1 /* Formatted output to obstacks.
2 Copyright (C) 2008-2012 Free Software Foundation, Inc.
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3, or (at your option)
7 any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License along
15 with this program; if not, see <http://www.gnu.org/licenses/>. */
16
17 #include <config.h>
18
19 /* Specification. */
20 #include <stdio.h>
21
22 #include "obstack.h"
23 #include "vasnprintf.h"
24
25 #include <errno.h>
26 #include <stdarg.h>
27 #include <stdlib.h>
28
29 /* Grow an obstack with formatted output. Return the number of bytes
30 added to OBS. No trailing nul byte is added, and the object should
31 be closed with obstack_finish before use.
32
33 Upon memory allocation error, call obstack_alloc_failed_handler.
34 Upon other error, return -1. */
35 int
obstack_printf(struct obstack * obs,const char * format,...)36 obstack_printf (struct obstack *obs, const char *format, ...)
37 {
38 va_list args;
39 int result;
40
41 va_start (args, format);
42 result = obstack_vprintf (obs, format, args);
43 va_end (args);
44 return result;
45 }
46
47 /* Grow an obstack with formatted output. Return the number of bytes
48 added to OBS. No trailing nul byte is added, and the object should
49 be closed with obstack_finish before use.
50
51 Upon memory allocation error, call obstack_alloc_failed_handler.
52 Upon other error, return -1. */
53 int
obstack_vprintf(struct obstack * obs,const char * format,va_list args)54 obstack_vprintf (struct obstack *obs, const char *format, va_list args)
55 {
56 /* If we are close to the end of the current obstack chunk, use a
57 stack-allocated buffer and copy, to reduce the likelihood of a
58 small-size malloc. Otherwise, print directly into the
59 obstack. */
60 enum { CUTOFF = 1024 };
61 char buf[CUTOFF];
62 char *base = obstack_next_free (obs);
63 size_t len = obstack_room (obs);
64 char *str;
65
66 if (len < CUTOFF)
67 {
68 base = buf;
69 len = CUTOFF;
70 }
71 str = vasnprintf (base, &len, format, args);
72 if (!str)
73 {
74 if (errno == ENOMEM)
75 obstack_alloc_failed_handler ();
76 return -1;
77 }
78 if (str == base && str != buf)
79 /* The output was already computed in place, but we need to
80 account for its size. */
81 obstack_blank_fast (obs, len);
82 else
83 {
84 /* The output exceeded available obstack space or we used buf;
85 copy the resulting string. */
86 obstack_grow (obs, str, len);
87 if (str != buf)
88 free (str);
89 }
90 return len;
91 }
92