1 #include "inc.h" 2 3 static struct dir_extent dir_extents[NR_DIR_EXTENT_RECORDS]; 4 5 struct dir_extent* alloc_extent(void) 6 { 7 /* Return a free extent from the pool. */ 8 int i; 9 struct dir_extent *extent; 10 11 for (i = 0; i < NR_DIR_EXTENT_RECORDS; i++) { 12 extent = &dir_extents[i]; 13 14 if (extent->in_use == 0) { 15 memset(extent, 0, sizeof(*extent)); 16 extent->in_use = 1; 17 18 return extent; 19 } 20 } 21 22 panic("No free extents in cache"); 23 } 24 25 void free_extent(struct dir_extent *e) 26 { 27 if (e == NULL) 28 return; 29 30 if (e->in_use == 0) 31 panic("Trying to free unused extent"); 32 33 free_extent(e->next); 34 e->in_use = 0; 35 } 36 37 struct buf* read_extent_block(struct dir_extent *e, size_t block) 38 { 39 size_t block_id = get_extent_absolute_block_id(e, block); 40 41 if (block_id == 0 || block_id >= v_pri.volume_space_size_l) 42 return NULL; 43 44 return lmfs_get_block(fs_dev, block_id, NORMAL); 45 } 46 47 size_t get_extent_absolute_block_id(struct dir_extent *e, size_t block) 48 { 49 size_t extent_offset = 0; 50 51 if (e == NULL) 52 return 0; 53 54 /* Retrieve the extent on which the block lies. */ 55 while(block > extent_offset + e->length) { 56 if (e->next == NULL) 57 return 0; 58 59 extent_offset += e->length; 60 e = e->next; 61 } 62 63 return e->location + block - extent_offset; 64 } 65 66 time_t date7_to_time_t(const u8_t *date) 67 { 68 /* This function converts from the ISO 9660 7-byte time format to a 69 * time_t. 70 */ 71 struct tm ltime; 72 signed char time_zone = (signed char)date[6]; 73 74 ltime.tm_year = date[0]; 75 ltime.tm_mon = date[1] - 1; 76 ltime.tm_mday = date[2]; 77 ltime.tm_hour = date[3]; 78 ltime.tm_min = date[4]; 79 ltime.tm_sec = date[5]; 80 ltime.tm_isdst = 0; 81 82 /* Offset from Greenwich Mean Time */ 83 if (time_zone >= -52 && time_zone <= 52) 84 ltime.tm_hour += time_zone; 85 86 return mktime(<ime); 87 } 88