1/* getline.c -- Replacement for GNU C library function getline
2
3   Copyright (C) 1993, 1996, 2001-2002 Free Software Foundation, Inc.
4
5   This program is free software: you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by
7   the Free Software Foundation; either version 3 of the License, or
8   (at your option) any later version.
9
10   This program is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13   GNU 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, see <http://www.gnu.org/licenses/>.  */
17
18/* Written by Jan Brittenson, bson@gnu.ai.mit.edu.  */
19
20/* Specification.  */
21#include "getline.h"
22
23#include <stddef.h>
24#include <stdio.h>
25#include <string.h>
26#include <assert.h>
27
28/* Always add at least this many bytes when extending the buffer.  */
29#define MIN_CHUNK 64
30
31/* Reads up to (and including) a TERMINATOR from STREAM into *LINEPTR + OFFSET
32   (and null-terminate it). *LINEPTR is a pointer returned from new [] (or
33   NULL), pointing to *N characters of space.  It is realloc'd as
34   necessary.  Returns the number of characters read (not including the
35   null terminator), or -1 on error or immediate EOF.
36   NOTE: There is another getstr() function declared in <curses.h>.  */
37
38static int
39getstr (char **lineptr, size_t *n, FILE *stream, char terminator, size_t offset)
40{
41  size_t nchars_avail;          /* Allocated but unused chars in *LINEPTR.  */
42  char *read_pos;               /* Where we're reading into *LINEPTR. */
43
44  if (!lineptr || !n || !stream)
45    return -1;
46
47  if (!*lineptr)
48    {
49      *n = MIN_CHUNK;
50      *lineptr = new char[*n];
51    }
52
53  nchars_avail = *n - offset;
54  read_pos = *lineptr + offset;
55
56  for (;;)
57    {
58      register int c = getc (stream);
59
60      /* We always want at least one char left in the buffer, since we
61         always (unless we get an error while reading the first char)
62         NUL-terminate the line buffer.  */
63
64      assert (*n - nchars_avail == (size_t) (read_pos - *lineptr));
65      if (nchars_avail < 2)
66        {
67          if (*n > MIN_CHUNK)
68            *n *= 2;
69          else
70            *n += MIN_CHUNK;
71
72          nchars_avail = *n + *lineptr - read_pos;
73          char *new_line = new char[*n];
74          if (*lineptr)
75            {
76              memcpy (new_line, *lineptr, read_pos - *lineptr);
77              delete[] *lineptr;
78            }
79          *lineptr = new_line;
80          read_pos = *n - nchars_avail + *lineptr;
81          assert (*n - nchars_avail == (size_t) (read_pos - *lineptr));
82        }
83
84      if (c == EOF || ferror (stream))
85        {
86          /* Return partial line, if any.  */
87          if (read_pos == *lineptr)
88            return -1;
89          else
90            break;
91        }
92
93      *read_pos++ = c;
94      nchars_avail--;
95
96      if (c == terminator)
97        /* Return the line.  */
98        break;
99    }
100
101  /* Done - NUL terminate and return the number of chars read.  */
102  *read_pos = '\0';
103
104  return read_pos - (*lineptr + offset);
105}
106
107int
108get_line (char **lineptr, size_t *n, FILE *stream)
109{
110  return getstr (lineptr, n, stream, '\n', 0);
111}
112
113int
114get_delim (char **lineptr, size_t *n, int delimiter, FILE *stream)
115{
116  return getstr (lineptr, n, stream, delimiter, 0);
117}
118