| 1 |
/* |
| 2 |
================================================================== |
| 3 |
N-way hybrid out-of-core merge sort |
| 4 |
Sorts N blocks internally using quicksort, followed by N-way |
| 5 |
merge using priority queue. |
| 6 |
|
| 7 |
Roland Schregle (roland.schregle@{hslu.ch, gmail.com}) |
| 8 |
(c) Fraunhofer Institute for Solar Energy Systems, |
| 9 |
Lucerne University of Applied Sciences & Arts |
| 10 |
================================================================== |
| 11 |
|
| 12 |
$Id $ |
| 13 |
*/ |
| 14 |
|
| 15 |
|
| 16 |
#include "oocsort.h" |
| 17 |
#include <stdio.h> |
| 18 |
#include <stdlib.h> |
| 19 |
#include <string.h> |
| 20 |
|
| 21 |
|
| 22 |
/* Priority queue node */ |
| 23 |
typedef struct { |
| 24 |
OOC_Sort_Key pri; /* Record's priority (sort key) */ |
| 25 |
unsigned blk; /* Block containing record */ |
| 26 |
} OOC_Sort_PQNode; |
| 27 |
|
| 28 |
typedef struct { |
| 29 |
OOC_Sort_PQNode *node; |
| 30 |
unsigned len, tail; |
| 31 |
} OOC_Sort_PQueue; |
| 32 |
|
| 33 |
/* Block descriptor */ |
| 34 |
typedef struct { |
| 35 |
FILE *file; /* Temporary file */ |
| 36 |
char *buf, *head, *tail; /* Associated I/O buffa, |
| 37 |
head/tail pointers */ |
| 38 |
} OOC_Sort_Block; |
| 39 |
|
| 40 |
|
| 41 |
/* Record priority evaluation function */ |
| 42 |
static OOC_Sort_Key (*pri)(const void *); |
| 43 |
|
| 44 |
|
| 45 |
static int OOC_Sort_Compare (const void *rec1, const void *rec2) |
| 46 |
/* Comparison function for internal sorting */ |
| 47 |
{ |
| 48 |
const OOC_Sort_Key pri1 = pri(rec1), pri2 = pri(rec2); |
| 49 |
|
| 50 |
if (!rec1 || !rec2) |
| 51 |
return 0; |
| 52 |
|
| 53 |
if (pri1 < pri2) |
| 54 |
return -1; |
| 55 |
else if (pri1 > pri2) |
| 56 |
return 1; |
| 57 |
else |
| 58 |
return 0; |
| 59 |
} |
| 60 |
|
| 61 |
|
| 62 |
static char *OOC_Sort_Read (OOC_Sort_Block *blk, unsigned recSize) |
| 63 |
/* Read next record from specified block; return pointer to buffa entry |
| 64 |
or NULL on error */ |
| 65 |
{ |
| 66 |
char *rec = NULL; |
| 67 |
|
| 68 |
if (blk -> head >= blk -> tail) { |
| 69 |
/* Input buffa empty; read next block (potentially truncated if last), |
| 70 |
* where tail marks end of buffa */ |
| 71 |
const unsigned long bufSize = blk -> tail - blk -> buf; |
| 72 |
|
| 73 |
if (feof(blk -> file)) |
| 74 |
return NULL; |
| 75 |
|
| 76 |
blk -> head = blk -> buf; |
| 77 |
blk -> tail = blk -> buf + fread(blk -> buf, 1, bufSize, blk -> file); |
| 78 |
|
| 79 |
if (blk -> tail == blk -> head) |
| 80 |
return NULL; |
| 81 |
} |
| 82 |
|
| 83 |
rec = blk -> head; |
| 84 |
blk -> head += recSize; |
| 85 |
|
| 86 |
return rec; |
| 87 |
} |
| 88 |
|
| 89 |
|
| 90 |
static char *OOC_Sort_Peek (OOC_Sort_Block *blk, unsigned recSize) |
| 91 |
/* Return next record from specified block WITHOUT removing from buffa */ |
| 92 |
{ |
| 93 |
char *rec = NULL; |
| 94 |
|
| 95 |
if (rec = OOC_Sort_Read(blk, recSize)) { |
| 96 |
/* Restore buffa head */ |
| 97 |
blk -> head -= recSize; |
| 98 |
} |
| 99 |
|
| 100 |
return rec; |
| 101 |
} |
| 102 |
|
| 103 |
|
| 104 |
static char *OOC_Sort_Write (OOC_Sort_Block *blk, unsigned recSize, |
| 105 |
const char *rec) |
| 106 |
/* Output record to specified block and return pointer to buffa entry |
| 107 |
or NULL on error */ |
| 108 |
{ |
| 109 |
char *res = NULL; |
| 110 |
|
| 111 |
if (blk -> head >= blk -> tail) { |
| 112 |
/* Flush output buffa (tail marks end of buffa) */ |
| 113 |
const unsigned long bufSize = blk -> tail - blk -> buf; |
| 114 |
|
| 115 |
blk -> head = blk -> buf; |
| 116 |
if (fwrite(blk -> buf, 1, bufSize, blk -> file) != bufSize) |
| 117 |
return NULL; |
| 118 |
} |
| 119 |
|
| 120 |
if (!rec) |
| 121 |
return NULL; |
| 122 |
|
| 123 |
memcpy(blk -> head, rec, recSize); |
| 124 |
res = blk -> head; |
| 125 |
blk -> head += recSize; |
| 126 |
|
| 127 |
return res; |
| 128 |
} |
| 129 |
|
| 130 |
|
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#ifdef DEBUG |
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static int OOC_Sort_PQCheck (OOC_Sort_PQueue *pq, unsigned root) |
| 133 |
/* Priority queue sanity check */ |
| 134 |
{ |
| 135 |
unsigned kid; |
| 136 |
|
| 137 |
if (root < pq -> tail) { |
| 138 |
if ((kid = (root << 1) + 1) < pq -> tail) |
| 139 |
if (pq -> node [kid].pri < pq -> node [root].pri) |
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return -1; |
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else return OOC_Sort_PQCheck(pq, kid); |
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|
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if ((kid = kid + 1) < pq -> tail) |
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if (pq -> node [kid].pri < pq -> node [root].pri) |
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return -1; |
| 146 |
else return OOC_Sort_PQCheck(pq, kid); |
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|
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} |
| 149 |
|
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return 0; |
| 151 |
} |
| 152 |
#endif |
| 153 |
|
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|
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static int OOC_Sort_Push (OOC_Sort_PQueue *pq, OOC_Sort_Key pri, |
| 156 |
unsigned blk) |
| 157 |
/* Insert specified block index into priority queue; return block index |
| 158 |
* or -1 if queue is full */ |
| 159 |
{ |
| 160 |
OOC_Sort_PQNode *pqn = pq -> node; |
| 161 |
unsigned kid, root; |
| 162 |
|
| 163 |
if (pq -> tail >= pq -> len) |
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/* Queue full */ |
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return -1; |
| 166 |
|
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/* Append node at tail and re-sort */ |
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kid = pq -> tail++; |
| 169 |
|
| 170 |
while (kid) { |
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root = kid - 1 >> 1; |
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|
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/* Compare with parent node and swap if necessary, else terminate */ |
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if (pri < pqn [root].pri) { |
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pqn [kid].pri = pqn [root].pri; |
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pqn [kid].blk = pqn [root].blk; |
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kid = root; |
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} |
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else break; |
| 180 |
} |
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|
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pqn [kid].pri = pri; |
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pqn [kid].blk = blk; |
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|
| 185 |
#ifdef DEBUG |
| 186 |
if (OOC_Sort_PQCheck(pq, 0) < 0) { |
| 187 |
fprintf(stderr, "OOC_Sort: priority queue inconsistency\n"); |
| 188 |
return -1; |
| 189 |
} |
| 190 |
#endif |
| 191 |
|
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return blk; |
| 193 |
} |
| 194 |
|
| 195 |
|
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static int OOC_Sort_Pop (OOC_Sort_PQueue *pq) |
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/* Remove head of priority queue and return its block index |
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* or -1 if queue is empty */ |
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{ |
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OOC_Sort_PQNode *pqn = pq -> node; |
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OOC_Sort_Key pri; |
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unsigned kid, kid2, root = 0, blk, res; |
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|
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if (!pq -> tail) |
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/* Queue empty */ |
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return -1; |
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|
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res = pqn -> blk; |
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pri = pqn [--pq -> tail].pri; |
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blk = pqn [pq -> tail].blk; |
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|
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/* Replace head with tail node and re-sort */ |
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while ((kid = (root << 1) + 1) < pq -> tail) { |
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/* Compare with with smaller kid and swap if necessary, else |
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* terminate */ |
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if ((kid2 = (kid + 1)) < pq -> tail && pqn [kid2].pri < pqn [kid].pri) |
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kid = kid2; |
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|
| 219 |
if (pri > pqn [kid].pri) { |
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pqn [root].pri = pqn [kid].pri; |
| 221 |
pqn [root].blk = pqn [kid].blk; |
| 222 |
} |
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else break; |
| 224 |
|
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root = kid; |
| 226 |
} |
| 227 |
|
| 228 |
pqn [root].pri = pri; |
| 229 |
pqn [root].blk = blk; |
| 230 |
|
| 231 |
#ifdef DEBUG |
| 232 |
if (OOC_Sort_PQCheck(pq, 0) < 0) { |
| 233 |
fprintf(stderr, "OOC_Sort: priority queue inconsistency\n"); |
| 234 |
return -1; |
| 235 |
} |
| 236 |
#endif |
| 237 |
|
| 238 |
return res; |
| 239 |
} |
| 240 |
|
| 241 |
#if 0 |
| 242 |
int OOC_Sort (const char *inFile, const char *outFile, |
| 243 |
unsigned long blkSize, unsigned recSize, |
| 244 |
OOC_Sort_Key (*priority)(const void *)) |
| 245 |
/* Sort records in inFile and output to outFile by (a) internally |
| 246 |
* quicksorting block of blkSize bytes at a time, then (b) merging them |
| 247 |
* via a priority queue. RecSize specifies the size in bytes of each data |
| 248 |
* record. The priority() callback evaluates a record's priority and must be |
| 249 |
* supplied by the caller. */ |
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{ |
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FILE *in = NULL; |
| 252 |
OOC_Sort_PQueue pqueue; /* Priority queue */ |
| 253 |
OOC_Sort_Block *iBlk = NULL, oBlk; /* Block descriptors */ |
| 254 |
char *rec, *sortBuf = NULL; /* Internal sort buffa */ |
| 255 |
unsigned bufSize, numBlk; |
| 256 |
int b; |
| 257 |
|
| 258 |
/* Set record priority evaluation callback */ |
| 259 |
pri = priority; |
| 260 |
|
| 261 |
/* Round block and buffa size down to nearest multiple of record size */ |
| 262 |
blkSize = (blkSize / recSize) * recSize; |
| 263 |
bufSize = (OOC_SORT_BUFSIZE / recSize) * recSize; |
| 264 |
|
| 265 |
if (!(in = fopen(inFile, "rb"))) { |
| 266 |
fprintf(stderr, "OOC_Sort: failure opening input file %s\n", inFile); |
| 267 |
return -1; |
| 268 |
} |
| 269 |
|
| 270 |
/* Get input file size and number of blocks (rounded up to nearest |
| 271 |
* multiple of block size) */ |
| 272 |
fseek(in, 0, SEEK_END); |
| 273 |
numBlk = (ftell(in) + blkSize - 1) / blkSize; |
| 274 |
rewind(in); |
| 275 |
#else |
| 276 |
|
| 277 |
int OOC_Sort (const char *inFile, const char *outFile, |
| 278 |
unsigned numBlk, unsigned recSize, |
| 279 |
OOC_Sort_Key (*priority)(const void *)) |
| 280 |
/* Sort records in inFile and output to outFile by (a) internally |
| 281 |
* quicksorting numBlk blocks at a time, then (b) merging them via a priority |
| 282 |
* queue. RecSize specifies the size in bytes of each data record. The |
| 283 |
* priority() callback evaluates a record's priority (ordinal index) and |
| 284 |
* must be supplied by the caller. */ |
| 285 |
{ |
| 286 |
FILE *in = NULL; |
| 287 |
OOC_Sort_PQueue pqueue; /* Priority queue */ |
| 288 |
OOC_Sort_Block *iBlk = NULL, oBlk; /* Block descriptors */ |
| 289 |
char *rec, *sortBuf = NULL; /* Internal sort buffa */ |
| 290 |
unsigned long blkSize; |
| 291 |
unsigned bufSize; |
| 292 |
int b; |
| 293 |
|
| 294 |
/* Set record priority evaluation callback */ |
| 295 |
pri = priority; |
| 296 |
|
| 297 |
/* Round buffa size down to nearest multiple of record size */ |
| 298 |
bufSize = (OOC_SORT_BUFSIZE / recSize) * recSize; |
| 299 |
|
| 300 |
if (!(in = fopen(inFile, "rb"))) { |
| 301 |
fprintf(stderr, "OOC_Sort: failure opening input file %s\n", inFile); |
| 302 |
return -1; |
| 303 |
} |
| 304 |
|
| 305 |
/* Get input file size and block size (in number of records) rounded up |
| 306 |
* to nearest multiple of number of blocks */ |
| 307 |
fseek(in, 0, SEEK_END); |
| 308 |
blkSize = (ftell(in) / recSize + numBlk - 1) / numBlk; |
| 309 |
rewind(in); |
| 310 |
#endif |
| 311 |
|
| 312 |
/* Allocate buffa for internal sorting */ |
| 313 |
if (!(sortBuf = malloc(blkSize))) { |
| 314 |
fprintf(stderr, "OOC_Sort: failure allocating internal sort buffer\n"); |
| 315 |
return -1; |
| 316 |
} |
| 317 |
|
| 318 |
/* Allocate input blocks */ |
| 319 |
if (!(iBlk = calloc(numBlk, sizeof(OOC_Sort_Block)))) { |
| 320 |
fprintf(stderr, "OOC_Sort: failure allocating input blocks\n"); |
| 321 |
return -1; |
| 322 |
} |
| 323 |
|
| 324 |
/* =================================================================== |
| 325 |
* Pass 1: Internal quicksort of each input block in sortBuf |
| 326 |
* =================================================================== */ |
| 327 |
|
| 328 |
for (b = 0; b < numBlk; b++) { |
| 329 |
unsigned long numRec; |
| 330 |
|
| 331 |
/* Open temporary file associated with block */ |
| 332 |
if (!(iBlk [b].file = tmpfile())) { |
| 333 |
/* fprintf(stderr, "OOC_Sort: failure opening block file\n"); */ |
| 334 |
perror("OOC_Sort: failure opening block file"); |
| 335 |
return -1; |
| 336 |
} |
| 337 |
|
| 338 |
if (feof(in)) { |
| 339 |
fprintf(stderr, "OOC_Sort: unexpected end of input file %s\n", |
| 340 |
inFile); |
| 341 |
return -1; |
| 342 |
} |
| 343 |
|
| 344 |
/* Read next block (potentially truncated if last) */ |
| 345 |
if (!(numRec = fread(sortBuf, 1, blkSize, in) / recSize)) { |
| 346 |
fprintf(stderr, "OOC_Sort: error reading from input file %s\n", |
| 347 |
inFile); |
| 348 |
return -1; |
| 349 |
} |
| 350 |
|
| 351 |
/* Quicksort block internally and write out to temp file */ |
| 352 |
qsort(sortBuf, numRec, recSize, OOC_Sort_Compare); |
| 353 |
|
| 354 |
if (fwrite(sortBuf, recSize, numRec, iBlk [b].file) != numRec) { |
| 355 |
fprintf(stderr, "OOC_Sort: error writing to block file\n"); |
| 356 |
return -1; |
| 357 |
} |
| 358 |
|
| 359 |
rewind(iBlk [b].file); |
| 360 |
} |
| 361 |
|
| 362 |
/* Close input file and free sort buffa */ |
| 363 |
fclose(in); |
| 364 |
free(sortBuf); |
| 365 |
|
| 366 |
/* Allocate priority queue with numBlk nodes */ |
| 367 |
pqueue.tail = 0; |
| 368 |
pqueue.len = numBlk; |
| 369 |
if (!(pqueue.node = calloc(numBlk, sizeof(OOC_Sort_PQNode)))) { |
| 370 |
fprintf(stderr, "OOC_Sort: failure allocating priority queue\n"); |
| 371 |
return -1; |
| 372 |
} |
| 373 |
|
| 374 |
/* Prepare for pass 2: allocate buffa for each input block and initialise |
| 375 |
* fill priority queue with single record from each block */ |
| 376 |
for (b = 0; b < numBlk; b++) { |
| 377 |
if (!(iBlk [b].buf = malloc(bufSize))) { |
| 378 |
fprintf(stderr, "OOC_Sort: failure allocating input buffer\n"); |
| 379 |
return -1; |
| 380 |
} |
| 381 |
|
| 382 |
/* Peek first record in block file without modifying buffa */ |
| 383 |
iBlk [b].head = iBlk [b].tail = iBlk [b].buf + bufSize; |
| 384 |
if (!(rec = OOC_Sort_Peek(iBlk + b, recSize))) { |
| 385 |
fprintf(stderr, "OOC_Sort: error reading from block file\n"); |
| 386 |
return -1; |
| 387 |
} |
| 388 |
|
| 389 |
/* Insert record into priority queue */ |
| 390 |
if (OOC_Sort_Push(&pqueue, priority(rec), b) < 0) { |
| 391 |
fprintf(stderr, "OOC_Sort: failed priority queue insertion\n"); |
| 392 |
return -1; |
| 393 |
} |
| 394 |
} |
| 395 |
|
| 396 |
/* Allocate output buffa and open output file */ |
| 397 |
if (!(oBlk.file = fopen(outFile, "wb"))) { |
| 398 |
fprintf(stderr, "OOC_Sort: failure opening output file %s\n", outFile); |
| 399 |
return -1; |
| 400 |
} |
| 401 |
|
| 402 |
if (!(oBlk.head = oBlk.buf = malloc(bufSize))) { |
| 403 |
fprintf(stderr, "OOC_Sort: failure allocating output buffer\n"); |
| 404 |
return -1; |
| 405 |
} |
| 406 |
|
| 407 |
/* tail marks end of output buffa */ |
| 408 |
oBlk.tail = oBlk.buf + bufSize; |
| 409 |
|
| 410 |
/* =================================================================== |
| 411 |
* Pass 2: External merge of all blocks using priority queue |
| 412 |
* =================================================================== */ |
| 413 |
|
| 414 |
do { |
| 415 |
/* Get next node in priority queue, read next record in corresponding |
| 416 |
* block, and send to output */ |
| 417 |
b = OOC_Sort_Pop(&pqueue); |
| 418 |
|
| 419 |
if (b >= 0) { |
| 420 |
/* Priority queue non-empty */ |
| 421 |
if (!(rec = OOC_Sort_Read(iBlk + b, recSize))) { |
| 422 |
/* Corresponding record should still be in the buffa, so EOF |
| 423 |
* should not happen */ |
| 424 |
fprintf(stderr, "OOC_Sort: unexpected EOF in block file\n"); |
| 425 |
return -1; |
| 426 |
} |
| 427 |
|
| 428 |
if (!OOC_Sort_Write(&oBlk, recSize, rec)) { |
| 429 |
fprintf(stderr, "OOC_Sort; error writing to output file %s\n", |
| 430 |
outFile); |
| 431 |
return -1; |
| 432 |
} |
| 433 |
|
| 434 |
/* Peek next record from same block and insert in priority queue */ |
| 435 |
if (rec = OOC_Sort_Peek(iBlk + b, recSize)) |
| 436 |
/* Buffa not exhausted */ |
| 437 |
if (OOC_Sort_Push(&pqueue, priority(rec), b) < 0) { |
| 438 |
fprintf(stderr, "OOC_Sort: failed priority queue insertion\n"); |
| 439 |
return -1; |
| 440 |
} |
| 441 |
} |
| 442 |
} while (b >= 0); |
| 443 |
|
| 444 |
/* Priority queue now empty; flush output buffa & close file */ |
| 445 |
oBlk.tail = oBlk.head; |
| 446 |
OOC_Sort_Write(&oBlk, 0, NULL); |
| 447 |
fclose(oBlk.file); |
| 448 |
|
| 449 |
for (b = 0; b < numBlk; b++) { |
| 450 |
fclose(iBlk [b].file); |
| 451 |
free(iBlk [b].buf); |
| 452 |
} |
| 453 |
|
| 454 |
free(iBlk); |
| 455 |
free(pqueue.node); |
| 456 |
|
| 457 |
return 0; |
| 458 |
} |
