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Restructured tags to better support xored-globals

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32-bit tag structure:
[---        32       ---]
[1|- 9 -|- 10 -|-- 12 --]
 ^   ^     ^       ^- entry length
 |   |     \--------- file id
 |   \--------------- tag type
 \------------------- valid

In this tag, the type decomposes into some more information:
[---      9      ---]
[1|- 2 -|- 3 -|- 3 -]
 ^   ^     ^     ^- struct
 |   |     \------- type
 |   \------------- scope
 \----------------- user

The change in this encoding is the addition of a global scope:
LFS_SCOPE_STRUCT = 0 00 xxx xxx
LFS_SCOPE_ENTRY  = 0 01 xxx xxx
LFS_SCOPE_DIR    = 0 10 xxx xxx
LFS_SCOPE_FS     = 0 11 xxx xxx
LFS_SCOPE_USER   = 1 xx xxx xxx
This commit is contained in:
Christopher Haster
2018-05-29 20:08:42 -05:00
parent e39f7e99d1
commit 3ffcedb95b
2 changed files with 117 additions and 106 deletions
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lfs.h
+27 -17
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@@ -96,30 +96,40 @@ enum lfs_error {
// File types
enum lfs_type {
// file types
LFS_TYPE_REG = 0x040,
LFS_TYPE_DIR = 0x050,
LFS_TYPE_REG = 0x008,
LFS_TYPE_DIR = 0x010,
LFS_TYPE_SUPERBLOCK = 0x038,
// internally used entry structures
LFS_STRUCT_CTZ = 0x001,
LFS_STRUCT_DIR = 0x002,
LFS_STRUCT_INLINE = 0x003,
LFS_STRUCT_NAME = 0x041,
LFS_STRUCT_DELETE = 0x047,
LFS_STRUCT_MOVE = 0x046, // TODO rm me
LFS_STRUCT_TAIL = 0x081,
LFS_STRUCT_CRC = 0x087,
LFS_STRUCT_IDELETE = 0x0c1,
// internally used types
LFS_TYPE_NAME = 0x010,
LFS_TYPE_MOVE = 0x080,
LFS_TYPE_DELETE = 0x020,
LFS_TYPE_SOFTTAIL = 0x081,
LFS_TYPE_HARDTAIL = 0x089,
LFS_TYPE_CRC = 0x087,
LFS_TYPE_IDELETE = 0x0c1,
LFS_TYPE_SUPERBLOCK = 0x030,
LFS_TYPE_IDELETE = 0x0b0,
LFS_TYPE_SOFTTAIL = 0x0c0,
LFS_TYPE_HARDTAIL = 0x0d0,
LFS_TYPE_CRC = 0x0e0,
// on disk structure
LFS_STRUCT_ATTR = 0x100,
LFS_STRUCT_INLINE = 0x000,
LFS_STRUCT_CTZ = 0x004,
LFS_STRUCT_DIR = 0x008,
// internally used scopes
LFS_SCOPE_STRUCT = 0x000,
LFS_SCOPE_ENTRY = 0x040,
LFS_SCOPE_DIR = 0x080,
LFS_SCOPE_FS = 0x0c0,
LFS_SCOPE_USER = 0x100,
// internal sources
LFS_FROM_REGION = 0x000,
LFS_FROM_DISK = 0x200,
LFS_FROM_MOVE = 0x001,
LFS_FROM_MOVE = 0x004,
};
// File open flags