Changeset 0153c87 in mainline for uspace/dist/src/bithenge/fat.bh

Timestamp:

2012-08-10T20:09:36Z (12 years ago)

Author:

Sean Bartell <wingedtachikoma@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

6be4142

Parents:

c9797067

Message:

Bithenge: more FAT, operators, and fixes

File:

• uspace/dist/src/bithenge/fat.bh (modified) (2 diffs)

uspace/dist/src/bithenge/fat.bh

@@ -32 +32 @@
 transform u32 = uint32le;
 
+transform fat_dir_entry(disk) = struct {
+        .filename <- known_length(8);
+        .extension <- known_length(3);
+        .attrs <- u8;
+        .flags <- u8;
+        .ctime_fine <- u8;
+        .ctime <- u16;
+        .cdate <- u16;
+        .adate <- u16;
+        .permissions <- u16;
+        .mtime <- u16;
+        .mdate <- u16;
+        .start <- u16;
+        .size <- u32;
+};
+
+transform fat_table(bits, num_clusters) = switch (bits) {
+        12: partial {repeat(num_clusters) { uint_le(12) }} <- bits_le;
+        16: partial {repeat(num_clusters) { u16 }};
+        32: partial {repeat(num_clusters) { u32 }};
+};
+
 transform fat_super(disk) = struct {
         .jump_instruction <- known_length(3);
@@ -63 +85 @@
         };
 
+        .first_root_sector <- (.num_reserved_sectors + .num_fats * .sectors_per_fat);
+        .first_data_sector <- (.first_root_sector +
+            (.num_root_entries * 32 + .bytes_per_sector - 1) //
+            .bytes_per_sector);
+        .num_clusters <- (2 + (.num_sectors - .first_data_sector) // .sectors_per_cluster);
+        .bits <- if (.num_clusters < 4085) { (12) }
+            else { if (.num_clusters < 65525) { (16) } else { (32) } };
+
+        .fats <- partial(.num_reserved_sectors * .bytes_per_sector) {
+                repeat(.num_fats) {
+                        fat_table(.bits, .num_clusters) <-
+                                known_length(.sectors_per_fat * .bytes_per_sector)
+                }
+        } <- (disk);
+
+        .root <- partial(.first_root_sector * .bytes_per_sector) {
+                repeat(.num_root_entries) { fat_dir_entry(disk) } } <- (disk);
+
         .boot_signature <- (disk[510,2]); # b"\x55\xaa"; TODO: what if .bytes_per_sector < 512?
 };