1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 * The ap_vsnprintf/ap_snprintf functions are based on, and used with the
19 * permission of, the SIO stdio-replacement strx_* functions by Panos
20 * Tsirigotis <panos@alumni.cs.colorado.edu> for xinetd.
23 #ifndef APACHE_AP_SNPRINTF_H
24 #define APACHE_AP_SNPRINTF_H
34 /* stuff marked API_EXPORT is part of the API, and intended for use
38 #define API_EXPORT(type) type
41 /* Stuff marked API_EXPORT_NONSTD is part of the API, and intended for
42 * use by modules. The difference between API_EXPORT and
43 * API_EXPORT_NONSTD is that the latter is required for any functions
44 * which use varargs or are used via indirect function call. This
45 * is to accomodate the two calling conventions in windows dlls.
47 #ifndef API_EXPORT_NONSTD
48 #define API_EXPORT_NONSTD(type) type
51 #if !defined(__GNUC__) || __GNUC__ < 2 || \
52 (__GNUC__ == 2 && __GNUC_MINOR__ < 7) ||\
54 #define __attribute__(__x)
57 /* These macros allow correct support of 8-bit characters on systems which
58 * support 8-bit characters. Pretty dumb how the cast is required, but
59 * that's legacy libc for ya. These new macros do not support EOF like
60 * the standard macros do. Tough.
62 #define ap_isalpha(c) (isalpha(((unsigned char)(c))))
63 #define ap_isdigit(c) (isdigit(((unsigned char)(c))))
64 #define ap_islower(c) (islower(((unsigned char)(c))))
67 /* ap_vformatter() is a generic printf-style formatting routine
68 * with some extensions. The extensions are:
70 * %pA takes a struct in_addr *, and prints it as a.b.c.d
71 * %pI takes a struct sockaddr_in * and prints it as a.b.c.d:port
72 * %pp takes a void * and outputs it in hex
74 * The %p hacks are to force gcc's printf warning code to skip
75 * over a pointer argument without complaining. This does
76 * mean that the ANSI-style %p (output a void * in hex format) won't
77 * work as expected at all, but that seems to be a fair trade-off
78 * for the increased robustness of having printf-warnings work.
80 * Additionally, ap_vformatter allows for arbitrary output methods
81 * using the ap_vformatter_buff and flush_func.
83 * The ap_vformatter_buff has two elements curpos and endpos.
84 * curpos is where ap_vformatter will write the next byte of output.
85 * It proceeds writing output to curpos, and updating curpos, until
86 * either the end of output is reached, or curpos == endpos (i.e. the
89 * If the end of output is reached, ap_vformatter returns the
90 * number of bytes written.
92 * When the buffer is full, the flush_func is called. The flush_func
93 * can return -1 to indicate that no further output should be attempted,
94 * and ap_vformatter will return immediately with -1. Otherwise
95 * the flush_func should flush the buffer in whatever manner is
96 * appropriate, re-initialize curpos and endpos, and return 0.
98 * Note that flush_func is only invoked as a result of attempting to
99 * write another byte at curpos when curpos >= endpos. So for
100 * example, it's possible when the output exactly matches the buffer
101 * space available that curpos == endpos will be true when
102 * ap_vformatter returns.
104 * ap_vformatter does not call out to any other code, it is entirely
105 * self-contained. This allows the callers to do things which are
106 * otherwise "unsafe". For example, ap_psprintf uses the "scratch"
107 * space at the unallocated end of a block, and doesn't actually
108 * complete the allocation until ap_vformatter returns. ap_psprintf
109 * would be completely broken if ap_vformatter were to call anything
110 * that used a pool. Similarly http_bprintf() uses the "scratch"
111 * space at the end of its output buffer, and doesn't actually note
112 * that the space is in use until it either has to flush the buffer
113 * or until ap_vformatter returns.
119 } ap_vformatter_buff;
121 API_EXPORT(int) ap_vformatter(int (*flush_func)(ap_vformatter_buff *),
122 ap_vformatter_buff *, const char *fmt, va_list ap);
124 /* These are snprintf implementations based on ap_vformatter().
126 * Note that various standards and implementations disagree on the return
127 * value of snprintf, and side-effects due to %n in the formatting string.
128 * ap_snprintf behaves as follows:
130 * Process the format string until the entire string is exhausted, or
131 * the buffer fills. If the buffer fills then stop processing immediately
132 * (so no further %n arguments are processed), and return the buffer
133 * length. In all cases the buffer is NUL terminated. The return value
134 * is the number of characters placed in the buffer, excluding the
135 * terminating NUL. All this implies that, at most, (len-1) characters
136 * will be copied over; if the return value is >= len, then truncation
139 * In no event does ap_snprintf return a negative number.
141 API_EXPORT_NONSTD(int) ap_snprintf(char *buf, size_t len, const char *format,...)
142 __attribute__((format(printf,3,4)));
143 API_EXPORT(int) ap_vsnprintf(char *buf, size_t len, const char *format,
150 #endif /* !APACHE_AP_SNPRINTF_H */