Thread (26 messages) flat view 26 messages, 2 authors, 2016-06-15
STALE3735d

[JGIT PATCH 20/23] Move "wantWrite" field of ObjectToPack into the flags field

From: Shawn O. Pearce <hidden>
Date: 2016-06-15 22:45:49
Subsystem: the rest · Maintainer: Linus Torvalds

This reduces the ObjectToPack structure by 4 bytes, saving us 4 MB
on the linux kernel repository.  Its only a single bit value, so
keeping it in a full boolean is rather wasteful given how many of
these objects we need in to pack a large project.

Signed-off-by: Shawn O. Pearce <redacted>
---
 .../src/org/spearce/jgit/lib/PackWriter.java       |   23 ++++++++++++-------
 1 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/PackWriter.java b/org.spearce.jgit/src/org/spearce/jgit/lib/PackWriter.java
index 50d06c2..3ef9154 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/lib/PackWriter.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/PackWriter.java
@@ -859,11 +859,16 @@ public void addObject(final RevObject object)
 
 		private PackedObjectLoader reuseLoader;
 
-		/** Low bits contain the objectType; higher bits the deltaDepth */
+		/**
+		 * Bit field, from bit 0 to bit 31:
+		 * <ul>
+		 * <li>1 bit: wantWrite</li>
+		 * <li>3 bits: type</li>
+		 * <li>28 bits: deltaDepth</li>
+		 * </ul>
+		 */
 		private int flags;
 
-		private boolean wantWrite;
-
 		/**
 		 * Construct object for specified object id. <br/> By default object is
 		 * marked as not written and non-delta packed (as a whole object).
@@ -875,7 +880,7 @@ public void addObject(final RevObject object)
 		 */
 		ObjectToPack(AnyObjectId src, final int type) {
 			super(src);
-			flags |= type;
+			flags |= type << 1;
 		}
 
 		/**
@@ -952,11 +957,11 @@ void disposeLoader() {
 		}
 
 		int getType() {
-			return flags & 0x7;
+			return (flags>>1) & 0x7;
 		}
 
 		int getDeltaDepth() {
-			return flags >>> 3;
+			return flags >>> 4;
 		}
 
 		void updateDeltaDepth() {
@@ -967,15 +972,15 @@ else if (deltaBase != null)
 				d = 1;
 			else
 				d = 0;
-			flags = (d << 3) | getType();
+			flags = (d << 4) | flags & 0x15;
 		}
 
 		boolean wantWrite() {
-			return wantWrite;
+			return (flags & 1) == 1;
 		}
 
 		void markWantWrite() {
-			this.wantWrite = true;
+			flags |= 1;
 		}
 	}
 }
-- 
1.6.1.rc4.301.g5497a
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