libiberty/concat.c

/* Concatenate variable number of strings.
   Copyright (C) 1991-2025 Free Software Foundation, Inc.
   Written by Fred Fish @ Cygnus Support

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

Libiberty 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with libiberty; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
Boston, MA 02110-1301, USA.  */


/*

@deftypefn Extension char* concat (const char *@var{s1}, const char *@var{s2}, @
  @dots{}, @code{NULL})

Concatenate zero or more of strings and return the result in freshly
@code{xmalloc}ed memory.  The argument list is terminated by the first
@code{NULL} pointer encountered.  Pointers to empty strings are ignored.

@end deftypefn

*/


#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "ansidecl.h"
#include "libiberty.h"
#include <sys/types.h>		/* size_t */

#include <stdarg.h>

# if HAVE_STRING_H
#  include <string.h>
# else
#  if HAVE_STRINGS_H
#   include <strings.h>
#  endif
# endif

#if HAVE_STDLIB_H
#include <stdlib.h>
#endif

static inline unsigned long vconcat_length (const char *, va_list);
static inline unsigned long
vconcat_length (const char *first, va_list args)
{
  unsigned long length = 0;
  const char *arg;

  for (arg = first; arg ; arg = va_arg (args, const char *))
    length += strlen (arg);

  return length;
}

static inline char *
vconcat_copy (char *dst, const char *first, va_list args)
{
  char *end = dst;
  const char *arg;

  for (arg = first; arg ; arg = va_arg (args, const char *))
    {
      unsigned long length = strlen (arg);
      memcpy (end, arg, length);
      end += length;
    }
  *end = '\000';

  return dst;
}

/* @undocumented concat_length */

unsigned long
concat_length (const char *first, ...)
{
  unsigned long length;
  va_list args;

  va_start (args, first);
  length = vconcat_length (first, args);
  va_end (args);

  return length;
}

/* @undocumented concat_copy */

char *
concat_copy (char *dst, const char *first, ...)
{
  char *save_dst;
  va_list args;

  va_start (args, first);
  vconcat_copy (dst, first, args);
  save_dst = dst; /* With K&R C, dst goes out of scope here.  */
  va_end (args);

  return save_dst;
}

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
char *libiberty_concat_ptr;
#ifdef __cplusplus
}
#endif /* __cplusplus */

/* @undocumented concat_copy2 */

char *
concat_copy2 (const char *first, ...)
{
  va_list args;
  va_start (args, first);
  vconcat_copy (libiberty_concat_ptr, first, args);
  va_end (args);

  return libiberty_concat_ptr;
}

char *
concat (const char *first, ...)
{
  char *newstr;
  va_list args;

  /* First compute the size of the result and get sufficient memory.  */
  va_start (args, first);
  newstr = XNEWVEC (char, vconcat_length (first, args) + 1);
  va_end (args);

  /* Now copy the individual pieces to the result string. */
  va_start (args, first);
  vconcat_copy (newstr, first, args);
  va_end (args);

  return newstr;
}

/*

@deftypefn Extension char* reconcat (char *@var{optr}, const char *@var{s1}, @
  @dots{}, @code{NULL})

Same as @code{concat}, except that if @var{optr} is not @code{NULL} it
is freed after the string is created.  This is intended to be useful
when you're extending an existing string or building up a string in a
loop:

@example
  str = reconcat (str, "pre-", str, NULL);
@end example

@end deftypefn

*/

char *
reconcat (char *optr, const char *first, ...)
{
  char *newstr;
  va_list args;

  /* First compute the size of the result and get sufficient memory.  */
  va_start (args, first);
  newstr = XNEWVEC (char, vconcat_length (first, args) + 1);
  va_end (args);

  /* Now copy the individual pieces to the result string. */
  va_start (args, first);
  vconcat_copy (newstr, first, args);
  if (optr) /* Done before VA_CLOSE so optr stays in scope for K&R C.  */
    free (optr);
  va_end (args);

  return newstr;
}

#ifdef MAIN
#define NULLP (char *)0

/* Simple little test driver. */

#include <stdio.h>

int
main (void)
{
  printf ("\"\" = \"%s\"\n", concat (NULLP));
  printf ("\"a\" = \"%s\"\n", concat ("a", NULLP));
  printf ("\"ab\" = \"%s\"\n", concat ("a", "b", NULLP));
  printf ("\"abc\" = \"%s\"\n", concat ("a", "b", "c", NULLP));
  printf ("\"abcd\" = \"%s\"\n", concat ("ab", "cd", NULLP));
  printf ("\"abcde\" = \"%s\"\n", concat ("ab", "c", "de", NULLP));
  printf ("\"abcdef\" = \"%s\"\n", concat ("", "a", "", "bcd", "ef", NULLP));
  return 0;
}

#endif