lib/linebuffer.c

   1 /* linebuffer.c -- read arbitrarily long lines
   2    Copyright (C) 1986, 1991, 1998, 1999 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 Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Written by Richard Stallman. */
  19 \f
  20 #ifdef HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #include <stdio.h>
  25 #include <sys/types.h>
  26 #include "linebuffer.h"
  27
  28 char *xmalloc ();
  29 char *xrealloc ();
  30 void free ();
  31
  32 /* Initialize linebuffer LINEBUFFER for use. */
  33
  34 void
  35 initbuffer (struct linebuffer *linebuffer)
  36 {
  37   linebuffer->length = 0;
  38   linebuffer->size = 200;
  39   linebuffer->buffer = (char *) xmalloc (linebuffer->size);
  40 }
  41
  42 /* Read an arbitrarily long line of text from STREAM into LINEBUFFER.
  43    Keep the newline; append a newline if it's the last line of a file
  44    that ends in a non-newline character.  Do not null terminate.
  45    Return LINEBUFFER, except at end of file return 0.  */
  46
  47 struct linebuffer *
  48 readline (struct linebuffer *linebuffer, FILE *stream)
  49 {
  50   int c;
  51   char *buffer = linebuffer->buffer;
  52   char *p = linebuffer->buffer;
  53   char *end = buffer + linebuffer->size; /* Sentinel. */
  54
  55   if (feof (stream) || ferror (stream))
  56     return 0;
  57
  58   do
  59     {
  60       c = getc (stream);
  61       if (c == EOF)
  62         {
  63           if (p == buffer)
  64             return 0;
  65           if (p[-1] == '\n')
  66             break;
  67           c = '\n';
  68         }
  69       if (p == end)
  70         {
  71           linebuffer->size *= 2;
  72           buffer = (char *) xrealloc (buffer, linebuffer->size);
  73           p = p - linebuffer->buffer + buffer;
  74           linebuffer->buffer = buffer;
  75           end = buffer + linebuffer->size;
  76         }
  77       *p++ = c;
  78     }
  79   while (c != '\n');
  80
  81   linebuffer->length = p - buffer;
  82   return linebuffer;
  83 }
  84
  85 /* Free linebuffer LINEBUFFER and its data, all allocated with malloc. */
  86
  87 void
  88 freebuffer (struct linebuffer *linebuffer)
  89 {
  90   free (linebuffer->buffer);
  91   free (linebuffer);
  92 }