mirror of
https://github.com/reactos/reactos.git
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116 lines
3.1 KiB
C
116 lines
3.1 KiB
C
/*
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* COPYRIGHT: See COPYING in the top level directory
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* PROJECT: ReactOS DNS Shared Library
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* FILE: lib/dnslib/flatbuf.c
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* PURPOSE: Functions for managing the Flat Buffer Implementation (FLATBUF)
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*/
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/* INCLUDES ******************************************************************/
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#include "precomp.h"
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/* DATA **********************************************************************/
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/* FUNCTIONS *****************************************************************/
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VOID
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WINAPI
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FlatBuf_Init(IN PFLATBUFF FlatBuffer,
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IN PVOID Buffer,
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IN SIZE_T Size)
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{
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/* Set up the Flat Buffer start, current and ending position */
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FlatBuffer->Buffer = Buffer;
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FlatBuffer->BufferPos = (ULONG_PTR)Buffer;
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FlatBuffer->BufferEnd = (PVOID)(FlatBuffer->BufferPos + Size);
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/* Setup the current size and the available size */
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FlatBuffer->BufferSize = FlatBuffer->BufferFreeSize = Size;
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}
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PVOID
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WINAPI
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FlatBuf_Arg_Reserve(IN OUT PULONG_PTR Position,
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IN OUT PSIZE_T FreeSize,
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IN SIZE_T Size,
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IN ULONG Align)
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{
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ULONG_PTR NewPosition, OldPosition = *Position;
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SIZE_T NewFreeSize = *FreeSize;
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/* Start by aligning our position */
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if (Align) OldPosition += (Align - 1) & ~Align;
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/* Update it */
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NewPosition = OldPosition + Size;
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/* Update Free Size */
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NewFreeSize += (OldPosition - NewPosition);
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/* Save new values */
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*Position = NewPosition;
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*FreeSize = NewFreeSize;
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/* Check if we're out of space or not */
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if (NewFreeSize > 0) return (PVOID)OldPosition;
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return NULL;
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}
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PVOID
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WINAPI
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FlatBuf_Arg_CopyMemory(IN OUT PULONG_PTR Position,
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IN OUT PSIZE_T FreeSize,
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IN PVOID Buffer,
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IN SIZE_T Size,
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IN ULONG Align)
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{
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PVOID Destination;
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/* First reserve the memory */
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Destination = FlatBuf_Arg_Reserve(Position, FreeSize, Size, Align);
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if (Destination)
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{
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/* We have space, do the copy */
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RtlCopyMemory(Destination, Buffer, Size);
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}
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/* Return the pointer to the data */
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return Destination;
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}
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PVOID
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WINAPI
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FlatBuf_Arg_WriteString(IN OUT PULONG_PTR Position,
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IN OUT PSIZE_T FreeSize,
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IN PVOID String,
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IN BOOLEAN IsUnicode)
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{
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PVOID Destination;
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SIZE_T StringLength;
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ULONG Align;
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/* Calculate the string length */
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if (IsUnicode)
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{
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/* Get the length in bytes and use WCHAR alignment */
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StringLength = (wcslen((LPWSTR)String) + 1) * sizeof(WCHAR);
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Align = sizeof(WCHAR);
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}
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else
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{
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/* Get the length in bytes and use CHAR alignment */
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StringLength = strlen((LPSTR)String) + 1;
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Align = sizeof(CHAR);
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}
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/* Now reserve the memory */
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Destination = FlatBuf_Arg_Reserve(Position, FreeSize, StringLength, Align);
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if (Destination)
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{
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/* We have space, do the copy */
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RtlCopyMemory(Destination, String, StringLength);
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}
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/* Return the pointer to the data */
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return Destination;
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}
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