: %lu", elements));
+  DBUG_PRINT("info", ("distinct values bytes: %lu", intervall_length));
+  DBUG_PRINT("info", ("number of code trees:  %u", trees));
+  DBUG_PRINT("info", ("bytes for record lgt:  %u", share->pack.ref_length));
+  DBUG_PRINT("info", ("record pointer length: %u", rec_reflength));
+
+
+  /*
+    Memory segment #1:
+    - Decode tree heads
+    - Distinct column values
+  */
+  if (!(share->decode_trees=(MARIA_DECODE_TREE*)
+	my_malloc(PSI_INSTRUMENT_ME, (uint) (trees*sizeof(MARIA_DECODE_TREE)+
+			  intervall_length*sizeof(uchar)),
+		  MYF(MY_WME))))
+    goto err0;
+  intervall_buff=(uchar*) (share->decode_trees+trees);
+
+  /*
+    Memory segment #2:
+    - Decode tables
+    - Quick decode tables
+    - Temporary decode table
+    - Compressed data file header cache
+    This segment will be reallocated after construction of the tables.
+  */
+  length=(uint) (elements*2+trees*(1 << maria_quick_table_bits));
+  if (!(share->decode_tables=(uint16*)
+	my_malloc(PSI_INSTRUMENT_ME, (length+OFFSET_TABLE_SIZE)*sizeof(uint16)+
+		  (uint) (share->pack.header_length - sizeof(header)) +
+                  share->base.extra_rec_buff_size,
+		  MYF(MY_WME | MY_ZEROFILL))))
+    goto err1;
+  tmp_buff=share->decode_tables+length;
+  disk_cache=(uchar*) (tmp_buff+OFFSET_TABLE_SIZE);
+
+  if (mysql_file_read(file,disk_cache,
+	      (uint) (share->pack.header_length-sizeof(header)),
+	      MYF(MY_NABP)))
+    goto err2;
+#ifdef HAVE_valgrind
+  /* Zero bytes accessed by fill_buffer */
+  bzero(disk_cache + (share->pack.header_length-sizeof(header)),
+        share->base.extra_rec_buff_size);
+#endif
+
+  huff_tree_bits=max_bit(trees ? trees-1 : 0);
+  init_bit_buffer(&bit_buff, disk_cache,
+		  (uint) (share->pack.header_length-sizeof(header)));
+	/* Read new info for each field */
+  for (i=0 ; i < share->base.fields ; i++)
+  {
+    share->columndef[i].base_type=(enum en_fieldtype) get_bits(&bit_buff,5);
+    share->columndef[i].pack_type=(uint) get_bits(&bit_buff,6);
+    share->columndef[i].space_length_bits=get_bits(&bit_buff,5);
+    share->columndef[i].huff_tree=share->decode_trees+(uint) get_bits(&bit_buff,
+								huff_tree_bits);
+    share->columndef[i].unpack= get_unpack_function(share->columndef + i);
+    DBUG_PRINT("info", ("col: %2u  type: %2u  pack: %u  slbits: %2u",
+                        i, share->columndef[i].base_type,
+                        share->columndef[i].pack_type,
+                        share->columndef[i].space_length_bits));
+  }
+  skip_to_next_byte(&bit_buff);
+  /*
+    Construct the decoding tables from the file header. Keep track of
+    the used memory.
+  */
+  decode_table=share->decode_tables;
+  for (i=0 ; i < trees ; i++)
+    if (read_huff_table(&bit_buff,share->decode_trees+i,&decode_table,
+                        &intervall_buff,tmp_buff))
+      goto err3;
+  /* Reallocate the decoding tables to the used size. */
+  decode_table=(uint16*)
+    my_realloc(PSI_INSTRUMENT_ME, (uchar*) share->decode_tables,
+	       (uint) ((uchar*) decode_table - (uchar*) share->decode_tables),
+	       MYF(0));
+  /* Fix the table addresses in the tree heads. */
+  {
+    my_ptrdiff_t diff= PTR_BYTE_DIFF(decode_table,share->decode_tables);
+    share->decode_tables=decode_table;
+    for (i=0 ; i < trees ; i++)
+      share->decode_trees[i].table=ADD_TO_PTR(share->decode_trees[i].table,
+                                              diff, uint16*);
+  }
+
+	/* Fix record-ref-length for keys */
+  if (fix_keys)
+  {
+    for (i=0 ; i < share->base.keys ; i++)
+    {
+      MARIA_KEYDEF *keyinfo= &share->keyinfo[i];
+      keyinfo->keylength+= (uint16) diff_length;
+      keyinfo->minlength+= (uint16) diff_length;
+      keyinfo->maxlength+= (uint16) diff_length;
+      keyinfo->seg[keyinfo->flag & HA_FULLTEXT ?
+                   FT_SEGS : keyinfo->keysegs].length= (uint16) rec_reflength;
+    }
+    if (share->ft2_keyinfo.seg)
+    {
+      MARIA_KEYDEF *ft2_keyinfo= &share->ft2_keyinfo;
+      ft2_keyinfo->keylength+= (uint16) diff_length;
+      ft2_keyinfo->minlength+= (uint16) diff_length;
+      ft2_keyinfo->maxlength+= (uint16) diff_length;
+    }
+  }
+
+  if (bit_buff.error || bit_buff.pos < bit_buff.end)
+    goto err3;
+
+  DBUG_RETURN(0);
+
+err3:
+  _ma_set_fatal_error_with_share(share, HA_ERR_WRONG_IN_RECORD);
+err2:
+  my_free(share->decode_tables);
+err1:
+  my_free(share->decode_trees);
+err0:
+  DBUG_RETURN(1);
+}
+
+
+/*
+  Read a huff-code-table from datafile.
+
+  SYNOPSIS
+    read_huff_table()
+      bit_buff                  Bit buffer pointing at start of the
+                                decoding table in the file header cache.
+      decode_tree               Pointer to the decode tree head.
+      decode_table      IN/OUT  Address of a pointer to the next free space.
+      intervall_buff    IN/OUT  Address of a pointer to the next unused values.
+      tmp_buff                  Buffer for temporary extraction of a full
+                                decoding table as read from bit_buff.
+
+  RETURN
+    0           OK.
+    1           Error.
+*/
+static uint read_huff_table(MARIA_BIT_BUFF *bit_buff,
+                            MARIA_DECODE_TREE *decode_tree,
+			    uint16 **decode_table, uchar **intervall_buff,
+			    uint16 *tmp_buff)
+{
+  uint min_chr,elements,char_bits,offset_bits,size,intervall_length,table_bits,
+  next_free_offset;
+  uint16 *ptr,*end;
+  DBUG_ENTER("read_huff_table");
+
+  if (!get_bits(bit_buff,1))
+  {
+    /* Byte value compression. */
+    min_chr=get_bits(bit_buff,8);
+    elements=get_bits(bit_buff,9);
+    char_bits=get_bits(bit_buff,5);
+    offset_bits=get_bits(bit_buff,5);
+    intervall_length=0;
+    ptr=tmp_buff;
+    ptr=tmp_buff;
+    DBUG_PRINT("info", ("byte value compression"));
+    DBUG_PRINT("info", ("minimum uchar value:    %u", min_chr));
+    DBUG_PRINT("info", ("number of tree nodes:  %u", elements));
+    DBUG_PRINT("info", ("bits for values:       %u", char_bits));
+    DBUG_PRINT("info", ("bits for tree offsets: %u", offset_bits));
+    if (elements > 256)
+    {
+      DBUG_PRINT("error", ("ERROR: illegal number of tree elements: %u",
+                           elements));
+      DBUG_RETURN(1);
+    }
+  }
+  else
+  {
+    /* Distinct column value compression. */
+    min_chr=0;
+    elements=get_bits(bit_buff,15);
+    intervall_length=get_bits(bit_buff,16);
+    char_bits=get_bits(bit_buff,5);
+    offset_bits=get_bits(bit_buff,5);
+    decode_tree->quick_table_bits=0;
+    ptr= *decode_table;
+    DBUG_PRINT("info", ("distinct column value compression"));
+    DBUG_PRINT("info", ("number of tree nodes:  %u", elements));
+    DBUG_PRINT("info", ("value buffer length:   %u", intervall_length));
+    DBUG_PRINT("info", ("bits for value index:  %u", char_bits));
+    DBUG_PRINT("info", ("bits for tree offsets: %u", offset_bits));
+  }
+  size=elements*2-2;
+  DBUG_PRINT("info", ("tree size in uint16:   %u", size));
+  DBUG_PRINT("info", ("tree size in bytes:    %u",
+                      size * (uint) sizeof(uint16)));
+
+  for (end=ptr+size ; ptr < end ; ptr++)
+  {
+    if (get_bit(bit_buff))
+    {
+      *ptr= (uint16) get_bits(bit_buff,offset_bits);
+      if ((ptr + *ptr >= end) || !*ptr)
+      {
+        DBUG_PRINT("error", ("ERROR: illegal pointer in decode tree"));
+        DBUG_RETURN(1);
+      }
+    }
+    else
+      *ptr= (uint16) (IS_CHAR + (get_bits(bit_buff,char_bits) + min_chr));
+  }
+  skip_to_next_byte(bit_buff);
+
+  decode_tree->table= *decode_table;
+  decode_tree->intervalls= *intervall_buff;
+  if (! intervall_length)
+  {
+    /* Byte value compression. ptr started from tmp_buff. */
+    /* Find longest Huffman code from begin to end of tree in bits. */
+    table_bits= find_longest_bitstream(tmp_buff, ptr);
+    if (table_bits >= OFFSET_TABLE_SIZE)
+      DBUG_RETURN(1);
+    if (table_bits > maria_quick_table_bits)
+      table_bits=maria_quick_table_bits;
+    DBUG_PRINT("info", ("table bits:            %u", table_bits));
+
+    next_free_offset= (1 << table_bits);
+    make_quick_table(*decode_table,tmp_buff,&next_free_offset,0,table_bits,
+		     table_bits);
+    (*decode_table)+= next_free_offset;
+    decode_tree->quick_table_bits=table_bits;
+  }
+  else
+  {
+    /* Distinct column value compression. ptr started from *decode_table */
+    (*decode_table)=end;
+    /*
+      get_bits() moves some bytes to a cache buffer in advance. May need
+      to step back.
+    */
+    bit_buff->pos-= bit_buff->bits/8;
+    /* Copy the distinct column values from the buffer. */
+    memcpy(*intervall_buff,bit_buff->pos,(size_t) intervall_length);
+    (*intervall_buff)+=intervall_length;
+    bit_buff->pos+=intervall_length;
+    bit_buff->bits=0;
+  }
+  DBUG_RETURN(0);
+}
+
+
+/*
+  Make a quick_table for faster decoding.
+
+  SYNOPSIS
+    make_quick_table()
+      to_table                  Target quick_table and remaining decode table.
+      decode_table              Source Huffman (sub-)tree within tmp_buff.
+      next_free_offset   IN/OUT Next free offset from to_table.
+                                Starts behind quick_table on the top-level.
+      value                     Huffman bits found so far.
+      bits                      Remaining bits to be collected.
+      max_bits                  Total number of bits to collect (table_bits).
+
+  DESCRIPTION
+
+    The quick table is an array of 16-bit values. There exists one value
+    for each possible code representable by max_bits (table_bits) bits.
+    In most cases table_bits is 9. So there are 512 16-bit values.
+
+    If the high-order bit (16) is set (IS_CHAR) then the array slot for
+    this value is a valid Huffman code for a resulting uchar value.
+
+    The low-order 8 bits (1..8) are the resulting uchar value.
+
+    Bits 9..14 are the length of the Huffman code for this uchar value.
+    This means so many bits from the input stream were needed to
+    represent this uchar value. The remaining bits belong to later
+    Huffman codes. This also means that for every Huffman code shorter
+    than table_bits there are multiple entires in the array, which
+    differ just in the unused bits.
+
+    If the high-order bit (16) is clear (0) then the remaining bits are
+    the position of the remaining Huffman decode tree segment behind the
+    quick table.
+
+  RETURN
+    void
+*/
+
+static void make_quick_table(uint16 *to_table, uint16 *decode_table,
+			     uint *next_free_offset, uint value, uint bits,
+			     uint max_bits)
+{
+  DBUG_ENTER("make_quick_table");
+
+  /*
+    When down the table to the requested maximum, copy the rest of the
+    Huffman table.
+  */
+  if (!bits--)
+  {
+    /*
+      Remaining left  Huffman tree segment starts behind quick table.
+      Remaining right Huffman tree segment starts behind left segment.
+    */
+    to_table[value]= (uint16) *next_free_offset;
+    /*
+      Re-construct the remaining Huffman tree segment at
+      next_free_offset in to_table.
+    */
+    *next_free_offset=copy_decode_table(to_table, *next_free_offset,
+					decode_table);
+    DBUG_VOID_RETURN;
+  }
+
+  /* Descent on the left side. Left side bits are clear (0). */
+  if (!(*decode_table & IS_CHAR))
+  {
+    /* Not a leaf. Follow the pointer. */
+    make_quick_table(to_table,decode_table+ *decode_table,
+		     next_free_offset,value,bits,max_bits);
+  }
+  else
+  {
+    /*
+      A leaf. A Huffman code is complete. Fill the quick_table
+      array for all possible bit strings starting with this Huffman
+      code.
+    */
+    fill_quick_table(to_table+value,bits,max_bits,(uint) *decode_table);
+  }
+
+  /* Descent on the right side. Right side bits are set (1). */
+  decode_table++;
+  value|= (1 << bits);
+  if (!(*decode_table & IS_CHAR))
+  {
+    /* Not a leaf. Follow the pointer. */
+    make_quick_table(to_table,decode_table+ *decode_table,
+		     next_free_offset,value,bits,max_bits);
+  }
+  else
+  {
+    /*
+      A leaf. A Huffman code is complete. Fill the quick_table
+      array for all possible bit strings starting with this Huffman
+      code.
+    */
+    fill_quick_table(to_table+value,bits,max_bits,(uint) *decode_table);
+  }
+
+  DBUG_VOID_RETURN;
+}
+
+
+/*
+  Fill quick_table for all possible values starting with this Huffman code.
+
+  SYNOPSIS
+    fill_quick_table()
+      table                     Target quick_table position.
+      bits                      Unused bits from max_bits.
+      max_bits                  Total number of bits to collect (table_bits).
+      value                     The uchar encoded by the found Huffman code.
+
+  DESCRIPTION
+
+    Fill the segment (all slots) of the quick_table array with the
+    resulting value for the found Huffman code. There are as many slots
+    as there are combinations representable by the unused bits.
+
+    In most cases we use 9 table bits. Assume a 3-bit Huffman code. Then
+    there are 6 unused bits. Hence we fill 2**6 = 64 slots with the
+    value.
+
+  RETURN
+    void
+*/
+
+static void fill_quick_table(uint16 *table, uint bits, uint max_bits,
+			     uint value)
+{
+  uint16 *end;
+  DBUG_ENTER("fill_quick_table");
+
+  /*
+    Bits 1..8 of value represent the decoded uchar value.
+    Bits 9..14 become the length of the Huffman code for this uchar value.
+    Bit 16 flags a valid code (IS_CHAR).
+  */
+  value|= (max_bits - bits) << 8 | IS_CHAR;
+
+  for (end= table + ((my_ptrdiff_t) 1 << bits); table < end; table++)
+  {
+    *table= (uint16) value;
+  }
+  DBUG_VOID_RETURN;
+}
+
+
+/*
+  Reconstruct a decode subtree at the target position.
+
+  SYNOPSIS
+    copy_decode_table()
+      to_pos                    Target quick_table and remaining decode table.
+      offset                    Next free offset from to_pos.
+      decode_table              Source Huffman subtree within tmp_buff.
+
+  NOTE
+    Pointers in the decode tree are relative to the pointers position.
+
+  RETURN
+    next free offset from to_pos.
+*/
+
+static uint copy_decode_table(uint16 *to_pos, uint offset,
+			      uint16 *decode_table)
+{
+  uint prev_offset= offset;
+  DBUG_ENTER("copy_decode_table");
+
+  /* Descent on the left side. */
+  if (!(*decode_table & IS_CHAR))
+  {
+    /* Set a pointer to the next target node. */
+    to_pos[offset]=2;
+    /* Copy the left hand subtree there. */
+    offset=copy_decode_table(to_pos,offset+2,decode_table+ *decode_table);
+  }
+  else
+  {
+    /* Copy the uchar value. */
+    to_pos[offset]= *decode_table;
+    /* Step behind this node. */
+    offset+=2;
+  }
+
+  /* Descent on the right side. */
+  decode_table++;
+  if (!(*decode_table & IS_CHAR))
+  {
+    /* Set a pointer to the next free target node. */
+    to_pos[prev_offset+1]=(uint16) (offset-prev_offset-1);
+    /* Copy the right hand subtree to the entry of that node. */
+    offset=copy_decode_table(to_pos,offset,decode_table+ *decode_table);
+  }
+  else
+  {
+    /* Copy the uchar value. */
+    to_pos[prev_offset+1]= *decode_table;
+  }
+  DBUG_RETURN(offset);
+}
+
+
+/*
+  Find the length of the longest Huffman code in this table in bits.
+
+  SYNOPSIS
+    find_longest_bitstream()
+      table                     Code (sub-)table start.
+      end                       End of code table.
+
+  IMPLEMENTATION
+
+    Recursively follow the branch(es) of the code pair on every level of
+    the tree until two uchar values (and no branch) are found. Add one to
+    each level when returning back from each recursion stage.
+
+    'end' is used for error checking only. A clean tree terminates
+    before reaching 'end'. Hence the exact value of 'end' is not too
+    important. However having it higher than necessary could lead to
+    misbehaviour should 'next' jump into the dirty area.
+
+  RETURN
+    length                  Length of longest Huffman code in bits.
+    >= OFFSET_TABLE_SIZE    Error, broken tree. It does not end before 'end'.
+*/
+
+static uint find_longest_bitstream(uint16 *table, uint16 *end)
+{
+  uint length=1;
+  uint length2;
+  if (!(*table & IS_CHAR))
+  {
+    uint16 *next= table + *table;
+    if (next > end || next == table)
+    {
+      DBUG_PRINT("error", ("ERROR: illegal pointer in decode tree"));
+      return OFFSET_TABLE_SIZE;
+    }
+    length=find_longest_bitstream(next, end)+1;
+  }
+  table++;
+  if (!(*table & IS_CHAR))
+  {
+    uint16 *next= table + *table;
+    if (next > end || next == table)
+    {
+      DBUG_PRINT("error", ("ERROR: illegal pointer in decode tree"));
+      return OFFSET_TABLE_SIZE;
+    }
+    length2= find_longest_bitstream(next, end) + 1;
+    length=MY_MAX(length,length2);
+  }
+  return length;
+}
+
+
+/*
+  Read record from datafile.
+
+  SYNOPSIS
+    _ma_read_pack_record()
+    info                        A pointer to MARIA_HA.
+    filepos                     File offset of the record.
+    buf                 RETURN  The buffer to receive the record.
+
+  RETURN
+    0   On success
+    #   Error number
+*/
+
+int _ma_read_pack_record(MARIA_HA *info, uchar *buf, MARIA_RECORD_POS filepos)
+{
+  MARIA_BLOCK_INFO block_info;
+  File file;
+  DBUG_ENTER("maria_read_pack_record");
+
+  if (filepos == HA_OFFSET_ERROR)
+    DBUG_RETURN(my_errno);          /* _search() didn't find record */
+
+  file= info->dfile.file;
+  if (_ma_pack_get_block_info(info, &info->bit_buff, &block_info,
+                              &info->rec_buff, &info->rec_buff_size, file,
+                              filepos))
+    goto err;
+  if (mysql_file_read(file, info->rec_buff + block_info.offset ,
+	      block_info.rec_len - block_info.offset, MYF(MY_NABP)))
+    goto panic;
+  info->update|= HA_STATE_AKTIV;
+
+  info->rec_buff[block_info.rec_len]= 0; /* Keep valgrind happy */
+  DBUG_RETURN(_ma_pack_rec_unpack(info,&info->bit_buff, buf,
+                                  info->rec_buff, block_info.rec_len));
+panic:
+  _ma_set_fatal_error(info, HA_ERR_WRONG_IN_RECORD);
+err:
+  DBUG_RETURN(my_errno);
+}
+
+
+
+int _ma_pack_rec_unpack(register MARIA_HA *info, MARIA_BIT_BUFF *bit_buff,
+                        register uchar *to, uchar *from, ulong reclength)
+{
+  uchar *end_field;
+  reg3 MARIA_COLUMNDEF *end;
+  MARIA_COLUMNDEF *current_field;
+  MARIA_SHARE *share= info->s;
+  DBUG_ENTER("_ma_pack_rec_unpack");
+
+  if (info->s->base.null_bytes)
+  {
+    memcpy(to, from, info->s->base.null_bytes);
+    to+=   info->s->base.null_bytes;
+    from+= info->s->base.null_bytes;
+    reclength-= info->s->base.null_bytes;
+  }
+  init_bit_buffer(bit_buff, from, reclength);
+  for (current_field=share->columndef, end=current_field+share->base.fields ;
+       current_field < end ;
+       current_field++,to=end_field)
+  {
+    end_field=to+current_field->length;
+    (*current_field->unpack)(current_field, bit_buff, to, end_field);
+  }
+  if (!bit_buff->error &&
+      bit_buff->pos - bit_buff->bits / 8 == bit_buff->end)
+    DBUG_RETURN(0);
+  info->update&= ~HA_STATE_AKTIV;
+  _ma_set_fatal_error(info, HA_ERR_WRONG_IN_RECORD);
+  DBUG_RETURN(HA_ERR_WRONG_IN_RECORD);
+} /* _ma_pack_rec_unpack */
+
+
+	/* Return function to unpack field */
+
+static void (*get_unpack_function(MARIA_COLUMNDEF *rec))
+  (MARIA_COLUMNDEF *, MARIA_BIT_BUFF *, uchar *, uchar *)
+{
+  switch (rec->base_type) {
+  case FIELD_SKIP_ZERO:
+    if (rec->pack_type & PACK_TYPE_ZERO_FILL)
+      return &uf_zerofill_skip_zero;
+    return &uf_skip_zero;
+  case FIELD_NORMAL:
+    if (rec->pack_type & PACK_TYPE_SPACE_FIELDS)
+      return &uf_space_normal;
+    if (rec->pack_type & PACK_TYPE_ZERO_FILL)
+      return &uf_zerofill_normal;
+    return &decode_bytes;
+  case FIELD_SKIP_ENDSPACE:
+    if (rec->pack_type & PACK_TYPE_SPACE_FIELDS)
+    {
+      if (rec->pack_type & PACK_TYPE_SELECTED)
+	return &uf_space_endspace_selected;
+      return &uf_space_endspace;
+    }
+    if (rec->pack_type & PACK_TYPE_SELECTED)
+      return &uf_endspace_selected;
+    return &uf_endspace;
+  case FIELD_SKIP_PRESPACE:
+    if (rec->pack_type & PACK_TYPE_SPACE_FIELDS)
+    {
+      if (rec->pack_type & PACK_TYPE_SELECTED)
+	return &uf_space_prespace_selected;
+      return &uf_space_prespace;
+    }
+    if (rec->pack_type & PACK_TYPE_SELECTED)
+      return &uf_prespace_selected;
+    return &uf_prespace;
+  case FIELD_CONSTANT:
+    return &uf_constant;
+  case FIELD_INTERVALL:
+    return &uf_intervall;
+  case FIELD_ZERO:
+  case FIELD_CHECK:
+    return &uf_zero;
+  case FIELD_BLOB:
+    return &uf_blob;
+  case FIELD_VARCHAR:
+    if (rec->length <= 256)                      /* 255 + 1 uchar length */
+      return &uf_varchar1;
+    return &uf_varchar2;
+  case FIELD_LAST:
+  default:
+    return 0;			/* This should never happend */
+  }
+}
+
+	/* The different functions to unpack a field */
+
+static void uf_zerofill_skip_zero(MARIA_COLUMNDEF *rec,
+                                  MARIA_BIT_BUFF *bit_buff,
+                                  uchar *to, uchar *end)
+{
+  if (get_bit(bit_buff))
+    bzero((char*) to,(uint) (end-to));
+  else
+  {
+    end-=rec->space_length_bits;
+    decode_bytes(rec,bit_buff,to,end);
+    bzero((char*) end,rec->space_length_bits);
+  }
+}
+
+static void uf_skip_zero(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+                         uchar *to, uchar *end)
+{
+  if (get_bit(bit_buff))
+    bzero((char*) to,(uint) (end-to));
+  else
+    decode_bytes(rec,bit_buff,to,end);
+}
+
+static void uf_space_normal(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+                            uchar *to, uchar *end)
+{
+  if (get_bit(bit_buff))
+    bfill(to, (end-to), ' ');
+  else
+    decode_bytes(rec,bit_buff,to,end);
+}
+
+static void uf_space_endspace_selected(MARIA_COLUMNDEF *rec,
+                                       MARIA_BIT_BUFF *bit_buff,
+				       uchar *to, uchar *end)
+{
+  uint spaces;
+  if (get_bit(bit_buff))
+    bfill(to, (end-to), ' ');
+  else
+  {
+    if (get_bit(bit_buff))
+    {
+      if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
+      {
+	bit_buff->error=1;
+	return;
+      }
+      if (to+spaces != end)
+	decode_bytes(rec,bit_buff,to,end-spaces);
+      bfill(end - spaces, spaces, ' ');
+    }
+    else
+      decode_bytes(rec,bit_buff,to,end);
+  }
+}
+
+static void uf_endspace_selected(MARIA_COLUMNDEF *rec,
+                                 MARIA_BIT_BUFF *bit_buff,
+				 uchar *to, uchar *end)
+{
+  uint spaces;
+  if (get_bit(bit_buff))
+  {
+    if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
+    {
+      bit_buff->error=1;
+      return;
+    }
+    if (to+spaces != end)
+      decode_bytes(rec,bit_buff,to,end-spaces);
+    bfill(end - spaces, spaces, ' ');
+  }
+  else
+    decode_bytes(rec,bit_buff,to,end);
+}
+
+static void uf_space_endspace(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+                              uchar *to, uchar *end)
+{
+  uint spaces;
+  if (get_bit(bit_buff))
+    bfill(to, (end-to), ' ');
+  else
+  {
+    if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
+    {
+      bit_buff->error=1;
+      return;
+    }
+    if (to+spaces != end)
+      decode_bytes(rec,bit_buff,to,end-spaces);
+    bfill(end - spaces, spaces, ' ');
+  }
+}
+
+static void uf_endspace(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+                        uchar *to, uchar *end)
+{
+  uint spaces;
+  if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
+  {
+    bit_buff->error=1;
+    return;
+  }
+  if (to+spaces != end)
+    decode_bytes(rec,bit_buff,to,end-spaces);
+  bfill(end - spaces, spaces, ' ');
+}
+
+static void uf_space_prespace_selected(MARIA_COLUMNDEF *rec,
+                                       MARIA_BIT_BUFF *bit_buff,
+				       uchar *to, uchar *end)
+{
+  uint spaces;
+  if (get_bit(bit_buff))
+    bfill(to, (end-to), ' ');
+  else
+  {
+    if (get_bit(bit_buff))
+    {
+      if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
+      {
+	bit_buff->error=1;
+	return;
+      }
+      bfill(to, spaces, ' ');
+      if (to+spaces != end)
+	decode_bytes(rec,bit_buff,to+spaces,end);
+    }
+    else
+      decode_bytes(rec,bit_buff,to,end);
+  }
+}
+
+
+static void uf_prespace_selected(MARIA_COLUMNDEF *rec,
+                                 MARIA_BIT_BUFF *bit_buff,
+				 uchar *to, uchar *end)
+{
+  uint spaces;
+  if (get_bit(bit_buff))
+  {
+    if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
+    {
+      bit_buff->error=1;
+      return;
+    }
+    bfill(to, spaces, ' ');
+    if (to+spaces != end)
+      decode_bytes(rec,bit_buff,to+spaces,end);
+  }
+  else
+    decode_bytes(rec,bit_buff,to,end);
+}
+
+
+static void uf_space_prespace(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+                              uchar *to, uchar *end)
+{
+  uint spaces;
+  if (get_bit(bit_buff))
+    bfill(to, (end-to), ' ');
+  else
+  {
+    if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
+    {
+      bit_buff->error=1;
+      return;
+    }
+    bfill(to, spaces, ' ');
+    if (to+spaces != end)
+      decode_bytes(rec,bit_buff,to+spaces,end);
+  }
+}
+
+static void uf_prespace(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+                        uchar *to, uchar *end)
+{
+  uint spaces;
+  if ((spaces=get_bits(bit_buff,rec->space_length_bits))+to > end)
+  {
+    bit_buff->error=1;
+    return;
+  }
+  bfill(to, spaces, ' ');
+  if (to+spaces != end)
+    decode_bytes(rec,bit_buff,to+spaces,end);
+}
+
+static void uf_zerofill_normal(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+                               uchar *to, uchar *end)
+{
+  end-=rec->space_length_bits;
+  decode_bytes(rec,bit_buff, to, end);
+  bzero((char*) end,rec->space_length_bits);
+}
+
+static void uf_constant(MARIA_COLUMNDEF *rec,
+			MARIA_BIT_BUFF *bit_buff __attribute__((unused)),
+			uchar *to, uchar *end)
+{
+  memcpy(to,rec->huff_tree->intervalls,(size_t) (end-to));
+}
+
+static void uf_intervall(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+                         uchar *to,
+			 uchar *end)
+{
+  reg1 uint field_length=(uint) (end-to);
+  memcpy(to,rec->huff_tree->intervalls+field_length*decode_pos(bit_buff,
+							       rec->huff_tree),
+	 (size_t) field_length);
+}
+
+
+/*ARGSUSED*/
+static void uf_zero(MARIA_COLUMNDEF *rec __attribute__((unused)),
+		    MARIA_BIT_BUFF *bit_buff __attribute__((unused)),
+		    uchar *to, uchar *end)
+{
+  bzero(to, (uint) (end-to));
+}
+
+static void uf_blob(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+		    uchar *to, uchar *end)
+{
+  if (get_bit(bit_buff))
+    bzero(to, (uint) (end-to));
+  else
+  {
+    ulong length=get_bits(bit_buff,rec->space_length_bits);
+    uint pack_length=(uint) (end-to)-portable_sizeof_char_ptr;
+    if (bit_buff->blob_pos+length > bit_buff->blob_end)
+    {
+      bit_buff->error=1;
+      bzero(to, (end-to));
+      return;
+    }
+    decode_bytes(rec, bit_buff, bit_buff->blob_pos,
+                 bit_buff->blob_pos + length);
+    _ma_store_blob_length(to, pack_length, length);
+    memcpy(to+pack_length, &bit_buff->blob_pos, sizeof(uchar*));
+    bit_buff->blob_pos+=length;
+  }
+}
+
+
+static void uf_varchar1(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+		       uchar *to, uchar *end __attribute__((unused)))
+{
+  if (get_bit(bit_buff))
+    to[0]= 0;				/* Zero lengths */
+  else
+  {
+    ulong length=get_bits(bit_buff,rec->space_length_bits);
+    *to= (char) length;
+    decode_bytes(rec,bit_buff,to+1,to+1+length);
+  }
+}
+
+
+static void uf_varchar2(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+		       uchar *to, uchar *end __attribute__((unused)))
+{
+  if (get_bit(bit_buff))
+    to[0]=to[1]=0;				/* Zero lengths */
+  else
+  {
+    ulong length=get_bits(bit_buff,rec->space_length_bits);
+    int2store(to,length);
+    decode_bytes(rec,bit_buff,to+2,to+2+length);
+  }
+}
+
+	/* Functions to decode of buffer of bits */
+
+#if BITS_SAVED == 64
+
+static void decode_bytes(MARIA_COLUMNDEF *rec,MARIA_BIT_BUFF *bit_buff,
+                         uchar *to, uchar *end)
+{
+  reg1 uint bits,low_byte;
+  reg3 uint16 *pos;
+  reg4 uint table_bits,table_and;
+  MARIA_DECODE_TREE *decode_tree;
+
+  decode_tree=rec->decode_tree;
+  bits=bit_buff->bits;			/* Save in reg for quicker access */
+  table_bits=decode_tree->quick_table_bits;
+  table_and= (1 << table_bits)-1;
+
+  do
+  {
+    if (bits <= 32)
+    {
+      if (bit_buff->pos > bit_buff->end+4)
+      {
+	bit_buff->error=1;
+	return;				/* Can't be right */
+      }
+      bit_buff->current_byte= (bit_buff->current_byte << 32) |
+	((((uint) bit_buff->pos[3])) |
+	 (((uint) bit_buff->pos[2]) << 8) |
+	 (((uint) bit_buff->pos[1]) << 16) |
+	 (((uint) bit_buff->pos[0]) << 24));
+      bit_buff->pos+=4;
+      bits+=32;
+    }
+    /*
+      First use info in quick_table.
+
+      The quick table is an array of 16-bit values. There exists one
+      value for each possible code representable by table_bits bits.
+      In most cases table_bits is 9. So there are 512 16-bit values.
+
+      If the high-order bit (16) is set (IS_CHAR) then the array slot
+      for this value is a valid Huffman code for a resulting uchar value.
+
+      The low-order 8 bits (1..8) are the resulting uchar value.
+
+      Bits 9..14 are the length of the Huffman code for this uchar value.
+      This means so many bits from the input stream were needed to
+      represent this uchar value. The remaining bits belong to later
+      Huffman codes. This also means that for every Huffman code shorter
+      than table_bits there are multiple entires in the array, which
+      differ just in the unused bits.
+
+      If the high-order bit (16) is clear (0) then the remaining bits are
+      the position of the remaining Huffman decode tree segment behind the
+      quick table.
+    */
+    low_byte=(uint) (bit_buff->current_byte >> (bits - table_bits)) & table_and;
+    low_byte=decode_tree->table[low_byte];
+    if (low_byte & IS_CHAR)
+    {
+      /*
+        All Huffman codes of less or equal table_bits length are in the
+        quick table. This is one of them.
+      */
+      *to++ = (char) (low_byte & 255);		/* Found char in quick table */
+      bits-=  ((low_byte >> 8) & 31);	/* Remove bits used */
+    }
+    else
+    {					/* Map through rest of decode-table */
+      /* This means that the Huffman code must be longer than table_bits. */
+      pos=decode_tree->table+low_byte;
+      bits-=table_bits;
+      /* NOTE: decode_bytes_test_bit() is a macro which contains a break !!! */
+      for (;;)
+      {
+	low_byte=(uint) (bit_buff->current_byte >> (bits-8));
+	decode_bytes_test_bit(0);
+	decode_bytes_test_bit(1);
+	decode_bytes_test_bit(2);
+	decode_bytes_test_bit(3);
+	decode_bytes_test_bit(4);
+	decode_bytes_test_bit(5);
+	decode_bytes_test_bit(6);
+	decode_bytes_test_bit(7);
+	bits-=8;
+      }
+      *to++ = (char) *pos;
+    }
+  } while (to != end);
+
+  bit_buff->bits=bits;
+  return;
+}
+
+#else
+
+static void decode_bytes(MARIA_COLUMNDEF *rec, MARIA_BIT_BUFF *bit_buff,
+                         uchar *to, uchar *end)
+{
+  reg1 uint bits,low_byte;
+  reg3 uint16 *pos;
+  reg4 uint table_bits,table_and;
+  MARIA_DECODE_TREE *decode_tree;
+
+  decode_tree=rec->huff_tree;
+  bits=bit_buff->bits;			/* Save in reg for quicker access */
+  table_bits=decode_tree->quick_table_bits;
+  table_and= (1 << table_bits)-1;
+
+  do
+  {
+    if (bits < table_bits)
+    {
+      if (bit_buff->pos > bit_buff->end+1)
+      {
+	bit_buff->error=1;
+	return;				/* Can't be right */
+      }
+#if BITS_SAVED == 32
+      bit_buff->current_byte= (bit_buff->current_byte << 24) |
+	(((uint) ((uchar) bit_buff->pos[2]))) |
+	  (((uint) ((uchar) bit_buff->pos[1])) << 8) |
+	    (((uint) ((uchar) bit_buff->pos[0])) << 16);
+      bit_buff->pos+=3;
+      bits+=24;
+#else
+      if (bits)				/* We must have at leasts 9 bits */
+      {
+	bit_buff->current_byte=  (bit_buff->current_byte << 8) |
+	  (uint) ((uchar) bit_buff->pos[0]);
+	bit_buff->pos++;
+	bits+=8;
+      }
+      else
+      {
+	bit_buff->current_byte= ((uint) ((uchar) bit_buff->pos[0]) << 8) |
+	  ((uint) ((uchar) bit_buff->pos[1]));
+	bit_buff->pos+=2;
+	bits+=16;
+      }
+#endif
+    }
+	/* First use info in quick_table */
+    low_byte=(bit_buff->current_byte >> (bits - table_bits)) & table_and;
+    low_byte=decode_tree->table[low_byte];
+    if (low_byte & IS_CHAR)
+    {
+      *to++ = (low_byte & 255);		/* Found char in quick table */
+      bits-=  ((low_byte >> 8) & 31);	/* Remove bits used */
+    }
+    else
+    {					/* Map through rest of decode-table */
+      pos=decode_tree->table+low_byte;
+      bits-=table_bits;
+      for (;;)
+      {
+	if (bits < 8)
+	{				/* We don't need to check end */
+#if BITS_SAVED == 32
+	  bit_buff->current_byte= (bit_buff->current_byte << 24) |
+	    (((uint) ((uchar) bit_buff->pos[2]))) |
+	      (((uint) ((uchar) bit_buff->pos[1])) << 8) |
+		(((uint) ((uchar) bit_buff->pos[0])) << 16);
+	  bit_buff->pos+=3;
+	  bits+=24;
+#else
+	  bit_buff->current_byte=  (bit_buff->current_byte << 8) |
+	    (uint) ((uchar) bit_buff->pos[0]);
+	  bit_buff->pos+=1;
+	  bits+=8;
+#endif
+	}
+	low_byte=(uint) (bit_buff->current_byte >> (bits-8));
+	decode_bytes_test_bit(0);
+	decode_bytes_test_bit(1);
+	decode_bytes_test_bit(2);
+	decode_bytes_test_bit(3);
+	decode_bytes_test_bit(4);
+	decode_bytes_test_bit(5);
+	decode_bytes_test_bit(6);
+	decode_bytes_test_bit(7);
+	bits-=8;
+      }
+      *to++ = (char) *pos;
+    }
+  } while (to != end);
+
+  bit_buff->bits=bits;
+  return;
+}
+#endif /* BIT_SAVED == 64 */
+
+
+static uint decode_pos(MARIA_BIT_BUFF *bit_buff,
+                       MARIA_DECODE_TREE *decode_tree)
+{
+  uint16 *pos=decode_tree->table;
+  for (;;)
+  {
+    if (get_bit(bit_buff))
+      pos++;
+    if (*pos & IS_CHAR)
+      return (uint) (*pos & ~IS_CHAR);
+    pos+= *pos;
+  }
+}
+
+
+int _ma_read_rnd_pack_record(MARIA_HA *info,
+                             uchar *buf,
+			     register MARIA_RECORD_POS filepos,
+			     my_bool skip_deleted_blocks)
+{
+  File file;
+  MARIA_BLOCK_INFO block_info;
+  MARIA_SHARE *share= info->s;
+  DBUG_ENTER("_ma_read_rnd_pack_record");
+
+  if (filepos >= info->state->data_file_length)
+  {
+    my_errno= HA_ERR_END_OF_FILE;
+    goto err;
+  }
+
+  file= info->dfile.file;
+  if (info->opt_flag & READ_CACHE_USED)
+  {
+    if (_ma_read_cache(info, &info->rec_cache, block_info.header,
+                       filepos, share->pack.ref_length,
+                       skip_deleted_blocks ? READING_NEXT : 0))
+      goto err;
+    file= -1;
+  }
+  if (_ma_pack_get_block_info(info, &info->bit_buff, &block_info,
+                              &info->rec_buff, &info->rec_buff_size,
+                              file, filepos))
+    goto err;					/* Error code is already set */
+#ifndef DBUG_OFF
+  if (block_info.rec_len > share->max_pack_length)
+  {
+    _ma_set_fatal_error(info, HA_ERR_WRONG_IN_RECORD);
+    goto err;
+  }
+#endif
+
+  if (info->opt_flag & READ_CACHE_USED)
+  {
+    if (_ma_read_cache(info, &info->rec_cache, info->rec_buff,
+                       block_info.filepos, block_info.rec_len,
+                       skip_deleted_blocks ? READING_NEXT : 0))
+      goto err;
+  }
+  else
+  {
+    if (mysql_file_read(info->dfile.file, info->rec_buff + block_info.offset,
+		block_info.rec_len-block_info.offset,
+		MYF(MY_NABP)))
+      goto err;
+  }
+  info->packed_length=   block_info.rec_len;
+  info->cur_row.lastpos= filepos;
+  info->cur_row.nextpos= block_info.filepos+block_info.rec_len;
+  info->update|= HA_STATE_AKTIV | HA_STATE_KEY_CHANGED;
+
+  info->rec_buff[block_info.rec_len]= 0; /* Keep valgrind happy */
+  DBUG_RETURN(_ma_pack_rec_unpack(info, &info->bit_buff, buf,
+                                  info->rec_buff, block_info.rec_len));
+ err:
+  DBUG_RETURN(my_errno);
+}
+
+
+	/* Read and process header from a huff-record-file */
+
+uint _ma_pack_get_block_info(MARIA_HA *maria, MARIA_BIT_BUFF *bit_buff,
+                             MARIA_BLOCK_INFO *info,
+                             uchar **rec_buff_p, size_t *rec_buff_size_p,
+                             File file, my_off_t filepos)
+{
+  uchar *header= info->header;
+  uint head_length,UNINIT_VAR(ref_length);
+  MARIA_SHARE *share= maria->s;
+  myf flag= MY_WME | (share->temporary ? MY_THREAD_SPECIFIC : 0);
+
+  if (file >= 0)
+  {
+    ref_length=share->pack.ref_length;
+    /*
+      We can't use my_pread() here because _ma_read_rnd_pack_record assumes
+      position is ok
+    */
+    mysql_file_seek(file,filepos,MY_SEEK_SET,MYF(0));
+    if (mysql_file_read(file, header,ref_length,MYF(MY_NABP)))
+      return BLOCK_FATAL_ERROR;
+    DBUG_DUMP("header", header, ref_length);
+  }
+  head_length= read_pack_length((uint) share->pack.version, header,
+                                &info->rec_len);
+  if (share->base.blobs)
+  {
+    head_length+= read_pack_length((uint) share->pack.version,
+                                   header + head_length, &info->blob_len);
+    /*
+      Ensure that the record buffer is big enough for the compressed
+      record plus all expanded blobs. [We do not have an extra buffer
+      for the resulting blobs. Sigh.]
+    */
+    if (_ma_alloc_buffer(rec_buff_p, rec_buff_size_p,
+                         info->rec_len + info->blob_len +
+                         share->base.extra_rec_buff_size, flag))
+      return BLOCK_FATAL_ERROR;			/* not enough memory */
+    bit_buff->blob_pos= *rec_buff_p + info->rec_len;
+    bit_buff->blob_end= bit_buff->blob_pos + info->blob_len;
+    maria->blob_length=info->blob_len;
+  }
+  info->filepos=filepos+head_length;
+  if (file >= 0)
+  {
+    info->offset=MY_MIN(info->rec_len, ref_length - head_length);
+    memcpy(*rec_buff_p, header + head_length, info->offset);
+  }
+  return 0;
+}
+
+
+	/* rutines for bit buffer */
+	/* Note buffer must be 6 uchar bigger than longest row */
+
+static void init_bit_buffer(MARIA_BIT_BUFF *bit_buff, uchar *buffer,
+                            uint length)
+{
+  bit_buff->pos=buffer;
+  bit_buff->end=buffer+length;
+  bit_buff->bits=bit_buff->error=0;
+  bit_buff->current_byte=0;			/* Avoid purify errors */
+}
+
+static uint fill_and_get_bits(MARIA_BIT_BUFF *bit_buff, uint count)
+{
+  uint tmp;
+  count-=bit_buff->bits;
+  tmp=(bit_buff->current_byte & mask[bit_buff->bits]) << count;
+  fill_buffer(bit_buff);
+  bit_buff->bits=BITS_SAVED - count;
+  return tmp+(bit_buff->current_byte >> (BITS_SAVED - count));
+}
+
+	/* Fill in empty bit_buff->current_byte from buffer */
+	/* Sets bit_buff->error if buffer is exhausted */
+
+static void fill_buffer(MARIA_BIT_BUFF *bit_buff)
+{
+  if (bit_buff->pos >= bit_buff->end)
+  {
+    bit_buff->error= 1;
+    bit_buff->current_byte=0;
+    return;
+  }
+#if BITS_SAVED == 64
+  bit_buff->current_byte=  ((((uint) ((uchar) bit_buff->pos[7]))) |
+			     (((uint) ((uchar) bit_buff->pos[6])) << 8) |
+			     (((uint) ((uchar) bit_buff->pos[5])) << 16) |
+			     (((uint) ((uchar) bit_buff->pos[4])) << 24) |
+			     ((ulonglong)
+			      ((((uint) ((uchar) bit_buff->pos[3]))) |
+			       (((uint) ((uchar) bit_buff->pos[2])) << 8) |
+			       (((uint) ((uchar) bit_buff->pos[1])) << 16) |
+			       (((uint) ((uchar) bit_buff->pos[0])) << 24)) << 32));
+  bit_buff->pos+=8;
+#else
+#if BITS_SAVED == 32
+  bit_buff->current_byte=  (((uint) ((uchar) bit_buff->pos[3])) |
+			     (((uint) ((uchar) bit_buff->pos[2])) << 8) |
+			     (((uint) ((uchar) bit_buff->pos[1])) << 16) |
+			     (((uint) ((uchar) bit_buff->pos[0])) << 24));
+  bit_buff->pos+=4;
+#else
+  bit_buff->current_byte=  (uint) (((uint) ((uchar) bit_buff->pos[1])) |
+				    (((uint) ((uchar) bit_buff->pos[0])) << 8));
+  bit_buff->pos+=2;
+#endif
+#endif
+}
+
+	/* Get number of bits neaded to represent value */
+
+static uint max_bit(register uint value)
+{
+  reg2 uint power=1;
+
+  while ((value>>=1))
+    power++;
+  return (power);
+}
+
+
+/*****************************************************************************
+	Some redefined functions to handle files when we are using memmap
+*****************************************************************************/
+
+#ifdef HAVE_MMAP
+
+static int _ma_read_mempack_record(MARIA_HA *info, uchar *buf,
+                                   MARIA_RECORD_POS filepos);
+static int _ma_read_rnd_mempack_record(MARIA_HA*, uchar *, MARIA_RECORD_POS,
+                                       my_bool);
+
+my_bool _ma_memmap_file(MARIA_HA *info)
+{
+  MARIA_SHARE *share= info->s;
+  DBUG_ENTER("maria_memmap_file");
+
+  if (!info->s->file_map)
+  {
+    if (mysql_file_seek(info->dfile.file, 0L, MY_SEEK_END, MYF(0)) <
+        share->state.state.data_file_length+MEMMAP_EXTRA_MARGIN)
+    {
+      DBUG_PRINT("warning",("File isn't extended for memmap"));
+      DBUG_RETURN(0);
+    }
+    if (_ma_dynmap_file(info, share->state.state.data_file_length))
+      DBUG_RETURN(0);
+  }
+  info->opt_flag|= MEMMAP_USED;
+  info->read_record= share->read_record= _ma_read_mempack_record;
+  share->scan= _ma_read_rnd_mempack_record;
+  DBUG_RETURN(1);
+}
+
+
+void _ma_unmap_file(MARIA_HA *info)
+{
+  MARIA_SHARE *share= info->s;
+  my_munmap((char*) share->file_map,
+            (size_t) share->mmaped_length + MEMMAP_EXTRA_MARGIN);
+  share->file_map= 0;
+  share->file_read= _ma_nommap_pread;
+  share->file_write= _ma_nommap_pwrite;
+  info->opt_flag&= ~MEMMAP_USED;
+}
+
+
+static uchar *
+_ma_mempack_get_block_info(MARIA_HA *maria,
+                           MARIA_BIT_BUFF *bit_buff,
+                           MARIA_BLOCK_INFO *info,
+                           uchar **rec_buff_p,
+                           size_t *rec_buff_size_p,
+                           uchar *header)
+{
+  MARIA_SHARE *share= maria->s;
+  myf flag= MY_WME | (share->temporary ? MY_THREAD_SPECIFIC : 0);
+
+  header+= read_pack_length((uint) share->pack.version, header,
+                            &info->rec_len);
+  if (share->base.blobs)
+  {
+    header+= read_pack_length((uint) share->pack.version, header,
+                              &info->blob_len);
+    /* _ma_alloc_rec_buff sets my_errno on error */
+    if (_ma_alloc_buffer(rec_buff_p, rec_buff_size_p,
+                      info->blob_len + share->base.extra_rec_buff_size, flag))
+      return 0;				/* not enough memory */
+    bit_buff->blob_pos= *rec_buff_p;
+    bit_buff->blob_end= *rec_buff_p + info->blob_len;
+  }
+  return header;
+}
+
+
+static int _ma_read_mempack_record(MARIA_HA *info, uchar *buf,
+                                   MARIA_RECORD_POS filepos)
+{
+  MARIA_BLOCK_INFO block_info;
+  MARIA_SHARE *share= info->s;
+  uchar *pos;
+  DBUG_ENTER("maria_read_mempack_record");
+
+  if (filepos == HA_OFFSET_ERROR)
+    DBUG_RETURN(my_errno);          /* _search() didn't find record */
+
+  if (!(pos= (uchar*) _ma_mempack_get_block_info(info, &info->bit_buff,
+                                                &block_info, &info->rec_buff,
+                                                &info->rec_buff_size,
+						(uchar*) share->file_map+
+						filepos)))
+    DBUG_RETURN(my_errno);
+  DBUG_RETURN(_ma_pack_rec_unpack(info, &info->bit_buff, buf,
+                                  pos, block_info.rec_len));
+}
+
+
+/*ARGSUSED*/
+static int _ma_read_rnd_mempack_record(MARIA_HA *info,
+                                       uchar *buf,
+				       register MARIA_RECORD_POS filepos,
+				       my_bool skip_deleted_blocks
+				       __attribute__((unused)))
+{
+  MARIA_BLOCK_INFO block_info;
+  MARIA_SHARE *share= info->s;
+  uchar *pos,*start;
+  DBUG_ENTER("_ma_read_rnd_mempack_record");
+
+  if (filepos >= share->state.state.data_file_length)
+  {
+    my_errno=HA_ERR_END_OF_FILE;
+    goto err;
+  }
+  if (!(pos= (uchar*) _ma_mempack_get_block_info(info, &info->bit_buff,
+                                                &block_info,
+                                                &info->rec_buff,
+                                                &info->rec_buff_size,
+						(uchar*)
+                                                (start= share->file_map +
+						 filepos))))
+    goto err;
+#ifndef DBUG_OFF
+  if (block_info.rec_len > info->s->max_pack_length)
+  {
+    _ma_set_fatal_error(info, HA_ERR_WRONG_IN_RECORD);
+    goto err;
+  }
+#endif
+  info->packed_length=block_info.rec_len;
+  info->cur_row.lastpos= filepos;
+  info->cur_row.nextpos= filepos+(uint) (pos-start)+block_info.rec_len;
+  info->update|= HA_STATE_AKTIV | HA_STATE_KEY_CHANGED;
+
+  DBUG_RETURN (_ma_pack_rec_unpack(info, &info->bit_buff, buf,
+                                   pos, block_info.rec_len));
+ err:
+  DBUG_RETURN(my_errno);
+}
+
+#endif /* HAVE_MMAP */
+
+	/* Save length of row */
+
+uint _ma_save_pack_length(uint version, uchar *block_buff, ulong length)
+{
+  if (length < 254)
+  {
+    *(uchar*) block_buff= (uchar) length;
+    return 1;
+  }
+  if (length <= 65535)
+  {
+    *(uchar*) block_buff=254;
+    int2store(block_buff+1,(uint) length);
+    return 3;
+  }
+  *(uchar*) block_buff=255;
+  if (version == 1) /* old format */
+  {
+    DBUG_ASSERT(length <= 0xFFFFFF);
+    int3store(block_buff + 1, (ulong) length);
+    return 4;
+  }
+  else
+  {
+    int4store(block_buff + 1, (ulong) length);
+    return 5;
+  }
+}
+
+
+static uint read_pack_length(uint version, const uchar *buf, ulong *length)
+{
+  if (buf[0] < 254)
+  {
+    *length= buf[0];
+    return 1;
+  }
+  else if (buf[0] == 254)
+  {
+    *length= uint2korr(buf + 1);
+    return 3;
+  }
+  if (version == 1) /* old format */
+  {
+    *length= uint3korr(buf + 1);
+    return 4;
+  }
+  else
+  {
+    *length= uint4korr(buf + 1);
+    return 5;
+  }
+}
+
+
+uint _ma_calc_pack_length(uint version, ulong length)
+{
+  return (length < 254) ? 1 : (length < 65536) ? 3 : (version == 1) ? 4 : 5;
+}