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/* printf.c - Format and Print the data.
*
* Copyright 2014 Sandeep Sharma <sandeep.jack2756@gmail.com>
* Copyright 2014 Kyungwan Han <asura321@gmail.com>
*
* See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/printf.html
*
* todo: *m$ ala printf("%1$d:%2$.*3$d:%4$.*3$d\n", hour, min, precision, sec);
USE_PRINTF(NEWTOY(printf, "<1", TOYFLAG_USR|TOYFLAG_BIN))
config PRINTF
bool "printf"
default n
help
usage: printf FORMAT [ARGUMENT...]
Format and print ARGUMENT(s) according to FORMAT, using C printf syntax
(% escapes for cdeEfgGiosuxX, \ escapes for abefnrtv0 or \OCTAL or \xHEX).
*/
#define FOR_printf
#include "toys.h"
// Detect matching character (return true/valse) and advance pointer if match.
static int eat(char **s, char c)
{
int x = (**s == c);
if (x) ++*s;
return x;
}
// Parse escape sequences.
static int handle_slash(char **esc_val)
{
char *ptr = *esc_val;
int len, base = 0;
unsigned result = 0, num;
if (*ptr == 'c') xexit();
// 0x12 hex escapes have 1-2 digits, \123 octal escapes have 1-3 digits.
if (eat(&ptr, 'x')) base = 16;
else if (*ptr >= '0' && *ptr <= '8') base = 8;
len = (char []){0,3,2}[base/8];
// Not a hex or octal escape? (This catches trailing \)
if (!len) {
if (!(result = unescape(*ptr))) result = '\\';
else ++*esc_val;
return result;
}
while (len) {
num = tolower(*ptr) - '0';
if (num >= 'a'-'0') num += '0'-'a'+10;
if (num >= base) {
// Don't parse invalid hex value ala "\xvd", print it verbatim
if (base == 16 && len == 2) {
ptr--;
result = '\\';
}
break;
}
result = (result*base)+num;
ptr++;
len--;
}
*esc_val = ptr;
return result;
}
void printf_main(void)
{
char **arg = toys.optargs+1;
// Repeat format until arguments consumed
for (;;) {
int seen = 0;
char *f = *toys.optargs;
// Loop through characters in format
while (*f) {
if (eat(&f, '\\')) putchar(handle_slash(&f));
else if (!eat(&f, '%') || *f == '%') putchar(*f++);
// Handle %escape
else {
char c, *end = 0, *aa, *to = toybuf;
int wp[] = {0,-1}, i;
// Parse width.precision between % and type indicator.
*to++ = '%';
while (strchr("-+# '0", *f) && (to-toybuf)<10) *to++ = *f++;
for (i=0; i<2; i++) {
if (eat(&f, '*')) {
if (*arg) wp[i] = atolx(*arg++);
} else while (*f >= '0' && *f <= '9') {
if (wp[i]<0) wp[i] = 0;
wp[i] = (wp[i]*10)+(*f++)-'0';
}
if (!eat(&f, '.')) break;
}
c = *f++;
seen = sprintf(to, "*.*%c", c);;
errno = 0;
aa = *arg ? *arg++ : "";
// Output %esc using parsed format string
if (c == 'b') {
while (*aa) putchar(eat(&aa, '\\') ? handle_slash(&aa) : *aa++);
continue;
} else if (c == 'c') printf(toybuf, wp[0], wp[1], *aa);
else if (c == 's') printf(toybuf, wp[0], wp[1], aa);
else if (strchr("diouxX", c)) {
long ll;
if (*aa == '\'' || *aa == '"') ll = aa[1];
else ll = strtoll(aa, &end, 0);
sprintf(to, "*.*ll%c", c);
printf(toybuf, wp[0], wp[1], ll);
} else if (strchr("feEgG", c)) {
long double ld = strtold(aa, &end);
sprintf(to, "*.*L%c", c);
printf(toybuf, wp[0], wp[1], ld);
} else error_exit("bad %%%c@%ld", c, f-*toys.optargs);
if (end && (errno || *end)) perror_msg("bad %%%c %s", c, aa);
}
}
// Posix says to keep looping through format until we consume all args.
// This only works if the format actually consumed at least one arg.
if (!seen || !*arg) break;
}
}
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