Описание скрипта Vstr

Vstr is a string library, designed so you can work optimally with readv()/writev() for input/output. This means that, for instance, you can readv() data to the end of the string and writev() data from the beginning of the string without having to allocate or move memory.
It also means that the library is completely happy with data that has multiple zero bytes in it.
This design constraint means that unlike most string libraries Vstr doesn't have an internal representation of the string where everything can be accessed from a single (char *) pointer in C, the internal representation is of multiple "blocks" or nodes each carrying some of the data for the string.
This model of representing the data also means that as a string gets bigger the Vstr memory usage only goes up linearly and has no inherent copying (due to other string libraries increasing space for the string via. realloc() the memory usage can be triple the required size and require a complete copy of the string).
It also means that adding, substituting or moving data anywhere in the string can be optimized a lot, to require O(1) copying instead of O(n). Speaking of O(1), it's worth remembering that if you have a Vstr string with caching it is O(1) to get all the data to the writev() system call (the cat example below shows an example of this, the write call is always constant time.
As well as having features directly related to doing IO well it contains functions for:
· a printf like function that is fully ISO 9899:1999 (C99) compliant, also having %m as standard and POSIX i18n parameter number modifiers. It also allows gcc warning compatible customer format specifiers (and includes pre-written custom format specifiers for ipv4 and ipv6 addresses, Vstr strings and more)
· splitting of strings into parameter/record chunks (a la perl).
· substituting data in a Vstr string
· moving data from one Vstr string to another (or within a Vstr string).
· comparing strings (without regard for case, or taking into account version information)
· searching for data in strings (with or without regard for case).
· counting spans of data in a string (the equivalent of strspn() in ISO C).
· converting data in a Vstr (Ie. delete/substitute unprintable characters or making a Vstr string lowercase/uppercase).
· parsing data from a Vstr string (Ie. numbers, or ipv4 addresses).
· easily parsing and wrapping outgoing data in netstrings, for fast and simple (and hence less error prone) network communication
· the ability to cache aspects of data about a Vstr string, to both simplify and speedup use of the string.
· the ability to have empty data as part of the string, this is somewhat useful for representing file transfers as a string as you can represent the file data as empty data in the string.

· Ключевые особенности и характеристики Vstr 1.0.15

· Ограничения Vstr 1.0.15

· Специальные требования Vstr 1.0.15

· История версий и изменений Vstr

· Описание и дополнения от редакторов и пользователей сайта

Связанные статьи, обзоры и новости