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Add MutableObjectId setByte to modify a mutable id 

This mirrors the getByte() API in ObjectId and allows the caller to
modify a single byte, which is useful when updating it as part of a
loop walking through 0x00..0xff inside of a range of objects.

Change-Id: I57fa8420011fe5ed5fc6bfeb26f87a02b3197dab
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
This commit is contained in:
Shawn O. Pearce 2010-11-03 19:01:53 -07:00
parent b22a4e8488
commit e488f1cacd
2 changed files with 83 additions and 0 deletions
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29
org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectIdTest.java
View File

@ -122,4 +122,33 @@ public void testGetByte() {
for (int i = 2; i < 20; i++)
assertEquals("index " + i, raw[i] & 0xff, id.getByte(i));
}
public void testSetByte() {
byte[] exp = new byte[20];
for (int i = 0; i < 20; i++)
exp[i] = (byte) (0xa0 + i);
MutableObjectId id = new MutableObjectId();
id.fromRaw(exp);
assertEquals(ObjectId.fromRaw(exp).name(), id.name());
id.setByte(0, 0x10);
assertEquals(0x10, id.getByte(0));
exp[0] = 0x10;
assertEquals(ObjectId.fromRaw(exp).name(), id.name());
for (int p = 1; p < 20; p++) {
id.setByte(p, 0x10 + p);
assertEquals(0x10 + p, id.getByte(p));
exp[p] = (byte) (0x10 + p);
assertEquals(ObjectId.fromRaw(exp).name(), id.name());
}
for (int p = 0; p < 20; p++) {
id.setByte(p, 0x80 + p);
assertEquals(0x80 + p, id.getByte(p));
exp[p] = (byte) (0x80 + p);
assertEquals(ObjectId.fromRaw(exp).name(), id.name());
}
}
}

54
org.eclipse.jgit/src/org/eclipse/jgit/lib/MutableObjectId.java
View File

@ -74,6 +74,60 @@ public MutableObjectId() {
fromObjectId(src);
}
/**
* Set any byte in the id.
*
* @param index
* index of the byte to set in the raw form of the ObjectId. Must
* be in range [0, {@link Constants#OBJECT_ID_LENGTH}).
* @param value
* the value of the specified byte at {@code index}. Values are
* unsigned and thus are in the range [0,255] rather than the
* signed byte range of [-128, 127].
* @throws ArrayIndexOutOfBoundsException
* {@code index} is less than 0, equal to
* {@link Constants#OBJECT_ID_LENGTH}, or greater than
* {@link Constants#OBJECT_ID_LENGTH}.
*/
public void setByte(int index, int value) {
switch (index >> 2) {
case 0:
w1 = set(w1, index & 3, value);
break;
case 1:
w2 = set(w2, index & 3, value);
break;
case 2:
w3 = set(w3, index & 3, value);
break;
case 3:
w4 = set(w4, index & 3, value);
break;
case 4:
w5 = set(w5, index & 3, value);
break;
default:
throw new ArrayIndexOutOfBoundsException(index);
}
}
private static int set(int w, int index, int value) {
value &= 0xff;
switch (index) {
case 0:
return (w & 0x00ffffff) | (value << 24);
case 1:
return (w & 0xff00ffff) | (value << 16);
case 2:
return (w & 0xffff00ff) | (value << 8);
case 3:
return (w & 0xffffff00) | value;
default:
throw new ArrayIndexOutOfBoundsException();
}
}
/** Make this id match {@link ObjectId#zeroId()}. */
public void clear() {
w1 = 0;