1. Implemented binary search in array

Oleg Bartunov

diff --git a/contrib/intarray/README.intarray b/contrib/intarray/README.intarray
index 9f0374aca5faaecf813fad45c0962b9245762683..f0138a148427f46de71d3ece8d63ad0f7086b45e 100644 (file)
--- a/contrib/intarray/README.intarray
+++ b/contrib/intarray/README.intarray
@@ -12,6 +12,8 @@ for additional information.
 
 CHANGES:
 
+October 1, 2001
+   1. Change search method in array to binary
 September 28, 2001
    1. gist__int_ops now is without lossy
    2. add sort entry in picksplit

diff --git a/contrib/intarray/_int.c b/contrib/intarray/_int.c
index 3f38cdb0b03436b417b5c0e4bf17a1048dfa765c..a642998cd444003040af75884865a8bc06e5f0dc 100644 (file)
--- a/contrib/intarray/_int.c
+++ b/contrib/intarray/_int.c
@@ -1741,33 +1741,29 @@ makepol(WORKSTATE *state) {
 typedef struct {
        int4 *arrb;
        int4 *arre;
-       int4 *ptr;
 } CHKVAL;
 
 /*
  * is there value 'val' in array or not ?
- */ 
+ */
 static bool
 checkcondition_arr( void *checkval, int4 val ) {
-#ifdef BS_DEBUG
-       elog(NOTICE,"OPERAND %d", val);
-#endif
-       if ( val > *(((CHKVAL*)checkval)->ptr) ) {
-               while ( ((CHKVAL*)checkval)->ptr < ((CHKVAL*)checkval)->arre ) {
-                       ((CHKVAL*)checkval)->ptr++;
-                       if ( *(((CHKVAL*)checkval)->ptr) == val ) return true;
-                       if ( val < *(((CHKVAL*)checkval)->ptr) ) return false;
-               }
-       } else if ( val < *(((CHKVAL*)checkval)->ptr) ) { 
-               while ( ((CHKVAL*)checkval)->ptr > ((CHKVAL*)checkval)->arrb ) {
-                       ((CHKVAL*)checkval)->ptr--;
-                       if ( *(((CHKVAL*)checkval)->ptr) == val ) return true;
-                       if ( val > *(((CHKVAL*)checkval)->ptr) ) return false;
-               }
-       } else {
-               return true;
+       int4      *StopLow = ((CHKVAL*)checkval)->arrb;
+       int4      *StopHigh = ((CHKVAL*)checkval)->arre;
+       int4      *StopMiddle;
+
+       /* Loop invariant: StopLow <= val < StopHigh */
+
+       while (StopLow < StopHigh) {
+               StopMiddle = StopLow + (StopHigh - StopLow) / 2;
+               if (*StopMiddle == val)
+                       return (true);
+               else if (*StopMiddle < val )
+                       StopLow = StopMiddle + 1;
+               else
+                       StopHigh = StopMiddle;
        }
-       return false;   
+       return false;
 }
 
 static bool
@@ -1818,8 +1814,7 @@ execconsistent( QUERYTYPE *query, ArrayType *array, bool calcnot ) {
        CHKVAL  chkval;
 
        chkval.arrb = ARRPTR(array);
-       chkval.arre = chkval.arrb + ARRNELEMS(array) - 1;
-       chkval.ptr  = chkval.arrb + ARRNELEMS(array)/2;
+       chkval.arre = chkval.arrb + ARRNELEMS(array);
        return execute( 
                GETQUERY(query) + query->size-1 , 
                (void*)&chkval, calcnot, 
@@ -1854,8 +1849,7 @@ boolop(PG_FUNCTION_ARGS) {
 
        PREPAREARR(val);
        chkval.arrb = ARRPTR(val);
-       chkval.arre = chkval.arrb + ARRNELEMS(val) - 1;
-       chkval.ptr  = chkval.arrb + ARRNELEMS(val)/2;
+       chkval.arre = chkval.arrb + ARRNELEMS(val);
        result = execute( 
                GETQUERY(query) + query->size-1 , 
                &chkval, true,