1/* Estimate the length of the string generated by a vprintf-like
2 function. Used by vasprintf and xvasprintf.
3 Copyright (C) 1994-2023 Free Software Foundation, Inc.
4
5This file is part of the libiberty library.
6Libiberty is free software; you can redistribute it and/or
7modify it under the terms of the GNU Library General Public
8License as published by the Free Software Foundation; either
9version 2 of the License, or (at your option) any later version.
10
11Libiberty is distributed in the hope that it will be useful,
12but WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14Library General Public License for more details.
15
16You should have received a copy of the GNU Library General Public
17License along with libiberty; see the file COPYING.LIB. If not, write
18to the Free Software Foundation, Inc., 51 Franklin Street - Fifth
19Floor, Boston, MA 02110-1301, USA. */
20
21#ifdef HAVE_CONFIG_H
22#include "config.h"
23#endif
24#include <ansidecl.h>
25#include <stdarg.h>
26#if !defined (va_copy) && defined (__va_copy)
27# define va_copy(d,s) __va_copy((d),(s))
28#endif
29#include <stdio.h>
30#ifdef HAVE_STRING_H
31#include <string.h>
32#endif
33#ifdef HAVE_STDLIB_H
34#include <stdlib.h>
35#else
36extern unsigned long strtoul ();
37#endif
38#include "libiberty.h"
39
40int
41libiberty_vprintf_buffer_size (const char *format, va_list args)
42{
43 const char *p = format;
44 /* Add one to make sure that it is never zero, which might cause malloc
45 to return NULL. */
46 int total_width = strlen (s: format) + 1;
47 va_list ap;
48
49#ifdef va_copy
50 va_copy (ap, args);
51#else
52 memcpy ((void *) &ap, (void *) &args, sizeof (va_list));
53#endif
54
55 while (*p != '\0')
56 {
57 if (*p++ == '%')
58 {
59 while (strchr (s: "-+ #0", c: *p))
60 ++p;
61 if (*p == '*')
62 {
63 ++p;
64 total_width += abs (va_arg (ap, int));
65 }
66 else
67 total_width += strtoul (nptr: p, endptr: (char **) &p, base: 10);
68 if (*p == '.')
69 {
70 ++p;
71 if (*p == '*')
72 {
73 ++p;
74 total_width += abs (va_arg (ap, int));
75 }
76 else
77 total_width += strtoul (nptr: p, endptr: (char **) &p, base: 10);
78 }
79 while (strchr (s: "hlL", c: *p))
80 ++p;
81 /* Should be big enough for any format specifier except %s and floats. */
82 total_width += 30;
83 switch (*p)
84 {
85 case 'd':
86 case 'i':
87 case 'o':
88 case 'u':
89 case 'x':
90 case 'X':
91 case 'c':
92 (void) va_arg (ap, int);
93 break;
94 case 'f':
95 case 'e':
96 case 'E':
97 case 'g':
98 case 'G':
99 (void) va_arg (ap, double);
100 /* Since an ieee double can have an exponent of 307, we'll
101 make the buffer wide enough to cover the gross case. */
102 total_width += 307;
103 break;
104 case 's':
105 total_width += strlen (va_arg (ap, char *));
106 break;
107 case 'p':
108 case 'n':
109 (void) va_arg (ap, char *);
110 break;
111 }
112 p++;
113 }
114 }
115#ifdef va_copy
116 va_end (ap);
117#endif
118 return total_width;
119}
120

source code of libiberty/vprintf-support.c