1*4882a593Smuzhiyun /* getline.c -- Replacement for GNU C library function getline
2*4882a593Smuzhiyun *
3*4882a593Smuzhiyun * Copyright (C) 1993, 1996, 2001, 2002 Free Software Foundation, Inc.
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * SPDX-License-Identifier: GPL-2.0+
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun /* Written by Jan Brittenson, bson@gnu.ai.mit.edu. */
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun #include <assert.h>
11*4882a593Smuzhiyun #include <stdio.h>
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun /* Always add at least this many bytes when extending the buffer. */
14*4882a593Smuzhiyun #define MIN_CHUNK 64
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun /* Read up to (and including) a TERMINATOR from STREAM into *LINEPTR
17*4882a593Smuzhiyun + OFFSET (and null-terminate it). *LINEPTR is a pointer returned from
18*4882a593Smuzhiyun malloc (or NULL), pointing to *N characters of space. It is realloc'd
19*4882a593Smuzhiyun as necessary. Return the number of characters read (not including the
20*4882a593Smuzhiyun null terminator), or -1 on error or EOF.
21*4882a593Smuzhiyun NOTE: There is another getstr() function declared in <curses.h>. */
getstr(char ** lineptr,size_t * n,FILE * stream,char terminator,size_t offset)22*4882a593Smuzhiyun static int getstr(char **lineptr, size_t *n, FILE *stream,
23*4882a593Smuzhiyun char terminator, size_t offset)
24*4882a593Smuzhiyun {
25*4882a593Smuzhiyun int nchars_avail; /* Allocated but unused chars in *LINEPTR. */
26*4882a593Smuzhiyun char *read_pos; /* Where we're reading into *LINEPTR. */
27*4882a593Smuzhiyun int ret;
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun if (!lineptr || !n || !stream)
30*4882a593Smuzhiyun return -1;
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun if (!*lineptr) {
33*4882a593Smuzhiyun *n = MIN_CHUNK;
34*4882a593Smuzhiyun *lineptr = malloc(*n);
35*4882a593Smuzhiyun if (!*lineptr)
36*4882a593Smuzhiyun return -1;
37*4882a593Smuzhiyun }
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun nchars_avail = *n - offset;
40*4882a593Smuzhiyun read_pos = *lineptr + offset;
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun for (;;) {
43*4882a593Smuzhiyun register int c = getc(stream);
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun /* We always want at least one char left in the buffer, since we
46*4882a593Smuzhiyun always (unless we get an error while reading the first char)
47*4882a593Smuzhiyun NUL-terminate the line buffer. */
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun assert(*n - nchars_avail == read_pos - *lineptr);
50*4882a593Smuzhiyun if (nchars_avail < 2) {
51*4882a593Smuzhiyun if (*n > MIN_CHUNK)
52*4882a593Smuzhiyun *n *= 2;
53*4882a593Smuzhiyun else
54*4882a593Smuzhiyun *n += MIN_CHUNK;
55*4882a593Smuzhiyun
56*4882a593Smuzhiyun nchars_avail = *n + *lineptr - read_pos;
57*4882a593Smuzhiyun *lineptr = realloc(*lineptr, *n);
58*4882a593Smuzhiyun if (!*lineptr)
59*4882a593Smuzhiyun return -1;
60*4882a593Smuzhiyun read_pos = *n - nchars_avail + *lineptr;
61*4882a593Smuzhiyun assert(*n - nchars_avail == read_pos - *lineptr);
62*4882a593Smuzhiyun }
63*4882a593Smuzhiyun
64*4882a593Smuzhiyun if (c == EOF || ferror (stream)) {
65*4882a593Smuzhiyun /* Return partial line, if any. */
66*4882a593Smuzhiyun if (read_pos == *lineptr)
67*4882a593Smuzhiyun return -1;
68*4882a593Smuzhiyun else
69*4882a593Smuzhiyun break;
70*4882a593Smuzhiyun }
71*4882a593Smuzhiyun
72*4882a593Smuzhiyun *read_pos++ = c;
73*4882a593Smuzhiyun nchars_avail--;
74*4882a593Smuzhiyun
75*4882a593Smuzhiyun if (c == terminator)
76*4882a593Smuzhiyun /* Return the line. */
77*4882a593Smuzhiyun break;
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun /* Done - NUL terminate and return the number of chars read. */
81*4882a593Smuzhiyun *read_pos = '\0';
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun ret = read_pos - (*lineptr + offset);
84*4882a593Smuzhiyun return ret;
85*4882a593Smuzhiyun }
86*4882a593Smuzhiyun
getline(char ** lineptr,size_t * n,FILE * stream)87*4882a593Smuzhiyun int getline (char **lineptr, size_t *n, FILE *stream)
88*4882a593Smuzhiyun {
89*4882a593Smuzhiyun return getstr(lineptr, n, stream, '\n', 0);
90*4882a593Smuzhiyun }
91