localconnectivityservice/generichid/inc/hiditem.h
branchRCL_3
changeset 22 52a167391590
parent 0 c3e98f10fcf4
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/localconnectivityservice/generichid/inc/hiditem.h	Wed Sep 01 12:20:40 2010 +0100
@@ -0,0 +1,198 @@
+/*
+* Copyright (c) 2005-2007 Nokia Corporation and/or its subsidiary(-ies).
+* All rights reserved.
+* This component and the accompanying materials are made available
+* under the terms of "Eclipse Public License v1.0"
+* which accompanies this distribution, and is available
+* at the URL "http://www.eclipse.org/legal/epl-v10.html".
+*
+* Initial Contributors:
+* Nokia Corporation - initial contribution.
+*
+* Contributors:
+*
+* Description:  BTHid item
+*
+*/
+
+
+#ifndef T_ITEM_H
+#define T_ITEM_H
+
+#include <e32std.h>
+
+/**
+ * HID item class
+ * A HID report descriptor is comprised of a sequence of "items"
+ * that provide information about the device.  Items consist of a
+ * header and zero or more bytes of data.  The header contains the item
+ * type (main/global/local), an item "tag" (subtype) and the item size.
+ * Items can be "short" (containing a maximum of 4 bytes of data) or
+ * "long" (a maximum of 255 bytes of data).
+
+ * A TItem represents a single HID report descriptor item. It is
+ * constructed from an eight bit non-modifiable (Symbian-) descriptor,
+ * which is assumed to contain report (HID-) descriptor data.
+ *
+ * @lib generichid.lib
+ * @since S60 v5.0
+ */
+class TItem
+    {
+public:
+    /**
+     * The possible item types: main, global or local.  Item type is
+     * a two-bit field -- the 11b value is reserved for "long items", which
+     * are only used for vendor-specific commands.
+     */
+    enum TItemType
+        {
+        EMain = 0,    //!< Input, output, feature and begin or end collection
+        EGlobal = 1,  //!< Global item items affect all subsequent fields
+        ELocal = 2,   //!< Local items only persist until the next main item
+        EReserved = 3 //!< No defined use in the current HID standard (v1.11)
+        };
+
+public:
+
+    /**
+     * The constructor takes a an eight bit non-modifiable (Symbian-)
+     * descriptor containing report (HID-) descriptor data.
+     * The item tag, type, data size and offset are calculated here.
+     *
+     * @since S60 v5.0
+     * @param aRawData The raw item data, represented as a Symbian
+     * descriptor. The item data is assumed to be at the beginning of the
+     * descriptor. The size of the TDesC8 may be greater than the size
+     * of the item, as the item size will be calculated from the raw HID
+     * descriptor data.  Of course, the TDesC8 should be at least as
+     * long as the raw item data.
+     */
+    TItem(const TDesC8& aRawData);
+
+    /**
+     * DataSize() returns the size of the item data in bytes. This
+     * is the total item size minus the size of any header information.
+     * (A short item header is a single byte, a long item header is
+     * three bytes long.)
+     *
+     * @since S60 v5.0
+     * @return The size, in bytes, of the item data. Range 0-255.
+     */
+    TInt DataSize() const;
+
+    /**
+     * Tag() returns the tag (subtype) value for this item.
+     *
+     * @since S60 v5.0
+     * @return The item tag.
+     */
+    TInt Tag() const;
+
+    /**
+     * Data() returns the data associated with the item, represented as a
+     * 32-bit unsigned integer.  This is only meaningful if the data length
+     * is less than 4 bytes.
+     *
+     * @since S60 v5.0
+     * @return The item data as a 32-bit unsigned integer.
+     */
+    TUint32 Data() const;
+
+    /**
+     * SignedData() returns the data associated with the item,
+     * represented as a 32-bit signed integer.  This is only
+     * meaningful if the data length is less than 4 bytes.
+     *
+     * @since S60 v5.0
+     * @return The item data as a 32-bit signed integer.
+     */
+    TInt32 SignedData() const;
+
+    /**
+     * Returns the byte at the given offset within the item data block.     
+     *
+     * @since S60 v5.0
+     * @param aIndex The index within the data block for the current tag.
+     * @return The data at the specified index.
+     */
+    TUint8 operator[](TInt aIndex) const;
+
+    /**
+     * Type() returns the item type (e.g. "global").
+     *
+     * @since S60 v5.0     
+     * @return The item type.
+     */
+    TItemType Type() const;
+
+    /**
+     * Check if item is main
+     *
+     * @since S60 v5.0
+     * @return ETrue if item type is "main"
+     */
+    TBool IsMain() const;
+
+    /**
+     * Check if item is local
+     *
+     * @since S60 v5.0
+     * @return ETrue if item type is "local"
+     */
+    TBool IsLocal() const;
+
+    /**
+     * Check if item is global
+     *
+     * @since S60 v5.0
+     * @return ETrue if item type is "global"
+     */
+    TBool IsGlobal() const;
+
+    /**
+     * Check if item is global
+     *
+     * @since S60 v5.0
+     * @return ETrue if this is a long item
+     */
+    TBool IsLong() const;
+
+    /**
+     * ItemSize() returns the total size of this item, including the
+     * header data.
+     *
+     * @since S60 v5.0
+     * @return The total size of this item, in bytes.
+     */
+    TInt ItemSize() const;
+
+private:
+    /**
+     * Pointer to the raw report descriptor data
+     */
+    TPtrC8 iRawData;
+
+    /**
+     * Item data size
+     */
+
+    TInt iSize;
+    /**
+     * Item tag value
+     */
+    TInt iTag;
+
+    /**
+     * Offset in bytes of the data block
+     */
+    TInt iDataOffset;
+
+    /**
+     * Item type
+     */
+    TItemType iType;
+    };
+
+#endif
+