| 1 | #ifndef lint |
| 2 | static char sccsid[] = "@(#)dbm.c 4.5 (Berkeley) %G%"; |
| 3 | #endif |
| 4 | |
| 5 | #include "dbm.h" |
| 6 | #undef NULL |
| 7 | #include <sys/types.h> |
| 8 | #undef setbit |
| 9 | #include <sys/stat.h> |
| 10 | |
| 11 | dbminit(file) |
| 12 | char *file; |
| 13 | { |
| 14 | struct stat statb; |
| 15 | |
| 16 | dbrdonly = 0; |
| 17 | strcpy(pagbuf, file); |
| 18 | strcat(pagbuf, ".pag"); |
| 19 | pagf = open(pagbuf, 2); |
| 20 | if (pagf < 0) { |
| 21 | pagf = open(pagbuf, 0); |
| 22 | dbrdonly = 1; |
| 23 | } |
| 24 | |
| 25 | strcpy(pagbuf, file); |
| 26 | strcat(pagbuf, ".dir"); |
| 27 | dirf = open(pagbuf, 2); |
| 28 | if (dirf < 0) { |
| 29 | dirf = open(pagbuf, 0); |
| 30 | dbrdonly = 1; |
| 31 | } |
| 32 | if(pagf < 0 || dirf < 0) { |
| 33 | printf("dbm: %s: cannot open database\n", file); |
| 34 | return(-1); |
| 35 | } |
| 36 | fstat(dirf, &statb); |
| 37 | maxbno = statb.st_size*BYTESIZ-1; |
| 38 | return(0); |
| 39 | } |
| 40 | |
| 41 | long |
| 42 | forder(key) |
| 43 | datum key; |
| 44 | { |
| 45 | long hash; |
| 46 | |
| 47 | hash = calchash(key); |
| 48 | for(hmask=0;; hmask=(hmask<<1)+1) { |
| 49 | blkno = hash & hmask; |
| 50 | bitno = blkno + hmask; |
| 51 | if(getbit() == 0) |
| 52 | break; |
| 53 | } |
| 54 | return(blkno); |
| 55 | } |
| 56 | |
| 57 | datum |
| 58 | fetch(key) |
| 59 | datum key; |
| 60 | { |
| 61 | register i; |
| 62 | datum item; |
| 63 | |
| 64 | dbm_access(calchash(key)); |
| 65 | for(i=0;; i+=2) { |
| 66 | item = makdatum(pagbuf, i); |
| 67 | if(item.dptr == NULL) |
| 68 | return(item); |
| 69 | if(cmpdatum(key, item) == 0) { |
| 70 | item = makdatum(pagbuf, i+1); |
| 71 | if(item.dptr == NULL) |
| 72 | printf("dbm: items not in pairs\n"); |
| 73 | return(item); |
| 74 | } |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | delete(key) |
| 79 | datum key; |
| 80 | { |
| 81 | register i; |
| 82 | datum item; |
| 83 | |
| 84 | if (dbrdonly) |
| 85 | return -1; |
| 86 | dbm_access(calchash(key)); |
| 87 | for(i=0;; i+=2) { |
| 88 | item = makdatum(pagbuf, i); |
| 89 | if(item.dptr == NULL) |
| 90 | return(-1); |
| 91 | if(cmpdatum(key, item) == 0) { |
| 92 | delitem(pagbuf, i); |
| 93 | delitem(pagbuf, i); |
| 94 | break; |
| 95 | } |
| 96 | } |
| 97 | lseek(pagf, blkno*PBLKSIZ, 0); |
| 98 | write(pagf, pagbuf, PBLKSIZ); |
| 99 | return(0); |
| 100 | } |
| 101 | |
| 102 | store(key, dat) |
| 103 | datum key, dat; |
| 104 | { |
| 105 | register i; |
| 106 | datum item; |
| 107 | char ovfbuf[PBLKSIZ]; |
| 108 | |
| 109 | if (dbrdonly) |
| 110 | return -1; |
| 111 | loop: |
| 112 | dbm_access(calchash(key)); |
| 113 | for(i=0;; i+=2) { |
| 114 | item = makdatum(pagbuf, i); |
| 115 | if(item.dptr == NULL) |
| 116 | break; |
| 117 | if(cmpdatum(key, item) == 0) { |
| 118 | delitem(pagbuf, i); |
| 119 | delitem(pagbuf, i); |
| 120 | break; |
| 121 | } |
| 122 | } |
| 123 | i = additem(pagbuf, key); |
| 124 | if(i < 0) |
| 125 | goto split; |
| 126 | if(additem(pagbuf, dat) < 0) { |
| 127 | delitem(pagbuf, i); |
| 128 | goto split; |
| 129 | } |
| 130 | lseek(pagf, blkno*PBLKSIZ, 0); |
| 131 | write(pagf, pagbuf, PBLKSIZ); |
| 132 | return (0); |
| 133 | |
| 134 | split: |
| 135 | if(key.dsize+dat.dsize+3*sizeof(short) >= PBLKSIZ) { |
| 136 | printf("dbm: entry too big\n"); |
| 137 | return (-1); |
| 138 | } |
| 139 | clrbuf(ovfbuf, PBLKSIZ); |
| 140 | for(i=0;;) { |
| 141 | item = makdatum(pagbuf, i); |
| 142 | if(item.dptr == NULL) |
| 143 | break; |
| 144 | if(calchash(item) & (hmask+1)) { |
| 145 | additem(ovfbuf, item); |
| 146 | delitem(pagbuf, i); |
| 147 | item = makdatum(pagbuf, i); |
| 148 | if(item.dptr == NULL) { |
| 149 | printf("dbm: split not paired\n"); |
| 150 | break; |
| 151 | } |
| 152 | additem(ovfbuf, item); |
| 153 | delitem(pagbuf, i); |
| 154 | continue; |
| 155 | } |
| 156 | i += 2; |
| 157 | } |
| 158 | lseek(pagf, blkno*PBLKSIZ, 0); |
| 159 | write(pagf, pagbuf, PBLKSIZ); |
| 160 | lseek(pagf, (blkno+hmask+1)*PBLKSIZ, 0); |
| 161 | write(pagf, ovfbuf, PBLKSIZ); |
| 162 | setbit(); |
| 163 | goto loop; |
| 164 | } |
| 165 | |
| 166 | datum |
| 167 | firstkey() |
| 168 | { |
| 169 | return(firsthash(0L)); |
| 170 | } |
| 171 | |
| 172 | datum |
| 173 | nextkey(key) |
| 174 | datum key; |
| 175 | { |
| 176 | register i; |
| 177 | datum item, bitem; |
| 178 | long hash; |
| 179 | int f; |
| 180 | |
| 181 | hash = calchash(key); |
| 182 | dbm_access(hash); |
| 183 | f = 1; |
| 184 | for(i=0;; i+=2) { |
| 185 | item = makdatum(pagbuf, i); |
| 186 | if(item.dptr == NULL) |
| 187 | break; |
| 188 | if(cmpdatum(key, item) <= 0) |
| 189 | continue; |
| 190 | if(f || cmpdatum(bitem, item) < 0) { |
| 191 | bitem = item; |
| 192 | f = 0; |
| 193 | } |
| 194 | } |
| 195 | if(f == 0) |
| 196 | return(bitem); |
| 197 | hash = hashinc(hash); |
| 198 | if(hash == 0) |
| 199 | return(item); |
| 200 | return(firsthash(hash)); |
| 201 | } |
| 202 | |
| 203 | datum |
| 204 | firsthash(hash) |
| 205 | long hash; |
| 206 | { |
| 207 | register i; |
| 208 | datum item, bitem; |
| 209 | |
| 210 | loop: |
| 211 | dbm_access(hash); |
| 212 | bitem = makdatum(pagbuf, 0); |
| 213 | for(i=2;; i+=2) { |
| 214 | item = makdatum(pagbuf, i); |
| 215 | if(item.dptr == NULL) |
| 216 | break; |
| 217 | if(cmpdatum(bitem, item) < 0) |
| 218 | bitem = item; |
| 219 | } |
| 220 | if(bitem.dptr != NULL) |
| 221 | return(bitem); |
| 222 | hash = hashinc(hash); |
| 223 | if(hash == 0) |
| 224 | return(item); |
| 225 | goto loop; |
| 226 | } |
| 227 | |
| 228 | dbm_access(hash) |
| 229 | long hash; |
| 230 | { |
| 231 | static long oldb = -1; |
| 232 | |
| 233 | for(hmask=0;; hmask=(hmask<<1)+1) { |
| 234 | blkno = hash & hmask; |
| 235 | bitno = blkno + hmask; |
| 236 | if(getbit() == 0) |
| 237 | break; |
| 238 | } |
| 239 | if(blkno != oldb) { |
| 240 | clrbuf(pagbuf, PBLKSIZ); |
| 241 | lseek(pagf, blkno*PBLKSIZ, 0); |
| 242 | read(pagf, pagbuf, PBLKSIZ); |
| 243 | chkblk(pagbuf); |
| 244 | oldb = blkno; |
| 245 | } |
| 246 | } |
| 247 | |
| 248 | getbit() |
| 249 | { |
| 250 | long bn; |
| 251 | register b, i, n; |
| 252 | static oldb = -1; |
| 253 | |
| 254 | if(bitno > maxbno) |
| 255 | return(0); |
| 256 | n = bitno % BYTESIZ; |
| 257 | bn = bitno / BYTESIZ; |
| 258 | i = bn % DBLKSIZ; |
| 259 | b = bn / DBLKSIZ; |
| 260 | if(b != oldb) { |
| 261 | clrbuf(dirbuf, DBLKSIZ); |
| 262 | lseek(dirf, (long)b*DBLKSIZ, 0); |
| 263 | read(dirf, dirbuf, DBLKSIZ); |
| 264 | oldb = b; |
| 265 | } |
| 266 | if(dirbuf[i] & (1<<n)) |
| 267 | return(1); |
| 268 | return(0); |
| 269 | } |
| 270 | |
| 271 | setbit() |
| 272 | { |
| 273 | long bn; |
| 274 | register i, n, b; |
| 275 | |
| 276 | if (dbrdonly) |
| 277 | return -1; |
| 278 | if(bitno > maxbno) { |
| 279 | maxbno = bitno; |
| 280 | getbit(); |
| 281 | } |
| 282 | n = bitno % BYTESIZ; |
| 283 | bn = bitno / BYTESIZ; |
| 284 | i = bn % DBLKSIZ; |
| 285 | b = bn / DBLKSIZ; |
| 286 | dirbuf[i] |= 1<<n; |
| 287 | lseek(dirf, (long)b*DBLKSIZ, 0); |
| 288 | write(dirf, dirbuf, DBLKSIZ); |
| 289 | } |
| 290 | |
| 291 | clrbuf(cp, n) |
| 292 | register char *cp; |
| 293 | register n; |
| 294 | { |
| 295 | |
| 296 | do |
| 297 | *cp++ = 0; |
| 298 | while(--n); |
| 299 | } |
| 300 | |
| 301 | datum |
| 302 | makdatum(buf, n) |
| 303 | char buf[PBLKSIZ]; |
| 304 | { |
| 305 | register short *sp; |
| 306 | register t; |
| 307 | datum item; |
| 308 | |
| 309 | sp = (short *)buf; |
| 310 | if(n < 0 || n >= sp[0]) |
| 311 | goto null; |
| 312 | t = PBLKSIZ; |
| 313 | if(n > 0) |
| 314 | t = sp[n+1-1]; |
| 315 | item.dptr = buf+sp[n+1]; |
| 316 | item.dsize = t - sp[n+1]; |
| 317 | return(item); |
| 318 | |
| 319 | null: |
| 320 | item.dptr = NULL; |
| 321 | item.dsize = 0; |
| 322 | return(item); |
| 323 | } |
| 324 | |
| 325 | cmpdatum(d1, d2) |
| 326 | datum d1, d2; |
| 327 | { |
| 328 | register n; |
| 329 | register char *p1, *p2; |
| 330 | |
| 331 | n = d1.dsize; |
| 332 | if(n != d2.dsize) |
| 333 | return(n - d2.dsize); |
| 334 | if(n == 0) |
| 335 | return(0); |
| 336 | p1 = d1.dptr; |
| 337 | p2 = d2.dptr; |
| 338 | do |
| 339 | if(*p1++ != *p2++) |
| 340 | return(*--p1 - *--p2); |
| 341 | while(--n); |
| 342 | return(0); |
| 343 | } |
| 344 | |
| 345 | int hitab[16] |
| 346 | /* ken's |
| 347 | { |
| 348 | 055,043,036,054,063,014,004,005, |
| 349 | 010,064,077,000,035,027,025,071, |
| 350 | }; |
| 351 | */ |
| 352 | = { 61, 57, 53, 49, 45, 41, 37, 33, |
| 353 | 29, 25, 21, 17, 13, 9, 5, 1, |
| 354 | }; |
| 355 | long hltab[64] |
| 356 | = { |
| 357 | 06100151277L,06106161736L,06452611562L,05001724107L, |
| 358 | 02614772546L,04120731531L,04665262210L,07347467531L, |
| 359 | 06735253126L,06042345173L,03072226605L,01464164730L, |
| 360 | 03247435524L,07652510057L,01546775256L,05714532133L, |
| 361 | 06173260402L,07517101630L,02431460343L,01743245566L, |
| 362 | 00261675137L,02433103631L,03421772437L,04447707466L, |
| 363 | 04435620103L,03757017115L,03641531772L,06767633246L, |
| 364 | 02673230344L,00260612216L,04133454451L,00615531516L, |
| 365 | 06137717526L,02574116560L,02304023373L,07061702261L, |
| 366 | 05153031405L,05322056705L,07401116734L,06552375715L, |
| 367 | 06165233473L,05311063631L,01212221723L,01052267235L, |
| 368 | 06000615237L,01075222665L,06330216006L,04402355630L, |
| 369 | 01451177262L,02000133436L,06025467062L,07121076461L, |
| 370 | 03123433522L,01010635225L,01716177066L,05161746527L, |
| 371 | 01736635071L,06243505026L,03637211610L,01756474365L, |
| 372 | 04723077174L,03642763134L,05750130273L,03655541561L, |
| 373 | }; |
| 374 | |
| 375 | long |
| 376 | hashinc(hash) |
| 377 | long hash; |
| 378 | { |
| 379 | long bit; |
| 380 | |
| 381 | hash &= hmask; |
| 382 | bit = hmask+1; |
| 383 | for(;;) { |
| 384 | bit >>= 1; |
| 385 | if(bit == 0) |
| 386 | return(0L); |
| 387 | if((hash&bit) == 0) |
| 388 | return(hash|bit); |
| 389 | hash &= ~bit; |
| 390 | } |
| 391 | } |
| 392 | |
| 393 | long |
| 394 | calchash(item) |
| 395 | datum item; |
| 396 | { |
| 397 | register i, j, f; |
| 398 | long hashl; |
| 399 | int hashi; |
| 400 | |
| 401 | hashl = 0; |
| 402 | hashi = 0; |
| 403 | for(i=0; i<item.dsize; i++) { |
| 404 | f = item.dptr[i]; |
| 405 | for(j=0; j<BYTESIZ; j+=4) { |
| 406 | hashi += hitab[f&017]; |
| 407 | hashl += hltab[hashi&63]; |
| 408 | f >>= 4; |
| 409 | } |
| 410 | } |
| 411 | return(hashl); |
| 412 | } |
| 413 | |
| 414 | delitem(buf, n) |
| 415 | char buf[PBLKSIZ]; |
| 416 | { |
| 417 | register short *sp; |
| 418 | register i1, i2, i3; |
| 419 | |
| 420 | sp = (short *)buf; |
| 421 | if(n < 0 || n >= sp[0]) |
| 422 | goto bad; |
| 423 | i1 = sp[n+1]; |
| 424 | i2 = PBLKSIZ; |
| 425 | if(n > 0) |
| 426 | i2 = sp[n+1-1]; |
| 427 | i3 = sp[sp[0]+1-1]; |
| 428 | if(i2 > i1) |
| 429 | while(i1 > i3) { |
| 430 | i1--; |
| 431 | i2--; |
| 432 | buf[i2] = buf[i1]; |
| 433 | buf[i1] = 0; |
| 434 | } |
| 435 | i2 -= i1; |
| 436 | for(i1=n+1; i1<sp[0]; i1++) |
| 437 | sp[i1+1-1] = sp[i1+1] + i2; |
| 438 | sp[0]--; |
| 439 | sp[sp[0]+1] = 0; |
| 440 | return; |
| 441 | |
| 442 | bad: |
| 443 | printf("dbm: bad delitem\n"); |
| 444 | abort(); |
| 445 | } |
| 446 | |
| 447 | additem(buf, item) |
| 448 | char buf[PBLKSIZ]; |
| 449 | datum item; |
| 450 | { |
| 451 | register short *sp; |
| 452 | register i1, i2; |
| 453 | |
| 454 | sp = (short *)buf; |
| 455 | i1 = PBLKSIZ; |
| 456 | if(sp[0] > 0) |
| 457 | i1 = sp[sp[0]+1-1]; |
| 458 | i1 -= item.dsize; |
| 459 | i2 = (sp[0]+2) * sizeof(short); |
| 460 | if(i1 <= i2) |
| 461 | return(-1); |
| 462 | sp[sp[0]+1] = i1; |
| 463 | for(i2=0; i2<item.dsize; i2++) { |
| 464 | buf[i1] = item.dptr[i2]; |
| 465 | i1++; |
| 466 | } |
| 467 | sp[0]++; |
| 468 | return(sp[0]-1); |
| 469 | } |
| 470 | |
| 471 | chkblk(buf) |
| 472 | char buf[PBLKSIZ]; |
| 473 | { |
| 474 | register short *sp; |
| 475 | register t, i; |
| 476 | |
| 477 | sp = (short *)buf; |
| 478 | t = PBLKSIZ; |
| 479 | for(i=0; i<sp[0]; i++) { |
| 480 | if(sp[i+1] > t) |
| 481 | goto bad; |
| 482 | t = sp[i+1]; |
| 483 | } |
| 484 | if(t < (sp[0]+1)*sizeof(short)) |
| 485 | goto bad; |
| 486 | return; |
| 487 | |
| 488 | bad: |
| 489 | printf("dbm: bad block\n"); |
| 490 | abort(); |
| 491 | clrbuf(buf, PBLKSIZ); |
| 492 | } |