wxWidgets/include/wx/strconv.h

///////////////////////////////////////////////////////////////////////////////
// Name:        strconv.h
// Purpose:     conversion routines for char sets any Unicode
// Author:      Ove Kaaven, Robert Roebling, Vadim Zeitlin
// Modified by:
// Created:     29/01/98
// RCS-ID:      $Id$
// Copyright:   (c) 1998 Ove Kaaven, Robert Roebling
//              (c) 1998-2006 Vadim Zeitlin
// Licence:     wxWindows licence
///////////////////////////////////////////////////////////////////////////////

#ifndef _WX_STRCONV_H_
#define _WX_STRCONV_H_

#include "wx/defs.h"
#include "wx/chartype.h"
#include "wx/buffer.h"

#ifdef __DIGITALMARS__
#include "typeinfo.h"
#endif

#if defined(__VISAGECPP__) && __IBMCPP__ >= 400
#  undef __BSEXCPT__
#endif

#include <stdlib.h>

#if wxUSE_WCHAR_T

// the error value returned by wxMBConv methods
#define wxCONV_FAILED ((size_t)-1)

// the default value for some length parameters meaning that the string is
// NUL-terminated
#define wxNO_LEN ((size_t)-1)

// ----------------------------------------------------------------------------
// wxMBConv (abstract base class for conversions)
// ----------------------------------------------------------------------------

// When deriving a new class from wxMBConv you must reimplement ToWChar() and
// FromWChar() methods which are not pure virtual only for historical reasons,
// don't let the fact that the existing classes implement MB2WC/WC2MB() instead
// confuse you.
//
// You also have to implement Clone() to allow copying the conversions
// polymorphically.
//
// And you might need to override GetMBNulLen() as well.
class WXDLLIMPEXP_BASE wxMBConv
{
public:
    // The functions doing actual conversion from/to narrow to/from wide
    // character strings.
    //
    // On success, the return value is the length (i.e. the number of
    // characters, not bytes) of the converted string including any trailing
    // L'\0' or (possibly multiple) '\0'(s). If the conversion fails or if
    // there is not enough space for everything, including the trailing NUL
    // character(s), in the output buffer, wxCONV_FAILED is returned.
    //
    // In the special case when dstLen is 0 (outputBuf may be NULL then) the
    // return value is the length of the needed buffer but nothing happens
    // otherwise. If srcLen is wxNO_LEN, the entire string, up to and
    // including the trailing NUL(s), is converted, otherwise exactly srcLen
    // bytes are.
    //
    // Typical usage:
    //
    //          size_t dstLen = conv.ToWChar(NULL, 0, src);
    //          if ( dstLen != wxCONV_FAILED )
    //              ... handle error ...
    //          wchar_t *wbuf = new wchar_t[dstLen];
    //          conv.ToWChar(wbuf, dstLen, src);
    //
    virtual size_t ToWChar(wchar_t *dst, size_t dstLen,
                           const char *src, size_t srcLen = wxNO_LEN) const;

    virtual size_t FromWChar(char *dst, size_t dstLen,
                             const wchar_t *src, size_t srcLen = wxNO_LEN) const;


    // Convenience functions for translating NUL-terminated strings: returns
    // the buffer containing the converted string or NULL pointer if the
    // conversion failed.
    const wxWCharBuffer cMB2WC(const char *in) const;
    const wxCharBuffer cWC2MB(const wchar_t *in) const;

    // Convenience functions for converting strings which may contain embedded
    // NULs and don't have to be NUL-terminated.
    //
    // inLen is the length of the buffer including trailing NUL if any: if the
    // last 4 bytes of the buffer are all NULs, these functions are more
    // efficient as they avoid copying the string, but otherwise a copy is made
    // internally which could be quite bad for (very) long strings.
    //
    // outLen receives, if not NULL, the length of the converted string or 0 if
    // the conversion failed (returning 0 and not -1 in this case makes it
    // difficult to distinguish between failed conversion and empty input but
    // this is done for backwards compatibility)
    const wxWCharBuffer
        cMB2WC(const char *in, size_t inLen, size_t *outLen) const;
    const wxCharBuffer
        cWC2MB(const wchar_t *in, size_t inLen, size_t *outLen) const;

    // convenience functions for converting MB or WC to/from wxWin default
#if wxUSE_UNICODE
    const wxWCharBuffer cMB2WX(const char *psz) const { return cMB2WC(psz); }
    const wxCharBuffer cWX2MB(const wchar_t *psz) const { return cWC2MB(psz); }
    const wchar_t* cWC2WX(const wchar_t *psz) const { return psz; }
    const wchar_t* cWX2WC(const wchar_t *psz) const { return psz; }
#else // ANSI
    const char* cMB2WX(const char *psz) const { return psz; }
    const char* cWX2MB(const char *psz) const { return psz; }
    const wxCharBuffer cWC2WX(const wchar_t *psz) const { return cWC2MB(psz); }
    const wxWCharBuffer cWX2WC(const char *psz) const { return cMB2WC(psz); }
#endif // Unicode/ANSI

    // this function is used in the implementation of cMB2WC() to distinguish
    // between the following cases:
    //
    //      a) var width encoding with strings terminated by a single NUL
    //         (usual multibyte encodings): return 1 in this case
    //      b) fixed width encoding with 2 bytes/char and so terminated by
    //         2 NULs (UTF-16/UCS-2 and variants): return 2 in this case
    //      c) fixed width encoding with 4 bytes/char and so terminated by
    //         4 NULs (UTF-32/UCS-4 and variants): return 4 in this case
    //
    // anything else is not supported currently and -1 should be returned
    virtual size_t GetMBNulLen() const { return 1; }

    // return the maximal value currently returned by GetMBNulLen() for any
    // encoding
    static size_t GetMaxMBNulLen() { return 4 /* for UTF-32 */; }

#if wxUSE_UNICODE_UTF8
    // return true if the converter's charset is UTF-8, i.e. char* strings
    // decoded using this object can be directly copied to wxString's internal
    // storage without converting to WC and than back to UTF-8 MB string
    virtual bool IsUTF8() const { return false; }
#endif

    // The old conversion functions. The existing classes currently mostly
    // implement these ones but we're in transition to using To/FromWChar()
    // instead and any new classes should implement just the new functions.
    // For now, however, we provide default implementation of To/FromWChar() in
    // this base class in terms of MB2WC/WC2MB() to avoid having to rewrite all
    // the conversions at once.
    //
    // On success, the return value is the length (i.e. the number of
    // characters, not bytes) not counting the trailing NUL(s) of the converted
    // string. On failure, (size_t)-1 is returned. In the special case when
    // outputBuf is NULL the return value is the same one but nothing is
    // written to the buffer.
    //
    // Note that outLen is the length of the output buffer, not the length of
    // the input (which is always supposed to be terminated by one or more
    // NULs, as appropriate for the encoding)!
    virtual size_t MB2WC(wchar_t *out, const char *in, size_t outLen) const;
    virtual size_t WC2MB(char *out, const wchar_t *in, size_t outLen) const;


    // make a heap-allocated copy of this object
    virtual wxMBConv *Clone() const = 0;

    // virtual dtor for any base class
    virtual ~wxMBConv();
};

// ----------------------------------------------------------------------------
// wxMBConvLibc uses standard mbstowcs() and wcstombs() functions for
//              conversion (hence it depends on the current locale)
// ----------------------------------------------------------------------------

class WXDLLIMPEXP_BASE wxMBConvLibc : public wxMBConv
{
public:
    virtual size_t MB2WC(wchar_t *outputBuf, const char *psz, size_t outputSize) const;
    virtual size_t WC2MB(char *outputBuf, const wchar_t *psz, size_t outputSize) const;

    virtual wxMBConv *Clone() const { return new wxMBConvLibc; }

#if wxUSE_UNICODE_UTF8
    virtual bool IsUTF8() const { return wxLocaleIsUtf8; }
#endif
};

#ifdef __UNIX__

// ----------------------------------------------------------------------------
// wxConvBrokenFileNames is made for Unix in Unicode mode when
// files are accidentally written in an encoding which is not
// the system encoding. Typically, the system encoding will be
// UTF8 but there might be files stored in ISO8859-1 on disk.
// ----------------------------------------------------------------------------

class WXDLLIMPEXP_BASE wxConvBrokenFileNames : public wxMBConv
{
public:
    wxConvBrokenFileNames(const wxChar *charset);
    wxConvBrokenFileNames(const wxConvBrokenFileNames& conv)
        : wxMBConv(),
          m_conv(conv.m_conv ? conv.m_conv->Clone() : NULL)
    {
    }
    virtual ~wxConvBrokenFileNames() { delete m_conv; }

    virtual size_t MB2WC(wchar_t *out, const char *in, size_t outLen) const
    {
        return m_conv->MB2WC(out, in, outLen);
    }

    virtual size_t WC2MB(char *out, const wchar_t *in, size_t outLen) const
    {
        return m_conv->WC2MB(out, in, outLen);
    }

    virtual size_t GetMBNulLen() const
    {
        // cast needed to call a private function
        return m_conv->GetMBNulLen();
    }

#if wxUSE_UNICODE_UTF8
    virtual bool IsUTF8() const { return m_conv->IsUTF8(); }
#endif

    virtual wxMBConv *Clone() const { return new wxConvBrokenFileNames(*this); }

private:
    // the conversion object we forward to
    wxMBConv *m_conv;

    DECLARE_NO_ASSIGN_CLASS(wxConvBrokenFileNames)
};

#endif // __UNIX__

// ----------------------------------------------------------------------------
// wxMBConvUTF7 (for conversion using UTF7 encoding)
// ----------------------------------------------------------------------------

class WXDLLIMPEXP_BASE wxMBConvUTF7 : public wxMBConv
{
public:
    virtual size_t MB2WC(wchar_t *outputBuf, const char *psz, size_t outputSize) const;
    virtual size_t WC2MB(char *outputBuf, const wchar_t *psz, size_t outputSize) const;

    virtual wxMBConv *Clone() const { return new wxMBConvUTF7; }
};

// ----------------------------------------------------------------------------
// wxMBConvUTF8 (for conversion using UTF8 encoding)
// ----------------------------------------------------------------------------

class WXDLLIMPEXP_BASE wxMBConvUTF8 : public wxMBConv
{
public:
    // FIXME-UTF8: split this class into multiple classes, one strict and
    //             other lossy (PUA, OCTAL mappings)
    enum
    {
        MAP_INVALID_UTF8_NOT = 0,
        MAP_INVALID_UTF8_TO_PUA = 1,
        MAP_INVALID_UTF8_TO_OCTAL = 2
    };

    wxMBConvUTF8(int options = MAP_INVALID_UTF8_NOT) : m_options(options) { }
    virtual size_t MB2WC(wchar_t *outputBuf, const char *psz, size_t outputSize) const;
    virtual size_t WC2MB(char *outputBuf, const wchar_t *psz, size_t outputSize) const;

    virtual wxMBConv *Clone() const { return new wxMBConvUTF8(m_options); }

#if wxUSE_UNICODE_UTF8
    // NB: other mapping modes are not, strictly speaking, UTF-8, so we can't
    //     take the shortcut in that case
    virtual bool IsUTF8() const { return m_options == MAP_INVALID_UTF8_NOT; }
#endif

private:
    int m_options;
};

// ----------------------------------------------------------------------------
// wxMBConvUTF16Base: for both LE and BE variants
// ----------------------------------------------------------------------------

class WXDLLIMPEXP_BASE wxMBConvUTF16Base : public wxMBConv
{
public:
    enum { BYTES_PER_CHAR = 2 };

    virtual size_t GetMBNulLen() const { return BYTES_PER_CHAR; }

protected:
    // return the length of the buffer using srcLen if it's not wxNO_LEN and
    // computing the length ourselves if it is; also checks that the length is
    // even if specified as we need an entire number of UTF-16 characters and
    // returns wxNO_LEN which indicates error if it is odd
    static size_t GetLength(const char *src, size_t srcLen);
};

// ----------------------------------------------------------------------------
// wxMBConvUTF16LE (for conversion using UTF16 Little Endian encoding)
// ----------------------------------------------------------------------------

class WXDLLIMPEXP_BASE wxMBConvUTF16LE : public wxMBConvUTF16Base
{
public:
    virtual size_t ToWChar(wchar_t *dst, size_t dstLen,
                           const char *src, size_t srcLen = wxNO_LEN) const;
    virtual size_t FromWChar(char *dst, size_t dstLen,
                             const wchar_t *src, size_t srcLen = wxNO_LEN) const;
    virtual wxMBConv *Clone() const { return new wxMBConvUTF16LE; }
};

// ----------------------------------------------------------------------------
// wxMBConvUTF16BE (for conversion using UTF16 Big Endian encoding)
// ----------------------------------------------------------------------------

class WXDLLIMPEXP_BASE wxMBConvUTF16BE : public wxMBConvUTF16Base
{
public:
    virtual size_t ToWChar(wchar_t *dst, size_t dstLen,
                           const char *src, size_t srcLen = wxNO_LEN) const;
    virtual size_t FromWChar(char *dst, size_t dstLen,
                             const wchar_t *src, size_t srcLen = wxNO_LEN) const;
    virtual wxMBConv *Clone() const { return new wxMBConvUTF16BE; }
};

// ----------------------------------------------------------------------------
// wxMBConvUTF32Base: base class for both LE and BE variants
// ----------------------------------------------------------------------------

class WXDLLIMPEXP_BASE wxMBConvUTF32Base : public wxMBConv
{
public:
    enum { BYTES_PER_CHAR = 4 };

    virtual size_t GetMBNulLen() const { return BYTES_PER_CHAR; }

protected:
    // this is similar to wxMBConvUTF16Base method with the same name except
    // that, of course, it verifies that length is divisible by 4 if given and
    // not by 2
    static size_t GetLength(const char *src, size_t srcLen);
};

// ----------------------------------------------------------------------------
// wxMBConvUTF32LE (for conversion using UTF32 Little Endian encoding)
// ----------------------------------------------------------------------------

class WXDLLIMPEXP_BASE wxMBConvUTF32LE : public wxMBConvUTF32Base
{
public:
    virtual size_t ToWChar(wchar_t *dst, size_t dstLen,
                           const char *src, size_t srcLen = wxNO_LEN) const;
    virtual size_t FromWChar(char *dst, size_t dstLen,
                             const wchar_t *src, size_t srcLen = wxNO_LEN) const;
    virtual wxMBConv *Clone() const { return new wxMBConvUTF32LE; }
};

// ----------------------------------------------------------------------------
// wxMBConvUTF32BE (for conversion using UTF32 Big Endian encoding)
// ----------------------------------------------------------------------------

class WXDLLIMPEXP_BASE wxMBConvUTF32BE : public wxMBConvUTF32Base
{
public:
    virtual size_t ToWChar(wchar_t *dst, size_t dstLen,
                           const char *src, size_t srcLen = wxNO_LEN) const;
    virtual size_t FromWChar(char *dst, size_t dstLen,
                             const wchar_t *src, size_t srcLen = wxNO_LEN) const;
    virtual wxMBConv *Clone() const { return new wxMBConvUTF32BE; }
};

// ----------------------------------------------------------------------------
// wxCSConv (for conversion based on loadable char sets)
// ----------------------------------------------------------------------------

#include "wx/fontenc.h"

class WXDLLIMPEXP_BASE wxCSConv : public wxMBConv
{
public:
    // we can be created either from charset name or from an encoding constant
    // but we can't have both at once
    wxCSConv(const wxChar *charset);
    wxCSConv(wxFontEncoding encoding);

    wxCSConv(const wxCSConv& conv);
    virtual ~wxCSConv();

    wxCSConv& operator=(const wxCSConv& conv);

    virtual size_t ToWChar(wchar_t *dst, size_t dstLen,
                           const char *src, size_t srcLen = wxNO_LEN) const;
    virtual size_t FromWChar(char *dst, size_t dstLen,
                             const wchar_t *src, size_t srcLen = wxNO_LEN) const;
    virtual size_t MB2WC(wchar_t *outputBuf, const char *psz, size_t outputSize) const;
    virtual size_t WC2MB(char *outputBuf, const wchar_t *psz, size_t outputSize) const;
    virtual size_t GetMBNulLen() const;

#if wxUSE_UNICODE_UTF8
    virtual bool IsUTF8() const;
#endif

    virtual wxMBConv *Clone() const { return new wxCSConv(*this); }

    void Clear();

    // return true if the conversion could be initilized successfully
    bool IsOk() const;

private:
    // common part of all ctors
    void Init();

    // creates m_convReal if necessary
    void CreateConvIfNeeded() const;

    // do create m_convReal (unconditionally)
    wxMBConv *DoCreate() const;

    // set the name (may be only called when m_name == NULL), makes copy of
    // charset string
    void SetName(const wxChar *charset);


    // note that we can't use wxString here because of compilation
    // dependencies: we're included from wx/string.h
    wxChar *m_name;
    wxFontEncoding m_encoding;

    // use CreateConvIfNeeded() before accessing m_convReal!
    wxMBConv *m_convReal;
    bool m_deferred;
};


// ----------------------------------------------------------------------------
// declare predefined conversion objects
// ----------------------------------------------------------------------------

// Note: this macro is an implementation detail (see the comment in
// strconv.cpp). The wxGet_XXX() and wxGet_XXXPtr() functions shouldn't be
// used by user code and neither should XXXPtr, use the wxConvXXX macro
// instead.
#define WX_DECLARE_GLOBAL_CONV(klass, name)                             \
    extern WXDLLIMPEXP_DATA_BASE(klass*) name##Ptr;                     \
    extern WXDLLIMPEXP_BASE klass* wxGet_##name##Ptr();                 \
    inline klass& wxGet_##name()                                        \
    {                                                                   \
        if ( !name##Ptr )                                               \
            name##Ptr = wxGet_##name##Ptr();                            \
        return *name##Ptr;                                              \
    }


// conversion to be used with all standard functions affected by locale, e.g.
// strtol(), strftime(), ...
WX_DECLARE_GLOBAL_CONV(wxMBConv, wxConvLibc)
#define wxConvLibc wxGet_wxConvLibc()

// conversion ISO-8859-1/UTF-7/UTF-8 <-> wchar_t
WX_DECLARE_GLOBAL_CONV(wxCSConv, wxConvISO8859_1)
#define wxConvISO8859_1 wxGet_wxConvISO8859_1()

WX_DECLARE_GLOBAL_CONV(wxMBConvUTF8, wxConvUTF8)
#define wxConvUTF8 wxGet_wxConvUTF8()

WX_DECLARE_GLOBAL_CONV(wxMBConvUTF7, wxConvUTF7)
#define wxConvUTF7 wxGet_wxConvUTF7()

// conversion used for the file names on the systems where they're not Unicode
// (basically anything except Windows)
//
// this is used by all file functions, can be changed by the application
//
// by default UTF-8 under Mac OS X and wxConvLibc elsewhere (but it's not used
// under Windows normally)
extern WXDLLIMPEXP_DATA_BASE(wxMBConv *) wxConvFileName;

// backwards compatible define
#define wxConvFile (*wxConvFileName)

// the current conversion object, may be set to any conversion, is used by
// default in a couple of places inside wx (initially same as wxConvLibc)
extern WXDLLIMPEXP_DATA_BASE(wxMBConv *) wxConvCurrent;

// the conversion corresponding to the current locale
WX_DECLARE_GLOBAL_CONV(wxCSConv, wxConvLocal)
#define wxConvLocal wxGet_wxConvLocal()

// the conversion corresponding to the encoding of the standard UI elements
//
// by default this is the same as wxConvLocal but may be changed if the program
// needs to use a fixed encoding
extern WXDLLIMPEXP_DATA_BASE(wxMBConv *) wxConvUI;

#undef WX_DECLARE_GLOBAL_CONV

// ----------------------------------------------------------------------------
// endianness-dependent conversions
// ----------------------------------------------------------------------------

#ifdef WORDS_BIGENDIAN
    typedef wxMBConvUTF16BE wxMBConvUTF16;
    typedef wxMBConvUTF32BE wxMBConvUTF32;
#else
    typedef wxMBConvUTF16LE wxMBConvUTF16;
    typedef wxMBConvUTF32LE wxMBConvUTF32;
#endif

// ----------------------------------------------------------------------------
// filename conversion macros
// ----------------------------------------------------------------------------

// filenames are multibyte on Unix and widechar on Windows
#if defined(__UNIX__) || defined(__WXMAC__)
    #define wxMBFILES 1
#else
    #define wxMBFILES 0
#endif

#if wxMBFILES && wxUSE_UNICODE
    #define wxFNCONV(name) wxConvFileName->cWX2MB(name)
    #define wxFNSTRINGCAST wxMBSTRINGCAST
#else
#if defined( __WXOSX__ ) && wxMBFILES
    #define wxFNCONV(name) wxConvFileName->cWC2MB( wxConvLocal.cWX2WC(name) )
#else
    #define wxFNCONV(name) name
#endif
    #define wxFNSTRINGCAST WXSTRINGCAST
#endif

#else // !wxUSE_WCHAR_T

// ----------------------------------------------------------------------------
// stand-ins in absence of wchar_t
// ----------------------------------------------------------------------------

class WXDLLIMPEXP_BASE wxMBConv
{
public:
    const char* cMB2WX(const char *psz) const { return psz; }
    const char* cWX2MB(const char *psz) const { return psz; }
};

#define wxConvFile wxConvLocal

extern WXDLLIMPEXP_DATA_BASE(wxMBConv) wxConvLibc,
                                       wxConvLocal,
                                       wxConvISO8859_1,
                                       wxConvUTF8;
extern WXDLLIMPEXP_DATA_BASE(wxMBConv *) wxConvCurrent;

#define wxFNCONV(name) name
#define wxFNSTRINGCAST WXSTRINGCAST

#endif
  // wxUSE_WCHAR_T

// ----------------------------------------------------------------------------
// macros for the most common conversions
// ----------------------------------------------------------------------------

#if wxUSE_UNICODE
    #define wxConvertWX2MB(s)   wxConvCurrent->cWX2MB(s)
    #define wxConvertMB2WX(s)   wxConvCurrent->cMB2WX(s)

    // these functions should be used when the conversions really, really have
    // to succeed (usually because we pass their results to a standard C
    // function which would crash if we passed NULL to it), so these functions
    // always return a valid pointer if their argument is non-NULL

    // this function safety is achieved by trying wxConvLibc first, wxConvUTF8
    // next if it fails and, finally, wxConvISO8859_1 which always succeeds
    extern WXDLLIMPEXP_BASE wxWCharBuffer wxSafeConvertMB2WX(const char *s);

    // this function uses wxConvLibc and wxConvUTF8(MAP_INVALID_UTF8_TO_OCTAL)
    // if it fails
    extern WXDLLIMPEXP_BASE wxCharBuffer wxSafeConvertWX2MB(const wchar_t *ws);
#else // ANSI
    // no conversions to do
    #define wxConvertWX2MB(s)   (s)
    #define wxConvertMB2WX(s)   (s)
    #define wxSafeConvertMB2WX(s) (s)
    #define wxSafeConvertWX2MB(s) (s)
#endif // Unicode/ANSI

#endif // _WX_STRCONV_H_