ref: 066812db79f10a3cdee5268ad7214bacb44d2eef
dir: /lib/regex/interp.myr/
use std
use "types"
pkg regex =
/* regex execution */
const exec : (re : regex#, str : byte[:] -> std.option(byte[:][:]))
const search : (re : regex#, str : byte[:] -> std.option(byte[:][:]))
/* regex execution returning indexes */
const iexec : (re : regex#, str : byte[:] -> std.option((std.size, std.size)[:]))
const isearch : (re : regex#, str : byte[:] -> std.option((std.size, std.size)[:]))
/* substitution */
const sub : (re : regex#, str : byte[:], subst : byte[:][:] -> std.option(byte[:]))
const sbsub : (sb : std.strbuf#, re : regex#, str : byte[:], subst : byte[:][:] -> bool)
const suball : (re : regex#, str : byte[:], subst : byte[:][:] -> byte[:])
const sbsuball : (sb : std.strbuf#, re : regex#, str : byte[:], subst : byte[:][:] -> void)
const matchfree : (pat : byte[:][:] -> void)
;;
/* Ugly: for performance. std.option() should be used instead when unions get faster. */
const Zthr = (0 : rethread#)
const Maxfree = 128
const matchfree = {m
std.slfree(m)
}
const exec = {re, str
-> getmatches(re, run(re, str, 0, true))
}
const iexec = {re, str
-> getidxmatches(re, run(re, str, 0, true))
}
const search = {re, str
var thr = Zthr
for var i = 0; i < str.len; i++
thr = run(re, str[i:], 0, false)
if thr != Zthr
break
;;
;;
-> getmatches(re, thr)
}
const isearch = {re, str
var thr = Zthr
for var i = 0; i < str.len; i++
thr = run(re, str[i:], 0, false)
if thr != Zthr
break
;;
;;
-> getidxmatches(re, thr)
}
const sub = {re, str, subst
var sb
sb = std.mksb()
if sbsub(sb, re, str, subst)
-> `std.Some std.sbfin(sb)
;;
-> `std.None
}
const sbsub = {sb, re, str, subst
std.assert(re.nmatch == subst.len + 1, "substitution length does not match capture count")
-> dosubst(sb, re, run(re, str, 0, true), str, subst)
}
const suball = {re, str, subst
var sb
sb = std.mksb()
sbsuball(sb, re, str, subst)
-> std.sbfin(sb)
}
const sbsuball = {sb, re, str, subst
var thr, len, i
std.assert(re.nmatch == subst.len + 1, "substitution length does not match capture count")
i = 0
while i < str.len
thr = run(re, str[i:], 0, false)
if thr == Zthr
std.sbputb(sb, str[i])
i++
else
len = thr.mgroup[0][1]
dosubst(sb, re, thr, str[i:len + i], subst)
i += len
;;
cleanup(re, thr)
;;
}
const dosubst = {sb, re, thr, str, subst
var off
if thr == Zthr
-> false
;;
off = 0
for var i = 1; i < re.nmatch; i++
if thr.mgroup[i][0] != -1 && thr.mgroup[i][1] != -1
std.sbputs(sb, str[off:thr.mgroup[i][0]])
std.sbputs(sb, subst[i - 1])
off = thr.mgroup[i][1]
;;
;;
std.sbputs(sb, str[off:])
-> true
}
const cleanup = {re, result
lfree(re.runq)
lfree(re.expired)
lfree(re.free)
std.free(result)
re.runq = Zthr
re.expired = Zthr
re.free = Zthr
re.nfree = 0
re.nexttid = 0
re.nthr = 0
}
const lfree = {thr
for var next = thr; thr != Zthr; thr = next
next = thr.next
std.free(thr)
;;
}
const getmatches = {re, thr
var ret, i
if thr == Zthr
-> `std.None
;;
i = 0
ret = std.slalloc(re.nmatch)
for [lo, hi] : thr.mgroup[:re.nmatch]
if lo != -1 && hi != -1
ret[i] = re.str[lo : hi]
;;
i++
;;
cleanup(re, thr)
-> `std.Some ret
}
const getidxmatches = {re, thr
var ret
if thr == Zthr
-> `std.None
;;
ret = std.slalloc(re.nmatch)
for var i = 0; i < re.nmatch; i++
ret[i] = (thr.mgroup[i][0], thr.mgroup[i][1])
;;
cleanup(re, thr)
-> `std.Some ret
}
/* returns a matching thread, or Zthr if no threads matched */
const run = {re, str, idx, wholestr
var bestmatch
var consumed
var states
var thr
var ip
re.str = str
re.strp = 0
bestmatch = Zthr
states = std.mkbs()
re.runq = mkthread(re, 0)
if re.debug
/* The last run could have left things here, since we need this info after the run */
for bs : re.traces
std.bsfree(bs)
;;
std.slfree(re.traces)
re.traces = [][:]
std.slpush(&re.traces, std.mkbs())
;;
for var i = 0; i < re.nmatch; i++
re.runq.mgroup[i][0] = -1
re.runq.mgroup[i][1] = -1
;;
while re.nthr > 0
while re.runq != Zthr
if re.trace
std.put("switch\n")
;;
/* set up the next thread */
thr = re.runq
re.runq = thr.next
ip = thr.ip
consumed = step(re, thr, -1)
while !consumed
consumed = step(re, thr, ip)
;;
if std.bshas(states, thr.ip)
die(re, thr)
;;
if thr.dead
thrfree(re, thr)
elif thr.matched
if bestmatch != Zthr
thrfree(re, bestmatch)
;;
if re.strp == re.str.len
bestmatch = thr
goto done
elif !wholestr
bestmatch = thr
else
thrfree(re, 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)
re.runq = re.expired
re.expired = Zthr
re.expiredtail = Zthr
re.strp++
;;
:done
std.bsfree(states)
-> bestmatch
}
/*
Steps forward one instruction. Returns true if a byte of input was
consumed, false otherwise.
*/
const step = {re, thr, curip
var str, nthr, inst
str = re.str
inst = re.code[thr.ip]
if re.trace
itrace(re, thr, re.prog[thr.ip])
;;
if re.debug
std.bsput(re.traces[thr.tid], thr.ip)
;;
match inst & 0xf
/* Char matching. Consume exactly one byte from the string. */
| OpRange:
var lo = (inst >> 4 : byte)
var hi = (inst >> 16 : byte)
if !within(re, str) || lo > str[re.strp] || hi < str[re.strp]
die(re, thr)
else
thr.ip++
;;
| OpByte:
var b = (inst >> 4 : byte)
if !within(re, str)
die(re, thr)
elif b != str[re.strp]
die(re, thr)
else
thr.ip++
;;
| OpFork:
var lip = ((inst >> 4) & 0x3fffffff : std.size)
var rip = ((inst >> 34) & 0x3fffffff : std.size)
if rip != curip
nthr = mkthread(re, rip)
nthr.next = re.runq
nthr.mgroup = thr.mgroup
re.runq = nthr
;;
if re.debug
std.slpush(&re.traces, std.bsdup(re.traces[thr.tid]))
;;
thr.ip = lip
-> false
/*
Non-consuming. All of these return false, and expect step to be
called again until exactly one byte is consumed from the string.
*/
| OpJmp:
var ip = (inst >> 4 : std.size)
thr.ip = ip
-> false
| OpMatch:
var id = (inst >> 4 : std.size)
re.lastthr = thr.tid
finish(re, thr)
-> true
| OpLbra:
var m = (inst >> 4 : std.size)
thr.mgroup[m][0] = re.strp
thr.ip++
-> false
| OpRbra:
var m = (inst >> 4 : std.size)
thr.mgroup[m][1] = re.strp
thr.ip++
-> false
| OpBol:
if re.strp == 0 || str[re.strp - 1] == ('\n' : byte)
thr.ip++
-> false
else
die(re, thr)
;;
| OpEol:
if re.strp == str.len || str[re.strp] == ('\n' : byte)
thr.ip++
-> false
else
die(re, thr)
;;
/* check for word characters */
| OpBow:
if iswordchar(str[re.strp:]) && (re.strp == 0 || !iswordchar(prevchar(str, re.strp)))
thr.ip++
-> false
else
die(re, thr)
;;
| OpEow:
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)
;;
| _:
std.die("corrupt regex bytecode")
;;
-> true
}
const die = {re, thr
/*
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.
*/
if !thr.dead
re.nthr--
;;
re.lastip = thr.ip
re.lastthr = thr.tid
thr.dead = true
}
const finish = {re, thr
thr.matched = true
re.nthr--
}
const mkthread = {re, ip
var thr : rethread#
if re.free != Zthr
thr = re.free
re.free = thr.next
re.nfree--
else
thr = std.alloc()
;;
thr.next = Zthr
thr.ip = ip
thr.tid = re.nexttid++
thr.dead = false
thr.matched = false
re.nthr++
-> thr
}
const thrfree = {re, thr
if re.nfree >= Maxfree
std.free(thr)
else
thr.next = re.free
re.free = thr
re.nfree++
;;
}
const within = {re, str
-> re.strp < str.len
}
const itrace = {re, thr, inst
match inst
| `Ibyte b: std.put("\t{}.{}:\tByte ({})\n", thr.tid, thr.ip, thr.tid, thr.ip, b)
| `Irange (lo, hi): std.put("\t{}.{}:\tRange {}, {}\n", thr.tid, thr.ip, lo, hi)
| `Ilbra m: std.put("\t{}.{}:\tLbra {}\n", thr.tid, thr.ip, m)
| `Irbra m: std.put("\t{}.{}:\tRbra {}\n", thr.tid, thr.ip, m)
/* anchors */
| `Ibol: std.put("\t{}.{}:\tBol\n", thr.tid, thr.ip)
| `Ieol: std.put("\t{}.{}:\tEol\n", thr.tid, thr.ip)
| `Ibow: std.put("\t{}.{}:\tBow\n", thr.tid, thr.ip)
| `Ieow: std.put("\t{}.{}:\tEow\n", thr.tid, thr.ip)
/* control flow */
| `Ifork (l, r): std.put("\t{}.{}:\tFork {}, {}\n", thr.tid, thr.ip, l, r)
| `Ijmp ip: std.put("\t{}.{}:\tJmp {}\n", thr.tid, thr.ip, ip)
| `Imatch m: std.put("\t{}.{}:\tMatch {}\n", thr.tid, thr.ip, m)
;;
}
/* 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 == '_'
}