ref: 3853fa79b7d297f4bd3aaf318a147a95dd088bc9
dir: /lib/std/pathjoin.myr/
use "alloc"
use "die"
use "extremum"
use "fmt"
use "sleq"
use "slcp"
use "sldup"
use "sljoin"
use "strjoin"
use "strsplit"
use "traits"
pkg std =
const pathcat : (a : byte[:], b : byte[:] -> byte[:])
const pathjoin : (p : byte[:][:] -> byte[:])
const pathnorm : (p : byte[:] -> byte[:])
;;
const pathcat = {a, b
-> pathjoin([a, b][:])
}
const pathjoin = {l
var p, i, q
for i = 0; i < l.len; i++
if l[i].len != 0
break
;;
;;
p = strjoin(l[i:], "/")
q = pathnorm(p)
slfree(p)
-> q
}
const pathnorm = {p
var comps
var i, del, dst
var s, ret
comps = strsplit(p, "/")
/*
"." is a no-op component, so we drop it. In order
to drop a component, we set it to the empty string,
and remove it later on.
*/
for i = 0; i < comps.len; i++
if eq(comps[i], ".")
comps[i] = ""
;;
;;
/*
then, resolve '..' by cancelling out previous components. Scan
backwards in the component list for the first real component,
and delete both it and the '..' that lead to it.
Leave in extra '..' components, so that, eg, ../foo doesn't
get mangled.
*/
for i = 0; i < comps.len; i++
if !eq(comps[i], "..")
continue
;;
for del = 1; del <= i; del++
if comps[i - del].len > 0 && !eq(comps[i-del], "..")
comps[i - del] = ""
comps[i] = ""
break
;;
;;
;;
/* clear out the path nodes we decided to drop */
dst = 0
for i = 0; i < comps.len; i++
if comps[i].len > 0
comps[dst++] = comps[i]
;;
;;
comps = comps[:dst]
/*
and reassemble. If we have an absolute path,
make it absolute. If we have an empty path, return
".". Otherwise, just return the path.
*/
if p.len > 0 && eq(p[:1], "/")
for i = 0; i < comps.len; i++
if !eq(comps[i], "..")
break
;;
;;
s = strjoin(comps[i:], "/")
ret = fmt("/{}", s)
slfree(s)
elif comps.len == 0
ret = sldup(".")
else
ret = strjoin(comps, "/")
;;
slfree(comps)
-> ret
}