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/* seq.c - Count from first to last, by increment.
*
* Copyright 2006 Rob Landley <rob@landley.net>
*
* http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/seq.html
USE_SEQ(NEWTOY(seq, "<1>3?f:s:w[!fw]", TOYFLAG_USR|TOYFLAG_BIN))
config SEQ
bool "seq"
depends on TOYBOX_FLOAT
default y
help
usage: seq [-w|-f fmt_str] [-s sep_str] [first] [increment] last
Count from first to last, by increment. Omitted arguments default
to 1. Two arguments are used as first and last. Arguments can be
negative or floating point.
-f Use fmt_str as a printf-style floating point format string
-s Use sep_str as separator, default is a newline character
-w Pad to equal width with leading zeroes
*/
#define FOR_seq
#include "toys.h"
GLOBALS(
char *s, *f;
int precision, buflen;
)
// Ensure there's one %f escape with correct attributes
static void insanitize(char *f)
{
char *s = next_printf(f, 0);
if (!s) error_exit("bad -f no %%f");
if (-1 == stridx("aAeEfFgG", *s) || (s = next_printf(s, 0)))
error_exit("bad -f '%s'@%d", f, (int)(s-f+1));
}
// Parse a numeric argument setting *prec to the precision of this argument.
// This reproduces the "1.234e5" precision bug from upstream.
static double parsef(char *s)
{
char *dp = strchr(s, '.');
if (dp++) TT.precision = maxof(TT.precision, strcspn(dp, "eE"));
return xstrtod(s);
}
// fast integer conversion to decimal string
// TODO move to lib?
static char *itoa(char *s, int i)
{
char buf[16], *ff = buf;
unsigned n = i;
if (i<0) {
*s++ = '-';
n = -i;
}
do *ff++ = '0'+n%10; while ((n /= 10));
do *s++ = *--ff; while (ff>buf);
*s++ = '\n';
return s;
}
static char *flush_toybuf(char *ss)
{
if (ss-toybuf<TT.buflen) return ss;
xwrite(1, toybuf, ss-toybuf);
return toybuf;
}
void seq_main(void)
{
char fbuf[32], *ss;
double first = 1, increment = 1, last, dd;
int ii, inc = 1, len, slen;
// parse arguments
if (!TT.s) TT.s = "\n";
switch (toys.optc) {
case 3: increment = parsef(toys.optargs[1]);
case 2: first = parsef(*toys.optargs);
default: last = parsef(toys.optargs[toys.optc-1]);
}
// measure arguments
if (FLAG(f)) insanitize(TT.f);
for (ii = len = 0; ii<3; ii++) {
dd = (double []){first, increment, last}[ii];
len = maxof(len, snprintf(0, 0, "%.*f", TT.precision, fabs(dd)));
if (ii == 2) dd += increment;
slen = dd;
if (dd != slen) inc = 0;
}
if (!FLAG(f)) sprintf(TT.f = fbuf, "%%0%d.%df", len, TT.precision);
TT.buflen = sizeof(toybuf) - 32 - len - TT.precision - strlen(TT.s);
if (TT.buflen<0) error_exit("bad -s");
// fast path: when everything fits in an int with no flags.
if (!toys.optflags && inc) {
ii = first;
len = last;
inc = increment;
ss = toybuf;
if (inc>0) for (; ii<=len; ii += inc)
ss = flush_toybuf(itoa(ss, ii));
else if (inc<0) for (; ii>=len; ii += inc)
ss = flush_toybuf(itoa(ss, ii));
if (ss != toybuf) xwrite(1, toybuf, ss-toybuf);
return;
}
// Other implementations output nothing if increment is 0 and first > last,
// but loop forever if first < last or even first == last. We output
// nothing for all three, if you want endless output use "yes".
if (!increment) return;
// Slow path, floating point and fancy sprintf() patterns
for (ii = 0, ss = toybuf;; ii++) {
// Multiply to avoid accumulating rounding errors from increment.
dd = first+ii*increment;
if ((increment<0 && dd<last) || (increment>0 && dd>last)) break;
if (ii) ss = flush_toybuf(stpcpy(ss, TT.s));
ss += sprintf(ss, TT.f, dd);
}
*ss++ = '\n';
xwrite(1, toybuf, ss-toybuf);
}