gcc/dyn-string.c

   1 /* An abstract string datatype.
   2    Copyright (C) 1998 Free Software Foundation, Inc.
   3    Contributed by Mark Mitchell (mark@markmitchell.com).
   4
   5    This file is part of GNU CC.
   6
   7    GNU CC is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2, or (at your option)
  10    any later version.
  11
  12    GNU CC is distributed in the hope that it will be useful, but
  13    WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GNU CC; see the file COPYING.  If not, write to the Free
  19    Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "gansidecl.h"
  24 #include "dyn-string.h"
  25
  26 extern char *xmalloc ();
  27 extern char *xrealloc ();
  28
  29 /* Create a new dynamic string capable of holding at least SPACE
  30    characters, including the terminating NUL.  If SPACE is 0, it
  31    will be silently increased to 1.  */
  32
  33 dyn_string_t
  34 dyn_string_new (space)
  35      int space;
  36 {
  37   dyn_string_t result = (dyn_string_t) xmalloc (sizeof (struct dyn_string));
  38
  39   if (space == 0)
  40     /* We need at least one byte in which to store the terminating
  41        NUL.  */
  42     space = 1;
  43
  44   result->allocated = space;
  45   result->s = (char*) xmalloc (space);
  46   result->length = 0;
  47   result->s[0] = '\0';
  48
  49   return result;
  50 }
  51
  52 /* Free the memory used by DS.  */
  53
  54 void
  55 dyn_string_delete (ds)
  56      dyn_string_t ds;
  57 {
  58   free (ds->s);
  59   free (ds);
  60 }
  61
  62 /* Append the NUL-terminated string S to DS, resizing DS if
  63    necessary.  */
  64
  65 dyn_string_t
  66 dyn_string_append (ds, s)
  67      dyn_string_t ds;
  68      char *s;
  69 {
  70   int len = strlen (s);
  71   dyn_string_resize (ds, ds->length + len + 1 /* '\0' */);
  72   strcpy (ds->s + ds->length, s);
  73   ds->length += len;
  74
  75   return ds;
  76 }
  77
  78 /* Increase the capacity of DS so that it can hold at least SPACE
  79    characters, including the terminating NUL.  This function will not
  80    (at present) reduce the capacity of DS.  */
  81
  82 dyn_string_t
  83 dyn_string_resize (ds, space)
  84      dyn_string_t ds;
  85      int space;
  86 {
  87   int new_allocated = ds->allocated;
  88
  89   while (space > new_allocated)
  90     new_allocated *= 2;
  91
  92   if (new_allocated != ds->allocated)
  93     {
  94       /* We actually need more space.  */
  95       ds->allocated = new_allocated;
  96       ds->s = (char*) xrealloc (ds->s, ds->allocated);
  97     }
  98
  99   return ds;
 100 }