1 files changed, 18 insertions, 16 deletions

diff --git a/src/func.c b/src/func.c
index bd25a44d4..5784b75e2 100644
--- a/src/func.c
+++ b/src/func.c
@@ -356,11 +356,6 @@ static void substrFunc(
   i64 p1, p2;
 
   assert( argc==3 || argc==2 );
-  if( sqlite3_value_type(argv[1])==SQLITE_NULL
-   || (argc==3 && sqlite3_value_type(argv[2])==SQLITE_NULL)
-  ){
-    return;
-  }
   p0type = sqlite3_value_type(argv[0]);
   p1 = sqlite3_value_int64(argv[1]);
   if( p0type==SQLITE_BLOB ){
@@ -378,19 +373,23 @@ static void substrFunc(
       }
     }
   }
-#ifdef SQLITE_SUBSTR_COMPATIBILITY
-  /* If SUBSTR_COMPATIBILITY is defined then substr(X,0,N) work the same as
-  ** as substr(X,1,N) - it returns the first N characters of X.  This
-  ** is essentially a back-out of the bug-fix in check-in [5fc125d362df4b8]
-  ** from 2009-02-02 for compatibility of applications that exploited the
-  ** old buggy behavior. */
-  if( p1==0 ) p1 = 1; /* <rdar://problem/6778339> */
-#endif
   if( argc==3 ){
     p2 = sqlite3_value_int64(argv[2]);
+    if( p2==0 && sqlite3_value_type(argv[2])==SQLITE_NULL ) return;
   }else{
     p2 = sqlite3_context_db_handle(context)->aLimit[SQLITE_LIMIT_LENGTH];
   }
+  if( p1==0 ){
+#ifdef SQLITE_SUBSTR_COMPATIBILITY
+    /* If SUBSTR_COMPATIBILITY is defined then substr(X,0,N) work the same as
+    ** as substr(X,1,N) - it returns the first N characters of X.  This
+    ** is essentially a back-out of the bug-fix in check-in [5fc125d362df4b8]
+    ** from 2009-02-02 for compatibility of applications that exploited the
+    ** old buggy behavior. */
+    p1 = 1; /* <rdar://problem/6778339> */
+#endif
+    if( sqlite3_value_type(argv[1])==SQLITE_NULL ) return;
+  }
   if( p1<0 ){
     p1 += len;
     if( p1<0 ){
@@ -1421,7 +1420,7 @@ static void replaceFunc(
   assert( zRep==sqlite3_value_text(argv[2]) );
   nOut = nStr + 1;
   assert( nOut<SQLITE_MAX_LENGTH );
-  zOut = contextMalloc(context, (i64)nOut);
+  zOut = contextMalloc(context, nOut);
   if( zOut==0 ){
     return;
   }
@@ -1571,7 +1570,7 @@ static void concatFuncCore(
   for(i=0; i<argc; i++){
     n += sqlite3_value_bytes(argv[i]);
   }
-  n += (argc-1)*nSep;
+  n += (argc-1)*(i64)nSep;
   z = sqlite3_malloc64(n+1);
   if( z==0 ){
     sqlite3_result_error_nomem(context);
@@ -1869,7 +1868,10 @@ static void sumInverse(sqlite3_context *context, int argc, sqlite3_value**argv){
     assert( p->cnt>0 );
     p->cnt--;
     if( !p->approx ){
-      p->iSum -= sqlite3_value_int64(argv[0]);
+      if( sqlite3SubInt64(&p->iSum, sqlite3_value_int64(argv[0])) ){
+        p->ovrfl = 1;
+        p->approx = 1;
+      }
     }else if( type==SQLITE_INTEGER ){
       i64 iVal = sqlite3_value_int64(argv[0]);
       if( iVal!=SMALLEST_INT64 ){