51 lines
1.2 KiB
C++
51 lines
1.2 KiB
C++
#include "stdinc.h"
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#include "debmacro.h"
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#include "util.h"
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#include "fusiontrace.h"
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BOOL
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FusionpHashUnicodeString(
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PCWSTR String,
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SIZE_T cch,
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PULONG HashValue,
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bool fCaseInsensitive
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)
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{
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BOOL fSuccess = FALSE;
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FN_TRACE_WIN32(fSuccess);
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ULONG TmpHashValue = 0;
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if (HashValue != NULL)
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*HashValue = 0;
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PARAMETER_CHECK(HashValue != NULL);
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//
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// Note that if you change this implementation, you have to have the implementation inside
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// ntdll change to match it. Since that's hard and will affect everyone else in the world,
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// DON'T CHANGE THIS ALGORITHM NO MATTER HOW GOOD OF AN IDEA IT SEEMS TO BE! This isn't the
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// most perfect hashing algorithm, but its stability is critical to being able to match
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// previously persisted hash values.
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//
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if (fCaseInsensitive)
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{
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while (cch-- != 0)
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{
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WCHAR Char = *String++;
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TmpHashValue = (TmpHashValue * 65599) + ::FusionpRtlUpcaseUnicodeChar(Char);
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}
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}
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else
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{
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while (cch-- != 0)
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TmpHashValue = (TmpHashValue * 65599) + *String++;
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}
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*HashValue = TmpHashValue;
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fSuccess = TRUE;
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Exit:
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return fSuccess;
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}
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