Added lfsr_rid/bid/mid/did_t types, tried using types more consistently

Adopted lfsr_rid/bid/mid/did_t where appropriate. This includes using
lfsr_rid_t for tag/rbyd weights. Although I am using lfsr_srid_t for
rbyd weights now, since it both captures the use of the sign bit and
reduces the number of casts a bit in the code.

I learned recently Zig has any-bit integers (e.g. uint31_t), and I'm
realizing how nice it would be to have those in this codebase.

Also tried to use lfs_size_t/lfs_off_t more correctly. In Linux/BSD,
only off_t is used for file-size-related operations and is usually much
larger than size_t. These were used interchangably in littlefs and their
original meaning kind of fell by the wayside. Getting their use right
will be important if littlefs ever supports different integer widths.

lfs.h

@@ -37,15 +37,27 @@ extern "C"
 
 // Type definitions
 typedef uint32_t lfs_size_t;
-typedef uint32_t lfs_off_t;
-
 typedef int32_t  lfs_ssize_t;
+
+typedef uint32_t lfs_off_t;
 typedef int32_t  lfs_soff_t;
 
 typedef uint32_t lfs_block_t;
 
+typedef uint32_t lfsr_rid_t;
+typedef int32_t  lfsr_srid_t;
+
 typedef uint16_t lfsr_tag_t;
-typedef int16_t lfsr_stag_t;
+typedef int16_t  lfsr_stag_t;
+
+typedef uint32_t lfsr_bid_t;
+typedef int32_t  lfsr_sbid_t;
+
+typedef uint32_t lfsr_mid_t;
+typedef int32_t  lfsr_smid_t;
+
+typedef uint32_t lfsr_did_t;
+typedef int32_t  lfsr_sdid_t;
 
 // Maximum name size in bytes, may be redefined to reduce the size of the
 // info struct. Limited to <= 1022. Stored in superblock and must be
@@ -324,7 +336,7 @@ struct lfs_file_config {
 /// internal littlefs data structures ///
 typedef struct lfs_cache {
     lfs_block_t block;
-    lfs_off_t off;
+    lfs_size_t off;
     lfs_size_t size;
     uint8_t *buffer;
 } lfs_cache_t;
@@ -332,12 +344,12 @@ typedef struct lfs_cache {
 // TODO do we get ram savings with a lfsr_rorbyd_t substruct? need to measure
 typedef struct lfsr_rbyd {
     // note this lines up with weight in lfsr_btree_t
-    lfs_size_t weight;
+    lfsr_srid_t weight;
     // eoff=0, trunk=0  => not yet committed
     // eoff=0, trunk>0  => not yet fetched
     // eoff>=block_size => rbyd not erased/needs compaction
-    lfs_off_t trunk;
-    lfs_off_t eoff;
+    lfs_size_t trunk;
+    lfs_size_t eoff;
     uint32_t cksum;
     // note this lines up with arrays of redundant blocks in lfsr_mdir_t
     lfs_block_t block;
@@ -356,11 +368,11 @@ typedef struct lfsr_btree {
     union {
         // weight is common to both representations and its sign-bit indicates
         // if the btree is inlined
-        lfs_size_t weight;
+        lfsr_sbid_t weight;
         struct {
-            lfs_size_t weight;
+            lfsr_sbid_t weight;
             lfsr_tag_t tag;
-            uint16_t size;
+            uint8_t size;
             uint8_t buf[LFSR_BTREE_INLINESIZE];
         } i;
         struct {
@@ -370,12 +382,12 @@ typedef struct lfsr_btree {
 } lfsr_btree_t;
 
 typedef struct lfsr_mdir {
-    lfs_ssize_t mid;
+    lfsr_smid_t mid;
     union {
         // here we make sure to line up our block array so it overlaps with
         // the block stored as the first entry in the rbyd
         struct {
-            lfs_size_t weight;
+            lfsr_srid_t weight;
             lfs_off_t trunk;
             lfs_off_t eoff;
             uint32_t cksum;
@@ -401,7 +413,7 @@ typedef struct lfsr_openedmdir {
 #define LFSR_GRM_DSIZE (1+5+5+5+5)
 
 typedef struct lfsr_grm {
-    lfs_ssize_t rms[2];
+    lfsr_smid_t rms[2];
 } lfsr_grm_t;
 
 
@@ -429,9 +441,9 @@ typedef struct lfs_dir {
 
 typedef struct lfsr_dir {
     lfsr_openedmdir_t m;
-    lfs_size_t did;
-    lfs_ssize_t bookmark;
-    lfs_off_t pos;
+    lfsr_did_t did;
+    lfsr_smid_t bookmark;
+    lfs_soff_t pos;
 } lfsr_dir_t;
 
 // littlefs file type
@@ -751,7 +763,7 @@ int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info);
 //
 // Returns a negative error code on failure.
 int lfs_dir_seek(lfs_t *lfs, lfs_dir_t *dir, lfs_off_t off);
-int lfsr_dir_seek(lfs_t *lfs, lfsr_dir_t *dir, lfs_off_t off);
+int lfsr_dir_seek(lfs_t *lfs, lfsr_dir_t *dir, lfs_soff_t off);
 
 // Return the position of the directory
 //

tests/test_btree.toml

@@ -3192,7 +3192,7 @@ code = '''
     lfsr_btree_t btree = LFSR_BTREE_NULL;
     lfsr_btree_push(&lfs, &btree, 0, LFSR_TAG_INLINED, 1,
             LFSR_DATA("0", 1)) => 0;
-    lfsr_btree_split(&lfs, &btree, 0, LFSR_DATA_NAME(0*DID, "aab", 3),
+    lfsr_btree_split(&lfs, &btree, 0, LFSR_DATA_NAME(0, "aab", 3),
             LFSR_TAG_INLINED, 1, LFSR_DATA("0", 1),
             LFSR_TAG_INLINED, 1, LFSR_DATA("1", 1)) => 0;
     printf("btree: w%d 0x%x.%x\n",

tests/test_mtree.toml

@@ -1485,8 +1485,7 @@ code = '''
         mdir.mid = (mdir.mid & lfsr_mbidmask(&lfs))
                 | (mdir.mid % (mdir.u.m.weight+1));
         // choose to create or delete
-        uint8_t op = ((lfs_size_t)(mdir.mid & lfsr_mridmask(&lfs))
-                    == mdir.u.m.weight
+        uint8_t op = ((mdir.mid & lfsr_mridmask(&lfs)) == mdir.u.m.weight
                 ? 0
                 : TEST_PRNG(&prng) % 2);
 
@@ -2569,8 +2568,7 @@ code = '''
         mdir.mid = (mdir.mid & lfsr_mbidmask(&lfs))
                 | (mdir.mid % (mdir.u.m.weight+1));
         // choose to create or delete
-        uint8_t op = ((lfs_size_t)(mdir.mid & lfsr_mridmask(&lfs))
-                    == mdir.u.m.weight
+        uint8_t op = ((mdir.mid & lfsr_mridmask(&lfs)) == mdir.u.m.weight
                 ? 0
                 : TEST_PRNG(&prng) % 3);