Merge with 4.0.17

1 files changed, 44 insertions, 10 deletions

diff --git a/myisam/mi_key.c b/myisam/mi_key.c
index 93e3b9621f3..97af156e89a 100644
--- a/myisam/mi_key.c
+++ b/myisam/mi_key.c
@@ -19,6 +19,7 @@
 #include "myisamdef.h"
 #include "m_ctype.h"
 #include "sp_defs.h"
+#include <assert.h>
 #ifdef HAVE_IEEEFP_H
 #include <ieeefp.h>
 #endif
@@ -397,53 +398,86 @@ int _mi_read_key_record(MI_INFO *info, my_off_t filepos, byte *buf)
   return(-1);				/* Wrong data to read */
 }
 
+  
+/*
+  Update auto_increment info
 
-	/* Update auto_increment info */
+  SYNOPSIS
+    update_auto_increment()
+    info			MyISAM handler
+    record			Row to update
+
+  IMPLEMENTATION
+    Only replace the auto_increment value if it is higher than the previous
+    one. For signed columns we don't update the auto increment value if it's
+    less than zero.
+*/
 
 void update_auto_increment(MI_INFO *info,const byte *record)
 {
-  ulonglong value;
-  HA_KEYSEG *keyseg=info->s->keyinfo[info->s->base.auto_key-1].seg;
-  const uchar *key=(uchar*) record+keyseg->start;
+  ulonglong value= 0;			/* Store unsigned values here */
+  longlong s_value= 0;			/* Store signed values here */
+  HA_KEYSEG *keyseg= info->s->keyinfo[info->s->base.auto_key-1].seg;
+  const uchar *key= (uchar*) record + keyseg->start;
 
   switch (keyseg->type) {
   case HA_KEYTYPE_INT8:
+    s_value= (longlong) *(char*)key;
+    break;
   case HA_KEYTYPE_BINARY:
     value=(ulonglong)  *(uchar*) key;
     break;
   case HA_KEYTYPE_SHORT_INT:
+    s_value= (longlong) sint2korr(key);
+    break;
   case HA_KEYTYPE_USHORT_INT:
     value=(ulonglong) uint2korr(key);
     break;
   case HA_KEYTYPE_LONG_INT:
+    s_value= (longlong) sint4korr(key);
+    break;
   case HA_KEYTYPE_ULONG_INT:
     value=(ulonglong) uint4korr(key);
     break;
   case HA_KEYTYPE_INT24:
+    s_value= (longlong) sint3korr(key);
+    break;
   case HA_KEYTYPE_UINT24:
     value=(ulonglong) uint3korr(key);
     break;
-  case HA_KEYTYPE_FLOAT:			/* This shouldn't be used */
+  case HA_KEYTYPE_FLOAT:                        /* This shouldn't be used */
   {
     float f_1;
     float4get(f_1,key);
-    value = (ulonglong) f_1;
+    /* Ignore negative values */
+    value = (f_1 < (float) 0.0) ? 0 : (ulonglong) f_1;
     break;
   }
-  case HA_KEYTYPE_DOUBLE:			/* This shouldn't be used */
+  case HA_KEYTYPE_DOUBLE:                       /* This shouldn't be used */
   {
     double f_1;
     float8get(f_1,key);
-    value = (ulonglong) f_1;
+    /* Ignore negative values */
+    value = (f_1 < 0.0) ? 0 : (ulonglong) f_1;
     break;
   }
   case HA_KEYTYPE_LONGLONG:
+    s_value= sint8korr(key);
+    break;
   case HA_KEYTYPE_ULONGLONG:
     value= uint8korr(key);
     break;
   default:
-    value=0;					/* Error */
+    DBUG_ASSERT(0);
+    value=0;                                    /* Error */
     break;
   }
-  set_if_bigger(info->s->state.auto_increment,value);
+
+  /*
+    The following code works becasue if s_value < 0 then value is 0
+    and if s_value == 0 then value will contain either s_value or the
+    correct value.
+  */
+  set_if_bigger(info->s->state.auto_increment,
+                (s_value > 0) ? (ulonglong) s_value : value);
 }