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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 | |
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 | #include <assert.h> | |
22 | #include <stdio.h> | |
23 | ||
24 | /* Always add at least this many bytes when extending the buffer. */ | |
25 | #define MIN_CHUNK 64 | |
26 | ||
27 | /* Read up to (and including) a TERMINATOR from STREAM into *LINEPTR | |
28 | + OFFSET (and null-terminate it). *LINEPTR is a pointer returned from | |
29 | malloc (or NULL), pointing to *N characters of space. It is realloc'd | |
30 | as necessary. Return the number of characters read (not including the | |
31 | null terminator), or -1 on error or EOF. | |
32 | NOTE: There is another getstr() function declared in <curses.h>. */ | |
33 | static int getstr(char **lineptr, size_t *n, FILE *stream, | |
34 | char terminator, size_t offset) | |
35 | { | |
36 | int nchars_avail; /* Allocated but unused chars in *LINEPTR. */ | |
37 | char *read_pos; /* Where we're reading into *LINEPTR. */ | |
38 | int ret; | |
39 | ||
40 | if (!lineptr || !n || !stream) | |
41 | return -1; | |
42 | ||
43 | if (!*lineptr) { | |
44 | *n = MIN_CHUNK; | |
45 | *lineptr = malloc(*n); | |
46 | if (!*lineptr) | |
47 | return -1; | |
48 | } | |
49 | ||
50 | nchars_avail = *n - offset; | |
51 | read_pos = *lineptr + offset; | |
52 | ||
53 | for (;;) { | |
54 | register int c = getc(stream); | |
55 | ||
56 | /* We always want at least one char left in the buffer, since we | |
57 | always (unless we get an error while reading the first char) | |
58 | NUL-terminate the line buffer. */ | |
59 | ||
60 | assert(*n - nchars_avail == read_pos - *lineptr); | |
61 | if (nchars_avail < 2) { | |
62 | if (*n > MIN_CHUNK) | |
63 | *n *= 2; | |
64 | else | |
65 | *n += MIN_CHUNK; | |
66 | ||
67 | nchars_avail = *n + *lineptr - read_pos; | |
68 | *lineptr = realloc(*lineptr, *n); | |
69 | if (!*lineptr) | |
70 | return -1; | |
71 | read_pos = *n - nchars_avail + *lineptr; | |
72 | assert(*n - nchars_avail == read_pos - *lineptr); | |
73 | } | |
74 | ||
75 | if (c == EOF || ferror (stream)) { | |
76 | /* Return partial line, if any. */ | |
77 | if (read_pos == *lineptr) | |
78 | return -1; | |
79 | else | |
80 | break; | |
81 | } | |
82 | ||
83 | *read_pos++ = c; | |
84 | nchars_avail--; | |
85 | ||
86 | if (c == terminator) | |
87 | /* Return the line. */ | |
88 | break; | |
89 | } | |
90 | ||
91 | /* Done - NUL terminate and return the number of chars read. */ | |
92 | *read_pos = '\0'; | |
93 | ||
94 | ret = read_pos - (*lineptr + offset); | |
95 | return ret; | |
96 | } | |
97 | ||
98 | int getline (char **lineptr, size_t *n, FILE *stream) | |
99 | { | |
100 | return getstr(lineptr, n, stream, '\n', 0); | |
101 | } |