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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) \
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 classname(const classname& src) \
68 : m_str(src.release()) \
69 { \
70 } \
71 \
72 classname& operator=(const chartype *str) \
73 { \
74 free(m_str); \
75 m_str = str ? strdupfunc(str) : NULL; \
76 return *this; \
77 } \
78 \
79 classname& operator=(const classname& src) \
80 { \
81 free(m_str); \
82 m_str = src.release(); \
83 \
84 return *this; \
85 } \
86 \
87 chartype *data() { return m_str; } \
88 const chartype *data() const { return m_str; } \
89 operator const chartype *() const { return m_str; } \
90 chartype operator[](size_t n) const { return m_str[n]; } \
91 \
92 private: \
93 chartype *m_str; \
94 }
95
96 DEFINE_BUFFER(wxCharBuffer, char, wxStrdupA);
97
98 #if wxUSE_WCHAR_T
99
100 DEFINE_BUFFER(wxWCharBuffer, wchar_t, wxStrdupW);
101
102 #endif // wxUSE_WCHAR_T
103
104 #undef DEFINE_BUFFER
105
106 #if wxUSE_UNICODE
107 #define wxMB2WXbuf wxWCharBuffer
108 #define wxWX2MBbuf wxCharBuffer
109 #define wxWC2WXbuf wxChar*
110 #define wxWX2WCbuf wxChar*
111 #else // ANSI
112 #define wxMB2WXbuf wxChar*
113 #define wxWX2MBbuf wxChar*
114 #define wxWC2WXbuf wxCharBuffer
115 #define wxWX2WCbuf wxWCharBuffer
116 #endif // Unicode/ANSI
117
118 // ----------------------------------------------------------------------------
119 // A class for holding growable data buffers (not necessarily strings)
120 // ----------------------------------------------------------------------------
121
122 // This class manages the actual data buffer pointer and is ref-counted.
123 class wxMemoryBufferData
124 {
125 public:
126 // the initial size and also the size added by ResizeIfNeeded()
127 enum { BLOCK_SIZE = 1024 };
128
129 friend class wxMemoryBuffer;
130
131 // everyting is private as it can only be used by wxMemoryBuffer
132 private:
133 wxMemoryBufferData(size_t size = wxMemoryBufferData::BLOCK_SIZE)
134 : m_data(size ? malloc(size) : NULL), m_size(size), m_len(0), m_ref(0)
135 {
136 }
137 ~wxMemoryBufferData() { free(m_data); }
138
139
140 void ResizeIfNeeded(size_t newSize)
141 {
142 if (newSize > m_size)
143 {
144 void *dataOld = m_data;
145 m_data = realloc(m_data, newSize + wxMemoryBufferData::BLOCK_SIZE);
146 if ( !m_data )
147 {
148 free(dataOld);
149 }
150
151 m_size = newSize + wxMemoryBufferData::BLOCK_SIZE;
152 }
153 }
154
155 void IncRef() { m_ref += 1; }
156 void DecRef()
157 {
158 m_ref -= 1;
159 if (m_ref == 0) // are there no more references?
160 delete this;
161 }
162
163
164 // the buffer containing the data
165 void *m_data;
166
167 // the size of the buffer
168 size_t m_size;
169
170 // the amount of data currently in the buffer
171 size_t m_len;
172
173 // the reference count
174 size_t m_ref;
175
176 DECLARE_NO_COPY_CLASS(wxMemoryBufferData)
177 };
178
179
180 class wxMemoryBuffer
181 {
182 public:
183 // ctor and dtor
184 wxMemoryBuffer(size_t size = wxMemoryBufferData::BLOCK_SIZE)
185 {
186 m_bufdata = new wxMemoryBufferData(size);
187 m_bufdata->IncRef();
188 }
189
190 ~wxMemoryBuffer() { m_bufdata->DecRef(); }
191
192
193 // copy and assignment
194 wxMemoryBuffer(const wxMemoryBuffer& src)
195 : m_bufdata(src.m_bufdata)
196 {
197 m_bufdata->IncRef();
198 }
199
200 wxMemoryBuffer& operator=(const wxMemoryBuffer& src)
201 {
202 m_bufdata->DecRef();
203 m_bufdata = src.m_bufdata;
204 m_bufdata->IncRef();
205 return *this;
206 }
207
208
209 // Accessors
210 void *GetData() const { return m_bufdata->m_data; }
211 size_t GetBufSize() const { return m_bufdata->m_size; }
212 size_t GetDataLen() const { return m_bufdata->m_len; }
213
214 void SetBufSize(size_t size) { m_bufdata->ResizeIfNeeded(size); }
215 void SetDataLen(size_t len)
216 {
217 wxASSERT(len <= m_bufdata->m_size);
218 m_bufdata->m_len = len;
219 }
220
221 // Ensure the buffer is big enough and return a pointer to it
222 void *GetWriteBuf(size_t sizeNeeded)
223 {
224 m_bufdata->ResizeIfNeeded(sizeNeeded);
225 return m_bufdata->m_data;
226 }
227
228 // Update the length after the write
229 void UngetWriteBuf(size_t sizeUsed) { SetDataLen(sizeUsed); }
230
231 // Like the above, but appends to the buffer
232 void *GetAppendBuf(size_t sizeNeeded)
233 {
234 m_bufdata->ResizeIfNeeded(m_bufdata->m_len + sizeNeeded);
235 return (char*)m_bufdata->m_data + m_bufdata->m_len;
236 }
237
238 // Update the length after the append
239 void UngetAppendBuf(size_t sizeUsed)
240 {
241 SetDataLen(m_bufdata->m_len + sizeUsed);
242 }
243
244 // Other ways to append to the buffer
245 void AppendByte(char data)
246 {
247 wxCHECK_RET( m_bufdata->m_data, _T("invalid wxMemoryBuffer") );
248
249 m_bufdata->ResizeIfNeeded(m_bufdata->m_len + 1);
250 *(((char*)m_bufdata->m_data) + m_bufdata->m_len) = data;
251 m_bufdata->m_len += 1;
252 }
253
254 void AppendData(void* data, size_t len)
255 {
256 memcpy(GetAppendBuf(len), data, len);
257 UngetAppendBuf(len);
258 }
259
260 operator const char *() const { return (const char*)GetData(); }
261
262 private:
263 wxMemoryBufferData* m_bufdata;
264 };
265
266 // ----------------------------------------------------------------------------
267 // template class for any kind of data
268 // ----------------------------------------------------------------------------
269
270 // TODO
271
272 #endif // _WX_BUFFER_H
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