libiberty/concat.c

   1 /* Concatenate variable number of strings.
   2    Copyright (C) 1991, 1994 Free Software Foundation, Inc.
   3    Written by Fred Fish @ Cygnus Support
   4
   5 This file is part of the libiberty library.
   6 Libiberty is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU Library General Public
   8 License as published by the Free Software Foundation; either
   9 version 2 of the License, or (at your option) any later version.
  10
  11 Libiberty is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 Library General Public License for more details.
  15
  16 You should have received a copy of the GNU Library General Public
  17 License along with libiberty; see the file COPYING.LIB.  If
  18 not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21
  22 /*
  23
  24 NAME
  25
  26         concat -- concatenate a variable number of strings
  27
  28 SYNOPSIS
  29
  30         #include <varargs.h>
  31
  32         char *concat (s1, s2, s3, ..., NULL)
  33
  34 DESCRIPTION
  35
  36         Concatenate a variable number of strings and return the result
  37         in freshly malloc'd memory.
  38
  39         Returns NULL if insufficient memory is available.  The argument
  40         list is terminated by the first NULL pointer encountered.  Pointers
  41         to empty strings are ignored.
  42
  43 NOTES
  44
  45         This function uses xmalloc() which is expected to be a front end
  46         function to malloc() that deals with low memory situations.  In
  47         typical use, if malloc() returns NULL then xmalloc() diverts to an
  48         error handler routine which never returns, and thus xmalloc will
  49         never return a NULL pointer.  If the client application wishes to
  50         deal with low memory situations itself, it should supply an xmalloc
  51         that just directly invokes malloc and blindly returns whatever
  52         malloc returns.
  53 */
  54
  55
  56 #include "ansidecl.h"
  57 #include "libiberty.h"
  58
  59 #ifdef ANSI_PROTOTYPES
  60 #include <stdarg.h>
  61 #else
  62 #include <varargs.h>
  63 #endif
  64
  65 #ifdef __STDC__
  66 #include <stddef.h>
  67 extern size_t strlen (const char *s);
  68 #else
  69 extern int strlen ();
  70 #endif
  71
  72 #define NULLP (char *)0
  73
  74 /* VARARGS */
  75 #ifdef ANSI_PROTOTYPES
  76 char *
  77 concat (const char *first, ...)
  78 #else
  79 char *
  80 concat (va_alist)
  81      va_dcl
  82 #endif
  83 {
  84   register int length;
  85   register char *newstr;
  86   register char *end;
  87   register const char *arg;
  88   va_list args;
  89 #ifndef ANSI_PROTOTYPES
  90   const char *first;
  91 #endif
  92
  93   /* First compute the size of the result and get sufficient memory. */
  94
  95 #ifdef ANSI_PROTOTYPES
  96   va_start (args, first);
  97 #else
  98   va_start (args);
  99   first = va_arg (args, const char *);
 100 #endif
 101
 102   if (first == NULLP)
 103     length = 0;
 104   else
 105     {
 106       length = strlen (first);
 107       while ((arg = va_arg (args, const char *)) != NULLP)
 108         {
 109           length += strlen (arg);
 110         }
 111     }
 112   newstr = (char *) xmalloc (length + 1);
 113   va_end (args);
 114
 115   /* Now copy the individual pieces to the result string. */
 116
 117   if (newstr != NULLP)
 118     {
 119 #ifdef ANSI_PROTOTYPES
 120       va_start (args, first);
 121 #else
 122       va_start (args);
 123       first = va_arg (args, const char *);
 124 #endif
 125       end = newstr;
 126       if (first != NULLP)
 127         {
 128           arg = first;
 129           while (*arg)
 130             {
 131               *end++ = *arg++;
 132             }
 133           while ((arg = va_arg (args, const char *)) != NULLP)
 134             {
 135               while (*arg)
 136                 {
 137                   *end++ = *arg++;
 138                 }
 139             }
 140         }
 141       *end = '\000';
 142       va_end (args);
 143     }
 144
 145   return (newstr);
 146 }
 147
 148 #ifdef MAIN
 149
 150 /* Simple little test driver. */
 151
 152 #include <stdio.h>
 153
 154 int
 155 main ()
 156 {
 157   printf ("\"\" = \"%s\"\n", concat (NULLP));
 158   printf ("\"a\" = \"%s\"\n", concat ("a", NULLP));
 159   printf ("\"ab\" = \"%s\"\n", concat ("a", "b", NULLP));
 160   printf ("\"abc\" = \"%s\"\n", concat ("a", "b", "c", NULLP));
 161   printf ("\"abcd\" = \"%s\"\n", concat ("ab", "cd", NULLP));
 162   printf ("\"abcde\" = \"%s\"\n", concat ("ab", "c", "de", NULLP));
 163   printf ("\"abcdef\" = \"%s\"\n", concat ("", "a", "", "bcd", "ef", NULLP));
 164   return 0;
 165 }
 166
 167 #endif