path: root/src/printf.c

/* printf - format and print data
   Copyright (C) 1990-2003, Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* 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
   \ooo = octal number (ooo is 1 to 3 digits)
   \xhh = hexadecimal number (hhh is 1 to 2 digits)
   \uhhhh = 16-bit Unicode character (hhhh is 4 digits)
   \Uhhhhhhhh = 32-bit Unicode character (hhhhhhhh is 8 digits)

   Additional directive:

   %b = print an argument string, interpreting backslash escapes,
     except that octal escapes are of the form \0 or \0ooo.

   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> */

#include <config.h>
#include <stdio.h>
#include <sys/types.h>
#include <getopt.h>

#include "system.h"
#include "c-strtod.h"
#include "long-options.h"
#include "error.h"
#include "unicodeio.h"

/* The official name of this program (e.g., no `g' prefix).  */
#define PROGRAM_NAME "printf"

#define AUTHORS "David MacKenzie"

#define isodigit(c) ((c) >= '0' && (c) <= '7')
#define hextobin(c) ((c) >= 'a' && (c) <= 'f' ? (c) - 'a' + 10 : \
		     (c) >= 'A' && (c) <= 'F' ? (c) - 'A' + 10 : (c) - '0')
#define octtobin(c) ((c) - '0')

/* A value for field_width or precision that indicates it was not specified.  */
#define UNSPECIFIED INT_MIN

/* The value to return to the calling program.  */
static int exit_status;

/* Non-zero if the POSIXLY_CORRECT environment variable is set.  */
static int posixly_correct;

/* This message appears in N_() here rather than just in _() below because
   the sole use would have been in a #define.  */
static char *const cfcc_msg =
 N_("warning: %s: character(s) following character constant have been ignored");

/* The name this program was run with. */
char *program_name;

void
usage (int status)
{
  if (status != 0)
    fprintf (stderr, _("Try `%s --help' for more information.\n"),
	     program_name);
  else
    {
      printf (_("\
Usage: %s FORMAT [ARGUMENT]...\n\
  or:  %s OPTION\n\
"),
	      program_name, program_name);
      fputs (_("\
Print ARGUMENT(s) according to FORMAT.\n\
\n\
"), stdout);
      fputs (HELP_OPTION_DESCRIPTION, stdout);
      fputs (VERSION_OPTION_DESCRIPTION, stdout);
      fputs (_("\
\n\
FORMAT controls the output as in C printf.  Interpreted sequences are:\n\
\n\
  \\\"      double quote\n\
  \\NNN    character with octal value NNN (1 to 3 digits)\n\
  \\\\      backslash\n\
"), stdout);
      fputs (_("\
  \\a      alert (BEL)\n\
  \\b      backspace\n\
  \\c      produce no further output\n\
  \\f      form feed\n\
"), stdout);
      fputs (_("\
  \\n      new line\n\
  \\r      carriage return\n\
  \\t      horizontal tab\n\
  \\v      vertical tab\n\
"), stdout);
      fputs (_("\
  \\xNN    byte with hexadecimal value NN (1 to 2 digits)\n\
\n\
  \\uNNNN  character with hexadecimal value NNNN (4 digits)\n\
  \\UNNNNNNNN  character with hexadecimal value NNNNNNNN (8 digits)\n\
"), stdout);
      fputs (_("\
  %%      a single %\n\
  %b      ARGUMENT as a string with `\\' escapes interpreted,\n\
            except that octal escapes are of the form \\0 or \\0NNN\n\
\n\
and all C format specifications ending with one of diouxXfeEgGcs, with\n\
ARGUMENTs converted to proper type first.  Variable widths are handled.\n\
"), stdout);
      printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
    }
  exit (status);
}

static void
verify (const char *s, const char *end)
{
  if (errno)
    {
      error (0, errno, "%s", s);
      exit_status = 1;
    }
  else if (*end)
    {
      if (s == end)
	error (0, 0, _("%s: expected a numeric value"), s);
      else
	error (0, 0, _("%s: value not completely converted"), s);
      exit_status = 1;
    }
}

#define STRTOX(TYPE, FUNC_NAME, LIB_FUNC_EXPR)				 \
static TYPE								 \
FUNC_NAME (s)								 \
     const char *s;							 \
{									 \
  char *end;								 \
  TYPE val;								 \
									 \
  if (*s == '\"' || *s == '\'')						 \
    {									 \
      val = *(unsigned char *) ++s;					 \
      /* If POSIXLY_CORRECT is not set, then give a warning that there	 \
	 are characters following the character constant and that GNU	 \
	 printf is ignoring those characters.  If POSIXLY_CORRECT *is*	 \
	 set, then don't give the warning.  */				 \
      if (*++s != 0 && !posixly_correct)				 \
	error (0, 0, _(cfcc_msg), s);					 \
    }									 \
  else									 \
    {									 \
      errno = 0;							 \
      val = LIB_FUNC_EXPR;						 \
      verify (s, end);							 \
    }									 \
  return val;								 \
}									 \

STRTOX (unsigned long int, xstrtoul, (strtoul (s, &end, 0)))
STRTOX (long int,          xstrtol,  (strtol  (s, &end, 0)))
STRTOX (double,            xstrtod,  (c_strtod (s, &end)))

/* Output a single-character \ escape.  */

static void
print_esc_char (int c)
{
  switch (c)
    {
    case 'a':			/* Alert. */
      putchar (7);
      break;
    case 'b':			/* Backspace. */
      putchar (8);
      break;
    case 'c':			/* Cancel the rest of the output. */
      exit (EXIT_SUCCESS);
      break;
    case 'f':			/* Form feed. */
      putchar (12);
      break;
    case 'n':			/* New line. */
      putchar (10);
      break;
    case 'r':			/* Carriage return. */
      putchar (13);
      break;
    case 't':			/* Horizontal tab. */
      putchar (9);
      break;
    case 'v':			/* Vertical tab. */
      putchar (11);
      break;
    default:
      putchar (c);
      break;
    }
}

/* Print a \ escape sequence starting at ESCSTART.
   Return the number of characters in the escape sequence
   besides the backslash.
   If OCTAL_0 is nonzero, octal escapes are of the form \0ooo, where o
   is an octal digit; otherwise they are of the form \ooo.  */

static int
print_esc (const char *escstart, bool octal_0)
{
  register const char *p = escstart + 1;
  int esc_value = 0;		/* Value of \nnn escape. */
  int esc_length;		/* Length of \nnn escape. */

  if (!posixly_correct && *p == 'x')
    {
      /* A hexadecimal \xhh escape sequence must have 1 or 2 hex. digits.  */
      for (esc_length = 0, ++p;
	   esc_length < 2 && ISXDIGIT (*p);
	   ++esc_length, ++p)
	esc_value = esc_value * 16 + hextobin (*p);
      if (esc_length == 0)
	error (EXIT_FAILURE, 0, _("missing hexadecimal number in escape"));
      putchar (esc_value);
    }
  else if (isodigit (*p))
    {
      /* Parse \0ooo (if octal_0 && *p == '0') or \ooo (otherwise).
         Allow \ooo if octal_0 && *p != '0'; this is an undocumented
         extension to POSIX that is compatible with Bash 2.05b.  */
      for (esc_length = 0, p += octal_0 && *p == '0';
	   esc_length < 3 && isodigit (*p);
	   ++esc_length, ++p)
	esc_value = esc_value * 8 + octtobin (*p);
      putchar (esc_value);
    }
  else if (*p && strchr ("\"\\abcfnrtv", *p))
    print_esc_char (*p++);
  else if (!posixly_correct && (*p == 'u' || *p == 'U'))
    {
      char esc_char = *p;
      unsigned int uni_value;

      uni_value = 0;
      for (esc_length = (esc_char == 'u' ? 4 : 8), ++p;
	   esc_length > 0;
	   --esc_length, ++p)
	{
	  if (!ISXDIGIT (*p))
	    error (EXIT_FAILURE, 0, _("missing hexadecimal number in escape"));
	  uni_value = uni_value * 16 + hextobin (*p);
	}

      /* A universal character name shall not specify a character short
	 identifier in the range 00000000 through 00000020, 0000007F through
	 0000009F, or 0000D800 through 0000DFFF inclusive. A universal
	 character name shall not designate a character in the required
	 character set.  */
      if ((uni_value <= 0x9f
	   && uni_value != 0x24 && uni_value != 0x40 && uni_value != 0x60)
	  || (uni_value >= 0xd800 && uni_value <= 0xdfff))
	error (EXIT_FAILURE, 0, _("invalid universal character name \\%c%0*x"),
	       esc_char, (esc_char == 'u' ? 4 : 8), uni_value);

      print_unicode_char (stdout, uni_value, 0);
    }
  else
    {
      putchar ('\\');
      if (*p)
	{
	  putchar (*p);
	  p++;
	}
    }
  return p - escstart - 1;
}

/* Print string STR, evaluating \ escapes. */

static void
print_esc_string (const char *str)
{
  for (; *str; str++)
    if (*str == '\\')
      str += print_esc (str, true);
    else
      putchar (*str);
}

/* Output a % directive.  START is the start of the directive,
   LENGTH is its length, and ARGUMENT is its argument.
   If FIELD_WIDTH or PRECISION is UNSPECIFIED, they are args for
   '*' values in those fields. */

static void
print_direc (const char *start, size_t length, int field_width,
	     int precision, const char *argument)
{
  char *p;		/* Null-terminated copy of % directive. */

  p = xmalloc ((unsigned) (length + 1));
  strncpy (p, start, length);
  p[length] = 0;

  switch (p[length - 1])
    {
    case 'd':
    case 'i':
      if (field_width == UNSPECIFIED)
	{
	  if (precision == UNSPECIFIED)
	    printf (p, xstrtol (argument));
	  else
	    printf (p, precision, xstrtol (argument));
	}
      else
	{
	  if (precision == UNSPECIFIED)
	    printf (p, field_width, xstrtol (argument));
	  else
	    printf (p, field_width, precision, xstrtol (argument));
	}
      break;

    case 'o':
    case 'u':
    case 'x':
    case 'X':
      if (field_width == UNSPECIFIED)
	{
	  if (precision == UNSPECIFIED)
	    printf (p, xstrtoul (argument));
	  else
	    printf (p, precision, xstrtoul (argument));
	}
      else
	{
	  if (precision == UNSPECIFIED)
	    printf (p, field_width, xstrtoul (argument));
	  else
	    printf (p, field_width, precision, xstrtoul (argument));
	}
      break;

    case 'f':
    case 'e':
    case 'E':
    case 'g':
    case 'G':
      if (field_width == UNSPECIFIED)
	{
	  if (precision == UNSPECIFIED)
	    printf (p, xstrtod (argument));
	  else
	    printf (p, precision, xstrtod (argument));
	}
      else
	{
	  if (precision == UNSPECIFIED)
	    printf (p, field_width, xstrtod (argument));
	  else
	    printf (p, field_width, precision, xstrtod (argument));
	}
      break;

    case 'c':
      printf (p, *argument);
      break;

    case 's':
      if (field_width == UNSPECIFIED)
	{
	  if (precision == UNSPECIFIED)
	    printf (p, argument);
	  else
	    printf (p, precision, argument);
	}
      else
	{
	  if (precision == UNSPECIFIED)
	    printf (p, field_width, argument);
	  else
	    printf (p, field_width, precision, argument);
	}
      break;
    }

  free (p);
}

/* Print the text in FORMAT, using ARGV (with ARGC elements) for
   arguments to any `%' directives.
   Return the number of elements of ARGV used.  */

static int
print_formatted (const char *format, int argc, char **argv)
{
  int save_argc = argc;		/* Preserve original value.  */
  const char *f;		/* Pointer into `format'.  */
  const char *direc_start;	/* Start of % directive.  */
  size_t direc_length;		/* Length of % directive.  */
  int field_width;		/* Arg to first '*', or UNSPECIFIED if none. */
  int precision;		/* Arg to second '*', or UNSPECIFIED if none. */

  for (f = format; *f; ++f)
    {
      switch (*f)
	{
	case '%':
	  direc_start = f++;
	  direc_length = 1;
	  field_width = precision = UNSPECIFIED;
	  if (*f == '%')
	    {
	      putchar ('%');
	      break;
	    }
	  if (*f == 'b')
	    {
	      if (argc > 0)
		{
		  print_esc_string (*argv);
		  ++argv;
		  --argc;
		}
	      break;
	    }
	  while (*f == ' ' || *f == '#' || *f == '+' || *f == '-')
	    {
	      ++f;
	      ++direc_length;
	    }
	  if (*f == '*')
	    {
	      ++f;
	      ++direc_length;
	      if (argc > 0)
		{
		  field_width = xstrtoul (*argv);
		  if (field_width == UNSPECIFIED)
		    error (EXIT_FAILURE, 0, _("invalid field width: %s"),
			   *argv);
		  ++argv;
		  --argc;
		}
	      else
		field_width = 0;
	    }
	  else
	    while (ISDIGIT (*f))
	      {
		++f;
		++direc_length;
	      }
	  if (*f == '.')
	    {
	      ++f;
	      ++direc_length;
	      if (*f == '*')
		{
		  ++f;
		  ++direc_length;
		  if (argc > 0)
		    {
		      precision = xstrtoul (*argv);
		      if (precision == UNSPECIFIED)
			error (EXIT_FAILURE, 0, _("invalid precision: %s"),
			       *argv);
		      ++argv;
		      --argc;
		    }
		  else
		    precision = 0;
		}
	      else
		while (ISDIGIT (*f))
		  {
		    ++f;
		    ++direc_length;
		  }
	    }
	  if (*f == 'l' || *f == 'L' || *f == 'h')
	    {
	      ++f;
	      ++direc_length;
	    }
	  if (! (*f && strchr ("diouxXfeEgGcs", *f)))
	    error (EXIT_FAILURE, 0, _("%%%c: invalid directive"), *f);
	  ++direc_length;
	  if (argc > 0)
	    {
	      print_direc (direc_start, direc_length, field_width,
			   precision, *argv);
	      ++argv;
	      --argc;
	    }
	  else
	    print_direc (direc_start, direc_length, field_width,
			 precision, "");
	  break;

	case '\\':
	  f += print_esc (f, false);
	  break;

	default:
	  putchar (*f);
	}
    }

  return save_argc - argc;
}

int
main (int argc, char **argv)
{
  char *format;
  int args_used;

  initialize_main (&argc, &argv);
  program_name = argv[0];
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);

  atexit (close_stdout);

  exit_status = 0;

  /* Don't recognize --help or --version if POSIXLY_CORRECT is set.  */
  posixly_correct = (getenv ("POSIXLY_CORRECT") != NULL);
  if (!posixly_correct)
    parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
			usage, AUTHORS, (char const *) NULL);

  /* The above handles --help and --version.
     Since there is no other invocation of getopt, handle `--' here.  */
  if (1 < argc && STREQ (argv[1], "--"))
    {
      --argc;
      ++argv;
    }

  if (argc <= 1)
    {
      fprintf (stderr, _("Usage: %s format [argument...]\n"), program_name);
      exit (EXIT_FAILURE);
    }

  format = argv[1];
  argc -= 2;
  argv += 2;

  do
    {
      args_used = print_formatted (format, argc, argv);
      argc -= args_used;
      argv += args_used;
    }
  while (args_used > 0 && argc > 0);

  if (argc > 0)
    error (0, 0,
	   _("warning: ignoring excess arguments, starting with `%s'"),
	   argv[0]);

  exit (exit_status);
}