NB: encode and decode 24-bit ints
Change-Id: Ie036dc46e5a88a4e87dc52e880505bbe34601ca7
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/NBTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/NBTest.java
index 7e11a61..d2d44ff 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/NBTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/NBTest.java
@@ -90,6 +90,24 @@
}
@Test
+ public void testDecodeUInt24() {
+ assertEquals(0, NB.decodeUInt24(b(0, 0, 0), 0));
+ assertEquals(0, NB.decodeUInt24(padb(3, 0, 0, 0), 3));
+
+ assertEquals(3, NB.decodeUInt24(b(0, 0, 3), 0));
+ assertEquals(3, NB.decodeUInt24(padb(3, 0, 0, 3), 3));
+
+ assertEquals(0xcede03, NB.decodeUInt24(b(0xce, 0xde, 3), 0));
+ assertEquals(0xbade03, NB.decodeUInt24(padb(3, 0xba, 0xde, 3), 3));
+
+ assertEquals(0x03bade, NB.decodeUInt24(b(3, 0xba, 0xde), 0));
+ assertEquals(0x03bade, NB.decodeUInt24(padb(3, 3, 0xba, 0xde), 3));
+
+ assertEquals(0xffffff, NB.decodeUInt24(b(0xff, 0xff, 0xff), 0));
+ assertEquals(0xffffff, NB.decodeUInt24(padb(3, 0xff, 0xff, 0xff), 3));
+ }
+
+ @Test
public void testDecodeInt32() {
assertEquals(0, NB.decodeInt32(b(0, 0, 0, 0), 0));
assertEquals(0, NB.decodeInt32(padb(3, 0, 0, 0, 0), 3));
@@ -198,6 +216,39 @@
}
@Test
+ public void testEncodeInt24() {
+ byte[] out = new byte[16];
+
+ prepareOutput(out);
+ NB.encodeInt24(out, 0, 0);
+ assertOutput(b(0, 0, 0), out, 0);
+
+ prepareOutput(out);
+ NB.encodeInt24(out, 3, 0);
+ assertOutput(b(0, 0, 0), out, 3);
+
+ prepareOutput(out);
+ NB.encodeInt24(out, 0, 3);
+ assertOutput(b(0, 0, 3), out, 0);
+
+ prepareOutput(out);
+ NB.encodeInt24(out, 3, 3);
+ assertOutput(b(0, 0, 3), out, 3);
+
+ prepareOutput(out);
+ NB.encodeInt24(out, 0, 0xc0deac);
+ assertOutput(b(0xc0, 0xde, 0xac), out, 0);
+
+ prepareOutput(out);
+ NB.encodeInt24(out, 3, 0xbadeac);
+ assertOutput(b(0xba, 0xde, 0xac), out, 3);
+
+ prepareOutput(out);
+ NB.encodeInt24(out, 3, -1);
+ assertOutput(b(0xff, 0xff, 0xff), out, 3);
+ }
+
+ @Test
public void testEncodeInt32() {
final byte[] out = new byte[16];
@@ -315,10 +366,24 @@
return r;
}
+ private static byte[] b(int a, int b, int c) {
+ return new byte[] { (byte) a, (byte) b, (byte) c };
+ }
+
private static byte[] b(final int a, final int b, final int c, final int d) {
return new byte[] { (byte) a, (byte) b, (byte) c, (byte) d };
}
+ private static byte[] padb(int len, int a, int b, int c) {
+ final byte[] r = new byte[len + 4];
+ for (int i = 0; i < len; i++)
+ r[i] = (byte) 0xaf;
+ r[len] = (byte) a;
+ r[len + 1] = (byte) b;
+ r[len + 2] = (byte) c;
+ return r;
+ }
+
private static byte[] padb(final int len, final int a, final int b,
final int c, final int d) {
final byte[] r = new byte[len + 4];
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/NB.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/NB.java
index 8536f1d..471a499 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/NB.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/NB.java
@@ -113,6 +113,24 @@
}
/**
+ * Convert sequence of 3 bytes (network byte order) into unsigned value.
+ *
+ * @param intbuf
+ * buffer to acquire the 3 bytes of data from.
+ * @param offset
+ * position within the buffer to begin reading from. This
+ * position and the next 2 bytes after it (for a total of 3
+ * bytes) will be read.
+ * @return signed integer value that matches the 24 bits read.
+ * @since 4.9
+ */
+ public static int decodeUInt24(byte[] intbuf, int offset) {
+ int r = (intbuf[offset] & 0xff) << 8;
+ r |= intbuf[offset + 1] & 0xff;
+ return (r << 8) | (intbuf[offset + 2] & 0xff);
+ }
+
+ /**
* Convert sequence of 4 bytes (network byte order) into signed value.
*
* @param intbuf
@@ -223,6 +241,29 @@
}
/**
+ * Write a 24 bit integer as a sequence of 3 bytes (network byte order).
+ *
+ * @param intbuf
+ * buffer to write the 3 bytes of data into.
+ * @param offset
+ * position within the buffer to begin writing to. This position
+ * and the next 2 bytes after it (for a total of 3 bytes) will be
+ * replaced.
+ * @param v
+ * the value to write.
+ * @since 4.9
+ */
+ public static void encodeInt24(byte[] intbuf, int offset, int v) {
+ intbuf[offset + 2] = (byte) v;
+ v >>>= 8;
+
+ intbuf[offset + 1] = (byte) v;
+ v >>>= 8;
+
+ intbuf[offset] = (byte) v;
+ }
+
+ /**
* Write a 32 bit integer as a sequence of 4 bytes (network byte order).
*
* @param intbuf
