busybox/coreutils/printf.c

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/* vi: set sw=4 ts=4: */
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/* printf - format and print data
Copyright 1999 Dave Cinege
Portions copyright (C) 1990-1996 Free Software Foundation, Inc.
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Licensed under GPL v2 or later, see file LICENSE in this tarball for details.
*/
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/* Usage: printf format [argument...]
A front end to the printf function that lets it be used from the shell.
Backslash escapes:
\" = double quote
\\ = backslash
\a = alert (bell)
\b = backspace
\c = produce no further output
\f = form feed
\n = new line
\r = carriage return
\t = horizontal tab
\v = vertical tab
\0ooo = octal number (ooo is 0 to 3 digits)
\xhhh = hexadecimal number (hhh is 1 to 3 digits)
Additional directive:
%b = print an argument string, interpreting backslash escapes
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The 'format' argument is re-used as many times as necessary
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to convert all of the given arguments.
David MacKenzie <djm@gnu.ai.mit.edu>
*/
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// 19990508 Busy Boxed! Dave Cinege
#include "libbb.h"
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typedef void (*converter)(const char *arg, void *result);
static void multiconvert(const char *arg, void *result, converter convert)
{
char s[sizeof(int)*3 + 2];
if (*arg == '"' || *arg == '\'') {
sprintf(s, "%d", (unsigned char)arg[1]);
arg = s;
}
convert(arg, result);
/* if there was conversion error, print unconverted string */
if (errno)
fputs(arg, stderr);
}
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static void conv_strtoul(const char *arg, void *result)
{
*(unsigned long*)result = bb_strtoul(arg, NULL, 0);
}
static void conv_strtol(const char *arg, void *result)
{
*(long*)result = bb_strtol(arg, NULL, 0);
}
static void conv_strtod(const char *arg, void *result)
{
char *end;
/* Well, this one allows leading whitespace... so what */
/* What I like much less is that "-" is accepted too! :( */
*(double*)result = strtod(arg, &end);
if (end[0]) errno = ERANGE;
}
static unsigned long my_xstrtoul(const char *arg)
{
unsigned long result;
multiconvert(arg, &result, conv_strtoul);
return result;
}
static long my_xstrtol(const char *arg)
{
long result;
multiconvert(arg, &result, conv_strtol);
return result;
}
static double my_xstrtod(const char *arg)
{
double result;
multiconvert(arg, &result, conv_strtod);
return result;
}
static void print_esc_string(char *str)
{
for (; *str; str++) {
if (*str == '\\') {
str++;
bb_putchar(bb_process_escape_sequence((const char **)&str));
} else {
bb_putchar(*str);
}
}
}
static void print_direc(char *format, unsigned fmt_length,
int field_width, int precision,
const char *argument)
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{
char saved;
saved = format[fmt_length];
format[fmt_length] = '\0';
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switch (format[fmt_length - 1]) {
case 'd':
case 'i':
if (field_width < 0) {
if (precision < 0)
printf(format, my_xstrtol(argument));
else
printf(format, precision, my_xstrtol(argument));
} else {
if (precision < 0)
printf(format, field_width, my_xstrtol(argument));
else
printf(format, field_width, precision, my_xstrtol(argument));
}
break;
case 'o':
case 'u':
case 'x':
case 'X':
if (field_width < 0) {
if (precision < 0)
printf(format, my_xstrtoul(argument));
else
printf(format, precision, my_xstrtoul(argument));
} else {
if (precision < 0)
printf(format, field_width, my_xstrtoul(argument));
else
printf(format, field_width, precision, my_xstrtoul(argument));
}
break;
case 'f':
case 'e':
case 'E':
case 'g':
case 'G':
if (field_width < 0) {
if (precision < 0)
printf(format, my_xstrtod(argument));
else
printf(format, precision, my_xstrtod(argument));
} else {
if (precision < 0)
printf(format, field_width, my_xstrtod(argument));
else
printf(format, field_width, precision, my_xstrtod(argument));
}
break;
case 'c':
printf(format, *argument);
break;
case 's':
if (field_width < 0) {
if (precision < 0)
printf(format, argument);
else
printf(format, precision, argument);
} else {
if (precision < 0)
printf(format, field_width, argument);
else
printf(format, field_width, precision, argument);
}
break;
}
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format[fmt_length] = saved;
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}
/* Print the text in FORMAT, using ARGV for arguments to any '%' directives.
Return advanced ARGV. */
static char **print_formatted(char *f, char **argv)
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{
char *direc_start; /* Start of % directive. */
unsigned direc_length; /* Length of % directive. */
int field_width; /* Arg to first '*', or -1 if none. */
int precision; /* Arg to second '*', or -1 if none. */
char **saved_argv = argv;
for (; *f; ++f) {
switch (*f) {
case '%':
direc_start = f++;
direc_length = 1;
field_width = precision = -1;
if (*f == '%') {
bb_putchar('%');
break;
}
if (*f == 'b') {
if (*argv) {
print_esc_string(*argv);
++argv;
}
break;
}
if (strchr("-+ #", *f)) {
++f;
++direc_length;
}
if (*f == '*') {
++f;
++direc_length;
if (*argv) {
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field_width = my_xstrtoul(*argv);
++argv;
} else
field_width = 0;
} else {
while (isdigit(*f)) {
++f;
++direc_length;
}
}
if (*f == '.') {
++f;
++direc_length;
if (*f == '*') {
++f;
++direc_length;
if (*argv) {
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precision = my_xstrtoul(*argv);
++argv;
} else
precision = 0;
} else
while (isdigit(*f)) {
++f;
++direc_length;
}
}
if (*f == 'l' || *f == 'L' || *f == 'h') {
++f;
++direc_length;
}
/* needed - try "printf %" without it */
if (!strchr("diouxXfeEgGcs", *f)) {
bb_error_msg("invalid directive '%s'", direc_start);
/* causes main() to exit with error */
return saved_argv - 1;
}
++direc_length;
if (*argv) {
print_direc(direc_start, direc_length, field_width,
precision, *argv);
++argv;
} else
print_direc(direc_start, direc_length, field_width,
precision, "");
break;
case '\\':
if (*++f == 'c') {
return saved_argv; /* causes main() to exit */
}
bb_putchar(bb_process_escape_sequence((const char **)&f));
f--;
break;
default:
bb_putchar(*f);
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}
}
return argv;
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}
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int printf_main(int argc UNUSED_PARAM, char **argv)
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{
char *format;
char **argv2;
/* We must check that stdout is not closed.
* The reason for this is highly non-obvious.
* printf_main is used from shell.
* Shell must correctly handle 'printf "%s" foo'
* if stdout is closed. With stdio, output gets shoveled into
* stdout buffer, and even fflush cannot clear it out. It seems that
* even if libc receives EBADF on write attempts, it feels determined
* to output data no matter what. So it will try later,
* and possibly will clobber future output. Not good. */
if (dup2(1, 1) != 1)
return -1;
/* bash builtin errors out on "printf '-%s-\n' foo",
* coreutils-6.9 works. Both work with "printf -- '-%s-\n' foo".
* We will mimic coreutils. */
if (argv[1] && argv[1][0] == '-' && argv[1][1] == '-' && !argv[1][2])
argv++;
if (!argv[1])
bb_show_usage();
format = argv[1];
argv2 = argv + 2;
do {
argv = argv2;
argv2 = print_formatted(format, argv);
} while (argv2 > argv && *argv2);
/* coreutils compat (bash doesn't do this):
if (*argv)
fprintf(stderr, "excess args ignored");
*/
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return (argv2 < argv); /* if true, print_formatted errored out */
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}