diff options
Diffstat (limited to 'libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/tls/ByteQueue.java')
-rw-r--r-- | libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/tls/ByteQueue.java | 153 |
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; + } +} |