input: replace -1 as default axis limit with NO_AXIS_LIMIT define.

This allows easier refacturing of the coordinate limit handling. Grepping for
-1 is boring.

4 files changed, 30 insertions, 17 deletions

diff --git a/Xi/exevents.c b/Xi/exevents.c
index 761950ead..d0c10d9da 100644
--- a/Xi/exevents.c
+++ b/Xi/exevents.c
@@ -1153,13 +1153,22 @@ InitProximityClassDeviceStruct(DeviceIntPtr dev)
     return TRUE;
 }
 
+/**
+ * Initialise the device's valuators. The memory must already be allocated,
+ * this function merely inits the matching axis (specified through axnum) to
+ * sane values.
+ *
+ * It is a condition that (minval < maxval).
+ *
+ * @see InitValuatorClassDeviceStruct
+ */
 _X_EXPORT void
 InitValuatorAxisStruct(DeviceIntPtr dev, int axnum, int minval, int maxval,
 		       int resolution, int min_res, int max_res)
 {
     AxisInfoPtr ax;
-  
-    if (!dev || !dev->valuator)
+
+    if (!dev || !dev->valuator || minval > maxval)
         return;
 
     ax = dev->valuator->axes + axnum;
diff --git a/dix/devices.c b/dix/devices.c
index 37feb34a3..abd3cb6d2 100644
--- a/dix/devices.c
+++ b/dix/devices.c
@@ -1187,7 +1187,8 @@ InitValuatorClassDeviceStruct(DeviceIntPtr dev, int numAxes,
         AllocateMotionHistory(dev);
 
     for (i=0; i<numAxes; i++) {
-        InitValuatorAxisStruct(dev, i, -1, -1, 0, 0, 0);
+        InitValuatorAxisStruct(dev, i, NO_AXIS_LIMITS, NO_AXIS_LIMITS,
+                               0, 0, 0);
 	valc->axisVal[i]=0;
     }
     return TRUE;
@@ -1203,10 +1204,10 @@ InitAbsoluteClassDeviceStruct(DeviceIntPtr dev)
         return FALSE;
 
     /* we don't do anything sensible with these, but should */
-    abs->min_x = -1;
-    abs->min_y = -1;
-    abs->max_x = -1;
-    abs->max_y = -1;
+    abs->min_x = NO_AXIS_LIMITS;
+    abs->min_y = NO_AXIS_LIMITS;
+    abs->max_x = NO_AXIS_LIMITS;
+    abs->max_y = NO_AXIS_LIMITS;
     abs->flip_x = 0;
     abs->flip_y = 0;
     abs->rotation = 0;
@@ -1214,8 +1215,8 @@ InitAbsoluteClassDeviceStruct(DeviceIntPtr dev)
 
     abs->offset_x = 0;
     abs->offset_y = 0;
-    abs->width = -1;
-    abs->height = -1;
+    abs->width = NO_AXIS_LIMITS;
+    abs->height = NO_AXIS_LIMITS;
     abs->following = 0;
     abs->screen = 0;
 
diff --git a/dix/getevents.c b/dix/getevents.c
index e9c1db0f5..a358bb3e9 100644
--- a/dix/getevents.c
+++ b/dix/getevents.c
@@ -358,14 +358,15 @@ clipAxis(DeviceIntPtr pDev, int axisNum, int *val)
 {
     AxisInfoPtr axes = pDev->valuator->axes + axisNum;
 
-    /* Don't clip if min_value and max_value are the same, or if an invalid
-       range is specified. */
-    if(axes->min_value < axes->max_value) {
-        if (*val < axes->min_value)
-            *val = axes->min_value;
-        if (*val > axes->max_value)
-            *val = axes->max_value;
-    }
+    /* InitValuatoraAxisStruct ensures that (min < max) */
+
+    if (axes->min_value != NO_AXIS_LIMITS &&
+            *val < axis->min_value)
+        *val = axes->min_value;
+
+    if (axes->max_value != NO_AXIS_LIMITS &&
+            *val > axes->max_value)
+        *val = axes->max_value;
 }
 
 /**
diff --git a/include/input.h b/include/input.h
index 10dadfebc..ec6ac90e1 100644
--- a/include/input.h
+++ b/include/input.h
@@ -63,6 +63,8 @@ SOFTWARE.
 #define POINTER_ABSOLUTE (1 << 2)
 #define POINTER_ACCELERATE (1 << 3)
 
+#define NO_AXIS_LIMITS -1
+
 #define MAP_LENGTH	256
 #define DOWN_LENGTH	32	/* 256/8 => number of bytes to hold 256 bits */
 #define NullGrab ((GrabPtr)NULL)