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