setupapi: Avoid unnecessary buffer allocation in SETUPDI_EnumerateMatchingDeviceInstances().

Signed-off-by: Zebediah Figura <z.figura12@gmail.com> Signed-off-by: Alexandre Julliard <julliard@winehq.org>

setupapi: Avoid unnecessary buffer allocation in SETUPDI_EnumerateMatchingDeviceInstances().
0c0aa90a · Zebediah Figura · Alexandre Julliard · 462c74bc · 0c0aa90a
Commit 0c0aa90a authored Nov 27, 2018 by Zebediah Figura Committed by Alexandre Julliard Nov 28, 2018
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Showing with 4 additions and 10 deletions

devinst.c dlls/setupapi/devinst.c +4 -10

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--- a/dlls/setupapi/devinst.c
+++ b/dlls/setupapi/devinst.c
@@ -2083,6 +2083,7 @@ static void SETUPDI_EnumerateMatchingDeviceInstances(struct DeviceInfoSet *set,
        LPCWSTR enumerator, LPCWSTR deviceName, HKEY deviceKey,
        const GUID *class, DWORD flags)
 {
+    WCHAR id[MAX_DEVICE_ID_LEN];
    DWORD i, len;
    WCHAR deviceInstance[MAX_PATH];
    LONG l = ERROR_SUCCESS;
@@ -2120,18 +2121,11 @@ static void SETUPDI_EnumerateMatchingDeviceInstances(struct DeviceInfoSet *set,
                        {
                            static const WCHAR fmt[] =
                             {'%','s','\\','%','s','\\','%','s',0};
-                            LPWSTR instanceId;

-                            instanceId = HeapAlloc(GetProcessHeap(), 0,
-                                (lstrlenW(enumerator) + lstrlenW(deviceName) +
-                                lstrlenW(deviceInstance) + 3) * sizeof(WCHAR));
-                            if (instanceId)
+                            if (snprintfW(id, ARRAY_SIZE(id), fmt, enumerator,
+                                    deviceName, deviceInstance) != -1)
                            {
-                                sprintfW(instanceId, fmt, enumerator,
-                                        deviceName, deviceInstance);
-                                SETUPDI_CreateDeviceInfo(set, &deviceClass,
-                                        instanceId, FALSE);
-                                HeapFree(GetProcessHeap(), 0, instanceId);
+                                SETUPDI_CreateDeviceInfo(set, &deviceClass, id, FALSE);
                            }
                        }
                    }