1 files changed, 222 insertions, 0 deletions
diff --git a/lib/DDHidKeyboardBarcodeScanner.m b/lib/DDHidKeyboardBarcodeScanner.m
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+++ b/lib/DDHidKeyboardBarcodeScanner.m
@@ -0,0 +1,222 @@
+/*
+ * Copyright (c) 2007 Dave Dribin, Lucas Newman
+ * 
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#import "DDHidKeyboardBarcodeScanner.h"
+#import "DDHidElement.h"
+#import "DDHidUsage.h"
+#import "DDHidQueue.h"
+#import "DDHidEvent.h"
+#include <IOKit/hid/IOHIDUsageTables.h>
+
+@interface DDHidKeyboardBarcodeScanner (DDHidKeyboardBarcodeDelegate)
+
+- (void) ddhidKeyboardBarcodeScanner: (DDHidKeyboardBarcodeScanner *) keyboardBarcodeScanner
+                          gotBarcode: (NSString *) barcode;
+
+@end
+
+@interface DDHidKeyboardBarcodeScanner (Private)
+
+- (void) initKeyboardElements: (NSArray *) elements;
+- (void) ddhidQueueHasEvents: (DDHidQueue *) hidQueue;
+- (void) processBarcodeDigit: (unsigned) usageId;
+- (void) clearAccumulatedInput;
+- (void) invalidateBarcodeInputTimer;
+
+@end
+
+@implementation DDHidKeyboardBarcodeScanner
+
++ (NSArray *) allPossibleKeyboardBarcodeScanners;
+{
+    return [DDHidDevice allDevicesMatchingUsagePage: kHIDPage_GenericDesktop
+                                            usageId: kHIDUsage_GD_Keyboard
+                                          withClass: self
+                                  skipZeroLocations: YES];
+}
+
+- (id) initWithDevice: (io_object_t) device error: (NSError **) error_;
+{
+    self = [super initWithDevice: device error: error_];
+    if (self == nil)
+        return nil;
+    
+    mKeyElements = [[NSMutableArray alloc] init];
+    mAccumulatedDigits = [[NSMutableString alloc] init];
+    mBarcodeInputTimer = nil;
+    
+    if ([[self productName] rangeOfString:@"Apple"].location != NSNotFound || [[self productName] rangeOfString:@"Internal"].location != NSNotFound)
+        mIsLikelyKeyboardBarcodeScanner = NO;
+    else
+        mIsLikelyKeyboardBarcodeScanner = YES; // if we see invalid barcodes, we can change our mind
+    
+    [self initKeyboardElements: [self elements]];
+    
+    return self;
+}
+
+//=========================================================== 
+// dealloc
+//=========================================================== 
+- (void) dealloc
+{
+    [self invalidateBarcodeInputTimer];
+    [mKeyElements release];
+    [mAccumulatedDigits release];
+    
+    mKeyElements = nil;
+    mAccumulatedDigits = nil;
+    [super dealloc];
+}
+
+#pragma mark -
+#pragma mark Keyboard Elements
+
+- (NSArray *) keyElements;
+{
+    return mKeyElements;
+}
+
+- (unsigned) numberOfKeys;
+{
+    return [mKeyElements count];
+}
+
+- (void) addElementsToQueue: (DDHidQueue *) queue;
+{
+    [queue addElements: mKeyElements];
+}
+
+#pragma mark -
+#pragma mark Asynchronous Notification
+
+- (void) setDelegate: (id) delegate;
+{
+    mDelegate = delegate;
+}
+
+- (void) addElementsToDefaultQueue;
+{
+    [self addElementsToQueue: mDefaultQueue];
+}
+
+#pragma mark -
+#pragma mark Properties
+
+- (BOOL) isLikelyKeyboardBarcodeScanner;
+{
+    return mIsLikelyKeyboardBarcodeScanner;
+}
+
+@end
+
+@implementation DDHidKeyboardBarcodeScanner (DDHidKeyboardDelegate)
+
+- (void) ddhidKeyboardBarcodeScanner: (DDHidKeyboardBarcodeScanner *) keyboardBarcodeScanner
+                          gotBarcode: (NSString *) barcode;
+{
+    if ([mDelegate respondsToSelector: _cmd])
+        [mDelegate ddhidKeyboardBarcodeScanner: keyboardBarcodeScanner gotBarcode: barcode];
+}
+
+@end
+
+@implementation DDHidKeyboardBarcodeScanner (Private)
+
+- (void) initKeyboardElements: (NSArray *) elements;
+{
+    NSEnumerator * e = [elements objectEnumerator];
+    DDHidElement * element;
+    while ((element = [e nextObject]))
+    {
+        unsigned usagePage = [[element usage] usagePage];
+        unsigned usageId = [[element usage] usageId];
+        if (usagePage == kHIDPage_KeyboardOrKeypad)
+        {
+            if ((usageId >= kHIDUsage_KeyboardA) && (usageId <= kHIDUsage_Keyboard0))
+            {
+                [mKeyElements addObject: element];
+            }
+        }
+        NSArray * subElements = [element elements];
+        if (subElements != nil)
+            [self initKeyboardElements: subElements];
+    }
+}
+
+- (void) ddhidQueueHasEvents: (DDHidQueue *) hidQueue;
+{
+    DDHidEvent * event;
+    while ((event = [hidQueue nextEvent]))
+    {
+        DDHidElement * element = [self elementForCookie: [event elementCookie]];
+        unsigned usageId = [[element usage] usageId];
+        SInt32 value = [event value];
+        if (value == 1) // key down
+            [self processBarcodeDigit: usageId];
+    }
+}
+
+#define UPC_A_BARCODE_LENGTH (12)
+#define BARCODE_INPUT_TIMEOUT (0.5)
+   
+- (void) processBarcodeDigit: (unsigned) usageId;
+{
+    if (usageId <= kHIDUsage_KeyboardZ || usageId >= kHIDUsage_KeyboardCapsLock) { // an alphabetic key was pressed => probably not a barcode scanner
+        [self willChangeValueForKey:@"isLikelyKeyboardBarcodeScanner"];
+        mIsLikelyKeyboardBarcodeScanner = NO;
+        [self didChangeValueForKey:@"isLikelyKeyboardBarcodeScanner"];
+        
+        [self clearAccumulatedInput];
+        return;
+    }
+    
+    if (!mBarcodeInputTimer) // schedule a timer to make sure we get the rest of the digits in a timely manner
+        mBarcodeInputTimer = [[NSTimer scheduledTimerWithTimeInterval:BARCODE_INPUT_TIMEOUT target:self selector:@selector(fireBarcodeInputTimeout:) userInfo:nil repeats:NO] retain];
+    
+    [mAccumulatedDigits appendString:[NSString stringWithFormat:@"%d", (usageId + 1) % 10]];
+}
+
+- (void) fireBarcodeInputTimeout: (NSTimer *) timer;
+{
+    if ([mAccumulatedDigits length] >= UPC_A_BARCODE_LENGTH)
+        [self ddhidKeyboardBarcodeScanner: self gotBarcode: [[mAccumulatedDigits copy] autorelease]];
+    [self clearAccumulatedInput];
+}
+
+- (void) clearAccumulatedInput;
+{
+    [mAccumulatedDigits deleteCharactersInRange:NSMakeRange(0, [mAccumulatedDigits length])];
+    
+    [self invalidateBarcodeInputTimer];
+}
+
+- (void) invalidateBarcodeInputTimer;
+{
+    [mBarcodeInputTimer invalidate];
+    [mBarcodeInputTimer release];
+    mBarcodeInputTimer = nil;
+}
+
+@end