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123 lines
3.3 KiB
123 lines
3.3 KiB
/*++
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Copyright (c) 1991-92 Microsoft Corporation
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Module Name:
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PrefMax.c
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Abstract:
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This module contains NetpAdjustPreferedMaximum.
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Author:
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John Rogers (JohnRo) 24-Mar-1991
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Environment:
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Portable to any flat, 32-bit environment. (Uses Win32 typedefs.)
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Requires ANSI C extensions: slash-slash comments, long external names.
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Revision History:
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24-Mar-91 JohnRo
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Created.
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03-May-1991 JohnRo
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Added (quiet) debug output. Fixed massive bug (I was using % for
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division - it must have been a long day).
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03-Apr-1992 JohnRo
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Handle preferred maximum of (DWORD)-1.
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Avoid NT-specific header files if we don't need them.
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04-Apr-1992 JohnRo
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Use MAX_PREFERRED_LENGTH equate.
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--*/
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// These must be included first:
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#include <windef.h> // IN, DWORD, etc.
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#include <lmcons.h> // NET_API_STATUS.
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// These may be included in any order:
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#include <debuglib.h> // IF_DEBUG().
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#include <netdebug.h> // FORMAT_DWORD, NetpKdPrint(()).
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#include <netlib.h> // My prototype, NetpSetOptionalArg().
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VOID
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NetpAdjustPreferedMaximum (
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IN DWORD PreferedMaximum,
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IN DWORD EntrySize,
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IN DWORD Overhead,
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OUT LPDWORD BytesToAllocate OPTIONAL,
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OUT LPDWORD EntriesToAllocate OPTIONAL
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)
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/*++
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Routine Description:
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NetpAdjustPreferedMaximum analyzes the prefered maximum length and
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compares it with the size of an entry and the total overhead.
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Arguments:
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PreferedMaximum - the number of bytes "prefered" by the application for
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a given buffer.
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EntrySize - the number of bytes for each entry.
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Overhead - the number of bytes (if any) of overhead. For instance,
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some enum operations have a null at the end of the array returned.
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BytesToAllocate - optionally points to a DWORD which will be set on
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output to the number of bytes to allocate (consistent with the
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prefered maximum, entry size, and overhead).
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EntriesToAllocate - optionally points to a DWORD which will be set with
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the number of entries which BytesToAllocate can contain.
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Return Value:
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None.
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--*/
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{
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if ( (PreferedMaximum <= (EntrySize+Overhead)) ||
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(PreferedMaximum == MAX_PREFERRED_LENGTH) ) {
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NetpSetOptionalArg(BytesToAllocate, EntrySize+Overhead);
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NetpSetOptionalArg(EntriesToAllocate, 1);
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} else {
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DWORD EntryCount;
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EntryCount = (PreferedMaximum-Overhead) / EntrySize;
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NetpSetOptionalArg(
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BytesToAllocate,
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(EntryCount*EntrySize) + Overhead);
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NetpSetOptionalArg(EntriesToAllocate, EntryCount);
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}
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IF_DEBUG(PREFMAX) {
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NetpKdPrint(("NetpAdjustPreferedMaximum: "
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"pref max=" FORMAT_DWORD ", "
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"entry size=" FORMAT_DWORD ", "
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"overhead=" FORMAT_DWORD ".\n",
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PreferedMaximum, EntrySize, Overhead));
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if (BytesToAllocate != NULL) {
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NetpKdPrint(("NetpAdjustPreferedMaximum: bytes to allocate="
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FORMAT_DWORD ".\n", *BytesToAllocate));
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}
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if (EntriesToAllocate != NULL) {
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NetpKdPrint(("NetpAdjustPreferedMaximum: Entries to allocate="
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FORMAT_DWORD ".\n", *EntriesToAllocate));
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}
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}
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}
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