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-rw-r--r--libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/tls/ByteQueue.java153
1 files changed, 153 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/tls/ByteQueue.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/tls/ByteQueue.java
new file mode 100644
index 000000000..d3cf8bf5d
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/tls/ByteQueue.java
@@ -0,0 +1,153 @@
+package org.spongycastle.crypto.tls;
+
+/**
+ * A queue for bytes. This file could be more optimized.
+ */
+public class ByteQueue
+{
+ /**
+ * @return The smallest number which can be written as 2^x which is bigger than i.
+ */
+ public static final int nextTwoPow(int i)
+ {
+ /*
+ * This code is based of a lot of code I found on the Internet which mostly
+ * referenced a book called "Hacking delight".
+ */
+ i |= (i >> 1);
+ i |= (i >> 2);
+ i |= (i >> 4);
+ i |= (i >> 8);
+ i |= (i >> 16);
+ return i + 1;
+ }
+
+ /**
+ * The initial size for our buffer.
+ */
+ private static final int DEFAULT_CAPACITY = 1024;
+
+ /**
+ * The buffer where we store our data.
+ */
+ private byte[] databuf;;
+
+ /**
+ * How many bytes at the beginning of the buffer are skipped.
+ */
+ private int skipped = 0;
+
+ /**
+ * How many bytes in the buffer are valid data.
+ */
+ private int available = 0;
+
+ public ByteQueue()
+ {
+ this(DEFAULT_CAPACITY);
+ }
+
+ public ByteQueue(int capacity)
+ {
+ databuf = new byte[capacity];
+ }
+
+ /**
+ * Read data from the buffer.
+ *
+ * @param buf The buffer where the read data will be copied to.
+ * @param offset How many bytes to skip at the beginning of buf.
+ * @param len How many bytes to read at all.
+ * @param skip How many bytes from our data to skip.
+ */
+ public void read(byte[] buf, int offset, int len, int skip)
+ {
+ if ((available - skip) < len)
+ {
+ throw new TlsRuntimeException("Not enough data to read");
+ }
+ if ((buf.length - offset) < len)
+ {
+ throw new TlsRuntimeException("Buffer size of " + buf.length
+ + " is too small for a read of " + len + " bytes");
+ }
+ System.arraycopy(databuf, skipped + skip, buf, offset, len);
+ }
+
+ /**
+ * Add some data to our buffer.
+ *
+ * @param buf A byte-array to read data from.
+ * @param off How many bytes to skip at the beginning of the array.
+ * @param len How many bytes to read from the array.
+ */
+ public void addData(byte[] buf, int off, int len)
+ {
+ if ((skipped + available + len) > databuf.length)
+ {
+ int desiredSize = ByteQueue.nextTwoPow(available + len);
+ if (desiredSize > databuf.length)
+ {
+ byte[] tmp = new byte[desiredSize];
+ System.arraycopy(databuf, skipped, tmp, 0, available);
+ databuf = tmp;
+ }
+ else
+ {
+ System.arraycopy(databuf, skipped, databuf, 0, available);
+ }
+ skipped = 0;
+ }
+
+ System.arraycopy(buf, off, databuf, skipped + available, len);
+ available += len;
+ }
+
+ /**
+ * Remove some bytes from our data from the beginning.
+ *
+ * @param i How many bytes to remove.
+ */
+ public void removeData(int i)
+ {
+ if (i > available)
+ {
+ throw new TlsRuntimeException("Cannot remove " + i + " bytes, only got " + available);
+ }
+
+ /*
+ * Skip the data.
+ */
+ available -= i;
+ skipped += i;
+ }
+
+ /**
+ * Remove data from the buffer.
+ *
+ * @param buf The buffer where the removed data will be copied to.
+ * @param off How many bytes to skip at the beginning of buf.
+ * @param len How many bytes to read at all.
+ * @param skip How many bytes from our data to skip.
+ */
+ public void removeData(byte[] buf, int off, int len, int skip)
+ {
+ read(buf, off, len, skip);
+ removeData(skip + len);
+ }
+
+ public byte[] removeData(int len, int skip)
+ {
+ byte[] buf = new byte[len];
+ removeData(buf, 0, len, skip);
+ return buf;
+ }
+
+ /**
+ * @return The number of bytes which are available in this buffer.
+ */
+ public int size()
+ {
+ return available;
+ }
+}