ref: 658dd280c40c5a6edb110e1170013e8479fe2bd0
dir: /lib/std/pathjoin.myr/
use "alloc"
use "extremum"
use "strjoin"
use "strsplit"
use "sleq"
use "sljoin"
use "sldup"
use "slcp"
use "die"
use "fmt"
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 in the code.
*/
for i = 0; i < comps.len; i++
if sleq(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 !sleq(comps[i], "..")
continue
;;
for del = 1; del <= i; del++
if comps[i - del].len > 0 && !sleq(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 && sleq(p[:1], "/")
for i = 0; i < comps.len; i++
if !sleq(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
}