wxWidgets/include/wx/unichar.h
Vadim Zeitlin 1540361e75 Avoid warnings about conversion to wxUint16 in wxUniChar code
This conversion is intentional, so suppress the -Wconversion warning
given by g++ 7 (if this warning is enabled) with an explicit cast.
2018-03-06 16:00:47 +01:00

376 lines
13 KiB
C++

///////////////////////////////////////////////////////////////////////////////
// Name: wx/unichar.h
// Purpose: wxUniChar and wxUniCharRef classes
// Author: Vaclav Slavik
// Created: 2007-03-19
// Copyright: (c) 2007 REA Elektronik GmbH
// Licence: wxWindows licence
///////////////////////////////////////////////////////////////////////////////
#ifndef _WX_UNICHAR_H_
#define _WX_UNICHAR_H_
#include "wx/defs.h"
#include "wx/chartype.h"
#include "wx/stringimpl.h"
#include <algorithm> // only for std::swap specialization below
class WXDLLIMPEXP_FWD_BASE wxUniCharRef;
class WXDLLIMPEXP_FWD_BASE wxString;
// This class represents single Unicode character. It can be converted to
// and from char or wchar_t and implements commonly used character operations.
class WXDLLIMPEXP_BASE wxUniChar
{
public:
// NB: this is not wchar_t on purpose, it needs to represent the entire
// Unicode code points range and wchar_t may be too small for that
// (e.g. on Win32 where wchar_t* is encoded in UTF-16)
typedef wxUint32 value_type;
wxUniChar() : m_value(0) {}
// Create the character from 8bit character value encoded in the current
// locale's charset.
wxUniChar(char c) { m_value = From8bit(c); }
wxUniChar(unsigned char c) { m_value = From8bit((char)c); }
#define wxUNICHAR_DEFINE_CTOR(type) \
wxUniChar(type c) { m_value = (value_type)c; }
wxDO_FOR_INT_TYPES(wxUNICHAR_DEFINE_CTOR)
#undef wxUNICHAR_DEFINE_CTOR
wxUniChar(const wxUniCharRef& c);
// Returns Unicode code point value of the character
value_type GetValue() const { return m_value; }
#if wxUSE_UNICODE_UTF8
// buffer for single UTF-8 character
struct Utf8CharBuffer
{
char data[5];
operator const char*() const { return data; }
};
// returns the character encoded as UTF-8
// (NB: implemented in stringops.cpp)
Utf8CharBuffer AsUTF8() const;
#endif // wxUSE_UNICODE_UTF8
// Returns true if the character is an ASCII character:
bool IsAscii() const { return m_value < 0x80; }
// Returns true if the character is representable as a single byte in the
// current locale encoding and return this byte in output argument c (which
// must be non-NULL)
bool GetAsChar(char *c) const
{
#if wxUSE_UNICODE
if ( !IsAscii() )
{
#if !wxUSE_UTF8_LOCALE_ONLY
if ( GetAsHi8bit(m_value, c) )
return true;
#endif // !wxUSE_UTF8_LOCALE_ONLY
return false;
}
#endif // wxUSE_UNICODE
*c = wx_truncate_cast(char, m_value);
return true;
}
// Returns true if the character is a BMP character:
static bool IsBMP(wxUint32 value) { return value < 0x10000; }
// Returns true if the character is a supplementary character:
static bool IsSupplementary(wxUint32 value) { return 0x10000 <= value && value < 0x110000; }
// Returns the high surrogate code unit for the supplementary character
static wxUint16 HighSurrogate(wxUint32 value)
{
wxASSERT_MSG(IsSupplementary(value), "wxUniChar::HighSurrogate() must be called on a supplementary character");
return static_cast<wxUint16>(0xD800 | ((value - 0x10000) >> 10));
}
// Returns the low surrogate code unit for the supplementary character
static wxUint16 LowSurrogate(wxUint32 value)
{
wxASSERT_MSG(IsSupplementary(value), "wxUniChar::LowSurrogate() must be called on a supplementary character");
return static_cast<wxUint16>(0xDC00 | ((value - 0x10000) & 0x03FF));
}
// Returns true if the character is a BMP character:
bool IsBMP() const { return IsBMP(m_value); }
// Returns true if the character is a supplementary character:
bool IsSupplementary() const { return IsSupplementary(m_value); }
// Returns the high surrogate code unit for the supplementary character
wxUint16 HighSurrogate() const { return HighSurrogate(m_value); }
// Returns the low surrogate code unit for the supplementary character
wxUint16 LowSurrogate() const { return LowSurrogate(m_value); }
// Conversions to char and wchar_t types: all of those are needed to be
// able to pass wxUniChars to verious standard narrow and wide character
// functions
operator char() const { return To8bit(m_value); }
operator unsigned char() const { return (unsigned char)To8bit(m_value); }
#define wxUNICHAR_DEFINE_OPERATOR_PAREN(type) \
operator type() const { return (type)m_value; }
wxDO_FOR_INT_TYPES(wxUNICHAR_DEFINE_OPERATOR_PAREN)
#undef wxUNICHAR_DEFINE_OPERATOR_PAREN
// We need this operator for the "*p" part of expressions like "for (
// const_iterator p = begin() + nStart; *p; ++p )". In this case,
// compilation would fail without it because the conversion to bool would
// be ambiguous (there are all these int types conversions...). (And adding
// operator unspecified_bool_type() would only makes the ambiguity worse.)
operator bool() const { return m_value != 0; }
bool operator!() const { return !((bool)*this); }
// And this one is needed by some (not all, but not using ifdefs makes the
// code easier) compilers to parse "str[0] && *p" successfully
bool operator&&(bool v) const { return (bool)*this && v; }
// Assignment operators:
wxUniChar& operator=(const wxUniChar& c) { if (&c != this) m_value = c.m_value; return *this; }
wxUniChar& operator=(const wxUniCharRef& c);
wxUniChar& operator=(char c) { m_value = From8bit(c); return *this; }
wxUniChar& operator=(unsigned char c) { m_value = From8bit((char)c); return *this; }
#define wxUNICHAR_DEFINE_OPERATOR_EQUAL(type) \
wxUniChar& operator=(type c) { m_value = (value_type)c; return *this; }
wxDO_FOR_INT_TYPES(wxUNICHAR_DEFINE_OPERATOR_EQUAL)
#undef wxUNICHAR_DEFINE_OPERATOR_EQUAL
// Comparison operators:
#define wxDEFINE_UNICHAR_CMP_WITH_INT(T, op) \
bool operator op(T c) const { return m_value op (value_type)c; }
// define the given comparison operator for all the types
#define wxDEFINE_UNICHAR_OPERATOR(op) \
bool operator op(const wxUniChar& c) const { return m_value op c.m_value; }\
bool operator op(char c) const { return m_value op From8bit(c); } \
bool operator op(unsigned char c) const { return m_value op From8bit((char)c); } \
wxDO_FOR_INT_TYPES_1(wxDEFINE_UNICHAR_CMP_WITH_INT, op)
wxFOR_ALL_COMPARISONS(wxDEFINE_UNICHAR_OPERATOR)
#undef wxDEFINE_UNICHAR_OPERATOR
#undef wxDEFINE_UNCHAR_CMP_WITH_INT
// this is needed for expressions like 'Z'-c
int operator-(const wxUniChar& c) const { return m_value - c.m_value; }
int operator-(char c) const { return m_value - From8bit(c); }
int operator-(unsigned char c) const { return m_value - From8bit((char)c); }
int operator-(wchar_t c) const { return m_value - (value_type)c; }
private:
// notice that we implement these functions inline for 7-bit ASCII
// characters purely for performance reasons
static value_type From8bit(char c)
{
#if wxUSE_UNICODE
if ( (unsigned char)c < 0x80 )
return c;
return FromHi8bit(c);
#else
return c;
#endif
}
static char To8bit(value_type c)
{
#if wxUSE_UNICODE
if ( c < 0x80 )
return wx_truncate_cast(char, c);
return ToHi8bit(c);
#else
return wx_truncate_cast(char, c);
#endif
}
// helpers of the functions above called to deal with non-ASCII chars
static value_type FromHi8bit(char c);
static char ToHi8bit(value_type v);
static bool GetAsHi8bit(value_type v, char *c);
private:
value_type m_value;
};
// Writeable reference to a character in wxString.
//
// This class can be used in the same way wxChar is used, except that changing
// its value updates the underlying string object.
class WXDLLIMPEXP_BASE wxUniCharRef
{
private:
typedef wxStringImpl::iterator iterator;
// create the reference
#if wxUSE_UNICODE_UTF8
wxUniCharRef(wxString& str, iterator pos) : m_str(str), m_pos(pos) {}
#else
wxUniCharRef(iterator pos) : m_pos(pos) {}
#endif
public:
// NB: we have to make this public, because we don't have wxString
// declaration available here and so can't declare wxString::iterator
// as friend; so at least don't use a ctor but a static function
// that must be used explicitly (this is more than using 'explicit'
// keyword on ctor!):
#if wxUSE_UNICODE_UTF8
static wxUniCharRef CreateForString(wxString& str, iterator pos)
{ return wxUniCharRef(str, pos); }
#else
static wxUniCharRef CreateForString(iterator pos)
{ return wxUniCharRef(pos); }
#endif
wxUniChar::value_type GetValue() const { return UniChar().GetValue(); }
#if wxUSE_UNICODE_UTF8
wxUniChar::Utf8CharBuffer AsUTF8() const { return UniChar().AsUTF8(); }
#endif // wxUSE_UNICODE_UTF8
bool IsAscii() const { return UniChar().IsAscii(); }
bool GetAsChar(char *c) const { return UniChar().GetAsChar(c); }
bool IsBMP() const { return UniChar().IsBMP(); }
bool IsSupplementary() const { return UniChar().IsSupplementary(); }
wxUint16 HighSurrogate() const { return UniChar().HighSurrogate(); }
wxUint16 LowSurrogate() const { return UniChar().LowSurrogate(); }
// Assignment operators:
#if wxUSE_UNICODE_UTF8
wxUniCharRef& operator=(const wxUniChar& c);
#else
wxUniCharRef& operator=(const wxUniChar& c) { *m_pos = c; return *this; }
#endif
wxUniCharRef& operator=(const wxUniCharRef& c)
{ if (&c != this) *this = c.UniChar(); return *this; }
#define wxUNICHAR_REF_DEFINE_OPERATOR_EQUAL(type) \
wxUniCharRef& operator=(type c) { return *this = wxUniChar(c); }
wxDO_FOR_CHAR_INT_TYPES(wxUNICHAR_REF_DEFINE_OPERATOR_EQUAL)
#undef wxUNICHAR_REF_DEFINE_OPERATOR_EQUAL
// Conversions to the same types as wxUniChar is convertible too:
#define wxUNICHAR_REF_DEFINE_OPERATOR_PAREN(type) \
operator type() const { return UniChar(); }
wxDO_FOR_CHAR_INT_TYPES(wxUNICHAR_REF_DEFINE_OPERATOR_PAREN)
#undef wxUNICHAR_REF_DEFINE_OPERATOR_PAREN
// see wxUniChar::operator bool etc. for explanation
operator bool() const { return (bool)UniChar(); }
bool operator!() const { return !UniChar(); }
bool operator&&(bool v) const { return UniChar() && v; }
#define wxDEFINE_UNICHARREF_CMP_WITH_INT(T, op) \
bool operator op(T c) const { return UniChar() op c; }
// Comparison operators:
#define wxDEFINE_UNICHARREF_OPERATOR(op) \
bool operator op(const wxUniCharRef& c) const { return UniChar() op c.UniChar(); }\
bool operator op(const wxUniChar& c) const { return UniChar() op c; } \
wxDO_FOR_CHAR_INT_TYPES_1(wxDEFINE_UNICHARREF_CMP_WITH_INT, op)
wxFOR_ALL_COMPARISONS(wxDEFINE_UNICHARREF_OPERATOR)
#undef wxDEFINE_UNICHARREF_OPERATOR
#undef wxDEFINE_UNICHARREF_CMP_WITH_INT
// for expressions like c-'A':
int operator-(const wxUniCharRef& c) const { return UniChar() - c.UniChar(); }
int operator-(const wxUniChar& c) const { return UniChar() - c; }
int operator-(char c) const { return UniChar() - c; }
int operator-(unsigned char c) const { return UniChar() - c; }
int operator-(wchar_t c) const { return UniChar() - c; }
private:
#if wxUSE_UNICODE_UTF8
wxUniChar UniChar() const;
#else
wxUniChar UniChar() const { return *m_pos; }
#endif
friend class WXDLLIMPEXP_FWD_BASE wxUniChar;
private:
// reference to the string and pointer to the character in string
#if wxUSE_UNICODE_UTF8
wxString& m_str;
#endif
iterator m_pos;
};
inline wxUniChar::wxUniChar(const wxUniCharRef& c)
{
m_value = c.UniChar().m_value;
}
inline wxUniChar& wxUniChar::operator=(const wxUniCharRef& c)
{
m_value = c.UniChar().m_value;
return *this;
}
// wxUniCharRef doesn't behave quite like a reference, notably because template
// deduction from wxUniCharRef doesn't yield wxUniChar as would have been the
// case if it were a real reference. This results in a number of problems and
// we can't fix all of them but we can at least provide a working swap() for
// it, instead of the default version which doesn't work because a "wrong" type
// is deduced.
namespace std
{
template <>
inline
void swap<wxUniCharRef>(wxUniCharRef& lhs, wxUniCharRef& rhs)
{
if ( &lhs != &rhs )
{
// The use of wxUniChar here is the crucial difference: in the default
// implementation, tmp would be wxUniCharRef and so assigning to lhs
// would modify it too. Here we make a real copy, not affected by
// changing lhs, instead.
wxUniChar tmp = lhs;
lhs = rhs;
rhs = tmp;
}
}
} // namespace std
// Comparison operators for the case when wxUniChar(Ref) is the second operand
// implemented in terms of member comparison functions
wxDEFINE_COMPARISONS_BY_REV(char, const wxUniChar&)
wxDEFINE_COMPARISONS_BY_REV(char, const wxUniCharRef&)
wxDEFINE_COMPARISONS_BY_REV(wchar_t, const wxUniChar&)
wxDEFINE_COMPARISONS_BY_REV(wchar_t, const wxUniCharRef&)
wxDEFINE_COMPARISONS_BY_REV(const wxUniChar&, const wxUniCharRef&)
// for expressions like c-'A':
inline int operator-(char c1, const wxUniCharRef& c2) { return -(c2 - c1); }
inline int operator-(const wxUniChar& c1, const wxUniCharRef& c2) { return -(c2 - c1); }
inline int operator-(wchar_t c1, const wxUniCharRef& c2) { return -(c2 - c1); }
#endif /* _WX_UNICHAR_H_ */