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_sys_types_h
24 #include <sys/types.h>
25 #define INCLUDED_sys_types_h
27 #ifndef INCLUDED_stdarg_h
29 #define INCLUDED_stdarg_h
34 /** structure passed as argument for %v conversion */
36 size_t vd_chars; /**< number of characters inserted */
37 size_t vd_overflow; /**< number of characters that couldn't be */
38 const char *vd_format; /**< format string */
39 va_list vd_args; /**< arguments for %v */
44 #define va_copy(DEST, SRC) __va_copy(DEST, SRC)
46 /** Fallback macro to copy to \a DEST from \a SRC. */
47 #define va_copy(DEST, SRC) memcpy(&(DEST), &(SRC), sizeof(DEST))
51 extern int ircd_snprintf(struct Client *dest, char *buf, size_t buf_len,
52 const char *format, ...);
53 extern int ircd_vsnprintf(struct Client *dest, char *buf, size_t buf_len,
54 const char *format, va_list args);
56 /** @fn int ircd_snprintf(struct Client *dest, char *buf, size_t
57 buf_len, const char *format, ...)
59 ** These functions are intended to be a complete replacement for
60 ** sprintf and sprintf_irc. They are a (nearly) complete
61 ** reimplementation, and of course they're snprintf clones, making it
62 ** more difficult for accidental buffer overflows to crop up.
64 ** First off, what's missing? These functions support all ANSI C
65 ** conversion specifiers and selected ones from ISO 9x, with the
66 ** exception of all floating-point conversions. The floating-point
67 ** conversions are tricky, and will likely be dependent on the
68 ** representation of a floating-point number on a particular
69 ** architecture. While that representation is likely to conform to
70 ** some standard, it is not currently used in ircu, so seemed like a
71 ** good thing to omit, given the difficulty of implementing it.
73 ** There are two more things missing from this implementation that
74 ** would be required by ANSI; the first is support for multibyte
75 ** character strings, and the second is support for locales, neither
76 ** of which have any relevance for ircu, so again omission seemed to
77 ** be a good policy. Additionally, %#x always causes '0x' (or '0X')
78 ** to be printed, even if the number is zero.
80 ** These functions also have some extensions not seen in a
81 ** standards-compliant implementation; technically, the ISO 9x
82 ** extensions fall into this category, for instance. The ISO 9x
83 ** extensions supported are type extensions--%ju, %tu, and %zu, for
84 ** instance; %qu and %hhu are also supported. The extensions added
85 ** for use in ircu are %Tu, which takes a time_t, and the new %C
86 ** conversion, which inserts either a numeric or a nick, dependant on
87 ** the <dest> parameter. The GNU %m extension, which inserts the
88 ** strerror() string corresponding to the current value of errno, is
89 ** also supported, as is a special %v extension, which essentially
90 ** does a recursive call to ircd_snprintf.
92 ** The following description is descended from the Linux manpage for
93 ** the printf family of functions.
95 ** The format string is composed of zero or more directives:
96 ** ordinary characters (not %), which are copied unchanged to the
97 ** output stream; and conversion specifications, each of which results
98 ** in fetching zero or more subsequent arguments. Each conversion
99 ** specification is introduced by the character %. The arguments must
100 ** correspond properly (after type promotion) with the conversion
101 ** specifier. After the %, the following appear in sequence:
103 ** <ul><li>Zero or more of the following flags:<dl>
106 ** <dd>specifying that the value should be converted to an
107 ** "alternate form." For c, d, i, n, p, s, and u conversions,
108 ** this option has no effect. For o conversions, the precision
109 ** of the number is increased to force the first character of the
110 ** output string to a zero (except if a zero value is printed
111 ** with an explicit precision of zero). For x and X conversions,
112 ** the string '0x' (or '0X' for X conversions) is prepended to
113 ** it. For e, E, f, g, and G conversions, the result will always
114 ** contain a decimal point, even if no digits follow it
115 ** (normally, a decimal point appears in the results of those
116 ** conversions only if a digit follows). For g and G
117 ** conversions, trailing zeros are not removed from the result as
118 ** they would otherwise be. For C conversions, if the
119 ** destination is local and the origin is a user, the
120 ** nick!user\@host form is used.</dd>
123 ** <dd> specifying zero padding. For all conversions except n, the
124 ** converted value is padded on the left with zeros rather than
125 ** blanks. If a precision is given with a numeric conversion (d,
126 ** i, o, u, i, x, and X), the 0 flag is ignored.</dd>
129 ** <dd>(a negative field width flag) indicates the converted value is
130 ** to be left adjusted on the field boundary. Except for n
131 ** conversions, the converted value is padded on the right with
132 ** blanks, rather than on the left with blanks or zeros. A -
133 ** overrides a 0 if both are given.</dd>
135 ** <dt>' ' (a space)</dt>
136 ** <dd>specifying that a blank should be left before a
137 ** positive number produced by a signed conversion (d, e, E, f,
141 ** <dd>specifying that a sign always be placed before a number
142 ** produced by a signed conversion. A + overrides a space if
143 ** both are used.</dd>
146 ** <dd>specifying that a struct Client name should be preceded by a
147 ** ':' character if the destination is a user.</dd>
150 ** <li>An optional decimal digit string specifying a minimum field
151 ** width. If the converted value has fewer characters than the
152 ** field width, it will be padded with spaces on the left (or right,
153 ** if the left-adjustment flag has been given) to fill out the field
156 ** <li>An optional precision, in the form of a period (`.') followed by
157 ** an optional digit string. If the digit string is omitted, the
158 ** precision is taken as zero. This gives the minimum number of
159 ** digits to appear for d, i, o, u, x, and X conversions, the number
160 ** of digits to appear after the decimal-point for e, E, and f
161 ** conversions, the maximum number of significant digits for g and G
162 ** conversions, or the maximum number of characters to be printed
163 ** from a string for s conversions.</li>
165 ** <li>The optional character h, specifying that a following d, i, o, u,
166 ** x, or X conversion corresponds to a short int or unsigned short
167 ** int argument, or that a following n conversion corresponds to a
168 ** pointer to a short int argument. If the h character is given
169 ** again, char is used instead of short int.</li>
171 ** <li>The optional character l (ell) specifying that a following d, i,
172 ** o, u, x, or X conversion applies to a pointer to a long int or
173 ** unsigned long int argument, or that a following n conversion
174 ** corresponds to a pointer to a long int argument.</li>
176 ** <li>The character L specifying that a following e, E, f, g, or G
177 ** conversion corresponds to a long double argument, or a following
178 ** d, i, o, u, x, or X conversion corresponds to a long long
179 ** argument. Note that long long is not specified in ANSI C and
180 ** therefore not portable to all architectures.</li>
182 ** <li>The optional character q. This is equivalent to L.</li>
184 ** <li>A j character specifying that the following integer (d, i, o, u,
185 ** x, or X) conversion corresponds to an intmax_t argument.</li>
187 ** <li>A t character specifying that the following integer (d, i, o, u,
188 ** x, or X) conversion corresponds to a ptrdiff_t argument.</li>
190 ** <li>A z character specifying that the following integer (d, i, o, u,
191 ** x, or X) conversion corresponds to a size_t argument.</li>
193 ** <li>A T character specifying that the following integer (d, i, o, u,
194 ** x, or X) conversion corresponds to a time_t argument.</li>
196 ** <li>A character that specifies the type of conversion to be applied.</li>
199 ** A field width or precision, or both, may be indicated by an
200 ** asterisk `*' instead of a digit string. In this case, an int
201 ** argument supplies the field width or precision. A negative field
202 ** width is treated as a left adjustment flag followed by a positive
203 ** field width; a negative precision is treated as though it were
206 ** The conversion specifiers and their meanings are:
210 ** <dd>The int (or appropriate variant) argument is converted
211 ** to signed decimal (d and i), unsigned octal (o),
212 ** unsigned decimal (u), or unsigned hexadecimal (x and
213 ** X) notation. The letters abcdef are used for x
214 ** conversions; the letters ABCDEF are used for X
215 ** conversions. The precision, if any, gives the minimum
216 ** number of digits that must appear; if the converted
217 ** value requires fewer digits, it is padded on the left
220 ** <dt>eE [NOT IMPLEMENTED]</dt>
221 ** <dd>The double argument is rounded and
222 ** converted in the style [-]d.dddedd where there is one
223 ** digit before the decimal-point character and the
224 ** number of digits after it is equal to the precision;
225 ** if the precision is missing, it is taken as 6; if the
226 ** precision is zero, no decimal-point character appears.
227 ** An E conversion uses the letter E (rather than e) to
228 ** introduce the exponent. The exponent always contains
229 ** at least two digits; if the value is zero, the
230 ** exponent is 00.</dd>
232 ** <dt>f [NOT IMPLEMENTED]</dt>
233 ** <dd>The double argument is rounded and
234 ** converted to decimal notation in the style
235 ** [-]ddd.ddd, where the number of digits after the
236 ** decimal-point character is equal to the precision
237 ** specification. If the precision is missing, it is
238 ** taken as 6; if the precision is explicitly zero, no
239 ** decimal-point character appears. If a decimal point
240 ** appears, at least one digit appears before it.</dd>
242 ** <dt>g [NOT IMPLEMENTED]</dt>
243 ** <dd>The double argument is converted in
244 ** style f or e (or E for G conversions). The precision
245 ** specifies the number of significant digits. If the
246 ** precision is missing, 6 digits are given; if the
247 ** precision is zero, it is treated as 1. Style e is
248 ** used if the exponent from its conversion is less than
249 ** -4 or greater than or equal to the precision.
250 ** Trailing zeros are removed from the fractional part of
251 ** the result; a decimal point appears only if it is
252 ** followed by at least one digit.</dd>
255 ** <dd>The int argument is converted to an unsigned char, and
256 ** the resulting character is written.</dd>
259 ** <dd>The "char *" argument is expected to be a pointer to
260 ** an array of character type (pointer to a string).
261 ** Characters from the array are written up to (but not
262 ** including) a terminating NUL character; if a precision
263 ** is specified, no more than the number specified are
264 ** written. If a precision is given, no null character
265 ** need be present; if the precision is not specified, or
266 ** is greater than the size of the array, the array must
267 ** contain a terminating NUL character.</dd>
270 ** <dd>The "void *" pointer argument is printed in
271 ** hexadecimal (as if by %#x or %#lx).</dd>
274 ** <dd>The number of characters written so far is stored into
275 ** the integer indicated by the ``int *'' (or variant)
276 ** pointer argument. No argument is converted.</dd>
279 ** <dd>The error message associated with the current value of
280 ** errno is printed as if by %s.</dd>
283 ** <dd>The client argument identifier is printed under the
284 ** control of the <dest> argument; if <dest> is NULL or
285 ** is a user, the client's name (nickname or server name)
286 ** is printed; otherwise, the client's network numeric is
290 ** <dd>The channel argument identifier (channel name) is
294 ** <dd>The argument given must be a pointer to a struct
295 ** VarData with vd_format and vd_args must be initialized
296 ** appropriately. On return, vd_chars will contain the
297 ** number of characters added to the buffer, and
298 ** vd_overflow will contain the number of characters that
299 ** could not be added due to buffer overflow or due to a
303 ** <dd>A `%' is written. No argument is converted. The
304 ** complete conversion specification is `%%'.</dd>
307 ** In no case does a non-existent or small field width cause
308 ** truncation of a field; if the result of a conversion is wider than
309 ** the field width, the field is expanded to contain the conversion
312 ** @param[in] dest Client receiving of message.
313 ** @param[out] buf Output buffer for formatted message.
314 ** @param[in] buf_len Number of bytes that can be written to \a buf.
315 ** @param[in] format Format string for message.
316 ** @return Number of bytes that would be written to \a buf without truncation.
319 #endif /* INCLUDED_ircd_snprintf_h */