Andrew Eikum : hid: Shift usage values to LSB.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: daa9906cce1add57e1ce8c43f8721c9d7a73ca3d
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=daa9906cce1add57e1ce8c43f8721c9d7a73ca3d

Author: Andrew Eikum <aeikum at codeweavers.com>
Date:   Mon May  6 08:46:42 2019 -0500

hid: Shift usage values to LSB.

Signed-off-by: Andrew Eikum <aeikum at codeweavers.com>
Signed-off-by: Aric Stewart <aric at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 dlls/hid/hidp.c | 33 ++++++++++++++-------------------
 1 file changed, 14 insertions(+), 19 deletions(-)

diff --git a/dlls/hid/hidp.c b/dlls/hid/hidp.c
index 2c4e98a..6a686d4 100644
--- a/dlls/hid/hidp.c
+++ b/dlls/hid/hidp.c
@@ -49,32 +49,27 @@ static NTSTATUS get_report_data(BYTE *report, INT reportLength, INT startBit, IN
         ULONG byte_index = startBit / 8;
         ULONG bit_index = startBit - (byte_index * 8);
         INT mask = (1 << bit_index);
-        *value = (report[byte_index] & mask);
+        *value = !!(report[byte_index] & mask);
     }
     else
     {
+        ULONG remaining_bits = valueSize;
         ULONG byte_index = startBit / 8;
+        ULONG bit_index = startBit % 8;
         ULONG data = 0;
-        ULONG remainingBits = valueSize;
         ULONG shift = 0;
-        ULONG begin_offset = startBit % 8;
-        while (remainingBits)
+        while (remaining_bits)
         {
-            if (remainingBits >= 8)
-            {
-                BYTE mask = 0xff << begin_offset;
-                data |= (report[byte_index] & mask) << shift;
-                byte_index ++;
-                remainingBits -= (8-begin_offset);
-                shift += (8-begin_offset);
-                begin_offset = 0;
-            }
-            else if (remainingBits > 0)
-            {
-                BYTE mask = (0xff >> (8-remainingBits)) << begin_offset;
-                data |= (report[byte_index] & mask) << shift;
-                remainingBits = 0;
-            }
+            ULONG copy_bits = 8 - bit_index;
+            if (remaining_bits < copy_bits)
+                copy_bits = remaining_bits;
+
+            data |= ((report[byte_index] >> bit_index) & ((2 << copy_bits) - 1)) << shift;
+
+            shift += copy_bits;
+            bit_index = 0;
+            byte_index++;
+            remaining_bits -= copy_bits;
         }
         *value = data;
     }