def peek(st, ps, es, toks):
s = ps
while s < es and strchr(WHITESPACE, st[s]):
s += 1
ps = s
return (st[s] != "\0") and (strchr(toks, st[s]) != 0), ps
def gettoken(st, ps, es):
s = ps
while s < es and strchr(WHITESPACE, st[s]):
s += 1
q = s
ret = st[s]
if st[s] == "\0": # @@@ can this happen?
pass
elif st[s] in "|();&<":
s += 1
elif st[s] == ">":
s += 1
if st[s] == ">":
ret = "+"
s += 1
else:
ret = "a"
while s < es and not strchr(WHITESPACE, st[s]) and not strchr(SYMBOLS, st[s]):
s += 1
eq = s
while s < es and strchr(WHITESPACE, st[s]):
s += 1
ps = s
return ret, ps, q, eq
def grep(pattern, fd):
m = 0
buf = " " * 1024
# while (n = read(fd, buf+m, sizeof(buf)-m)) > 0
while True:
n, s = read(fd, 1024 - m)
buf = buf[:m] + s
if n <= 0:
break
m += n
p = buf
# while (q = strchr(p, '\n')) != 0
while True:
q = strchr(p, "\n")
if q == 0:
break
q = "\0" + q[1:]
if match(pattern, p):
q = "\n" + q[1:]
write(1, p, len(p) + 1 - len(q))
p = q[1:]
if p == buf:
m = 0
if m > 0:
m -= len(p) - len(buf)
# memmove(buf, p, m)
buf = p[:m] + buf[m:]
def wc(fd, name):
l = 0
w = 0
c = 0
inword = False
# while((n = read(fd, buf, sizeof(buf))) > 0)
while True:
n, buf = read(fd, 512)
if n <= 0:
break
for i in range(n):
c += 1
if buf[i] == "\n":
l += 1
if strchr(" \r\t\n\v", buf[i]):
inword = False
elif not inword:
w += 1
inword = True
if n < 0:
printf(1, "wc: read error\n")
exit_(1)
printf(1, "%d %d %d %s\n", l, w, c, name)