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,