xref: /reactos/drivers/filters/fltmgr/Lib.c (revision 8a978a17)
1 /*
2 * PROJECT:         Filesystem Filter Manager
3 * LICENSE:         GPL - See COPYING in the top level directory
4 * FILE:            drivers/filters/fltmgr/Lib.c
5 * PURPOSE:         Miscellaneous library functions
6 * PROGRAMMERS:     Ged Murphy (gedmurphy@reactos.org)
7 */
8 
9 /* INCLUDES ******************************************************************/
10 
11 #include "fltmgr.h"
12 
13 #define NDEBUG
14 #include <debug.h>
15 
16 
17 /* DATA *********************************************************************/
18 
19 
20 
21 /* FUNCTIONS **********************************************/
22 
23 VOID
24 FltpFreeUnicodeString(_In_ PUNICODE_STRING String)
25 {
26     /* Free up any existing buffer */
27     if (String->Buffer)
28     {
29         ExFreePoolWithTag(String->Buffer, FM_TAG_UNICODE_STRING);
30     }
31 
32     /* Empty the string */
33     String->Buffer = NULL;
34     String->Length = 0;
35     String->MaximumLength = 0;
36 }
37 
38 NTSTATUS
39 FltpReallocateUnicodeString(_In_ PUNICODE_STRING String,
40                             _In_ SIZE_T NewLength,
41                             _In_ BOOLEAN CopyExisting)
42 {
43     PWCH NewBuffer;
44 
45     /* Don't bother reallocating if the buffer is smaller */
46     if (NewLength <= String->MaximumLength)
47     {
48         String->Length = 0;
49         return STATUS_SUCCESS;
50     }
51 
52     /* Allocate a new buffer at the size requested */
53     NewBuffer = ExAllocatePoolWithTag(PagedPool, NewLength, FM_TAG_UNICODE_STRING);
54     if (NewBuffer == NULL) return STATUS_INSUFFICIENT_RESOURCES;
55 
56     if (CopyExisting)
57     {
58         /* Copy the old data across */
59         RtlCopyMemory(NewBuffer, String->Buffer, String->Length);
60     }
61     else
62     {
63         /* Reset the length */
64         String->Length = 0;
65     }
66 
67     /* Free any old buffer */
68     if (String->Buffer)
69         ExFreePoolWithTag(String->Buffer, FM_TAG_UNICODE_STRING);
70 
71     /* Update the lengths */
72     String->Buffer = NewBuffer;
73     String->MaximumLength = NewLength;
74 
75     return STATUS_SUCCESS;
76 }
77 
78 NTSTATUS
79 FltpCopyUnicodeString(_In_ PUNICODE_STRING StringOne,
80                       _In_ PUNICODE_STRING StringTwo)
81 {
82     return 0;
83 }
84