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comparison lib/lib.c @ 310:8b8116214b1c

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Roberto Foglietta pointed out that readall() needs fdlength() to restore the original position before exiting.
author Rob Landley <rob@landley.net>
date Fri, 18 Jul 2008 05:43:44 -0500
parents 79a61cd58596
children 962bbf7341f8
comparison
equal deleted inserted replaced
309:79a61cd58596 310:8b8116214b1c
472 } 472 }
473 473
474 // Return how long the file at fd is, if there's any way to determine it. 474 // Return how long the file at fd is, if there's any way to determine it.
475 off_t fdlength(int fd) 475 off_t fdlength(int fd)
476 { 476 {
477 off_t bottom = 0, top = 0, pos; 477 off_t bottom = 0, top = 0, pos, old;
478 int size; 478 int size;
479 479
480 // If the ioctl works for this, return it. 480 // If the ioctl works for this, return it.
481 481
482 if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512L; 482 if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512L;
483 483
484 // If not, do a binary search for the last location we can read. (Some 484 // If not, do a binary search for the last location we can read. (Some
485 // block devices don't do BLKGETSIZE right.) This should probably have 485 // block devices don't do BLKGETSIZE right.) This should probably have
486 // a CONFIG option... 486 // a CONFIG option...
487 487
488 old = lseek(fd, 0, SEEK_CUR);
488 do { 489 do {
489 char temp; 490 char temp;
490 491
491 pos = bottom + (top - bottom) / 2; 492 pos = bottom + (top - bottom) / 2;
492 493
503 if (!top) return 0; 504 if (!top) return 0;
504 bottom = top/2; 505 bottom = top/2;
505 } else top = pos; 506 } else top = pos;
506 } 507 }
507 } while (bottom + 1 != top); 508 } while (bottom + 1 != top);
509
510 lseek(fd, old, SEEK_SET);
508 511
509 return pos + 1; 512 return pos + 1;
510 } 513 }
511 514
512 // This can return null (meaning file not found). It just won't return null 515 // This can return null (meaning file not found). It just won't return null