2 .TH mLib 3 "7 July 1999" "Straylight/Edgeware" "mLib utilities library"
4 mLib \- library of miscellaneous utilities
9 library is a mixed bag of things which the author finds useful in large
10 numbers of programs. As a result, its structure is somewhat arbitrary,
11 and it's accreted extra bits over time rather than actually being
12 designed as a whole. In the author's opinion this isn't too much of a
15 At the most granular level,
17 is split into `modules', each of which has its own header file and
18 manual page. Sometimes there are identifiable `chunks' of several
19 modules which fit together as a whole. Modules and chunks fit into
20 `layers', each depending on the ones below it. The header file for
28 This description is a bit abstract, and
30 as a result of its history, doesn't fit it as well as I might like.
31 Even so, it's not too bad a model really.
33 The rest of this section describes the various chunks and layers.
34 .SS "Exception handling"
35 Right at the bottom, there's a fairly primitive exception handling
36 system. It's provided by the
38 module, and stands alone. It's used mainly by the memory allocation
39 modules to raise exceptions when there's no more memory to be had.
40 .SS "Memory allocation"
43 module provides an abstraction of memory allocation. By writing
44 appropriate arena implementations, a client program can control where
45 and how memory is allocated for various structures.
49 module provides simple veneers onto traditional memory allocation
56 doesn't actually depend on
58 being defined in the library) which raise exceptions when there's not
59 enough memory left. These work through the
61 layer, so that the caller can control memory allocation.
65 module handles efficient allocation of small blocks. It allocates
66 memory in relatively big chunks and divides the chunks up into small
67 blocks before returning them. It keeps lists of differently-sized
68 blocks so allocation and freeing is fast. The downside is that your
69 code must know how big a block is when it's being freed.
73 module (not yet documented) is a simple memory allocation tracker. It
74 can be handy when trying to fix memory leaks.
78 module maintains resource pools which can manage memory and other
79 resources, all of the resources held in a pool being destroyed along
84 module provides some trivial string-manipulation functions which tend to
85 be useful quite often.
89 module implements a dynamic string data type. It works quite quickly
90 and well, and is handy in security-sensitive programs, to prevent
91 buffer-overflows. Dynamic strings are used occasionally through the
92 rest of the library, mainly as output arguments.
96 module provides simple functions for reading and writing binary data to
97 or from fixed-sized buffers.
101 module implements a `pool' of dynamic strings which saves lots of
102 allocation and deallocation when a piece of code has high string
104 .SS "Program identification and error reporting"
107 module remembers the name of the program and supplies it when asked.
108 It's used in error messages and similar things.
112 module emits standard Unixy error messages. It provides functions
116 which the author uses rather a lot.
120 module provides an interface for emitting tracing information with
121 configurable verbosity levels. It needs improving to be able to cope
122 with outputting to the system log.
123 .SS "Other data types"
126 module provides the basics for an extending hashtable implementation.
127 Many different hashtable-based data structures can be constructed with
132 module implements a rather good general-purpose extending hash table.
133 Keys and values can be arbitrary data. It is implemented using
140 which are essentially strings with the property that two atoms have the
141 same address if and only if they have the same text, so they can be used
142 for rapid string comparisons. The
144 module implements a hash table which uses atoms as keys, thus saving
145 time spent hashing and comparing hash keys, and the space used for the
150 module implements dynamically resizing arrays which support Perl-like
151 stack operations efficiently.
152 .SS "Miscellaneous utilities"
155 module calculates CRC values for strings. It used to be used by the
156 symbol table manager as a hash function.
160 module implements a simple but efficient universal hashing family. This
161 is a keyed hash function which provides security against an adversary
162 choosing input to a hash table deliberately to cause collisions.
168 locking with a timeout.
172 module manipulates environment variables stored in a hashtable, and
173 converts between the hashtable and the standard array representation of
174 a process environment.
178 module manipulates file descriptor flags in a fairly painless way.
182 module allows you to easily find out whether a file has changed since
183 the last time you looked at it.
187 module implements a `line buffer', which is an object that emits
188 completed lines of text from an incoming asynchronous data stream. It's
189 remarkably handy in programs that want to read lines from pipes and
190 sockets can't block while waiting for a line-end to arrive. Similarly,
193 module implements a `packet buffer', which waits for packets of given
194 lengths to arrive before dispatching them to a handler.
198 module provides some macros and functions for playing with
199 .BR "struct timeval" .
203 module defines some types and macros for playing with words as chunks of
204 bits. There are portable rotate and shift macros (harder than you'd
205 think), and macros to do loading and storing in known-endian formats.
210 module implements a fairly serious options parser compatible with the
215 module provides a generic structure for reading test vectors from files
216 and running them through functions. I mainly use it for testing
217 cryptographic transformations of various kinds.
218 .SS "Encoding and decoding"
221 module does base64 encoding and decoding, as defined in RFC2045. Base64
222 encodes arbitrary binary data in a reliable way which is resistant to
223 character-set transformations and other mail transport bogosity. The
225 module does base32 encoding and decoding, as defined in RFC2938. This
226 is a mad format which is needed for sha1 URNs, for no good reason. The
228 module does hex encoding and decoding.
232 module does urlencoding and decoding, as defined in RFC1866.
233 Urlencoding encodes arbitrary (but mostly text-like) name/value pairs as
234 a text string containing no whitespace.
235 .SS "Multiplexed I/O"
238 module provides a basis for doing nonblocking I/O in Unix systems. It
239 provides types and functions for receiving events when files are ready
240 for reading or writing, and when timers expire.
244 module implements nonblocking network connections in a way which fits in
247 system. It makes nonblocking connects pretty much trivial.
251 module attaches to the
253 system and sends an event when lines of text arrive from a file. It's
254 useful when reading text from a network connection. Similarly,
256 sents events when packets of given sizes arrive from a file.
260 module introduces signal handling into the multiplexed I/O world.
261 Signals are queued until dispatched through the normal
267 module provides a nonblocking ident (RFC931) client. The
269 module does background hostname and address resolution.
306 Mark Wooding, <mdw@distorted.org.uk>
~mdw / mLib / blob