From ed4fd1002b17042dce1fb944e5e53cbbd55bbd0a Mon Sep 17 00:00:00 2001 From: Christian Basler Date: Sun, 12 Jun 2016 20:53:05 +0200 Subject: [PATCH] Improved uint reading --- .../ch/dissem/bitmessage/utils/Decode.java | 102 +++++++++--------- 1 file changed, 54 insertions(+), 48 deletions(-) diff --git a/core/src/main/java/ch/dissem/bitmessage/utils/Decode.java b/core/src/main/java/ch/dissem/bitmessage/utils/Decode.java index fb2f3c8..c15f397 100644 --- a/core/src/main/java/ch/dissem/bitmessage/utils/Decode.java +++ b/core/src/main/java/ch/dissem/bitmessage/utils/Decode.java @@ -27,30 +27,29 @@ import static ch.dissem.bitmessage.utils.AccessCounter.inc; * https://bitmessage.org/wiki/Protocol_specification#Common_structures */ public class Decode { - public static byte[] shortVarBytes(InputStream stream, AccessCounter counter) throws IOException { - int length = uint16(stream, counter); - return bytes(stream, length, counter); + public static byte[] shortVarBytes(InputStream in, AccessCounter counter) throws IOException { + int length = uint16(in, counter); + return bytes(in, length, counter); } - public static byte[] varBytes(InputStream stream) throws IOException { - int length = (int) varInt(stream, null); - return bytes(stream, length, null); + public static byte[] varBytes(InputStream in) throws IOException { + return varBytes(in, null); } - public static byte[] varBytes(InputStream stream, AccessCounter counter) throws IOException { - int length = (int) varInt(stream, counter); - return bytes(stream, length, counter); + public static byte[] varBytes(InputStream in, AccessCounter counter) throws IOException { + int length = (int) varInt(in, counter); + return bytes(in, length, counter); } - public static byte[] bytes(InputStream stream, int count) throws IOException { - return bytes(stream, count, null); + public static byte[] bytes(InputStream in, int count) throws IOException { + return bytes(in, count, null); } - public static byte[] bytes(InputStream stream, int count, AccessCounter counter) throws IOException { + public static byte[] bytes(InputStream in, int count, AccessCounter counter) throws IOException { byte[] result = new byte[count]; int off = 0; while (off < count) { - int read = stream.read(result, off, count - off); + int read = in.read(result, off, count - off); if (read < 0) { throw new IOException("Unexpected end of stream, wanted to read " + count + " bytes but only got " + off); } @@ -60,87 +59,94 @@ public class Decode { return result; } - public static long[] varIntList(InputStream stream) throws IOException { - int length = (int) varInt(stream); + public static long[] varIntList(InputStream in) throws IOException { + int length = (int) varInt(in); long[] result = new long[length]; for (int i = 0; i < length; i++) { - result[i] = varInt(stream); + result[i] = varInt(in); } return result; } - public static long varInt(InputStream stream) throws IOException { - return varInt(stream, null); + public static long varInt(InputStream in) throws IOException { + return varInt(in, null); } - public static long varInt(InputStream stream, AccessCounter counter) throws IOException { - int first = stream.read(); + public static long varInt(InputStream in, AccessCounter counter) throws IOException { + int first = in.read(); inc(counter); switch (first) { case 0xfd: - return uint16(stream, counter); + return uint16(in, counter); case 0xfe: - return uint32(stream, counter); + return uint32(in, counter); case 0xff: - return int64(stream, counter); + return int64(in, counter); default: return first; } } - public static int uint8(InputStream stream) throws IOException { - return stream.read(); + public static int uint8(InputStream in) throws IOException { + return in.read(); } - public static int uint16(InputStream stream) throws IOException { - return uint16(stream, null); + public static int uint16(InputStream in) throws IOException { + return uint16(in, null); } - public static int uint16(InputStream stream, AccessCounter counter) throws IOException { + public static int uint16(InputStream in, AccessCounter counter) throws IOException { inc(counter, 2); - return stream.read() * 256 + stream.read(); + return in.read() << 8 | in.read(); } - public static long uint32(InputStream stream) throws IOException { - return uint32(stream, null); + public static long uint32(InputStream in) throws IOException { + return uint32(in, null); } - public static long uint32(InputStream stream, AccessCounter counter) throws IOException { + public static long uint32(InputStream in, AccessCounter counter) throws IOException { inc(counter, 4); - return stream.read() * 16777216L + stream.read() * 65536L + stream.read() * 256L + stream.read(); + return in.read() << 24 | in.read() << 16 | in.read() << 8 | in.read(); } - public static long uint32(ByteBuffer buffer) { - return buffer.get() * 16777216L + buffer.get() * 65536L + buffer.get() * 256L + buffer.get(); + public static long uint32(ByteBuffer in) { + return u(in.get()) << 24 | u(in.get()) << 16 | u(in.get()) << 8 | u(in.get()); } - public static int int32(InputStream stream) throws IOException { - return int32(stream, null); + public static int int32(InputStream in) throws IOException { + return int32(in, null); } - public static int int32(InputStream stream, AccessCounter counter) throws IOException { + public static int int32(InputStream in, AccessCounter counter) throws IOException { inc(counter, 4); - return ByteBuffer.wrap(bytes(stream, 4)).getInt(); + return ByteBuffer.wrap(bytes(in, 4)).getInt(); } - public static long int64(InputStream stream) throws IOException { - return int64(stream, null); + public static long int64(InputStream in) throws IOException { + return int64(in, null); } - public static long int64(InputStream stream, AccessCounter counter) throws IOException { + public static long int64(InputStream in, AccessCounter counter) throws IOException { inc(counter, 8); - return ByteBuffer.wrap(bytes(stream, 8)).getLong(); + return ByteBuffer.wrap(bytes(in, 8)).getLong(); } - public static String varString(InputStream stream) throws IOException { - return varString(stream, null); + public static String varString(InputStream in) throws IOException { + return varString(in, null); } - public static String varString(InputStream stream, AccessCounter counter) throws IOException { - int length = (int) varInt(stream, counter); + public static String varString(InputStream in, AccessCounter counter) throws IOException { + int length = (int) varInt(in, counter); // FIXME: technically, it says the length in characters, but I think this one might be correct // otherwise it will get complicated, as we'll need to read UTF-8 char by char... - return new String(bytes(stream, length, counter), "utf-8"); + return new String(bytes(in, length, counter), "utf-8"); + } + + /** + * Returns the given byte as if it were unsigned. + */ + private static int u(byte b) { + return b & 0xFF; } }