]>
Commit | Line | Data |
---|---|---|
f8f6c91a MW |
1 | ///////////////////////////////////////////////////////////////////////////// |
2 | // Name: src/common/fileback.cpp | |
3 | // Purpose: Back an input stream with memory or a file | |
4 | // Author: Mike Wetherell | |
5 | // RCS-ID: $Id$ | |
6 | // Copyright: (c) 2006 Mike Wetherell | |
7 | // Licence: wxWindows licence | |
8 | ///////////////////////////////////////////////////////////////////////////// | |
9 | ||
10 | // For compilers that support precompilation, includes "wx.h". | |
11 | #include "wx/wxprec.h" | |
12 | ||
13 | #ifdef __BORLANDC__ | |
14 | #pragma hdrstop | |
15 | #endif | |
16 | ||
17 | #if wxUSE_BACKINGFILE | |
18 | ||
360c6a85 PC |
19 | #include "wx/fileback.h" |
20 | ||
f8f6c91a | 21 | #ifndef WX_PRECOMP |
f8f6c91a MW |
22 | #include "wx/utils.h" |
23 | #include "wx/log.h" | |
24 | #endif | |
25 | ||
f8f6c91a MW |
26 | #include "wx/private/filename.h" |
27 | ||
28 | // Prefer wxFFile unless wxFile has large file support but wxFFile does not. | |
29 | // | |
82b99cf9 | 30 | #if wxUSE_FFILE && (defined wxHAS_LARGE_FFILES || !defined wxHAS_LARGE_FILES) |
f8f6c91a MW |
31 | typedef wxFFile wxBFFile; |
32 | static const bool wxBadSeek = false; | |
33 | #else | |
34 | typedef wxFile wxBFFile; | |
35 | static const wxFileOffset wxBadSeek = wxInvalidOffset; | |
36 | #endif | |
37 | ||
38 | ///////////////////////////////////////////////////////////////////////////// | |
39 | // Backing file implementation | |
40 | ||
41 | class wxBackingFileImpl | |
42 | { | |
43 | public: | |
44 | wxBackingFileImpl(wxInputStream *stream, | |
45 | size_t bufsize, | |
46 | const wxString& prefix); | |
47 | ~wxBackingFileImpl(); | |
48 | ||
49 | void Release() { if (--m_refcount == 0) delete this; } | |
50 | wxBackingFileImpl *AddRef() { m_refcount++; return this; } | |
51 | ||
52 | wxStreamError ReadAt(wxFileOffset pos, void *buffer, size_t *size); | |
53 | wxFileOffset GetLength() const; | |
54 | ||
55 | private: | |
56 | int m_refcount; | |
57 | ||
58 | wxInputStream *m_stream; | |
59 | wxStreamError m_parenterror; | |
60 | ||
61 | char *m_buf; | |
62 | size_t m_bufsize; | |
63 | size_t m_buflen; | |
64 | ||
65 | wxString m_prefix; | |
66 | wxString m_filename; | |
67 | wxBFFile m_file; | |
68 | wxFileOffset m_filelen; | |
69 | }; | |
70 | ||
71 | wxBackingFileImpl::wxBackingFileImpl(wxInputStream *stream, | |
72 | size_t bufsize, | |
73 | const wxString& prefix) | |
74 | : m_refcount(1), | |
75 | m_stream(stream), | |
76 | m_parenterror(wxSTREAM_NO_ERROR), | |
77 | m_buf(NULL), | |
78 | m_bufsize(bufsize), | |
79 | m_buflen(0), | |
80 | m_prefix(prefix), | |
81 | m_filelen(0) | |
82 | { | |
83 | wxFileOffset len = m_stream->GetLength(); | |
84 | ||
12811c1c | 85 | if (len >= 0 && len + size_t(1) < m_bufsize) |
8aa3cd14 | 86 | m_bufsize = size_t(len + 1); |
f8f6c91a MW |
87 | |
88 | if (m_bufsize) | |
89 | m_buf = new char[m_bufsize]; | |
90 | } | |
91 | ||
92 | wxBackingFileImpl::~wxBackingFileImpl() | |
93 | { | |
94 | delete m_stream; | |
95 | delete [] m_buf; | |
96 | ||
97 | if (!m_filename.empty()) | |
98 | wxRemoveFile(m_filename); | |
99 | } | |
100 | ||
101 | wxStreamError wxBackingFileImpl::ReadAt(wxFileOffset pos, | |
102 | void *buffer, | |
103 | size_t *size) | |
104 | { | |
105 | size_t reqestedSize = *size; | |
106 | *size = 0; | |
107 | ||
108 | // size1 is the number of bytes it will read directly from the backing | |
109 | // file. size2 is any remaining bytes not yet backed, these are returned | |
110 | // from the buffer or read from the parent stream. | |
111 | size_t size1, size2; | |
112 | ||
113 | if (pos + reqestedSize <= m_filelen + size_t(0)) { | |
114 | size1 = reqestedSize; | |
115 | size2 = 0; | |
116 | } else if (pos < m_filelen) { | |
4ee9daf4 | 117 | size1 = size_t(m_filelen - pos); |
f8f6c91a MW |
118 | size2 = reqestedSize - size1; |
119 | } else { | |
120 | size1 = 0; | |
121 | size2 = reqestedSize; | |
122 | } | |
123 | ||
124 | if (pos < 0) | |
125 | return wxSTREAM_READ_ERROR; | |
126 | ||
127 | // read the backing file | |
128 | if (size1) { | |
129 | if (m_file.Seek(pos) == wxBadSeek) | |
130 | return wxSTREAM_READ_ERROR; | |
131 | ||
132 | ssize_t n = m_file.Read(buffer, size1); | |
133 | if (n > 0) { | |
134 | *size = n; | |
135 | pos += n; | |
136 | } | |
137 | ||
138 | if (*size < size1) | |
139 | return wxSTREAM_READ_ERROR; | |
140 | } | |
141 | ||
142 | // read from the buffer or parent stream | |
143 | if (size2) | |
144 | { | |
145 | while (*size < reqestedSize) | |
146 | { | |
147 | // if pos is further ahead than the parent has been read so far, | |
148 | // then read forward in the parent stream | |
149 | while (pos - m_filelen + size_t(0) >= m_buflen) | |
150 | { | |
151 | // if the parent is small enough, don't use a backing file | |
152 | // just the buffer memory | |
153 | if (!m_stream && m_filelen == 0) | |
154 | return m_parenterror; | |
155 | ||
156 | // before refilling the buffer write out the current buffer | |
157 | // to the backing file if there is anything in it | |
158 | if (m_buflen) | |
159 | { | |
160 | if (!m_file.IsOpened()) | |
161 | if (!wxCreateTempFile(m_prefix, &m_file, &m_filename)) | |
162 | return wxSTREAM_READ_ERROR; | |
163 | ||
164 | if (m_file.Seek(m_filelen) == wxBadSeek) | |
165 | return wxSTREAM_READ_ERROR; | |
166 | ||
167 | size_t count = m_file.Write(m_buf, m_buflen); | |
168 | m_filelen += count; | |
169 | ||
170 | if (count < m_buflen) { | |
171 | delete m_stream; | |
172 | m_stream = NULL; | |
173 | if (count > 0) { | |
e7c6f5a1 | 174 | delete[] m_buf; |
f8f6c91a MW |
175 | m_buf = NULL; |
176 | m_buflen = 0; | |
177 | } | |
178 | m_parenterror = wxSTREAM_READ_ERROR; | |
179 | return m_parenterror; | |
180 | } | |
181 | ||
182 | m_buflen = 0; | |
183 | ||
184 | if (!m_stream) { | |
e7c6f5a1 | 185 | delete[] m_buf; |
f8f6c91a MW |
186 | m_buf = NULL; |
187 | } | |
188 | } | |
189 | ||
190 | if (!m_stream) | |
191 | return m_parenterror; | |
192 | ||
193 | // refill buffer | |
194 | m_buflen = m_stream->Read(m_buf, m_bufsize).LastRead(); | |
195 | ||
196 | if (m_buflen < m_bufsize) { | |
197 | m_parenterror = m_stream->GetLastError(); | |
198 | if (m_parenterror == wxSTREAM_NO_ERROR) | |
199 | m_parenterror = wxSTREAM_EOF; | |
200 | delete m_stream; | |
201 | m_stream = NULL; | |
202 | } | |
203 | } | |
204 | ||
205 | // copy to the user's buffer | |
4ee9daf4 | 206 | size_t start = size_t(pos - m_filelen); |
f8f6c91a MW |
207 | size_t len = wxMin(m_buflen - start, reqestedSize - *size); |
208 | ||
209 | memcpy((char*)buffer + *size, m_buf + start, len); | |
210 | *size += len; | |
211 | pos += len; | |
212 | } | |
213 | } | |
214 | ||
215 | return wxSTREAM_NO_ERROR; | |
216 | } | |
217 | ||
218 | wxFileOffset wxBackingFileImpl::GetLength() const | |
219 | { | |
220 | if (m_parenterror != wxSTREAM_EOF) { | |
221 | wxLogNull nolog; | |
222 | return m_stream->GetLength(); | |
223 | } | |
224 | return m_filelen + m_buflen; | |
225 | } | |
226 | ||
227 | ||
228 | ///////////////////////////////////////////////////////////////////////////// | |
229 | // Backing File, the handle part | |
230 | ||
231 | wxBackingFile::wxBackingFile(wxInputStream *stream, | |
232 | size_t bufsize, | |
233 | const wxString& prefix) | |
234 | : m_impl(new wxBackingFileImpl(stream, bufsize, prefix)) | |
235 | { | |
236 | } | |
237 | ||
238 | wxBackingFile::wxBackingFile(const wxBackingFile& backer) | |
239 | : m_impl(backer.m_impl ? backer.m_impl->AddRef() : NULL) | |
240 | { | |
241 | } | |
242 | ||
243 | wxBackingFile& wxBackingFile::operator=(const wxBackingFile& backer) | |
244 | { | |
245 | if (backer.m_impl != m_impl) { | |
246 | if (m_impl) | |
247 | m_impl->Release(); | |
248 | ||
249 | m_impl = backer.m_impl; | |
250 | ||
251 | if (m_impl) | |
252 | m_impl->AddRef(); | |
253 | } | |
254 | ||
255 | return *this; | |
256 | } | |
257 | ||
258 | wxBackingFile::~wxBackingFile() | |
259 | { | |
260 | if (m_impl) | |
261 | m_impl->Release(); | |
262 | } | |
263 | ||
264 | ||
265 | ///////////////////////////////////////////////////////////////////////////// | |
266 | // Input stream | |
267 | ||
268 | wxBackedInputStream::wxBackedInputStream(const wxBackingFile& backer) | |
269 | : m_backer(backer), | |
270 | m_pos(0) | |
271 | { | |
272 | } | |
273 | ||
1ab48408 MW |
274 | wxFileOffset wxBackedInputStream::GetLength() const |
275 | { | |
276 | return m_backer.m_impl->GetLength(); | |
277 | } | |
278 | ||
279 | wxFileOffset wxBackedInputStream::FindLength() const | |
280 | { | |
281 | wxFileOffset len = GetLength(); | |
282 | ||
283 | if (len == wxInvalidOffset && IsOk()) { | |
284 | // read a byte at 7ff...ffe | |
285 | wxFileOffset pos = 1; | |
286 | pos <<= sizeof(pos) * 8 - 1; | |
287 | pos = ~pos - 1; | |
288 | char ch; | |
289 | size_t size = 1; | |
290 | m_backer.m_impl->ReadAt(pos, &ch, &size); | |
291 | len = GetLength(); | |
292 | } | |
293 | ||
294 | return len; | |
295 | } | |
296 | ||
f8f6c91a MW |
297 | size_t wxBackedInputStream::OnSysRead(void *buffer, size_t size) |
298 | { | |
299 | if (!IsOk()) | |
300 | return 0; | |
301 | ||
302 | m_lasterror = m_backer.m_impl->ReadAt(m_pos, buffer, &size); | |
303 | m_pos += size; | |
304 | return size; | |
305 | } | |
306 | ||
f8f6c91a MW |
307 | wxFileOffset wxBackedInputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode) |
308 | { | |
309 | switch (mode) { | |
310 | case wxFromCurrent: | |
311 | { | |
312 | m_pos += pos; | |
313 | break; | |
314 | } | |
315 | case wxFromEnd: | |
316 | { | |
317 | wxFileOffset len = GetLength(); | |
318 | if (len == wxInvalidOffset) | |
319 | return wxInvalidOffset; | |
320 | m_pos = len + pos; | |
321 | break; | |
322 | } | |
323 | default: | |
324 | { | |
325 | m_pos = pos; | |
326 | break; | |
327 | } | |
328 | } | |
329 | ||
330 | return m_pos; | |
331 | } | |
332 | ||
333 | wxFileOffset wxBackedInputStream::OnSysTell() const | |
334 | { | |
335 | return m_pos; | |
336 | } | |
337 | ||
338 | #endif // wxUSE_BACKINGFILE |