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ur: adds ur_walk_fore - higher-ordered pre-order noun traversal

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This commit is contained in:
Joe Bryan 2020-08-10 12:56:54 -07:00
parent d0e5c658a9
commit 039ef019b9
2 changed files with 58 additions and 0 deletions
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7
pkg/urbit/include/ur/hashcons.h
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@ -163,3 +163,10 @@ ur_nvec_free(ur_nvec_t *v);
void
ur_nvec_init(ur_nvec_t *v, uint64_t size);
void
ur_walk_fore(ur_root_t *r,
ur_nref ref,
void *v,
void (*atom)(ur_root_t*, ur_nref, void*),
ur_bool_t (*cell)(ur_root_t*, ur_nref, void*));

51
pkg/urbit/ur/hashcons.c
View File

@ -821,3 +821,54 @@ ur_nvec_init(ur_nvec_t *v, uint64_t size)
v->fill = 0;
v->refs = calloc(size, sizeof(ur_nref));
}
void
ur_walk_fore(ur_root_t *r,
ur_nref ref,
void *v,
void (*atom)(ur_root_t*, ur_nref, void*),
ur_bool_t (*cell)(ur_root_t*, ur_nref, void*))
{
uint64_t prev = 89, size = 144, fill = 0;
ur_nref *top, *don;
don = malloc(size * sizeof(*don));
top = don + ++fill;
*top = ref;
while ( top != don ) {
// visit atom, pop stack
//
if ( !ur_deep(ref) ) {
atom(r, ref, v);
top--; fill--;
}
// visit cell, pop stack if false
//
else if ( !cell(r, ref, v) ) {
top--; fill--;
}
// push the tail, continue into the head
//
else {
*top = ur_tail(r, ref);
// reallocate "stack" if full
//
if ( size == fill ) {
uint64_t next = prev + size;
don = realloc(don, next * sizeof(*don));
top = don + fill;
prev = size;
size = next;
}
top++; fill++;
*top = ur_head(r, ref);
}
ref = *top;
}
free(don);
}