1 /*
2 * COPYRIGHT: See COPYING in the top level directory
3 * PROJECT: ReactOS DNS Shared Library
4 * FILE: lib/dnslib/flatbuf.c
5 * PURPOSE: Functions for managing the Flat Buffer Implementation (FLATBUF)
6 */
7
8 /* INCLUDES ******************************************************************/
9 #include "precomp.h"
10
11 /* DATA **********************************************************************/
12
13 /* FUNCTIONS *****************************************************************/
14
15 VOID
16 WINAPI
FlatBuf_Init(IN PFLATBUFF FlatBuffer,IN PVOID Buffer,IN SIZE_T Size)17 FlatBuf_Init(IN PFLATBUFF FlatBuffer,
18 IN PVOID Buffer,
19 IN SIZE_T Size)
20 {
21 /* Set up the Flat Buffer start, current and ending position */
22 FlatBuffer->Buffer = Buffer;
23 FlatBuffer->BufferPos = (ULONG_PTR)Buffer;
24 FlatBuffer->BufferEnd = (PVOID)(FlatBuffer->BufferPos + Size);
25
26 /* Setup the current size and the available size */
27 FlatBuffer->BufferSize = FlatBuffer->BufferFreeSize = Size;
28 }
29
30 PVOID
31 WINAPI
FlatBuf_Arg_Reserve(IN OUT PULONG_PTR Position,IN OUT PSIZE_T FreeSize,IN SIZE_T Size,IN ULONG Align)32 FlatBuf_Arg_Reserve(IN OUT PULONG_PTR Position,
33 IN OUT PSIZE_T FreeSize,
34 IN SIZE_T Size,
35 IN ULONG Align)
36 {
37 ULONG_PTR NewPosition, OldPosition = *Position;
38 SIZE_T NewFreeSize = *FreeSize;
39
40 /* Start by aligning our position */
41 if (Align) OldPosition += (Align - 1) & ~Align;
42
43 /* Update it */
44 NewPosition = OldPosition + Size;
45
46 /* Update Free Size */
47 NewFreeSize += (OldPosition - NewPosition);
48
49 /* Save new values */
50 *Position = NewPosition;
51 *FreeSize = NewFreeSize;
52
53 /* Check if we're out of space or not */
54 if (NewFreeSize > 0) return (PVOID)OldPosition;
55 return NULL;
56 }
57
58 PVOID
59 WINAPI
FlatBuf_Arg_CopyMemory(IN OUT PULONG_PTR Position,IN OUT PSIZE_T FreeSize,IN PVOID Buffer,IN SIZE_T Size,IN ULONG Align)60 FlatBuf_Arg_CopyMemory(IN OUT PULONG_PTR Position,
61 IN OUT PSIZE_T FreeSize,
62 IN PVOID Buffer,
63 IN SIZE_T Size,
64 IN ULONG Align)
65 {
66 PVOID Destination;
67
68 /* First reserve the memory */
69 Destination = FlatBuf_Arg_Reserve(Position, FreeSize, Size, Align);
70 if (Destination)
71 {
72 /* We have space, do the copy */
73 RtlCopyMemory(Destination, Buffer, Size);
74 }
75
76 /* Return the pointer to the data */
77 return Destination;
78 }
79
80 PVOID
81 WINAPI
FlatBuf_Arg_WriteString(IN OUT PULONG_PTR Position,IN OUT PSIZE_T FreeSize,IN PVOID String,IN BOOLEAN IsUnicode)82 FlatBuf_Arg_WriteString(IN OUT PULONG_PTR Position,
83 IN OUT PSIZE_T FreeSize,
84 IN PVOID String,
85 IN BOOLEAN IsUnicode)
86 {
87 PVOID Destination;
88 SIZE_T StringLength;
89 ULONG Align;
90
91 /* Calculate the string length */
92 if (IsUnicode)
93 {
94 /* Get the length in bytes and use WCHAR alignment */
95 StringLength = (wcslen((LPWSTR)String) + 1) * sizeof(WCHAR);
96 Align = sizeof(WCHAR);
97 }
98 else
99 {
100 /* Get the length in bytes and use CHAR alignment */
101 StringLength = strlen((LPSTR)String) + 1;
102 Align = sizeof(CHAR);
103 }
104
105 /* Now reserve the memory */
106 Destination = FlatBuf_Arg_Reserve(Position, FreeSize, StringLength, Align);
107 if (Destination)
108 {
109 /* We have space, do the copy */
110 RtlCopyMemory(Destination, String, StringLength);
111 }
112
113 /* Return the pointer to the data */
114 return Destination;
115 }
116
117