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Restructured lfsr_btree_traverse a bit to be simpler

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- Rely on rbyd lookup ENOENT now that that is cheap

- Adopt internal traverse_ function with shrub bool to indicate if root
  should be included, similar to btree_commit_

Code changes:

            code          stack
  before:  33956           2944
  after:   33976 (+0.1%)   2944 (+0.0%)
This commit is contained in:
Christopher Haster
2024-01-19 16:05:46 -06:00
parent fdfa7b5908
commit 9978b46a0c
1 changed files with 39 additions and 39 deletions
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lfs.c
+39 -39
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@@ -4564,41 +4564,40 @@ typedef struct lfsr_btraversal {
.branch.trunk=0, \
.branch.weight=0})
static int lfsr_btree_traverse(lfs_t *lfs, const lfsr_btree_t *btree,
static int lfsr_btree_traverse_(lfs_t *lfs,
const lfsr_btree_t *btree, bool shrub,
lfsr_btraversal_t *btraversal,
lfsr_bid_t *bid_, lfsr_tinfo_t *tinfo_) {
while (true) {
// in range?
if (btraversal->bid >= (lfsr_bid_t)btree->weight
// make sure we traverse the root even if weight=0
&& (btraversal->branch.trunk != 0
// unless we don't even have a root yet
|| btree->trunk == 0)) {
return LFS_ERR_NOENT;
}
// explicitly traverse the root even if weight=0
if (btraversal->branch.trunk == 0
// unless we don't even have a root yet
&& btree->trunk != 0
// or are a shrub
&& !shrub) {
btraversal->rid = btraversal->bid;
btraversal->branch = *btree;
// restart from the root
if (btraversal->rid >= btraversal->branch.weight) {
btraversal->rid = btraversal->bid;
btraversal->branch = *btree;
// traverse the root
if (btraversal->rid == 0) {
if (bid_) {
*bid_ = btree->weight-1;
}
if (tinfo_) {
tinfo_->tag = LFSR_TAG_BRANCH;
tinfo_->u.rbyd = btraversal->branch;
}
return 0;
// traverse the root
if (btraversal->rid == 0) {
if (bid_) {
*bid_ = btree->weight-1;
}
// continue, mostly for range check
continue;
if (tinfo_) {
tinfo_->tag = LFSR_TAG_BRANCH;
tinfo_->u.rbyd = btraversal->branch;
}
return 0;
}
}
// descend down the tree
// need to restart from the root?
if (btraversal->rid >= btraversal->branch.weight) {
btraversal->rid = btraversal->bid;
btraversal->branch = *btree;
}
// descend down the tree
while (true) {
lfsr_srid_t rid__;
lfsr_tag_t tag__;
lfsr_rid_t weight__;
@@ -4607,7 +4606,6 @@ static int lfsr_btree_traverse(lfs_t *lfs, const lfsr_btree_t *btree,
btraversal->rid, 0,
&rid__, &tag__, &weight__, &data__);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
@@ -4651,7 +4649,7 @@ static int lfsr_btree_traverse(lfs_t *lfs, const lfsr_btree_t *btree,
} else {
// move on to the next rid
//
// note the effectively traverses a full leaf without redoing
// note this effectively traverses a full leaf without redoing
// the btree walk
lfsr_bid_t bid__ = btraversal->bid + (rid__ - btraversal->rid);
btraversal->bid = bid__ + 1;
@@ -4669,6 +4667,14 @@ static int lfsr_btree_traverse(lfs_t *lfs, const lfsr_btree_t *btree,
}
}
static int lfsr_btree_traverse(lfs_t *lfs, const lfsr_btree_t *btree,
lfsr_btraversal_t *btraversal,
lfsr_bid_t *bid_, lfsr_tinfo_t *tinfo_) {
return lfsr_btree_traverse_(lfs, btree, false,
btraversal,
bid_, tinfo_);
}
/// shrub/sprout things ///
@@ -9569,15 +9575,9 @@ static int lfsr_file_traverse(lfs_t *lfs, const lfsr_file_t *file,
// bshrub/btree?
} else if (lfsr_ftree_isbshruborbtree(&file->ftree)) {
// prevent bshrub root from being traversed, since this is
// just our mdir
if (lfsr_ftree_isbshrub(&file->m.mdir, &file->ftree)
&& btraversal->branch.trunk == 0) {
btraversal->branch = *lfsr_shrub_rbyd(&file->ftree.u.bshrub);
}
int err = lfsr_btree_traverse(lfs,
int err = lfsr_btree_traverse_(lfs,
lfsr_shrub_rbyd(&file->ftree.u.bshrub),
lfsr_ftree_isbshrub(&file->m.mdir, &file->ftree),
btraversal,
bid_, tinfo_);
if (err) {