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Root/branches/xZenu/src/util/doxygen/src/store.cpp

Source at commit 1322 created 12 years 8 months ago.
By meklort, Add doxygen to utils folder
1/******************************************************************************␊
2 *␊
3 * $Id:$␊
4 *␊
5 *␊
6 * Copyright (C) 1997-2011 by Dimitri van Heesch.␊
7 *␊
8 * Permission to use, copy, modify, and distribute this software and its␊
9 * documentation under the terms of the GNU General Public License is hereby ␊
10 * granted. No representations are made about the suitability of this software ␊
11 * for any purpose. It is provided "as is" without express or implied warranty.␊
12 * See the GNU General Public License for more details.␊
13 *␊
14 * Documents produced by Doxygen are derivative works derived from the␊
15 * input used in their production; they are not affected by this license.␊
16 *␊
17 */␊
18␊
19#include "store.h"␊
20#include "portable.h"␊
21␊
22␊
23#include <stdio.h>␊
24#include <stdlib.h>␊
25#include <errno.h>␊
26#include <string.h>␊
27#include <assert.h>␊
28␊
29#define BLOCK_SIZE 512 // should be >8 and a multiple of 8␊
30#define BLOCK_POINTER_SIZE sizeof(portable_off_t)␊
31␊
32␊
33#define ASSERTS_ENABLED␊
34␊
35#ifdef ASSERTS_ENABLED␊
36#define STORE_ASSERT(x) assert(x)␊
37#else␊
38#define STORE_ASSERT(x)␊
39#endif␊
40␊
41//------------------------------------------------------------------------------------␊
42␊
43Store::Store() ␊
44{␊
45 m_file = 0;␊
46 m_front = 0;␊
47 m_head = 0;␊
48 m_state = Init;␊
49 m_reads = 0;␊
50 m_writes = 0;␊
51}␊
52␊
53Store::~Store()␊
54{␊
55 if (m_file) fclose(m_file);␊
56␊
57 // clean up free list␊
58 while (m_head)␊
59 {␊
60 Node *node = m_head;␊
61 m_head = node->next;␊
62 delete node;␊
63 }␊
64}␊
65␊
66int Store::open(const char *name)␊
67{␊
68 int i;␊
69 STORE_ASSERT(m_state==Init);␊
70 if (m_file) return 0; // already open␊
71 m_file = portable_fopen(name,"w+b");␊
72 if (m_file==0) return -1;␊
73␊
74 // first block serves as header, so offset=0 can be used as the end of the list.␊
75 for (i=0;i<BLOCK_SIZE/8;i++)␊
76 {␊
77 fputc('D',m_file);␊
78 fputc('O',m_file);␊
79 fputc('X',m_file);␊
80 fputc('Y',m_file);␊
81 fputc('G',m_file);␊
82 fputc('E',m_file);␊
83 fputc('N',m_file);␊
84 fputc(0,m_file);␊
85 }␊
86 m_front = BLOCK_SIZE;␊
87 m_head = 0;␊
88 m_state = Reading;␊
89 return 0;␊
90}␊
91␊
92void Store::close()␊
93{␊
94 if (m_file) fclose(m_file);␊
95 m_file=0;␊
96 m_state = Init;␊
97}␊
98 ␊
99portable_off_t Store::alloc()␊
100{␊
101 STORE_ASSERT(m_state==Reading);␊
102 m_state=Writing;␊
103 portable_off_t pos;␊
104 if (m_head==0) // allocate new block␊
105 {␊
106 //printf("alloc: new block\n");␊
107 if (portable_fseek(m_file,0,SEEK_END)==-1) // go to end of the file␊
108 {␊
109 fprintf(stderr,"Store::alloc: Error seeking to end of file: %s\n",strerror(errno));␊
110 exit(1);␊
111 }␊
112 pos = portable_ftell(m_file);␊
113 STORE_ASSERT( (pos & (BLOCK_SIZE-1))==0 );␊
114 m_front = pos + BLOCK_SIZE; // move front to end of this block␊
115 }␊
116 else // reuse freed block␊
117 {␊
118 //printf("alloc: reuse block: m_head=%d\n",(int)m_head);␊
119 Node *node = m_head;␊
120 pos = node->pos;␊
121 // point head to next free item␊
122 m_head = node->next;␊
123 delete node;␊
124 // move to start of the block␊
125 if (portable_fseek(m_file,pos,SEEK_SET)==-1)␊
126 {␊
127 fprintf(stderr,"Store::alloc: Error seeking to position %d: %s\n",␊
128 (int)pos,strerror(errno));␊
129 exit(1);␊
130 }␊
131 STORE_ASSERT( (pos & (BLOCK_SIZE-1))==0 );␊
132 }␊
133 //printf("%x: Store::alloc\n",(int)pos);␊
134 return pos;␊
135}␊
136␊
137int Store::write(const char *buf,uint size)␊
138{␊
139 STORE_ASSERT(m_state==Writing);␊
140 //printf("%x: Store::write\n",(int)portable_ftell(m_file));␊
141 do␊
142 {␊
143 portable_off_t curPos = portable_ftell(m_file);␊
144 int bytesInBlock = BLOCK_SIZE - BLOCK_POINTER_SIZE - (curPos & (BLOCK_SIZE-1));␊
145 int bytesLeft = bytesInBlock<(int)size ? (int)size-bytesInBlock : 0;␊
146 int numBytes = size - bytesLeft;␊
147 STORE_ASSERT(bytesInBlock>=0);␊
148 STORE_ASSERT(numBytes<=(int)(BLOCK_SIZE-BLOCK_POINTER_SIZE));␊
149 if (numBytes>0)␊
150 {␊
151 if ((int)fwrite(buf,1,numBytes,m_file)!=numBytes)␊
152 {␊
153 fprintf(stderr,"Error writing: %s\n",strerror(errno));␊
154 exit(1);␊
155 }␊
156 m_writes++;␊
157 }␊
158 if (bytesLeft>0) // still more bytes to write␊
159 {␊
160 STORE_ASSERT(((portable_ftell(m_file)+BLOCK_POINTER_SIZE)&(BLOCK_SIZE-1))==0);␊
161 // allocate new block␊
162 if (m_head==0) // no free blocks to reuse␊
163 {␊
164 //printf("%x: Store::write: new: pos=%x\n",(int)m_front,(int)portable_ftell(m_file));␊
165 // write pointer to next block␊
166 if (fwrite(&m_front,BLOCK_POINTER_SIZE,1,m_file)!=1)␊
167 {␊
168 fprintf(stderr,"Error writing to store: %s\n",strerror(errno));␊
169 exit(1);␊
170 }␊
171 STORE_ASSERT(portable_ftell(m_file)==(curPos&~(BLOCK_SIZE-1))+BLOCK_SIZE);␊
172␊
173 // move to next block␊
174 if (portable_fseek(m_file,0,SEEK_END)==-1) // go to end of the file␊
175 {␊
176 fprintf(stderr,"Store::alloc: Error seeking to end of file: %s\n",strerror(errno));␊
177 exit(1);␊
178 }␊
179 STORE_ASSERT(portable_ftell(m_file)==m_front);␊
180 // move front to the next of the block␊
181 m_front+=BLOCK_SIZE;␊
182 }␊
183 else // reuse block from the free list␊
184 {␊
185 // write pointer to next block␊
186 if (fwrite(&m_head->pos,BLOCK_POINTER_SIZE,1,m_file)!=1)␊
187 {␊
188 fprintf(stderr,"Error writing to store: %s\n",strerror(errno));␊
189 exit(1);␊
190 }␊
191 Node *node = m_head;␊
192 portable_off_t pos = node->pos;␊
193 // point head to next free item␊
194 m_head = node->next;␊
195 delete node;␊
196 // move to start of the block␊
197 if (portable_fseek(m_file,pos,SEEK_SET)==-1)␊
198 {␊
199 fprintf(stderr,"Store::write: Error seeking to position %d: %s\n",␊
200 (int)pos,strerror(errno));␊
201 exit(1);␊
202 }␊
203 //printf("%x: Store::write: reuse\n",(int)pos);␊
204 }␊
205 }␊
206 size-=numBytes;␊
207 buf+=numBytes;␊
208 }␊
209 while (size>0);␊
210 return size;␊
211}␊
212␊
213void Store::end()␊
214{␊
215 STORE_ASSERT(m_state==Writing);␊
216 portable_off_t curPos = portable_ftell(m_file);␊
217 int bytesInBlock = BLOCK_SIZE - (curPos & (BLOCK_SIZE-1));␊
218 //printf("%x: Store::end erasing %x bytes\n",(int)curPos&~(BLOCK_SIZE-1),bytesInBlock);␊
219 //printf("end: bytesInBlock=%x\n",bytesInBlock);␊
220 // zero out rest of the block␊
221 int i;␊
222 for (i=0;i<bytesInBlock;i++)␊
223 {␊
224 fputc(0,m_file);␊
225 }␊
226 m_state=Reading;␊
227}␊
228␊
229void Store::release(portable_off_t pos)␊
230{␊
231 STORE_ASSERT(m_state==Reading);␊
232 //printf("%x: Store::release\n",(int)pos);␊
233 STORE_ASSERT(pos>0 && (pos & (BLOCK_SIZE-1))==0);␊
234 // goto end of the block␊
235 portable_off_t cur = pos, next;␊
236 while (1)␊
237 {␊
238 // add new node to the free list␊
239 Node *node = new Node;␊
240 node->next = m_head;␊
241 node->pos = cur;␊
242␊
243 m_head = node;␊
244 // goto the end of cur block␊
245 if (portable_fseek(m_file,cur+BLOCK_SIZE-BLOCK_POINTER_SIZE,SEEK_SET)==-1)␊
246 {␊
247 fprintf(stderr,"Store::release: Error seeking to position %d: %s\n",␊
248 (int)(cur+BLOCK_SIZE-BLOCK_POINTER_SIZE),strerror(errno));␊
249 exit(1);␊
250 }␊
251 // read pointer to next block␊
252 if (fread(&next,BLOCK_POINTER_SIZE,1,m_file)!=1)␊
253 {␊
254 fprintf(stderr,"Store::release: Error reading from store: %s\n",strerror(errno));␊
255 exit(1);␊
256 }␊
257 if (next==0) break; // found end of list -> cur is last element␊
258 STORE_ASSERT((next & (BLOCK_SIZE-1))==0);␊
259 cur = next;␊
260 //printf("%x: Store::release\n",(int)cur);␊
261 }␊
262}␊
263␊
264void Store::seek(portable_off_t pos)␊
265{␊
266 STORE_ASSERT(m_state==Reading);␊
267 //printf("%x: Store::seek\n",(int)pos);␊
268 if (portable_fseek(m_file,pos,SEEK_SET)==-1)␊
269 {␊
270 fprintf(stderr,"Store::seek: Error seeking to position %d: %s\n",␊
271 (int)pos,strerror(errno));␊
272 exit(1);␊
273 }␊
274 STORE_ASSERT((pos&(BLOCK_SIZE-1))==0);␊
275}␊
276␊
277int Store::read(char *buf,uint size)␊
278{␊
279 STORE_ASSERT(m_state==Reading);␊
280 //printf("%x: Store::read total=%d\n",(int)portable_ftell(m_file),size);␊
281 do␊
282 {␊
283 portable_off_t curPos = portable_ftell(m_file);␊
284 int bytesInBlock = BLOCK_SIZE - BLOCK_POINTER_SIZE - (curPos & (BLOCK_SIZE-1));␊
285 int bytesLeft = bytesInBlock<(int)size ? (int)size-bytesInBlock : 0;␊
286 int numBytes = size - bytesLeft;␊
287 //printf(" Store::read: pos=%x num=%d left=%d\n",(int)curPos,numBytes,bytesLeft);␊
288␊
289 if (numBytes>0)␊
290 {␊
291 //printf("%x: Store::read: %d out of %d bytes\n",(int)portable_ftell(m_file),numBytes,size);␊
292 if ((int)fread(buf,1,numBytes,m_file)!=numBytes)␊
293 {␊
294 fprintf(stderr,"Error reading from store: %s\n",strerror(errno));␊
295 exit(1);␊
296 }␊
297 m_reads++;␊
298 }␊
299 if (bytesLeft>0)␊
300 {␊
301 portable_off_t newPos;␊
302 // read offset of the next block␊
303 STORE_ASSERT(((portable_ftell(m_file)+BLOCK_POINTER_SIZE)&(BLOCK_SIZE-1))==0);␊
304 if (fread((char *)&newPos,BLOCK_POINTER_SIZE,1,m_file)!=1)␊
305 {␊
306 fprintf(stderr,"Error reading from store: %s\n",strerror(errno));␊
307 exit(1);␊
308 }␊
309 //printf("%x: Store::read: continue in next block, %d bytes to go\n",(int)newPos,bytesLeft);␊
310 //printf(" Store::read: next block=%x\n",(int)newPos);␊
311 STORE_ASSERT(newPos!=0);␊
312 STORE_ASSERT((newPos&(BLOCK_SIZE-1))==0);␊
313 curPos = newPos;␊
314 // move to next block␊
315 if (portable_fseek(m_file,curPos,SEEK_SET)==-1)␊
316 {␊
317 fprintf(stderr,"Store::read: Error seeking to position %d: %s\n",␊
318 (int)curPos,strerror(errno));␊
319 exit(1);␊
320 }␊
321 }␊
322␊
323 size-=numBytes;␊
324 buf+=numBytes;␊
325 }␊
326 while (size>0);␊
327 return size;␊
328}␊
329␊
330void Store::printFreeList()␊
331{␊
332 printf("FreeList: ");␊
333 portable_off_t pos = m_head->pos;␊
334 while (pos)␊
335 {␊
336 printf("%x ",(int)pos);␊
337 m_head = m_head->next;␊
338 }␊
339 printf("\n");␊
340}␊
341␊
342void Store::printStats()␊
343{␊
344 printf("ObjStore: block size %d bytes, total size %ld blocks, wrote %d blocks, read %d blocks\n",␊
345 BLOCK_SIZE,(long)(m_front/BLOCK_SIZE),m_reads,m_writes);␊
346}␊
347␊
348#ifdef STORE_TEST␊
349␊
350int main()␊
351{␊
352 printf("sizeof(portable_off_t)=%d\n",(int)sizeof(portable_off_t));␊
353 Store s;␊
354 if (s.open("test.db")==0)␊
355 {␊
356 const char *str1 = "This is a test message... ";␊
357 const char *str2 = "Another message. ";␊
358␊
359 int i,j;␊
360 for (j=0;j<5;j++)␊
361 {␊
362 char buf[100];␊
363␊
364 portable_off_t handle = s.alloc();␊
365 for (i=0;i<1000000000;i++)␊
366 {␊
367 s.write(str1,strlen(str1)+1);␊
368 }␊
369 s.end();␊
370 portable_off_t handle2 = s.alloc();␊
371 for (i=0;i<10;i++)␊
372 {␊
373 s.write(str2,strlen(str2)+1);␊
374 }␊
375 s.end();␊
376␊
377 s.seek(handle);␊
378 for (i=0;i<3;i++)␊
379 {␊
380 s.read(buf,strlen(str1)+1);␊
381 printf("i=%d Read: %s\n",i,buf);␊
382 }␊
383␊
384 s.release(handle);␊
385␊
386 s.seek(handle2);␊
387 for (i=0;i<3;i++)␊
388 {␊
389 s.read(buf,strlen(str2)+1);␊
390 printf("i=%d Read: %s\n",i,buf);␊
391 }␊
392␊
393 s.release(handle2);␊
394 }␊
395␊
396 s.close();␊
397 }␊
398 else␊
399 {␊
400 printf("Open failed! %s\n",strerror(errno));␊
401 }␊
402}␊
403␊
404#endif␊
405␊
406

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