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Improve VarInt: simplify, fix some minor bugs and increase test coverage.

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This commit is contained in:
Mike Hearn 2011-03-13 21:29:25 +00:00
parent debd034c71
commit a504328044
2 changed files with 27 additions and 18 deletions
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21
src/com/google/bitcoin/core/VarInt.java
View File

@ -16,6 +16,8 @@
package com.google.bitcoin.core;
import static com.google.bitcoin.core.Utils.isLessThanUnsigned;
public class VarInt {
public final long value;
@ -44,13 +46,12 @@ public class VarInt {
}
public int getSizeInBytes() {
// Java doesn't have the actual value of MAX_INT, as all types in Java
// are signed *headsmash*.
if (value < 253)
// Java doesn't have the actual value of MAX_INT, as all types in Java are signed.
if (isLessThanUnsigned(value, 253))
return 1;
else if (value <= 65536)
else if (isLessThanUnsigned(value, 65536))
return 3; // 1 marker + 2 data bytes
else if (value <= 4294967295L)
else if (isLessThanUnsigned(value, 4294967296L))
return 5; // 1 marker + 4 data bytes
else
return 9; // 1 marker + 8 data bytes
@ -63,11 +64,11 @@ public class VarInt {
public byte[] encodeBE() {
if (Utils.isLessThanUnsigned(value, 253)) {
if (isLessThanUnsigned(value, 253)) {
return new byte[] { (byte)value };
} else if (Utils.isLessThanUnsigned(value, 65536)) {
} else if (isLessThanUnsigned(value, 65536)) {
return new byte[] { (byte) 253, (byte) (value), (byte) (value >> 8) };
} else if (Utils.isLessThanUnsigned(value, 4294967295L)) {
} else if (isLessThanUnsigned(value, 4294967295L)) {
byte[] bytes = new byte[5];
bytes[0] = (byte) 254;
Utils.uint32ToByteArrayLE(value, bytes, 1);
@ -75,8 +76,8 @@ public class VarInt {
} else {
byte[] bytes = new byte[9];
bytes[0] = (byte) 255;
Utils.uint32ToByteArrayLE(value & 0xFFFFFFFF, bytes, 1);
Utils.uint32ToByteArrayLE(value >> 32, bytes, 5);
Utils.uint32ToByteArrayLE(value, bytes, 1);
Utils.uint32ToByteArrayLE(value >>> 32, bytes, 5);
return bytes;
}
}

24
tests/com/google/bitcoin/core/VarIntTest.java
View File

@ -19,25 +19,33 @@ package com.google.bitcoin.core;
import junit.framework.TestCase;
public class VarIntTest extends TestCase {
public void testVarInts() throws Exception {
VarInt a;
// Bytes
a = new VarInt(10);
public void testBytes() throws Exception {
VarInt a = new VarInt(10);
assertEquals(1, a.getSizeInBytes());
assertEquals(1, a.encode().length);
assertEquals(10, new VarInt(a.encode(), 0).value);
}
// Shorts
a = new VarInt(64000);
public void testShorts() throws Exception {
VarInt a = new VarInt(64000);
assertEquals(3, a.getSizeInBytes());
assertEquals(3, a.encode().length);
assertEquals(64000, new VarInt(a.encode(), 0).value);
}
a = new VarInt(0xAABBCCDDL);
public void testInts() throws Exception {
VarInt a = new VarInt(0xAABBCCDDL);
assertEquals(5, a.getSizeInBytes());
assertEquals(5, a.encode().length);
byte[] bytes = a.encode();
assertEquals(0xAABBCCDDL, 0xFFFFFFFFL & new VarInt(bytes, 0).value);
}
public void testLong() throws Exception {
VarInt a = new VarInt(0xCAFEBABEDEADBEEFL);
assertEquals(9, a.getSizeInBytes());
assertEquals(9, a.encode().length);
byte[] bytes = a.encode();
assertEquals(0xCAFEBABEDEADBEEFL, new VarInt(bytes, 0).value);
}
}