contrib/cpio/dstring.c

   1 /* dstring.c - The dynamic string handling routines used by cpio.
   2    Copyright (C) 1990, 1991, 1992 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software
  16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  17
  18 #include <stdio.h>
  19 #if defined(HAVE_STRING_H) || defined(STDC_HEADERS)
  20 #include <string.h>
  21 #else
  22 #include <strings.h>
  23 #endif
  24 #include "dstring.h"
  25
  26 #if __STDC__
  27 # define P_(s) s
  28 #else
  29 # define P_(s) ()
  30 #endif
  31 char *xmalloc P_((unsigned n));
  32 char *xrealloc P_((char *p, unsigned n));
  33
  34 /* Initialiaze dynamic string STRING with space for SIZE characters.  */
  35
  36 void
  37 ds_init (string, size)
  38      dynamic_string *string;
  39      int size;
  40 {
  41   string->ds_length = size;
  42   string->ds_string = (char *) xmalloc (size);
  43 }
  44
  45 /* Expand dynamic string STRING, if necessary, to hold SIZE characters.  */
  46
  47 void
  48 ds_resize (string, size)
  49      dynamic_string *string;
  50      int size;
  51 {
  52   if (size > string->ds_length)
  53     {
  54       string->ds_length = size;
  55       string->ds_string = (char *) xrealloc ((char *) string->ds_string, size);
  56     }
  57 }
  58
  59 /* Dynamic string S gets a string terminated by the EOS character
  60    (which is removed) from file F.  S will increase
  61    in size during the function if the string from F is longer than
  62    the current size of S.
  63    Return NULL if end of file is detected.  Otherwise,
  64    Return a pointer to the null-terminated string in S.  */
  65
  66 char *
  67 ds_fgetstr (f, s, eos)
  68      FILE *f;
  69      dynamic_string *s;
  70      char eos;
  71 {
  72   int insize;                   /* Amount needed for line.  */
  73   int strsize;                  /* Amount allocated for S.  */
  74   int next_ch;
  75
  76   /* Initialize.  */
  77   insize = 0;
  78   strsize = s->ds_length;
  79
  80   /* Read the input string.  */
  81   next_ch = getc (f);
  82   while (next_ch != eos && next_ch != EOF)
  83     {
  84       if (insize >= strsize - 1)
  85         {
  86           ds_resize (s, strsize * 2 + 2);
  87           strsize = s->ds_length;
  88         }
  89       s->ds_string[insize++] = next_ch;
  90       next_ch = getc (f);
  91     }
  92   s->ds_string[insize++] = '\0';
  93
  94   if (insize == 1 && next_ch == EOF)
  95     return NULL;
  96   else
  97     return s->ds_string;
  98 }
  99
 100 char *
 101 ds_fgets (f, s)
 102      FILE *f;
 103      dynamic_string *s;
 104 {
 105   return ds_fgetstr (f, s, '\n');
 106 }
 107
 108 char *
 109 ds_fgetname (f, s)
 110      FILE *f;
 111      dynamic_string *s;
 112 {
 113   return ds_fgetstr (f, s, '\0');
 114 }