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#include <u.h>
#include <libc.h>
int multi;
vlong count;
char *status = nil;
int
line(int fd, char *file)
{
char c;
int m, n, nalloc;
char *buf;
nalloc = 0;
buf = nil;
for(m=0; ; ){
n = read(fd, &c, 1);
if(n < 0){
fprint(2, "read: error reading %s: %r\n", file);
exits("read error");
}
if(n == 0){
if(m == 0)
status = "eof";
break;
}
if(m == nalloc){
nalloc += 1024;
buf = realloc(buf, nalloc);
if(buf == nil){
fprint(2, "read: malloc error: %r\n");
exits("malloc");
}
}
buf[m++] = c;
if(c == '\n')
break;
}
if(m > 0)
write(1, buf, m);
free(buf);
return m;
}
void
lines(int fd, char *file)
{
do{
if(line(fd, file) == 0)
break;
}while(multi || --count > 0);
}
void
chars(int fd, char *file)
{
char buf[8*1024];
vlong m;
int n;
for(m = 0; m < count; m += n){
n = sizeof(buf);
if(n > (count - m))
n = count - m;
if((n = read(fd, buf, n)) < 0){
fprint(2, "read: error reading %s: %r\n", file);
exits("read error");
}
if(n == 0){
if(m == 0)
status = "eof";
break;
}
write(1, buf, n);
}
}
void
runes(int fd, char *file)
{
char buf[8*1024], *s, *e;
Rune r;
while(count > 0){
e = buf + read(fd, buf, count + UTFmax < sizeof buf ? count : sizeof buf - UTFmax);
if(e < buf){
fprint(2, "read: error reading %s: %r\n", file);
exits("read error");
}
if(e == buf)
break;
for(s = buf; s < e && fullrune(s, e - s); s += chartorune(&r, s))
count--;
if(s < e){
while(!fullrune(s, e - s))
switch(read(fd, e, 1)){
case -1:
fprint(2, "read: error reading %s: %r\n", file);
exits("read error");
case 0:
fprint(2, "warning: partial rune at end of %s: %r\n", file);
write(1, buf, e - buf);
return;
case 1:
e++;
break;
}
count--;
}
write(1, buf, e - buf);
}
}
void
usage(void)
{
fprint(2, "usage: read [ -m | -n nlines | -c nbytes | -r nrunes ] [ file ... ]\n");
exits("usage");
}
void
main(int argc, char *argv[])
{
void (*proc)(int, char*);
int i, fd;
proc = lines;
ARGBEGIN{
case 'c':
count = atoll(EARGF(usage()));
proc = chars;
break;
case 'r':
count = atoll(EARGF(usage()));
proc = runes;
break;
case 'n':
count = atoi(EARGF(usage()));
break;
case 'm':
multi = 1;
break;
default:
usage();
}ARGEND
if(argc == 0)
(*proc)(0, "<stdin>");
else
for(i=0; i<argc; i++){
fd = open(argv[i], OREAD);
if(fd < 0){
fprint(2, "read: can't open %s: %r\n", argv[i]);
exits("open");
}
(*proc)(fd, argv[i]);
close(fd);
}
exits(status);
}
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