1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484
|
/******************************************************************************
*
*
*
*
* Copyright (C) 1997-2015 by Dimitri van Heesch.
*
* Permission to use, copy, modify, and distribute this software and its
* documentation under the terms of the GNU General Public License is hereby
* granted. No representations are made about the suitability of this software
* for any purpose. It is provided "as is" without express or implied warranty.
* See the GNU General Public License for more details.
*
* Documents produced by Doxygen are derivative works derived from the
* input used in their production; they are not affected by this license.
*
*/
#include "store.h"
#include "portable.h"
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <assert.h>
#include <ctype.h>
#define BLOCK_SIZE 512 // should be >8 and a power of 2
#define BLOCK_POINTER_SIZE sizeof(portable_off_t)
#define ASSERTS_ENABLED
#ifdef ASSERTS_ENABLED
#define STORE_ASSERT(x) assert(x)
#else
#define STORE_ASSERT(x)
#endif
// Decide to use ftell or keep track of the current file pointer ourselves.
// Since valgrind shows that calling ftell has the unwanted side-effect of
// writing some uninitialized bytes (!) it might be better (and faster) to keep track
// of the current pointer ourselves.
#define USE_FTELL 0
//------------------------------------------------------------------------------------
Store::Store()
{
m_file = 0;
m_front = 0;
m_cur = 0;
m_head = 0;
m_state = Init;
m_reads = 0;
m_writes = 0;
}
Store::~Store()
{
if (m_file) fclose(m_file);
// clean up free list
while (m_head)
{
Node *node = m_head;
m_head = node->next;
delete node;
}
}
int Store::open(const char *name)
{
int i;
STORE_ASSERT(m_state==Init);
if (m_file) return 0; // already open
m_file = portable_fopen(name,"w+b");
if (m_file==0) return -1;
// first block serves as header, so offset=0 can be used as the end of the list.
for (i=0;i<BLOCK_SIZE/8;i++)
{
fputc('D',m_file);
fputc('O',m_file);
fputc('X',m_file);
fputc('Y',m_file);
fputc('G',m_file);
fputc('E',m_file);
fputc('N',m_file);
fputc(0,m_file);
}
m_front = BLOCK_SIZE;
m_cur = BLOCK_SIZE;
m_head = 0;
m_state = Reading;
return 0;
}
void Store::close()
{
if (m_file) fclose(m_file);
m_file=0;
m_state = Init;
}
portable_off_t Store::alloc()
{
STORE_ASSERT(m_state==Reading);
m_state=Writing;
portable_off_t pos;
if (m_head==0) // allocate new block
{
//printf("alloc: new block, pos=%lld\n",(long long)m_front);
if (portable_fseek(m_file,0,SEEK_END)==-1) // go to end of the file
{
fprintf(stderr,"Store::alloc: Error seeking to end of file: %s\n",strerror(errno));
exit(1);
}
#if USE_FTELL
pos = portable_ftell(m_file);
STORE_ASSERT( (pos & (BLOCK_SIZE-1))==0 );
m_front = pos + BLOCK_SIZE; // move front to end of this block
#else
m_cur = m_front;
pos = m_cur;
STORE_ASSERT( (pos & (BLOCK_SIZE-1))==0 );
m_front = pos + BLOCK_SIZE;
#endif
}
else // reuse freed block
{
//printf("alloc: reuse block: pos=%lld\n",(long long)m_head->pos);
Node *node = m_head;
pos = node->pos;
// point head to next free item
m_head = node->next;
delete node;
// move to start of the block
if (portable_fseek(m_file,pos,SEEK_SET)==-1)
{
fprintf(stderr,"Store::alloc: Error seeking to position %d: %s\n",
(int)pos,strerror(errno));
exit(1);
}
m_cur = pos;
STORE_ASSERT( (pos & (BLOCK_SIZE-1))==0 );
}
//printf("%x: Store::alloc\n",(int)pos);
return pos;
}
int Store::write(const char *buf,uint size)
{
STORE_ASSERT(m_state==Writing);
//printf("%x: Store::write\n",(int)portable_ftell(m_file));
do
{
#if USE_FTELL
portable_off_t curPos = portable_ftell(m_file);
#else
portable_off_t curPos = m_cur;
#endif
int bytesInBlock = (int)(BLOCK_SIZE - BLOCK_POINTER_SIZE - (curPos & (BLOCK_SIZE-1)));
int bytesLeft = bytesInBlock<(int)size ? (int)size-bytesInBlock : 0;
int numBytes = size - bytesLeft;
STORE_ASSERT(bytesInBlock>=0);
STORE_ASSERT(numBytes<=(int)(BLOCK_SIZE-BLOCK_POINTER_SIZE));
if (numBytes>0)
{
if ((int)fwrite(buf,1,numBytes,m_file)!=numBytes)
{
fprintf(stderr,"Error writing: %s\n",strerror(errno));
exit(1);
}
m_cur+=numBytes;
m_writes++;
}
if (bytesLeft>0) // still more bytes to write
{
#if USE_FTELL
STORE_ASSERT(((portable_ftell(m_file)+BLOCK_POINTER_SIZE)&(BLOCK_SIZE-1))==0);
#else
STORE_ASSERT(((m_cur+BLOCK_POINTER_SIZE)&(BLOCK_SIZE-1))==0);
#endif
// allocate new block
if (m_head==0) // no free blocks to reuse
{
//printf("%x: Store::write: new: pos=%x\n",(int)m_front,(int)portable_ftell(m_file));
// write pointer to next block
if (fwrite(&m_front,BLOCK_POINTER_SIZE,1,m_file)!=1)
{
fprintf(stderr,"Error writing to store: %s\n",strerror(errno));
exit(1);
}
m_cur+=BLOCK_POINTER_SIZE;
#if USE_FTELL
STORE_ASSERT(portable_ftell(m_file)==(curPos&~(BLOCK_SIZE-1))+BLOCK_SIZE);
#else
STORE_ASSERT(m_cur==(curPos&~(BLOCK_SIZE-1))+BLOCK_SIZE);
#endif
// move to next block
if (portable_fseek(m_file,0,SEEK_END)==-1) // go to end of the file
{
fprintf(stderr,"Store::alloc: Error seeking to end of file: %s\n",strerror(errno));
exit(1);
}
m_cur=m_front;
#if USE_FTELL
STORE_ASSERT(portable_ftell(m_file)==m_front);
#else
STORE_ASSERT(m_cur==m_front);
#endif
// move front to the next of the block
m_front+=BLOCK_SIZE;
}
else // reuse block from the free list
{
// write pointer to next block
if (fwrite(&m_head->pos,BLOCK_POINTER_SIZE,1,m_file)!=1)
{
fprintf(stderr,"Error writing to store: %s\n",strerror(errno));
exit(1);
}
Node *node = m_head;
portable_off_t pos = node->pos;
// point head to next free item
m_head = node->next;
delete node;
// move to start of the block
if (portable_fseek(m_file,pos,SEEK_SET)==-1)
{
fprintf(stderr,"Store::write: Error seeking to position %d: %s\n",
(int)pos,strerror(errno));
exit(1);
}
m_cur = pos;
//printf("%x: Store::write: reuse\n",(int)pos);
}
}
size-=numBytes;
buf+=numBytes;
}
while (size>0);
return size;
}
void Store::end()
{
STORE_ASSERT(m_state==Writing);
#if USE_FTELL
portable_off_t curPos = portable_ftell(m_file);
#else
portable_off_t curPos = m_cur;
#endif
int bytesInBlock = (int)(BLOCK_SIZE - (curPos & (BLOCK_SIZE-1)));
//printf("%x: Store::end erasing %x bytes\n",(int)curPos&~(BLOCK_SIZE-1),bytesInBlock);
//printf("end: bytesInBlock=%x\n",bytesInBlock);
// zero out rest of the block
int i;
for (i=0;i<bytesInBlock;i++)
{
fputc(0,m_file);
}
m_state=Reading;
}
void Store::release(portable_off_t pos)
{
STORE_ASSERT(m_state==Reading);
//printf("release: block pos=%lld\n",(long long)pos);
STORE_ASSERT(pos>0 && (pos & (BLOCK_SIZE-1))==0);
// goto end of the block
portable_off_t cur = pos, next;
while (1)
{
// add new node to the free list
Node *node = new Node;
node->next = m_head;
node->pos = cur;
m_head = node;
// goto the end of cur block
if (portable_fseek(m_file,cur+BLOCK_SIZE-BLOCK_POINTER_SIZE,SEEK_SET)==-1)
{
fprintf(stderr,"Store::release: Error seeking to position %d: %s\n",
(int)(cur+BLOCK_SIZE-BLOCK_POINTER_SIZE),strerror(errno));
exit(1);
}
// read pointer to next block
if (fread(&next,BLOCK_POINTER_SIZE,1,m_file)!=1)
{
fprintf(stderr,"Store::release: Error reading from store: %s\n",strerror(errno));
exit(1);
}
m_cur = cur+BLOCK_SIZE;
if (next==0) break; // found end of list -> cur is last element
STORE_ASSERT((next & (BLOCK_SIZE-1))==0);
cur = next;
//printf("%x: Store::release\n",(int)cur);
}
}
void Store::seek(portable_off_t pos)
{
STORE_ASSERT(m_state==Reading);
//printf("%x: Store::seek\n",(int)pos);
if (portable_fseek(m_file,pos,SEEK_SET)==-1)
{
fprintf(stderr,"Store::seek: Error seeking to position %d: %s\n",
(int)pos,strerror(errno));
exit(1);
}
m_cur = pos;
STORE_ASSERT((pos&(BLOCK_SIZE-1))==0);
}
int Store::read(char *buf,uint size)
{
STORE_ASSERT(m_state==Reading);
//printf("%x: Store::read total=%d\n",(int)portable_ftell(m_file),size);
do
{
#if USE_FTELL
portable_off_t curPos = portable_ftell(m_file);
#else
portable_off_t curPos = m_cur;
#endif
int bytesInBlock = (int)(BLOCK_SIZE - BLOCK_POINTER_SIZE - (curPos & (BLOCK_SIZE-1)));
int bytesLeft = bytesInBlock<(int)size ? (int)size-bytesInBlock : 0;
int numBytes = size - bytesLeft;
//printf(" Store::read: pos=%x num=%d left=%d\n",(int)curPos,numBytes,bytesLeft);
if (numBytes>0)
{
//printf("%x: Store::read: %d out of %d bytes\n",(int)portable_ftell(m_file),numBytes,size);
if ((int)fread(buf,1,numBytes,m_file)!=numBytes)
{
fprintf(stderr,"Error reading from store: %s\n",strerror(errno));
exit(1);
}
m_cur+=numBytes;
m_reads++;
}
if (bytesLeft>0)
{
portable_off_t newPos;
// read offset of the next block
#if USE_FTELL
STORE_ASSERT(((portable_ftell(m_file)+BLOCK_POINTER_SIZE)&(BLOCK_SIZE-1))==0);
#else
STORE_ASSERT(((m_cur+BLOCK_POINTER_SIZE)&(BLOCK_SIZE-1))==0);
#endif
if (fread((char *)&newPos,BLOCK_POINTER_SIZE,1,m_file)!=1)
{
fprintf(stderr,"Error reading from store: %s\n",strerror(errno));
exit(1);
}
//printf("%x: Store::read: continue in next block, %d bytes to go\n",(int)newPos,bytesLeft);
//printf(" Store::read: next block=%x\n",(int)newPos);
STORE_ASSERT(newPos!=0);
STORE_ASSERT((newPos&(BLOCK_SIZE-1))==0);
curPos = newPos;
// move to next block
if (portable_fseek(m_file,curPos,SEEK_SET)==-1)
{
fprintf(stderr,"Store::read: Error seeking to position %d: %s\n",
(int)curPos,strerror(errno));
exit(1);
}
m_cur = curPos;
}
size-=numBytes;
buf+=numBytes;
}
while (size>0);
return size;
}
void Store::printFreeList()
{
printf("FreeList: ");
while (m_head)
{
portable_off_t pos = m_head->pos;
printf("%x ",(int)pos);
m_head = m_head->next;
}
printf("\n");
}
void Store::printStats()
{
printf("ObjStore: block size %d bytes, total size %ld blocks, wrote %d blocks, read %d blocks\n",
BLOCK_SIZE,(long)(m_front/BLOCK_SIZE),m_reads,m_writes);
}
void Store::dumpBlock(portable_off_t s,portable_off_t e)
{
portable_fseek(m_file,s,SEEK_SET);
int size = (int)(e-s);
uchar *buf = new uchar[size];
if (fread(buf,size,1,m_file)==(size_t)size)
{
int i,j;
for (i=0;i<size;i+=16)
{
printf("%08x: ",(int)s+i);
for (j=i;j<QMIN(size,i+16);j++)
{
printf("%02x ",buf[i+j]);
}
printf(" ");
for (j=i;j<QMIN(size,i+16);j++)
{
printf("%c",(buf[i+j]>=32 && buf[i+j]<128)?buf[i+j]:'.');
}
printf("\n");
}
}
delete[] buf;
portable_fseek(m_file,m_cur,SEEK_SET);
}
#ifdef STORE_TEST
int main()
{
printf("sizeof(portable_off_t)=%d\n",(int)sizeof(portable_off_t));
Store s;
if (s.open("test.db")==0)
{
const char *str1 = "This is a test message... ";
const char *str2 = "Another message. ";
int i,j;
for (j=0;j<5;j++)
{
char buf[100];
portable_off_t handle = s.alloc();
for (i=0;i<1000000000;i++)
{
s.write(str1,strlen(str1)+1);
}
s.end();
portable_off_t handle2 = s.alloc();
for (i=0;i<10;i++)
{
s.write(str2,strlen(str2)+1);
}
s.end();
s.seek(handle);
for (i=0;i<3;i++)
{
s.read(buf,strlen(str1)+1);
printf("i=%d Read: %s\n",i,buf);
}
s.release(handle);
s.seek(handle2);
for (i=0;i<3;i++)
{
s.read(buf,strlen(str2)+1);
printf("i=%d Read: %s\n",i,buf);
}
s.release(handle2);
}
s.close();
}
else
{
printf("Open failed! %s\n",strerror(errno));
}
}
#endif
|