windows-nt/Source/XPSP1/NT/published/sdk/inc/stralign.h

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2020-09-26 03:20:57 -05:00
/*++
Copyright (c) 2000 Microsoft Corporation
Module Name:
stralign.h
Abstract:
This module contains macros and prototypes to expose the unaligned wide
character interfaces.
Public interfaces created or declared here include:
ua_CharUpper()
ua_CharUpperW()
ua_lstrcmp()
ua_lstrcmpW()
ua_lstrcmpi()
ua_lstrcmpiW()
ua_lstrlen()
ua_lstrlenW()
ua_tcscpy()
ua_wcschr()
ua_wcscpy()
ua_wcslen()
ua_wcsrchr()
STRUC_ALIGNED_STACK_COPY()
TSTR_ALIGNED()
TSTR_ALIGNED_STACK_COPY()
WSTR_ALIGNED()
WSTR_ALIGNED_STACK_COPY()
Author:
Revision History:
--*/
#if !defined(__STRALIGN_H_) && !defined(MIDL_PASS)
#define __STRALIGN_H_
#ifdef __cplusplus
extern "C" {
#endif
#if defined(_X86_)
//
// Alignment of unicode strings is not necessary on X86.
//
#define WSTR_ALIGNED(s) TRUE
#define ua_CharUpperW CharUpperW
#define ua_lstrcmpiW lstrcmpiW
#define ua_lstrcmpW lstrcmpW
#define ua_lstrlenW lstrlenW
#define ua_wcschr wcschr
#define ua_wcscpy wcscpy
#define ua_wcslen wcslen
#define ua_wcsrchr wcsrchr
#else
//
// The C runtime libraries expect aligned string pointers. Following are the
// prototypes for our own, slower worker functions that accept unaligned
// UNICODE strings.
//
//
// Macro to determine whether a pointer to a unicode character is naturally
// aligned.
//
#define WSTR_ALIGNED(s) (((DWORD_PTR)(s) & (sizeof(WCHAR)-1)) == 0)
//
// Platform-specific prototypes for worker functions exported from kernel32.
// Do not call these directly, they do not exist on all platforms. Instead
// use the equivalent ua_xxx() routines.
//
LPUWSTR
WINAPI
uaw_CharUpperW(
IN OUT LPUWSTR String
);
int
APIENTRY
uaw_lstrcmpW(
IN PCUWSTR String1,
IN PCUWSTR String2
);
int
APIENTRY
uaw_lstrcmpiW(
IN PCUWSTR String1,
IN PCUWSTR String2
);
int
WINAPI
uaw_lstrlenW(
IN LPCUWSTR String
);
PUWSTR
__cdecl
uaw_wcschr(
IN PCUWSTR String,
IN WCHAR Character
);
PUWSTR
_cdecl
uaw_wcscpy(
IN PUWSTR Destination,
IN PCUWSTR Source
);
size_t
__cdecl
uaw_wcslen(
IN PCUWSTR String
);
PUWSTR
__cdecl
uaw_wcsrchr(
IN PCUWSTR String,
IN WCHAR Character
);
//
// Following are the inline wrappers that determine the optimal worker function
// to call based on the alignment of the UNICODE string arguments. Their
// behavior is otherwise identical to the corresponding standard run-time
// routiunes.
//
#if defined(CharUpper)
__inline
LPUWSTR
static
ua_CharUpperW(
LPUWSTR String
)
{
if (WSTR_ALIGNED(String)) {
return CharUpperW( (PWSTR)String );
} else {
return uaw_CharUpperW( String );
}
}
#endif
#if defined(lstrcmp)
__inline
int
static
ua_lstrcmpW(
IN LPCUWSTR String1,
IN LPCUWSTR String2
)
{
if (WSTR_ALIGNED(String1) && WSTR_ALIGNED(String2)) {
return lstrcmpW( (LPCWSTR)String1, (LPCWSTR)String2);
} else {
return uaw_lstrcmpW( String1, String2 );
}
}
#endif
#if defined(lstrcmpi)
__inline
int
static
ua_lstrcmpiW(
IN LPCUWSTR String1,
IN LPCUWSTR String2
)
{
if (WSTR_ALIGNED(String1) && WSTR_ALIGNED(String2)) {
return lstrcmpiW( (LPCWSTR)String1, (LPCWSTR)String2 );
} else {
return uaw_lstrcmpiW( String1, String2 );
}
}
#endif
#if defined(lstrlen)
__inline
int
static
ua_lstrlenW(
IN LPCUWSTR String
)
{
if (WSTR_ALIGNED(String)) {
return lstrlenW( (PCWSTR)String );
} else {
return uaw_lstrlenW( String );
}
}
#endif
#if defined(_WSTRING_DEFINED)
//
// Certain run-time string functions are overloaded in C++, to avoid
// inadvertent stripping of the const attribute.
//
// The functions of interest here include: wcschr and wcsrchr.
//
// There are three flavors of these functions:
//
// Flavor Returns Parameter
//
// 1 PWSTR PCWSTR
// 2 PCWSTR PCWSTR
// 3 PWSTR PWSTR
//
// string.h declares flavor 1 whether for C or C++. This is the non-ANSI,
// backward compatible mode.
//
// wchar.h declares flavor 1 if C, or flavors 2 and 3 if C++. This is the
// ANSI method.
//
// Our corresponding functions need to match what was declared. The way
// we can tell is by looking at _WConst_return... if it is defined then
// we want to match the prototypes in wchar.h, otherwise we'll match
// the prototypes in string.h.
//
#if defined(_WConst_return)
typedef _WConst_return WCHAR UNALIGNED *PUWSTR_C;
#else
typedef WCHAR UNALIGNED *PUWSTR_C;
#endif
//
// Here is flavor 1 or 2
//
__inline
PUWSTR_C
static
ua_wcschr(
IN PCUWSTR String,
IN WCHAR Character
)
{
if (WSTR_ALIGNED(String)) {
return wcschr((PCWSTR)String, Character);
} else {
return (PUWSTR_C)uaw_wcschr(String, Character);
}
}
__inline
PUWSTR_C
static
ua_wcsrchr(
IN PCUWSTR String,
IN WCHAR Character
)
{
if (WSTR_ALIGNED(String)) {
return wcsrchr((PCWSTR)String, Character);
} else {
return (PUWSTR_C)uaw_wcsrchr(String, Character);
}
}
#if defined(__cplusplus) && defined(_WConst_Return)
//
// Here is flavor 3
//
__inline
PUWSTR
static
ua_wcschr(
IN PUWSTR String,
IN WCHAR Character
)
{
if (WSTR_ALIGNED(String)) {
return wcschr(String, Character);
} else {
return uaw_wcschr((PCUWSTR)String, Character);
}
}
__inline
PUWSTR
static
ua_wcsrchr(
IN PUWSTR String,
IN WCHAR Character
)
{
if (WSTR_ALIGNED(String)) {
return wcsrchr(String, Character);
} else {
return uaw_wcsrchr((PCUWSTR)String, Character);
}
}
#endif // __cplusplus && _WConst_Return
__inline
PUWSTR
static
ua_wcscpy(
IN PUWSTR Destination,
IN PCUWSTR Source
)
{
if (WSTR_ALIGNED(Source) && WSTR_ALIGNED(Destination)) {
return wcscpy( (PWSTR)Destination, (PCWSTR)Source );
} else {
return uaw_wcscpy( Destination, Source );
}
}
__inline
size_t
static
ua_wcslen(
IN PCUWSTR String
)
{
if (WSTR_ALIGNED(String)) {
return wcslen( (PCWSTR)String );
} else {
return uaw_wcslen( String );
}
}
#endif // _WSTRING_DEFINED
#endif // _X86_
//++
//
// VOID
// WSTR_ALIGNED_STACK_COPY (
// OUT PCWSTR *TargetString,
// IN PCUWSTR SourceString OPTIONAL
// )
//
// VOID
// TSTR_ALIGNED_STACK_COPY (
// OUT PCTSTR *TargetString,
// IN PCUTSTR SourceString OPTIONAL
// )
//
// Routine Description:
//
// These macros set TargetString to an aligned pointer to the string
// represented by SourceString. If necessary, an aligned copy of
// SourceString is copied onto the stack.
//
// Arguments:
//
// TargetString - Supplies a pointer to a pointer to the resultant
// string. This may be the same as SourceString if
// that argument is aligned.
//
// SourceString - Supplies a pointer to the possibly unaligned UNICODE
// string.
//
// Return Value:
//
// None.
//
// Note:
//
// These macros may allocate memory on the stack via the CRT function
// _alloca(). This memory is "freed" when the calling function exits.
// As a result, do not use these macros inside of a loop that may execute
// a large number of times - instead, use a wrapper function, or use
// an explicit buffer like this:
//
// TCHAR AlignedStringBuffer[ MAX_FOOSTR_CHARS ];
// PTSTR AlignedString;
//
// while (a < b) {
// ...
// if (TSTR_ALIGNED(s) {
// AlignedString = s;
// } else {
// AlignedString = (PTSTR)ua_tcscpy(AlignedStringBuffer,s);
// }
// SomeSystemFunction(AlignedString);
// ...
// }
//
//
//--
//
// __UA_WSTRSIZE returns the number of bytes required to store the
// supplied null-terminated UNICODE string.
//
// __UA_LOCALCOPY accepts a pointer to unaligned data and a size. It
// allocates an aligned buffer on the stack and copies the data into
// it, returning a pointer to the buffer.
//
#if !defined(__UA_WCSLEN)
#define __UA_WCSLEN ua_wcslen
#endif
#define __UA_WSTRSIZE(s) ((__UA_WCSLEN(s)+1)*sizeof(WCHAR))
#define __UA_STACKCOPY(p,s) memcpy(_alloca(s),p,s)
//
// Note that NULL is aligned.
//
#if defined(_X86_)
#define WSTR_ALIGNED_STACK_COPY(d,s) (*(d) = (PCWSTR)(s))
#else
//
// Use of an inline function here is not possible, as the results of
// the _alloca() will not be preserved upon return from the function.
//
#define WSTR_ALIGNED_STACK_COPY(d,s) \
{ \
PCUWSTR __ua_src; \
ULONG __ua_size; \
PWSTR __ua_dst; \
\
__ua_src = (s); \
if (WSTR_ALIGNED(__ua_src)) { \
__ua_dst = (PWSTR)__ua_src; \
} else { \
__ua_size = __UA_WSTRSIZE(__ua_src); \
__ua_dst = (PWSTR)_alloca(__ua_size); \
memcpy(__ua_dst,__ua_src,__ua_size); \
} \
*(d) = (PCWSTR)__ua_dst; \
}
#endif
#define ASTR_ALIGNED_STACK_COPY(d,s) (*(d) = (PCSTR)(s))
//++
//
// <type> CONST *
// STRUC_ALIGNED_STACK_COPY (
// IN <type name>,
// IN PVOID Struc OPTIONAL
// )
//
// Routine Description:
//
// This macro returns an aligned pointer to Struc, creating a local
// copy on the stack if necessary.
//
// This should be used only for relatively small structures, and efforts
// should be made to align the structure properly in the first place. Use
// this macro only as a last resort.
//
// Arguments:
//
// <type> - The type specifier of Struc
//
// Struc - Supplies a pointer to the structure in question.
//
// Return Value:
//
// Returns a const pointer to Struc if it is properly aligned, or a pointer
// to a stack-allocated copy of Struc if it is not.
//
//--
#if !defined(_X86_)
#define __UA_STRUC_ALIGNED(t,s) \
(((DWORD_PTR)(s) & (TYPE_ALIGNMENT(t)-1)) == 0)
#define STRUC_ALIGNED_STACK_COPY(t,s) \
__UA_STRUC_ALIGNED(t,s) ? \
((t const *)(s)) : \
((t const *)__UA_STACKCOPY((s),sizeof(t)))
#else
#define STRUC_ALIGNED_STACK_COPY(t,s) ((CONST t *)(s))
#endif
#if defined(UNICODE)
#define TSTR_ALIGNED_STACK_COPY(d,s) WSTR_ALIGNED_STACK_COPY(d,s)
#define TSTR_ALIGNED(x) WSTR_ALIGNED(x)
#define ua_CharUpper ua_CharUpperW
#define ua_lstrcmp ua_lstrcmpW
#define ua_lstrcmpi ua_lstrcmpiW
#define ua_lstrlen ua_lstrlenW
#define ua_tcscpy ua_wcscpy
#else
#define TSTR_ALIGNED_STACK_COPY(d,s) ASTR_ALIGNED_STACK_COPY(d,s)
#define TSTR_ALIGNED(x) TRUE
#define ua_CharUpper CharUpperA
#define ua_lstrcmp lstrcmpA
#define ua_lstrcmpi lstrcmpiA
#define ua_lstrlen lstrlenA
#define ua_tcscpy strcpy
#endif // UNICODE
#ifdef __cplusplus
}
#endif
#endif // __STRALIGN_H_