diff options
Diffstat (limited to 'wifi/java/android/net/wifi/aware/TlvBufferUtils.java')
| -rw-r--r-- | wifi/java/android/net/wifi/aware/TlvBufferUtils.java | 125 |
1 files changed, 108 insertions, 17 deletions
diff --git a/wifi/java/android/net/wifi/aware/TlvBufferUtils.java b/wifi/java/android/net/wifi/aware/TlvBufferUtils.java index 29f10e932e48..b3b5b2903471 100644 --- a/wifi/java/android/net/wifi/aware/TlvBufferUtils.java +++ b/wifi/java/android/net/wifi/aware/TlvBufferUtils.java @@ -61,6 +61,7 @@ public class TlvBufferUtils { public static class TlvConstructor { private int mTypeSize; private int mLengthSize; + private ByteOrder mByteOrder = ByteOrder.BIG_ENDIAN; private byte[] mArray; private int mArrayLength; @@ -84,6 +85,20 @@ public class TlvBufferUtils { } mTypeSize = typeSize; mLengthSize = lengthSize; + mPosition = 0; + } + + /** + * Configure the TLV constructor to use a particular byte order. Should be + * {@link ByteOrder#BIG_ENDIAN} (the default at construction) or + * {@link ByteOrder#LITTLE_ENDIAN}. + * + * @return The constructor to facilitate chaining + * {@code ctr.putXXX(..).putXXX(..)}. + */ + public TlvConstructor setByteOrder(ByteOrder byteOrder) { + mByteOrder = byteOrder; + return this; } /** @@ -96,6 +111,7 @@ public class TlvBufferUtils { public TlvConstructor wrap(@Nullable byte[] array) { mArray = array; mArrayLength = (array == null) ? 0 : array.length; + mPosition = 0; return this; } @@ -109,6 +125,7 @@ public class TlvBufferUtils { public TlvConstructor allocate(int capacity) { mArray = new byte[capacity]; mArrayLength = capacity; + mPosition = 0; return this; } @@ -155,6 +172,18 @@ public class TlvBufferUtils { } /** + * Copies a raw byte into the TLV buffer - without a type or a length. + * + * @param b The byte to be inserted into the structure. + * @return The constructor to facilitate chaining {@code cts.putXXX(..).putXXX(..)}. + */ + public TlvConstructor putRawByte(byte b) { + checkRawLength(1); + mArray[mPosition++] = b; + return this; + } + + /** * Copies a byte array into the TLV with the indicated type. For an LV * formatted structure (i.e. typeLength=0 in {@link TlvConstructor * TlvConstructor(int, int)} ) the type field is ignored. @@ -193,6 +222,22 @@ public class TlvBufferUtils { } /** + * Copies a byte array into the TLV - without a type or a length. + * + * @param array The array to be copied (in full) into the TLV structure. + * @return The constructor to facilitate chaining + * {@code ctr.putXXX(..).putXXX(..)}. + */ + public TlvConstructor putRawByteArray(@Nullable byte[] array) { + if (array == null) return this; + + checkRawLength(array.length); + System.arraycopy(array, 0, mArray, mPosition, array.length); + mPosition += array.length; + return this; + } + + /** * Places a zero length element (i.e. Length field = 0) into the TLV. * For an LV formatted structure (i.e. typeLength=0 in * {@link TlvConstructor TlvConstructor(int, int)} ) the type field is @@ -221,7 +266,7 @@ public class TlvBufferUtils { public TlvConstructor putShort(int type, short data) { checkLength(2); addHeader(type, 2); - Memory.pokeShort(mArray, mPosition, data, ByteOrder.BIG_ENDIAN); + Memory.pokeShort(mArray, mPosition, data, mByteOrder); mPosition += 2; return this; } @@ -239,7 +284,7 @@ public class TlvBufferUtils { public TlvConstructor putInt(int type, int data) { checkLength(4); addHeader(type, 4); - Memory.pokeInt(mArray, mPosition, data, ByteOrder.BIG_ENDIAN); + Memory.pokeInt(mArray, mPosition, data, mByteOrder); mPosition += 4; return this; } @@ -294,18 +339,24 @@ public class TlvBufferUtils { } } + private void checkRawLength(int dataLength) { + if (mPosition + dataLength > mArrayLength) { + throw new BufferOverflowException(); + } + } + private void addHeader(int type, int length) { if (mTypeSize == 1) { mArray[mPosition] = (byte) type; } else if (mTypeSize == 2) { - Memory.pokeShort(mArray, mPosition, (short) type, ByteOrder.BIG_ENDIAN); + Memory.pokeShort(mArray, mPosition, (short) type, mByteOrder); } mPosition += mTypeSize; if (mLengthSize == 1) { mArray[mPosition] = (byte) length; } else if (mLengthSize == 2) { - Memory.pokeShort(mArray, mPosition, (short) length, ByteOrder.BIG_ENDIAN); + Memory.pokeShort(mArray, mPosition, (short) length, mByteOrder); } mPosition += mLengthSize; } @@ -330,13 +381,19 @@ public class TlvBufferUtils { public int length; /** + * Control of the endianess of the TLV element - true for big-endian, false for little- + * endian. + */ + public ByteOrder byteOrder = ByteOrder.BIG_ENDIAN; + + /** * The Value (V) field - a raw byte array representing the current TLV * element where the entry starts at {@link TlvElement#offset}. */ - public byte[] refArray; + private byte[] mRefArray; /** - * The offset to be used into {@link TlvElement#refArray} to access the + * The offset to be used into {@link TlvElement#mRefArray} to access the * raw data representing the current TLV element. */ public int offset; @@ -344,7 +401,7 @@ public class TlvBufferUtils { private TlvElement(int type, int length, @Nullable byte[] refArray, int offset) { this.type = type; this.length = length; - this.refArray = refArray; + mRefArray = refArray; this.offset = offset; if (offset + length > refArray.length) { @@ -353,6 +410,15 @@ public class TlvBufferUtils { } /** + * Return the raw byte array of the Value (V) field. + * + * @return The Value (V) field as a byte array. + */ + public byte[] getRawData() { + return Arrays.copyOfRange(mRefArray, offset, offset + length); + } + + /** * Utility function to return a byte representation of a TLV element of * length 1. Note: an attempt to call this function on a TLV item whose * {@link TlvElement#length} is != 1 will result in an exception. @@ -364,7 +430,7 @@ public class TlvBufferUtils { throw new IllegalArgumentException( "Accesing a byte from a TLV element of length " + length); } - return refArray[offset]; + return mRefArray[offset]; } /** @@ -379,7 +445,7 @@ public class TlvBufferUtils { throw new IllegalArgumentException( "Accesing a short from a TLV element of length " + length); } - return Memory.peekShort(refArray, offset, ByteOrder.BIG_ENDIAN); + return Memory.peekShort(mRefArray, offset, byteOrder); } /** @@ -394,7 +460,7 @@ public class TlvBufferUtils { throw new IllegalArgumentException( "Accesing an int from a TLV element of length " + length); } - return Memory.peekInt(refArray, offset, ByteOrder.BIG_ENDIAN); + return Memory.peekInt(mRefArray, offset, byteOrder); } /** @@ -403,7 +469,7 @@ public class TlvBufferUtils { * @return String repersentation of the current TLV element. */ public String getString() { - return new String(refArray, offset, length); + return new String(mRefArray, offset, length); } } @@ -413,6 +479,7 @@ public class TlvBufferUtils { public static class TlvIterable implements Iterable<TlvElement> { private int mTypeSize; private int mLengthSize; + private ByteOrder mByteOrder = ByteOrder.BIG_ENDIAN; private byte[] mArray; private int mArrayLength; @@ -440,6 +507,13 @@ public class TlvBufferUtils { } /** + * Configure the TLV iterator to use little-endian byte ordering. + */ + public void setByteOrder(ByteOrder byteOrder) { + mByteOrder = byteOrder; + } + + /** * Prints out a parsed representation of the TLV-formatted byte array. * Whenever possible bytes, shorts, and integer are printed out (for * fields whose length is 1, 2, or 4 respectively). @@ -486,7 +560,7 @@ public class TlvBufferUtils { public List<byte[]> toList() { List<byte[]> list = new ArrayList<>(); for (TlvElement tlv : this) { - list.add(Arrays.copyOfRange(tlv.refArray, tlv.offset, tlv.offset + tlv.length)); + list.add(Arrays.copyOfRange(tlv.mRefArray, tlv.offset, tlv.offset + tlv.length)); } return list; @@ -516,7 +590,7 @@ public class TlvBufferUtils { if (mTypeSize == 1) { type = mArray[mOffset]; } else if (mTypeSize == 2) { - type = Memory.peekShort(mArray, mOffset, ByteOrder.BIG_ENDIAN); + type = Memory.peekShort(mArray, mOffset, mByteOrder); } mOffset += mTypeSize; @@ -524,11 +598,12 @@ public class TlvBufferUtils { if (mLengthSize == 1) { length = mArray[mOffset]; } else if (mLengthSize == 2) { - length = Memory.peekShort(mArray, mOffset, ByteOrder.BIG_ENDIAN); + length = Memory.peekShort(mArray, mOffset, mByteOrder); } mOffset += mLengthSize; TlvElement tlv = new TlvElement(type, length, mArray, mOffset); + tlv.byteOrder = mByteOrder; mOffset += length; return tlv; } @@ -543,7 +618,8 @@ public class TlvBufferUtils { /** * Validates that a (T)LV array is constructed correctly. I.e. that its specified Length - * fields correctly fill the specified length (and do not overshoot). + * fields correctly fill the specified length (and do not overshoot). Uses big-endian + * byte ordering. * * @param array The (T)LV array to verify. * @param typeSize The size (in bytes) of the type field. Valid values are 0, 1, or 2. @@ -551,6 +627,22 @@ public class TlvBufferUtils { * @return A boolean indicating whether the array is valid (true) or invalid (false). */ public static boolean isValid(@Nullable byte[] array, int typeSize, int lengthSize) { + return isValidEndian(array, typeSize, lengthSize, ByteOrder.BIG_ENDIAN); + } + + /** + * Validates that a (T)LV array is constructed correctly. I.e. that its specified Length + * fields correctly fill the specified length (and do not overshoot). + * + * @param array The (T)LV array to verify. + * @param typeSize The size (in bytes) of the type field. Valid values are 0, 1, or 2. + * @param lengthSize The size (in bytes) of the length field. Valid values are 1 or 2. + * @param byteOrder The endianness of the byte array: {@link ByteOrder#BIG_ENDIAN} or + * {@link ByteOrder#LITTLE_ENDIAN}. + * @return A boolean indicating whether the array is valid (true) or invalid (false). + */ + public static boolean isValidEndian(@Nullable byte[] array, int typeSize, int lengthSize, + ByteOrder byteOrder) { if (typeSize < 0 || typeSize > 2) { throw new IllegalArgumentException( "Invalid arguments - typeSize must be 0, 1, or 2: typeSize=" + typeSize); @@ -569,8 +661,7 @@ public class TlvBufferUtils { if (lengthSize == 1) { nextTlvIndex += lengthSize + array[nextTlvIndex]; } else { - nextTlvIndex += lengthSize + Memory.peekShort(array, nextTlvIndex, - ByteOrder.BIG_ENDIAN); + nextTlvIndex += lengthSize + Memory.peekShort(array, nextTlvIndex, byteOrder); } } |