ref: 2b755a0e6bffb0f75f9b0f1433cfe55bd7499606
dir: /lib/regex/interp.myr/
use std
use "types"
pkg regex =
const exec : (re : regex#, str : byte[:] -> std.option(byte[:][:]))
const matchfree : (pat : byte[:][:] -> void)
/*
FIXME: implement. This should scan for a possible start char in the
regex and use that to optimize.
const search : (re : regex#, str : byte[:] -> std.option(byte[:][:]))
*/
;;
/* Ugly: for performance. std.option() should be used instead when unions get faster. */
const Zthr = 0 castto(rethread#)
const exec = {re, str
var thr
var m
re.str = str
re.strp = 0
thr = run(re)
if thr != Zthr
m = getmatches(re, thr)
thrfree(re, thr)
cleanup(re)
-> `std.Some m
else
cleanup(re)
-> `std.None
;;
}
const cleanup = {re
var thr, next
for thr = re.runq; thr != Zthr; thr = next
next = thr.next
thrfree(re, thr)
;;
for thr = re.expired; thr != Zthr; thr = next
next = thr.next
thrfree(re, thr)
;;
}
const matchfree = {m
std.slfree(m)
}
const getmatches = {re, thr
var ret
ret = std.slalloc(re.nmatch)
for var i = 0; i < re.nmatch; i++
if thr.mstart[i] != -1 && thr.mend[i] != -1
ret[i] = re.str[thr.mstart[i]:thr.mend[i]]
else
ret[i] = [][:]
;;
;;
-> ret
}
/* returns a matching thread, or Zthr if no threads matched */
const run = {re
var ip
var consumed
var thr
var states
states = std.mkbs()
re.runq = mkthread(re, 0)
re.runq.mstart = std.slalloc(re.nmatch)
re.runq.mend = std.slalloc(re.nmatch)
for var i = 0; i < re.nmatch; i++
re.runq.mstart[i] = -1
re.runq.mend[i] = -1
;;
while re.nthr > 0
while re.runq != Zthr
/* set up the next thread */
thr = re.runq
re.runq = thr.next
trace(re, thr, "\nrunning tid={}, ip={}, s[{}]={}\n", thr.tid, thr.ip, re.strp, std.decode(re.str[re.strp:]))
ip = thr.ip
consumed = step(re, thr, -1)
while !consumed
consumed = step(re, thr, ip)
;;
if std.bshas(states, thr.ip)
die(re, thr, "there can be only one")
;;
if thr.dead
thrfree(re, thr)
elif thr.matched && re.strp == re.str.len
std.bsfree(states)
-> thr
elif !thr.matched
std.bsput(states, thr.ip)
if re.expired == Zthr
re.expired = thr
;;
if re.expiredtail != Zthr
re.expiredtail.next = thr
;;
re.expiredtail = thr
thr.next = Zthr
;;
;;
std.bsclear(states)
trace(re, thr, "switch\n")
re.runq = re.expired
re.expired = Zthr
re.expiredtail = Zthr
re.strp++
;;
std.bsfree(states)
-> Zthr
}
/*
Steps forward one instruction. Returns true if a byte of input was
consumed, false otherwise.
*/
const step = {re, thr, curip
var str
var mstart
var mend
str = re.str
match re.prog[thr.ip]
/* Char matching. Consume exactly one byte from the string. */
| `Ibyte b:
trace(re, thr, "\t{}:\tByte {} ({})\n", thr.ip, b, b castto(char))
if !within(re, str)
die(re, thr, "end of string")
elif b != str[re.strp]
die(re, thr, "not right char")
else
thr.ip++
trace(re, thr, "\t\tmatched {} with {}\n", b, str[re.strp])
;;
| `Irange (start, end):
trace(re, thr, "\t{}:\tRange ({}, {}) /* {} - {} */\n", thr.ip, start, end, start castto(char), end castto(char))
if !within(re, str) || start > str[re.strp] || end < str[re.strp]
die(re, thr, "bad range")
else
thr.ip++
;;
/*
Non-consuming. All of these return false, and expect step to be
called again until exactly one byte is consumed from the string.
*/
| `Ibol:
trace(re, thr, "\t{}:\tBol\n", thr.ip)
if re.strp == 0 || str[re.strp - 1] == '\n' castto(byte)
thr.ip++
-> false
else
die(re, thr, "not beginning of line")
;;
| `Ieol:
trace(re, thr, "\t{}:\tEol\n", thr.ip)
if re.strp == str.len || str[re.strp] == '\n' castto(byte)
thr.ip++
-> false
else
die(re, thr, "not end of line")
;;
/* check for word characters */
| `Ibow:
trace(re, thr, "\t{}:\tBow\n", thr.ip)
if iswordchar(str[re.strp:]) && (re.strp == 0 || !iswordchar(prevchar(str, re.strp)))
thr.ip++
-> false
else
die(re, thr, "not beginning of word")
;;
| `Ieow:
trace(re, thr, "\t{}:\tEow\n", thr.ip)
if re.strp == str.len && iswordchar(prevchar(str, re.strp))
thr.ip++
-> false
elif re.strp > 0 && !iswordchar(str[re.strp:]) && iswordchar(prevchar(str, re.strp))
thr.ip++
-> false
else
die(re, thr, "not end of word")
;;
| `Ilbra m:
trace(re, thr, "\t{}:\tLbra {}\n", thr.ip, m)
trace(re, thr, "\t\tmatch start = {}\n", re.strp)
thr.mstart[m] = re.strp
thr.ip++
-> false
| `Irbra m:
trace(re, thr, "\t{}:\tRbra {}\n", thr.ip, m)
thr.mend[m] = re.strp
thr.ip++
-> false
| `Ifork (lip, rip):
trace(re, thr, "\t{}:\tFork ({}, {})\n", thr.ip, lip, rip)
mstart = std.sldup(thr.mstart)
mend = std.sldup(thr.mend)
fork(re, thr, rip, curip, mstart, mend)
thr.ip = lip
-> false
| `Ijmp ip:
trace(re, thr, "\t{}:\tJmp {}\n", thr.ip, ip)
thr.ip = ip
-> false
| `Imatch id:
trace(re, thr, "\t{}:\tMatch\n", thr.ip)
finish(re, thr)
-> true
;;
-> true
}
const fork = {re, thr, ip, curip, mstart, mend
var thr
if ip == curip /* loop detection */
-> void
;;
thr = mkthread(re, ip)
thr.next = re.runq
thr.mstart = mstart
thr.mend = mend
re.runq = thr
}
const die = {re, thr, msg
/*
we can have die called on a thread
multiple times, eg, if it has a bad
range *and* end in a state that another
thread is in. We should only decrement
the number of threads for that once.
*/
trace(re, thr, "\t\tdie {}: {}\n", thr.tid, msg)
if !thr.dead
re.nthr--
;;
thr.dead = true
}
const finish = {re, thr
trace(re, thr, "finish {}\n", thr.tid)
thr.matched = true
re.nthr--
}
var nexttid = 0
const mkthread = {re, ip
var thr : rethread#
thr = std.alloc()
thr.next = Zthr
thr.ip = ip
thr.tid = nexttid++
thr.dead = false
thr.matched = false
thr.mstart = [][:]
thr.mend = [][:]
re.nthr++
-> thr
}
const thrfree = {re, thr
trace(re, thr, "\t\tcleanup {}\n", thr.tid)
std.slfree(thr.mstart)
std.slfree(thr.mend)
std.free(thr)
}
const within = {re, str
-> re.strp < str.len
}
const trace : (re : regex#, thr : rethread#, msg : byte[:], args : ... -> void) = {re, thr, msg, args
var ap
if re.debug
ap = std.vastart(&args)
std.putv(msg, &ap)
;;
}
/* must be called with i >= 1 */
const prevchar = {s, i
std.assert(i != 0, "prevchar must be called with i >= 1\n")
i--
while i != 0 && s[i] >= 0x80
i--
;;
-> s[i:]
}
const iswordchar = {s
var c
c = std.decode(s)
-> std.isalpha(c) || std.isdigit(c) || c == '_'
}