medfall

commit 32583202329b1d8972035584e5973b794faa56f6
parent 3b786fb1d3d07fc3b58f67b0662b842a10a1bebd
Author: Michael Savage <mikejsavage@gmail.com>
Date:   Tue Sep  6 18:08:29 -0700

Add slots_required intrinsic

Diffstat:
hashtable.h
 | 
7
+++----
intrinsics.h
 | 
4
++++
2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/hashtable.h b/hashtable.h
@@ -99,11 +99,10 @@ private:
 	 * states is a bitfield with 2 bits per slot. the 2 bits are used to
 	 * hold one of 3 possible states: EMPTY, OCCUPIED and DELETED
 	 *
-	 * we want to round 2 * N up to the next multiple of 8, then divide by
-	 * 8 to get the number of bytes required. the form below is simplified
-	 * so it doesn't overflow
+	 * we want to round 2 * N up to the next multiple of 8, which is the
+	 * same as rounding N up to the next multiple of 4 but avoids overflow
 	 */
-	u8 states[ N / 4 + int( N % 4 != 0 ) ];
+	u8 states[ slots_required( N, 4 ) ];
 	u64 keys[ N ];
 	u64 values[ N ];
 };
diff --git a/intrinsics.h b/intrinsics.h
@@ -83,6 +83,10 @@ T clamp11( T x ) {
 	return clamp( x, T( -1 ), T( 1 ) );
 }
 
+inline constexpr size_t slots_required( size_t data_size, size_t slot_size ) {
+	return data_size / slot_size + ( data_size % slot_size != 0 );
+}
+
 #include "platform_backtrace.h"
 
 #if defined( assert )