path: root/src/printf.c

/* printf - format and print data
   Copyright (C) 90, 91, 92, 93, 94, 1995 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., 675 Mass Ave, Cambridge, MA 02139, 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
   \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> */

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

#include "system.h"
#include "version.h"
#include "long-options.h"
#include "error.h"

#ifndef STDC_HEADERS
double strtod ();
long strtol ();
unsigned long strtoul ();
#endif

#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')

char *xmalloc ();

static double xstrtod __P ((char *s));
static int print_esc __P ((char *escstart));
static int print_formatted __P ((char *format, int argc, char **argv));
static long xstrtol __P ((char *s));
static unsigned long xstrtoul __P ((char *s));
static void print_direc __P ((char *start, size_t length, int field_width, int precision, char *argument));
static void print_esc_char __P ((int c));
static void print_esc_string __P ((char *str));
static void verify __P ((char *s, char *end));

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

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

static 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);
      printf (_("\
Print ARGUMENT(s) according to FORMAT.\n\
\n\
  --help      display this help and exit\n\
  --version   output version information and exit\n\
\n\
FORMAT controls the output as in C printf.  Interpreted sequences are:\n\
\n\
  \\\"      double quote\n\
  \\0NNN   character with octal value NNN (0 to 3 digits)\n\
  \\\\      backslash\n\
  \\a      alert (BEL)\n\
  \\b      backspace\n\
  \\c      produce no further output\n\
  \\f      form feed\n\
  \\n      new line\n\
  \\r      carriage return\n\
  \\t      horizontal tab\n\
  \\v      vertical tab\n\
  \\xNNN   character with hexadecimal value NNN (1 to 3 digits)\n\
\n\
  %%%%      a single %%\n\
  %%b      ARGUMENT as a string with `\\' escapes interpreted\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\
"));
    }
  exit (status);
}

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

  program_name = argv[0];
  exit_status = 0;

  parse_long_options (argc, argv, "printf", version_string, usage);

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

  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);

  exit (exit_status);
}

/* 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 (char *format, int argc, char **argv)
{
  int save_argc = argc;		/* Preserve original value.  */
  char *f;			/* Pointer into `format'.  */
  char *direc_start;		/* Start of % directive.  */
  size_t direc_length;		/* Length of % directive.  */
  int field_width;		/* Arg to first '*', or -1 if none.  */
  int precision;		/* Arg to second '*', or -1 if none.  */

  for (f = format; *f; ++f)
    {
      switch (*f)
	{
	case '%':
	  direc_start = f++;
	  direc_length = 1;
	  field_width = precision = -1;
	  if (*f == '%')
	    {
	      putchar ('%');
	      break;
	    }
	  if (*f == 'b')
	    {
	      if (argc > 0)
		{
		  print_esc_string (*argv);
		  ++argv;
		  --argc;
		}
	      break;
	    }
	  if (strchr ("-+ #", *f))
	    {
	      ++f;
	      ++direc_length;
	    }
	  if (*f == '*')
	    {
	      ++f;
	      ++direc_length;
	      if (argc > 0)
		{
		  field_width = xstrtoul (*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);
		      ++argv;
		      --argc;
		    }
		  else
		    precision = 0;
		}
	      else
		while (ISDIGIT (*f))
		  {
		    ++f;
		    ++direc_length;
		  }
	    }
	  if (*f == 'l' || *f == 'L' || *f == 'h')
	    {
	      ++f;
	      ++direc_length;
	    }
	  if (!strchr ("diouxXfeEgGcs", *f))
	    error (1, 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);
	  break;

	default:
	  putchar (*f);
	}
    }

  return save_argc - argc;
}

/* Print a \ escape sequence starting at ESCSTART.
   Return the number of characters in the escape sequence
   besides the backslash. */

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

  /* \0ooo and \xhhh escapes have maximum length of 3 chars. */
  if (*p == 'x')
    {
      for (esc_length = 0, ++p;
	   esc_length < 3 && ISXDIGIT (*p);
	   ++esc_length, ++p)
	esc_value = esc_value * 16 + hextobin (*p);
      if (esc_length == 0)
	error (1, 0, _("missing hexadecimal number in escape"));
      putchar (esc_value);
    }
  else if (*p == '0')
    {
      for (esc_length = 0, ++p;
	   esc_length < 3 && isodigit (*p);
	   ++esc_length, ++p)
	esc_value = esc_value * 8 + octtobin (*p);
      putchar (esc_value);
    }
  else if (strchr ("\"\\abcfnrtv", *p))
    print_esc_char (*p++);
  else
    error (1, 0, _("\\%c: invalid escape"), *p);
  return p - escstart - 1;
}

/* 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 (0);
      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 string STR, evaluating \ escapes. */

static void
print_esc_string (char *str)
{
  for (; *str; str++)
    if (*str == '\\')
      str += print_esc (str);
    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 non-negative, they are args for
   '*' values in those fields. */

static void
print_direc (char *start, size_t length, int field_width, int precision, 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 < 0)
	{
	  if (precision < 0)
	    printf (p, xstrtol (argument));
	  else
	    printf (p, precision, xstrtol (argument));
	}
      else
	{
	  if (precision < 0)
	    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 < 0)
	{
	  if (precision < 0)
	    printf (p, xstrtoul (argument));
	  else
	    printf (p, precision, xstrtoul (argument));
	}
      else
	{
	  if (precision < 0)
	    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 < 0)
	{
	  if (precision < 0)
	    printf (p, xstrtod (argument));
	  else
	    printf (p, precision, xstrtod (argument));
	}
      else
	{
	  if (precision < 0)
	    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 < 0)
	{
	  if (precision < 0)
	    printf (p, argument);
	  else
	    printf (p, precision, argument);
	}
      else
	{
	  if (precision < 0)
	    printf (p, field_width, argument);
	  else
	    printf (p, field_width, precision, argument);
	}
      break;
    }

  free (p);
}

static unsigned long
xstrtoul (char *s)
{
  char *end;
  unsigned long val;

  errno = 0;
  val = strtoul (s, &end, 0);
  verify (s, end);
  return val;
}

static long
xstrtol (char *s)
{
  char *end;
  long val;

  errno = 0;
  val = strtol (s, &end, 0);
  verify (s, end);
  return val;
}

static double
xstrtod (char *s)
{
  char *end;
  double val;

  errno = 0;
  val = strtod (s, &end);
  verify (s, end);
  return val;
}

static void
verify (char *s, 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;
    }
}