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1046 lines
29 KiB
1046 lines
29 KiB
/*++
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Copyright (c) 1989 Microsoft Corporation
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Module Name:
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Name.c
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NOTE: The code is copied here from FsRtl because it called the pool allocator.
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The function prefixes were changed to avoid confusion.
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Abstract:
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The unicode name support package is for manipulating unicode strings
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The routines allow the caller to dissect and compare strings.
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The following routines are provided by this package:
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o FrsDissectName - This routine takes a path name string and breaks
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into two parts. The first name in the string and the remainder.
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It also checks that the first name is valid for an NT file.
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o FrsColateNames - This routine is used to colate directories
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according to lexical ordering. Lexical ordering is strict unicode
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numerical oerdering.
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o FrsDoesNameContainsWildCards - This routine tells the caller if
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a string contains any wildcard characters.
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o FrsIsNameInExpression - This routine is used to compare a string
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against a template (possibly containing wildcards) to sees if the
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string is in the language denoted by the template.
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Author:
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Gary Kimura [GaryKi] 5-Feb-1990
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Revision History:
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--*/
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#include <ntreppch.h>
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#pragma hdrstop
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#define DEBSUB "NAME:"
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#include <frs.h>
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//
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// Local support routine prototypes
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//
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BOOLEAN
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FrsIsNameInExpressionPrivate (
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IN PUNICODE_STRING Expression,
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IN PUNICODE_STRING Name,
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IN BOOLEAN IgnoreCase,
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IN PWCH UpcaseTable
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);
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VOID
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FrsDissectName (
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IN UNICODE_STRING Path,
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OUT PUNICODE_STRING FirstName,
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OUT PUNICODE_STRING RemainingName
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)
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/*++
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Routine Description:
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This routine cracks a path. It picks off the first element in the
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given path name and provides both it and the remaining part. A path
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is a set of file names separated by backslashes. If a name begins
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with a backslash, the FirstName is the string immediately following
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the backslash. Here are some examples:
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Path FirstName RemainingName
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---- --------- -------------
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empty empty empty
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\ empty empty
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A A empty
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\A A empty
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A\B\C\D\E A B\C\D\E
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*A? *A? empty
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Note that both output strings use the same string buffer memory of the
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input string, and are not necessarily null terminated.
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Also, this routine makes no judgement as to the legality of each
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file name componant. This must be done separatly when each file name
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is extracted.
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Arguments:
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Path - The full path name to crack.
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FirstName - The first name in the path. Don't allocate a buffer for
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this string.
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RemainingName - The rest of the path. Don't allocate a buffer for this
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string.
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Return Value:
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None.
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--*/
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{
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ULONG i = 0;
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ULONG PathLength;
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ULONG FirstNameStart;
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//
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// Make both output strings empty for now
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//
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FRS_ASSERT( ValueIsMultOf2(Path.Length) );
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FirstName->Length = 0;
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FirstName->MaximumLength = 0;
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FirstName->Buffer = NULL;
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RemainingName->Length = 0;
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RemainingName->MaximumLength = 0;
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RemainingName->Buffer = NULL;
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PathLength = Path.Length / sizeof(WCHAR);
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//
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// Check for an empty input string
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//
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if (PathLength == 0) {
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return;
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}
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//
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// Skip over a starting backslash, and make sure there is more.
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//
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if ( Path.Buffer[0] == L'\\' ) {
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i = 1;
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}
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//
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// Now run down the input string until we hit a backslash or the end
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// of the string, remembering where we started;
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//
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for ( FirstNameStart = i;
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(i < PathLength) && (Path.Buffer[i] != L'\\');
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i += 1 ) {
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NOTHING;
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}
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//
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// At this point all characters up to (but not including) i are
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// in the first part. So setup the first name
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//
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FirstName->Length = (USHORT)((i - FirstNameStart) * sizeof(WCHAR));
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FirstName->MaximumLength = FirstName->Length;
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FirstName->Buffer = &Path.Buffer[FirstNameStart];
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//
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// Now the remaining part needs a string only if the first part didn't
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// exhaust the entire input string. We know that if anything is left
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// that is must start with a backslash. Note that if there is only
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// a trailing backslash, the length will get correctly set to zero.
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//
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if (i < PathLength) {
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RemainingName->Length = (USHORT)((PathLength - (i + 1)) * sizeof(WCHAR));
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RemainingName->MaximumLength = RemainingName->Length;
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RemainingName->Buffer = &Path.Buffer[i + 1];
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}
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//
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// And return to our caller
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//
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return;
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}
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BOOLEAN
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FrsDoesNameContainWildCards (
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IN PUNICODE_STRING Name
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)
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/*++
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Routine Description:
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This routine simply scans the input Name string looking for any Nt
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wild card characters.
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Arguments:
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Name - The string to check.
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Return Value:
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BOOLEAN - TRUE if one or more wild card characters was found.
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--*/
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{
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PUSHORT p;
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FRS_ASSERT( ValueIsMultOf2(Name->Length) );
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//
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// Check each character in the name to see if it's a wildcard
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// character.
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//
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if( Name->Length ) {
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for( p = Name->Buffer + (Name->Length / sizeof(WCHAR)) - 1;
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p >= Name->Buffer && *p != L'\\' ;
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p-- ) {
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//
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// check for a wild card character
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//
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if (FrsIsUnicodeCharacterWild( *p )) {
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//
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// Tell caller that this name contains wild cards
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//
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return TRUE;
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}
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}
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}
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//
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// No wildcard characters were found, so return to our caller
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//
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return FALSE;
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}
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BOOLEAN
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FrsAreNamesEqual (
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IN PUNICODE_STRING ConstantNameA,
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IN PUNICODE_STRING ConstantNameB,
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IN BOOLEAN IgnoreCase,
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IN PCWCH UpcaseTable OPTIONAL
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)
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/*++
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Routine Description:
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This routine simple returns whether the two names are exactly equal.
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If the two names are known to be constant, this routine is much
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faster than FrsIsNameInExpression.
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Arguments:
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ConstantNameA - Constant name.
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ConstantNameB - Constant name.
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IgnoreCase - TRUE if the Names should be Upcased before comparing.
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UpcaseTable - If supplied, use this table for case insensitive compares,
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otherwise, use the default system upcase table.
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Return Value:
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BOOLEAN - TRUE if the two names are lexically equal.
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--*/
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{
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ULONG Index;
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ULONG NameLength;
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BOOLEAN FreeStrings = FALSE;
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UNICODE_STRING LocalNameA;
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UNICODE_STRING LocalNameB;
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FRS_ASSERT( ValueIsMultOf2(ConstantNameA->Length) );
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FRS_ASSERT( ValueIsMultOf2(ConstantNameB->Length) );
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//
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// If the names aren't even the same size, then return FALSE right away.
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//
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if ( ConstantNameA->Length != ConstantNameB->Length ) {
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return FALSE;
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}
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NameLength = ConstantNameA->Length / sizeof(WCHAR);
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//
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// If we weren't given an upcase table, we have to upcase the names
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// ourselves.
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//
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if ( IgnoreCase && !ARGUMENT_PRESENT(UpcaseTable) ) {
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NTSTATUS Status;
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Status = RtlUpcaseUnicodeString( &LocalNameA, ConstantNameA, TRUE );
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if ( !NT_SUCCESS(Status) ) {
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XRAISEGENEXCEPTION(FrsErrorInternalError);
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}
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Status = RtlUpcaseUnicodeString( &LocalNameB, ConstantNameB, TRUE );
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if ( !NT_SUCCESS(Status) ) {
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RtlFreeUnicodeString( &LocalNameA );
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XRAISEGENEXCEPTION(FrsErrorInternalError);
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}
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ConstantNameA = &LocalNameA;
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ConstantNameB = &LocalNameB;
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IgnoreCase = FALSE;
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FreeStrings = TRUE;
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}
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//
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// Do either case sensitive or insensitive compare.
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//
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if ( !IgnoreCase ) {
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BOOLEAN BytesEqual;
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BytesEqual = (BOOLEAN) RtlEqualMemory( ConstantNameA->Buffer,
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ConstantNameB->Buffer,
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ConstantNameA->Length );
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if ( FreeStrings ) {
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RtlFreeUnicodeString( &LocalNameA );
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RtlFreeUnicodeString( &LocalNameB );
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}
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return BytesEqual;
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} else {
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for (Index = 0; Index < NameLength; Index += 1) {
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if ( UpcaseTable[ConstantNameA->Buffer[Index]] !=
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UpcaseTable[ConstantNameB->Buffer[Index]] ) {
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return FALSE;
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}
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}
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return TRUE;
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}
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}
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//
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// The following routine is just a wrapper around
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// FrsIsNameInExpressionPrivate to make a last minute fix a bit safer.
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//
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BOOLEAN
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FrsIsNameInExpression (
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IN PUNICODE_STRING Expression,
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IN PUNICODE_STRING Name,
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IN BOOLEAN IgnoreCase,
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IN PWCH UpcaseTable OPTIONAL
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)
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{
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BOOLEAN Result;
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UNICODE_STRING LocalName;
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FRS_ASSERT( ValueIsMultOf2(Expression->Length) );
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FRS_ASSERT( ValueIsMultOf2(Name->Length) );
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//
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// If we weren't given an upcase table, we have to upcase the names
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// ourselves.
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//
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if ( IgnoreCase && !ARGUMENT_PRESENT(UpcaseTable) ) {
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NTSTATUS Status;
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Status = RtlUpcaseUnicodeString( &LocalName, Name, TRUE );
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if ( !NT_SUCCESS(Status) ) {
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XRAISEGENEXCEPTION(FrsErrorInternalError);
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}
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Name = &LocalName;
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IgnoreCase = FALSE;
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} else {
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LocalName.Buffer = NULL;
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}
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//
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// Now call the main routine, remembering to free the upcased string
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// if we allocated one.
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//
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try {
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Result = FrsIsNameInExpressionPrivate( Expression,
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Name,
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IgnoreCase,
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UpcaseTable );
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} finally {
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if (LocalName.Buffer != NULL) {
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RtlFreeUnicodeString( &LocalName );
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}
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}
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return Result;
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}
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#define MATCHES_ARRAY_SIZE 16
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//
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// Local support routine prototypes
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//
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BOOLEAN
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FrsIsNameInExpressionPrivate (
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IN PUNICODE_STRING Expression,
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IN PUNICODE_STRING Name,
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IN BOOLEAN IgnoreCase,
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IN PWCH UpcaseTable
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)
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/*++
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Routine Description:
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This routine compares a Dbcs name and an expression and tells the caller
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if the name is in the language defined by the expression. The input name
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cannot contain wildcards, while the expression may contain wildcards.
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Expression wild cards are evaluated as shown in the nondeterministic
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finite automatons below. Note that ~* and ~? are DOS_STAR and DOS_QM.
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~* is DOS_STAR, ~? is DOS_QM, and ~. is DOS_DOT
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S
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<-----<
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X | | e Y
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X * Y == (0)----->-(1)->-----(2)-----(3)
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S-.
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<-----<
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X | | e Y
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X ~* Y == (0)----->-(1)->-----(2)-----(3)
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X S S Y
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X ?? Y == (0)---(1)---(2)---(3)---(4)
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X . . Y
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X ~.~. Y == (0)---(1)----(2)------(3)---(4)
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| |________|
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| ^ |
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|_______________|
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^EOF or .^
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X S-. S-. Y
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X ~?~? Y == (0)---(1)-----(2)-----(3)---(4)
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| |________|
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| ^ |
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|_______________|
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^EOF or .^
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where S is any single character
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S-. is any single character except the final .
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e is a null character transition
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EOF is the end of the name string
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In words:
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* matches 0 or more characters.
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? matches exactly 1 character.
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DOS_STAR matches 0 or more characters until encountering and matching
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the final . in the name.
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DOS_QM matches any single character, or upon encountering a period or
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end of name string, advances the expression to the end of the
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set of contiguous DOS_QMs.
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DOS_DOT matches either a . or zero characters beyond name string.
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Arguments:
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Expression - Supplies the input expression to check against
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(Caller must already upcase if passing CaseInsensitive TRUE.)
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Name - Supplies the input name to check for.
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IgnoreCase - TRUE if Name should be Upcased before comparing.
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UpcaseTable - UpCase table to use if Ingoring Case.
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Return Value:
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BOOLEAN - TRUE if Name is an element in the set of strings denoted
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by the input Expression and FALSE otherwise.
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--*/
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{
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USHORT NameOffset;
|
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USHORT ExprOffset;
|
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|
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ULONG SrcCount;
|
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ULONG DestCount;
|
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ULONG PreviousDestCount;
|
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ULONG MatchesCount;
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WCHAR NameChar, ExprChar;
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USHORT LocalBuffer[MATCHES_ARRAY_SIZE * 2];
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USHORT *AuxBuffer = NULL;
|
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USHORT *PreviousMatches;
|
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USHORT *CurrentMatches;
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USHORT MaxState;
|
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USHORT CurrentState;
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|
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BOOLEAN NameFinished = FALSE;
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|
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//
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// The idea behind the algorithm is pretty simple. We keep track of
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// all possible locations in the regular expression that are matching
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// the name. If when the name has been exhausted one of the locations
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// in the expression is also just exhausted, the name is in the language
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// defined by the regular expression.
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//
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FRS_ASSERT( Name->Length != 0 );
|
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FRS_ASSERT( ValueIsMultOf2(Name->Length) );
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FRS_ASSERT( Expression->Length != 0 );
|
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FRS_ASSERT( ValueIsMultOf2(Expression->Length) );
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|
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//
|
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// If one string is empty return FALSE. If both are empty return TRUE.
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//
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if ( (Name->Length == 0) || (Expression->Length == 0) ) {
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return (BOOLEAN)(!(Name->Length + Expression->Length));
|
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}
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|
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//
|
|
// Special case by far the most common wild card search of *
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//
|
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|
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if ((Expression->Length == 2) && (Expression->Buffer[0] == L'*')) {
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return TRUE;
|
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}
|
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|
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FRS_ASSERT( FrsDoesNameContainWildCards( Expression ) );
|
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|
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FRS_ASSERT( !IgnoreCase || ARGUMENT_PRESENT(UpcaseTable) );
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|
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//
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// Also special case expressions of the form *X. With this and the prior
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// case we have covered virtually all normal queries.
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//
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if (Expression->Buffer[0] == L'*') {
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UNICODE_STRING LocalExpression;
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LocalExpression = *Expression;
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LocalExpression.Buffer += 1;
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LocalExpression.Length -= 2;
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|
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//
|
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// Only special case an expression with a single *
|
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//
|
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|
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if ( !FrsDoesNameContainWildCards( &LocalExpression ) ) {
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|
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ULONG StartingNameOffset;
|
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|
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if (Name->Length < (USHORT)(Expression->Length - sizeof(WCHAR))) {
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|
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return FALSE;
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}
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|
|
StartingNameOffset = ( Name->Length -
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LocalExpression.Length ) / sizeof(WCHAR);
|
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|
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//
|
|
// Do a simple memory compare if case sensitive, otherwise
|
|
// we have got to check this one character at a time.
|
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//
|
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|
|
if ( !IgnoreCase ) {
|
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|
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return (BOOLEAN) RtlEqualMemory( LocalExpression.Buffer,
|
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Name->Buffer + StartingNameOffset,
|
|
LocalExpression.Length );
|
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|
|
} else {
|
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|
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for ( ExprOffset = 0;
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ExprOffset < (USHORT)(LocalExpression.Length / sizeof(WCHAR));
|
|
ExprOffset += 1 ) {
|
|
|
|
NameChar = Name->Buffer[StartingNameOffset + ExprOffset];
|
|
NameChar = UpcaseTable[NameChar];
|
|
|
|
ExprChar = LocalExpression.Buffer[ExprOffset];
|
|
|
|
FRS_ASSERT( ExprChar == UpcaseTable[ExprChar] );
|
|
|
|
if ( NameChar != ExprChar ) {
|
|
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
}
|
|
}
|
|
|
|
//
|
|
// Walk through the name string, picking off characters. We go one
|
|
// character beyond the end because some wild cards are able to match
|
|
// zero characters beyond the end of the string.
|
|
//
|
|
// With each new name character we determine a new set of states that
|
|
// match the name so far. We use two arrays that we swap back and forth
|
|
// for this purpose. One array lists the possible expression states for
|
|
// all name characters up to but not including the current one, and other
|
|
// array is used to build up the list of states considering the current
|
|
// name character as well. The arrays are then switched and the process
|
|
// repeated.
|
|
//
|
|
// There is not a one-to-one correspondence between state number and
|
|
// offset into the expression. This is evident from the NFAs in the
|
|
// initial comment to this function. State numbering is not continuous.
|
|
// This allows a simple conversion between state number and expression
|
|
// offset. Each character in the expression can represent one or two
|
|
// states. * and DOS_STAR generate two states: ExprOffset*2 and
|
|
// ExprOffset*2 + 1. All other expreesion characters can produce only
|
|
// a single state. Thus ExprOffset = State/2.
|
|
//
|
|
//
|
|
// Here is a short description of the variables involved:
|
|
//
|
|
// NameOffset - The offset of the current name char being processed.
|
|
//
|
|
// ExprOffset - The offset of the current expression char being processed.
|
|
//
|
|
// SrcCount - Prior match being investigated with current name char
|
|
//
|
|
// DestCount - Next location to put a matching assuming current name char
|
|
//
|
|
// NameFinished - Allows one more itteration through the Matches array
|
|
// after the name is exhusted (to come *s for example)
|
|
//
|
|
// PreviousDestCount - This is used to prevent entry duplication, see coment
|
|
//
|
|
// PreviousMatches - Holds the previous set of matches (the Src array)
|
|
//
|
|
// CurrentMatches - Holds the current set of matches (the Dest array)
|
|
//
|
|
// AuxBuffer, LocalBuffer - the storage for the Matches arrays
|
|
//
|
|
|
|
//
|
|
// Set up the initial variables
|
|
//
|
|
|
|
PreviousMatches = &LocalBuffer[0];
|
|
CurrentMatches = &LocalBuffer[MATCHES_ARRAY_SIZE];
|
|
|
|
PreviousMatches[0] = 0;
|
|
MatchesCount = 1;
|
|
|
|
NameOffset = 0;
|
|
|
|
MaxState = (USHORT)(Expression->Length * 2);
|
|
|
|
while ( !NameFinished ) {
|
|
|
|
if ( NameOffset < Name->Length ) {
|
|
|
|
NameChar = Name->Buffer[NameOffset / sizeof(WCHAR)];
|
|
|
|
NameOffset += sizeof(WCHAR);;
|
|
|
|
} else {
|
|
|
|
NameFinished = TRUE;
|
|
|
|
//
|
|
// if we have already exhasted the expression, cool. Don't
|
|
// continue.
|
|
//
|
|
|
|
if ( PreviousMatches[MatchesCount-1] == MaxState ) {
|
|
|
|
break;
|
|
}
|
|
}
|
|
|
|
|
|
//
|
|
// Now, for each of the previous stored expression matches, see what
|
|
// we can do with this name character.
|
|
//
|
|
|
|
SrcCount = 0;
|
|
DestCount = 0;
|
|
PreviousDestCount = 0;
|
|
|
|
while ( SrcCount < MatchesCount ) {
|
|
|
|
USHORT Length;
|
|
|
|
//
|
|
// We have to carry on our expression analysis as far as possible
|
|
// for each character of name, so we loop here until the
|
|
// expression stops matching. A clue here is that expression
|
|
// cases that can match zero or more characters end with a
|
|
// continue, while those that can accept only a single character
|
|
// end with a break.
|
|
//
|
|
|
|
ExprOffset = (USHORT)((PreviousMatches[SrcCount++] + 1) / 2);
|
|
|
|
|
|
Length = 0;
|
|
|
|
while ( TRUE ) {
|
|
|
|
if ( ExprOffset == Expression->Length ) {
|
|
|
|
break;
|
|
}
|
|
|
|
//
|
|
// The first time through the loop we don't want
|
|
// to increment ExprOffset.
|
|
//
|
|
|
|
ExprOffset += Length;
|
|
Length = sizeof(WCHAR);
|
|
|
|
CurrentState = (USHORT)(ExprOffset * 2);
|
|
|
|
if ( ExprOffset == Expression->Length ) {
|
|
|
|
CurrentMatches[DestCount++] = MaxState;
|
|
break;
|
|
}
|
|
|
|
ExprChar = Expression->Buffer[ExprOffset / sizeof(WCHAR)];
|
|
|
|
FRS_ASSERT( !IgnoreCase || !((ExprChar >= L'a') && (ExprChar <= L'z')) );
|
|
|
|
//
|
|
// Before we get started, we have to check for something
|
|
// really gross. We may be about to exhaust the local
|
|
// space for ExpressionMatches[][], so we have to allocate
|
|
// some memory if this is the case. Yuk!
|
|
//
|
|
|
|
if ( (DestCount >= MATCHES_ARRAY_SIZE - 2) &&
|
|
(AuxBuffer == NULL) ) {
|
|
|
|
ULONG ExpressionChars;
|
|
|
|
ExpressionChars = Expression->Length / sizeof(WCHAR);
|
|
AuxBuffer = FrsAlloc((ExpressionChars+1)*sizeof(USHORT)*2*2);
|
|
|
|
//
|
|
// I don't believe we can have a buffer overrun here. Put an assert
|
|
// to catch any such case.
|
|
//
|
|
FRS_ASSERT((ExpressionChars+1)*sizeof(USHORT)*2*2 >= (MATCHES_ARRAY_SIZE * sizeof(USHORT) + (ExpressionChars+1)*2*sizeof(USHORT)));
|
|
CopyMemory(AuxBuffer, CurrentMatches, MATCHES_ARRAY_SIZE * sizeof(USHORT) );
|
|
|
|
CurrentMatches = AuxBuffer;
|
|
|
|
CopyMemory(AuxBuffer + (ExpressionChars+1)*2, PreviousMatches,
|
|
MATCHES_ARRAY_SIZE * sizeof(USHORT) );
|
|
|
|
PreviousMatches = AuxBuffer + (ExpressionChars+1)*2;
|
|
}
|
|
|
|
//
|
|
// * matches any character zero or more times.
|
|
//
|
|
|
|
if (ExprChar == L'*') {
|
|
|
|
CurrentMatches[DestCount++] = CurrentState;
|
|
CurrentMatches[DestCount++] = CurrentState + 3;
|
|
continue;
|
|
}
|
|
|
|
//
|
|
// DOS_STAR matches any character except . zero or more times.
|
|
//
|
|
|
|
if (ExprChar == DOS_STAR) {
|
|
|
|
BOOLEAN ICanEatADot = FALSE;
|
|
|
|
//
|
|
// If we are at a period, determine if we are allowed to
|
|
// consume it, ie. make sure it is not the last one.
|
|
//
|
|
|
|
if ( !NameFinished && (NameChar == '.') ) {
|
|
|
|
USHORT Offset;
|
|
|
|
for ( Offset = NameOffset;
|
|
Offset < Name->Length;
|
|
Offset += Length ) {
|
|
|
|
if (Name->Buffer[Offset / sizeof(WCHAR)] == L'.') {
|
|
|
|
ICanEatADot = TRUE;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (NameFinished || (NameChar != L'.') || ICanEatADot) {
|
|
|
|
CurrentMatches[DestCount++] = CurrentState;
|
|
CurrentMatches[DestCount++] = CurrentState + 3;
|
|
continue;
|
|
|
|
} else {
|
|
|
|
//
|
|
// We are at a period. We can only match zero
|
|
// characters (ie. the epsilon transition).
|
|
//
|
|
|
|
CurrentMatches[DestCount++] = CurrentState + 3;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
//
|
|
// The following expreesion characters all match by consuming
|
|
// a character, thus force the expression, and thus state
|
|
// forward.
|
|
//
|
|
|
|
CurrentState += (USHORT)(sizeof(WCHAR) * 2);
|
|
|
|
//
|
|
// DOS_QM is the most complicated. If the name is finished,
|
|
// we can match zero characters. If this name is a '.', we
|
|
// don't match, but look at the next expression. Otherwise
|
|
// we match a single character.
|
|
//
|
|
|
|
if ( ExprChar == DOS_QM ) {
|
|
|
|
if ( NameFinished || (NameChar == L'.') ) {
|
|
|
|
continue;
|
|
}
|
|
|
|
CurrentMatches[DestCount++] = CurrentState;
|
|
break;
|
|
}
|
|
|
|
//
|
|
// A DOS_DOT can match either a period, or zero characters
|
|
// beyond the end of name.
|
|
//
|
|
|
|
if (ExprChar == DOS_DOT) {
|
|
|
|
if ( NameFinished ) {
|
|
|
|
continue;
|
|
}
|
|
|
|
if (NameChar == L'.') {
|
|
|
|
CurrentMatches[DestCount++] = CurrentState;
|
|
break;
|
|
}
|
|
}
|
|
|
|
//
|
|
// From this point on a name character is required to even
|
|
// continue, let alone make a match.
|
|
//
|
|
|
|
if ( NameFinished ) {
|
|
|
|
break;
|
|
}
|
|
|
|
//
|
|
// If this expression was a '?' we can match it once.
|
|
//
|
|
|
|
if (ExprChar == L'?') {
|
|
|
|
CurrentMatches[DestCount++] = CurrentState;
|
|
break;
|
|
}
|
|
|
|
//
|
|
// Finally, check if the expression char matches the name char
|
|
//
|
|
|
|
if (ExprChar == (WCHAR)(IgnoreCase ?
|
|
UpcaseTable[NameChar] : NameChar)) {
|
|
|
|
CurrentMatches[DestCount++] = CurrentState;
|
|
break;
|
|
}
|
|
|
|
//
|
|
// The expression didn't match so go look at the next
|
|
// previous match.
|
|
//
|
|
|
|
break;
|
|
}
|
|
|
|
|
|
//
|
|
// Prevent duplication in the destination array.
|
|
//
|
|
// Each of the arrays is montonically increasing and non-
|
|
// duplicating, thus we skip over any source element in the src
|
|
// array if we just added the same element to the destination
|
|
// array. This guarentees non-duplication in the dest. array.
|
|
//
|
|
|
|
if ((SrcCount < MatchesCount) &&
|
|
(PreviousDestCount < DestCount) ) {
|
|
|
|
while (PreviousDestCount < DestCount) {
|
|
|
|
while ( PreviousMatches[SrcCount] <
|
|
CurrentMatches[PreviousDestCount] ) {
|
|
|
|
SrcCount += 1;
|
|
}
|
|
|
|
PreviousDestCount += 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
//
|
|
// If we found no matches in the just finished itteration, it's time
|
|
// to bail.
|
|
//
|
|
|
|
if ( DestCount == 0 ) {
|
|
|
|
if (AuxBuffer != NULL) { FrsFree( AuxBuffer ); }
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
//
|
|
// Swap the meaning the two arrays
|
|
//
|
|
|
|
{
|
|
USHORT *Tmp;
|
|
|
|
Tmp = PreviousMatches;
|
|
|
|
PreviousMatches = CurrentMatches;
|
|
|
|
CurrentMatches = Tmp;
|
|
}
|
|
|
|
MatchesCount = DestCount;
|
|
}
|
|
|
|
|
|
CurrentState = PreviousMatches[MatchesCount-1];
|
|
|
|
if (AuxBuffer != NULL) { FrsFree( AuxBuffer ); }
|
|
|
|
|
|
return (BOOLEAN)(CurrentState == MaxState);
|
|
}
|
|
|