1 #ifndef INCLUDED_ircd_snprintf_h
2 #define INCLUDED_ircd_snprintf_h
4 * IRC - Internet Relay Chat, include/ircd_snprintf.h
5 * Copyright (C) 2000 Kevin L. Mitchell <klmitch@mit.edu>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2, or (at your option)
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 #ifndef INCLUDED_config_h
26 #ifndef INCLUDED_sys_types_h
27 #include <sys/types.h>
28 #define INCLUDED_sys_types_h
30 #ifndef INCLUDED_stdarg_h
32 #define INCLUDED_stdarg_h
37 /* structure passed as argument for %v conversion */
39 size_t vd_chars; /* number of characters inserted */
40 size_t vd_overflow; /* number of characters that couldn't be */
41 const char *vd_format; /* format string */
42 va_list vd_args; /* arguments for %v */
45 extern int ircd_snprintf(struct Client *dest, char *buf, size_t buf_len,
46 const char *format, ...);
47 extern int ircd_vsnprintf(struct Client *dest, char *buf, size_t buf_len,
48 const char *format, va_list args);
53 ** These functions are intended to be a complete replacement for
54 ** sprintf and sprintf_irc. They are a (nearly) complete
55 ** reimplementation, and of course they're snprintf clones, making it
56 ** more difficult for accidental buffer overflows to crop up.
58 ** First off, what's missing? These functions support all ANSI C
59 ** conversion specifiers and selected ones from ISO 9x, with the
60 ** exception of all floating-point conversions. The floating-point
61 ** conversions are tricky, and will likely be dependent on the
62 ** representation of a floating-point number on a particular
63 ** architecture. While that representation is likely to conform to
64 ** some standard, it is not currently used in ircu, so seemed like a
65 ** good thing to omit, given the difficulty of implementing it.
67 ** There are two more things missing from this implementation that
68 ** would be required by ANSI; the first is support for multibyte
69 ** character strings, and the second is support for locales, neither
70 ** of which have any relevance for ircu, so again omission seemed to
71 ** be a good policy. Additionally, %#x always causes '0x' (or '0X')
72 ** to be printed, even if the number is zero.
74 ** These functions also have some extensions not seen in a
75 ** standards-compliant implementation; technically, the ISO 9x
76 ** extensions fall into this category, for instance. The ISO 9x
77 ** extensions supported are type extensions--%ju, %tu, and %zu, for
78 ** instance; %qu and %hhu are also supported. The extensions added
79 ** for use in ircu are %Tu, which takes a time_t, and the new %C
80 ** conversion, which inserts either a numeric or a nick, dependant on
81 ** the <dest> parameter. The GNU %m extension, which inserts the
82 ** strerror() string corresponding to the current value of errno, is
83 ** also supported, as is a special %v extension, which essentially
84 ** does a recursive call to ircd_snprintf.
86 ** The following description is descended from the Linux manpage for
87 ** the printf family of functions.
89 ** The format string is composed of zero or more directives:
90 ** ordinary characters (not %), which are copied unchanged to the
91 ** output stream; and conversion specifications, each of which results
92 ** in fetching zero or more subsequent arguments. Each conversion
93 ** specification is introduced by the character %. The arguments must
94 ** correspond properly (after type promotion) with the conversion
95 ** specifier. After the %, the following appear in sequence:
97 ** * Zero or more of the following flags:
99 ** # specifying that the value should be converted to an
100 ** "alternate form." For c, d, i, n, p, s, and u conversions,
101 ** this option has no effect. For o conversions, the precision
102 ** of the number is increased to force the first character of the
103 ** output string to a zero (except if a zero value is printed
104 ** with an explicit precision of zero). For x and X conversions,
105 ** the string '0x' (or '0X' for X conversions) is prepended to
106 ** it. For e, E, f, g, and G conversions, the result will always
107 ** contain a decimal point, even if no digits follow it
108 ** (normally, a decimal point appears in the results of those
109 ** conversions only if a digit follows). For g and G
110 ** conversions, trailing zeros are not removed from the result as
111 ** they would otherwise be.
113 ** 0 specifying zero padding. For all conversions except n, the
114 ** converted value is padded on the left with zeros rather than
115 ** blanks. If a precision is given with a numeric conversion (d,
116 ** i, o, u, i, x, and X), the 0 flag is ignored.
118 ** - (a negative field width flag) indicates the converted value is
119 ** to be left adjusted on the field boundary. Except for n
120 ** conversions, the converted value is padded on the right with
121 ** blanks, rather than on the left with blanks or zeros. A -
122 ** overrides a 0 if both are given.
124 ** ' ' (a space) specifying that a blank should be left before a
125 ** positive number produced by a signed conversion (d, e, E, f,
128 ** + specifying that a sign always be placed before a number
129 ** produced by a signed conversion. A + overrides a space if
132 ** * An optional decimal digit string specifying a minimum field
133 ** width. If the converted value has fewer characters than the
134 ** field width, it will be padded with spaces on the left (or right,
135 ** if the left-adjustment flag has been given) to fill out the field
138 ** * An optional precision, in the form of a period (`.') followed by
139 ** an optional digit string. If the digit string is omitted, the
140 ** precision is taken as zero. This gives the minimum number of
141 ** digits to appear for d, i, o, u, x, and X conversions, the number
142 ** of digits to appear after the decimal-point for e, E, and f
143 ** conversions, the maximum number of significant digits for g and G
144 ** conversions, or the maximum number of characters to be printed
145 ** from a string for s conversions.
147 ** * The optional character h, specifying that a following d, i, o, u,
148 ** x, or X conversion corresponds to a short int or unsigned short
149 ** int argument, or that a following n conversion corresponds to a
150 ** pointer to a short int argument. If the h character is given
151 ** again, char is used instead of short int.
153 ** * The optional character l (ell) specifying that a following d, i,
154 ** o, u, x, or X conversion applies to a pointer to a long int or
155 ** unsigned long int argument, or that a following n conversion
156 ** corresponds to a pointer to a long int argument.
158 ** * The character L specifying that a following e, E, f, g, or G
159 ** conversion corresponds to a long double argument, or a following
160 ** d, i, o, u, x, or X conversion corresponds to a long long
161 ** argument. Note that long long is not specified in ANSI C and
162 ** therefore not portable to all architectures.
164 ** * The optional character q. This is equivalent to L.
166 ** * A j character specifying that the following integer (d, i, o, u,
167 ** x, or X) conversion corresponds to an intmax_t argument.
169 ** * A t character specifying that the following integer (d, i, o, u,
170 ** x, or X) conversion corresponds to a ptrdiff_t argument.
172 ** * A z character specifying that the following integer (d, i, o, u,
173 ** x, or X) conversion corresponds to a size_t argument.
175 ** * A T character specifying that the following integer (d, i, o, u,
176 ** x, or X) conversion corresponds to a time_t argument.
178 ** * A character that specifies the type of conversion to be applied.
180 ** A field width or precision, or both, may be indicated by an
181 ** asterisk `*' instead of a digit string. In this case, an int
182 ** argument supplies the field width or precision. A negative field
183 ** width is treated as a left adjustment flag followed by a positive
184 ** field width; a negative precision is treated as though it were
187 ** The conversion specifiers and their meanings are:
189 ** diouxX The int (or appropriate variant) argument is converted
190 ** to signed decimal (d and i), unsigned octal (o),
191 ** unsigned decimal (u), or unsigned hexadecimal (x and
192 ** X) notation. The letters abcdef are used for x
193 ** conversions; the letters ABCDEF are used for X
194 ** conversions. The precision, if any, gives the minimum
195 ** number of digits that must appear; if the converted
196 ** value requires fewer digits, it is padded on the left
199 ** eE [NOT IMPLEMENTED] The double argument is rounded and
200 ** converted in the style [-]d.dddedd where there is one
201 ** digit before the decimal-point character and the
202 ** number of digits after it is equal to the precision;
203 ** if the precision is missing, it is taken as 6; if the
204 ** precision is zero, no decimal-point character appears.
205 ** An E conversion uses the letter E (rather than e) to
206 ** introduce the exponent. The exponent always contains
207 ** at least two digits; if the value is zero, the
210 ** f [NOT IMPLEMENTED] The double argument is rounded and
211 ** converted to decimal notation in the style
212 ** [-]ddd.ddd, where the number of digits after the
213 ** decimal-point character is equal to the precision
214 ** specification. If the precision is missing, it is
215 ** taken as 6; if the precision is explicitly zero, no
216 ** decimal-point character appears. If a decimal point
217 ** appears, at least one digit appears before it.
219 ** g [NOT IMPLEMENTED] The double argument is converted in
220 ** style f or e (or E for G conversions). The precision
221 ** specifies the number of significant digits. If the
222 ** precision is missing, 6 digits are given; if the
223 ** precision is zero, it is treated as 1. Style e is
224 ** used if the exponent from its conversion is less than
225 ** -4 or greater than or equal to the precision.
226 ** Trailing zeros are removed from the fractional part of
227 ** the result; a decimal point appears only if it is
228 ** followed by at least one digit.
230 ** c The int argument is converted to an unsigned char, and
231 ** the resulting character is written.
233 ** s The "char *" argument is expected to be a pointer to
234 ** an array of character type (pointer to a string).
235 ** Characters from the array are written up to (but not
236 ** including) a terminating NUL character; if a precision
237 ** is specified, no more than the number specified are
238 ** written. If a precision is given, no null character
239 ** need be present; if the precision is not specified, or
240 ** is greater than the size of the array, the array must
241 ** contain a terminating NUL character.
243 ** p The "void *" pointer argument is printed in
244 ** hexadecimal (as if by %#x or %#lx).
246 ** n The number of characters written so far is stored into
247 ** the integer indicated by the ``int *'' (or variant)
248 ** pointer argument. No argument is converted.
250 ** m The error message associated with the current value of
251 ** errno is printed as if by %s.
253 ** C The client argument identifier is printed under the
254 ** control of the <dest> argument; if <dest> is NULL or
255 ** is a user, the client's name (nickname or server name)
256 ** is printed; otherwise, the client's network numeric is
259 ** v The argument given must be a pointer to a struct
260 ** VarData with vd_format and vd_args must be initialized
261 ** appropriately. On return, vd_chars will contain the
262 ** number of characters added to the buffer, and
263 ** vd_overflow will contain the number of characters that
264 ** could not be added due to buffer overflow or due to a
267 ** % A `%' is written. No argument is converted. The
268 ** complete conversion specification is `%%'.
270 ** In no case does a non-existent or small field width cause
271 ** truncation of a field; if the result of a conversion is wider than
272 ** the field width, the field is expanded to contain the conversion
276 #endif /* INCLUDED_ircd_snprintf_h */