data structures - What are Pascal Strings? -

Is the name of programming language or mathematician named after him?

What are the defined characteristics of Pascal wire? It seems that the defined attribute is accumulating the length of the string in the first byte. In another article, I need to get an impression.

During an unrelated SO thread, someone has mentioned that what are the advantages of Pascal string on zero-end strings? Or more generally, in what situations do Pascal strings do excellence?

Does Pascal String apply in any other language?

After all, do I have both words ("Pascal string") or only the first ("Pascal wire")? I am a technical author ...

Pascal string is a typical but popularly influential Pascal implementation, designated UCSD therefore The UCSD string is a better word. This is the same implementation that makes bitcoin interpreters popular.

Generally, this is not a specific type, but the basic principle of having first basic principle of character for character data. It is receiving continuous time operation (o (1)) of length rather than scanning the character data for a null character.

Not all Pascals use this concept; IIRC, the original (seventy) conference was for allocation of space pad, and was scanned backwards for a non-space character (to eliminate the wire) This is making it impossible for the place) Also, since the software was used mostly in isolation, all types of schemes were used, often for the implementation / architecture, the benefits Rad was, was based on.

Borland (Turbo Pascal, Delphi and Free Pascal) are usually based on UCSD dialects, and thus there are Pascal strings, Delphi currently has 5 such strings (Short / AN / Wide / Unicode / Open)

On the other hand, this means that in a loop, you need some extra check to check the end of the string.

instead of copying a string using

 , (p ^) p = ^ p2 ^; Inc. (P) Inc. (P2); End;  

is equal to

  (* s ++ = * t ++);  

When using optimal compiler, in C

you need to do this like

  while (LAN> gt; 0 ) Begin ^ ^: p2 ^; Inc. (P) Inc. (P2); December (lane); End;  

Or even

  i: = 1; While starting (i & lt; = len) p [i]: = p2 [i]; Inc. (i); End;  

This has slightly increased the number of instructions given in the Pascal string loop equal to the zero finished string, and adds another live value. In addition, the UCSD was a bytecode (interpreter) code, and the latter code is "safe" based on the use of the Pascal string.

In the case of an architecture that was created in increments (++) operators (such as PDP-8, 11C was originally developed), the pointer version was very cheap, especially optimization Without it. Nowadays compiler optimization can easily detect any of these structures and convert them to the best quality.

More importantly, more security has become more important than in the early 90's, and in general, only redundant strings are being trusted. Because small errors in verification potentially exploit buffer overflow can cause problems. C and its standards dislike the old string usage, and now use the "-n-" versions of the old string routine (strancuffies, etc.), which requires a maximum length to pass. This is very much like a manually managed Pascal string theory, where the programmer should take care to exceed the length (or maximum buffer size).

Length prefix strings are also used extensively in file format, because, obviously, the number of bytes is useful for further reading.