wxWidgets/include/wx/buffer.h

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///////////////////////////////////////////////////////////////////////////////
// Name: wx/buffer.h
// Purpose: auto buffer classes: buffers which automatically free memory
// Author: Vadim Zeitlin
// Modified by:
// Created: 12.04.99
// RCS-ID: $Id$
// Copyright: (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
// Licence: wxWindows licence
///////////////////////////////////////////////////////////////////////////////
#ifndef _WX_BUFFER_H
#define _WX_BUFFER_H
#include "wx/chartype.h"
#include "wx/wxcrtbase.h"
#ifndef __WXPALMOS5__
#include <stdlib.h> // malloc() and free()
#endif // ! __WXPALMOS5__
class WXDLLIMPEXP_FWD_BASE wxCStrData;
// ----------------------------------------------------------------------------
// Special classes for (wide) character strings: they use malloc/free instead
// of new/delete
// ----------------------------------------------------------------------------
// helpers used by wxCharTypeBuffer
namespace wxPrivate
{
struct UntypedBufferData
{
enum Kind
{
Owned,
NonOwned
};
UntypedBufferData(void *str, Kind kind = Owned)
: m_str(str), m_ref(1), m_owned(kind == Owned) {}
~UntypedBufferData()
{
if ( m_owned )
free(m_str);
}
void *m_str;
// "short" to have sizeof(Data)=8 on 32bit archs
unsigned short m_ref;
bool m_owned;
};
// this has to be defined inside the DLL (and not e.g. as a static variable
// inside an inline function) as otherwise MSVC gives link errors when the
// functions are effectively inlined (i.e. in non-debug build)
//
// NB: this is defined in string.cpp and not the (non-existent) buffer.cpp
extern WXDLLIMPEXP_DATA_BASE(UntypedBufferData * const) untypedNullDataPtr;
} // namespace wxPrivate
template <typename T>
class wxCharTypeBuffer
{
public:
typedef T CharType;
wxCharTypeBuffer(const CharType *str = NULL)
{
if ( str )
m_data = new Data(wxStrdup(str));
else
m_data = GetNullData();
}
wxCharTypeBuffer(size_t len)
{
m_data = new Data((CharType *)malloc((len + 1)*sizeof(CharType)));
m_data->Get()[len] = (CharType)0;
}
static const wxCharTypeBuffer CreateNonOwned(const CharType *str)
{
wxCharTypeBuffer buf;
if ( str )
buf.m_data = new Data(const_cast<CharType*>(str), Data::NonOwned);
return buf;
}
~wxCharTypeBuffer()
{
DecRef();
}
// NB: this method is only const for backward compatibility. It used to
// be needed for auto_ptr-like semantics of the copy ctor, but now
// that ref-counting is used, it's not really needed.
CharType *release() const
{
if ( m_data == GetNullData() )
return NULL;
wxASSERT_MSG( m_data->m_owned, _T("can't release non-owned buffer") );
wxASSERT_MSG( m_data->m_ref == 1, _T("can't release shared buffer") );
CharType * const p = m_data->Get();
wxCharTypeBuffer *self = const_cast<wxCharTypeBuffer*>(this);
self->m_data->Set(NULL);
self->DecRef();
return p;
}
void reset()
{
DecRef();
}
wxCharTypeBuffer(const wxCharTypeBuffer& src)
{
m_data = src.m_data;
IncRef();
}
wxCharTypeBuffer& operator=(const CharType *str)
{
DecRef();
if ( str )
m_data = new Data(wxStrdup(str));
return *this;
}
wxCharTypeBuffer& operator=(const wxCharTypeBuffer& src)
{
if ( &src == this )
return *this;
DecRef();
m_data = src.m_data;
IncRef();
return *this;
}
bool extend(size_t len)
{
wxASSERT_MSG( m_data->m_owned, _T("cannot extend non-owned buffer") );
wxASSERT_MSG( m_data->m_ref == 1, _T("can't extend shared buffer") );
CharType *str =
(CharType *)realloc(data(), (len + 1) * sizeof(CharType));
if ( !str )
return false;
if ( m_data == GetNullData() )
{
m_data = new Data(str);
}
else
{
m_data->Set(str);
m_data->m_owned = true;
}
return true;
}
CharType *data() { return m_data->Get(); }
const CharType *data() const { return m_data->Get(); }
operator const CharType *() const { return data(); }
CharType operator[](size_t n) const { return data()[n]; }
private:
// reference-counted data
struct Data : public wxPrivate::UntypedBufferData
{
Data(CharType *str, Kind kind = Owned)
: wxPrivate::UntypedBufferData(str, kind)
{
}
CharType *Get() const { return static_cast<CharType *>(m_str); }
void Set(CharType *str) { m_str = str; }
};
// placeholder for NULL string, to simplify this code
static Data *GetNullData()
{
return static_cast<Data *>(wxPrivate::untypedNullDataPtr);
}
void IncRef()
{
if ( m_data == GetNullData() ) // exception, not ref-counted
return;
m_data->m_ref++;
}
void DecRef()
{
if ( m_data == GetNullData() ) // exception, not ref-counted
return;
if ( --m_data->m_ref == 0 )
delete m_data;
m_data = GetNullData();
}
private:
Data *m_data;
};
WXDLLIMPEXP_TEMPLATE_INSTANCE_BASE( wxCharTypeBuffer<char> )
class wxCharBuffer : public wxCharTypeBuffer<char>
{
public:
typedef wxCharTypeBuffer<char> wxCharTypeBufferBase;
wxCharBuffer(const wxCharTypeBufferBase& buf)
: wxCharTypeBufferBase(buf) {}
wxCharBuffer(const CharType *str = NULL) : wxCharTypeBufferBase(str) {}
wxCharBuffer(size_t len) : wxCharTypeBufferBase(len) {}
wxCharBuffer(const wxCStrData& cstr);
};
#if wxUSE_WCHAR_T
WXDLLIMPEXP_TEMPLATE_INSTANCE_BASE( wxCharTypeBuffer<wchar_t> )
class wxWCharBuffer : public wxCharTypeBuffer<wchar_t>
{
public:
typedef wxCharTypeBuffer<wchar_t> wxCharTypeBufferBase;
wxWCharBuffer(const wxCharTypeBufferBase& buf)
: wxCharTypeBufferBase(buf) {}
wxWCharBuffer(const CharType *str = NULL) : wxCharTypeBufferBase(str) {}
wxWCharBuffer(size_t len) : wxCharTypeBufferBase(len) {}
wxWCharBuffer(const wxCStrData& cstr);
};
#endif // wxUSE_WCHAR_T
// wxCharTypeBuffer<T> implicitly convertible to T*
template <typename T>
class wxWritableCharTypeBuffer : public wxCharTypeBuffer<T>
{
public:
typedef typename wxCharTypeBuffer<T>::CharType CharType;
wxWritableCharTypeBuffer(const wxCharTypeBuffer<T>& src)
: wxCharTypeBuffer<T>(src) {}
// FIXME-UTF8: this won't be needed after converting mb_str()/wc_str() to
// always return a buffer
wxWritableCharTypeBuffer(const CharType *str = NULL)
: wxCharTypeBuffer<T>(str) {}
operator CharType*() { return this->data(); }
};
typedef wxWritableCharTypeBuffer<char> wxWritableCharBuffer;
typedef wxWritableCharTypeBuffer<wchar_t> wxWritableWCharBuffer;
#if wxUSE_UNICODE
#define wxWxCharBuffer wxWCharBuffer
#define wxMB2WXbuf wxWCharBuffer
#define wxWX2MBbuf wxCharBuffer
#if wxUSE_UNICODE_WCHAR
#define wxWC2WXbuf wxChar*
#define wxWX2WCbuf wxChar*
#elif wxUSE_UNICODE_UTF8
#define wxWC2WXbuf wxWCharBuffer
#define wxWX2WCbuf wxWCharBuffer
#endif
#else // ANSI
#define wxWxCharBuffer wxCharBuffer
#define wxMB2WXbuf wxChar*
#define wxWX2MBbuf wxChar*
#define wxWC2WXbuf wxCharBuffer
#define wxWX2WCbuf wxWCharBuffer
#endif // Unicode/ANSI
// type of the value returned by wxString::utf8_str()
#if wxUSE_UNICODE_UTF8
#define wxUTF8Buf char *
#else
#define wxUTF8Buf wxCharBuffer
#endif
// ----------------------------------------------------------------------------
// A class for holding growable data buffers (not necessarily strings)
// ----------------------------------------------------------------------------
// This class manages the actual data buffer pointer and is ref-counted.
class wxMemoryBufferData
{
public:
// the initial size and also the size added by ResizeIfNeeded()
enum { DefBufSize = 1024 };
friend class wxMemoryBuffer;
// everyting is private as it can only be used by wxMemoryBuffer
private:
wxMemoryBufferData(size_t size = wxMemoryBufferData::DefBufSize)
: m_data(size ? malloc(size) : NULL), m_size(size), m_len(0), m_ref(0)
{
}
~wxMemoryBufferData() { free(m_data); }
void ResizeIfNeeded(size_t newSize)
{
if (newSize > m_size)
{
void *dataOld = m_data;
m_data = realloc(m_data, newSize + wxMemoryBufferData::DefBufSize);
if ( !m_data )
{
free(dataOld);
}
m_size = newSize + wxMemoryBufferData::DefBufSize;
}
}
void IncRef() { m_ref += 1; }
void DecRef()
{
m_ref -= 1;
if (m_ref == 0) // are there no more references?
delete this;
}
// the buffer containing the data
void *m_data;
// the size of the buffer
size_t m_size;
// the amount of data currently in the buffer
size_t m_len;
// the reference count
size_t m_ref;
DECLARE_NO_COPY_CLASS(wxMemoryBufferData)
};
class wxMemoryBuffer
{
public:
// ctor and dtor
wxMemoryBuffer(size_t size = wxMemoryBufferData::DefBufSize)
{
m_bufdata = new wxMemoryBufferData(size);
m_bufdata->IncRef();
}
~wxMemoryBuffer() { m_bufdata->DecRef(); }
// copy and assignment
wxMemoryBuffer(const wxMemoryBuffer& src)
: m_bufdata(src.m_bufdata)
{
m_bufdata->IncRef();
}
wxMemoryBuffer& operator=(const wxMemoryBuffer& src)
{
if (&src != this)
{
m_bufdata->DecRef();
m_bufdata = src.m_bufdata;
m_bufdata->IncRef();
}
return *this;
}
// Accessors
void *GetData() const { return m_bufdata->m_data; }
size_t GetBufSize() const { return m_bufdata->m_size; }
size_t GetDataLen() const { return m_bufdata->m_len; }
void SetBufSize(size_t size) { m_bufdata->ResizeIfNeeded(size); }
void SetDataLen(size_t len)
{
wxASSERT(len <= m_bufdata->m_size);
m_bufdata->m_len = len;
}
// Ensure the buffer is big enough and return a pointer to it
void *GetWriteBuf(size_t sizeNeeded)
{
m_bufdata->ResizeIfNeeded(sizeNeeded);
return m_bufdata->m_data;
}
// Update the length after the write
void UngetWriteBuf(size_t sizeUsed) { SetDataLen(sizeUsed); }
// Like the above, but appends to the buffer
void *GetAppendBuf(size_t sizeNeeded)
{
m_bufdata->ResizeIfNeeded(m_bufdata->m_len + sizeNeeded);
return (char*)m_bufdata->m_data + m_bufdata->m_len;
}
// Update the length after the append
void UngetAppendBuf(size_t sizeUsed)
{
SetDataLen(m_bufdata->m_len + sizeUsed);
}
// Other ways to append to the buffer
void AppendByte(char data)
{
wxCHECK_RET( m_bufdata->m_data, _T("invalid wxMemoryBuffer") );
m_bufdata->ResizeIfNeeded(m_bufdata->m_len + 1);
*(((char*)m_bufdata->m_data) + m_bufdata->m_len) = data;
m_bufdata->m_len += 1;
}
void AppendData(const void *data, size_t len)
{
memcpy(GetAppendBuf(len), data, len);
UngetAppendBuf(len);
}
operator const char *() const { return (const char*)GetData(); }
private:
wxMemoryBufferData* m_bufdata;
};
// ----------------------------------------------------------------------------
// template class for any kind of data
// ----------------------------------------------------------------------------
// TODO
#endif // _WX_BUFFER_H