blob: 708ceb0362439f9ed0e64decd5f203518460a174 [file] [log] [blame]
// Copyright 2014 The PDFium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
#include "core/fxcrt/widestring.h"
#include <stddef.h>
#include <string.h>
#include <wchar.h>
#include <algorithm>
#include <sstream>
#include "core/fxcrt/check.h"
#include "core/fxcrt/check_op.h"
#include "core/fxcrt/compiler_specific.h"
#include "core/fxcrt/fx_codepage.h"
#include "core/fxcrt/fx_extension.h"
#include "core/fxcrt/fx_memcpy_wrappers.h"
#include "core/fxcrt/fx_safe_types.h"
#include "core/fxcrt/fx_system.h"
#include "core/fxcrt/numerics/safe_math.h"
#include "core/fxcrt/span_util.h"
#include "core/fxcrt/string_pool_template.h"
#include "core/fxcrt/utf16.h"
// Instantiate.
template class fxcrt::StringViewTemplate<wchar_t>;
template class fxcrt::StringPoolTemplate<WideString>;
template struct std::hash<WideString>;
#define FORCE_ANSI 0x10000
#define FORCE_UNICODE 0x20000
#define FORCE_INT64 0x40000
namespace {
#if defined(WCHAR_T_IS_32_BIT)
size_t FuseSurrogates(pdfium::span<wchar_t> s) {
size_t dest_pos = 0;
for (size_t i = 0; i < s.size(); ++i) {
// TODO(crbug.com/pdfium/2031): Always use UTF-16.
if (pdfium::IsHighSurrogate(s[i]) && i + 1 < s.size() &&
pdfium::IsLowSurrogate(s[i + 1])) {
s[dest_pos++] = pdfium::SurrogatePair(s[i], s[i + 1]).ToCodePoint();
++i;
continue;
}
s[dest_pos++] = s[i];
}
return dest_pos;
}
#endif // defined(WCHAR_T_IS_32_BIT)
constexpr wchar_t kWideTrimChars[] = L"\x09\x0a\x0b\x0c\x0d\x20";
std::optional<size_t> GuessSizeForVSWPrintf(const wchar_t* pFormat,
va_list argList) {
size_t nMaxLen = 0;
UNSAFE_TODO({
for (const wchar_t* pStr = pFormat; *pStr != 0; pStr++) {
if (*pStr != '%' || *(pStr = pStr + 1) == '%') {
++nMaxLen;
continue;
}
int iWidth = 0;
for (; *pStr != 0; pStr++) {
if (*pStr == '#') {
nMaxLen += 2;
} else if (*pStr == '*') {
iWidth = va_arg(argList, int);
} else if (*pStr != '-' && *pStr != '+' && *pStr != '0' &&
*pStr != ' ') {
break;
}
}
if (iWidth == 0) {
iWidth = FXSYS_wtoi(pStr);
while (FXSYS_IsDecimalDigit(*pStr))
++pStr;
}
if (iWidth < 0 || iWidth > 128 * 1024) {
return std::nullopt;
}
uint32_t nWidth = static_cast<uint32_t>(iWidth);
int iPrecision = 0;
if (*pStr == '.') {
pStr++;
if (*pStr == '*') {
iPrecision = va_arg(argList, int);
pStr++;
} else {
iPrecision = FXSYS_wtoi(pStr);
while (FXSYS_IsDecimalDigit(*pStr)) {
++pStr;
}
}
}
if (iPrecision < 0 || iPrecision > 128 * 1024) {
return std::nullopt;
}
uint32_t nPrecision = static_cast<uint32_t>(iPrecision);
int nModifier = 0;
if (*pStr == L'I' && *(pStr + 1) == L'6' && *(pStr + 2) == L'4') {
pStr += 3;
nModifier = FORCE_INT64;
} else {
switch (*pStr) {
case 'h':
nModifier = FORCE_ANSI;
pStr++;
break;
case 'l':
nModifier = FORCE_UNICODE;
pStr++;
break;
case 'F':
case 'N':
case 'L':
pStr++;
break;
}
}
size_t nItemLen = 0;
switch (*pStr | nModifier) {
case 'c':
case 'C':
nItemLen = 2;
va_arg(argList, int);
break;
case 'c' | FORCE_ANSI:
case 'C' | FORCE_ANSI:
nItemLen = 2;
va_arg(argList, int);
break;
case 'c' | FORCE_UNICODE:
case 'C' | FORCE_UNICODE:
nItemLen = 2;
va_arg(argList, int);
break;
case 's': {
const wchar_t* pstrNextArg = va_arg(argList, const wchar_t*);
if (pstrNextArg) {
nItemLen = wcslen(pstrNextArg);
if (nItemLen < 1) {
nItemLen = 1;
}
} else {
nItemLen = 6;
}
} break;
case 'S': {
const char* pstrNextArg = va_arg(argList, const char*);
if (pstrNextArg) {
nItemLen = strlen(pstrNextArg);
if (nItemLen < 1) {
nItemLen = 1;
}
} else {
nItemLen = 6;
}
} break;
case 's' | FORCE_ANSI:
case 'S' | FORCE_ANSI: {
const char* pstrNextArg = va_arg(argList, const char*);
if (pstrNextArg) {
nItemLen = strlen(pstrNextArg);
if (nItemLen < 1) {
nItemLen = 1;
}
} else {
nItemLen = 6;
}
} break;
case 's' | FORCE_UNICODE:
case 'S' | FORCE_UNICODE: {
const wchar_t* pstrNextArg = va_arg(argList, wchar_t*);
if (pstrNextArg) {
nItemLen = wcslen(pstrNextArg);
if (nItemLen < 1) {
nItemLen = 1;
}
} else {
nItemLen = 6;
}
} break;
}
if (nItemLen != 0) {
if (nPrecision != 0 && nItemLen > nPrecision) {
nItemLen = nPrecision;
}
if (nItemLen < nWidth) {
nItemLen = nWidth;
}
} else {
switch (*pStr) {
case 'd':
case 'i':
case 'u':
case 'x':
case 'X':
case 'o':
if (nModifier & FORCE_INT64) {
va_arg(argList, int64_t);
} else {
va_arg(argList, int);
}
nItemLen = 32;
if (nItemLen < nWidth + nPrecision) {
nItemLen = nWidth + nPrecision;
}
break;
case 'a':
case 'A':
case 'e':
case 'E':
case 'g':
case 'G':
va_arg(argList, double);
nItemLen = 128;
if (nItemLen < nWidth + nPrecision) {
nItemLen = nWidth + nPrecision;
}
break;
case 'f':
if (nWidth + nPrecision > 100) {
nItemLen = nPrecision + nWidth + 128;
} else {
double f;
char pszTemp[256];
f = va_arg(argList, double);
FXSYS_snprintf(pszTemp, sizeof(pszTemp), "%*.*f", nWidth,
nPrecision + 6, f);
nItemLen = strlen(pszTemp);
}
break;
case 'p':
va_arg(argList, void*);
nItemLen = 32;
if (nItemLen < nWidth + nPrecision) {
nItemLen = nWidth + nPrecision;
}
break;
case 'n':
va_arg(argList, int*);
break;
}
}
nMaxLen += nItemLen;
}
});
nMaxLen += 32; // Fudge factor.
return nMaxLen;
}
// Returns string unless we ran out of space.
std::optional<WideString> TryVSWPrintf(size_t size,
const wchar_t* pFormat,
va_list argList) {
if (!size)
return std::nullopt;
WideString str;
{
// Span's lifetime must end before ReleaseBuffer() below.
pdfium::span<wchar_t> buffer = str.GetBuffer(size);
// SAFETY: In the following two calls, there's always space in the
// WideString for a terminating NUL that's not included in the span.
// For vswprintf(), MSAN won't untaint the buffer on a truncated write's
// -1 return code even though the buffer is written. Probably just as well
// not to trust the vendor's implementation to write anything anyways.
// See https://crbug.com/705912.
UNSAFE_BUFFERS(
FXSYS_memset(buffer.data(), 0, (size + 1) * sizeof(wchar_t)));
int ret = vswprintf(buffer.data(), size + 1, pFormat, argList);
bool bSufficientBuffer = ret >= 0 || buffer[size - 1] == 0;
if (!bSufficientBuffer)
return std::nullopt;
}
str.ReleaseBuffer(str.GetStringLength());
return str;
}
// Appends a Unicode code point to a `WideString` using either UTF-16 or UTF-32,
// depending on the platform's definition of `wchar_t`.
//
// TODO(crbug.com/pdfium/2031): Always use UTF-16.
// TODO(crbug.com/pdfium/2041): Migrate to `WideString`.
void AppendCodePointToWideString(char32_t code_point, WideString& buffer) {
if (code_point > pdfium::kMaximumSupplementaryCodePoint) {
// Invalid code point above U+10FFFF.
return;
}
#if defined(WCHAR_T_IS_16_BIT)
if (code_point < pdfium::kMinimumSupplementaryCodePoint) {
buffer += static_cast<wchar_t>(code_point);
} else {
// Encode as UTF-16 surrogate pair.
pdfium::SurrogatePair surrogate_pair(code_point);
buffer += surrogate_pair.high();
buffer += surrogate_pair.low();
}
#else
buffer += static_cast<wchar_t>(code_point);
#endif // defined(WCHAR_T_IS_16_BIT)
}
WideString UTF8Decode(ByteStringView bsStr) {
WideString buffer;
int remaining = 0;
char32_t code_point = 0;
for (char byte : bsStr) {
uint8_t code_unit = static_cast<uint8_t>(byte);
if (code_unit < 0x80) {
remaining = 0;
AppendCodePointToWideString(code_unit, buffer);
} else if (code_unit < 0xc0) {
if (remaining > 0) {
--remaining;
code_point = (code_point << 6) | (code_unit & 0x3f);
if (remaining == 0) {
AppendCodePointToWideString(code_point, buffer);
}
}
} else if (code_unit < 0xe0) {
remaining = 1;
code_point = code_unit & 0x1f;
} else if (code_unit < 0xf0) {
remaining = 2;
code_point = code_unit & 0x0f;
} else if (code_unit < 0xf8) {
remaining = 3;
code_point = code_unit & 0x07;
} else {
remaining = 0;
}
}
return buffer;
}
} // namespace
namespace fxcrt {
static_assert(sizeof(WideString) <= sizeof(wchar_t*),
"Strings must not require more space than pointers");
// static
WideString WideString::FormatInteger(int i) {
wchar_t wbuf[32];
swprintf(wbuf, std::size(wbuf), L"%d", i);
return WideString(wbuf);
}
// static
WideString WideString::FormatV(const wchar_t* format, va_list argList) {
va_list argListCopy;
va_copy(argListCopy, argList);
auto guess = GuessSizeForVSWPrintf(format, argListCopy);
va_end(argListCopy);
if (!guess.has_value()) {
return WideString();
}
int maxLen = pdfium::checked_cast<int>(guess.value());
while (maxLen < 32 * 1024) {
va_copy(argListCopy, argList);
std::optional<WideString> ret =
TryVSWPrintf(static_cast<size_t>(maxLen), format, argListCopy);
va_end(argListCopy);
if (ret.has_value())
return ret.value();
maxLen *= 2;
}
return WideString();
}
// static
WideString WideString::Format(const wchar_t* pFormat, ...) {
va_list argList;
va_start(argList, pFormat);
WideString ret = FormatV(pFormat, argList);
va_end(argList);
return ret;
}
WideString::WideString(const wchar_t* pStr, size_t nLen) {
if (nLen) {
// SAFETY: caller ensures `pStr` points to al least `nLen` wchar_t.
m_pData = StringData::Create(UNSAFE_BUFFERS(pdfium::make_span(pStr, nLen)));
}
}
WideString::WideString(wchar_t ch) {
m_pData = StringData::Create(1);
m_pData->m_String[0] = ch;
}
WideString::WideString(const wchar_t* ptr)
: WideString(ptr, ptr ? wcslen(ptr) : 0) {}
WideString::WideString(WideStringView stringSrc) {
if (!stringSrc.IsEmpty()) {
m_pData = StringData::Create(stringSrc.span());
}
}
WideString::WideString(WideStringView str1, WideStringView str2) {
FX_SAFE_SIZE_T nSafeLen = str1.GetLength();
nSafeLen += str2.GetLength();
size_t nNewLen = nSafeLen.ValueOrDie();
if (nNewLen == 0)
return;
m_pData = StringData::Create(nNewLen);
m_pData->CopyContents(str1.span());
m_pData->CopyContentsAt(str1.GetLength(), str2.span());
}
WideString::WideString(const std::initializer_list<WideStringView>& list) {
FX_SAFE_SIZE_T nSafeLen = 0;
for (const auto& item : list)
nSafeLen += item.GetLength();
size_t nNewLen = nSafeLen.ValueOrDie();
if (nNewLen == 0)
return;
m_pData = StringData::Create(nNewLen);
size_t nOffset = 0;
for (const auto& item : list) {
m_pData->CopyContentsAt(nOffset, item.span());
nOffset += item.GetLength();
}
}
WideString& WideString::operator=(const wchar_t* str) {
if (!str || !str[0])
clear();
else
AssignCopy(str, wcslen(str));
return *this;
}
WideString& WideString::operator=(WideStringView str) {
if (str.IsEmpty())
clear();
else
AssignCopy(str.unterminated_c_str(), str.GetLength());
return *this;
}
WideString& WideString::operator=(const WideString& that) {
if (m_pData != that.m_pData)
m_pData = that.m_pData;
return *this;
}
WideString& WideString::operator=(WideString&& that) noexcept {
if (m_pData != that.m_pData)
m_pData = std::move(that.m_pData);
return *this;
}
WideString& WideString::operator+=(const wchar_t* str) {
if (str)
Concat(str, wcslen(str));
return *this;
}
WideString& WideString::operator+=(wchar_t ch) {
Concat(&ch, 1);
return *this;
}
WideString& WideString::operator+=(const WideString& str) {
if (str.m_pData)
Concat(str.m_pData->m_String, str.m_pData->m_nDataLength);
return *this;
}
WideString& WideString::operator+=(WideStringView str) {
if (!str.IsEmpty())
Concat(str.unterminated_c_str(), str.GetLength());
return *this;
}
bool WideString::operator==(const wchar_t* ptr) const {
if (!m_pData)
return !ptr || !ptr[0];
if (!ptr)
return m_pData->m_nDataLength == 0;
// SAFTEY: `wsclen()` comparison ensures there are `m_nDataLength` wchars at
// `ptr` before the terminator, and `m_nDataLength` is within `m_String`.
return wcslen(ptr) == m_pData->m_nDataLength &&
UNSAFE_BUFFERS(FXSYS_wmemcmp(ptr, m_pData->m_String,
m_pData->m_nDataLength)) == 0;
}
bool WideString::operator==(WideStringView str) const {
if (!m_pData)
return str.IsEmpty();
// SAFTEY: Comparison ensure there are `m_nDataLength` wchars in `str`
// and `m_nDataLength is within `m_String`.
return m_pData->m_nDataLength == str.GetLength() &&
UNSAFE_BUFFERS(FXSYS_wmemcmp(
m_pData->m_String, str.unterminated_c_str(), str.GetLength())) ==
0;
}
bool WideString::operator==(const WideString& other) const {
if (m_pData == other.m_pData)
return true;
if (IsEmpty())
return other.IsEmpty();
if (other.IsEmpty())
return false;
return other.m_pData->m_nDataLength == m_pData->m_nDataLength &&
wmemcmp(other.m_pData->m_String, m_pData->m_String,
m_pData->m_nDataLength) == 0;
}
bool WideString::operator<(const wchar_t* ptr) const {
return Compare(ptr) < 0;
}
bool WideString::operator<(WideStringView str) const {
if (!m_pData && !str.unterminated_c_str())
return false;
if (c_str() == str.unterminated_c_str())
return false;
size_t len = GetLength();
size_t other_len = str.GetLength();
// SAFETY: Comparison limited to minimum valid length of either argument.
int result = UNSAFE_BUFFERS(FXSYS_wmemcmp(c_str(), str.unterminated_c_str(),
std::min(len, other_len)));
return result < 0 || (result == 0 && len < other_len);
}
bool WideString::operator<(const WideString& other) const {
return Compare(other) < 0;
}
intptr_t WideString::ReferenceCountForTesting() const {
return m_pData ? m_pData->m_nRefs : 0;
}
ByteString WideString::ToASCII() const {
ByteString result;
result.Reserve(GetLength());
for (wchar_t wc : *this)
result.InsertAtBack(static_cast<char>(wc & 0x7f));
return result;
}
ByteString WideString::ToLatin1() const {
ByteString result;
result.Reserve(GetLength());
for (wchar_t wc : *this)
result.InsertAtBack(static_cast<char>(wc & 0xff));
return result;
}
ByteString WideString::ToDefANSI() const {
size_t dest_len =
FX_WideCharToMultiByte(FX_CodePage::kDefANSI, AsStringView(), {});
if (!dest_len)
return ByteString();
ByteString bstr;
{
// Span's lifetime must end before ReleaseBuffer() below.
pdfium::span<char> dest_buf = bstr.GetBuffer(dest_len);
FX_WideCharToMultiByte(FX_CodePage::kDefANSI, AsStringView(), dest_buf);
}
bstr.ReleaseBuffer(dest_len);
return bstr;
}
ByteString WideString::ToUTF8() const {
return FX_UTF8Encode(AsStringView());
}
ByteString WideString::ToUTF16LE() const {
std::u16string utf16 = FX_UTF16Encode(AsStringView());
ByteString result;
size_t output_length = 0;
{
// Span's lifetime must end before ReleaseBuffer() below.
// 2 bytes required per UTF-16 code unit.
pdfium::span<uint8_t> buffer =
pdfium::as_writable_bytes(result.GetBuffer(utf16.size() * 2 + 2));
for (char16_t c : utf16) {
buffer[output_length++] = c & 0xff;
buffer[output_length++] = c >> 8;
}
buffer[output_length++] = 0;
buffer[output_length++] = 0;
}
result.ReleaseBuffer(output_length);
return result;
}
ByteString WideString::ToUCS2LE() const {
ByteString result;
size_t output_length = 0;
{
// Span's lifetime must end before ReleaseBuffer() below.
// 2 bytes required per UTF-16 code unit.
pdfium::span<uint8_t> buffer =
pdfium::as_writable_bytes(result.GetBuffer(GetLength() * 2 + 2));
for (wchar_t wc : AsStringView()) {
#if defined(WCHAR_T_IS_32_BIT)
if (pdfium::IsSupplementary(wc)) {
continue;
}
#endif
buffer[output_length++] = wc & 0xff;
buffer[output_length++] = wc >> 8;
}
buffer[output_length++] = 0;
buffer[output_length++] = 0;
}
result.ReleaseBuffer(output_length);
return result;
}
WideString WideString::EncodeEntities() const {
WideString ret = *this;
ret.Replace(L"&", L"&amp;");
ret.Replace(L"<", L"&lt;");
ret.Replace(L">", L"&gt;");
ret.Replace(L"\'", L"&apos;");
ret.Replace(L"\"", L"&quot;");
return ret;
}
WideString WideString::Substr(size_t offset) const {
// Unsigned underflow is well-defined and out-of-range is handled by Substr().
return Substr(offset, GetLength() - offset);
}
WideString WideString::Substr(size_t first, size_t count) const {
if (!m_pData) {
return WideString();
}
if (first == 0 && count == GetLength()) {
return *this;
}
return WideString(AsStringView().Substr(first, count));
}
WideString WideString::First(size_t count) const {
return Substr(0, count);
}
WideString WideString::Last(size_t count) const {
// Unsigned underflow is well-defined and out-of-range is handled by Substr().
return Substr(GetLength() - count, count);
}
void WideString::MakeLower() {
if (IsEmpty())
return;
ReallocBeforeWrite(m_pData->m_nDataLength);
FXSYS_wcslwr(m_pData->m_String);
}
void WideString::MakeUpper() {
if (IsEmpty())
return;
ReallocBeforeWrite(m_pData->m_nDataLength);
FXSYS_wcsupr(m_pData->m_String);
}
// static
WideString WideString::FromASCII(ByteStringView bstr) {
WideString result;
result.Reserve(bstr.GetLength());
for (char c : bstr)
result.InsertAtBack(static_cast<wchar_t>(c & 0x7f));
return result;
}
// static
WideString WideString::FromLatin1(ByteStringView bstr) {
WideString result;
result.Reserve(bstr.GetLength());
for (char c : bstr)
result.InsertAtBack(static_cast<wchar_t>(c & 0xff));
return result;
}
// static
WideString WideString::FromDefANSI(ByteStringView bstr) {
size_t dest_len = FX_MultiByteToWideChar(FX_CodePage::kDefANSI, bstr, {});
if (!dest_len)
return WideString();
WideString wstr;
{
// Span's lifetime must end before ReleaseBuffer() below.
pdfium::span<wchar_t> dest_buf = wstr.GetBuffer(dest_len);
FX_MultiByteToWideChar(FX_CodePage::kDefANSI, bstr, dest_buf);
}
wstr.ReleaseBuffer(dest_len);
return wstr;
}
// static
WideString WideString::FromUTF8(ByteStringView str) {
return UTF8Decode(str);
}
// static
WideString WideString::FromUTF16LE(pdfium::span<const uint8_t> data) {
if (data.empty()) {
return WideString();
}
WideString result;
size_t length = 0;
{
// Span's lifetime must end before ReleaseBuffer() below.
pdfium::span<wchar_t> buf = result.GetBuffer(data.size() / 2);
for (size_t i = 0; i + 1 < data.size(); i += 2) {
buf[length++] = data[i] | data[i + 1] << 8;
}
#if defined(WCHAR_T_IS_32_BIT)
length = FuseSurrogates(buf.first(length));
#endif
}
result.ReleaseBuffer(length);
return result;
}
WideString WideString::FromUTF16BE(pdfium::span<const uint8_t> data) {
if (data.empty()) {
return WideString();
}
WideString result;
size_t length = 0;
{
// Span's lifetime must end before ReleaseBuffer() below.
pdfium::span<wchar_t> buf = result.GetBuffer(data.size() / 2);
for (size_t i = 0; i + 1 < data.size(); i += 2) {
buf[length++] = data[i] << 8 | data[i + 1];
}
#if defined(WCHAR_T_IS_32_BIT)
length = FuseSurrogates(buf.first(length));
#endif
}
result.ReleaseBuffer(length);
return result;
}
int WideString::Compare(const wchar_t* str) const {
if (m_pData)
return str ? wcscmp(m_pData->m_String, str) : 1;
return (!str || str[0] == 0) ? 0 : -1;
}
int WideString::Compare(const WideString& str) const {
if (!m_pData)
return str.m_pData ? -1 : 0;
if (!str.m_pData)
return 1;
size_t this_len = m_pData->m_nDataLength;
size_t that_len = str.m_pData->m_nDataLength;
size_t min_len = std::min(this_len, that_len);
// SAFTEY: Comparison limited to minimum length of either argument.
int result = UNSAFE_BUFFERS(
FXSYS_wmemcmp(m_pData->m_String, str.m_pData->m_String, min_len));
if (result != 0)
return result;
if (this_len == that_len)
return 0;
return this_len < that_len ? -1 : 1;
}
int WideString::CompareNoCase(const wchar_t* str) const {
if (m_pData)
return str ? FXSYS_wcsicmp(m_pData->m_String, str) : 1;
return (!str || str[0] == 0) ? 0 : -1;
}
void WideString::TrimWhitespace() {
TrimWhitespaceBack();
TrimWhitespaceFront();
}
void WideString::TrimWhitespaceFront() {
TrimFront(kWideTrimChars);
}
void WideString::TrimWhitespaceBack() {
TrimBack(kWideTrimChars);
}
int WideString::GetInteger() const {
return m_pData ? FXSYS_wtoi(m_pData->m_String) : 0;
}
std::wostream& operator<<(std::wostream& os, const WideString& str) {
return os.write(str.c_str(), str.GetLength());
}
std::ostream& operator<<(std::ostream& os, const WideString& str) {
os << str.ToUTF8();
return os;
}
std::wostream& operator<<(std::wostream& os, WideStringView str) {
return os.write(str.unterminated_c_str(), str.GetLength());
}
std::ostream& operator<<(std::ostream& os, WideStringView str) {
os << FX_UTF8Encode(str);
return os;
}
} // namespace fxcrt
uint32_t FX_HashCode_GetW(WideStringView str) {
uint32_t dwHashCode = 0;
for (WideStringView::UnsignedType c : str)
dwHashCode = 1313 * dwHashCode + c;
return dwHashCode;
}
uint32_t FX_HashCode_GetLoweredW(WideStringView str) {
uint32_t dwHashCode = 0;
for (wchar_t c : str) // match FXSYS_towlower() arg type.
dwHashCode = 1313 * dwHashCode + FXSYS_towlower(c);
return dwHashCode;
}