yet another generalization for rec_buff handling, MI_INFO doesn't need rec_alloc anymore

myisam/mi_close.c:
  yet another generalization for rec_buff handling
myisam/mi_dynrec.c:
  yet another generalization for rec_buff handling
myisam/mi_extra.c:
  yet another generalization for rec_buff handling
myisam/mi_open.c:
  yet another generalization for rec_buff handling
myisam/myisamdef.h:
  yet another generalization for rec_buff handling

myisam/mi_close.c

@@ -101,7 +101,7 @@ int mi_close(register MI_INFO *info)
     error = my_errno;
 
   myisam_log_command(MI_LOG_CLOSE,info,NULL,0,error);
-  my_free((gptr) info->rec_alloc,MYF(MY_ALLOW_ZERO_PTR));
+  my_free(mi_get_rec_buff_ptr(info, info->rec_buff), MYF(MY_ALLOW_ZERO_PTR));
   my_free((gptr) info,MYF(0));
 
   if (error)

myisam/mi_dynrec.c

@@ -724,8 +724,8 @@ uint _mi_rec_pack(MI_INFO *info, register byte *to, register const byte *from)
 
 
 /*
-** Check if a record was correctly packed. Used only by isamchk
-** Returns 0 if record is ok.
+  Check if a record was correctly packed. Used only by myisamchk
+  Returns 0 if record is ok.
 */
 
 my_bool _mi_rec_check(MI_INFO *info,const char *record)
@@ -1090,39 +1090,12 @@ err:
   DBUG_RETURN(-1);
 }
 
-
-byte *mi_fix_rec_buff_for_blob(MI_INFO *info, ulong length)
-{
-  uint extra;
-
-  /* to simplify initial init of info->rec_buf in mi_open and mi_extra */
-  if (!length)
-      length=max(info->s->base.pack_reclength,info->s->base.max_key_length);
-
-  if (! info->rec_buff || length > info->alloced_rec_buff_length)
-  {
-    byte *newptr;
-    extra= ((info->s->options & HA_OPTION_PACK_RECORD) ?
-        ALIGN_SIZE(MI_MAX_DYN_BLOCK_HEADER)+MI_SPLIT_LENGTH+
-        MI_DYN_DELETE_BLOCK_HEADER : 0);
-    if (!(newptr=(byte*) my_realloc((gptr) info->rec_alloc,length+extra+8,
-				    MYF(MY_ALLOW_ZERO_PTR))))
-      return (byte *)0;
-    info->rec_alloc=newptr;
-    info->rec_buff=newptr+(extra ?
-                   ALIGN_SIZE(MI_DYN_DELETE_BLOCK_HEADER) : 0);
-    info->alloced_rec_buff_length=length;
-  }
-  return info->rec_buff;
-}
-
-
 	/* compare unique constraint between stored rows */
 
 int _mi_cmp_dynamic_unique(MI_INFO *info, MI_UNIQUEDEF *def,
 			   const byte *record, my_off_t pos)
 {
-  byte *rec_buff,*rec_alloc,*old_record;
+  byte *rec_buff,*old_record;
   uint alloced_rec_buff_length;
   int error;
   DBUG_ENTER("_mi_cmp_dynamic_unique");
@@ -1132,12 +1105,10 @@ int _mi_cmp_dynamic_unique(MI_INFO *info, MI_UNIQUEDEF *def,
 
   /* Don't let the compare destroy blobs that may be in use */
   rec_buff=info->rec_buff;
-  rec_alloc=info->rec_alloc;
   alloced_rec_buff_length=info->alloced_rec_buff_length;
   if (info->s->base.blobs)
   {
     info->rec_buff=0;
-    info->rec_alloc=0;
     info->alloced_rec_buff_length=0;
   }
   error=_mi_read_dynamic_record(info,pos,old_record);
@@ -1145,9 +1116,8 @@ int _mi_cmp_dynamic_unique(MI_INFO *info, MI_UNIQUEDEF *def,
     error=mi_unique_comp(def, record, old_record, def->null_are_equal);
   if (info->s->base.blobs)
   {
-    my_free(info->rec_alloc,MYF(MY_ALLOW_ZERO_PTR));
+    my_free(mi_get_rec_buff_ptr(info, info->rec_buff), MYF(MY_ALLOW_ZERO_PTR));
     info->rec_buff=rec_buff;
-    info->rec_alloc=rec_alloc;
     info->alloced_rec_buff_length=alloced_rec_buff_length;
   }
   my_afree(old_record);

myisam/mi_extra.c

@@ -328,11 +328,7 @@ int mi_extra(MI_INFO *info, enum ha_extra_function function)
       }
     }
     if (share->base.blobs)
-    {
-      my_free(info->rec_alloc,MYF(MY_ALLOW_ZERO_PTR));
-      info->rec_alloc=info->rec_buff=0;
-      mi_fix_rec_buff_for_blob(info, 0);
-    }
+      mi_fix_rec_buff_for_blob(info, -1);
     break;
   case HA_EXTRA_NORMAL:				/* Theese isn't in use */
     info->quick_mode=0;

myisam/mi_open.c

@@ -507,9 +507,9 @@ MI_INFO *mi_open(const char *name, int mode, uint open_flags)
   /* Allocate buffer for one record */
 
   /* prerequisites: bzero(info) && info->s=share; are met. */
-  if (!mi_fix_rec_buff_for_blob(&info, 0))
+  if (!mi_fix_rec_buff_for_blob(&info, -1))
     goto err;
-  bzero(info.rec_alloc, info.alloced_rec_buff_length);
+  bzero(info.rec_buff, info.alloced_rec_buff_length);
 
   *m_info=info;
 #ifdef THREAD
@@ -559,6 +559,39 @@ err:
   DBUG_RETURN (NULL);
 } /* mi_open */
 
+gptr mi_get_rec_buff_ptr(MI_INFO *info, byte *buf)
+{
+  if (info->s->options & HA_OPTION_PACK_RECORD && buf)
+    return buf - MI_REC_BUFF_OFFSET;
+  else
+    return buf;
+}
+
+byte *mi_alloc_rec_buff(MI_INFO *info, ulong length, byte **buf, uint *buf_len)
+{
+  uint extra;
+
+  if (! *buf || length > *buf_len)
+  {
+    byte *newptr = *buf;
+
+    /* to simplify initial init of info->rec_buf in mi_open and mi_extra */
+    if (length == (ulong)-1)
+        length=max(info->s->base.pack_reclength,info->s->base.max_key_length);
+
+    extra= ((info->s->options & HA_OPTION_PACK_RECORD) ?
+             ALIGN_SIZE(MI_MAX_DYN_BLOCK_HEADER)+MI_SPLIT_LENGTH+
+             MI_REC_BUFF_OFFSET : 0);
+    if (extra && newptr)
+      newptr-=MI_REC_BUFF_OFFSET;
+    if (!(newptr=(byte*) my_realloc((gptr)newptr, length+extra+8,
+				    MYF(MY_ALLOW_ZERO_PTR))))
+      return 0;
+    *buf=newptr+(extra ?  MI_REC_BUFF_OFFSET : 0);
+    *buf_len=length;
+  }
+  return *buf;
+}
 
 ulonglong mi_safe_mul(ulonglong a, ulonglong b)
 {

myisam/myisamdef.h

@@ -222,12 +222,11 @@ struct st_myisam_info {
   MI_BLOB     *blobs;			/* Pointer to blobs */
   MI_BIT_BUFF  bit_buff;
   /* accumulate indexfile changes between write's */
-  TREE	      *bulk_insert;   
+  TREE	      *bulk_insert;
   char *filename;			/* parameter to open filename */
   uchar *buff,				/* Temp area for key */
 	*lastkey,*lastkey2;		/* Last used search key */
-  byte	*rec_buff,			/* Tempbuff for recordpack */
-	*rec_alloc;			/* Malloced area for record */
+  byte	*rec_buff;			/* Tempbuff for recordpack */
   uchar *int_keypos,			/* Save position for next/previous */
         *int_maxpos;			/*  -""-  */
   int (*read_record)(struct st_myisam_info*, my_off_t, byte*);
@@ -249,7 +248,7 @@ struct st_myisam_info {
   uint opt_flag;			/* Optim. for space/speed */
   uint update;				/* If file changed since open */
   uint	alloced_rec_buff_length;	/* Max recordlength malloced */
-  uint   int_nod_flag;			/*  -""-  */
+  uint  int_nod_flag;			/*  -""-  */
   int	lastinx;			/* Last used index */
   uint	lastkey_length;			/* Length of key in lastkey */
   uint	last_rkey_length;		/* Last length in mi_rkey() */
@@ -360,6 +359,7 @@ struct st_myisam_info {
 #define MI_DYN_ALIGN_SIZE	4	/* Align blocks on this */
 #define MI_MAX_DYN_HEADER_BYTE	13	/* max header byte for dynamic rows */
 #define MI_MAX_BLOCK_LENGTH	((((ulong) 1 << 24)-1) & (~ (ulong) (MI_DYN_ALIGN_SIZE-1)))
+#define MI_REC_BUFF_OFFSET      ALIGN_SIZE(MI_DYN_DELETE_BLOCK_HEADER)
 
 #define MEMMAP_EXTRA_MARGIN	7	/* Write this as a suffix for file */
 
@@ -523,7 +523,11 @@ extern int _mi_read_key_record(MI_INFO *info,my_off_t filepos,byte *buf);
 extern int _mi_read_cache(IO_CACHE *info,byte *buff,my_off_t pos,
 			  uint length,int re_read_if_possibly);
 extern void update_auto_increment(MI_INFO *info,const byte *record);
-extern byte *mi_fix_rec_buff_for_blob(MI_INFO *info,ulong blob_length);
+extern byte *mi_alloc_rec_buff(MI_INFO *,ulong, byte**, uint*);
+extern gptr mi_get_rec_buff_ptr(MI_INFO *, byte *);
+#define mi_fix_rec_buff_for_blob(INFO,LENGTH)  \
+            mi_alloc_rec_buff((INFO),(LENGTH), \
+              &((INFO)->rec_buff), &((INFO)->alloced_rec_buff_length))
 extern ulong _mi_rec_unpack(MI_INFO *info,byte *to,byte *from,
 			    ulong reclength);
 extern my_bool _mi_rec_check(MI_INFO *info,const char *from);