lib/getline.c

   1 /* getline.c -- Replacement for GNU C library function getline
   2
   3 Copyright (C) 1993 Free Software Foundation, Inc.
   4
   5 This program is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 License, or (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful, but
  11 WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
  18
  19 /* Written by Jan Brittenson, bson@gnu.ai.mit.edu.  */
  20
  21 #ifdef HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #include <stdio.h>
  26 #include <sys/types.h>
  27
  28 #if defined __GNU_LIBRARY__ && defined HAVE_GETDELIM
  29
  30 int
  31 getline (lineptr, n, stream)
  32      char **lineptr;
  33      size_t *n;
  34      FILE *stream;
  35 {
  36   return getdelim (lineptr, n, '\n', stream);
  37 }
  38
  39
  40 #else /* ! have getdelim */
  41
  42 #define NDEBUG
  43 #include <assert.h>
  44
  45 #if STDC_HEADERS
  46 # include <stdlib.h>
  47 #else
  48 char *malloc (), *realloc ();
  49 #endif
  50
  51 /* Always add at least this many bytes when extending the buffer.  */
  52 #define MIN_CHUNK 64
  53
  54 /* Read up to (and including) a TERMINATOR from STREAM into *LINEPTR
  55    + OFFSET (and null-terminate it). *LINEPTR is a pointer returned from
  56    malloc (or NULL), pointing to *N characters of space.  It is realloc'd
  57    as necessary.  Return the number of characters read (not including the
  58    null terminator), or -1 on error or EOF.  */
  59
  60 int
  61 getstr (lineptr, n, stream, terminator, offset)
  62      char **lineptr;
  63      size_t *n;
  64      FILE *stream;
  65      char terminator;
  66      size_t offset;
  67 {
  68   int nchars_avail;             /* Allocated but unused chars in *LINEPTR.  */
  69   char *read_pos;               /* Where we're reading into *LINEPTR. */
  70   int ret;
  71
  72   if (!lineptr || !n || !stream)
  73     return -1;
  74
  75   if (!*lineptr)
  76     {
  77       *n = MIN_CHUNK;
  78       *lineptr = malloc (*n);
  79       if (!*lineptr)
  80         return -1;
  81     }
  82
  83   nchars_avail = *n - offset;
  84   read_pos = *lineptr + offset;
  85
  86   for (;;)
  87     {
  88       register int c = getc (stream);
  89
  90       /* We always want at least one char left in the buffer, since we
  91          always (unless we get an error while reading the first char)
  92          NUL-terminate the line buffer.  */
  93
  94       assert(*n - nchars_avail == read_pos - *lineptr);
  95       if (nchars_avail < 2)
  96         {
  97           if (*n > MIN_CHUNK)
  98             *n *= 2;
  99           else
 100             *n += MIN_CHUNK;
 101
 102           nchars_avail = *n + *lineptr - read_pos;
 103           *lineptr = realloc (*lineptr, *n);
 104           if (!*lineptr)
 105             return -1;
 106           read_pos = *n - nchars_avail + *lineptr;
 107           assert(*n - nchars_avail == read_pos - *lineptr);
 108         }
 109
 110       if (c == EOF || ferror (stream))
 111         {
 112           /* Return partial line, if any.  */
 113           if (read_pos == *lineptr)
 114             return -1;
 115           else
 116             break;
 117         }
 118
 119       *read_pos++ = c;
 120       nchars_avail--;
 121
 122       if (c == terminator)
 123         /* Return the line.  */
 124         break;
 125     }
 126
 127   /* Done - NUL terminate and return the number of chars read.  */
 128   *read_pos = '\0';
 129
 130   ret = read_pos - (*lineptr + offset);
 131   return ret;
 132 }
 133
 134 int
 135 getline (lineptr, n, stream)
 136      char **lineptr;
 137      size_t *n;
 138      FILE *stream;
 139 {
 140   return getstr (lineptr, n, stream, '\n', 0);
 141 }
 142
 143 int
 144 getdelim (lineptr, n, delimiter, stream)
 145      char **lineptr;
 146      size_t *n;
 147      int delimiter;
 148      FILE *stream;
 149 {
 150   return getstr (lineptr, n, stream, delimiter, 0);
 151 }
 152 #endif