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/wxchar.h"
#include <stdlib.h> // malloc() and free()
// ----------------------------------------------------------------------------
// Special classes for (wide) character strings: they use malloc/free instead
// of new/delete
// ----------------------------------------------------------------------------
#define DEFINE_BUFFER(classname, chartype, strdupfunc) \
class WXDLLIMPEXP_BASE classname \
{ \
public: \
classname(const chartype *str) \
: m_str(str ? strdupfunc(str) : NULL) \
{ \
} \
\
classname(size_t len) \
: m_str((chartype *)malloc((len + 1)*sizeof(chartype))) \
{ \
m_str[len] = (chartype)0; \
} \
\
/* no need to check for NULL, free() does it */ \
~classname() { free(m_str); } \
\
/* \
WARNING: \
\
the copy ctor and assignment operators change the passed in object \
even although it is declared as "const", so: \
\
a) it shouldn't be really const \
b) you shouldn't use it afterwards (or know that it was reset) \
\
This is very ugly but is unfortunately needed to make the normal use\
of classname buffer objects possible and is very similar to what \
std::auto_ptr<> does (as if it were an excuse...) \
*/ \
\
/* \
because of the remark above, release() is declared const even if it \
isn't really const \
*/ \
chartype *release() const \
{ \
chartype *p = m_str; \
((classname *)this)->m_str = NULL; \
return p; \
} \
\
classname(const classname& src) \
: m_str(src.release()) \
{ \
} \
\
classname& operator=(const chartype *str) \
{ \
free(m_str); \
m_str = str ? strdupfunc(str) : NULL; \
return *this; \
} \
\
classname& operator=(const classname& src) \
{ \
free(m_str); \
m_str = src.release(); \
\
return *this; \
} \
\
chartype *data() { return m_str; } \
const chartype *data() const { return m_str; } \
operator const chartype *() const { return m_str; } \
chartype operator[](size_t n) const { return m_str[n]; } \
\
private: \
chartype *m_str; \
}
DEFINE_BUFFER(wxCharBuffer, char, wxStrdupA);
#if wxUSE_WCHAR_T
DEFINE_BUFFER(wxWCharBuffer, wchar_t, wxStrdupW);
#endif // wxUSE_WCHAR_T
#undef DEFINE_BUFFER
#if wxUSE_UNICODE
#define wxMB2WXbuf wxWCharBuffer
#define wxWX2MBbuf wxCharBuffer
#define wxWC2WXbuf wxChar*
#define wxWX2WCbuf wxChar*
#else // ANSI
#define wxMB2WXbuf wxChar*
#define wxWX2MBbuf wxChar*
#define wxWC2WXbuf wxCharBuffer
#define wxWX2WCbuf wxWCharBuffer
#endif // Unicode/ANSI
// ----------------------------------------------------------------------------
// 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 { BLOCK_SIZE = 1024 };
friend class wxMemoryBuffer;
// everyting is private as it can only be used by wxMemoryBuffer
private:
wxMemoryBufferData(size_t size = wxMemoryBufferData::BLOCK_SIZE)
: 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::BLOCK_SIZE);
if ( !m_data )
{
free(dataOld);
}
m_size = newSize + wxMemoryBufferData::BLOCK_SIZE;
}
}
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::BLOCK_SIZE)
{
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)
{
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(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