#ifdef COMPAT_TAIL
/* This version is strictly compatible with the old version */
int tail(string fname) {
string str;
int offset = file_size(fname);
if (offset < 0)
return 0;
offset -= 54 * 20;
if (offset < 0) offset = 0;
str = read_bytes(fname, offset, 1080);
if (!str) return 0;
if (offset) str = str[strsrch(str, "\n")+1..];
write(str);
return 1;
}
#else
/* This version is slightly extended and compatible in spirit, but doesn't
* reproduce the oddities of the original tail() efun. Note that it also
* returns the string, so write(tail(fname)) is needed for strict
* compatibility.
*/
varargs string tail(string fname, int nlines) {
int chunk = nlines * 80;
int offset = file_size(fname);
int num_nl, p, skip;
string str = "";
while (offset > 0 && num_nl <= nlines) {
num_nl = 0;
offset -= chunk;
if (offset < 0) {
chunk += offset; /* negative */
offset = 0;
}
str = read_bytes(fname, offset, chunk) + str;
p = -1;
while (p < sizeof(str)-1 && p = member_array('\n', str, p+1))
num_nl++;
}
skip = num_nl - nlines;
p = -1;
while (skip--)
p = member_array('\n', str, p+1);
return str[p..];
}
#endif
