[PATCH 4/6] Xi: add XATOM_FLOAT to server-defined properties.

[Peter Hutterer]

This property is used to denote type float for input properties. Such
properties can be accessed easily through the XIPropToFloat() function.

Code originally written by Simon Thum.

Signed-off-by: Peter Hutterer <peter.hutterer at redhat.com>
---
 Xi/xiproperty.c              |   43 +++++++++++++++++++++++++++++++++++++++++-
 include/exevents.h           |    5 ++++
 include/xserver-properties.h |    3 ++
 3 files changed, 50 insertions(+), 1 deletions(-)

diff --git a/Xi/xiproperty.c b/Xi/xiproperty.c
index 5f435ff..cdfa25f 100644
--- a/Xi/xiproperty.c
+++ b/Xi/xiproperty.c
@@ -49,7 +49,8 @@ static struct dev_properties
     Atom type;
     char *name;
 } dev_properties[] = {
-    {0, XI_PROP_ENABLED}
+    {0, XI_PROP_ENABLED},
+    {0, XATOM_FLOAT}
 };
 
 static long XIPropHandlerID = 1;
@@ -126,6 +127,46 @@ XIPropToInt(XIPropertyValuePtr val, int **buf_return)
     return Success;
 }
 
+/**
+ * Convert the given property's value(s) into floats and store them in @buf.
+ * If @buf is NULL, memory is allocated automatically and must be freed by the
+ * caller.
+ *
+ * Possible errors returned:
+ * Success
+ * BadMatch ... Wrong atom type, atom is not XA_INTEGER
+ * BadValue ... Wrong format, format is not 32
+ * BadAlloc ... NULL passed as buffer and allocation failed.
+ *
+ * @return Success or the error code if an error occured.
+ */
+_X_EXPORT int
+XIPropToFloat(XIPropertyValuePtr val, float **buf_return)
+{
+    int i;
+    float *buf;
+
+    if (!val->type || val->type != XIGetKnownProperty(XATOM_FLOAT))
+        return BadMatch;
+
+    if (val->format != 32)
+        return BadValue;
+
+    buf = *buf_return;
+    if (!buf)
+    {
+        buf = xcalloc(val->size, sizeof(float));
+        if (!buf)
+            return BadAlloc;
+
+        *buf_return = buf;
+    }
+
+    for (i = 0; i < val->size; i++)
+           buf[i] = (*(float*)val->data);
+
+    return Success;
+}
 
 /**
  * Init those properties that are allocated by the server and most likely used
diff --git a/include/exevents.h b/include/exevents.h
index d5c8c01..936a0d2 100644
--- a/include/exevents.h
+++ b/include/exevents.h
@@ -256,4 +256,9 @@ extern _X_EXPORT int XIPropToInt(
         int **buf_return
 );
 
+extern _X_EXPORT int XIPropToFloat(
+        XIPropertyValuePtr val,
+        float **buf_return
+);
+
 #endif /* EXEVENTS_H */
diff --git a/include/xserver-properties.h b/include/xserver-properties.h
index 4d602b5..0a0e849 100644
--- a/include/xserver-properties.h
+++ b/include/xserver-properties.h
@@ -26,6 +26,9 @@
 #ifndef _XSERVER_PROPERTIES_H_
 #define _XSERVER_PROPERTIES_H_
 
+/* Type for a 4 byte float number */
+#define XATOM_FLOAT "FLOAT"
+
 /* BOOL. 0 - device disabled, 1 - device enabled */
 #define XI_PROP_ENABLED      "Device Enabled"
 
-- 
1.6.0.4