coreutils/printf.c

/* vi: set sw=4 ts=4: */
/* printf - format and print data

   Copyright 1999 Dave Cinege
   Portions copyright (C) 1990-1996 Free Software Foundation, Inc.

   Licensed under GPL v2 or later, see file LICENSE in this tarball for details.
*/

/* 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

   The 'format' argument is re-used as many times as necessary
   to convert all of the given arguments.

   David MacKenzie <djm@gnu.ai.mit.edu> */


//   19990508 Busy Boxed! Dave Cinege

#include "libbb.h"

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);
}

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)
{
	char saved;

	saved = format[fmt_length];
	format[fmt_length] = '\0';

	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;
	}

	format[fmt_length] = saved;
}

/* Print the text in FORMAT, using ARGV for arguments to any '%' directives.
   Return advanced ARGV.  */
static char **print_formatted(char *f, char **argv)
{
	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) {
					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) {
						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;
			}
			/*
			if (!strchr ("diouxXfeEgGcs", *f))
			fprintf(stderr, "%%%c: invalid directive", *f);
			*/
			++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);
		}
	}

	return argv;
}

int printf_main(int argc ATTRIBUTE_UNUSED, char **argv)
{
	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] == '\0')
		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");
	*/

	return EXIT_SUCCESS;
}