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[wxWidgets.git] / include / wx / buffer.h
1 ///////////////////////////////////////////////////////////////////////////////
2 // Name: wx/buffer.h
3 // Purpose: auto buffer classes: buffers which automatically free memory
4 // Author: Vadim Zeitlin
5 // Modified by:
6 // Created: 12.04.99
7 // RCS-ID: $Id$
8 // Copyright: (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
9 // Licence: wxWindows licence
10 ///////////////////////////////////////////////////////////////////////////////
11
12 #ifndef _WX_BUFFER_H
13 #define _WX_BUFFER_H
14
15 #include "wx/wxchar.h"
16
17 #include <stdlib.h> // malloc() and free()
18
19 // ----------------------------------------------------------------------------
20 // Special classes for (wide) character strings: they use malloc/free instead
21 // of new/delete
22 // ----------------------------------------------------------------------------
23
24 #define DEFINE_BUFFER(classname, chartype, strdupfunc) \
25 class WXDLLIMPEXP_BASE classname \
26 { \
27 public: \
28 classname(const chartype *str = NULL) \
29 : m_str(str ? strdupfunc(str) : NULL) \
30 { \
31 } \
32 \
33 classname(size_t len) \
34 : m_str((chartype *)malloc((len + 1)*sizeof(chartype))) \
35 { \
36 m_str[len] = (chartype)0; \
37 } \
38 \
39 /* no need to check for NULL, free() does it */ \
40 ~classname() { free(m_str); } \
41 \
42 /* \
43 WARNING: \
44 \
45 the copy ctor and assignment operators change the passed in object \
46 even although it is declared as "const", so: \
47 \
48 a) it shouldn't be really const \
49 b) you shouldn't use it afterwards (or know that it was reset) \
50 \
51 This is very ugly but is unfortunately needed to make the normal use\
52 of classname buffer objects possible and is very similar to what \
53 std::auto_ptr<> does (as if it were an excuse...) \
54 */ \
55 \
56 /* \
57 because of the remark above, release() is declared const even if it \
58 isn't really const \
59 */ \
60 chartype *release() const \
61 { \
62 chartype *p = m_str; \
63 ((classname *)this)->m_str = NULL; \
64 return p; \
65 } \
66 \
67 void reset() \
68 { \
69 free(m_str); \
70 m_str = NULL; \
71 } \
72 \
73 classname(const classname& src) \
74 : m_str(src.release()) \
75 { \
76 } \
77 \
78 classname& operator=(const chartype *str) \
79 { \
80 free(m_str); \
81 m_str = str ? strdupfunc(str) : NULL; \
82 return *this; \
83 } \
84 \
85 classname& operator=(const classname& src) \
86 { \
87 free(m_str); \
88 m_str = src.release(); \
89 \
90 return *this; \
91 } \
92 \
93 bool extend(size_t len) \
94 { \
95 chartype * \
96 str = (chartype *)realloc(m_str, (len + 1)*sizeof(chartype)); \
97 if ( !str ) \
98 return false; \
99 \
100 m_str = str; \
101 \
102 return true; \
103 } \
104 \
105 chartype *data() { return m_str; } \
106 const chartype *data() const { return m_str; } \
107 operator const chartype *() const { return m_str; } \
108 chartype operator[](size_t n) const { return m_str[n]; } \
109 \
110 private: \
111 chartype *m_str; \
112 }
113
114 DEFINE_BUFFER(wxCharBuffer, char, wxStrdupA);
115
116 #if wxUSE_WCHAR_T
117
118 DEFINE_BUFFER(wxWCharBuffer, wchar_t, wxStrdupW);
119
120 #endif // wxUSE_WCHAR_T
121
122 #undef DEFINE_BUFFER
123
124 #if wxUSE_UNICODE
125 typedef wxWCharBuffer wxWxCharBuffer;
126
127 #define wxMB2WXbuf wxWCharBuffer
128 #define wxWX2MBbuf wxCharBuffer
129 #define wxWC2WXbuf wxChar*
130 #define wxWX2WCbuf wxChar*
131 #else // ANSI
132 typedef wxCharBuffer wxWxCharBuffer;
133
134 #define wxMB2WXbuf wxChar*
135 #define wxWX2MBbuf wxChar*
136 #define wxWC2WXbuf wxCharBuffer
137 #define wxWX2WCbuf wxWCharBuffer
138 #endif // Unicode/ANSI
139
140 // ----------------------------------------------------------------------------
141 // A class for holding growable data buffers (not necessarily strings)
142 // ----------------------------------------------------------------------------
143
144 // This class manages the actual data buffer pointer and is ref-counted.
145 class wxMemoryBufferData
146 {
147 public:
148 // the initial size and also the size added by ResizeIfNeeded()
149 enum { DefBufSize = 1024 };
150
151 friend class wxMemoryBuffer;
152
153 // everyting is private as it can only be used by wxMemoryBuffer
154 private:
155 wxMemoryBufferData(size_t size = wxMemoryBufferData::DefBufSize)
156 : m_data(size ? malloc(size) : NULL), m_size(size), m_len(0), m_ref(0)
157 {
158 }
159 ~wxMemoryBufferData() { free(m_data); }
160
161
162 void ResizeIfNeeded(size_t newSize)
163 {
164 if (newSize > m_size)
165 {
166 void *dataOld = m_data;
167 m_data = realloc(m_data, newSize + wxMemoryBufferData::DefBufSize);
168 if ( !m_data )
169 {
170 free(dataOld);
171 }
172
173 m_size = newSize + wxMemoryBufferData::DefBufSize;
174 }
175 }
176
177 void IncRef() { m_ref += 1; }
178 void DecRef()
179 {
180 m_ref -= 1;
181 if (m_ref == 0) // are there no more references?
182 delete this;
183 }
184
185
186 // the buffer containing the data
187 void *m_data;
188
189 // the size of the buffer
190 size_t m_size;
191
192 // the amount of data currently in the buffer
193 size_t m_len;
194
195 // the reference count
196 size_t m_ref;
197
198 DECLARE_NO_COPY_CLASS(wxMemoryBufferData)
199 };
200
201
202 class wxMemoryBuffer
203 {
204 public:
205 // ctor and dtor
206 wxMemoryBuffer(size_t size = wxMemoryBufferData::DefBufSize)
207 {
208 m_bufdata = new wxMemoryBufferData(size);
209 m_bufdata->IncRef();
210 }
211
212 ~wxMemoryBuffer() { m_bufdata->DecRef(); }
213
214
215 // copy and assignment
216 wxMemoryBuffer(const wxMemoryBuffer& src)
217 : m_bufdata(src.m_bufdata)
218 {
219 m_bufdata->IncRef();
220 }
221
222 wxMemoryBuffer& operator=(const wxMemoryBuffer& src)
223 {
224 m_bufdata->DecRef();
225 m_bufdata = src.m_bufdata;
226 m_bufdata->IncRef();
227 return *this;
228 }
229
230
231 // Accessors
232 void *GetData() const { return m_bufdata->m_data; }
233 size_t GetBufSize() const { return m_bufdata->m_size; }
234 size_t GetDataLen() const { return m_bufdata->m_len; }
235
236 void SetBufSize(size_t size) { m_bufdata->ResizeIfNeeded(size); }
237 void SetDataLen(size_t len)
238 {
239 wxASSERT(len <= m_bufdata->m_size);
240 m_bufdata->m_len = len;
241 }
242
243 // Ensure the buffer is big enough and return a pointer to it
244 void *GetWriteBuf(size_t sizeNeeded)
245 {
246 m_bufdata->ResizeIfNeeded(sizeNeeded);
247 return m_bufdata->m_data;
248 }
249
250 // Update the length after the write
251 void UngetWriteBuf(size_t sizeUsed) { SetDataLen(sizeUsed); }
252
253 // Like the above, but appends to the buffer
254 void *GetAppendBuf(size_t sizeNeeded)
255 {
256 m_bufdata->ResizeIfNeeded(m_bufdata->m_len + sizeNeeded);
257 return (char*)m_bufdata->m_data + m_bufdata->m_len;
258 }
259
260 // Update the length after the append
261 void UngetAppendBuf(size_t sizeUsed)
262 {
263 SetDataLen(m_bufdata->m_len + sizeUsed);
264 }
265
266 // Other ways to append to the buffer
267 void AppendByte(char data)
268 {
269 wxCHECK_RET( m_bufdata->m_data, _T("invalid wxMemoryBuffer") );
270
271 m_bufdata->ResizeIfNeeded(m_bufdata->m_len + 1);
272 *(((char*)m_bufdata->m_data) + m_bufdata->m_len) = data;
273 m_bufdata->m_len += 1;
274 }
275
276 void AppendData(const void *data, size_t len)
277 {
278 memcpy(GetAppendBuf(len), data, len);
279 UngetAppendBuf(len);
280 }
281
282 operator const char *() const { return (const char*)GetData(); }
283
284 private:
285 wxMemoryBufferData* m_bufdata;
286 };
287
288 // ----------------------------------------------------------------------------
289 // template class for any kind of data
290 // ----------------------------------------------------------------------------
291
292 // TODO
293
294 #endif // _WX_BUFFER_H
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